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Title: A Commentary to Kant's 'Critique of Pure Reason'

Author: Norman Kemp Smith

Release Date: August 27, 2013 [EBook #43572]

Language: English

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Index: A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, Z.
(etext transcriber's note)



K A N T’S  ‘C R I T I Q U E  O F
P U R E  R E A S O N’














The Critique of Pure Reason is more obscure and difficult than even a metaphysical treatise has any right to be. The difficulties are not merely due to defects of exposition; they multiply rather than diminish upon detailed study; and, as I shall endeavour to show in this Commentary, are traceable to two main causes, the composite nature of the text, written at various dates throughout the period 1772-1780, and the conflicting tendencies of Kant’s own thinking.

The Commentary is both expository and critical; and in exposition no less than in criticism I have sought to subordinate the treatment of textual questions and of minor issues to the systematic discussion of the central problems. Full use is made of the various selections from Kant’s private papers that have appeared, at intervals, since the publication of his Lectures on Metaphysics in 1821. Their significance has not hitherto been generally recognised in English books upon Kant. They seem to me to be of capital importance for the right understanding of the Critique.

Some apology is perhaps required for publishing a work of this character at the present moment. It was completed, and arrangements made for its publication, shortly before the outbreak of war. The printers have, I understand, found in it a useful stop-gap to occupy them in the intervals of more pressing work; and now that the type must be released, I trust that in spite of, or even because of, the overwhelming preoccupations of the war, there may be some few readers to whom the volume may be not unwelcome. That even amidst the distractions of actual campaigning metaphysical speculation can serve as a refuge and a solace is shown by the {viii}memorable example of General Smuts. He has himself told us that on his raid into Cape Colony in the South African War he carried with him for evening reading the Critique of Pure Reason. Is it surprising that our British generals, pitted against so unconventional an opponent, should have been worsted in the battle of wits?

The Critique of Pure Reason is a philosophical classic that marks a turning-point in the history of philosophy, and no interpretation, even though now attempted after the lapse of a hundred years, can hope to be adequate or final. Some things are clearer to us than they were to Kant’s contemporaries; in other essential ways our point of view has receded from his, and the historical record, that should determine our judgments, is far from complete. But there is a further difficulty of an even more serious character. The Critique deals with issues that are still controversial, and their interpretation is possible only from a definite standpoint. The limitations of this standpoint and of the philosophical milieu in which it has been acquired unavoidably intervene to distort or obscure our apprehension of the text. Arbitrary and merely personal judgments I have, however, endeavoured to avoid. My sole aim has been to reach, as far as may prove feasible, an unbiassed understanding of Kant’s great work.

Among German commentators I owe most to Vaihinger, Adickes, B. Erdmann, Cohen, and Riehl, especially to the first named. The chief English writers upon Kant are Green, Caird, and Adamson. In so far as Green and Caird treat the Critical philosophy as a half-way stage to the Hegelian standpoint I find myself frequently in disagreement with them; but my indebtedness to their writings is much greater than my occasional criticisms of their views may seem to imply. With Robert Adamson I enjoyed the privilege of personal discussions at a time when his earlier view of Kant’s teaching was undergoing revision in a more radical manner than is apparent even in his posthumously published University lectures. To the stimulus of his suggestions the writing of this Commentary is largely due.

My first study of the Critique was under the genial and inspiring guidance of Sir Henry Jones. With characteristic kindliness he has read through my manuscript and has{ix} disclosed to me many defects of exposition and argument. The same service has been rendered me by Professor G. Dawes Hicks, whose criticisms have been very valuable, particularly since they come from a student of Kant who on many fundamental points takes an opposite view from my own.

I have also to thank my colleague, Professor Oswald Veblen, for much helpful discussion of Kant’s doctrines of space and time, and of mathematical reasoning.

Mr. H. H. Joachim has read the entire proofs, and I have made frequent modifications to meet his very searching criticisms. I have also gratefully adopted his revisions of my translations from the Critique. Similar acknowledgments are due to my colleague, Professor A. A. Bowman, and to my friend Dr. C. W. Hendel.

I have in preparation a translation of the Critique of Pure Reason, and am responsible for the translations of all passages given in the present work. In quoting from Kant’s other writings, I have made use of the renderings of Abbott, Bernard, and Mahaffy; but have occasionally allowed myself the liberty of introducing alterations.

Should readers who are already well acquainted with the Critique desire to use my Commentary for its systematic discussions of Kant’s teaching, rather than as an accompaniment to their study of the text, I may refer them to those sections which receive italicised headings in the table of contents.


London, January 1918.{xi}


I. Textual
      Kant’s Method of composing the Critique of Pure Reasonxix
II. Historical
      Kant’s Relation to Hume and to Leibnizxxv
III. General
      1. The Nature of the a priorixxxiii
      2. Kant’s Contribution to the Science of Logicxxxvi
      3. The Nature of Consciousnessxxxix
      4. Phenomenalism, Kant’s Substitute for Subjectivismxlv
      5. The Distinction between Human and Animal Intelligencexlvii
      6. The Nature and Conditions of Self-Consciousnessl
      7. Kant’s threefold Distinction between Sensibility, Understanding, and Reasonlii
      8. The place of the Critique of Pure Reason in Kant’s Philosophical Systemlv
Dedication to Freiherr von Zedlitz6
Preface To the First Edition8
    Comment on Preface10
    Dogmatism, Scepticism, Criticism13
Preface To the Second Edition17
    The Copernican Hypothesis{xii}22
    Comment upon the Argument of Kant’s Introduction33
    How are Synthetic a priori Judgments possible?43
    The Analytic and Synthetic Methods44
    Purpose and Scope of the Critique56
    Kant’s relation to Hume61
    Meaning of the term Transcendental73
The Transcendental Doctrine of Elements
Part I. The Transcendental Aesthetic79-166
    Definition of Terms79
    Kant’s conflicting Views of Space88
  Section I. Space99
    Kant’s Attitude to the Problems of Modern Geometry117
  Section II. Time123
    Kant’s Views regarding the Nature of Arithmetical Science128
    Kant’s conflicting Views of Time134
    General Observations on the Transcendental Aesthetic143
    The Distinction between Appearance and Illusion148
    Kant’s Relation to Berkeley155
    The Paradox of Incongruous Counterparts161
Part II. The Transcendental Logic167
    I. Logic in General167
    II. Transcendental Logic170
    III. The Division of General Logic into Analytic and Dialectic172
Division I. The Transcendental Analytic174
  Book I. The Analytic of Concepts175
    Chapter I. The Clue to the Discovery of all Pure Concepts of the Understanding175
      Section I. The Logical Use of the Understanding176
        Comment on Kant’s Argument176
        Stages in the Development of Kant’s Metaphysical Deduction186
      Section II. The Logical Function of the Understanding in Judgment192
      Section III. The Categories on Pure Concepts of the Understanding194
        Distinction between Logical Forms and Categories{xiii}195
  Chapter II. Deduction of the Pure Concepts Of The Understanding202
    Analysis of the Text: the Four Stages in the Development of Kant’s Views202-234
    I. Enumeration of the Four Stages203
    II. Detailed Analysis of the Four Stages204
      Kant’s Doctrine of the Transcendental Object204
    III. Evidence yielded by the “Reflexionen” and “Lose Blätter” in Support of the Analysis of the Text231
    IV. Connected Statement and Discussion of Kant’s Subjective and Objective Deductions in the First Edition234
      Distinction between the Subjective and the Objective Deductions235
      The Subjective Deduction in its initial empirical Stages245
      Objective Deduction as given in the First Edition248
      The later Stages of the Subjective Deduction263
      The Distinction between Phenomenalism and Subjectivism270
      Transcendental Deduction of the Categories in the Second Edition284
      The Doctrine of Inner Sense291
      Kant’s Refutations of Idealism298
      Inner Sense and Apperception321
  Book II. The Analytic of Principles332
    Chapter I. The Schematism of Pure Concepts Of the Understanding334
    Chapter II. System of All Principles of Pure Understanding342
    1. The Axioms of Intuition347
    2. The Anticipations of Perception349
    3. The Analogies of Experience355
      A. First Analogy358
      B. Second Analogy363
        Schopenhauer’s Criticism of Kant’s Argument365
        Kant’s Subjectivist and Phenomenalist Views of the Causal Relation373
        Reply to Further Criticisms of Kant’s Argument{xiv}377
        C. Third Analogy381
          Schopenhauer’s Criticism of Kant’s Argument387
    4. The Postulates of Empirical Thought in General391
  Chapter III. On the Ground of the Distinction of all Objects whatever into Phenomena and Noumena404
    Relevant Passages in the Section on Amphiboly410
    Alterations in the Second Edition412
    Comment on Kant’s Argument414
  Appendix. The Amphiboly of the Concepts of Reflection418
  Division II. The Transcendental Dialectic424
          Introductory Comment upon the composite Origin and conflicting Tendencies of the Dialectic425
          The History and Development of Kant’s Views in regard to the Problems of the Dialectic431
    I. Transcendental Illusion441
    II. Pure Reason as the Seat of Transcendental Illusion442
Book I. The Concepts of Pure Reason446
    Section I. Ideas in General447
    Section II. The Transcendental Ideas450
    Section III. System of the Transcendental Ideas453
Book II. The Dialectical Inferences of Pure Reason455
  Chapter I. The Paralogisms of Pure Reason455
          First Paralogism: of Substantiality457
          Second Paralogism: of Simplicity458
          Third Paralogism: of Personality461
          Fourth Paralogism: of Ideality462
      Second Edition Statement of the Paralogisms466
      Is the Notion of the Self a necessary Idea of Reason?473
  Chapter II. The Antinomy of Pure Reason478
    Section I. System of the Cosmological Ideas478
    Section II. Antithetic of Pure Reason480
      Comment on Kant’s Method of Argument481
          First Antinomy483
          Second Antinomy488
          Third Antinomy492
          Fourth Antinomy{xv}495
    Section III. The Interest of Reason in this Self-Conflict498
    Section IV. Of the Transcendental Problems of Pure Reason in so far as they absolutely must be capable of Solution499
    Section V. Sceptical Representation of the Cosmological Questions501
    Section VI. Transcendental Idealism as the Key to the Solution of the Cosmological Dialectic503
    Section VII. Critical Decision of the Cosmological Conflict of Reason with itself504
    Section VIII. The Regulative Principle of Pure Reason in regard to the Cosmological Ideas506
    Section IX. The Empirical Employment of the Regulative Principles of Reason in regard to all Cosmological Ideas508
      Solution of the First and Second Antinomies508
      Remarks on the Distinction between the Mathematical-Transcendental and the Dynamical-Transcendental Ideas510
      Comment on Kant’s Method of Argument510
      Solution of the Third Antinomy512
      Possibility of harmonising Causality through Freedom with the Universal Law of Natural Necessity513
      Explanation of the Relation of Freedom to Necessity of Nature514
      Comment on Kant’s Method of Argument517
      Solution of the Fourth Antinomy518
      Concluding Note on the whole Antinomy of Pure Reason519
      Concluding Comment on Kant’s Doctrine of the Antinomies519
  Chapter III. The Ideal of Pure Reason522
    Section I. and II. The Transcendental Ideal522
      Comment on Kant’s Method of Argument524
    Section III. The Speculative Arguments in Proof of the Existence of a Supreme Being525
    Section IV. The Impossibility of an Ontological Proof527
      Comment on Kant’s Method of Argument{xvi}528
    Section V. The Impossibility of a Cosmological Proof of the Existence of God531
      Comment on Kant’s Method of Argument533
      Discovery and Explanation of the Transcendental Illusion in all Transcendental Proof of the Existence of a necessary Being534
      Comment on Kant’s Method of Argument535
    Section VI. The Impossibility of the Physico-Theological Proof538
    Section VII. Criticism of all Theology based on speculative Principles of Reason541
      Concluding Comment541
Appendix to the Transcendental Dialectic543
  The Regulative Employment of the Ideas of Pure Reason543
  Hypotheses not permissible in Philosophy543
  On the Final Purpose of the Natural Dialectic of Human Reason552
  Concluding Comment on the Dialectic558
Appendix A.
  The Transcendental Doctrine of Methods563
  Chapter I. The Discipline of Pure Reason563
    Section I. The Discipline of Pure Reason in its Dogmatic Employment563
    Section II. The Discipline of Pure Reason in its Polemical Employment567
    Section III. The Discipline of Pure Reason in regard to Hypotheses568
    Section IV. The Discipline of Pure Reason in regard to its Proofs568
  Chapter II. The Canon of Pure Reason569
    Section I. The Ultimate End of the Pure Use of our Reason569
    Section II. The Ideal of the Highest Good, as a Determining Ground of the Ultimate End of Pure Reason570
    Section III. Opining, Knowing, and Believing576
  Chapter III. The Architectonic of Pure Reason579
  Chapter IV. The History of Pure Reason{xvii}582
Appendix B.
    A more detailed Statement of Kant’s Relations to his Philosophical Predecessors583
Index: A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, Z607


In all references to the Kritik der Reinen Vernunft I have given the original pagings of both the first and second editions. References to Kant’s other works are, whenever possible, to the volumes thus far issued in the new Berlin edition. As the Reflexionen Kants zur Kritik der reinen Vernunft had not been published in this edition at the time when the Commentary was completed, the numbering given is that of B. Erdmann’s edition of 1884.


Berlin edition of Kant’s worksW
Pagings in the first edition of the Kritik der reinen Vernunft      A
Pagings in the second editionB
Adickes’ edition of the Kritik der reinen Vernunft (1889)K





SELDOM, in the history of literature, has a work been more conscientiously and deliberately thought out, or more hastily thrown together, than the Critique of Pure Reason. The following is the account which Kant in a letter to Moses Mendelssohn (August 16, 1783) has given of its composition:

”[Though the Critique is] the outcome of reflection which had occupied me for a period of at least twelve years, I brought it to completion in the greatest haste within some four to five months, giving the closest attention to the content, but with little thought of the exposition or of rendering it easy of comprehension by the reader—a decision which I have never regretted, since otherwise, had I any longer delayed, and sought to give it a more popular form, the work would probably never have been completed at all. This defect can, however, be gradually removed, now that the work exists in a rough form.”[2]

These statements must be allowed the greater weight as Kant, in another letter (to Garve, August 7, 1783), has given them in almost the same words:

“I freely admit that I have not expected that my book should meet with an immediate favourable reception. The exposition of the materials which for more than twelve successive years I had been carefully maturing, was not composed in a sufficiently suitable manner for general comprehension. For the perfecting of its exposition several years would have been required, whereas I brought it to completion in some four to five months, in the fear that, on longer delay, so prolonged a labour might finally become burdensome, and that my increasing years (I am already in my sixtieth year) would perhaps incapacitate me, while I am still the sole possessor of my complete system.”[3]


The twelve years here referred to are 1769-1780; the phrase “at least twelve years” indicates Kant’s appreciation of the continuity of his mental development. Hume’s first influence upon Kant is probably to be dated prior to 1760. The choice, however, of the year 1769 is not arbitrary; it is the year of Kant’s adoption of the semi-Critical position recorded in the Inaugural Dissertation (1770).[4] The “four to five months” may be dated in the latter half of 1780. The printing of the Critique was probably commenced in December or January 1780-1781.

But the Critique is not merely defective in clearness or popularity of exposition. That is a common failing of metaphysical treatises, especially when they are in the German language, and might pass without special remark. What is much more serious, is that Kant flatly contradicts himself in almost every chapter; and that there is hardly a technical term which is not employed by him in a variety of different and conflicting senses. As a writer, he is the least exact of all the great thinkers.

So obvious are these inconsistencies that every commentator has felt constrained to offer some explanation of their occurrence. Thus Caird has asserted that Kant opens his exposition from the non-Critical standpoint of ordinary consciousness, and that he discloses the final position, towards which he has all along been working, only through repeated modifications of his preliminary statements. Such a view, however, cannot account either for the specific manner of occurrence or for the actual character of the contradictions of which the Critique affords so many examples. These are by no means limited to the opening sections of its main divisions; and careful examination of the text shows that they have no such merely expository origin. The publication of Kant’s Reflexionen and Lose Blätter, and the devoted labours of Benno Erdmann, Vaihinger, Adickes, Reicke and others, have, indeed, placed the issue upon an entirely new plane. It can now be proved that the Critique is not a unitary work, and that in the five months in which, as Kant tells us, it was “brought to completion” (zu Stande gebracht), it was not actually written, but was pieced together by the combining of manuscripts written at various dates throughout the period 1772-1780.

Kant’s correspondence in these years contains the repeated assertion that he expected to be able to complete the work within some three or six months. This implies that it was already, at least as early as 1777, in great part committed{xxi} to writing. In 1780 Kant must therefore have had a large body of manuscript at his disposal. The recently published Lose Blätter are, indeed, part of it. And as we shall have constant occasion to observe, the Critique affords ample evidence of having been more or less mechanically constructed through the piecing together of older manuscript, supplemented, no doubt, by the insertion of connecting links, and modified by occasional alterations to suit the new context. Kant, it would almost seem, objected to nothing so much as the sacrifice of an argument once consecrated by committal to paper. If it could be inserted, no matter at what cost of repetition, or even confusion, he insisted upon its insertion. Thus the Subjective and Objective Deductions of the first edition can, as we shall find, be broken up into at least four distinct layers, which, like geological strata, remain to the bewilderment of the reader who naturally expects a unified system, but to the enlightenment of the student, once the clues that serve to identify and to date them have been detected. To cite another example: in the Second Analogy, as given in the first edition, the main thesis is demonstrated in no less than five distinct proofs, some of which are repetitions; and when Kant restated the argument in the second edition, he allowed the five proofs to remain, but superimposed still another upon them. Kant does, indeed, in the second edition omit some few passages from various parts of the Critique; but this is in the main owing to his desire to protect himself against serious misunderstanding to which, as he found, he had very unguardedly laid himself open. The alterations of the second edition are chiefly of the nature of additions.

Adickes’ theory[5] that Kant in the “four to five months” composed a brief outline of his entire argument, and that it was upon the framework of this outline that the Critique was elaborated out of the older manuscript, may possibly be correct. It has certainly enabled Adickes to cast much light upon many textual problems. But his own supplementary hypothesis in regard to the section on the Antinomies, namely, that it formed an older and separate treatise, may very profitably be further extended. Surely it is unlikely that with the expectation, continued over many years, of completion within a few months, Kant did not possess, at least for the Aesthetic, Dialectic, and Methodology, a general outline, that dated further back than 1780. And doubtless this outline was itself altered, patched, and recast, in proportion as insight into the problems of the Analytic, the problems, that is to say,{xxii} which caused publication to be so long deferred, deepened and took final form.

The composite character of the Critique is largely concealed by the highly elaborate, and extremely artificial, arrangement of its parts. To the general plan, based upon professedly logical principles, Kant has himself given the title, architectonic; and he carries it out with a thoroughness to which all other considerations, and even at times those of sound reasoning, are made to give way. Indeed, he clings to it with the unreasoning affection which not infrequently attaches to a favourite hobby. He lovingly elaborates even its minor detail, and is rewarded by a framework so extremely complicated that the most heterogeneous contents can be tidily arranged, side by side, in its many compartments. By its uniformity and rigour it gives the appearance of systematic order even when such order is wholly absent.

But we have still to consider the chief reason for the contradictory character of the contents of the Critique. It is inseparably bound up with what may perhaps be regarded as Kant’s supreme merit as a philosophical thinker, especially as shown in the first Critique,—namely, his open-minded recognition of the complexity of his problems, and of the many difficulties which lie in the way of any solution which he is himself able to propound. Kant’s method of working seems to have consisted in alternating between the various possible solutions, developing each in turn, in the hope that some midway position, which would share in the merits of all, might finally disclose itself. When, as frequently happened, such a midway solution could not be found, he developed his thought along the parallel lines of the alternative views.

“You know that I do not approach reasonable objections with the intention merely of refuting them, but that in thinking them over I always weave them into my judgments, and afford them the opportunity of overturning all my most cherished beliefs. I entertain the hope that by thus viewing my judgments impartially from the standpoint of others some third view that will improve upon my previous insight may be obtainable.... Long experience has taught me that insight into a subject which I am seeking to master is not to be forced, or even hastened, by sheer effort, but demands a fairly prolonged period during which I return again and again to the same concepts, viewing them in all their aspects and in their widest possible connections, while in the intervals the sceptical spirit awakens, and makes trial whether my conclusions can withstand a {xxiii}searching criticism.”[6] “In mental labour of so delicate a character nothing is more harmful than preoccupation with extraneous matters. The mind, though not constantly on the stretch, must still, alike in its idle and in its favourable moments, lie uninterruptedly open to any chance suggestion which may present itself. Relaxations and diversions must maintain its powers in freedom and mobility, so that it may be enabled to view the object afresh from every side, and so to enlarge its point of view from a microscopic to a universal outlook that it adopts in turn every conceivable standpoint, verifying the observations of each by means of all the others.”[7] “I am not of the opinion of the well-meaning writer who has recommended us never to allow doubts in regard to a matter upon which we have once made up our minds. In pure philosophy that is not feasible. Indeed the understanding has in itself a natural objection to any such procedure. We must consider propositions in all their various applications; even when they may not seem to require a special proof, we must make trial of their opposites, and in this way fight for delay, until the truth becomes in all respects evident.”[8]

That these are no mere pious expressions of good intention, but represent Kant’s actual method of working, is amply proved by the contents of the Critique. We find Kant constantly alternating between opposed standpoints, to no one of which he quite definitely commits himself, and constantly restating his principles in the effort to remove the objections to which, as he recognises, they continue to lie open. The Critique, as already stated, is not the exposition of a single unified system, but is the record of Kant’s manifold attempts to formulate and to solve his many-sided problems. Even those portions of the Critique which embody his latest views show that Kant is still unwilling to sacrifice insight to consistency. When he is guilty of special pleading—for he cannot be altogether absolved even from that charge—it is in the interests of his logical architectonic, for which, as I have said, he cherishes a quite unreasoning affection, and not of his central principles. So far from concealing difficulties, or unduly dwelling upon the favouring considerations, Kant himself emphasises the outstanding objections to which his conclusions remain subject. If his teaching is on certain points very definite, it is in other hardly less important respects largely tentative.

The value of Kant’s Critique as an introduction to modern philosophy is greatly enhanced by this method of procedure. The student who has steeped himself in the atmosphere of the Critique, however dissatisfied he may perhaps be with many of its doctrines, has become familiar with the main requirements{xxiv} which a really adequate metaphysics must fulfil, or at least will have acquired a due sense of the complexity of the problems with which it deals.

Recognition of the composite nature of the text will safeguard us in two ways. In the first place, citation of single passages is quite inconclusive. Not only must all the relevant passages be collated; they must be interpreted in the light of an historical understanding of the various stages in Kant’s development. We must also be prepared to find that on certain main questions Kant hesitates between opposed positions, and that he nowhere definitively commits himself to any quite final expression of view.

Secondly, we cannot proceed on the assumption that Kant’s maturest teaching comes where, had the Critique been a unitary work, composed upon a definite and previously thought out plan, we should naturally expect to find it, namely, in its concluding portions. The teaching of much of the Dialectic, especially in its account of the nature of the phenomenal world and of its relation to the knowing mind, is only semi-Critical. This is also true of Kant’s Introduction to the Critique. Introductions are usually written last; and probably Kant’s Introduction was written after the completion of the Aesthetic, of the Dialectic, and of the Analytic in its earlier forms. But it bears all the signs of having been composed prior to the working out of several of his most characteristic doctrines in the central parts of the Analytic.

Thus both Kant’s introductory statements of the aims and purposes of the Critique, and his application of his results in the solution of metaphysical problems, fail to represent in any adequate fashion the new and revolutionary principles to which he very gradually but successfully worked his way. The key to the Critique is given in the central portions of the Analytic, especially in the Deduction of the Categories. The other parts of the Critique reveal the Critical doctrines only as gradually emerging from the entangling influence of pre-Critical assumptions. Their teaching has to be radically remodelled before they can be made to harmonise with what, in view both of their intrinsic character and of the corresponding alterations in the second edition, must be regarded as Kant’s maturest utterances.

This was a task which Kant never himself attempted. For no sooner had he attained to comparative clearness in regard to his new Critical principles and briefly expounded them in the Analytic of the first edition, than he hastened to apply them in the spheres of morality, aesthetics, and teleology. When the Critique appeared in 1781 he was fifty-{xxv}seven years of age; and he seems to have feared that if he allowed these purely theoretical problems, which had already occupied his main attention for “at least twelve years,” to detain him longer, he would be debarred from developing and placing on permanent record the new metaphysics of ethics which, as the references in the first Critique show, had already begun to shape itself in his mind. To have expended further energy upon the perfecting of his theoretical philosophy would have endangered its own best fruits. Even the opportunity in 1787 of a second edition of the Critique he used very sparingly, altering or adding only where occasional current criticism—his puzzled contemporaries having still for the most part maintained a discreet silence—had clearly shown that his modes of exposition were incomplete or misleading.



Kant’s manner of formulating his fundamental problem—How are synthetic a priori judgments possible?—may well seem to the modern reader to imply an unduly scholastic and extremely rationalistic method of approach. Kant’s reasons for adopting it have, unfortunately, been largely obscured, owing to the mistaken interpretation which has usually been given to certain of his personal utterances. They have been supposed to prove that the immediate occasion of the above formula was Hume’s discussion of the problem of causality in the Enquiry into the Human Understanding. Kant, it is argued, could not have been acquainted with Hume’s earlier and more elaborate Treatise on Human Nature, of which there was then no translation; and his references to Hume must therefore concern only the later work.

Vaihinger has done valuable service in disputing this reading of Kant’s autobiographical statements. Kant does not himself make direct mention of the Enquiry, and the passages in the Critique and in the Prolegomena[9] in which Hume’s teaching is under consideration seem rather to point to the wider argument of the Treatise. This is a matter of no small importance; for if Vaihinger’s view can be established, it will{xxvi} enable us to appreciate, in a manner otherwise impossible, how Kant should have come to regard the problem of a priori synthesis as being the most pressing question in the entire field of speculative philosophy.

The essential difference between the Treatise and the Enquiry, from the standpoint of their bearing upon Critical issues, lies in the wider scope and more radical character of the earlier work. The Enquiry discusses the problem of causality only in the form in which it emerges in particular causal judgments, i.e. as to our grounds for asserting that this or that effect is due to this or that cause. In the Treatise, Hume raises the broader question as to our right to postulate that events must always be causally determined. In other words, he there questions the validity of the universal causal principle, that whatever begins to exist must have a cause of existence; and he does so on the explicit ground that it demands as necessary the connecting of two concepts, that of an event and that of an antecedent cause, between which no connection of any kind can be detected by the mind. The principle, that is to say, is not self-evident; it is synthetic. The concept of an event and the concept of a cause are quite separate and distinct ideas. Events can be conceived without our requiring to think antecedent events upon which they are dependent. Nor is the principle capable of demonstration. For if it be objected that in questioning its validity we are committing ourselves to the impossible assertion that events arise out of nothing, such argument is only applicable if the principle be previously granted. If events do not require a cause, it is as little necessary to seek their source in a generation out of nothing as in anything positive. Similarly, when it is argued that as all the parts of time and space are uniform, there must be a cause determining an event to happen at one moment and in one place rather than at some other time or place, the principle is again assumed. There is no greater difficulty in supposing the time and place to be fixed without a cause than in supposing the existence to be so determined. The principle, Hume concludes, is non-rational in character. It is an instrument useful for the organisation of experience; and for that reason nature has determined us to its formation and acceptance. Properly viewed, it expresses a merely instinctive belief, and is explicable only in the naturalistic manner of our other propensities, as necessary to the fulfilling of some practical need. “Nature has determined us to judge as well as to breathe and feel.”

From this naturalistic position Hume makes a no less vigorous attack upon the empirical philosophies which profess{xxvii} to establish general principles by inductive inference from the facts of experience. If the principles which lie at the basis of our experience are non-rational in character, the same must be true of our empirical judgments. They may correctly describe the uniformities that have hitherto occurred in the sequences of our sensations, and may express the natural expectations to which they spontaneously give rise; but they must never be regarded as capable of serving as a basis for inference. In eliminating a priori principles, and appealing exclusively to sense-experience, the empiricist removes all grounds of distinction between inductive inference and custom-bred expectation. And since from this standpoint the possibility of universal or abstract concepts—so Hume argues—must also be denied, deductive inference must likewise be eliminated from among the possible instruments at the disposal of the mind. So-called inference is never the source of our beliefs; it is our fundamental natural beliefs, as determined by the constitution of our nature in its reaction upon external influences, that generate those expectations which, however they may masquerade in logical costume, have as purely natural a source as our sensations and feelings. Such, briefly and dogmatically stated, is the sum and substance of Hume’s teaching.[10]

Now it was these considerations that, as it would seem, awakened Kant to the problem of a priori synthesis. He was, and to the very last remained, in entire agreement with Hume’s contention that the principle of causality is neither self-evident nor capable of logical demonstration, and he at once realised that what is true of this principle must also hold of all the other principles fundamental to science and philosophy. Kant further agreed that inductive inference from the data of experience is only possible upon the prior acceptance of rational principles independently established; and that we may not, therefore, look to experience for proof of their validity. Thus with the rejection of self-evidence as a feature of the a priori, and with the consequent admission of its synthetic character, Kant is compelled to acquiesce in the inevitableness of the dilemma which Hume propounds. Either Hume’s sceptical conclusions must be accepted, or we must be able to point to some criterion which is not subject to the defects of the rationalist and empirical methods of proof, and which is adequate to determine the validity or invalidity of general principles. Is there any such alternative? Such is Kant’s problem as{xxviii} expressed in the formula: How are synthetic a priori judgments possible?

It is a very remarkable historical fact that notwithstanding the clearness and cogency of Hume’s argument, and the appearance of such competent thinkers as Thomas Reid in Scotland, Lambert and Crusius in Germany, no less than thirty years should have elapsed before Hume found a single reader capable of appreciating the teaching of the Treatise at its true value.[11] Even Kant himself was not able from his reading of the Enquiry in 1756-1762 to realise the importance and bearing of the main problem.[12] Though in the Enquiry the wider issue regarding the general principle of causality is not raised, the bearing of Hume’s discussion, when interpreted in the light of Kant’s own teaching, is sufficiently clear; and accordingly we cannot be absolutely certain that it was not a re-reading of the Enquiry or a recalling of its argument[13] that suggested to Kant the central problem of his Critical philosophy. The probability, however, is rather that this awakening took place only indirectly through his becoming acquainted with the wider argument of the Treatise as revealed in James Beattie’s extremely crude and unsympathetic criticism of Hume’s philosophy.[14] Beattie had great natural ability, and considerable literary power. His prose writings have a lucidity, a crispness, and a felicity of illustration which go far to explain their widespread popularity in the latter half of the eighteenth century. Their literary quality is, however, more than counterbalanced by the absence of any genuine appreciation{xxix} of the deeper, speculative implications and consequences of the problems discussed. And this being so, he is naturally at his worst in criticising Hume. In insisting, as he does, upon the absurd practical results[15] that would follow from the adoption of Hume’s sceptical conclusions, he is merely exploiting popular prejudice in the philosophical arena. That, however, may be forgiven him, if, as would seem to be the case, the quotations which he gives verbatim from Hume’s Treatise really first revealed to Kant the scope and innermost meaning of Hume’s analysis of the causal problem.

The evidence in support of this contention is entirely circumstantial. The German translation of Beattie’s Essay on the Nature and Immutability of Truth was published at Easter 1772, i.e. in the year in which Kant, in the process of his own independent development, came, as is shown by his famous letter to Herz,[16] to realise the mysterious, problematic character of a priori knowledge of the independently real. He was then, however, still entirely unconscious of the deeper problem which at once emerges upon recognition that a priori principles, quite apart from all question of their objective validity, are synthetic in form. We know that Kant was acquainted with Beattie’s work; for he twice refers to Beattie’s criticism of Hume.[17] What more probable than that he read the translation in the year of its publication, or at least at some time not very long subsequent to the date of the letter to Herz? The passages which Beattie quotes from the Treatise are exactly those that were necessary to reveal the full scope of Hume’s revolutionary teaching in respect to the general principle of causality. There seems, indeed, little doubt that this must have been the channel through which Hume’s influence chiefly acted. Thus at last, by a circuitous path, through the quotations of an adversary, Hume awakened philosophy from its dogmatic slumber,[18] and won for his argument that appreciation which despite its cogency it had for thirty years so vainly demanded.{xxx}

Let us now turn our attention to the rationalist philosophy in which Kant was educated. Hume’s contention that experience cannot by itself justify any inductive inference, forms the natural bridge over which we can best pass to the contrasting standpoint of Leibniz. Hume and Leibniz find common ground in denouncing empiricism. Both agree in regarding it as the mongrel offspring of conflicting principles. If rationalism cannot hold its own, the alternative is not the finding of firm foothold in concrete experience, but only such consolation as a sceptical philosophy may afford.[19] The overthrow of rationalism means the destruction of metaphysics in every form. Even mathematics and the natural sciences will have to be viewed as fulfilling a practical end, not as satisfying a theoretical need. But though Leibniz’s criticism of empiricism is, in its main contention, identical with that of Hume, it is profoundly different both in its orientation and in the conclusions to which it leads. While Hume maintains that induction must be regarded as a non-rational process of merely instinctive anticipation, Leibniz argues to the self-legislative character of pure thought. Sense-experience reveals reality only in proportion as it embodies principles derived from the inherent character of thought itself. Experience conforms to a priori principles, and so can afford an adequate basis for scientific induction.

There is a passage in Hume’s Enquiry which may be employed to illustrate the boldly speculative character of Leibniz’s interpretation of the nature and function of human thought. “Nothing ... [seems] more unbounded than the thought of man, which not only escapes all human power and authority, but is not even restrained within the limits of nature and reality.... While the body is confined to one planet, along which it creeps with pain and difficulty, the thought can in an instant transport us into the most distant regions of the universe.... What never was seen, or heard of, may yet be conceived; nor is anything beyond the power of thought, except what implies an absolute contradiction.” This passage in which Hume means to depict a false belief, already sufficiently condemned by the absurdity of its claims, expresses for Leibniz the wonderful but literal truth. Thought is the revealer of an eternal unchanging reality, and its validity{xxxi} is in no way dependent upon its verification through sense. When Voltaire in his Ignorant Philosopher remarks that “it would be very singular that all nature, all the planets, should obey eternal laws, and that there should be a little animal, five feet high, who, in contempt of these laws, could act as he pleased, solely according to his caprice,”[20] he is forgetting that this same animal of five feet can contain the stellar universe in thought within himself, and has therefore a dignity which is not expressible in any such terms as his size may seem, for vulgar estimation, to imply. Man, though dependent upon the body and confined to one planet, has the sun and stars as the playthings of his mind. Though finite in his mortal conditions, he is divinely infinite in his powers.

Leibniz thus boldly challenges the sceptical view of the function of reason. Instead of limiting thought to the translating of sense-data into conceptual forms, he claims for it a creative power which enables it out of its own resources to discover for itself, not only the actual constitution of the material world, but also the immensely wider realm of possible entities. The real, he maintains, is only one of the many kingdoms which thought discovers for itself in the universe of truth. It is the most comprehensive and the most perfect, but still only one out of innumerable others which unfold themselves to the mind in pure thought. Truth is not the abstracting of the universal aspects in things, not a copy of reality, dependent upon it for meaning and significance. Truth is wider than reality, is logically prior to it, and instead of being dependent upon the actual, legislates for it. Leibniz thus starts from the possible, as discovered by pure thought, to determine in an a priori manner the nature of the real.

This Leibnizian view of thought may seem, at first sight, to be merely the re-emergence of the romantic, rationalistic ideal of Descartes and Malebranche. So to regard it would, however, be a serious injustice. It was held with full consciousness of its grounds and implications, and reality was metaphysically reinterpreted so as to afford it a genuine basis. There was nothing merely mystical and nothing undefined in its main tenets. Leibniz differs from Malebranche in being himself a profound mathematician, the co-discoverer with Newton of the differential calculus. He also differs from Descartes in possessing an absorbing interest in the purely logical aspects of the problem of method; and was therefore equipped in a supreme degree for determining{xxxii} in genuinely scientific fashion the philosophical significance and value of the mathematical disciplines.

Hume and Leibniz are thus the two protagonists that dwarf all others. They realised as neither Malebranche, Locke, nor Berkeley, neither Reid, Lambert, Crusius, nor Mendelssohn ever did, the really crucial issues which must ultimately decide between the competing possibilities. Each maintained, in the manner prescribed by his general philosophy, one of what then appeared to be the only two possible views of the function of thought. The alternatives were these: (a) Thought is merely a practical instrument for the convenient interpretation of our human experience; it has no objective or metaphysical validity of any kind; (b) Thought legislates universally; it reveals the wider universe of the eternally possible; and prior to all experience can determine the fundamental conditions to which that experience must conform. Or to interpret this opposition in logical terms: (a) The fundamental principles of experience are synthetic judgments in which no relation is discoverable between subject and predicate, and which for that reason can be justified neither a priori nor by experience; (b) all principles are analytic, and can therefore be justified by pure thought.

The problem of Kant’s Critique, broadly stated, consists in the examination and critical estimate of these two opposed views. There is no problem, scientific, moral, or religious, which is not vitally affected by the decision which of these alternatives we are to adopt, or what reconciliation of their conflicting claims we hope to achieve. Since Kant’s day, largely owing to the establishment of the evolution theory, this problem has become only the more pressing. The naturalistic, instrumental view of thought seems to be immensely reinforced by biological authority. Thought would seem to be reduced to the level of sense-affection, and to be an instrument developed through natural processes for the practical purposes of adaptation. Yet the counter-view has been no less powerfully strengthened by the victorious march of the mathematical sciences. They have advanced beyond the limits of Euclidean space, defining possibilities such as no experience reveals to us. The Leibnizian view has also been reinforced by the successes of physical science in determining what would seem to be the actual, objective character of the independently real. Kant was a rationalist by education, temperament, and conviction. Consequently his problem was to reconcile Leibniz’s view of the function of thought with Hume’s proof of the synthetic character of the causal{xxxiii} principle. He strives to determine how much of Leibniz’s belief in the legislative power of pure reason can be retained after full justice has been done to Hume’s damaging criticisms. The fundamental principles upon which all experience and all knowledge ultimately rest are synthetic in nature: how is it possible that they should also be a priori? Such is the problem that was Kant’s troublous inheritance from his philosophical progenitors, Hume and Leibniz.[21]


In indicating some of the main features of Kant’s general teaching, I shall limit myself to those points which seem most helpful in preliminary orientation, or which are necessary for guarding against the misunderstandings likely to result from the very radical changes in terminology and in outlook that have occurred in the hundred and thirty years since the publication of the Critique. Statements which thus attempt to present in outline, and in modern terms, the more general features of Kant’s philosophical teaching will doubtless seem to many of my readers dogmatic in form and highly questionable in content. They must stand or fall by the results obtained through detailed examination of Kant’s ipsissima verba. Such justification as I can give for them will be found in the body of the Commentary.


The fundamental presupposition upon which Kant’s argument rests—a presupposition never itself investigated but always assumed—is that universality and necessity cannot be reached by any process that is empirical in character. By way of this initial assumption Kant arrives at the conclusion that the a priori, the distinguishing characteristics of which are universality and necessity, is not given in sense but is imposed by the mind; or in other less ambiguous terms, is not part of the matter of experience but constitutes its form. The matter of experience is here taken as equivalent to sensation; while sensation, in turn, is regarded as being the non-relational.

The explanation of Kant’s failure either to investigate or to prove this assumption has already been indicated. Leibniz{xxxiv} proceeds upon the assumption of its truth no less confidently than Hume, and as Kant’s main task consisted in reconciling what he regarded as being the elements of truth in their opposed philosophies, he very naturally felt secure in rearing his system upon the one fundamental presupposition on which they were able to agree. It lay outside the field of controversy, and possessed for Kant, as it had possessed for Hume and for Leibniz, that authoritative and axiomatic character which an unchallenged preconception tends always to acquire.

The general thesis, that the universal and necessary elements in experience constitute its form, Kant specifies in the following determinate manner. The form is fixed for all experience, that is to say, it is one and the same in each and every experience, however simple or however complex. It is to be detected in consciousness of duration no less than in consciousness of objects or in consciousness of self. For, as Kant argues, consciousness of duration involves the capacity to distinguish between subjective and objective succession, and likewise involves recognition[22] with its necessary component self-consciousness. Or to state the same point of view in another way, human experience is a temporal process and yet is always a consciousness of meaning. As temporal, its states are ordered successively, that is, externally to one another; but the consciousness which they constitute is at each and every moment the awareness of some single unitary meaning by reference to which the contents of the successive experiences are organised. The problem of knowledge may therefore be described as being the analysis of the consciousness of duration, of objectivity, and of self-consciousness, or alternatively as the analysis of our awareness of meaning. Kant arrives at the conclusion that the conditions of all four are one and the same.[23]

Kant thus teaches that experience in all its embodiments and in each of its momentary states can be analysed into an endlessly variable material and a fixed set of relational elements. And as no one of the relational factors can be absent without at once nullifying all the others, they together constitute what must be regarded as the determining form and{xxxv} structure of every mental process that is cognitive in character. Awareness, that is to say, is identical with the act of judgment, and therefore involves everything that a judgment, in its distinction from any mere association of ideas, demands for its possibility.

Kant’s position, when thus stated, differs from that of Leibniz only in its clearer grasp of the issues and difficulties involved, and consequently in the more subtle, pertinacious, and thoroughgoing character of the argument by which it is established. Its revolutionary character first appears when Kant further argues, in extension of the teaching of Hume, that the formal, relational elements are of a synthetic nature. The significance and scope of this conclusion can hardly be exaggerated. No other Kantian tenet is of more fundamental importance.[24] With it the main consequences of Kant’s Critical teaching are indissolubly bound up. As the principles which lie at the basis of our knowledge are synthetic, they have no intrinsic necessity, and cannot possess the absolute authority ascribed to them by the rationalists. They are prescribed to human reason, but cannot be shown to be inherently rational in any usual sense of that highly ambiguous term. They can be established only as brute conditions, verifiable in fact though not demonstrable in pure theory (if there be any such thing), of our actual experience. They are conditions of sense-experience, and that means of our knowledge of appearances, never legitimately applicable in the deciphering of ultimate reality. They are valid within the realm of experience, useless for the construction of a metaphysical theory of things in themselves. This conclusion is reinforced when we recognise that human experience, even in its fundamental features (e.g. the temporal and the spatial), might conceivably be altogether different from what it actually is, and that its presuppositions are always, therefore, of the same contingent character. Even the universality and necessity which Kant claims to have established for his a priori principles are of this nature. Their necessity is always for us extrinsic; they can be postulated only if, and so long as, we are assuming the occurrence of human sense-experience.

Thus Kant is a rationalist of a new and unique type. He believes in, and emphasises the importance of, the a priori. With it alone, he contends, is the Critique competent to deal. But it is an a priori which cannot be shown to be more than {xxxvi}relative. It does, indeed, enable us to conceive the known as relative, and to entertain in thought the possibility of an Absolute; but this it can do without itself possessing independent validity. For though the proof of the a priori is not empirical in the sense of being inductive, neither is it logical in the sense of being deduced from necessities of thought. Its “transcendental” proof can be executed only so long as experience is granted as actual; and so long as the fundamental characteristics of this experience are kept in view.

Lastly, the a priori factors are purely relational. They have no inherent content from which clues bearing on the supersensible can be obtained. Their sole function is to serve in the interpretation of contents otherwise supplied.

The a priori, then, is merely relational, without inherent content; it is synthetic, and therefore incapable of independent or metaphysical proof; it is relative to an experience which is only capable of yielding appearances. The a priori is as merely factual as the experience which it conditions.

Even in the field of morality Kant held fast to this conviction. Morality, no less than knowledge, presupposes a priori principles. These, however, are never self-evident, and cannot be established by any mere appeal to intuition. They have authority only to the extent to which they can be shown to be the indispensable presuppositions of a moral consciousness that is undeniably actual.[25]

That the a priori is of this character must be clearly understood. Otherwise the reader will be pursued by a feeling of the unreality, of the merely historical or antiquarian significance, of the entire discussion. He may, if he pleases, substitute the term formal or relational for a priori. And if he bears in mind that by the relational Kant is here intending those elements in knowledge which render possible the relations constitutive of meaning, he will recognise that the Critical discussion is by no means antiquated, but still remains one of the most important issues in the entire field of philosophical enquiry.


The above conclusions have an important bearing upon logical doctrine. Just as modern geometry originates in a sceptical treatment of the axiom of parallels, so modern, idealist logic rests upon Kant’s demonstration of the revolutionary {xxxvii}consequences of Hume’s sceptical teaching. If principles are never self-evident, and yet are not arrived at by induction from experience, by what alternative method can they be established? In answer to this question, Kant outlines the position which is now usually entitled the Coherence theory of truth.[26] That theory, though frequently ascribed to Hegel, has its real sources in the Critique of Pure Reason. It expresses that modification in the Leibnizian rationalism which is demanded by Hume’s discovery of the synthetic character of the causal axiom. Neither the deductive methods of the Cartesian systems nor the inductive methods of the English philosophies can any longer be regarded as correctly describing the actual processes of scientific proof.

General principles are either presuppositions or postulates. If a priori, they are presupposed in all conscious awareness; as above indicated, they have a de facto validity within the experience which they thus make possible. If more special in nature, they are the postulates to which we find ourselves committed in the process of solving specific problems; and they are therefore discovered by the method of trial and failure.[27] They are valid in proportion as they enable us to harmonise appearances, and to adjudicate to each a kind of reality consistent with that assigned to every other.

Proof of fact is similar in general character. The term fact is eulogistic, not merely descriptive; it marks the possession of cognitive significance in regard to some body of knowledge, actual or possible. It can be applied to particular appearances only in so far as we can determine their conditions, and can show that as thus conditioned the mode of their existence is relevant to the enquiry that is being pursued. The convergence of parallel lines is fact from the standpoint of psychological investigation; from the point of view of their physical existence it is merely appearance. Ultimately, of course, everything is real, including what we entitle appearance;[28] but in the articulation of human experience such distinctions are indispensable, and the criteria that define them are prescribed by the context in which they are being employed.

Thus facts cannot be established apart from principles, nor principles apart from facts. The proof of a principle is its adequacy to the interpretation of all those appearances that can be shown to be in any respect relevant to it, while the test of an asserted fact, i.e. of our description of a given appearance, is its conformity to the principles that make insight possible.

Though the method employed in the Critique is entitled{xxxviii} by Kant the “transcendental method,” it is really identical in general character with the hypothetical method of the natural sciences. It proceeds by enquiring what conditions must be postulated in order that the admittedly given may be explained and accounted for.[29] Starting from the given, it also submits its conclusions to confirmation by the given. Considered as a method, there is nothing metaphysical or high-flying about it save the name. None the less, Kant is in some degree justified in adopting the special title. In view of the unique character of the problem to be dealt with, the method calls for very careful statement, and has to be defended against the charge of inapplicability in the philosophical field.

The fundamental thesis of the Coherence theory finds explicit formulation in Kant’s doctrine of the judgment: the doctrine, that awareness is identical with the act of judging, and that judgment is always complex, involving both factual and interpretative elements. Synthetic, relational factors are present in all knowledge, even in knowledge that may seem, on superficial study, to be purely analytic or to consist merely of sense-impressions. Not contents alone, but contents interpreted in terms of some specific setting, are the sole possible objects of human thought. Even when, by forced abstraction, particulars and universals are held mentally apart, they are still being apprehended through judgments, and therefore through mental processes that involve both. They stand in relations of mutual implication within a de facto system; and together they constitute it.

This is the reason why in modern logic, as in Kant’s Critique, the theory of the judgment receives so much more attention than the theory of reasoning. For once the above view of the judgment has been established, all the main points in the doctrine of reasoning follow of themselves as so many corollaries. Knowledge starts neither from sense-data nor from general principles, but from the complex situation in which the human race finds itself at the dawn of self-consciousness. That situation is organised in terms of our mental equipment; and this already existing, rudimentary system is what has made practicable further advance; to create a system ab initio is altogether impossible. The starting-point does not, however, by itself alone determine our conclusions. Owing to the creative activities of the mind, regulative principles are active in all consciousness; and under their guidance the experienced order, largely practical in satisfaction of the instinctive desires, is transformed into a comprehended{xxxix} order, controlled in view of Ideal ends. Logic is the science of the processes whereby this transformation is brought about. An essentially metaphysical discipline, it cannot be isolated from the general body of philosophical teaching; it is not formal, but transcendental; in defining the factors and processes that constitute knowledge, its chief preoccupation is with ultimate issues.

In calling his new logic “transcendental” Kant, it is true, also intends to signify that it is supplementary to, not a substitute for, the older logic, which he professes to accept.[30] Moreover his intuitional theory of mathematical science, his doctrine of the “pure concept,” his attributive view of the judgment—all of them survivals from his pre-Critical period[31]—frequently set him at cross-purposes with himself. His preoccupation, too, with the problem of the a priori leads him to underestimate the part played in knowledge by the merely empirical. But despite all inconsistencies, and notwithstanding his perverse preference for outlandish modes of expression, he succeeds in enforcing with sufficient clearness the really fundamental tenets of the Coherence view.


I shall now approach Kant’s central position from another direction, namely, as an answer to the problem of the nature of consciousness. We are justified, I think, in saying that Kant was the first in modern times to raise the problem of the nature of awareness, and of the conditions of its possibility. Though Descartes is constantly speaking of consciousness, he defines it in merely negative terms, through its opposition to matter; and when he propounds the question how material bodies can be known by the immaterial mind, his mode of dealing with it shows that his real interest lies not in the nature of consciousness but in the character of the existences which it reveals. His answer, formulated in terms of the doctrine of representative perception, and based on the supposed teaching of physics and physiology, is that material bodies through their action on the sense-organs and brain generate images or duplicates of themselves. These images, existing not in outer space but only in consciousness, are, he asserts, mental in nature; and being mental they are, he would seem to conclude, immediately and necessarily apprehended by the mind. Thus Descartes gives us, not an analysis{xl} of the knowing process, but only a subjectivist interpretation of the nature of the objects upon which it is directed.

Quite apart, then, from the question as to whether Descartes’ doctrine of representative perception rests on a correct interpretation of the teaching of the natural sciences—Kant was ultimately led to reject the doctrine—it is obvious that the main epistemological problem, i.e. the problem how awareness is possible, and in what it consists, has so far not so much as even been raised. Descartes and his successors virtually assume that consciousness is an ultimate, unanalysable form of awareness, and that all that can reasonably be demanded of the philosopher is that he explain what objects are actually presented to it, and under what conditions their presentation can occur. On Descartes’ view they are conditioned by antecedent physical and physiological processes; according to Berkeley they are due to the creative activity of a Divine Being; according to Hume nothing whatsoever can be determined as to their originating causes. But all three fail to recognise that even granting the objects to be of the character asserted, namely, mental, the further problem still remains for consideration, how they come to be consciously apprehended, and in what such awareness consists.

Certain interpretations of the nature of the knowing process are, of course, to be found in the writings of Descartes and his successors. But they are so much a matter of unexamined presupposition that they never receive exact formulation, and alternate with one another in quite a haphazard fashion. We may consider three typical views.

1. There is, Descartes frequently seems to imply—the same assumption is evident throughout Locke’s Essay—a self that stands behind all mental states, observing and apprehending them. Consciousness is the power which this self has of contemplating both itself and its ideas. Obviously this is a mere ignoring of the issue. If we assume an observer, we ipso facto postulate a process of observation, but we have not explained or even defined it.

2. There is also in Descartes a second, very different, view of consciousness, namely, as a diaphanous medium analogous to light. Just as light is popularly conceived as revealing the objects upon which it falls, so consciousness is regarded as revealing to us our inner states. This view of consciousness, for reasons which I shall indicate shortly, is entirely inadequate to the facts for which we have to account. It is no more tenable than the corresponding view of light.

3. In Hume we find this latter theory propounded in what may at first sight seem a more satisfactory form, but is even{xli} less satisfactory. Sensations, images, feelings, he argues, are states of consciousness, one might almost say pieces of consciousness, i.e. they are conceived as carrying their own consciousness with them. Red, for instance, is spoken of as a sensation, and is consequently viewed both as being a sense-content, i.e. something sensed or apprehended, and also at the same time as the sensing or awareness of it. This view is unable to withstand criticism. There is really no more ground for asserting that red colour carries with it consciousness of itself than for saying that a table does. The illegitimacy of the assertion is concealed from us by the fact that tables appear to exist when there is no consciousness present, whereas redness cannot be proved to exist independently of consciousness—it may or may not do so. Many present-day thinkers, continuing the tradition of the English associationists, hold to this pre-Kantian view. Sensations, feelings, etc., are, it is implied, pieces of consciousness, forms of awareness; through their varying combinations they constitute the complex experiences of the animal and human mind.

Kant’s teaching is developed in direct opposition to all such views. If we discard his antiquated terminology, and state his position in current terms, we find that it amounts to the assertion that consciousness is in all cases awareness of meaning. There is no awareness, however rudimentary or primitive, that does not involve the apprehension of meaning. Meaning and awareness are correlative terms; each must be studied in its relation to the other. And inasmuch as meaning is a highly complex object of apprehension, awareness cannot be regarded as ultimate or as unanalysable. It can be shown to rest upon a complexity of generative conditions and to involve a variety of distinct factors.

There are thus, from the Kantian standpoint, two all-sufficient reasons why the diaphanous view of consciousness, i.e. any view which treats consciousness merely as a medium whereby the existent gets itself reported, must be regarded as untenable. In the first place, as already remarked, it is based on the false assumption that consciousness is an ultimate, and that we are therefore dispensed from all further investigation of its nature. Kant claims to have distinguished successfully the many components which go to constitute it; and he also professes to have shown that until such analysis has been made, there can be no sufficient basis for a philosophical treatment either of the problems of sense-perception or of the logical problems of judgment and inference. The diaphanous view, with its mirror-like mode of representation, might allow of the side-by-sideness of{xlii} associated contents; it can never account for the processes whereby the associated contents come to be apprehended.

Secondly, the diaphanous view ignores the fundamental distinction between meaning and existence. Existences rest, so to speak, on their own bottom; they are self-centred even at the very moment of their reaction to external influences. Meaning, on the other hand, always involves the interpretation of what is given in the light of wider considerations that lend it significance. In the awareness of meaning the given, the actually presented, is in some way transcended, and this transcendence is what has chiefly to be reckoned with in any attempt to explain the conscious process. Kant is giving expression to this thesis when he contends that all awareness, no matter how rudimentary or apparently simple, is an act of judgment, and therefore involves the relational categories. Not passive contemplation but active judgment, not mere conception but inferential interpretation, is the fundamental form, and the only form, in which our consciousness exists. This, of course, commits Kant to the assertion that there is no mode of cognition that can be described as immediate or unreflective. There is an immediate element in all knowledge, but our consciousness of it is always conditioned and accompanied by interpretative processes, and in their absence there can be no awareness of any kind.

By way of this primary distinction between existence and meaning Kant advances to all those other distinctions which characterise our human experience, between appearance and reality, between the real and the Ideal, between that which is judged and the criteria which control and direct the judging process. Just because all awareness is awareness of meaning, our human experience becomes intelligible as a purposive activity that directs itself according to Ideal standards.

The contrast between the Kantian and the Cartesian views of consciousness can be defined in reference to another important issue. The diaphanous view commits its adherents to a very definite interpretation of the nature of relations. Since they regard consciousness as passive and receptive, they have to maintain that relations can be known only in so far as they are apprehended in a manner analogous to the contents themselves. I do not, of course, wish to imply that this view of relational knowledge is in all cases and in all respects illegitimate. Kant, as we shall find, has carried the opposite view to an impossible extreme, assuming without further argument that what has been shown to be true of certain types of relation (for instance, of the causal and{xliii} substance-attribute relations) must be true of all relations, even of those that constitute space and time. It cannot be denied that, as William James and others have very rightly insisted, such relations as the space-relations are in some degree or manner presentational. This does not, however, justify James in concluding, as he at times seems inclined to do, that all relations are directly experienced. Such procedure lays him open to the same charge of illegitimate reasoning. But even if we could grant James’s thesis in its widest form, the all-important Critical question would still remain: in what does awareness, whether of presented contents or of presented relations, consist, and how is it possible? In answering this question Kant is led to the conclusion that consciousness must be regarded as an activity, and as supplying certain of the conditions of its own possibility. Its contribution is of a uniform and constant nature; it consists, as already noted, of certain relational factors whose presence can be detected in each and every act of awareness.

There is one other respect in which Kant’s view of consciousness differs from that of his Cartesian predecessors.[32] Consciousness, he maintains, does not reveal itself, but only its objects. In other words, there is no awareness of awareness. So far as our mental states and processes can be known at all, they are known in the same objective manner in which we apprehend existences in space.[33] Now if that be so, a very important consequence follows. If there is no awareness of awareness, but only of meanings all of which are objective, there can be no consciousness of the generative, synthetic processes that constitute consciousness on its subjective side. For consciousness, being an act of awareness in which meaning is apprehended, has a twofold nature, and must be very differently described according to the aspect which at any one time we may have in view. When we regard it on its objective side as awareness of meaning, we are chiefly concerned with the various factors that are necessary to meaning and that enter into its constitution. That is to say, our analysis is essentially logical. When, on the other hand, we consider consciousness as an act of awareness, our problem is ontological or as it may be entitled (though the term is in this reference somewhat misleading, since the enquiry as defined by Kant is essentially metaphysical) psychological in character. Between these two aspects {xliv}there is this very important difference. The logical factors constitutive of meaning can be exhaustively known; they are elements in the meanings which consciousness reveals; whereas the synthetic processes are postulated solely in view of these constituent factors, and in order to account for them. The processes, that is to say, are known only through that which they condition, and on Kant’s teaching we are entirely ruled out from attempting to comprehend even their possibility.[34] They must be thought as occurring, but they cannot be known, i.e. their nature cannot be definitely specified. The postulating of them marks a gap in our knowledge, and extends our insight only in the degree that it discloses our ignorance. As consciousness rests upon, and is made possible by, these processes, it can never be explained in terms of the objective world to which our sense-experience, and therefore, as Kant argues, our specific knowledge, is exclusively limited. The mind can unfold its contents in the sunshine of consciousness, only because its roots strike deep into a soil that the light does not penetrate. These processes, thus postulated, Kant regards as the source of the a priori elements, and as the agency through which the synthetic connections necessary to all consciousness are brought about.

According to Kant’s Critical teaching, therefore, consciousness, though analysable, is not such as can ever be rendered completely comprehensible. When all is said, it remains for us a merely de facto form of existence, and has to be taken just for what it presents itself as being. It is actually such as to make possible the logical processes of judgment and inference. It is actually such as to render possible a satisfactory proof of the scientific validity, within the field of sense-experience, of the principle of causality, and of such other principles as are required in the development of the positive sciences. It is also such as to render comprehensible the controlling influence of Ideal standards. But when we come to the question, how is consciousness of this type and form possible, that is, to the question of its metaphysical significance and of the generative conditions upon which it rests, we find, Kant maintains, that we have no data sufficient to justify any decisive answer.{xlv}

The ontological, creative, or dynamical aspect of consciousness, I may further insist, must be constantly borne in mind if the Critical standpoint is to be properly viewed. The logical analysis is, indeed, for the purposes of the central portions of the Critique much the more important, and alone allows of detailed, exhaustive development; but the other is no less essential for an appreciation of Kant’s attitude towards the more strictly metaphysical problems of the Dialectic.

Hegel and his disciples have been the chief culprits in subordinating, or rather in entirely eliminating, this aspect of Kant’s teaching. Many of the inconsistencies of which they accuse Kant exist only if Kant’s teaching be first reduced to a part of itself. To eliminate the ontological implications of his theory of consciousness is, by anticipation, to render many of his main conclusions entirely untenable, and in particular to destroy the force of his fundamental distinction between appearance and reality. If consciousness knows itself in its ultimate nature—and such is Hegel’s contention—one half of reality is taken out of the obscurity in which, on Kant’s reading of the situation, it is condemned to lie hidden. Man is more knowable than nature, and is the key to nature; such is Hegel’s position, crudely stated. Contrast therewith the teaching of Kant. We can know nature more completely (though still very incompletely) than we can ever hope to comprehend the conditions that make possible and actual man’s spiritual life. The moral consciousness is an autonomously acting source of independent values, and though a standing miracle, must be taken for all that on independent and separate enquiry it is found to be. Hegel, in his endeavour to establish an intellectual monism, does violence to some of the highest interests which he professes to be safeguarding. Kant, while outlining in Idea a Kingdom of Ends, remains satisfied with a pluralistic distinction between the intellectual and the moral categories. The antithesis of the two philosophies is in some degree the ancient opposition between Aristotle and Plato, restated in modern terms.


The revolutionary character of the above conclusions is shown by the difficulty which Kant himself found in breaking away from many of the presuppositions that underlie the views which he was renouncing; and this is nowhere more evident than in his constant alternation throughout the{xlvi} Critique between a subjectivism[35] that is thoroughly Cartesian—we might almost, allowing for his rationalism, say Berkeleian—in character, and a radically different position which may be entitled phenomenalism. The latter is alone genuinely Critical, and presents Kant’s teaching in its maturest form. For though first formulated only in those portions of the Analytic that are late in date of writing, and in those passages of the second edition which supplement them, it would seem to be the only logical outcome of Kant’s other main doctrines.

I have especially in mind Kant’s fundamental distinction between appearance and reality; it has an all-important bearing upon the Cartesian opposition between the mental and the material, and especially upon the question as to what view ought to be taken of our so-called subjective experiences. The objective is for the Cartesians the independently real; the subjective is asserted to have an altogether different kind of existence in what is named the field of consciousness. Kant’s phenomenalist restatement of this distinction is too complex and subtle to be made intelligible in the brief space available in this Introduction—it is expounded in the body of the Commentary[36]—but its general character I may indicate in a few sentences. All subjectivist modes of stating the problem of knowledge, such as we find in Hume and in Leibniz no less than in Descartes, Locke, and Berkeley, are, Kant finally concluded, illegitimate and question-begging. Our so-called subjective states, whether they be sensations, feelings, or desires, are objective in the sense that they are objects for consciousness.[37] Our mental states do not run parallel with the system of natural existences; nor are they additional to it. They do not constitute our consciousness of nature; they are themselves part of the natural order which consciousness reveals. They compose the empirical self which is an objective existence, integrally connected with the material environment in terms of which alone it can be understood. The subjective is not opposite in nature to the objective, but a sub-species within it. While, however, the psychical is thus to be regarded as a class of known appearances, and as forming together with the physical a single{xlvii} system of nature, this entire order is, in Kant’s view, conditioned by an underlying realm of noumenal existence; and when the question of the possibility of the knowing, that is, of the experiencing of such a comprehensive natural system, is raised, it is to this noumenal sphere that we are referred. Everything experienced, even a sensation or feeling, is an event, but the experiencing of it is an act of awareness, and calls for an explanation of an altogether different kind.

Thus the problem of knowledge, stated in adequate Critical terms, is not how we can advance from the merely subjective to knowledge of the independently real,[38] but how, if everything known forms part of a comprehensive natural system, consciousness and the complex factors which contribute to its possibility are to be interpreted. On this latter question, as already indicated, Kant, though debarring both subjectivism and materialism, otherwise adopts a non-committal attitude. So long as we continue within the purely theoretical domain, there are a number of alternatives between which there are no sufficient data for deciding. To debar subjectivism is not to maintain the illusory or phenomenal character of the individual self; and to rule out materialism is not to assert that the unconscious may not generate and account for the conscious. In other words, they are ruled out not for any ulterior reasons derived from their supposed metaphysical consequences, but solely because they are based on palpable misinterpretations of the cognitive situation that generates those very problems to which they profess to be an answer.


The inwardness of Kant’s Critical standpoint may perhaps be made clearer by a brief consideration of his view of animal intelligence. We are accustomed nowadays to test a psychology of human consciousness by its capacity to render conceivable an evolution from lower forms. How does Kant’s teaching emerge from such a test?

It may at once be admitted that Kant has made no special study of animal behaviour, and was by no means competent to speak with authority in regard to its conditions. Indeed it is evident that anything which he may have to say upon this{xlviii} question is entirely of the nature of a deduction from results obtained in the human sphere. But when this has been admitted, and we are therefore prepared to find the problems approached from the point of view of the difference rather than of the kinship between man and the animals, we can recognise that, so far as the independent study of human consciousness is concerned, there is a certain compensating advantage in Kant’s pre-Darwinian standpoint. For it leaves him free from that desire which exercises so constant, and frequently so deleterious an influence, upon many workers in the field of psychology, namely, to maintain at all costs, in anticipation of conclusions not yet by any means established, the fundamental identity of animal and human intelligence. This besetting desire all too easily tends to the minimising of differences that may perhaps with fuller insight be found to involve no breach of continuity, but which in the present state of our knowledge cannot profitably be interpreted save in terms of their differentiating peculiarities.

The current controversy between mechanism and vitalism enforces the point which I desire to make. Biological problems, as many biologists are now urging, can be most profitably discussed in comparative independence of ultimate issues, entirely in view of their own domestic circumstances. For only when the actual constitution of organic compounds has been more completely determined than has hitherto been possible can the broader questions be adequately dealt with. In other words, the differences must be known before the exact nature and degree of the continuity can be defined. They cannot be anticipated by any mere deduction from general principles.

The value of Kant’s analysis of human consciousness is thus closely bound up with his frank recognition of its inherent complexity. Not simplification, but specification, down to the bedrock of an irreducible minimum of correlated factors, is the governing motive of his Critical enquiries. His results have therefore the great advantage of being inspired by no considerations save such as are prescribed by the actual subject-matter under investigation. As already noted, Kant maintains that human consciousness is always an awareness of meaning, and that consequently it can find expression only in judgments which involve together with their other factors the element of recognition or self-consciousness.

This decides for Kant the character of the distinction to be drawn between animal and human intelligence. As animals, in his view, cannot be regarded as possessing a capacity of self-consciousness, they must also be denied all awareness of{xlix} meaning. However complicated the associative organisation of their ideas may be, it never rises to the higher level of logical judgment. For the same reason, though their ideas may be schematic in outline, and in their bearing on behaviour may therefore have the same efficiency as general concepts, they cannot become universal in the logical sense. “Animals have apprehensions, but not apperceptions, and cannot, therefore, make their representations universal.”[39] In support of this position Kant might have pointed to the significant fact that animals are so teachable up to a certain point, and so unteachable beyond it. They can be carried as far as associative suggestion will allow, but not a step further. To this day it remains true—at least I venture the assertion—that no animal has ever been conclusively shown to be capable of apprehending a sign as a sign. Animals may seem to do so owing to the influence of associated ideas, but are, as it would appear, debarred from crossing the boundary line which so sharply distinguishes associative suggestion from reflective knowledge.

But Kant is committed to a further assertion. If animals are devoid of all awareness of meaning, they must also be denied anything analogous to what we must signify by the term consciousness. Their experience must fall apart into events, that may, perhaps, be described as mental, but cannot be taken as equivalent to an act of awareness. “Apprehensio bruta without consciousness,”[40] such is Kant’s view of the animal mind. Its mental states, like all other natural existences, are events in time, explicable in the same naturalistic fashion as the bodily processes by which they are conditioned; they can not be equated with that human consciousness which enables us to reflect upon them, and to determine the conditions of their temporal happening.

The distinction which Kant desires to draw is ultimately that between events and consciousness of events. Even if events are psychical in character, consisting of sensations and feelings, there will still remain as fundamental the distinction between what is simply a member of the causal series of natural events and the consciousness through which the series is apprehended. Kant’s most explicit statements occur in a letter to Herz.[41] He is referring to data of the senses which cannot be self-consciously apprehended:

“I should not be able to know that I have them, and they would therefore be for me, as a cognitive being, absolutely nothing.{l} They might still (if I conceive myself as an animal) exist in me (a being unconscious of my own existence) as representations ..., connected according to an empirical law of association, exercising influence upon feeling and desire, and so always disporting themselves with regularity, without my thereby acquiring the least cognition of anything, not even of these my own states.”[42]

As to whether Kant is justified in maintaining that the distinction between animal and human consciousness coincides with the distinction between associative and logical or reflective thinking, I am not concerned to maintain. This digression has been introduced solely for the purpose of defining more precisely the central tenets of Kant’s Critical teaching.


We have still to consider what is perhaps the most serious of all the misunderstandings to which Kant has laid himself open, and which is in large part responsible for the widespread belief that his Critical principles, when consistently developed, must finally eventuate in some such metaphysics as that of Fichte and Hegel. I refer to the view that Kant in postulating synthetic processes as conditioning consciousness is postulating a noumenal self as exercising these activities, and is therefore propounding a metaphysical explanation of the synthetic, a priori factors in human experience.[43]

Kant’s language is frequently ambiguous. The Leibnizian spiritualism, to which in his pre-Critical period he had unquestioningly held, continued to influence his terminology, and so to prevent his Critical principles from obtaining consistent expression. This much can be said in support of the above interpretation of Kant’s position. But in all other respects such a reading of his philosophy is little better than a parody of his actual teaching. For Kant is very well aware that the problem of knowledge is not to be solved in any such easy and high-handed fashion. In the Critique he teaches quite explicitly that to profess to explain the presence of{li} a priori factors in human experience by means of a self assumed for that very purpose would be a flagrant violation, not only of Critical principles, but even of the elementary maxims of scientific reasoning. In the first place, explanation by reference to the activities of such a self would be explanation by faculties, by the unknown; it is a cause that will explain anything and everything equally well or badly.[44] Self-consciousness has, indeed, to be admitted as a fact;[45] and from its occurrence Kant draws important conclusions in regard to the conditions which make experience possible. But, in so doing, Kant never intends to maintain that we are justified in postulating as part of those conditions, or as condition of those conditions, a noumenal self. The conditions which make experience possible, whatever they may be, are also the conditions which make self-consciousness possible. Since the self is known only as appearance, it cannot be asserted to be the conditioning ground of appearance.

This first objection is not explicitly stated by Kant, but it is implied in a second argument which finds expression both in the Deduction of the Categories and in the chapter on the Paralogisms. The only self that we know to exist is the conscious self. Now, as Kant claims to have proved, the self can be thus conscious, even of itself, only in so far as it is conscious of objects. Consequently we have no right to assume that the self can precede such consciousness as its generating cause. That would be to regard the self as existing prior to its own conditions, working in darkness to create itself as a source of light.

But there is also a third reason why Kant’s Critical solution of the problem of knowledge must not be stated in spiritualist terms. Self-consciousness, as he shows, is itself relational in character. It is a fundamental factor in human experience,{lii} not because the self can be shown to be the agency to which relations are due, but solely because, itself a case of recognition, it is at the same time a necessary condition of recognition, and recognition is indispensably presupposed in all consciousness of meaning.[46] Awareness of meaning is the fundamental mystery, and retains its profoundly mysterious character even when self-consciousness has been thus detected as an essential constituent. For self-consciousness does not explain the possibility of meaning; it is itself, as I have just remarked, only one case of recognition, and so is itself only an instance, though indeed the supreme and most important instance, of what we must intend by the term meaning. All awareness, not excepting that of the knowing self, rests upon noumenal conditions whose specific nature it does not itself reveal. Only on moral grounds, never through any purely theoretical analysis of cognitive experience, can it be proved that the self is an abiding personality, and that in conscious, personal form it belongs to the order of noumenal reality.


Even so summary a statement of Critical teaching as I am attempting in this Introduction would be very incomplete without some reference to Kant’s threefold distinction between the forms of sensibility, the categories of the understanding, and the Ideas of Reason.

On investigating space and time Kant discovers that they cannot be classed either with the data of the bodily senses or with the concepts of the understanding. They are sensuous (i.e. are not abstract but concrete, not ways of thinking but modes of existence), yet at the same time are a priori. They thus stand apart by themselves. Each is unique in its kind, is single, and is an infinite existence. To describe them is to combine predicates seemingly contradictory. In Kant’s own phrase, they are monstrosities (Undinge), none the less incomprehensible that they are undeniably actual. To them, primarily, are due those problems which have been a standing challenge to philosophy since the time of Zeno the Eleatic, and which Kant has entitled “antinomies of Reason.”

In contrast of sensibility Kant sets the intellectual faculties, understanding and Reason. In the understanding originate certain pure concepts, or as he more usually names them,{liii} categories. The chief of these are the categories of “relation”—substance, causality and reciprocity. They combine with the forms of sensibility and the manifold of sense to yield the consciousness of an empirical order, interpretable in accordance with universal laws.

To the faculty of Reason Kant ascribes what he entitles Ideas. The Ideas differ from space, time, and the categories in being not “constitutive” but “regulative.” They demand an unconditionedness of existence and a completeness of explanation which can never be found in actual experience. Their function is threefold. In the first place, they render the mind dissatisfied with the haphazard collocations of ordinary experience, and define the goal for its scientific endeavours. Secondly, they determine for us the criteria that distinguish between truth and falsity.[47] And thirdly, in so doing, they likewise make possible the distinction between appearance and reality, revealing to us an irreconcilable conflict between the ultimate aims of science and the human conditions, especially the spatial and temporal conditions under which these aims are realised. The Ideas of Reason are the second main factor in the “antinomies.”

The problem of the Critique, the analysis of our awareness of meaning, is a single problem, and each of the above elements involves all the others. Kant, however, for reasons into which I need not here enter, has assigned part of the problem to what he entitles the Transcendental Aesthetic, and another part to the Transcendental Dialectic. Only what remains is dealt with in what is really the most important of the three divisions, the Transcendental Analytic. But as the problem is one and indivisible, the discussions in all three sections are condemned to incompleteness save in so far as Kant, by happy inconsistency, transgresses the limits imposed by his method of treatment. The Aesthetic really does no more than prepare the ground for the more adequate analysis of space and time given in the Analytic and Dialectic, while the problem of the Analytic is itself incompletely stated until the more comprehensive argument of the Dialectic is taken into account.[48] Thus the statement in the Aesthetic that space and time are given to the mind by the sensuous faculty of{liv} receptivity is modified in the Analytic through recognition of the part which the syntheses and concepts of the understanding must play in the construction of these forms; and in the Dialectic their apprehension is further found to involve an Idea of Reason. Similarly, in the concluding chapter of the Analytic, in discussing the grounds for distinguishing between appearance and reality, Kant omits all reference to certain important considerations which first emerge into view in the course of the Dialectic. Yet, though no question is more vital to Critical teaching, the reader is left under the impression that the treatment given in the Analytic is complete and final.

Partly as a consequence of this, partly owing to Kant’s inconsistent retention of earlier modes of thinking, there are traceable throughout the Critique two opposed views of the nature of the distinction between appearance and reality. On the one view, this distinction is mediated by the relational categories of the understanding, especially by that of causality; on the other view, it is grounded in the Ideas of Reason. The former sets appearance in opposition to reality; the latter regards the distinction in a more tenable fashion, as being between realities less and more comprehensively conceived.[49]

A similar defect is caused by Kant’s isolation of immanent from transcendent metaphysics.[50] The former is dealt with only in the Analytic, the latter only in the Dialectic. The former, Kant asserts, is made possible by the forms of sensibility and the categories of the understanding; the latter he traces to an illegitimate employment of the Ideas of Reason. Such a mode of statement itself reveals the impossibility of any sharp distinction between the immanent and the transcendent. If science is conditioned by Ideals which arouse the mind to further acquisitions, and at the same time reveal the limitations to which our knowledge is for ever condemned to remain subject; if, in other words, everything known, in being correctly known, must be apprehended as appearance (i.e. as a subordinate existence within a more comprehensive reality), the distinction between the immanent and the transcendent falls within and not beyond the domain of our total experience. The meaning which our consciousness discloses in each of its judgments is an essentially metaphysical one. It involves the thought, though not the knowledge, of something more than what the experienced can ever itself be found to be. The metaphysical is immanent in our knowledge; the transcendent is merely a name{lv} for this immanent factor when it is falsely viewed as capable of isolation and of independent treatment. By Kant’s own showing, the task of the Dialectic is not merely to refute the pretensions of transcendent metaphysics, but to develop the above general thesis, in confirmation of the positive conclusions established in the Analytic. The Critique will then supply the remedy for certain evils to which the human mind has hitherto been subject.

The Critique of Pure Reason is a preservative against a malady which has its source in our rational nature. This malady is the opposite of the love of home (the home-sickness) which binds us to our fatherland. It is a longing to pass out beyond our immediate confines and to relate ourselves to other worlds.”[51]


The positive character of Kant’s conclusions cannot be properly appreciated save in the wider perspectives that open to view in the Critique of Practical Reason and in the Critique of Judgment. Though in the Critique of Pure Reason a distinction is drawn between theoretical and moral belief, it is introduced in a somewhat casual manner, and there is no clear indication of the far-reaching consequences that follow in its train. Unfortunately also, even in his later writings, Kant is very unfair to himself in his methods of formulating the distinction. His real intention is to show that scientific knowledge is not coextensive with human insight; but he employs a misleading terminology, contrasting knowledge with faith, scientific demonstration with practical belief.

As already indicated, the term knowledge has, in the Critical philosophy, a much narrower connotation than in current speech. It is limited to sense-experience, and to such inferences therefrom as can be obtained by the only methods that Kant is willing to recognise, namely, the mathematico-physical. Aesthetic, moral and religious experience, and even organic phenomena, are excluded from the field of possible knowledge.

In holding to this position, Kant is, of course, the child of his time. The absolute sufficiency of the Newtonian physics is a presupposition of all his utterances on this theme. Newton, he believes, has determined in a quite final manner the principles, methods and limits of scientific investigation. For though Kant himself imposes upon science a further{lvi} limitation, namely, to appearances, he conceives himself, in so doing, not as weakening Newton’s natural philosophy, but as securing it against all possible objections. And to balance the narrow connotation thus assigned to the term knowledge, he has to give a correspondingly wide meaning to the terms faith, moral belief, subjective principles of interpretation. If this be not kept constantly in mind, the reader is certain to misconstrue the character and tendencies of Kant’s actual teaching.

But though the advances made by the sciences since Kant’s time have rendered this mode of delimiting the field of knowledge altogether untenable, his method of defining the sources of philosophical insight has proved very fruitful, and has many adherents at the present day. What Kant does—stated in broad outline—is to distinguish between the problems of existence and the problems of value, assigning the former to science and the latter to philosophy.[52] Theoretical philosophy, represented in his system by the Critique of Pure Reason, takes as its province the logical values, that is, the distinction of truth and falsity, and defining their criteria determines the nature and limits of our theoretical insight. Kant finds that these criteria enable us to distinguish between truth and falsity only on the empirical plane. Beyond making possible a distinction between appearance and reality, they have no applicability in the metaphysical sphere.

The Critique of Practical Reason deals with values of a very different character. The faculty of Reason, which, as already noted,[53] renders our consciousness a purposive agency controlled by Ideal standards, is also, Kant maintains, the source of the moral sanctions. But whereas in the theoretical field it subdues our minds to the discipline of experience, and restrains our intellectual ambitions within the limits of the empirical order, it here summons us to sacrifice every natural impulse and every secular advantage to the furtherance of an end that has absolute value. In imposing duties, it raises our life from the “pragmatic”[54] level of a calculating expediency to the higher plane of a categorical imperative.

The categorical imperative at once humbles and exalts; it discloses our limitations, but does so through the greatness of the vocation to which it calls us.

“This principle of morality, just on account of the universality of the legislation which makes it the formal supreme determining principle of our will, without regard to any subjective differences, is{lvii} declared by the Reason to be a law for all rational beings.... It is, therefore, not limited to men only, but applies to all finite beings that possess Reason and Will; nay, it even includes the Infinite Being as the Supreme Intelligence.”[55]

Consequently, in employing moral ends in the interpretation of the Universe, we are not picturing the Divine under human limitations, but are discounting these limitations in the light of the one form of value that is known to us as absolute.

Duty! ... What origin is worthy of thee and where is to be found the root of thy noble descent ... a root to be derived from which is the indispensable condition of the only worth that men can give themselves.”[56]

In his earlier years Kant had accepted the current, Leibnizian view that human excellence consists in intellectual enlightenment, and that it is therefore reserved for an élite, privileged with the leisure and endowed with the special abilities required for its enjoyment. From this arid intellectualism he was delivered through the influence of Rousseau.

“I am by disposition an enquirer. I feel the consuming thirst for knowledge, the eager unrest to advance ever further, and the delights of discovery. There was a time when I believed that this is what confers real dignity upon human life, and I despised the common people who know nothing. Rousseau has set me right. This imagined advantage vanishes. I learn to honour men, and should regard myself as of much less use than the common labourer, if I did not believe that my philosophy will restore to all men the common rights of humanity.”[57]

These common rights Kant formulates in a purely individualist manner. For here also, in his lack of historic sense and in his distrust alike of priests and of statesmen, he is the child of his time. In the education and discipline of the soul he looks to nothing so artificial and humanly limited—Kant so regards them—as religious tradition and social{lviii} institutions. Human rights, he believes, do not vary with time and place; and for their enjoyment man requires no initiation and no equipment beyond what is supplied by Nature herself. It is from this standpoint that Kant adduces, as the twofold and sufficient inspiration to the rigours and sublimities of the spiritual life, the starry heavens above us and the moral law within. They are ever-present influences on the life of man. The naked eye reveals the former; of the latter all men are immediately aware. In their universal appeal they are of the very substance of human existence. Philosophy may avail to counteract certain of the hindrances which prevent them from exercising their native influence; it cannot be a substitute for the inspiration which they alone can yield.

Thus the categorical imperative, in endowing the human soul with an intrinsic value, singles it out from all other natural existences, and strengthens it to face, with equanimity, the cold immensities of the cosmic system. For though the heavens arouse in us a painful feeling of our insignificance as animal existences, they intensify our consciousness of a sublime destiny, as bearers of a rival, and indeed a superior, dignity.

In one fundamental respect Kant broke with the teaching of Rousseau, namely, in questioning his doctrine of the natural goodness and indefinite perfectibility of human nature.[58] Nothing, Kant maintains, is good without qualification except the good will; and even that, perhaps, is never completely attained in any single instance. The exercise of duty demands a perpetual vigilance, under the ever-present consciousness of continuing demerit.

“I am willing to admit out of love of humanity that most of our actions are indeed correct, but if we examine them more closely we everywhere come upon the dear self which is always prominent....”[59] “Nothing but moral fanaticism and exaggerated self-conceit is infused into the mind by exhortation to actions as noble, sublime and magnanimous. Thereby men are led into the delusion that it is not duty, that is, respect for the law, whose yoke ... they must bear, whether they like it or not, that constitutes the determining principle of their actions, and which always humbles them while{lix} they obey it. They then fancy that those actions are expected from them, not from duty, but as pure merit.... In this way they engender a vain high-flying fantastic way of thinking, flattering themselves with a spontaneous goodness of heart that needs neither spur nor bridle, nor any command....”[60]

In asserting the goodness and self-sufficiency of our natural impulses Rousseau is the spokesman of a philosophy which has dominated social and political theory since his day, and which is still prevalent. This philosophy, in Kant’s view, is disastrous in its consequences. As a reading of human nature and of our moral vocation, it is hardly less false than the Epicurean teaching, which finds in the pursuit of pleasure the motive of all our actions. A naturalistic ethics, in either form, is incapacitated, by the very nature of its controlling assumptions, from appreciating the distinguishing features of the moral consciousness. Neither the successes nor the failures of man’s spiritual endeavour can be rightly understood from any such standpoint. The human race, in its endurance and tenacity, in its dauntless courage and in its soaring spirit, reveals the presence of a prevenient influence, non-natural in character; and only if human nature be taken as including this higher, directive power, can it assume to itself the eulogy which Rousseau so mistakenly passes upon the natural and undisciplined tendencies of the human heart. For as history demonstrates, while men are weak, humanity is marvellous.

“There is one thing in our soul which, when we take a right view of it, we cannot cease to regard with the highest astonishment, and in regard to which admiration is right and indeed elevating, and that is our original moral capacity in general.... Even the incomprehensibility of this capacity,[61] a capacity which proclaims a Divine origin, must rouse man’s spirit to enthusiasm and strengthen it for any sacrifices which respect for his duty may impose on him.”[62]

We are not here concerned with the detail of Kant’s ethical teaching, or with the manner in which he establishes the freedom of the will, and justifies belief in the existence of God and the immortality of the soul. In many respects his argument lies open to criticism. There is an unhappy{lx} contrast between the largeness of his fundamental thesis and the formal, doctrinaire manner in which it is developed. Indeed, in the Critique of Practical Reason the individualist, deistic, rationalistic modes of thinking of his time are much more in evidence than in any other of his chief writings; and incidentally he also displays a curious insensibility—again characteristic of his period—to all that is specific in the religious attitude. But when due allowances have been made, we can still maintain that in resting his constructive views upon the supreme value of the moral personality Kant has influenced subsequent philosophy in hardly less degree than by his teaching in the Critique of Pure Reason.[63]

The two Critiques, in method of exposition and argument, in general outcome, and indeed in the total impression they leave upon the mind, are extraordinarily different. In the Critique of Pure Reason Kant is meticulously scrupulous in testing the validity of each link in his argument. Constantly he retraces his steps; and in many of his chief problems he halts between competing solutions. Kant’s sceptical spirit is awake, and it refuses to cease from its questionings. In the Critique of Practical Reason, on the other hand, there is an austere simplicity of argument, which advances, without looking to right or left, from a few simple principles direct to their ultimate consequences. The impressiveness of the first Critique consists in its appreciation of the complexity of the problems, and in the care with which their various, conflicting aspects are separately dealt with. The second Critique derives its force from the fundamental conviction upon which it is based.

Such, then, stated in the most general terms, is the manner in which Kant conceives the Critique of Pure Reason as contributing to the establishment of a humanistic philosophy. It clears the ground for the practical Reason, and secures it in the autonomous control of its own domain. While preserving to the intellect and to science certain definitely prescribed rights, Kant places in the forefront of his system the moral values; and he does so under the conviction that in living up to the opportunities, in whatever rank of life, of our common heritage, we obtain a truer and deeper insight into ultimate issues than can be acquired through the abstruse subtleties of metaphysical speculation.

I may again draw attention to the consequences which follow from Kant’s habitual method of isolating his problems. Truth is a value of universal jurisdiction, and from its criteria{lxi} the judgments of moral and other values can claim no exemption. Existences and values do not constitute independent orders. They interpenetrate, and neither can be adequately dealt with apart from the considerations appropriate to the other. In failing to co-ordinate his problems, Kant has over-emphasised the negative aspects of his logical enquiries and has formulated his ethical doctrines in a needlessly dogmatic form.

These defects are, however, in some degree remedied in the last of his chief works, the Critique of Judgment. In certain respects it is the most interesting of all Kant’s writings. The qualities of both the earlier Critiques here appear in happy combination, while in addition his concrete interests are more in evidence, to the great enrichment of his abstract argument. Many of the doctrines of the Critique of Pure Reason, especially those that bear on the problems of teleology, are restated in a less negative manner, and in their connection with the kindred problems of natural beauty and the fine arts. For though the final decision in all metaphysical questions is still reserved to moral considerations, Kant now takes a more catholic view of the field of philosophy. He allows, though with characteristic reservations, that the empirical evidence obtainable through examination of the broader features of our total experience is of genuinely philosophical value, and that it can safely be employed to amplify and confirm the independent convictions of the moral consciousness. The embargo which in the Critique of Pure Reason, in matters metaphysical, is placed upon all tentative and probable reasoning is thus tacitly removed; and the term knowledge again acquires the wider meaning very properly ascribed to it in ordinary speech.{1}



THE term critique or criticism, as employed by Kant, is of English origin. It appears in seventeenth and eighteenth century English, chiefly in adjectival form, as a literary and artistic term—for instance, in the works of Pope, who was Kant’s favourite English poet. Kant was the first to employ it in German, extending it from the field of aesthetics to that of general philosophy. A reference in Kant’s Logic[64] to Home’s Elements of Criticism[65] would seem to indicate that it was Home’s use of the term which suggested to him its wider employment. “Critique of pure reason,” in its primary meaning, signifies the passing of critical judgments upon pure reason. In this sense Kant speaks of his time as “the age of criticism (Zeitalter der Kritik).” Frequently, however, he takes the term more specifically as meaning a critical investigation leading to positive as well as to negative results. Occasionally, especially in the Dialectic, it also signifies a discipline applied to pure reason, limiting it within due bounds. The first appearance of the word in Kant’s writings is in 1765 in the Nachricht[66] of his lectures for the winter term 1765-1766. Kant seldom employs the corresponding adjective, critical (kritisch). His usual substitute for it is the term transcendental.

Pure (rein) has here a very definite meaning. It is the absolutely a priori. Negatively it signifies that which is{2} independent of experience. Positively it signifies that which originates from reason itself, and which is characterised by universality and necessity.[67] By “pure reason” Kant therefore means reason in so far as it supplies out of itself, independently of experience, a priori elements that as such are characterised by universality and necessity.

Reason (Vernunft) is used in the Critique in three different meanings. In the above title it is employed in its widest sense, as the source of all a priori elements. It includes what is a priori in sensibility as well as in understanding (Verstand). In its narrowest sense it is distinct even from understanding, and signifies that faculty which renders the mind dissatisfied with its ordinary and scientific knowledge, and which leads it to demand a completeness and unconditionedness which can never be found in the empirical sphere. Understanding conditions science; reason generates metaphysic. Understanding has categories; reason has its Ideas. Thirdly, Kant frequently employs understanding and reason as synonymous terms, dividing the mind only into the two faculties, sensibility and spontaneity. Thus in A 1-2, understanding and reason are used promiscuously, and in place of reine Vernunft we find reiner Verstand. As already stated, the term reason, as employed in Kant’s title, ought properly to be taken in its widest sense. Sensibility falls within reason in virtue of the a priori forms which it contains. Kant does not himself, however, always interpret the title in this strict sense. The triple use of the term is an excellent example of the looseness and carelessness with which he employs even the most important and fundamental of his technical terms. Only the context can reveal the particular meaning to be assigned in each case.

The phrase “of pure reason” (der reinen Vernunft) has, as Vaihinger points out,[68] a threefold ambiguity. (1) Sometimes it is a genitive objective. The critical enquiry is directed upon pure reason as its object. This corresponds to the view of the Critique as merely a treatise on method. (2) Sometimes it is a genitive subjective. The critical enquiry is undertaken by and executed through pure reason. This expresses the view of the Critique as itself a system of pure rational knowledge. (3) At other times it has a reflexive meaning. Pure reason is subject and object at once. It is both subject-matter and method or instrument. Through the Critique it attains to self-knowledge. The Critique is the critical examination of pure reason by itself. The first view{3} would seem to be the original and primary meaning of the title. The second view very early took its place alongside it, and appears in many passages. The third view must be taken as representing Kant’s final interpretation of the title; it is on the whole the most adequate to the actual content and scope of the Critique. For the Critique is not merely a treatise on method; it is also a system of pure rational knowledge. It professes to establish, in an exhaustive and final manner, the a priori principles which determine the possibility, conditions, and limits of pure rational knowledge.[69]



DE nobis ipsis silemus: De re autem, quae agitur, petimus: ut homines eam non opinionem, sed opus esse cogitent; ac pro certo habeant, non sectae nos alicuius, aut placiti, sed utilitatis et amplitudinis humanae fundamenta moliri. Deinde ut suis commodis aequi ... in commune consulant ... et ipsi in partem veniant. Praeterea ut bene sperent, neque instaurationem nostram ut quiddam infinitum et ultra mortale fingant, et animo concipiant; quum revera sit infiniti erroris finis et terminus legitimus.

This motto, which was added in the second edition, is taken from the preface to Bacon’s Instauratio Magna, of which the Novum Organum is the second part. As the first part of the Instauratio is represented only by the later, separately published, De Augmentis Scientiarum, this preface originally appeared, and is still usually given, as introductory to the Novum Organum.

The complete passage (in which I have indicated Kant’s omissions) is rendered as follows in the translation of Ellis and Spedding:[70]

“Of myself I say nothing; but in behalf of the business which is in hand I entreat men to believe that it is not an opinion to be held, but a work to be done; and to be well assured that I am labouring to lay the foundation, not of any sect or doctrine, but of human utility and power. Next, I ask them to deal fairly by their own interests [and laying aside all emulations and prejudices in favour of this or that opinion], to join in consultation for the common good; and [being now freed and guarded by the securities and helps which I offer from the errors and impediments of the way] to come forward themselves and take part [in that which remains to be done]. Moreover, to be of good hope, nor to imagine that this Instauration of mine is a thing infinite and beyond the power of man, when it is in fact the true end and termination of infinite error.”


The opening sentence of Bacon’s preface might also have served as a fitting motto to the Critique:

“It seems to me that men do not rightly understand either their store or their strength, but overrate the one and underrate the other.”

Or again the following:

“I have not sought nor do I seek either to enforce or to ensnare men’s judgments, but I lead them to things themselves and the concordances of things, that they may see for themselves what they have, what they can dispute, what they can add and contribute to the common stock.... And by these means I suppose that I have established for ever a true and lawful marriage between the empirical and the rational faculty, the unkind and ill-starred divorce and separation of which has thrown into confusion all the affairs of the human family.”





Karl Abraham, Freiherr von Zedlitz had been entrusted, as Minister (1771-1788) to Frederick the Great, with the oversight and direction of the Prussian system of education. He held Kant in the highest esteem.[71] In February 1778 we find him writing to thank Kant for the pleasure he had found in perusing notes of his lectures on physical geography, and requesting the favour of a complete copy.[72] A week later he invited Kant to accept a professorship of philosophy in Halle,[73] which was then much the most important university centre in Germany. Upon Kant’s refusal he repeated the offer, with added inducements, including the title of Hofrat.[74] Again, in August of the same year, he writes that he is attending, upon Mendelssohn’s recommendation (and doubtless also in the hope of receiving from this indirect source further light upon Kant’s own teaching in a favourite field), the lectures on anthropology of Kant’s disciple and friend, Marcus Herz. The letter concludes with a passage which may perhaps have suggested to Kant the appropriateness of dedicating his Critique to so wise and discerning a patron of true philosophy.

“Should your inventive power extend so far, suggest to me the means of holding back the students in the universities from the bread and butter studies, and of making them understand that their modicum of law, even their theology and medicine, will be immensely{7} more easily acquired and safely applied, if they are in possession of more philosophical knowledge. They can be judges, advocates, preachers and physicians only for a few hours each day; but in these and all the remainder of the day they are men, and have need of other sciences. In short, you must instruct me how this is to be brought home to students. Printed injunctions, laws, regulations—these are even worse than bread and butter study itself.”[75]

A Minister of Education who thus ranks philosophy above professional studies, and both as more important than all academic machinery, holds his office by divine right.{8}


Detailed discussion of the Prefaces is not advisable. The problems which they raise can best be treated in the order in which they come up in the Critique itself. I shall dwell only on the minor incidental difficulties of the text, and on those features in Kant’s exposition which are peculiar to the Prefaces, or which seem helpful in the way of preliminary orientation. I shall first briefly restate the argument of the Preface to the first edition, and then add the necessary comment.

Human reason is ineradicably metaphysical. It is haunted by questions which, though springing from its very nature, none the less transcend its powers. Such a principle, for instance, as that of causality, in carrying us to more and more remote conditions, forces us to realise that by such regress our questions can never be answered. However far we recede in time, and however far we proceed in space, we are still no nearer to a final answer to our initial problems, and are therefore compelled to take refuge in postulates of a different kind, such, for instance, as that there must be a first unconditioned cause from which the empirical series of causes and effects starts, or that space is capable of existing as a completed whole. But these assumptions plunge reason in darkness and involve it in contradictions. They are the sources of all the troubles of the warring schools. Error lies somewhere concealed in them—the more thoroughly concealed that they surpass the limits of possible experience. Until such error has been detected and laid bare, metaphysical speculation must remain the idlest of all tasks.

In the latter part of the eighteenth century metaphysics had fallen, as Kant here states, into disrepute. The wonderful success with which the mathematical and natural sciences were being developed served only to emphasise by contrast the ineffectiveness of the metaphysical disciplines. Indifference to philosophy was the inevitable outcome, and was due, not to levity, but to the matured judgment of the age, which refused to be any longer put off with such pretended{9} knowledge. But since the philosophical sciences aim at that knowledge which, if attainable, we should be least willing to dispense with, the failure of philosophy is really a summons to reason to take up anew the most difficult of all its tasks. It must once and for all determine either the possibility or the impossibility of metaphysics. It must establish

“...a tribunal which will assure to reason its lawful claims, and which will also be able to dismiss all groundless pretensions, not by despotic decrees, but in accordance with its own eternal and unalterable laws. This tribunal is no other than the Critique of Pure Reason.”[76] “Our age is, in especial degree, the age of criticism (Kritik), and to such criticism everything must submit. Religion, through its sanctity, and law-giving, through its majesty, may seek to exempt themselves from it. But they then awaken just suspicion, and cannot claim the sincere respect which reason accords only to that which has been able to sustain the test of free and open examination.”[77]

As has already been emphasised in the preceding historical sketch, Kant had learnt to trust the use of reason, and was a rationalist by education, temperament, and conviction. He here classifies philosophies as dogmatic and sceptical; and under the latter rubric he includes all empirical systems. ‘Empiricism’ and ‘scepticism’ he interprets as practically synonymous terms. The defect of the dogmatists is that they have not critically examined their methods of procedure, and in the absence of an adequate distinction between appearance and reality have interpreted the latter in terms of the former. The defect of the empiricists and sceptics is that they have misrepresented the nature of the faculty of reason, ignoring its claims and misreading its functions, and accordingly have gone even further astray than their dogmatic opponents. All knowledge worthy of the name is a priori knowledge. It possesses universality and necessity, and as such must rest on pure reason. Wherever there is science, there is an element of pure reason. Whether or not pure reason can also extend to the unconditioned is the question which decides the possibility of constructive metaphysics. This is what Kant means when he declares that the Critique is a criticism of the power of reason, in respect of all knowledge after which it may strive independently of experience. Pure reason is the subject-matter of the enquiry; it is also the instrument through which the enquiry is made.[78] Nothing empirical or merely hypothetical has any place in it, either as subject-matter or as method of argument.

From this position Kant draws several important consequences.{10} First, since pure reason means that faculty whereby we gain knowledge independently of all experience, it can be isolated and its whole nature exhaustively determined. Indeed pure reason (Kant seeks to prove) is so perfect a unity that if “its principle” should be found insufficient to the solution of a single one of all the questions which are presented to it by its own nature, we should be justified in forthwith rejecting it as also incompetent to answer with complete certainty any one of the other questions. In metaphysics it must be either all or nothing,[79] either final and complete certainty or else absolute failure.

“While I am saying this I can fancy that I detect in the face of the reader an expression of indignation mingled with contempt at pretensions seemingly so arrogant and vainglorious; and yet they are incomparably more moderate than the claims of all those writers who on the lines of the usual programme profess to prove the simple nature of the soul or the necessity of a first beginning of the world.”[80]

In so doing they pretend to define realities which lie beyond the limits of possible experience; the Critique seeks only to deal with that faculty of reason which manifests itself to us within our own minds. Formal logic shows how completely and systematically the simple acts of reason can be enumerated. Aristotle created this science of logic complete at a stroke. Kant professes to have established an equally final metaphysics; and as logic is not a science proper, but rather a propaedeutic to all science, metaphysics, thus interpreted, is the only one of all the sciences which can immediately attain to such completeness.

“For it is nothing but the inventory of all our possessions through pure reason, systematically arranged. In this field nothing can escape us. What reason produces entirely out of itself cannot lie concealed, but is brought to light by reason itself immediately the common principle has been discovered.”[81]

Secondly, the Critique also claims certainty. With the removal of everything empirical, and the reduction of its subject-matter to pure reason, all mere opinion or hypothesis is likewise eliminated. Probabilities or hypotheses can have no place in a Critique of Pure Reason.[82] Everything must be derived according to a priori principles from pure conceptions in which there is no intermixture of experience or any special intuition.


This Preface to the first edition, considered as introductory{11} to the Critique, is misleading for two reasons. First, because in it Kant is preoccupied almost exclusively with the problems of metaphysics in the strict ontological sense, that is to say, with the problems of the Dialectic. The problems of the Analytic, which is the very heart of the Critique, are almost entirely ignored. They are, it is true, referred to in A x-xi, but the citation is quite externally intercalated; it receives no support or extension from the other parts of the Preface. This results in a second defect, namely, that Kant fails to indicate the more empirical features of his new Critical standpoint. Since ultimate reality is supersensuous, metaphysics, as above conceived, can have no instrument save pure reason. The subjects of its enquiry, God, freedom, and immortality, if they are to be known at all, can be determined only through a priori speculation. This fact, fundamental and all-important for Kant, was completely ignored in the popular eclectic philosophies of the time. They professed to derive metaphysical conclusions from empirical evidence. They substituted, as Kant has pointed out,[83] “a physiology of the human understanding” for the Critical investigation of the claims of reason, and anthropology for ethics. They were blind to the dogmatism of which they are thereby guilty. They assumed those very points which most call for proof, namely, that reason is adequate to the solution of metaphysical problems, and that all existence is so fundamentally of one type that we can argue from the sensuous to the supersensuous, from appearance to reality. When they fell into difficulties, they pleaded the insufficiency of human reason, and yet were all the while unquestioningly relying upon it in the drawing of the most tremendous inferences. Such, for instance, are the assumptions which underlie Moses Mendelssohn’s contention that since animals as well as men agree in the apprehension of space, it must be believed to be absolutely real.[84] These assumptions also determine Priestley’s assertion that though every event has its cause, there is one causeless happening, namely, the creative act to which the existence of the world is due.[85] On such terms, metaphysics is too patently easy to be even plausible. “Indifference, doubt, and, in final issue, severe criticism, are truer signs of a profound habit of thought.”[86] The matter of experience affords no data for metaphysical inference. In the a priori forms of experience, and there alone, can metaphysics{12} hope to find a basis, if any basis is really discoverable.

This is Kant’s reason for so emphatically insisting that the problem of the Critique is to determine “how much we can hope to achieve by reason, when all the material and assistance of experience is taken away.”[87] But in keeping only this one point in view Kant greatly misrepresents the problems and scope of the Critique. Throughout the Preface he speaks the language of the Aufklärung. Even in the very act of limiting the scope of reason, he overstresses its powers, and omits reference to its empirical conditions. It is well to contrast this teaching with such a passage as the following:

“The position of all genuine idealists from the Eleatics to Berkeley is contained in this formula: ‘All cognition through the senses and experience is nothing but mere illusion, and only in the ideas of pure understanding and Reason is there truth.’ The fundamental principle ruling all my idealism, on the contrary, is this: ‘All cognition of things solely from pure understanding or pure Reason is nothing but mere illusion, and only in experience is there truth.’”[88]

But that passage is equally inadequate as a complete expression of Kant’s Critical philosophy. The truth lies midway between it and the teaching of the Preface to the first edition. Pure reason is as defective an instrument of knowledge as is factual experience. Though the primary aim of metaphysics is to determine our relation to the absolutely real, and though that can only be done by first determining the nature and possible scope of a priori principles, such principles are found on investigation to possess only empirical validity. The central question of the Critique thus becomes the problem of the validity of their empirical employment. The interrelation of these two problems, that of the a priori and that of experience, and Kant’s attitude towards them, cannot be considered till later. The defects of the Preface to the first edition are in part corrected by the extremely valuable Preface substituted in the second edition. But some further points in this first Preface must be considered.

Prescribed by the very nature of reason itself.[89]—Metaphysics exists as a “natural disposition,” and its questions are not therefore merely artificial.

“As natural disposition (Naturanlage) ... metaphysics is real. For human reason, without being moved merely by the idle desire for extent and variety of knowledge, proceeds impetuously, driven on by{13} an inward need, to questions such as cannot be answered by any empirical employment of reason, or by principles thence derived. Thus in all men, as soon as their reason has become ripe for speculation, there has always existed and will always continue to exist some kind of metaphysics.”[90]

Hence results what Kant entitles transcendental illusion.

“The cause of this transcendental illusion is that there are fundamental rules and maxims for the employment of Reason, subjectively regarded as a faculty of human knowledge, and that these rules and maxims have all the appearance of being objective principles. We take the subjective necessity of a connection of our concepts, i.e. a connection necessitated for the advantage of the understanding, for an objective necessity in the determination of things in themselves. This is an illusion which can no more be prevented than we can prevent the sea from appearing higher at the horizon than at the shore, since we see it through higher light rays; or to cite a still better example, than the astronomer can prevent the moon from appearing larger at its rising, although he is not deceived by this illusion.... There exists, then, a natural and unavoidable dialectic of pure Reason, not one in which a bungler might entangle himself through lack of knowledge, or one which some sophist has artificially invented to confuse thinking people, but one which is inseparable from human Reason, and which, even after its deceiving power has been exposed, will not cease to play tricks with it and continually to entrap it into momentary aberrations that will ever and again call for correction.”[91]

Dogmatism.[92]—According to Kant there are three possible standpoints in philosophy—the dogmatic, the sceptical, and the critical. All preceding thinkers come under the first two heads. A dogmatist is one who assumes that human reason can comprehend ultimate reality, and who proceeds upon this assumption. He does not, before proceeding to construct a metaphysics, enquire whether it is possible. Dogmatism expresses itself (to borrow Vaihinger’s convenient mode of definition[93]) through three factors—rationalism, realism, and transcendence. Descartes and Leibniz are typical dogmatists. As rationalists they hold that it is possible to determine from pure a priori principles the ultimate nature of God, of the soul, and of the material universe. They are realists in that they assert that by human thought the complete nature of objective reality can be determined. They also adopt the attitude of transcendence. Through pure thought they go out beyond the sensible and determine the supersensuous.{14} Scepticism (Kant, as above stated,[94] regards it as being in effect equivalent to empiricism) may similarly be defined through the three terms, empiricism, subjectivism, immanence. A sceptic can never be a rationalist. He must reduce knowledge to sense-experience. For this reason also his knowledge is infected by subjective conditions; through sensation we cannot hope to determine the nature of the objectively real. This attitude is also that of immanence; knowledge is limited to the sphere of sense-experience. Criticism has similarly its three constitutive factors, rationalism, subjectivism, immanence. It agrees with dogmatism in maintaining that only through a priori principles can true knowledge be obtained. Such knowledge is, however, subjective[95] in its origin, and for that reason it is also only of immanent application; knowledge is possible only in the sphere of sense-experience. Dogmatism claims that knowledge arises independently of experience and extends beyond it. Empiricism holds that knowledge arises out of sense-experience and is valid only within it. Criticism teaches that knowledge arises independently of particular experience but is valid only for experience.

The following passages in the Methodology give Kant’s view of the historical and relative values of the two false methods:

“The sceptic is the taskmaster who constrains the dogmatic reasoner to develop a sound critique of the understanding and reason. When the latter has been made to advance thus far, he need fear no further challenge, since he has learned to distinguish his real possessions from that which lies entirely beyond them, and to which he can therefore lay no claim.... Thus the sceptical procedure cannot of itself yield any satisfying answer to the questions of reason, but none the less it prepares the way by awakening its circumspection, and by indicating the radical measures which are adequate to secure it in its legitimate possessions.”[96] “The first step in matters of pure reason, marking its infancy, is dogmatic. The second step is sceptical, and indicates that experience has rendered our judgment wiser and more circumspect. But a third step, such as can be taken only by fully matured judgment, is now necessary.... This is not the censorship but the critique of reason, whereby not its present bounds but its determinate [and necessary] limits, not its ignorance on this or that point, but in regard to{15} all possible questions of a certain kind, are demonstrated from principles, and not merely arrived at by way of conjecture. Scepticism is thus a resting-place for human reason, where it can reflect upon its dogmatic wanderings and make survey of the region in which it finds itself, so that for the future it may be able to choose its path with more certainty. But it is no dwelling-place for permanent settlement. That can be obtained only through perfect certainty in our knowledge, alike of the objects themselves and of the limits within which all our knowledge of objects is enclosed.”[97]

Locke.[98]—Cf. A 86 = B 119; A 270 = B 327; B 127.

On the unfavourable contrast between mathematics and metaphysics.[99]—Cf. Ueber die Deutlichkeit der Grundsätze (1764), erste Betrachtung, and below, pp. 40, 563 ff.

The age of criticism.[100]—Kant considered himself as contributing to the further advance of the eighteenth century Enlightenment.[101] In view, however, of the contrast between eighteenth and nineteenth century thought, and of the real affiliations and ultimate consequences of Kant’s teaching, it seems truer to regard the Critical philosophy as at once completing and transcending the Aufklärung. Kant breaks with many of its most fundamental assumptions.

The Critique of Pure Reason.[102]—Kant here defines the Critique as directed upon pure reason.[103] Further, it is a criticism of knowledge which is “independent of all experience,” or, as Kant adds “free from all experience.” Such phrases, in this context, really mean transcendent. The Critique is here taken as being a Critical investigation of transcendent metaphysics, of its sources, scope, and limits.[104]

Opinion or hypothesis not permissible.[105]—Cf. below, p. 543 ff.

I know no enquiries, etc.[106]—The important questions raised by this paragraph are discussed below, p. 235 ff.

Jean Terrasson (1670-1750).[107]—The quotation is from his work posthumously published (1754), and translated from the French by Frau Gottsched under the title Philosophie nach ihrem allgemeinen Einflusse auf alle Gegenstände des Geistes und der Sitten (1762). Terrasson is also referred to by Kant in his Anthropologie, §§ 44 and 77. Terrasson would seem to be the author of the Traité de l’infini créé which has been falsely ascribed to Malebranche. I have translated this latter treatise in the Philosophical Review (July 1905).

Such a system of pure speculative reason.[108]—The relation in{16} which this system would stand to the Critique is discussed below, pp. 71-2. Speculative does not with Kant mean transcendent, but merely theoretical as opposed to practical. Cf. B 25, A 15 = B 29, A 845 = B 873.

Under the title: Metaphysics of Nature.[109]—No such work, at least under this title, was ever completed by Kant. In the Kantian terminology “nature” signifies “all that is.” Cf. below, p. 580.{17}


I SHALL again give a brief explanatory paraphrase, before proceeding to detailed comment. The main points of the preface of the first edition are repeated. “Metaphysics soars above all teaching of experience, and rests on concepts only. In it reason has to be her own pupil.”[110] But Kant immediately proceeds to a further point. That logic should have attained the secure method of science is due to its limitation to the mere a priori form of knowledge. For metaphysics this is far more difficult, since it “has to deal not with itself alone, but also with objects.”[111]

The words which I have italicised form a very necessary correction of the first edition preface, according to which the Critique would seem to “treat only of reason and its pure thinking.” A further difference follows. The second edition preface, in thus emphasising the objective aspect of the problem, is led to characterise in a more complete manner the method to be followed in the Critical enquiry. How can the Critique, if it is concerned, as both editions agree in insisting, only with the a priori which originates in human reason, solve the specifically metaphysical problem, viz. that of determining the independently real? How can an idea in us refer to, and constitute knowledge of, an object? The larger part of the preface to the second edition is devoted to the Critical solution of this problem. The argument of the Dialectic is no longer emphasised at the expense of the Analytic.

Kant points out that as a matter of historical fact each of the two rational sciences, mathematics and physics, first entered upon the assured path of knowledge by a sudden revolution, and by the adoption of a method which in its general characteristics is common to both. This method consists, not in being led by nature as in leading-strings, but in interrogating nature in accordance with what reason{18} produces on its own plan. The method of the geometrician does not consist in the study of figures presented to the senses. That would be an empirical (in Kant’s view, sceptical) method. Geometrical propositions could not then be regarded as possessing universality and necessity. Nor does the geometrician employ a dogmatic method, that of studying the mere conception of a figure. By that means no new knowledge could ever be attained. The actual method consists in interpreting the sensible figures through conceptions that have been rigorously defined, and in accordance with which the figures have been constructively generated. The first discovery of this method, by Thales or some other Greek, was “far more important than the discovery of the passage round the celebrated Cape of Good Hope.”[112]

Some two thousand years elapsed before Galileo formulated a corresponding method for physical science. He relied neither on mere observation nor on his own conceptions. He determined the principles according to which alone concordant phenomena can be admitted as laws of nature, and then by experiment compelled nature to answer the questions which these principles suggest. Here again the method is neither merely empirical nor purely dogmatic. It possesses the advantages of both.

Metaphysics is ripe for a similar advance. It must be promoted to the rank of positive science by the transforming power of an analogous method. The fundamental and distinguishing characteristic of mathematical and physical procedure is the legislative power to which reason lays claim. Such procedure, if generalised and extended, will supply the required method of the new philosophy. Reason must be regarded as self-legislative in all the domains of our possible knowledge. Objects must be viewed as conforming to human thought, not human thought to the independently real. This is the “hypothesis” to which Kant has given the somewhat misleading title, “Copernican.”[113] The method of procedure which it prescribes is, he declares, analogous to that which was followed by Copernicus, and will be found to be as revolutionary in its consequences. In terms of this hypothesis a complete and absolutely certain metaphysics, valid now and for all time, can be created at a stroke. The earliest and oldest enterprise of the human mind will achieve a new beginning. Metaphysics, the mother of all the sciences, will renew her youth, and will equal in assurance, as she surpasses in dignity, the offspring of her womb.

From this new standpoint Kant develops phenomenalism{19} on rationalist lines. He professes to prove that though our knowledge is only of appearances, it is conditioned by a priori principles. His “Copernican hypothesis,” so far from destroying positive science, is, he claims, merely a philosophical extension of the method which it has long been practising. Since all science worthy of the name involves a priori elements, it can be accounted for only in terms of the new hypothesis. Only if objects are regarded as conforming to our forms of intuition, and to our modes of conception, can they be anticipated by a priori reasoning. Science can be a priori just because, properly understood, it is not a rival of metaphysics, and does not attempt to define the absolutely real.

But such a statement at once suggests what may at first seem a most fatal objection. Though the new standpoint may account for the a priori in experience and science, it can be of no avail in metaphysics. If the a priori concepts have a mental origin, they can have no validity for the independently real. If we can know only what we ourselves originate, things in themselves must be unknown, and metaphysics must be impossible. But in this very consequence the new hypothesis first reveals its full advantages. It leads to an interpretation of metaphysics which is as new and as revolutionary[114] as that which it gives to natural science. Transcendent metaphysics is indeed impossible, but in harmony with man’s practical and moral vocation, its place is more efficiently taken by an immanent metaphysics on the one hand, and by a metaphysics of ethics on the other. Together these constitute the new and final philosophy which Kant claims to have established by his Critical method. Its chief task is to continue “that noblest enterprise of antiquity,”[115] the distinguishing of appearances from things in themselves. The unconditioned is that which alone will satisfy speculative reason; its determination is the ultimate presupposition of metaphysical enquiry. But so long as the empirical world is regarded as true reality, totality or unconditionedness cannot possibly be conceived—is, indeed, inherently self-contradictory. On the new hypothesis there is no such difficulty. By the proof that things in themselves are unknowable, a sphere is left open within which the unconditioned can be sought. For though this sphere is closed to speculative reason, the unconditioned can be determined from data yielded by reason in its practical activity. The hypothesis which at first seems to destroy metaphysics proves on examination to be its necessary presupposition. The “Copernican hypothesis” which conditions science will also account for metaphysics properly conceived.{20}

Upon this important point Kant dwells at some length. Even the negative results of the Critique are, he emphasises, truly positive in their ultimate consequences. The dogmatic extension of speculative reason really leads to the narrowing of its employment, for the principles of which it then makes use involve the subjecting of things in themselves to the limiting conditions of sensibility. All attempts to construe the unconditioned in terms that will satisfy reason are by such procedure ruled out from the very start. To demonstrate this is the fundamental purpose and chief aim of the Critique. Space and time are merely forms of sensuous intuition; the concepts of understanding can yield knowledge only in their connection with them. Though the concepts in their purity possess a quite general meaning, this is not sufficient to constitute knowledge. The conception of causality, for instance, necessarily involves the notion of time-sequence; apart from time it is the bare, empty, and entirely unspecified conception of a sufficient ground. Similarly, the category of substance signifies the permanent in time and space; as a form of pure reason it has a quite indefinite meaning signifying merely that which is always a subject and never a predicate. In the absence of further specification, it remains entirely problematic in its reference. The fact, however, that the categories of the understanding possess, in independence of sensibility, even this quite general significance is all-important. Originating in pure reason they have a wider scope than the forms of sense, and enable us to conceive, though not to gain knowledge of, things in themselves.[116] Our dual nature, as being at once sensuous and supersensuous, opens out to us the apprehension of both.

Kant illustrates his position by reference to the problem of the freedom of the will. As thought is wider than sense, and reveals to us the existence of a noumenal realm, we are enabled to reconcile belief in the freedom of the will with the mechanism of nature. We can recognise that within the phenomenal sphere everything without exception is causally determined, and yet at the same time maintain that the whole order of nature is grounded in noumenal conditions. We can assert of one and the same being that its will is subject to the necessity of nature and that it is free—mechanically determined in its visible actions, free in its real supersensible existence. We have, indeed, no knowledge of the soul, and therefore cannot assert on theoretical grounds that it possesses any such freedom. The very possibility of freedom transcends our powers of comprehension. The{21} proof that it can at least be conceived without contradiction is, however, all-important. For otherwise no arguments from the nature of the moral consciousness could be of the least avail; before a palpable contradiction every argument is bound to give way. Now, for the first time, the doctrine of morals and the doctrine of nature can be independently developed, without conflict, each in accordance with its own laws. The same is true in regard to the existence of God and the immortality of the soul. By means of the Critical distinction between the empirical and the supersensible worlds, these conceptions are now for the first time rendered possible of belief. “I had to remove knowledge, in order to make room for belief.”[117] “This loss affects only the monopoly of the schools, in no respect the interests of humanity.”[118]

Lastly, Kant emphasises the fact that the method of the Critique must be akin to that of dogmatism. It must be rational a priori. To adopt any other method of procedure is “to shake off the fetters of science altogether, and thus to change work into play, certainty into opinion, philosophy into philodoxy.”[119] And Kant repeats the claims of the preface of the first edition as to the completeness and finality of his system. “This system will, as I hope, maintain through the future this same unchangeableness.”[120]

Logic.[121]—For Kant’s view of the logic of Aristotle as complete and perfect, cf. below, pp. 184-5. Kant compares metaphysics to mathematics and physics on the one hand, and to formal logic on the other. The former show the possibility of attaining to the secure path of science by a sudden and single revolution; the latter demonstrates the possibility of creating a science complete and entire at a stroke. Thanks to the new Critical method, metaphysics may be enabled, Kant claims, to parallel both achievements at once.

Theoretical and practical reason.[122]—Such comment as is necessary upon this distinction is given below. Cf. p. 569 ff.

Hitherto it has been supposed that all knowledge must conform to the objects.[123]—This statement is historically correct. That assumption did actually underlie one and all of the pre-Kantian philosophies. At the same time, it is true that Kant’s phenomenalist standpoint is partially anticipated by Hume, by Malebranche and by Leibniz, especially by the first named. Hume argues that to condemn knowledge on the ground that it can never copy or truly reveal any external reality is to misunderstand its true function. Our sense perceptions and our general principles are so determined by nature{22} as to render feasible only a practical organisation of life. When we attempt to derive from them a consistent body of knowledge, failure is the inevitable result.[124] Malebranche, while retaining the absolutist view of conceptual knowledge, propounds a similar theory of sense-perception.[125] Our perceptions are, as he shows, permeated through and through, from end to end, with illusion. Such illusions justify themselves by their practical usefulness, but they likewise prove that theoretical insight is not the purpose of our sense-experience. Kant’s Copernican hypothesis consists in great part of an extension of this view to our conceptual, scientific knowledge. But he differs both from Malebranche and from Hume in that he develops his phenomenalism on rationalist lines. He professes to show that though our knowledge is only of the phenomenal, it is conditioned by a priori principles. The resulting view of the distinction between appearance and reality has kinship with that of Leibniz.[126] The phenomena of science, though only appearances, are none the less bene fundata. Our scientific knowledge, though not equivalent to metaphysical apprehension of the ultimately real, can be progressively developed by scientific methods.

The two “parts” of metaphysics.[127]—Kant is here drawing the important distinction, which is one result of his new standpoint, between immanent and transcendent metaphysics. It is unfortunate that he does not do so in a more explicit manner, with full recognition of its novelty and of its far-reaching significance. Many ambiguities in his exposition here and elsewhere would then have been obviated.[128]

The unconditioned which Reason postulates in all things by themselves, by necessity and by right.[129]—Points are here raised the discussion of which must be deferred. Cf. below, pp. 429-31, 433-4, 558-61.

The Critique is a treatise on method, not a system of the science itself.[130]—Cf. A xv.; B xxxvi.; and especially A 11 = B 24, below pp. 71-2.

The Copernican hypothesis.[131]—Kant’s comparison of his new hypothesis to that of Copernicus has generally been misunderstood. The reader very naturally conceives the Copernican revolution in terms of its main ultimate consequence, the reduction of the earth from its proud position of central pre-eminence. But that does not bear the least{23} analogy to the intended consequences of the Critical philosophy. The direct opposite is indeed true. Kant’s hypothesis is inspired by the avowed purpose of neutralising the naturalistic implications of the Copernican astronomy. His aim is nothing less than the firm establishment of what may perhaps be described as a Ptolemaic, anthropocentric metaphysics. Such naturalistic philosophy as that of Hume may perhaps be described as Copernican, but the Critical philosophy, as humanistic, has genuine kinship with the Greek standpoint.

Even some of Kant’s best commentators have interpreted the analogy in the above manner.[132] It is so interpreted by T. H. Green[133] and by J. Hutchison Stirling.[134] Caird in his Critical Philosophy of Kant makes not the least mention of the analogy, probably for the reason that while reading it in the same fashion as Green, he recognised the inappropriateness of the comparison as thus taken. The analogy is stated in typically ambiguous fashion by Lange[135] and by Höffding.[136] S. Alexander, while very forcibly insisting upon the Ptolemaic character of the Kantian philosophy, also endorses this interpretation in the following terms:

“It is very ironical that Kant himself signalised the revolution which he believed himself to be effecting as a Copernican revolution. But there is nothing Copernican in it except that he believed it to be a revolution. If every change is Copernican which reverses the order of the terms with which it deals, which declares A to depend on B when B had before been declared to depend on A, then Kant—who believed that he had reversed the order of dependence of mind and things—was right in saying that he effected a Copernican revolution. But he was not right in any other sense. For his revolution, so far as it was one, was accurately anti-Copernican.”[137]

As the second edition preface is not covered by the published volumes of Vaihinger’s Commentary, the point has not been taken up by him.

Now Kant’s own statements are entirely unambiguous and do not justify any such interpretation as that of Green and Alexander. As it seems to me, they have missed the real point of the analogy. The misunderstanding would never have been possible save for our neglect of the scientific{24} classics. Kant must have had first-hand acquaintance with Copernicus’ De Revolutionibus, and the comparison which he draws assumes similar knowledge on the part of his readers. Copernicus by his proof of the “hypothesis” (his own term) of the earth’s motion sought only to achieve a more harmonious ordering of the Ptolemaic universe. And as thus merely a simplification of the traditional cosmology, his treatise could fittingly be dedicated to the reigning Pope. The sun upon which our terrestrial life depends was still regarded as uniquely distinct from the fixed stars; and our earth was still located in the central region of a universe that was conceived in the traditional manner as being single and spherical. Giordano Bruno was the first, a generation later, to realise the revolutionary consequences to which the new teaching, consistently developed, must inevitably lead. It was he who first taught what we have now come to regard as an integral part of Copernicus’ revolution, the doctrine of innumerable planetary systems side by side with one another in infinite space.

Copernicus’ argument starts from the Aristotelian principle of relative motion. To quote Copernicus’ exact words:

“All apprehended change of place is due to movement either of the observed object or of the observer, or to differences in movements that are occurring simultaneously in both. For if the observed object and the observer are moving in the same direction with equal velocity, no motion can be detected. Now it is from the earth that we visually apprehend the revolution of the heavens. If, then, any movement is ascribed to the earth, that motion will generate the appearance of itself in all things which are external to it, though as occurring in the opposite direction, as if everything were passing across the earth. This will be especially true of the daily revolution. For it seems to seize upon the whole world, and indeed upon everything that is around the earth, though not upon the earth itself.... As the heavens, which contain and cover everything, are the common locus of things, it is not at all evident why it should be to the containing rather than to the contained, to the located rather than to the locating, that a motion is to be ascribed.”[138]

The apparently objective movements of the fixed stars and of the sun are mere appearances, due to the projection of our own motion into the heavens.

“The first and highest of all the spheres is that of the fixed stars, self-containing and all-containing, and consequently immobile, in short the locus of the universe, by relation to which the motion and position of all the other heavenly bodies have to be reckoned.”[139]


Now it is this doctrine, and this doctrine alone, to which Kant is referring in the passages before us, namely, Copernicus’ hypothesis of a subjective explanation of apparently objective motions. And further, in thus comparing his Critical procedure to that of Copernicus, he is concerned more with the positive than with the negative consequences of their common hypothesis. For it is chiefly from the point of view of the constructive parts of the Aesthetic, Analytic, and Dialectic that the comparison is formulated. By means of the Critical hypothesis Kant professes on the one hand to account for our scientific knowledge, and on the other to safeguard our legitimate metaphysical aspirations. The spectator projects his own motion into the heavens; human reason legislates for the domain of natural science. The sphere of the fixed stars is proved to be motionless; things in themselves are freed from the limitations of space and time. “Copernicus dared, in a manner contradictory of the senses but yet true, to seek the observed movements, not in the heavenly bodies, but in the spectator.”[140]

In view of Kant’s explicit elimination of all hypotheses from the Critique[141] the employment of that term would seem to be illegitimate. He accordingly here states that though in the Preface his Critical theory is formulated as an hypothesis only, in the Critique itself its truth is demonstrated a priori.


Distinction between knowing and thinking.[142]—Since according to Critical teaching the limits of sense-experience are the limits of knowledge, the term knowledge has for Kant a very limited denotation, and leaves open a proportionately wide field for what he entitles thought. Though things in themselves are unknowable, their existence may still be recognised in thought.{26}


I SHALL first[143] give a restatement, partly historical and partly explanatory, of Kant’s main argument as contained in the enlarged Introduction of the second edition.

There were two stages in the process by which Kant came to full realisation of the Critical problem. There is first the problem as formulated in his letter of 1772 to Herz: how the a priori can yield knowledge of the independently real.[144] This, as he there states it, is an essentially metaphysical problem. It is the problem of the possibility of transcendent metaphysics. He became aware of it when reflecting upon the function which he had ascribed to intellect in the Dissertation. Then, secondly, this problem was immeasurably deepened, and at the same time the proper line for its treatment was discovered, through the renewed influence which Hume at some date subsequent to February 1772 exercised upon Kant’s thought.[145] Hume awakened Kant to what may be called the immanent problem involved in the very conception of a priori knowledge as such. The primary problem to be solved is not how we advance by means of a priori ideas to the independently real, but how we are able to advance beyond a subject term to a predicate which it does not appear to contain. The problem is indeed capable of solution, just because it takes this logical form. Here as elsewhere, ontological questions are viewed by Kant as soluble only to the extent to which they can be restated in logical terms. Now also the enquiry becomes twofold: how and in what degree are a priori synthetic judgments possible, first in their employment within the empirical sphere (the problem of immanent metaphysics) and secondly in their application to things in themselves (the problem of transcendent metaphysics). The outcome of the Critical enquiry is to establish{27} the legitimacy of immanent metaphysics and the impossibility of all transcendent speculation.

The argument of Kant’s Introduction follows the above sequence. It starts by defining the problem of metaphysical knowledge a priori, and through it leads up to the logical problem of the a priori synthetic judgment. In respect of time all knowledge begins with experience. But it does not therefore follow that it all arises from experience. Our experience may be a compound of that which we receive through impressions, and of that which pure reason supplies from itself.[146] The question as to whether or not any such a priori actually exists, is one that can be answered only after further enquiry. The two inseparable criteria of the a priori are necessity and universality. That neither can be imparted to a proposition by experience was Kant’s confirmed and unquestioned belief. He inherited this view both from Leibniz and from Hume. It is one of the presuppositions of his argument. Experience can reveal only co-existence or sequence. It enables us only to assert that so far as we have hitherto observed, there is no exception to this or that rule. A generalisation, based on observation, can never possess a wider universality than the limited experience for which it stands. If, therefore, necessary and universal judgments can anywhere be found in our knowledge, the existence of an a priori that originates independently of experience is ipso facto demonstrated.[147]

The contrast between empirical and a priori judgments, as formulated from the dogmatic standpoint, is the most significant and striking fact in the whole range of human knowledge. A priori judgments claim absolute necessity. They allow of no possible exception. They are valid not only for us, but also for all conceivable beings, however different the specific conditions of their existence, whether they live on the planet Mars or in some infinitely remote region of stellar space, and no matter how diversely their bodily senses may be organised. Through these judgments a creature five feet high, and correspondingly limited by temporal conditions, legislates for all existence and for all time. Empirical judgments, on the other hand, possess only a hypothetical certainty. We recognise that they may be{28} overturned through some addition to our present experience, and that they may not hold for beings on other planets or for beings with senses differently constituted. Whereas the opposite of a rational judgment is not even conceivable, the opposite of an empirical judgment is always possible. The one depends upon the inherent and inalienable nature of our thinking; the other is bound up with the contingent material of sense. The one claims absolute or metaphysical truth: the other is a merely tentative résumé of a limited experience.

The possibility of such a priori judgments had hitherto been questioned only by those who sought to deny to them all possible objective validity. Kant, as a rationalist, has no doubt as to their actual existence. In the Introduction to the second edition he bluntly asserts their de facto existence, citing as instances the propositions of mathematics and the fundamental principles of physical science. Their possibility can be accounted for through the assumption of a priori forms and principles.[148] But with equal emphasis he questions the validity of their metaphysical employment. For that is an entirely different matter. We then completely transcend the world of the senses and pass into a sphere where experience can neither guide nor correct us. In this sphere the a priori is illegitimately taken as being at once the source of our professed knowledge and also the sole criterion of its own claims.

This is the problem, semi-Critical, semi-dogmatic, which is formulated in the letter of 1772 to Herz.[149] What right have we to regard ideas, which as a priori originate from within, as being valid of things in themselves? In so doing we are assuming a pre-established harmony between our human faculties and the ultimately real; and that is an assumption which by its very nature is incapable of demonstration. The proofs offered by Malebranche and by Leibniz are themselves speculative, and consequently presuppose the conclusion which they profess to establish.[150] As above stated, Kant obtained his answer to this problem by way of the logical enquiry into the nature and conditions of a priori judgment.

One of the chief causes, Kant declares, why hitherto metaphysical speculation has passed unchallenged among those who practise it, is the confusion of two very different kinds of judgment, the analytic and the synthetic. Much the greater portion of what reason finds to do consists in the analysis of our concepts of objects.{29}

“As this procedure yields real knowledge a priori, which progresses in secure and useful fashion, reason is so far misled as surreptitiously to introduce, without itself being aware of so doing, assertions of an entirely different order, in which reason attaches to given concepts others completely foreign to them—and moreover attaches them a priori. And yet one does not know how reason comes to do this. This is a question which is never as much as thought of.”[151]

The concepts which are analytically treated may be either empirical or a priori. When they are empirical, the judgments which they involve can have no wider application than the experience to which they give expression; and in any case can only reveal what has all along been thought, though confusedly, in the term which serves as subject of the proposition. They can never reveal anything different in kind from the contents actually experienced. This limitation, to which the analysis of empirical concepts is subject, was admitted by both empiricists and rationalists. The latter sought, however, to escape its consequences by basing their metaphysics upon concepts which are purely a priori, and which by their a priori content may carry us beyond the experienced. But here also Kant asserts a non possibile. A priori concepts, he seeks to show, are in all cases purely logical functions without content, and accordingly are as little capable as are empirical concepts of carrying us over to the supersensible. This is an objection which holds quite independently of that already noted, namely, that their objective validity would involve a pre-established harmony.

What, then, is the nature and what are the generating conditions of synthetic judgments that are also a priori? In all judgments there is a relation between subject and predicate, and that can be of two kinds. Either the predicate B belongs to the subject A, or B lies outside the sphere of the concept A though somehow connected with it. In the former case the judgment is analytic; in the latter it is synthetic. The one simply unfolds what has all along been conceived in the subject concept; the other ascribes to the concept of the subject a predicate which cannot be found in it by any process of analysis. Thus the judgment ‘all bodies are extended’ is analytic. The concept of body already contains that of extension, and is impossible save through it. On the other hand, the judgment ‘all bodies are heavy’ is synthetic. For not body as such, but only bodies which are in interaction with other bodies, are found to develop this{30} property. Bodies can very well be conceived as not influencing one another in any such manner.

There is no difficulty in accounting for analytic judgments. They can all be justified by the principle of contradiction. Being analytic, they can be established a priori. Nor, Kant here claims, is there any difficulty in regard to synthetic judgments that are empirical. Though the predicate is not contained in the subject concept, they belong to each other (though accidentally) as parts of a given empirical whole. Experience is the x which lies beyond the concept A, and on which rests the possibility of the synthesis of B with A. In regard, however, to synthetic judgments which are likewise a priori, the matter is very different. Hitherto, both by the sensationalists and by the rationalists, all synthetic judgments have been regarded as empirical, and all a priori judgments as analytic. The only difference between the opposed schools lies in the relative value which they ascribe to the two types of judgment. For Hume the only really fruitful judgments are the synthetic judgments a posteriori; analytic judgments are of quite secondary value; they can never extend our knowledge, but only clarify its existing content. For Leibniz, on the other hand, true knowledge consists only in the analysis of our a priori concepts, which he regards as possessing an intrinsic and fruitful content; synthetic judgments are always empirical, and as such are purely contingent.[152]

Thus for pre-Kantian philosophy analytic is interchangeable with a priori, and synthetic with a posteriori. Kant’s Critical problem arose from the startling discovery that the a priori and the synthetic do not exclude one another. A judgment may be synthetic and yet also a priori. He appears to have made this discovery under the influence of Hume, through study of the general principle of causality—every event must have a cause.[153] In that judgment there seems to be no connection of any kind discoverable between the subject (the conception of an event as something happening in time) and the predicate (the conception of another event preceding it as an originating cause); and yet we not merely ascribe the one to the other but assert that they are necessarily connected. We can conceive an event as sequent upon a preceding empty time; none the less, in physical enquiry, the causal principle is accepted as an established truth. Here, then, is a new and altogether unique type of judgment, of thoroughly{31} paradoxical nature. So entirely is it without apparent basis, that Hume, who first deciphered its strange character, felt constrained to ascribe our belief in it to an unreasoning and merely instinctive, ‘natural’ habit or custom.

Kant found, however, that the paradoxical characteristics of the causal principle also belong to mathematical and physical judgments. This fact makes it impossible to accept Hume’s sceptical conclusion. If even the assertion 7 + 5 = 12 is both synthetic and a priori, it is obviously impossible to question the validity of judgments that possess these characteristics. But they do not for that reason any the less urgently press for explanation. Such an enquiry might not, indeed, be necessary were we concerned only with scientific knowledge. For the natural sciences justify themselves by their practical successes and by their steady unbroken development. But metaphysical judgments are also of this type; and until the conditions which make a priori synthetic judgment possible have been discovered, the question as to the legitimacy of metaphysical speculation cannot be decided. Such judgments are plainly mysterious, and urgently call for further enquiry.

The problem to be solved concerns the ground of our ascription to the subject concept, as necessarily belonging to it, a predicate which seems to have no discoverable relation to it. What is the unknown x on which the understanding rests in asserting the connection? It cannot be repeated experience; for the judgments in question claim necessity. Nor can such judgments be proved by means of a logical test, such as the inconceivability of the opposite. The absence of all apparent connection between subject and predicate removes that possibility. These, however, are the only two methods of proof hitherto recognised in science and philosophy. The problem demands for its solution nothing less than the discovery and formulation of an entirely novel method of proof.

The three main classes of a priori synthetic judgments are, Kant proceeds, the mathematical, the physical, and the metaphysical. The synthetic character of mathematical judgments has hitherto escaped observation owing to their being proved (as is required of all apodictic certainty) according to the principle of contradiction. It is therefrom inferred that they rest on the authority of that principle, and are therefore analytic. That, however, is an illegitimate inference; for though the truth of a synthetic proposition can be thus demonstrated, that can only be if another synthetic principle is first presupposed. It can never be proved that its truth, as{32} a separate judgment, is demanded by the principle of contradiction. That 7 + 5 must equal 12 does not follow analytically from the conception of the sum of seven and five. This conception contains nothing beyond the union of both numbers into one; it does not tell us what is the single number that combines both. That five should be added to seven is no doubt implied in the conception, but not that the sum should be twelve. To discover that, we must, Kant maintains, go beyond the concepts and appeal to intuition. This is more easily recognised when we take large numbers. We then clearly perceive that, turn and twist our concepts as we may, we can never, by means of mere analysis of them, and without the help of intuition, arrive at the sum that is wanted. The fundamental propositions of geometry, the so-called axioms, are similarly synthetic, e.g. that the straight line between two points is the shortest. The concept ‘straight’ only defines direction; it says nothing as to quantity.

As an instance of a synthetic a priori judgment in physical science Kant cites the principle: the quantity of matter remains constant throughout all changes. In the conception of matter we do not conceive its permanency, but only its presence in the space which it fills. The opposite of the principle is thoroughly conceivable.

Metaphysics is meant to contain a priori knowledge. For it seeks to determine that of which we can have no experience, as e.g. that the world must have a first beginning. And if, as will be proved, our a priori concepts have no content, which through analysis might yield such judgments, these judgments also must be synthetic.

Here, then, we find the essential problem of pure reason. Expressed in a single formula, it runs: How are synthetic a priori judgments possible? To ask this question is to enquire, first, how pure mathematics is possible; secondly, how pure natural science is possible; and thirdly, how metaphysics is possible. That philosophy has hitherto remained in so vacillating a state of ignorance and contradiction is entirely due to the neglect of this problem of a priori synthesis. “Its solution is the question of life and death to metaphysics.” Hume came nearest to realising the problem, but he discovered it in too narrow a form to appreciate its full significance and its revolutionary consequences.

“Greater firmness will be required if we are not to be deterred by inward difficulties and outward opposition from endeavouring, through application of a method entirely different from any hitherto employed,{33} to further the growth and fruitfulness of a science indispensable to human reason—a science whose every branch may be cut away but whose root cannot be destroyed.”[154]

These statements are decidedly ambiguous, owing to Kant’s failure to distinguish in any uniform and definite manner between immanent and transcendent metaphysics.[155] The term metaphysics is used to cover both. Sometimes it signifies the one, sometimes the other; while in still other passages its meaning is neutral. But if we draw the distinction, Kant’s answer is that a genuine and valid immanent metaphysics is for the first time rendered possible by his Critique; its positive content is expounded in the Analytic. Transcendent metaphysics, on the other hand, is criticised in the Dialectic; it is never possible. The existing speculative sciences transgress the limits of experience and yield only a pretence of knowledge. This determination of the limits of our possible a priori knowledge is the second great achievement of the Critique. Thus the Critique serves a twofold purpose. It establishes a new a priori system of metaphysics, and also determines on principles equally a priori the ultimate limits beyond which metaphysics can never advance. The two results, positive and negative, are inseparable and complementary. Neither should be emphasised to the neglect of the other.

Comment on the Argument of Kant’s Introduction

This Introduction, though a document of great historical importance as being the first definite formulation of the generating problem of Kant’s new philosophy, is extremely unsatisfactory as a statement of Critical teaching. The argument is developed in terms of distinctions which are borrowed from the traditional logic, and which are not in accordance with the transcendental principles that Kant is professing to establish. This is, indeed, a criticism which may be passed upon the Critique as a whole. Though Kant was conscious of opening a new era in the history of philosophy, and compares his task with that of Thales, Copernicus, Bacon and Galileo, it may still be said that he never fully appreciated the greatness of his own achievement. He invariably assumes that the revolutionary consequences of his teaching will not extend to the sphere of pure logic. They concern, as he believed, only our metaphysical theories{34} regarding the nature of reality and the determining conditions of our human experience. As formal logic prescribes the axiomatic principles according to which all thinking must proceed, its validity is not affected by the other philosophical disciplines, and is superior to the considerations that determine their truth or falsity. Its distinctions may be securely relied upon in the pioneer labours of Critical investigation. This was, of course, a very natural assumption for Kant to make; and many present-day thinkers will maintain that it is entirely justified. Should that be our attitude, we may approve of Kant’s general method of procedure, but shall be compelled to dissent from much in his argument and from many of his chief conclusions. If, on the other hand, we regard formal logic as in any degree adequate only as a theory of the thought processes involved in the formation and application of the generic or class concept,[156] we shall be prepared to find that the equating of this highly specialised logic with logic in general has resulted in the adoption of distinctions which may be fairly adequate for the purposes in view of which they have been formulated, but which must break down when tested over a wider field. So far from condemning Kant for departing in his later teaching from these hard and fast distinctions, we shall welcome every sign of his increasing independence.

Kant was not, of course, so blind to the real bearing of his principles as to fail to recognise that they have logical implications.[157] He speaks of the new metaphysics which he has created as being a transcendental logic. It is very clear, however, that even while so doing he does not regard it as in any way alternative to the older logic, but as moving upon a different plane, and as yielding results which in no way conflict with anything that formal logic may teach. Indeed Kant ascribes to the traditional logic an almost sacrosanct validity. Both the general framework of the Critique and the arrangement of the minor subdivisions are derived from it. It is supposed to afford an adequate account of discursive thinking, and such supplement as it may receive is regarded as simply an extension of its carefully delimited field. There are two logics, that of discursive or analytic reasoning, and that of synthetic interpretation. The one is formal; the other is transcendental. The one was created by Aristotle, complete at a stroke; Kant professes to have formulated the other in an equally complete and final manner.{35}

This latter claim, which is expressed in the most unqualified terms in the Prefaces to the first and second editions, is somewhat startling to a modern reader, and would seem to imply the adoption of an ultra-rationalistic attitude, closely akin to that of Wolff.

“In this work I have made completeness my chief aim, and I venture to assert that there is not a single metaphysical problem which has not been solved, or for the solution of which the key at least has not been supplied. Reason is, indeed, so perfect a unity that if its principle were insufficient for the solution of even a single one of all the questions to which it itself gives birth, we should be justified in forthwith rejecting it as incompetent to answer, with perfect certainty, any one of the other questions.”[158] “Metaphysics has this singular advantage, such as falls to the lot of no other science which deals with objects (for logic is concerned only with the form of thought in general), that should it, through this Critique, be set upon the secure path of science, it is capable of acquiring exhaustive knowledge of its entire field. It can finish its work and bequeath it to posterity as a capital that can never be added to. For metaphysics has to deal only with principles, and with the limits of their employment as determined by these principles themselves. Since it is a fundamental science, it is under obligation to achieve this completeness. We must be able to say of it: nil actum reputans, si quid superesset agendum.”[159]

These sanguine expectations—by no means supported by the after-history of Kant’s system—are not really due to Kant’s immodest over-estimate of the importance of his work. They would rather seem to be traceable, on the one hand to his continuing acceptance of rationalistic assumptions proper only to the philosophy which he is displacing, and on the other to his failure to appreciate the full extent of the revolutionary consequences which his teaching was destined to produce in the then existing philosophical disciplines. Kant, like all the greatest reformers, left his work in the making. Both his results and his methods call for modification and extension in the light of the insight which they have themselves rendered possible. Indeed, Kant was himself constantly occupied in criticising and correcting his own acquired views; and this is nowhere more evident than in the contrast between the teaching of this Introduction and that of the central portions of the Analytic. But even the later expressions of his maturer views reveal the persisting conflict. They betray the need for further reconstruction, even in the very act of disavowing it. Not an additional logic, but the{36} demonstration of the imperative need for a complete revisal of the whole body of logical science, is the first, and in many respects the chief, outcome of his Critical enquiries.

The broader bearings of the situation may perhaps be indicated as follows. If our account of Kant’s awakening from his dogmatic slumber[160] be correct, it consisted in his recognition that self-evidence will not suffice to guarantee any general principle. The fundamental principles of our experience are synthetic. That is to say, their opposite is in all cases conceivable. Combining this conclusion with his previous conviction that they can never be proved by induction from observed facts, he was faced with the task of establishing rationalism upon a new and altogether novel basis. If neither empirical facts nor intuitive self-evidence may be appealed to, in what manner can proof proceed? And how can we make even a beginning of demonstration, if our very principles have themselves to be established? Principles are never self-evident, and yet principles are indispensable. Such was Kant’s unwavering conviction as regards the fundamental postulates alike of knowledge and of conduct.

This is only another way of stating that Kant is the real founder of the Coherence theory of truth.[161] He never himself employs the term Coherence, and he constantly adopts positions which are more in harmony with a Correspondence view of the nature and conditions of knowledge. But all that is most vital in his teaching, and has proved really fruitful in its after-history, would seem to be in line with the positions which have since been more explicitly developed by such writers as Lotze, Sigwart, Green, Bradley, Bosanquet, Jones and Dewey, and which in their tenets all derive from Hegel’s restatement of Kant’s logical doctrines. From this point of view principles and facts mutually establish one another, the former proving themselves by their capacity to account for the relevant phenomena, and the latter distinguishing themselves from irrelevant accompaniments by their conformity to the principles which make insight possible. In other words, all proof conforms in general type to the hypothetical method of the natural sciences. Kant’s so-called transcendental method, the method by which he establishes the validity of the categories, is itself, as we have already observed,[162] of this character. Secondly, the distinction between the empirical and the a priori must not be taken (as Kant himself takes it in his earlier, and occasionally even in his later utterances) as marking a distinction between two{37} kinds of knowledge. They are elements inseparably involved in all knowledge. And lastly, the contrast between analysis and synthesis becomes a difference not of kind but of degree. Nothing can exist or be conceived save as fitted into a system which gives it meaning and decides as to its truth. In the degree to which it can be studied in relative independence of the supporting system analysis will suffice; in the degree to which it refers us to this system it calls for synthetic interpretation. But ultimately the needs of adequate understanding must constrain us to the employment of both methods of enquiry. Nothing can be known save in terms of the wider whole to which it belongs.

There is, however, one important respect in which Kant diverges in very radical fashion from the position of Hegel. The final whole to which all things must be referred is represented to us only through an “Idea,” for which no corresponding reality can ever be found. The system which decides what is to be regarded as empirically real is the mechanical system of natural science. We have no sufficient theoretical criterion of absolute reality.

These somewhat general considerations may be made more definite if we now endeavour to determine in what specific respects the distinctions employed in the Introduction fail to harmonise with the central doctrines of the Analytic.

In the first place, Kant states his problem in reference only to the attributive judgment. The other types of relational judgment are entirely ignored. For even when he cites judgments of other relational types, such as the propositions of arithmetic and geometry, or that which gives expression to the causal axiom, he interprets them on the lines of the traditional theory of the categorical proposition. As we shall find,[163] it is with the relational categories, and consequently with the various types of relational judgment to which they give rise, that the Critique is alone directly concerned. Even the attributive judgment is found on examination to be of this nature. What it expresses is not the inclusion of an attribute within a given group of attributes, but the organisation of a complex manifold in terms of the dual category of substance and attribute.

Secondly, this exclusively attributive interpretation of the judgment leads Kant to draw, in his Introduction, a hard and fast distinction between the analytic and the synthetic proposition—a distinction which, when stated in such extreme fashion, obscures the real implications of the argument of the Analytic. For Kant here propounds[164] as an exhaustive{38} division the two alternatives: (a) inclusion of the predicate concept within the subject concept, and (b) the falling of the predicate concept entirely outside it. He adds, indeed, that in the latter case the two concepts may still be in some way connected with one another; but this is a concession of which he takes no account in his subsequent argument. He leaves unconsidered the third possibility, that every judgment is both analytic and synthetic. If concepts are not independent entities,[165] as Kant, in agreement with Leibniz, still continues to maintain, but can function only as members of an articulated system, concepts will be distinguishable from one another, and yet will none the less involve one another. In so far as the distinguishable elements in a judgment are directly related, the judgment may seem purely analytic; in so far as they are related only in an indirect manner through a number of intermediaries, they may seem to be purely synthetic. But in every case there is an internal articulation which is describable as synthesis, and an underlying unity that in subordinating all differences realises more adequately than any mere identity the demand for connection between subject and predicate. In other words, all judgments will, on this view, be of the relational type. Even the attributive judgment, as above noted, is no mere assertion of identity. It is always expressed in terms of the dual category of substance and attribute, connecting by a relation contents that as contents may be extremely diverse.

This would seem to be the view to which Kant’s Critical teaching, when consistently developed, is bound to lead. For in insisting that the synthetic character of a judgment need not render it invalid, and that all the fundamental principles and most of the derivative judgments of the positive sciences are of this nature, Kant is really maintaining that the justification of a judgment is always to be looked for beyond its own boundaries in some implied context of coherent experience. But though the value of his argument lies in clear-sighted recognition of the synthetic factor in all genuine knowledge, its cogency is greatly obscured by his continued acceptance of the possibility of judgments that are purely analytic. Thus there is little difficulty in detecting the synthetic character of the proposition: all bodies are heavy. Yet the{39} reader has first been required to admit the analytic character of the proposition: all bodies are extended. The two propositions are really identical in logical character. Neither can be recognised as true save in terms of a comprehensive theory of physical existence. If matter must exist in a state of distribution in order that its parts may acquire through mutual attraction the property of weight, the size of a body, or even its possessing any extension whatsoever, may similarly depend upon specific conditions such as may conceivably not be universally realised. We find the same difficulty when we are called upon to decide whether the judgment 7 + 5 = 12 is analytic or purely synthetic. Kant speaks as if the concepts of 7, 5, and 12 were independent entities, each with its own quite separate connotation. But obviously they can only be formed in the light of the various connected concepts which go to constitute our system of numeration. The proposition has meaning only when interpreted in the light of this conceptual system. It is not, indeed, a self-evident identical proposition; but neither is the connection asserted so entirely synthetic that intuition will alone account for its possibility. That, however, brings us to the third main defect in Kant’s argument.

When Kant states[166] that in synthetic judgments we require, besides the concept of the subject, something else on which the understanding can rely in knowing that a predicate, not contained in the concept, nevertheless belongs to it, he entitles this something x. In the case of empirical judgments, this x is brute experience. Such judgments, Kant implies, are merely empirical. No element of necessity is involved, not even in an indirect manner; in reference to empirical judgments there is no problem of a priori synthesis. Now in formulating the issue in this way, Kant is obscuring the essential purpose of his whole enquiry. He may, without essential detriment to his central position, still continue to preserve a hard-and-fast distinction between analytic and synthetic judgments. In so doing he is only failing to perceive the ultimate consequences of his final results. But in viewing empirical judgments as lacking in every element of necessity, he is destroying the very ground upon which he professes to base the a priori validity of general principles. All judgments involve relational factors of an a priori character. The appeal to experience is the appeal to an implied system of nature. Only when fitted into the context yielded by such a system can an empirical proposition have meaning, and only in the light of such a presupposed system{40} can its truth be determined. It can be true at all, only if it can be regarded as necessarily holding, under the same conditions, for all minds constituted like our own. Assertion of a contingent relation—as in the proposition: this horse is white—is not equivalent to contingency of assertion. Colour is a variable quality of the genus horse, but in the individual horse is necessarily determined in some particular mode. If a horse is naturally white, it is necessarily white. Though, therefore, in the above proposition, necessity receives no explicit verbal expression, it is none the less implied.

In other words, the distinction between the empirical and the a priori is not, as Kant inconsistently assumes in this Introduction, a distinction between two kinds of synthesis or judgment, but between two elements inseparably involved in every judgment. Experience is transcendentally conditioned. Judgment is in all cases the expression of a relation which implies an organised system of supporting propositions; and for the articulation of this system a priori factors are indispensably necessary.

But the most flagrant example of Kant’s failure to live up to his own Critical principles is to be found in his doctrine of pure intuition. It represents a position which he adopted in the pre-Critical period. It is prefigured in Ueber die Deutlichkeit der Grundsätze (1764),[167] and in Von dem ersten Grunde des Unterschiedes der Gegenden im Raume (1768),[168] and is definitely expounded in the Dissertation (1770).[169] That Kant continued to hold this doctrine, and that he himself regarded it as an integral part of his system, does not, of course, suffice to render it genuinely Critical. As a matter of fact, it is really as completely inconsistent with his Critical standpoint as is the view of the empirical proposition which we have just been considering. An appeal to our fingers or to points[170] is as little capable, in and by itself, of justifying any a priori judgment as are the sense-contents of grounding an empirical judgment. Even when Kant is allowed the benefit of his own more careful statements,[171] and is taken as asserting that arithmetical propositions are based on a pure a priori intuition which can find only approximate expression in sensuous terms, his statements run counter to the main tendencies of his Critical teaching, as well as to the recognised methods of the mathematical sciences. Intuition may, as Poincaré and others have maintained, be an indispensable element in all mathematical concepts; it cannot afford proof{41} of any general theorem. The conceptual system which directs our methods of decimal counting is what gives meaning to the judgment 7 + 5 = 12; it is also what determines that judgment as true. The appeal to intuition in numerical judgments must be regarded only as a means of imaginatively realising in a concrete form the abstract relations of some such governing system, or else as a means of detecting relations not previously known. The last thing in the world which such a method can yield is universal demonstration. This is equally evident in regard to geometrical propositions. That a straight line is the shortest distance between two points, cannot be proved by any mere appeal to intuition. The judgment will hold if it can be assumed that space is Euclidean in character; and to justify that assumption it must be shown that Euclidean concepts are adequate to the interpretation of our intuitional data. Should space possess a curvature, the above proposition might cease to be universally valid. Space is not a simple, unanalysable datum. Though intuitionally apprehended, it demands for its precise determination the whole body of geometrical science.[172]

The comparative simplicity of Kant’s intuitional theory of mathematical science, supported as it is by the seemingly fundamental distinction between abstract concepts of reflective thinking and the construction of concepts[173] in geometry and arithmetic, has made it intelligible even to those to whom the very complicated argument of the Analytic makes no appeal. It would also seem to be inseparably bound up with what from the popular point of view is the most striking of all Kant’s theoretical doctrines, namely, his view that space and time are given subjective forms, and that the assertion of their independent reality must result in those contradictions to which Kant has given the title antinomy. For these reasons his intuitional theory of mathematical science has received attention out of all proportion to its importance. Its pre-Critical character has been more or less overlooked, and instead of being interpreted in the light of Critical principles, it has been allowed to obscure the sounder teaching of the Analytic. In this matter Schopenhauer is a chief culprit. He not only takes the views of mathematical science expounded in the Introduction and Aesthetic as being in line with Kant’s main teaching, but expounds them in an even more unqualified fashion than does Kant himself.{42}

There are thus four main defects in the argument of this Introduction, regarded as representative of Critical teaching. (1) Its problems are formulated exclusively in terms of the attributive judgment; the other forms of relational judgment are ignored. (2) It maintains that judgments are either merely analytic or completely synthetic. (3) It proceeds in terms of a further division of judgments into those that are purely empirical and those that are a priori. (4) It seems to assert that the justification for mathematical judgments is intuitional. All these four positions are in some degree retained throughout the Critique, but not in the unqualified manner of this Introduction. In the Analytic, judgment in all its possible forms is shown to be a synthetic combination of a given manifold in terms of relational categories. This leads to a fourfold conclusion. In the first place, judgment must be regarded as essentially relational. Secondly, the a priori and the empirical must not be taken as two separate kinds of knowledge, but as two elements involved in all knowledge. Thirdly, analysis and synthesis must not be viewed as co-ordinate processes; synthesis is the more fundamental; it conditions all analysis. And lastly, it must be recognised that nothing is merely given; intuitional experience, whether sensuous or a priori, is conditioned by processes of conceptual interpretation. Though the consequences which follow from these conclusions, if fully developed, would carry us far beyond any point which Kant himself reached in the progressive maturing of his views, the next immediate steps would still be on the strict lines of the Critical principles, and would involve the sacrifice only of such pre-Critical doctrines as that of the intuitive character of mathematical proof. Such correction of Kant’s earlier positions is the necessary complement of his own final discovery that sense-intuition is incapable of grounding even the so-called empirical judgment.


The Introduction to the first edition bears all the signs of having been written previous to the central portions of the Analytic.[174] That it was not, however, written prior to the Aesthetic seems probable. The opening sections of the Aesthetic represent what is virtually an independent introduction which takes no account of the preceding argument, and which redefines terms and distinctions that have already{43} been dwelt upon. The extensive additions which Kant made in recasting the Introduction for the second edition are in many respects a great improvement. In the first edition Kant had not, except when speaking of the possibility of constructing the concepts of mathematical science, referred to the synthetic character of mathematical judgments. This is now dwelt upon in adequate detail. Kant’s reason for not making the revision more radical was doubtless his unwillingness to undertake the still more extensive alterations which this would have involved. Had he expanded the opening statement of the second edition Introduction, that even our empirical knowledge is a compound of the sensuous and the a priori, an entirely new Introduction would have become necessary. The additions made are therefore only such as will not markedly conflict with the main tenor of the argument of the first edition.

How Are Synthetic a priori Judgments Possible?

Treatment of detailed points will be simplified if we now consider in systematic fashion the many difficulties that present themselves in connection with Kant’s mode of formulating his central problem: How are synthetic a priori judgments possible? This formula is less definite and precise than would at first sight appear. The central phrase ‘synthetic a priori’ is sufficiently exact (the meaning to be attached to the a priori has already been considered[175]), but ambiguities of the most various kinds lurk in the seemingly innocent and simple terms with which the formula begins and ends:

A. ‘How’ has two very different meanings:

    (a) How possible = in what manner possible = wie.

    (b) How possible = in how far possible, i.e. whether possible = ob.

In connection with these two meanings of the term ‘how,’ we shall have to consider the distinction between the synthetic method employed in the Critique and the analytic method employed in the Prolegomena.

B. ‘Possible’ has a still wider range of application. Vaihinger[176] distinguishes within it no less than three pairs of alternative meanings:

(a) Psychological and logical possibility.

(b) Possibility of explanation and possibility of existence.

(c) Real and ideal possibility.


A. Kant personally believed that the possibility of valid a priori synthetic judgment is proved by the existing sciences of mathematics and physics. And that being so, there were for Kant two very different methods which could be employed in accounting for their possibility, the synthetic or progressive, and the analytic or regressive. The synthetic method would start from given, ordinary experience (in its simplest form, as consciousness of time), to discover its conditions, and from them to prove the validity of knowledge that is a priori. The analytic method would start “from the sought as if it were given,” that is, from the existence of a priori synthetic judgments, and, assuming them as valid, would determine the conditions under which alone such validity can be possible. The precise formulation of these two methods, the determination of their interrelations, of their value and comparative scope, is a matter of great importance, and must therefore be considered at some length.

The synthetic method may easily be confounded with the analytic method. For in the process of its argument it makes use of analysis. By analysing ordinary experience in the form in which it is given, it determines (in the Aesthetic and in the Analytic of Concepts) the fundamental elements of which knowledge is composed, and the generating conditions from which it results. From these the validity of the a priori principles that underlie mathematics and physics can (in the Analytic of Principles) be directly deduced. The fundamental differentiating feature, therefore, of the so-called synthetic method is not its synthetic procedure, since in great part, in the solution of the most difficult portion of its task, it employs an analytic method, but only its attitude towards the one question of the validity of a priori synthetic knowledge. It does not postulate this validity as a premiss, but proves it as a consequence of conditions which are independently established. By a preliminary regress upon the conditions of our de facto consciousness it acquires data from which it is enabled to advance by a synthetic, progressive or deductive procedure to the establishment of the validity of synthetic a priori judgments. The analytic method, on the other hand, makes no attempt to prove the validity of a priori knowledge. It seeks only to discover the conditions under which such knowledge, if granted to exist, can possess validity, and in the light of which its paradoxical and apparently contradictory features can be viewed as complementary to one another. The conditions, thus revealed, will render the validity of knowledge conceivable, will account for it once it has been assumed; but they do not prove it.{45} The validity is a premiss; the whole argument rests upon the assumption of its truth. The conditions are only postulated as conditions; and their reality becomes uncertain, if the validity, which presupposes them, is itself called in question. Immediately we attempt to reverse the procedure, and to prove validity from these conditions, our argument must necessarily adopt the synthetic form; and that, as has been indicated, involves the prior application of a very different and much more thorough process of analysis. The distinction between the two methods may therefore be stated as follows. In the synthetic method the grounds which are employed to explain a priori knowledge are such as also at the same time suffice to prove its validity. In the analytic method they are grounds of explanation, but not of proof. They are themselves proved only in so far as the assumption of validity is previously granted.

The analytic procedure which is involved in the complete synthetic method ought, however, for the sake of clearness, to be classed as a separate, third, method. And as such I shall henceforth regard it. It establishes by an independent line of argument the existence of a priori factors, and also their objective validity as conditions necessary to the very possibility of experience. So viewed, it is the most important and the most fundamental of the three methods. The argument which it embodies constitutes the very heart of the Critique. It is, indeed, Kant’s new transcendental method; and in the future, in order to avoid confusion with the analytic method of the Prolegomena, I shall refer to it always by this title. It is because the transcendental method is an integral part of the complete, synthetic method, but cannot be consistently made a part of the analytic method, that the synthetic method alone serves as an adequate expression of the Kantian standpoint. This new transcendental method is proof by reference to the possibility of experience. Experience is given as psychological fact. The conditions which can alone account for it, as psychological fact, also suffice to prove its objective validity; but at the same time they limit that validity to the phenomenal realm.

We have next to enquire to what extent these methods are consistently employed in the Critique. This is a problem over which there has been much controversy, but which seems to have been answered in a quite final manner by Vaihinger. It is universally recognised that the Critique professes to follow the synthetic method, and that the Prolegomena, for the sake of a simpler and more popular form of exposition, adopts the analytic method. How far{46} these two works live up to their professions, especially the Critique in its two editions, is the only point really in question. Vaihinger found two diametrically opposed views dividing the field. Paulsen, Riehl, and Windelband maintain the view that Kant starts from the fact that mathematics, pure natural science, and metaphysics contain synthetic a priori judgments claiming to be valid. Kant’s problem is to test these claims; and his answer is that they are valid in mathematics and pure natural science, but not in metaphysics. Paulsen, and those who follow him, further contend that in the first edition this method is in the main consistently held to, but that in the second edition, owing to the occasional employment (especially in the Introduction) of the analytic method of the Prolegomena, the argument is perverted and confused: Kant assumes what he ought first to have proved. Fischer, on the other hand, and in a kindred manner also B. Erdmann, maintain that Kant never actually doubted the validity of synthetic a priori judgments; starting from their validity, in order to explain it, Kant discovers the conditions upon which it rests, and in so doing is able to show that these conditions are not of such a character as to justify the professed judgments of metaphysics.

Vaihinger[177] combines portions of both views, while completely accepting neither. Hume’s profound influence upon the development and formulation of Kant’s Critical problem can hardly be exaggerated, but it ought not to prevent us from realising that this problem, in its first form, was quite independently discovered. As the letter of 1772 to Herz clearly shows,[178] Kant was brought to the problem, how an idea in us can relate to an object, by the inner development of his own views, through reflection upon the view of thought which he had developed in the Dissertation of 1770. The conformity between thought and things is in that letter presented, not as a sceptical objection, but as an actual fact calling for explanation. He does not ask whether there is such conformity, but only how it should be possible. Even after the further complication, that thought is synthetic as well as a priori, came into view through the influence of Hume, the problem still continued to present itself to Kant in this non-sceptical light. And this largely determines the wording of his exposition, even in passages in which the demands of the synthetic method are being quite amply fulfilled. Kant, as it would seem, never himself doubted the validity of the mathematical sciences. But since their validity is not beyond possible impeachment, and since metaphysical knowledge, which is{47} decidedly questionable, would appear to be of somewhat similar type, Kant was constrained to recognise that, from the point of view of strict proof, such assumption of validity is not really legitimate. Though, therefore, the analytic method would have resolved Kant’s own original difficulty, only the synthetic method is fully adequate to the situation.

Kant accordingly sets himself to prove that whether or not we are ready (as he himself is) to recognise the validity of scientific judgments, the correctness of this assumption can be firmly established. And being thus able to prove its correctness, he for that very reason does not hesitate to employ it in his introductory statement. The problem, he says, is that of ‘understanding’ how synthetic a priori judgments can be valid. A ‘difficulty,’ a ‘mystery,’ a ‘secret,’ lies concealed in them. How can a predicate be ascribed to a subject term which does not contain it? And even more strangely (if that be possible), how can a priori judgments legislate for objects which are independent existences? Such judgments, even if valid beyond all disputing, would still call for explanation. This is, indeed, Kant’s original and ground problem. As already indicated, no one, save only Hume, had hitherto perceived its significance. Plato, Malebranche, and Crusius may have dwelt upon it, but only to suggest explanations still stranger and more mystical than the mysterious fact itself.[179]

Paulsen is justified in maintaining that Kant, in both editions of the Critique, recognises the validity of mathematics and pure natural science. The fact of their validity is less explicitly dwelt upon in the first edition, but is none the less taken for granted. The sections transferred from the Prolegomena to the Introduction of the second edition make no essential change, except merely in the emphasis with which Kant’s belief in the existence of valid a priori synthetic judgments is insisted upon. As has already been stated, only by virtue of this initial assumption is Kant in position to maintain that there is an alternative to the strict synthetic method. The problem from which he starts is common to both methods, and for that reason the formulation used in the Prolegomena can also be employed in the Introduction to the Critique. Only in their manner of solving the problem need they differ.[180] Kant’s Critical problem first begins with this presupposition of validity, and does not {48}exist save through it.[181] He does not first seek to discover whether such judgments are valid, and then to explain them. He accepts them as valid, but develops a method of argument which suffices for proof as well as for explanation. The argument being directed to both points simultaneously, and establishing both with equal cogency, it may legitimately be interpreted in either way, merely as explanation, or also as proof. Kant does not profess or attempt to keep exclusively to any one line of statement. Against the dogmatists he insists upon the necessity of explaining the validity of a priori synthetic judgments, against the sceptics upon the possibility of proving their validity. And constantly he uses ambiguous terms, such as ‘justification’ (Rechtfertigung), ‘possibility,’ that may indifferently be read in either sense. But though the fundamental demand which characterises the synthetic method in its distinction from the analytic thus falls into the background, and is only occasionally insisted upon, it is none the less fulfilled. So far as regards the main argument of the Critique in either edition, the validity of synthetic a priori judgments is not required as a premiss. It is itself independently proved.

The manner in which Kant thus departs from the strict application of the synthetic method may be illustrated by an analysis of his argument in the Aesthetic.[182] Only in the arguments of the first edition in regard to space and time is the synthetic method employed in its ideal and rigorous form. For the most part, even in the first edition, instead of showing how the a priori character of pure and applied mathematics follows from conclusions independently established, he assumes both pure and applied mathematics to be given as valid, and seeks only to show how the independently established results of the Aesthetic enable him to explain and render comprehensible their recognised characteristics. This is not, indeed, any very essential modification of the synthetic method; for his independently established results suffice for deducing all that they are used to explain. The validity of mathematics is not employed as a premiss. Kant’s argument is, however, made less clear by the above procedure.

Further difficulty is caused by Kant’s occasional employment, even in the first edition, of the analytic method. He several times cites as an argument in support of his view{49} of space the fact that it alone will account for the existing science of geometry. That is to say, he employs geometry, viewed as valid, to prove the correctness of his view of space.[183] Starting from that science as given, he enquires what are the conditions which can alone render it possible. These conditions are found to coincide with those independently established. Now this is a valid argument when employed in due subordination to the main synthetic method. It offers welcome confirmation of the results of that method. It amounts in fact to this, that having proved (by application of the transcendental method) the mathematical sciences to be valid, everything which their validity necessarily implies must be granted. Kant’s reasoning here becomes circular, but it is none the less valid on that account. This further complication of the argument is, however, dangerously apt to mislead the reader. It is in great part the cause of the above division among Kant’s commentators. The method employed in the Prolegomena is simply this form of argument systematised and cut free from all dependence upon the transcendental method of proof.[184]

The whole matter is, however, still further complicated by the distinction, which we have already noted, between real and ideal possibility. Are the given synthetic a priori judgments valid? That is one question. Can the Critical philosophy discover, completely enumerate, and prove in a manner never before done, all the possible synthetic a priori principles? That is a very different problem, and when raised brings us to the further discussion of Kant’s transcendental method. The question at issue is no longer merely whether or not certain given judgments are valid, and how, if valid, they are to be accounted for. The question is now that of discovering and of proving principles which have not been established by any of the special sciences. This shifting of the problem is concealed from Kant himself by his omission to distinguish between the undemonstrated axioms of the mathematical sciences and their derivative theorems, between the principles employed by the physicist without enquiry into their validity and the special laws based upon empirical evidence.{50}

As regards the mathematical axioms, the problem is fairly simple. As we shall see later, in the Aesthetic, they do not require a deduction in the strict transcendental sense. They really fall outside the application of the transcendental method. They require only an “exposition.” But in regard to the fundamental principles of natural science we are presented with the problem of discovery as well as of proof. Unlike the axioms of the mathematician, they are frequently left unformulated. And many postulates, such as that there is a lex continui in natura, are current in general thought, and claim equal validity with the causal principle. Kant has thus to face the question whether in addition to those principles employed more or less explicitly by the scientist, others, such as might go to form an immanent metaphysics of nature, may not also be possible.

B. (a)[185] Psychological and logical possibility.—Both have to be recognised and accounted for. Let us consider each in order.

(1) Psychological possibility.—What are the subjective conditions of a priori synthetic judgments? Through what mental faculties are they rendered possible? Kant replies by developing what may be called a transcendental psychology. They depend upon space and time as forms of sensibility, upon the a priori concepts of understanding, and upon the synthetic activities by which the imagination schematises these concepts and reduces the given manifold to the unity of apperception. This transcendental psychology is the necessary complement of the more purely epistemological analysis.[186] But on this point Kant’s utterances are extremely misleading. His Critical enquiry has, he declares, nothing in common with psychology. In the Preface to the first edition we find the following passage: “This enquiry ... [into] the pure understanding itself, its possibility and the cognitive faculties upon which it rests ..., although of great importance for my chief purpose, does not form an essential part of it.”[187] The question, he adds, “how is the faculty of thought itself possible?... is as it were a search for the cause of a given effect, and therefore is of the nature of an hypothesis [or ‘mere opinion’], though, as I shall show elsewhere, this is not really so.” The concluding words of this passage very fairly express Kant’s hesitating and inconsistent procedure. Though he has so explicitly eliminated from the central enquiry of{51} the Critique all psychological determination of the mental powers, statements as to their constitution are none the less implied, and are involved in his epistemological justification alike of a priori knowledge and of ordinary experience. If we bear in mind that Kant is here attempting to outline the possible causes of given effects, and that his conclusions are therefore necessarily of a more hypothetical character than those obtained by logical analysis, we shall be prepared to allow him considerable liberty in their formulation. But in certain respects his statements are precise and definite—the view, for instance, of sensations as non-spatial, of time as a form of inner sense, of the productive imagination as pre-conditioning our consciousness, of spontaneity as radically distinct from receptivity, of the pure forms of thought as not acquired through sense, etc. No interpretation which ignores or under-estimates this psychological or subjective aspect of his teaching can be admitted as adequate.[188]

(2) Logical or epistemological possibility.—How can synthetic a priori judgments be valid? This question itself involves a twofold problem. How, despite their synthetic character, can they possess truth, i.e. how can we pass from their subject terms to their predicates? And secondly, how, in view of their origin in our human reason, can they be objectively valid, i.e. legislate for the independently real? How can we pass beyond the subject-predicate relation to real things? This latter is the Critical problem in the form in which it appears in Kant’s letter of 1772 to Herz.[189] The former is the problem of synthesis which was later discovered.

(b) (1) Possibility of explanation and (2) possibility of existence.—(1) How can synthetic a priori judgments be accounted for? How, despite their seemingly inconsistent and apparently paradoxical aspects, can their validity (their validity as well as their actuality being taken for granted) be rendered comprehensible? (2) The validity of such judgments has been called in question by the empiricists, and is likewise inexplicable even from the dogmatic standpoint of the rationalists. How, then, can these judgments be possible at all? These two meanings of the term ‘possible’ connect with the ambiguity, above noted, in the term ‘how.’ The former problem can be solved by an analytic method; the latter demands the application of the more radical method of synthetic reconstruction.

(c) Real and ideal possibility.[190]—We have to distinguish between the possible validity of those propositions which the mathematical and physical sciences profess to have established{52} and the possible validity of those principles such as that of causality, which are postulated by the sciences, but which the sciences do not attempt to prove, and which in certain cases they do not even formulate. The former constitute an actually existent body of scientific knowledge, demonstrated in accordance with the demands of scientific method. The latter are employed by the scientist, but are not investigated by him. The science into which they can be fitted has still to be created; and though some of the principles composing it may be known, others remain to be discovered. All of them demand such proof and demonstration as they have never yet received.[191] This new and ideal science is the scientific metaphysics which Kant professes to inaugurate by means of the Critique. In reference to the special sciences, possibility means the conditions of the actually given. In reference to the new and ideal metaphysics, possibility signifies the conditions of the realisation of that which is sought. In view of this distinction, the formula—How are synthetic a priori judgments possible?—will thus acquire two very different meanings. (1) How are the existing a priori synthetic judgments to be accounted for? (2) How may all the really fundamental judgments of that type be exhaustively discovered and proved? Even in regard to immanent metaphysics Kant interprets the formula in both ways. This is due to his frequent confusion of immanent metaphysics with the principles of natural science. Its propositions are then regarded as given, and only their general validity calls for proof. It is, however, in the problem of ideal possibility that the essential problem of the Critique lies; and that is a further reason why it cannot be adequately dealt with, save by means of the synthetic method.


Experience.—Throughout the Introduction the term experience[192] has (even at times in one and the same sentence) two quite distinct meanings, (1) as product of sense and understanding acting co-operatively, and (2) as the raw material (the impressions) of sense. Considerable confusion is thereby caused.

Understanding and reason[193] are here, as often elsewhere in the Critique, used as equivalent terms. Throughout the entire two first sections of the Introduction to the second edition the term reason does not occur even once. As first mentioned,[194] it is taken as the source of metaphysical judgments.{53}

General (a priori) truths have an inner necessity and must be clear and certain by themselves.[195]—These statements are not in accordance with Kant’s new Critical teaching.[196] They have remained uncorrected from a previous way of thinking. This must be one reason for the recasting of this paragraph in the second edition.

Even with (unter) our experiences there is mingled knowledge which must be of a priori origin.[197]—Kant is here distinguishing the immanent a priori, such as that involved in any causal judgment, from the transcendent a priori dwelt upon in the next paragraph. The latter is expressed through metaphysical judgments, such as ‘God exists,’ ‘the soul is immortal.’

Original concepts and judgments derived from them.[198]—Cf. B 5-6.

Pure.—In the title of the section the term pure[199] (rein) is, as the subsequent argument shows, taken as exactly equivalent to a priori. As Vaihinger notes, the adjective apriorisch had not yet been invented. The opposite of pure is here empirical (empirisch).[200]

All our knowledge begins with experience.[201]—This is a stronger statement than any in the corresponding paragraphs of the first edition. Had Kant proceeded to develop its consequences, he would have had to recast the entire Introduction, setting the problem of empirical knowledge alongside that of the a priori.[202] As it is, he is forced[203] to subdivide the absolutely a priori into the pure and the mixed.[204]

By objects which affect (rühren) our senses. The raw material of sensuous impressions.[205]—These incidental statements call for discussion. Cf. below, pp. 80-8, 120-1, 274 ff.

A knowledge of objects which we call experience.[206]—Kant does not keep to this definition. The term experience is still used in its other and narrower sense, as in the very next paragraph, when Kant states that knowledge does not, perhaps, arise solely from experience (= sense impressions).

In respect of time.[207]—This statement, taken as an account of Kant’s teaching in the Critique, is subject to two reservations. In the Aesthetic[208] Kant sometimes claims a temporal antecedence for the a priori. And secondly, the a priori is not for Kant merely logical. It also possesses a dynamical priority.[209]

Even experience itself is a compound.[210]—The “even” seems to refer to the distinction drawn in A 2 between the immanent and the transcendent a priori.[211]


It is therefore a question whether there exists such knowledge independent of experience.[212]—This question was not raised in the first edition.[213] The alternative methods, analytic and synthetic, are discussed above, p. 44 ff.

Such knowledge is called a priori and is distinguished from empirical knowledge.[214]—Throughout the Introduction, in both editions equally, Kant fails to state the problems of the Critique in a sufficiently comprehensive manner. He speaks as if the Critique dealt only with the absolutely a priori, in its two forms, as immanent scientific knowledge and as transcendent speculation. It also deals with the equally important and still more fundamental problem of accounting for the possibility of experience.[215] Our empirical knowledge involves an a priori element, and may not therefore be opposed to a priori knowledge in the manner of the passage before us.

This term a priori is not yet definite enough.[216]—It is frequently employed in a merely relative sense. Thus we can say of a person who undermines the foundations of his house that he might have known a priori that it would collapse, that is, that he need not wait for the experience of its actual fall. But still he could not know this entirely a priori; he had first to learn from experience that bodies are heavy, and will fall when their supports are taken away. But as dealt with in the Critique the term a priori is used in an absolute sense, to signify that knowledge which is independent, not of this or that experience only, but of all impressions of the senses. Thus far Kant’s position is comparatively clear; but he proceeds to distinguish two forms within the absolutely a priori, namely, mixed and pure. The absolutely a priori is mixed when it contains an empirical element, pure when it does not. (“Pure” is no longer taken in the meaning which it has in the title of the section.[217] It signifies not the a priori as such, but only one subdivision of it.) Thus after defining absolutely a priori knowledge as independent of all experience, Kant takes it in one of its forms as involving empirical elements. The example which he gives of an absolutely a priori judgment, which yet is not pure, is the principle: every change has its cause. “Change” is an empirical concept, but the synthetic relation asserted is absolutely a priori. In the next section[218] this same proposition is cited as a pure judgment a priori—“pure” being again used in its more general meaning as synonymous with a priori. This confusion results from Kant’s exclusive preoccupation with the a priori, and consequent{55} failure to give due recognition to the correlative problem of the empirical judgment. The omitted factor retaliates by thus forcing its way into Kant’s otherwise clean-cut divisions. Also, it is not true that the relative a priori falls outside the sphere of the Critical enquiry. Such judgment expresses necessity or objectivity, and for that reason demands a transcendental justification no less urgently than the absolutely a priori. The finding of such justification is, indeed, the central problem of the Analytic.[219]

The subdivisions of the a priori may be tabulated thus:

A priori knowledge— Relative, e.g. every unsupported house must fall.
Absolute—Mixed, e.g. every change has its cause.
Pure, e.g. a straight line is the shortest
distance between two points.

The term pure (rein) thus acquires a second meaning distinct from that defined above.[220] It is no longer employed as identical with a priori, but as a subdivision of it, meaning unmixed. Its opposite is no longer the empirical, but the impure or mixed. Owing, however, to the fact that “pure” (in its first meaning) is identical with the a priori, it shares in all the different connotations of the latter, and accordingly is also employed to denote that which is not relative. But “pure” has yet another meaning peculiar to itself. The phrase “independent of experience” has in reference to “pure” an ambiguity from which it does not suffer in its connection with “a priori” (since mathematical knowledge, whether pure or applied, is always regarded by Kant as a priori). It may signify either independence as regards content and validity, or independence as regards scope. The latter meaning is narrower than the former. By the former meaning it denotes that which originates, and can possess truth, independently of experience. By the latter it signifies that which is not only independent of sense but also applies to the non-sensuous. In this latter meaning pure knowledge therefore signifies transcendent knowledge. Its opposite is the immanent. The various meanings of “pure” (four in number) may be tabulated as follows:

(a) (1) A priori: independent of experience as regards origin and validity. (Its opposite = empirical.)
        (2) Absolutely independent of experience. (Its opposite = relative.)
        (3) Unmixed with experience. (Its opposite = impure or mixed.){56}
(b) (4) Independent of experience as regards scope = transcendent. (Its opposite = immanent.)

All these varied meanings contribute to the ambiguity of the title of the Critique. Kant himself employs the title in all of the following senses:

1. Critique of absolutely pure a priori knowledge, determination of its sources, conditions, scope and limits.

2. Critique of all a priori knowledge, relative as well as absolute, in so far as it depends upon a priori principles, determination, etc.

3. Critique of all knowledge, whether a priori or empirical, determination, etc.

4. Critique of transcendent knowledge, its sources and limits.

Further meanings could also be enumerated but can be formulated by the reader for himself in the light of the ambiguities just noted.[221] The special context in each case can alone decide how the title is to be understood. If a really adequate definition of the purpose and scope of the Critique is sought by the reader, he must construct it for himself. The following may perhaps serve. The Critique is an enquiry into the sources, conditions, scope and limits of our knowledge, both a priori and empirical, resulting in the construction of a new system of immanent metaphysics; in the light of the conclusions thus reached, it also yields an analysis and explanation of the transcendental illusion to which transcendent metaphysics, both as a natural disposition and as a professed science, is due.

Kant further complicates matters by offering a second division of the absolutely a priori,[222] viz. into the original and the derivative. Also, by implication, he classes relative a priori judgments among the propositions to be reckoned with by the Critique; and yet in B 4 he speaks of the proposition, all bodies are heavy, as merely empirical.[223]

A criterion.[224]—Necessity and universality are valid criteria of the a priori (= the non-empirical). This follows from Kant’s view[225] of the empirical as synonymous with the contingent (zufällig). Experience gives only the actual; the a priori alone yields that which cannot be otherwise.

“Necessity and strict universality are thus safe criteria of a priori knowledge, and are inseparable from one another. But since in the employment of these criteria the empirical limitation of judgments{57} is sometimes more easily shown than their contingency, or since, as frequently happens, their unlimited universality can be more convincingly proved than their necessity, it is advisable to use the two criteria separately, each being by itself infallible.”[226]

Now Kant is here, of course, assuming the main point to be established, namely, that experience is incapable of accounting for such universality and necessity as are required for our knowledge, both ordinary and scientific. We have already considered this assumption,[227] and have also anticipated misunderstanding by noting the important qualifications to which, from Kant’s new Critical standpoint, the terms ‘necessity’ and ‘universality’ become subject.[228] The very specific meaning in which Kant employs the term a priori must likewise be borne in mind. Though negatively the a priori is independent of experience, positively it originates in our human reason. The necessity and universality which differentiate the a priori distinguish it only from the humanly accidental. The a priori has no absolute validity. From a metaphysical standpoint, it is itself contingent. As already stated,[229] all truth is for Kant merely de facto. The necessary is not that which cannot be conceived to be otherwise, nor is it the unconditioned. Our reason legislates only for the world of appearance. But as yet Kant gives no hint of this revolutionary reinterpretation of the rationalist criteria. One of the chief unfortunate consequences of the employment in this Introduction of the analytic method of the Prolegomena is that it tends to mislead the reader by seeming to commit Kant to a logical a priori of the Leibnizian type.

To show that, if experience is to be possible, [pure a priori propositions] are indispensable, and so to prove their existence a priori.[230]—At first sight Kant would seem to be here referring to the alternative synthetic method of procedure, i.e. to the transcendental proof of the a priori. The next sentence shows, however, that neither in intention nor in fact is that really so. He argues only that a priori principles, such as the principle of causality, are necessary in order to give “certainty” to our experience; such a principle must be postulated if inductive inference is to be valid. Experience could have no [scientific] certainty, “if all rules according to which it proceeds were themselves in turn empirical, and therefore contingent. They could hardly be regarded as first principles.” There is no attempt here to prove that empirical knowledge as such necessarily involves the a priori. Also the method of argument, though{58} it seeks to establish the necessity of the a priori, is not transcendental or Critical in character. It is merely a repetition of the kind of argument which both Hume and Leibniz had already directed against the sensationalist position.[231] Very strangely, considering that these sentences have been added in the second edition, and therefore subsequent to the writing of the objective deduction, Kant gives no indication of the deeper problem to which he finally penetrated. The explanation is, probably, that to do so would have involved the recasting of the entire Introduction. Even on the briefest reference, the hard-and-fast distinction between the a priori and the empirical, as two distinct and separate classes of judgment, would have been undermined, and the reader would have been made to feel the insufficiency of the analysis upon which it is based.[232] The existence of the deeper view is betrayed only through careless employment of the familiar phrase “possibility of experience.” For, as here used, it is not really meant. “Certainty of experience”—a very different matter—is the meaning that alone will properly fit the context.

Reason and understanding.[233]—They are here distinguished, having been hitherto, in A 1-2, employed as synonymous. The former carries us beyond the field of all possible experience; the latter is limited to the world of sense. Thus both Reason and understanding are here used in their narrowest meaning.

These inevitable problems of pure Reason itself are God, freedom, and immortality. The science which, with all its methods, is in its final intention directed solely to the solution of these problems, is called metaphysics.[234]—These sentences are characteristic of the second edition with its increased emphasis upon the positive results of the Critique on the one hand, and with its attitude of increased favour towards transcendent metaphysics on the other. The one change would seem to be occasioned by the nature of the criticisms passed upon the first edition, as, for instance, by Moses Mendelssohn who describes Kant as “the all-destroyer” (der alles zermalmende). The other is due to Kant’s preoccupation with the problems of ethics and of teleology. The above statements are repeated with even greater emphasis in B 395 n.[235] The definition here given of metaphysics is not strictly kept to by Kant. As above noted,[236] Kant really distinguishes within it two forms, immanent and transcendent. In so doing, however, he still[237] regards transcendent metaphysics as the more important.{59} Immanent metaphysics is chiefly of value as contributing to the solution of the “inevitable problems of pure Reason.”

A 3-4 = B 7-8.—The reasons, here cited by Kant, for the failure of philosophical thinking to recognise the difference between immanent and transcendent judgments are: (1) the misunderstood character, and consequent misleading influence, of a priori mathematical judgments; (2) the fact that once we are beyond the sensible sphere, experience can never contradict us; (3) natural delight in the apparent enlargement of our knowledge; (4) the ease with which logical contradictions can be avoided; (5) neglect of the distinction between analytic and synthetic a priori judgments. Vaihinger points out[238] that in the Fortschritte[239] Kant adds a sixth reason—confusion of the concepts of understanding with the Ideas of Reason. Upon the first of the above reasons the best comment is that of the Methodology.[240] But the reader must likewise bear in mind that in B xvi Kant develops his new philosophical method on the analogy of the mathematical method. The latter is, he claims, mutatis mutandis, the true method of legitimate speculation, i.e. of immanent metaphysics. The one essential difference (as noted by Kant[241]), which has been overlooked by the dogmatists, is that philosophy gains its knowledge from concepts, mathematics from the construction of concepts.

Remain investigations only.[242]—Cf. Prolegomena, § 35.

The analysis of our concepts of objects.[243]—Vaihinger’s interpretation, that the concepts here referred to are those which we “form a priori of things,”[244] seems correct.[245] The rationalists sought to deduce the whole body of rational psychology from the a priori conception of the soul as a simple substance, and of rational theology from the a priori conception of God as the all-perfect Being.

Analytic and synthetic judgments.[246]—“All analytic judgments depend wholly on the law of contradiction, and are in their nature a priori cognitions, whether the concepts that supply them with matter be empirical or not. For the predicate of an affirmative analytic judgment is already contained in the concept of the subject, of which it cannot be denied without contradiction. In the same way its opposite is necessarily denied of the subject in an analytic, but negative, judgment by the same law of contradiction.... For this very reason all analytic judgments are a priori even when the concepts are empirical, as, for example, gold is a yellow metal; for to know this I require no experience beyond my concept of gold as a{60} yellow metal: it is, in fact, the very concept, and I need only analyse it, without looking beyond it elsewhere.... [Synthetic judgments, a posteriori and a priori] agree in this, that they cannot possibly spring solely from the principle of analysis, the law of contradiction. They require a quite different principle. From whatever they may be deduced, the deduction must, it is true, always be in accordance with the principle of contradiction. For that principle must never be violated. But at the same time everything cannot be deduced from it.”[247]

In A 594 = B 622 analytic judgments are also spoken of as identical; but in the Fortschritte[248] this use of terms is criticised:

“Judgments are analytic if their predicate only represents clearly (explicite) what was thought obscurely (implicite) in the concept of the subject, e.g. all bodies are extended. Were we to call such judgments identical only confusion would result. For identical judgments contribute nothing to the clearness of the concept, and that must be the purpose of all judging. Identical judgments are therefore empty, e.g. all bodies are bodily (or to use another term material) beings. Analytic judgments do, indeed, ground themselves upon identity and can be resolved into it; but they are not identical. For they demand analysis and serve for the explanation of the concept. In identical judgments, on the other hand, idem is defined per idem, and nothing at all is explained.”

Vaihinger[249] cites the following contrasted examples of analytic and synthetic judgments:

Analytic.—(a) Substance is that which exists only as subject in which qualities inhere.[250] (b) Every effect has a cause.[5] (c) Everything conditioned presupposes a condition.

Synthetic.—(a) Substance is permanent. (b) Every event has a cause.[251] (c) Everything conditioned presupposes an unconditioned.

B 11-12.—The first half of this paragraph is transcribed practically word for word from the Prolegomena.[252] The second half is a close restatement of an omitted paragraph of the first edition. The chief addition lies in the concluding statement, that “experience is itself a synthetic connection of intuitions.” This is in keeping with statements made in the deduction of the categories in the second edition,[253] and in the paragraph inserted in the proof of the second analogy in the second edition.[254] The x has strangely been omitted in the second{61} edition in reference to empirical judgments, though retained in reference to synthetic a priori judgments.

The proposition: everything which happens has its cause.[255]—As we have already observed,[256] Hume influenced Kant at two distinct periods in his philosophical development—in 1756-1763, and again at some time (not quite definitely datable) after February 1772. The first influence concerned the character of concrete causal judgments; the second related to the causal axiom. Though there are few distinctions which are more important for understanding the Critique than that of the difference between these two questions, it has nowhere been properly emphasised by Kant, and in several of the references to Hume, which occur in the Critique and in the Prolegomena, the two problems are confounded in a most unfortunate manner. The passages in the Introduction[257] are clear and unambiguous; the influence exercised by Hume subsequent to February 1772 is quite adequately stated. The causal axiom claims to be a priori, and is, as Hume asserts, likewise synthetic. Consequently there are only two alternatives, each decisive and far-reaching. Either valid a priori synthesis must, contrary to all previous philosophical belief, be possible, or “everything which we call metaphysics must turn out to be a mere delusion of reason.” The solution of this problem is “a question of life and death to metaphysics.” To this appreciation of Hume, Kant adds criticism. Hume did not sufficiently universalise his problem. Had he done so, he would have recognised that pure mathematics involves a priori synthesis no less necessarily than do the metaphysical disciplines. From denying the possibility of mathematical science “his good sense would probably have saved him.” Hume’s problem, thus viewed, finds its final and complete expression in the formula: How are synthetic a priori judgments possible?

In A 760 = B 788 the account differs in two respects: first, it discusses the metaphysical validity of the causal axiom as well as its intrinsic possibility as a judgment; and secondly, reference is made to the conception of causality as well as to the axiom. The implied criticism of Hume is correspondingly modified. Otherwise, it entirely harmonises with the passages in the Introduction.

“Hume dwelt especially upon the principle of causality, and quite rightly observed that its truth, and even the objective validity of the concept of efficient cause in general, is based on no insight,{62} i.e. on no a priori knowledge, and that its authority cannot therefore be ascribed to its necessity, but merely to its general utility in the course of experience and to a certain subjective necessity which it thereby acquires, and which he entitles custom. From the incapacity of our reason to make use of this principle in any manner that transcends experience he inferred the nullity of all pretensions of reason to advance beyond the empirical.”

Now so far, in these references to Hume, Kant has had in view only the problems of mathematical and physical science and of metaphysics. The problems involved in the possibility of empirical knowledge are left entirely aside. His account of Hume’s position and of his relation to Hume suffers change immediately these latter problems are raised. And unfortunately it is a change for the worse. The various problems treated by Hume are then confounded together, and the issues are somewhat blurred. Let us take the chief passages in which this occurs. In A 764 = B 792 ff. Kant gives the following account of Hume’s argument. Hume, recognising the impossibility of predicting an effect by analysis of the concept of the cause, or of discovering a cause from the concept of the effect, viewed all concrete causal judgments as merely contingent, and therefrom inferred the contingency of the causal axiom. In so doing Hume, Kant argues, confuses the legitimate and purely a priori inference from a given event to some antecedent with the very different inference, possible only through special experience, to a specific cause. Now this is an entire misrepresentation of Hume’s real achievement, and may perhaps be explained, at least in part, as being due to the fact that Kant was acquainted with Hume’s Treatise only through the indirect medium of Beattie’s quotations. Hume committed no such blunder. He clearly recognised the distinction between the problem of the validity of the causal axiom and the problem of the validity of concrete causal judgments. He does not argue from the contingency of concrete causal laws to the contingency of the universal principle, but shows, as Kant himself recognises,[258] that the principle is neither self-evident nor demonstrable a priori. And as necessity cannot be revealed by experience, neither is the principle derivable from that source. Consequently, Hume concludes, it cannot be regarded as objectively valid. It must be due to a subjective instinct or natural belief. (The two problems are similarly confounded by Kant in A 217 = B 264.)

In the Introduction to the Prolegomena there is no such{63} confusion of the two problems, but matters are made even worse by the omission of all reference to Hume’s analysis of the causal axiom. Only Hume’s treatment of the concept of causality is dwelt upon. This is the more unfortunate, and has proved the more misleading, in that it is here that Kant makes his most explicit acknowledgment of his indebtedness to Hume. In §§ 27 ff. of the Prolegomena both problems reappear, but are again confounded. The section is preceded by sentences in which the problem of experience is emphasised; and in keeping with these prefatory remarks, Kant represents “Hume’s crux metaphysicorum” as concerning only the concept of causality (viewed as a synthetic, and professedly a priori, connection between concrete existences). Yet in § 30 the causal axiom is also referred to, and together they are taken as constituting “Hume’s problem.”

Now if we bear in mind that Hume awakened Kant to both problems—how a priori knowledge is possible, and how experience is possible—this confusion can easily be understood. Kant had already in the early ‘sixties studied Hume with profound admiration and respect.[259] In the period subsequent to 1772 this admiration had only deepened; and constantly, as we may believe, Kant had returned with fresh relish to Hume’s masterly analyses of causality and of inductive inference. It is not, therefore, surprising that as the years passed, and as the other elements in Hume’s teaching revealed to him, through the inner growth of his own views, their full worth and significance, he should allow the contribution that had more specifically awakened him to fall into the background, and should, in vague fashion, ascribe to Hume’s teaching as a whole the specific influence which was really due to one particular part. By 1783, the date of the Prolegomena, Kant’s first enthusiasm over the discovery of the fundamental problem of a priori synthesis had somewhat abated, and the problem of experience had more or less taken its place. This would seem to be the reason why in the Prolegomena he thus deals with both aspects of Hume’s problem, and why in so doing he gives a subordinate place to Hume’s treatment of the causal axiom. But though the misunderstanding may be thus accounted for, it must none the less be deplored. For the reader is seriously misled, and much that is central to the Critical philosophy is rendered obscure. The influence which Kant in the Prolegomena thus ascribes to{64} Hume was not that which really awakened him from his dogmatic slumber, but is in part that which he had assimilated at least as early as 1763, and in part that which acted upon him with renewed force when he was struggling (probably between 1778 and 1780) with the problems involved in the deduction of the categories. It was Hume’s treatment of the causal axiom, and that alone, which, at some time subsequent to February 1772, was the really effective influence in producing the Copernican change.[260]

Purely a priori and out of mere concepts.[261]—Vaihinger’s comment seems correct: Kant means only that neither actual experience nor pure intuition can be resorted to. This does not contradict the complementary assertion,[262] that the principle, everything which happens has its cause, can be known a priori, not immediately from the concepts involved in it, but only indirectly[263] through the relation of these concepts to possible experience. “Possible experience,” even though it stands for “something purely contingent,” is itself a concept. Vaihinger[264] quotes Apelt upon this “mysterious” type of judgment.

“Metaphysics is synthetic knowledge from mere concepts, not like mathematics from their construction in intuition, and yet these synthetic propositions cannot be known from bare concepts, i.e. not analytically. The necessity of the connection in those propositions is to be apprehended through thought alone, and yet is not to rest upon the form of thought, the principle of contradiction. The conception of a kind of knowledge which arises from bare concepts, and yet is synthetic, eludes our grasp. The problem is: How can one concept be necessarily connected with another, without also at the same time being contained in it?”

The paragraphs in B 14 to B 17 are almost verbal transcripts from Prolegomena, § 2 c, 2 ff.

Mathematical judgments are one and all (insgesammt) synthetic.[265]—This assertion is carelessly made, and does not represent Kant’s real view. In B 16 he himself recognises the existence of analytic mathematical judgments, but unduly minimises their number and importance.

All mathematical conclusions proceed according to the principle of contradiction.[266]—To the objection made by Paulsen that Kant, in admitting that mathematical judgments can be deduced from others by means of the principle of contradiction,{65} ought consistently to have recognised as synthetic only axioms and principles, Vaihinger replies as follows:[267]

“The proposition—the angles of a triangle are together equal to two right angles—Kant regards as synthetic. It is indeed deduced from the axiom of parallels (with the aid of auxiliary lines), and to that extent is understood in accordance with the principle of contradiction.... The angles in the triangle constitute a special case of the angles in the parallel lines which are intersected by other lines. The principle of contradiction thus serves as vehicle in the deduction, because once the identity of A and A´ is recognised, the predicate b, which belongs to A, must also be ascribed to A´. But the proposition is not for that reason itself analytic in the Kantian sense. In the analytic proposition the predicate is derived from the analysis of the subject concept. But that does not happen in this case. The synthetic proposition can never be derived in and by itself from the principle of contradiction; ... but only with the aid of that principle from other propositions. Besides, in this deduction intuition must always be resorted to; and that makes an essential difference. Without it the identity of A and A´ cannot become known.”

Pure mathematics.[268]—“Pure,” as thus currently used, is opposed only to applied, not to empirical. Kant here arbitrarily reads the latter opposition into it. Under this guise he begs the point in dispute.

7 + 5 = 12.[269]—Though 7 + 5 = 12 expresses an identity or equality, it is an equality of the objects or magnitudes, 7 + 5 and 12, not of the concepts through which we think them.[270] Analysis of the concepts can never reveal this equality. Only by constructing the concepts in intuition can it be recognised by the mind. This example has been already cited in the first edition.[271] It is further elaborated in the Prolegomena, § 2 c, and is here transcribed. Kant’s mode of stating his position is somewhat uncertain. He alternates between “the representation of 7 and 5,” “the representation of the combination of 7 and 5,”[272] and “the concepts 7 and 5.”[273] His view would seem to be that there are three concepts involved. For the concept of 7 we must substitute the intuition of 7 points, for the concept of 5 the intuition of 5 points, and for the concept of their sum the intuitive operation of addition.

Call in the assistance of intuition, for instance our five fingers.[274]—This statement, repeated from the Prolegomena,[275] does not represent Kant’s real position. The views which he has expressed upon the nature of arithmetical science are of the{66} most contradictory character,[276] but to one point he definitely commits himself, namely, that, like geometrical science, it rests, not (as here asserted) upon empirical, but upon pure intuition.[277] Except indirectly, by the reference to larger numbers, Kant here ignores his own important distinction between image and schema.[278] The above statement would also make arithmetic dependent upon space.

Segner: Anfangsgründe der Arithmetik,[279] translated from the Latin, second edition, Halle, 1773.

Natural science (physica) contains synthetic a priori judgments.[280]—There is here a complication to which Vaihinger[281] has been the first to draw attention. In the Prolegomena[282] Kant emphasises the distinction between physics and pure or universal science of nature.[283] The latter treats only the a priori form of nature (i.e. its necessary conformity to law), and is therefore a propaedeutic to physics which involves further empirical factors. For two reasons, however, this universal natural science falls short of its ideal. First, it contains empirical elements, such as the concepts of motion, impenetrability, inertia, etc. Secondly, it refers only to the objects of external sense, and not, as we should expect in a universal science, to natural existences without exception, i.e. to the objects of psychology as well as of physics.[284] But among its principles there are, Kant adds, a few which are purely a priori and possess the universality required: e.g. such propositions as that substance is permanent, and that every event has a cause. Now these are the examples which ought to have been cited in the passage before us. Those actually given fall entirely outside the scope of the Critique. They are treated only in the Metaphysische Anfangsgründe. They belong to the relatively, not to the absolutely, pure science of nature. The source of the confusion Vaihinger again traces to Kant’s failure to hold fast to the important distinction between immanent and transcendent metaphysics.[285] His so-called pure or universal natural science (nature, as above noted, signifying for Kant “all that is”) is really immanent metaphysics, and the propositions in regard to substance and causality ought therefore to be classed as metaphysical. This, indeed, is how they are viewed in the earlier sections of the Prolegomena. The distinction later drawn in § 15 is ignored. Pure natural science is identified with mathematical physics,{67} and the propositions which in § 15 are spoken of as belonging to pure universal natural science are now regarded as metaphysical. “Genuinely metaphysical judgments are one and all synthetic.... For instance, the proposition—everything which in things is substance is permanent—is a synthetic, and properly metaphysical judgment.”[286] In § 5 the principle of causality is also cited as an example of a synthetic a priori judgment in metaphysics. But Kant still omits to draw a distinction between immanent and transcendent metaphysics; and as a consequence his classification of synthetic a priori judgments remains thoroughly confused. They are taken as belonging to three spheres, mathematics, physics (in the relative sense), and metaphysics. The implication is that this threefold distinction corresponds to the threefold division of the Doctrine of Elements into Aesthetic, Analytic, and Dialectic. Yet, as a matter of fact, the propositions of mathematical physics, in so far as they are examples of applied mathematics, are dealt with in the Aesthetic, and in so far as they involve concepts of motion and the like fall entirely outside the scope of the Critique, while the Analytic deals with those metaphysical judgments (such as the principle of causality) which are of immanent employment.[287]

As the new paragraphs in the Introduction to the second edition are transferred without essential modification from the Prolegomena, they are open to the same criticism. To harmonise B 17 with the real teaching of the Critique, it must be entirely recast. Instead of “natural science” (physica) we must read “pure universal natural science [= immanent metaphysics],” and for the examples given we must substitute those principles of substance and causality which are dealt with in the Analytic. The next paragraph deals with metaphysics in its transcendent form, and accordingly states the problem peculiar to the Dialectic.

Metaphysics.[288]—This paragraph deals explicitly only with transcendent judgments, but as the terms used are ambiguous, it is possible that those of immanent metaphysics are also referred to. The paragraph is not taken from the Prolegomena. The corresponding passage[289] in the Prolegomena deals only with the judgments of immanent metaphysics.{68}

The real problem of pure reason is contained in the question: How are synthetic a priori judgments possible?[290]—Cf. above, pp. 26 ff., 33 ff., 43 ff.

David Hume.[291]—Cf. above, pp. 61 ff.

A theoretical knowledge.[292]i.e. Kant explicitly leaves aside the further problem, whether such judgments may not also be possible in the practical (moral) and other spheres.

How is pure natural science possible?[293]—The note which Kant appends shows that he is here taking natural science in the relative sense.[294] The same irrelevant instances are again cited.

As these sciences really exist.[295]—Cf. below, p. 44 ff.

The poor progress which metaphysics has hitherto made.[296]—Cf. Preface to the second edition; Prolegomena, § 4, and A 175 ff.

How is metaphysics as a science possible?[297]—We may now consider how this and the three preceding questions are related to one another and to the various divisions of the Critique.[298] The four subordinate questions within the main problem—How are synthetic a priori judgments possible?—are here stated by Kant as:

1. How is pure mathematics possible?

2. How is pure natural science possible?

3. How is metaphysics as natural disposition possible?

4. How is metaphysics as science possible?

There is little difficulty as regards 1 and 2. The first is dealt with in the Aesthetic, and the second[299] in the Analytic, though, owing to the complexity of the problems, the Aesthetic and Analytic are wider than either query, and cannot be completely separated. Applied mathematics is dealt with in the Analytic as well as in the Aesthetic, and in both the determination of the limits of scientific knowledge is equally important with that of accounting for its positive acquisitions. The third and fourth questions raise all manner of difficulties. Notwithstanding the identical mode of formulation, they do not run on all fours with the two preceding. The first two are taken as referring to actually existing and valid sciences. It is the ground of their objective validity that is sought. But what is investigated in the third question falsely lays claim to the title of science; we can enquire only as to the ground of its subjective possibility. In the fourth question, the problem takes still another form. Kant now seeks to determine whether a new, not yet existing, science of metaphysics is possible, and{69} in what manner it can be validly constructed. The manifoldness of the problems is thus concealed by the fixity of the common formula.[300] Now with what divisions of the Critique are the two last questions connected? It has been suggested[301] that the third question is dealt with in the Dialectic and the fourth in the Methodology, the four questions thus corresponding to the four main divisions of the Critique. But this view is untenable, especially in its view of the fourth question. The division of the Critique is by dichotomy into doctrine of elements and doctrine of methods, the former including the Aesthetic and Logic, and the Logic being again divided into Analytic and Dialectic. Its problems stand in an equally complex subordination; they cannot be isolated from one another, and set merely side by side. Secondly, it has been maintained[302] that the third question is dealt with in the introduction to the Dialectic (in its doctrine of Ideas), and the fourth in the Dialectic proper. This view is fairly satisfactory as regards the third question, but would involve the conclusion that the fourth question refers only to transcendent metaphysics, and that it therefore receives a negative answer. But that is not Kant’s view of metaphysics as a science. The Critique is intended to issue in a new and genuine body of metaphysical teaching.

The key to the whole problem of the four questions is not to be found in the Critique. This section is transcribed from §§ 4-5 of the Prolegomena, and is consequently influenced by the general arrangement of the latter work. This fourfold division was indeed devised for the purposes of the argument of the Prolegomena, which is developed on the analytic method, and for that reason it cannot be reconciled with the very different structure of the Critique. Yet even the Prolegomena suffers from confusion, due[303] to Kant’s failure to distinguish between universal and relative natural science on the one hand, and between immanent and transcendent metaphysics on the other. The four questions do not coincide with those of the Critique. Instead of the third—how is metaphysics as natural disposition possible?—we find: how is metaphysics in general possible? In §§ 4, 5, Kant’s argument is clear and straightforward. Pure mathematical science and mathematical physics are actually existing sciences. The synthetic a priori judgments which they contain must be recognised as valid. Metaphysics makes similar claims. But, as is sufficiently{70} proved by the absence of agreement among philosophers, its professions are without ground. It transgresses the limits of possible experience, and contains only pretended knowledge. This false transcendent metaphysics is refuted in the Dialectic. Kant was, however, equally convinced that an immanent metaphysics is possible, and that its grounds and justification had been successfully given in the Analytic. His problem as formulated in the Prolegomena is accordingly threefold: (1) how are the existing rational sciences, mathematical and physical, possible? (2) in the light of the insight acquired by this investigation, what is the origin and explanation of the existing pretended sciences of transcendent metaphysics? and (3) in what manner can we establish a positive metaphysics that will harmonise with reason’s true vocation? So far all is clear and definite. But the unresolved difficulty, as to the relation in which natural science and immanent metaphysics stand to one another, brings confusion in its train. As already noted,[304] in § 15 natural science is displaced by immanent metaphysics (though not under that name); and as a result the fourth question reduces to the second, and the above threefold problem has to be completely restated. The Prolegomena has, however, already been divided into four parts; and in the last division Kant still continues to treat the fourth question as distinct from that which has been dealt with in the second division, though, as his answer shows, they are essentially the same. The answer given is that metaphysics as a science is possible only in and through the Critique, and that though the whole Critique is required for this purpose, the content of the new science is embodied in the Analytic.

In the second edition of the Critique the confusion between natural science and immanent metaphysics still persists, and a new source of ambiguity is added through the reformulation of the third question. It is now limited to the problem of the subjective origin of metaphysics as a natural disposition. The fourth question has therefore to be widened, so as to include transcendent as well as immanent, the old as well as the new, metaphysics. But save for this one alteration the entire section is inspired by considerations foreign to the Critique; this section, like B 17, must be recast before it will harmonise with the subsequent argument.

Every kind of knowledge is called pure, etc.[305]—These sentences are omitted in the second edition. They have been rendered unnecessary by the further and more adequate definition of “pure” given in B 3 ff.{71}

Reason is the faculty which supplies the principles of knowledge a priori.[306]—This statement should, as Vaihinger points out, be interpreted in the light of A 299 = B 355.

“Reason, like understanding, can be employed in a merely formal, i.e. logical manner, wherein it abstracts from all content of knowledge. But it is also capable of a real use,[307] since it contains within itself the source of certain concepts and principles, which it does not borrow either from the senses or from the understanding.”

Reason is taken in the first of the above meanings. Reason in its real use, when extended so as to include pure sensibility and understanding,[308] is the pure reason referred to in the next sentence of the Critique. A priori is here used to signify the relatively a priori; in the next sentence it denotes the absolutely a priori.

An Organon of pure reason.[309]—What follows, from this point to the middle of the next section, is a good example of Kant’s patchwork method of piecing together old manuscript in the composition of the Critique. There seems to be no way of explaining its bewildering contradictions save by accepting Vaihinger’s[310] conclusion that it consists of three separate accounts, written at different times, and representing different phases in the development of Kant’s views.

I. The first account, beginning with the above words and ending with “already a considerable gain” (schon sehr viel gewonnen ist), is evidently the oldest. It reveals the influence of the Dissertation. It distinguishes:

1. Critique of pure reason ( = Propaedeutic).
2. Organon of pure reason.
3. System of pure reason.

1. Critique is a critical examination (Beurtheilung) of pure reason, its sources and limits. The implication (obscured by the direct relating of Critique to System) is that it prepares the way for the Organon.

2. Organon comprehends all the principles by which pure knowledge can be acquired and actually established.

3. System is the complete application of such an Organon.

This classification is, as Paulsen[311] was the first to remark, an adaptation of the Dissertation standpoint.

II. The second account begins: “I entitle all knowledge transcendental,” but is broken by the third account—from “Such a Critique” to the end of the paragraph—which has{72} been inserted into the middle of it. It is then continued in the next section. It distinguishes:

1. Critique of pure reason.

2. Transcendental philosophy.

1. Critique contains the principles of all a priori synthetical knowledge, tracing an architectonic plan which guarantees the completeness and certainty of all the parts.

2. Transcendental philosophy contains their complete analytic development, and is therefore the system of such knowledge.

III. The third account (“Such a Critique” to end of paragraph) in its main divisions follows the first account: 1. Critique, 2. Organon or Canon, 3. System. But they are now defined in a different manner. Critique is a propaedeutic for the Organon. But Organon, which signifies the totality of the principles through which pure knowledge is attained and extended,[312] may not be possible. In that case the Critique is a preparation only for a Canon, i.e. the totality of the principles of the proper employment of reason.[313] The Organon or Canon, in turn, will render possible a System of the philosophy of pure reason, the former yielding a system in extension of a priori knowledge, the latter a system which defines the limits of a priori knowledge.

It is impossible to reduce these divergencies to a single consistent view. They illustrate the varying sense in which Kant uses the term “metaphysics.” In the first account, even though that account is based on a distinction drawn in the Dissertation, the system of metaphysics is immanent; in the second it is also transcendent; in the third it is neutral.[314]

Propaedeutic.[315]—That the Critique is only propaedeutic to a System of pure reason was later denied by Kant in the following emphatic terms:

“I must here observe that I cannot understand the attempt to ascribe to me the view that I have sought to supply only a Propaedeutic to transcendental philosophy, not the System of this philosophy. Such a view could never have entered my thoughts, for I have myself praised the systematic completeness (das vollendete Ganze) of the pure philosophy in the Critique of Pure Reason as the best mark of its truth.”[316]


Kant thus finally, after much vacillation in his use of the terms, came to the conclusion that Critique, Transcendental Philosophy, and System all coincide. Meantime he has forgotten his own previous and conflicting utterances on this point.

As regards speculation negative only.[317]—“Speculation” here signifies the theoretical, as opposed to the practical.[318] The qualifying phrase is in line with other passages of the second edition, in which it is emphasised that the conclusions of the Critique are positive in their practical (moral) bearing.[319]

Transcendentaltranscendent.[320]—Kant was the first to distinguish between these two terms. In the scholastic period, in which they first appear, they were exactly synonymous, the term transcendent being the more usual. The verb, to transcend, appears in Augustine in its widest metaphysical sense. “Transcende et te ipsum.” “Cuncta corpora transcenderunt [Platonici] quaerentes Deum; omnem animam mutabilesque omnes spiritus transcenderunt quaerentes summum Deum.”[321] The first employment of the term in a more specific or technical sense occurs in a treatise, De natura generis, falsely ascribed to Thomas Aquinas. In this treatise ens, res, aliquid, unum, bonum, verum are entitled transcendentia. To understand the meaning in which the word is here used, we have, it would seem,[322] to take account of the influence exercised upon Aquinas by a mystical work of Arabian origin, entitled De causis. It contained reference to the Neo-Platonic distinction between the Aristotelian categories, which the Neo-Platonists regarded as being derivative, and the more universal concepts, ens, unum, verum, bonum. To these latter concepts Aquinas gave a theological application. Ens pertains to essence, unum to the person of the Father, verum to the person of the Son, bonum to the person of the Holy Ghost. In the De natura generis the number of these supreme concepts is increased to six by the addition of res and aliquid, and as just stated the title transcendentia is also now applied for the first time. In this meaning the term transcendent and its synonym transcendental are of frequent occurrence in Scholastic writings. The transcendentia or transcendentalia are those concepts which so transcend the categories as to be themselves predicable of the categories. They are the “termini vel proprietates rebus omnibus cuiusque generis convenientes.” Thus Duns Scotus speaks of ens as the{74} highest of the “transcendental” concepts. The term also occurs in a more or less similar sense in the writings of Campanella, Giordano Bruno, Francis Bacon, and Spinoza. The last named gives a psychological explanation of the “termini Transcendentales ... ut Ens, Res, Aliquid” as standing for ideas that are in the highest degree confused owing to the multiplicity of the images which have neutralised one another in the process of their generation.[323] Berkeley also speaks of the “transcendental maxims” which lie outside the field of mathematical enquiry, but which influence all the particular sciences.[324] Evidently the term has become generalised beyond its stricter scholastic meaning. Lambert employs transcendent in an even looser sense to signify concepts which represent what is common to both the corporeal and the intellectual world.[325] We may, indeed, assert that in Kant’s time the terms transcendent and transcendental, while still remaining synonymous, and though used on the lines of their original Scholastic connotation, had lost all definiteness of meaning and all usefulness of application. Kant took advantage of this situation to distinguish sharply between them, and to impose upon each a meaning suitable to his new Critical teaching.

“Transcendental” is primarily employed by Kant as a name for a certain kind of knowledge. Transcendental knowledge is knowledge not of objects, but of the nature and conditions of our a priori cognition of them. In other words, a priori knowledge must not be asserted, simply because it is a priori, to be transcendental; this title applies only to such knowledge as constitutes a theory or science of the a priori.[326] Transcendental knowledge and transcendental philosophy must therefore be taken as coinciding; and as thus coincident, they signify the science of the possibility, nature, and limits of a priori knowledge. The term similarly applies to the subdivisions of the Critique. The Aesthetic is transcendental in that it establishes the a priori character of the forms of sensibility; the Analytic in that it determines the a priori principles of understanding, and the part which they play in the constitution of knowledge; the Dialectic in that it defines and limits the a priori Ideas of Reason, to the{75} perverting power of which all false metaphysics is due. That this is the primary and fundamental meaning common to the various uses of the term is constantly overlooked by Max Müller. Thus in A 15 = B 30 he translates transcendentale Sinnenlehre “doctrine of transcendental sense” instead of as “transcendental doctrine of sense.” In transforming transcendentale Elementarlehre into “elements of transcendentalism” he avoids the above error, but only by inventing a word which has no place in Kant’s own terminology.

But later in the Critique Kant employs the term transcendental in a second sense, namely, to denote the a priori factors in knowledge. All representations which are a priori and yet are applicable to objects are transcendental. The term is then defined through its distinction from the empirical on the one hand, and from the transcendent on the other. An intuition or conception is transcendental when it originates in pure reason, and yet at the same time goes to constitute an a priori knowledge of objects. The contrast between the transcendental and the transcendent, as similarly determined upon by Kant, is equally fundamental, but is of quite different character. That is transcendent which lies entirely beyond experience; whereas the transcendental signifies those a priori elements which underlie experience as its necessary conditions. The transcendent is always unknowable. The transcendental is that which by conditioning experience renders all knowledge, whether a priori or empirical, possible. The direct opposite of the transcendent is the immanent, which as such includes both the transcendental and the empirical. Thus while Kant employs the term transcendental in a very special sense which he has himself arbitrarily determined, he returns to the original etymological meaning of the term transcendent. It gains a specifically Critical meaning only through being used to expound the doctrine that all knowledge is limited to sense-experience. The attempt to find some similar etymological justification for Kant’s use of the term transcendental has led Schopenhauer and Kuno Fischer to assert that Kant entitles his philosophy transcendental because it transcends both the dogmatism and the scepticism of all previous systems![327] Another attempt has been made by Stirling[328] and Watson,[329] who assert, at least by implication, that the transcendental is a species of the transcendent, in that while the latter transcends the scope of experience, the {76}former transcends its sense-content. Kant himself, however, nowhere attempts to justify his use of the term by any such argument.

A third meaning of the term transcendental arises through its extension from the a priori intuitions and concepts to the processes and faculties to which they are supposed to be due. Thus Kant speaks of the transcendental syntheses of apprehension, reproduction, and recognition, and of the transcendental faculties of imagination and understanding. In this sense the transcendental becomes a title for the conditions which render experience possible. And inasmuch as processes and faculties can hardly be entitled a priori, Kant has in this third application of the term departed still further from his first definition of it.[330]

The distinction between the transcendental and the transcendent may be illustrated by reference to the Ideas of reason. Regarded as regulative only, i.e. merely as ideals which inspire the understanding in the pursuit of knowledge, they are transcendental. Interpreted as constitutive, i.e. as representing absolute realities, they are transcendent. Yet, despite the fundamental character of this distinction, so careless is Kant in the use of his technical terms that he also employs transcendental as exactly equivalent in meaning to transcendent. This is of constant occurrence, but only two instances need here be cited. In the important phrase “transcendental ideality of space and time” the term transcendental is used in place of the term transcendent. For what Kant is asserting is that judged from a transcendent point of view, i.e. from the point of view of the thing in itself, space is only subjectively real.[331] The phrase is indeed easily capable of the orthodox interpretation, but, as the context clearly shows, that is not the way in which it is actually being used by Kant. Another equally surprising example is to be found in the title “transcendental dialectic.” Though it is defined in A 63-4 = B 88 in correct fashion, in A 297 = B 354 and A 308-9 = B 365-6 it is interpreted as treating of the illusion involved in transcendent judgments, and so virtually as meaning transcendent dialectic.[332]

Not a Critique of books and systems.[333]—Kant here inserts a statement from the omitted Preface to the first edition.[334] He now adds that the Critique will supply a criterion for the valuation of all other systems.{77}

A 13 = B 27.—Kant’s reason for omitting the title of Section II in the second edition was no doubt its inconsistency with the assertion of its opening sentence, viz. that the Critique is not transcendental philosophy, but only a preparation for it. Instead of it, Kant has introduced the more appropriate heading placed over the preceding paragraph.

The highest principles of morals do not belong to transcendental philosophy.[335]—Cf. A 801 = B 829. The alteration made in this passage in the second edition[336] indicates a transition towards the opposite view which Kant developed in the Critique of Practical Reason.[337]

The division of this science.[338]—Kant in this paragraph alternates in the most bewildering fashion between the Critique and Transcendental Philosophy. In this first sentence the Critique seems to be referred to. Later it is Transcendental Philosophy that is spoken of.

Doctrine of Elements and Doctrine of Methods.[339]—Cf. A 707 ff. = B 735 ff., and below, pp. 438, 563.

Two stems, sensibility and understanding, which may perhaps spring from a common root.[340]—Kant sometimes seems to suggest[341] that imagination is this common root. It belongs both to sensibility and to understanding, and is passive as well as spontaneous. But when so viewed, imagination is virtually regarded as an unknown supersensuous power, “concealed in the depths of the soul.”[342] The supersensuous is the point of union of our disparate human faculties, as well as of nature and freedom, mechanism and teleology.

The transcendental doctrine of sense would necessarily constitute the first part of the Science of Elements.[343]—“Necessarily constitute the first part” translates zum ersten Theile gehören müssen. This Vaihinger explains as an archaic mode of expression, equivalent to ausmachen. The point is important because, if translated quite literally, it might seem to conflict with the division actually followed, and to support the alternative division given in the Critique of Practical Reason. The first Critique is divided thus:{78}

I. Doctrine of Elements.
      1. Aesthetic.
      2. Logic.
          (a) Analytic.
         (b) Dialectic.
II. Doctrine of Methods.

In the Critique of Practical Reason[344] a much more satisfactory division is suggested:

I. Doctrine of Elements.
      1. Analytic.
          (a) Aesthetic (Sense).
          (b) Logic (Understanding).
      2. Dialectic.
II. Doctrine of Methods.

The first division rests on somewhat irrelevant distinctions derived from the traditional logic; the other is more directly inspired by the distinctions which naturally belong to Kant’s own philosophical system.{79}




THE Aesthetic opens with a series of definitions. Intuition (Anschauung) is knowledge (Erkenntnis) which is in immediate relation to objects (sich auf Gegenstände unmittelbar bezieht). Each term in this definition calls for comment. Anschauung etymologically applies only to visual sensation. Kant extends it to cover sensations of all the senses. The current term was Empfindung. Kant’s reason for introducing the term intuition in place of sensation was evidently the fact that the latter could not be made to cover space and time. We can speak of pure intuitions, but not of pure sensations. Knowledge is used in a very wide sense, not strictly consistent with A 50-1 = B 74-5.[345] The phrase sich bezieht is quite indefinite and ambiguous. Its meaning will depend upon the interpretation of its context. Object is used in its widest and most indefinite meaning. It may be taken as signifying content (Inhalt, a term which does not occur in this passage, but which Kant elsewhere employs[346]). That, at least, is the meaning which best fits the context. For when Kant adds that intuition relates itself to objects immediately, it becomes clear that he has in mind its distinction from conception (Begriff) which as expressing the universal is related to objects only indirectly, representing some one or more attributes of the given objects. Ultimately the whole content of conception must be given.[347] The phrase “relates itself to objects” may, therefore, be paraphrased “has some content, such as red or cold, as its immediate object.” Through the content of intuition the whole material of thought is supplied.{80} Intuition in itself is blind, but not empty. “Thoughts without content are empty; intuitions without concepts are blind.”[348]

But the phrase “is in relation to objects” has also for Kant a second meaning, implied in the above, but supplementary to it. As he states in the very next sentence, intuition can have an object, meaning thereby a content, only in so far as that content is given. The material of thought must be supplied; it cannot be invented.[349] The only mode, however, in which it can be supplied, at least to the human mind, is through the affecting of the mind by “the object.” This is an excellent instance of Kant’s careless mode of expressing himself. In the first part of the sentence object means object of intuition. In the latter part it signifies the cause of intuition. And on Kant’s view the two cannot coincide. The object which affects the mind is independently real; the immediate object of the intuition is a sense-content, which Kant, following the universally accepted view of his time, regards as purely subjective. The term object is thus used in two quite distinct meanings within one and the same sentence.

Kant’s definition of intuition, when stated quite explicitly, and cleared of all ambiguity, is therefore as follows. Intuition is the immediate apprehension of a content which as given is due to the action of an independently real object upon the mind. This definition is obviously not meant to be a description of intuition as it presents itself to introspection, but to be a reflective statement of its indispensable conditions. Also it has in view only empirical intuitions. It does not cover the pure intuitions space and time.[350] Though space and time are given, and though each possesses an intrinsic content, these contents are not due to the action of objects upon the sensibility.

“An intuition is such a representation as immediately depends upon the presence of the object. Hence it seems impossible originally to intuit a priori because intuition would in that event take place without either a former or a present object to refer to, and by consequence could not be intuition.”[351]

This interpretation is borne out by Kant’s answer to Beck when the latter objected that only through subsumption under the categories can a representation become objective. Kant replies in a marginal note, the meaning of which, though difficult to decipher, admits of a fairly definite interpretation.{81}

“The determining of a concept through intuition so as to yield knowledge of the object falls within the province of the faculty of judgment, but not the relation of the intuition to an object in general [i.e. the view of it as having a content which is given and which is therefore due to some object], for that is merely the logical use of the representation, whereby it is thought as falling within the province of knowledge. On the other hand, if this single representation is related only to the subject, the use is aesthetic (feeling), and the representation cannot be an act of knowledge.”[352]

Mind (Gemüt) is a neutral term without metaphysical implications.[353] It is practically equivalent to the term which is substituted for it in the next paragraph, power of representation (Vorstellungsfähigkeit). Representation (Vorstellung) Kant employs in the widest possible meaning. It covers any and every cognitive state. The definition here given of sensibility—“the capacity (receptivity) to obtain representations through the mode in which we are affected by objects”—is taken directly over from the Dissertation.[354] In this definition, as in that of intuition, Kant, without argument or question, postulates the existence of independently existing objects. The existence of given sensations presupposes the existence of things in themselves. Sensibility is spoken of as the source both of objects and of intuitions. This is legitimate since object and intuition mutually imply one another; the latter is the apprehension of the former. By “objects” is obviously meant what in the third paragraph is called the matter of appearances, i.e. sensations in their objective aspect, as qualities or contents. The term “object” is similarly employed in the last line of this first paragraph.

Understanding (Verstand) is defined only in its logical or discursive employment. Kant wisely defers all reference to its more fundamental synthetic activities. In us (bei uns) is an indirect reference to the possibility of intellectual (non-sensuous) intuition which is further developed in other parts of the Aesthetic.[355] Sensuous intuition is due to affection by an object. In intellectual intuition the mind must produce the object in the act of apprehending it.[356]

Kant’s definition of intuition applies, as already noted, only to empirical intuition. He proceeds[357] to define the relation in which sensation (Empfindung) stands to empirical intuition. What he here says amounts to the assertion that through sensation intuition acquires its object, i.e. that sensation{82} is the content of intuition. And that being so, it is also through sensation that empirical intuition acquires its relation to the object (= thing in itself) which causes it. (That would seem to be the meaning of the ambiguous second sentence; but it still remains uncertain whether the opposition intended is to pure or to intellectual intuition.) If this interpretation of the paragraph be correct, sensation is counted as belonging exclusively to the content side of subjective apprehension. But Kant views sensation in an even more definite manner than he here indicates. Though sensation is given, it likewise involves a reaction of the mind.

“Whatever is sensuous in knowledge depends upon the subject’s peculiar nature, in so far as it is capable of this or that modification upon the presence of the object.”[358]

Thus for Kant sensation is a modification or state of the subject, produced by affection through an object. The affection produces a modification or state of the subject, and this subjective modification is the sensation.

“Sensation is a perception [Perception] which relates itself solely to the subject as the modification of its state.”[359]

This view of sensation, as subjective, was universally held in Kant’s day. He accepts it without argument or question. That it could possibly be challenged never seems to have occurred to him. He is equally convinced that it establishes the existence of an actually present object.

“Sensation argues the presence of something, but depends as to its quality upon the nature of the subject.”[360] “Sensation presupposes the actual presence of the object.”[361]

Kant’s view of sensation, as developed in the Aesthetic,[362] thus involves three points: (1) It must be counted as belonging to the content side of mental apprehension. (2) Though a quality or content, it is purely subjective, depending upon the nature of our sensibility. (3) It is due to the action of some object upon the sensibility.

Kant distinguishes between sensation (Empfindung) and feeling (Gefühl).[363] It had been usual to employ them as synonyms.{83}

“We understand by the word sensation an objective representation of the senses; and in order to preclude the danger of being misunderstood, we shall denote that which must always remain merely subjective and can constitute absolutely no representation of an object by the ordinary (sonst üblichen) term feeling.”[364]

Appearance (Erscheinung) is here defined as the undetermined object of an intuition. By undetermined object is meant, as we have seen, the object in so far as it consists of the given sense contents. When these contents are interpreted through the categories they become phenomena.

“Appearances so far as they are thought as objects according to the unity of the categories are called phenomena.”[365]

But this distinction between appearance and phenomenon is not held to by Kant. He more usually speaks of the categorised objects as appearances. The term phenomenon is of comparatively rare occurrence in the Critique. This has been concealed from English readers, as both Meiklejohn and Max Müller almost invariably translate Erscheinung phenomenon. The statement that appearance is the object of an empirical intuition raises a very fundamental and difficult question, namely, as to the relation in which representation stands to the represented.[366] Frequently Kant’s argument implies this distinction, yet constantly he speaks and argues as if it were non-existent. We have to recognise two tendencies in Kant, subjectivist and phenomenalist.[367] When the former tendency is in the ascendent, he regards all appearances, all phenomena, all empirical objects, as representations, modifications of the sensibility, merely subjective. When, on the other hand, his thinking is dominated by the latter tendency, appearances gain an existence independent of the individual mind. They are known through subjective representations, but must not be directly equated with them. They have a genuine objectivity. To this distinction, and its consequences, we shall have frequent occasion to return.

The phenomenalist standpoint is dominant in these first two paragraphs of the Aesthetic, and it finds still more pronounced{84} expression in the opening of the third paragraph. “That in the appearances which corresponds (correspondirt) to sensation, I call its matter.” This sentence, through the use of the term corresponds, clearly implies a distinction between sensation and the real object apprehended in and through it. That, in turn, involves a threefold distinction, between sensation as subjective content (= appearance in the strict sense), the real enduring object in space (= phenomenon, the categorised object, appearance in its wider and more usual sense), and the thing in itself.[368] Yet in the immediately following sentence Kant says that “the matter of all appearance is given a posteriori.” By “matter of appearance” Kant must there mean sensations, for they alone are given a posteriori.[369] On this view the phenomena or empirical objects reduce to, and consist of, sensations. The intermediate term of the above threefold distinction is eliminated. The matter of appearance does not correspond to, but itself is, sensation. Thus in these successive sentences the two conflicting tendencies of Kant’s teaching find verbal expression. They intervene even in the preliminary definition of his terms. This fundamental conflict cannot, however, be profitably discussed at this stage.

The manifold of appearance (das Mannichfaltige der Erscheinung). The meaning to be assigned to this phrase must depend upon the settlement of the above question.[370] But in this passage it allows only of a subjectivist interpretation, whereby sensations are appearance. The given sensations as such constitute a manifold; as objects in space they are already ordered. Kant’s more usual phrase is “the manifold of intuition.” His adoption of the term “manifold” (the varia of the Dissertation) expresses his conviction that synthesis is indispensable for all knowledge, and also his correlative view that nothing absolutely simple can be apprehended in sense-experience. By the manifold Kant does not mean, however, as some of his commentators would seem to imply, the chaotic or disordered. The emphasis is on manifoldness or plurality, as calling for reduction to unity and system. The unity has to be found in it, not introduced into it forcibly from the outside. The manifold has to be interpreted, even though the principles of interpretation may originate independently of it. Though, for instance, the{85} manifold as given is not in space and time, the specific space and time relations assigned by us are determined for us by the inherent nature of the manifold itself.[371]

The form of appearance is defined—if the definition given in the first edition be translated literally—as “that which causes (dasjenige, welches macht dass) the manifold of appearance to be intuited as ordered in certain relations.” This phrase is employed by Kant in other connections, and, as Vaihinger points out,[372] need not necessarily indicate activity. “Sensation is that in our knowledge which causes it to be called a posteriori knowledge.”[373] In the second edition Kant altered the text from “geordnet angeschaut wird” to “geordnet werden kann.” The reason probably was that the first edition’s wording might seem to imply that the form is (as the Dissertation taught) capable in and by itself of ordering the manifold. Throughout the second edition Kant makes more prominent the part which understanding plays in the apprehension of space.[374]

This distinction between matter and form is central in Kant’s system.[375] As he himself says:

“These are two conceptions which underlie all other reflection, so inseparably are they bound up with all employment of the understanding. The one [matter] signifies the determinable in general, the other [form] its determination.”[376]

On the side of matter falls the manifold, given, empirical, contingent material of sense; on the side of form fall the unifying, a priori, synthetic, relational instruments of sensibility and thought. For Kant these latter are no mere abstractions, capable of being distinguished by the mind; they differ from the matter of experience in nature, in function, and in origin. Upon this dualistic mode of conceiving the two factors depends the strength as well as the weakness of his position. To its perverting influence most of the unsatisfactory features of his doctrine of space and time can be directly traced. But to it is also due his appreciation of the new Critical problems, with their revolutionary consequences, as developed in the Analytic.

Kant proceeds to argue: (a) that the distinction is between two elements of fundamentally different nature and origin. The matter is given a posteriori in sensation; the form, as distinct from all sensation, must lie ready a priori in the mind. (b) Kant also argues that form, because of its separate origin, is{86} capable of being contemplated apart from all sensation. The above statements rest upon the unexpressed assumption that sensations have no spatial attributes of any kind.[377] In themselves they have only intensive, not extensive, magnitude.[378] Kant assumes this without question, and without the least attempt at proof.[379] The assumption appears in Kant’s writings as early as 1768 as a self-evident principle;[380] and throughout the Critique is treated as a premiss for argument, never as a statement calling for proof. The only kind of supporting argument which is even indirectly suggested by Kant is that space cannot by itself act upon the senses.[381] This would seem to be his meaning when he declares[382] that it is no object, but only an ens imaginarium. “Space is no object of the senses.”[383] Such argument, however, presupposes that space can be conceived apart from objects. It is no proof that an extended object may not yield extended sensations. Kant completely ignores the possibility that formal relations may be given in and with the sensations. If our sensibility, in consequence of the action of objects upon it, is able to generate qualitative{87} sensations, why, as Vaihinger very pertinently enquires,[384] should it be denied the power of also producing, in consequence of these same causes, impressions of quantitative formal nature? Sensations, on Kant’s view, are the product of mind much more than of objects. Why, then, may not space itself be sensational?[385] From the point of view of empirical science there is no such radical difference between cause and effect in the latter case as exists in the former. As Herbert Spencer has remarked,[386] Kant makes the enormous assumption

“...that no differences among our sensations are determined by any differences in the non-ego (for to say that they are so determined is to say that the form under which the non-ego exists produces an effect upon the ego); and as it similarly follows that the order of coexistence and sequence among these sensations is not determined by any order in the non-ego; we are compelled to conclude that all these differences and changes in the ego are self-determined.”

Kant’s argument in the Dissertation is exactly of this nature.

“Objects do not strike the senses by their form. In order, therefore, that the various impressions from the object acting on the sense may coalesce into some whole of representation, there is required an inner principle of the mind through which in accordance with stable and innate laws that manifold may take on some form.”[387]

In the paragraph before us Kant may, at first sight, seem to offer an argument. He is really only restating his premiss. “That wherein alone sensations can be arranged (sich ordnen[388]) and placed in a certain form cannot itself again be sensation.” Now, of course, if the term sensation is to be limited to the sense qualities, i.e. to content or matter, conceived as existing apart from all formal relations, the formal elements cannot possibly be sensational. The legitimacy of{88} that limitation is, however, the question at issue. It cannot be thus decided by an arbitrary verbal distinction.

“Were the contention that the relations of sensations are not themselves sensed correct, the inference to the pure apriority of the form of our perception would be inevitable. For sensation is the sole form of interaction between consciousness and reality.... But that contention is false. The relations of sensations, their determined coexistence and sequence, impress consciousness, just as do the sensations. We feel this impression in the compulsion which the determinateness of the empirical manifolds lays upon the perceiving consciousness. The mere affection of consciousness by these relations does not, indeed, by itself suffice for their apprehension; but neither does it suffice for the apprehension of the sensation itself. Thus there is in these respects no difference between the matter and the form of appearance.”[389]

In this way, then, by means of his definition of sensation, Kant surreptitiously introduces his fundamental assumption. That assumption reappears as the conclusion that since the form of appearance cannot be sensation, it does not arise through the action of the object, and consequently must be a priori. Though the paragraph seems to offer an argument in support of the apriority of space and time, it is found on examination merely to unfold a position adopted without the slightest attempt at proof.[390]

The form of appearance must lie ready in the mind.[391]—Comment upon this, in order to be adequate, had best take the form of a systematic discussion of Kant’s views, here and elsewhere, of space as an a priori form of intuition. As already stated, the definition which Kant gives of intuition—as knowledge which stands in immediate relation to objects—applies only to empirical intuition. Though by the term object Kant, in so far as he is definite, means content, that content is such as can arise only through the action of some independent object upon the sensibility. In other words, the content apprehended must be sensuous. Now such a view of intuition obviously does not apply to pure intuition. As the concluding line of the paragraph before us states, pure intuition “can be contemplated in separation from all sensation;” and as the next paragraph adds, it exists in the mind “without any actual object of the senses.” Yet Kant does not mean to imply that it is without content of any kind. “This pure{89} form of sensibility may also itself be called pure intuition.”[392] “It can be known before all actual perception, and for that reason is called pure intuition.”[393] Though, therefore, pure intuition has an intrinsic content, and is the immediate apprehension of that content, it stands in no relation to any actual independent object. The content as well as the form is a priori. That, however, raises wider questions, and these we must now discuss.

Here, as in most of his fundamental positions, Kant entertains divergent and mutually contradictory doctrines. Only in his later utterances does he in any degree commit himself to one consistent view. The position to which he finally inclines must not, however, be allowed to dominate the interpretation of his earlier statements. The Aesthetic calls for its own separate exegesis, quite as if it formed by itself an independent work. Its problems are discussed from a standpoint more or less peculiar to itself. The commentator has the twofold task of stating its argumentation both in its conflict with, and in its relation to, the other parts of the Critique.

One essential difference between Kant’s earlier and later treatments of space is that in his earlier utterances it is viewed almost exclusively as a psychological a priori. The logical aspect of the problem first receives anything like adequate recognition in the Analytic. If we keep this important fact in mind, two distinct and contradictory views of the psychological nature of space intuition can be traced throughout the Aesthetic. On one view, it antedates experience as an actual, completed, conscious intuition. On the other view, it precedes experience only as a potential disposition. We rule ourselves out from understanding Kant’s most explicit utterances if we refuse to recognise the existence of both views. Kant’s commentators have too frequently shut their eyes to the first view, and have then blamed Kant for using misleading expressions. It is always safer to take Kant quite literally. He nearly always means exactly what he says at the time when he says it. Frequently he holds views which run completely counter to present-day psychology, and on several occasions he flatly contradicts what he has with equal emphasis maintained in other contexts. The aspects of Kant’s problems are so complex and various, and he is so preoccupied in doing complete justice{90} to each in turn, that the question of the mutual consistency of his results is much less considered than is ideally desirable.

The two views can be more explicitly formulated. The first view alone is straightforward and unambiguous. Space lies ready (liegt bereit) in the mind, i.e. it does not arise. Prior even to sense-experience it exists as a conscious intuition. For this reason it can be contemplated apart from all sensation. It still remains when all sense content is thought away, and yet is not a mere form. In independence of the sensuous manifold it possesses a pure manifold of its own. The ground thesis of the second view—that space, prior to sense-experience, exists only as a permanent endowment of the mind—is likewise unambiguous. But in its development Kant throws consistency to the winds. The possible ways in which, on the second view, consciousness of space may be gained, can be tabulated as follows:

(a) By reflection upon the activity of the mind in the
construction of experience, yielding the intuition of a pure
manifold; or (b) by reflection upon the space-endowed
products of experience.[394] The latter mode of reflection may reveal:
    (α) A pure manifold distinct from the manifold of sense; or
    (β) Space as a form of the sensuous manifold.

There are thus three different ways (a, α, β) in which the second view can be developed: (a) represents the view of the Dissertation (1770), of the reply to Eberhard (1790), and of those parts of the first edition’s deduction of the categories which are of very early origin; (α) represents the final standpoint of the Analytic; (β), the prevailing view of the present day, is nowhere accepted by Kant.[395]

Kant’s utterances in the Aesthetic are all of them coloured by the first main view. We can best approach them by way of the contrasted teaching of the Dissertation of 1770. The teaching there formulated practically coincides, as above stated, with (a) of the second main view. Space, he maintains, is neither innate nor acquired from sense-experience.

“Certainly both conceptions [of time and of space] are undoubtedly acquired, not indeed by abstraction from our sensations of objects (for sensation gives the matter, not the form of human{91} cognition), but from the mind’s own action in co-ordinating its sensations in accordance with unchanging laws. Each represents, as it were, an immutable type, and so can be known intuitively. Sensations excite this act of mind but do not contribute to the intuition. There is here nothing innate except this law of the mind according to which it conjoins in a certain manner the sensations derived from the presence of some object.”[396]

How this view is to be reconciled with the contention, no less explicitly maintained,[397] that space is not only a form of intuition but itself a pure intuition, Kant does not make clear. Reflection upon an activity of the mind may yield the representation of space as a form; it is difficult to comprehend how it should also yield an a priori content.

Kant nowhere in the Critique directly discusses the question whether the representation of space is innate or acquired. Such suggestions as occur refer (with the solitary exceptions of A 196 = B 241 and B 166 ff.)[398] only to the categories,[399] or as in the Prolegomena[400] to the Ideas of reason. But in 1790 Kant in his reply to Eberhard[401] again formulates the view of the Dissertation. The Critique allows, he there says, of no innate representations. All, without exception, are acquired. But of certain representations there is an original acquisition (ursprüngliche Erwerbung). Their ground (Grund) is inborn. In the case of space this ground is the mind’s peculiar capacity for acquiring sensations in accordance with its subjective constitution.[402]

“This first formal ground is alone inborn, not the space representation itself. For it always requires impressions to determine the faculty of knowledge to the representation of an object (which in every case is its own action). Thus arises the formal intuition, which we name space, as an originally acquired representation (the form of outer objects in general), the ground of which (as mere receptivity) is likewise inborn, and the acquisition of which long antedates the determinate conception of things which are in accordance with this form.”[403]

That last remark is confusing. Kant cannot mean that the representation of space is acquired prior to sense-experience, but only that since the mind gains it by reflection upon its own activity, it is among the first things to be{92} apprehended—an extremely questionable assertion, could the premisses be granted. If “the determinate conception of things” comes late, still later must come the determinate conception of anything so abstract as pure space. The above passage thus repeats without essential modification the teaching of the Dissertation, and is open to the same objections. This teaching coincides with that of Leibniz in his Nouveaux Essais; and in formulating it in the Dissertation Kant was very probably influenced by Leibniz. Though it is an improvement upon the more extreme forms of the Cartesian doctrine of innate ideas, it does not go sufficiently far.

Now while Kant thus in 1770 and in 1790 so emphatically teaches that the representation of space is not innate, he none the less, in the intermediate period represented by the Aesthetic, would seem to maintain the reactionary view. Space is no mere potential disposition. As a conscious representation it lies ready in the mind. What, then, were the causes which constrained Kant to go back upon his own better views and to adopt so retrograde a position? The answer must be conjectural, but may perhaps be found in the other main point in which the teaching of the Aesthetic is distinguished from that of the Dissertation. Throughout the Critique Kant insists that space is a form of receptivity. It is given to the mind. It has nothing to do with spontaneity or understanding, and therefore cannot be acquired by reflection upon any activity of the mind. But neither can it, as a priori, be acquired from without. Consequently it cannot be acquired at all. But if given, and yet not acquired, it must as a representation lie ready in the mind from the very birth of consciousness. Constrained by such reasoning, Kant views it as given in all its completeness just as truly as is a sensation of colour or sound. This conclusion may not be satisfactory. Kant’s candid recognition of it is, however, greatly preferable to the blurring of the issue by most of his commentators.

Kant came, no doubt, to the more consistent position of the Aesthetic chiefly through further reflection upon the arguments of the Dissertation,[404] and especially by recognition of the fact that though reflection upon an activity of the mind may be regarded as yielding a form of intuition, it can hardly be capable of yielding a pure manifold which can be substituted for, and take the place of, the manifold of sense. There are for Kant only two ways of escape from this unhappy quandary: (a) Either he must return to the Dissertation position, and admit that the mind is active in the construction of space.{93} This he does in the 1790 reply to Eberhard, but only by misrepresenting his own teaching in the Critique. In order consistently to maintain that space is acquired by reflection upon an activity of the mind, he would have to recast the entire Aesthetic, as well as much of the Analytic, and to do so in ways which cannot genuinely harmonise with the main tendencies of his teaching.[405] (b) No such obstacle lay in the way of an alternative modification of his position. Kant might very easily have given up the contention that space is a pure intuition. If he had been willing to recognise that the sole possible manifold of intuition is sensuous, he could then have maintained that though space is innate as a potential form of receptivity, it is acquired only through reflection upon the space-endowed products of sensibility. So obvious are the advantages of this position, so completely does it harmonise with the facts of experience and with the teaching of modern psychology, and so obscure are the various passages in which Kant touches on this central issue, that many of his most competent commentators are prepared to regard it as being the actual teaching of the Critique. The evidence[406] seems to me, however, to refute this interpretation of Kant’s position. The traditional, Cartesian, semi-mystical worship of mathematical truth, as altogether independent of the contingencies of sense-experience, and as a body of knowledge absolutely distinct in origin from the merely empirical sciences, influences Kant’s thinking even at the very moment when he is maintaining, in opposition to the Cartesians, that its subject matter is a merely subjective intuition. Kant, as it would seem, still maintains that there is a pure manifold of intuition distinct from the manifold of sense; and so by the inevitable logic of his thought is constrained to view space as innate in conscious form. This is not, of course, a conclusion which he could permanently stand by, but its elimination would have involved a more radical revision of his whole view of pure intuition and of mathematical science than he was willing to undertake. Though in the Analytic he has come to recognise[407] that it is acquired by reflection upon objects, to the end he would seem to persist in the difficult contention that such reflection yields a pure manifold distinct {94}from the manifold of sense.[408] His belief that mathematical science is based upon pure intuition prevented him from recognising that though space may be a pure form of intuition, it can never by itself constitute a complete intuition. Its sole possible content is the manifold of sense. But even apart from the fact that our apprehension of space is always empirically conditioned, Kant’s view of mathematical propositions as grounded in intuition is, as already observed, not itself tenable. For though intuitions may perhaps be the ultimate subject matter of geometry, concepts are its sole possible instruments. Intuitions yield scientific insight in exact proportion to our powers of restating their complex content in the terms of abstract thought. Until the evidence which they supply has been thus intellectually tested and defined, they cannot be accepted as justifying even the simplest proposition.[409]

The complicated ambiguities of Kant’s treatment of space may be illustrated and further clarified by discussion of another difficulty. Is space a totum analyticum or a totum syntheticum? Does the whole precondition the parts, or does it arise through combination of the parts? Or to ask another but connected question, do we intuit infinitude, or is it conceptually apprehended only as the presupposition of our limited intuitions? To these questions diametrically opposite answers can be cited from the Critique. As we have above noted, Kant teaches in the Aesthetic that space is given as a whole, and that the parts arise only by limitation of it. But in A 162 = B 203 we find him also teaching that a magnitude is to be entitled extensive

“...when the representation of the parts makes possible, and therefore necessarily precedes, the representation of the whole. I cannot represent to myself a line, however small, without drawing it in thought, i.e. generating from a point all its parts one after another, and thus for the first time recording this intuition.”[410]

He adds in the second edition[411] that extensive magnitude cannot be apprehended save through a “synthesis of the manifold,” a “combination of the homogeneous.”

The note which Kant appends to B 136 is a very strange combination of both views. It first of all reaffirms the doctrine of the Aesthetic that space and time are not concepts, but intuitions within which as in a unity a multitude of representations are contained; and then proceeds to argue that space{95} and time, as thus composite, must presuppose an antecedent synthesis. In A 505 = B 533 we find a similar attempt to combine both assertions.

“The parts of a given appearance are first given through and in the regress of decomposing synthesis (decomponirenden Synthesis).”

The clash of conflicting tenets which Kant is striving to reconcile could hardly find more fitting expression than in this assertion of an analytic synthesis. The same conflict appears, though in a less violent form, in A 438 = B 466.

“Space should properly be called not compositum but totum, since its parts are possible only in the whole, not the whole through the parts. It might, indeed, be said to be a compositum that is ideale, but not reale. That, however, is a mere subtlety.”[412]

The arguments by which Kant proves space to be an a priori intuition rest upon the view that space is given as infinite, and that its parts arise through limitation of this prior-existent whole. But a principle absolutely fundamental to the entire Critique is the counter principle, that all analysis rests upon and presupposes a previously exercised synthesis. Synthesis or totality as such can never be given. Only in so far as a whole is synthetically constructed can it be apprehended by the mind. Representation of the parts precedes and renders possible representation of the whole.

The solution of the dilemma arising out of these diverse views demands the drawing of two distinctions. First, between a synthesised totality and a principle of synthesis; the former may involve a prior synthesis; the latter does not depend upon synthesis, but expresses the predetermined nature of some special form of synthesis. Secondly, it demands a distinction between the a priori manifolds of space and time and the empirical manifold which is apprehended in and through them. This, as we have already noted, is a distinction difficult to take quite seriously, and is entirely unsupported by psychological evidence. But it would seem to be insisted upon by Kant, and to have been a determining factor in the formulation of several of his main doctrines.

In terms of the first distinction we are compelled to recognise that the view of space which underlies the Aesthetic is out of harmony with the teaching of the Analytic. In the Aesthetic Kant interprets space not merely as a form of intuition but also as a formal intuition, which is given complete{96} in its totality, and which is capable of being apprehended independently of its empirical contents, and even prior to them. That would seem to be the view of space which is presupposed in Kant’s explanation of pure mathematical science. The passages from the Analytic, quoted above, are, however, its express recantation. Space, as the intuition of a manifold, is a totum syntheticum, not a totum analyticum. It is constructed, not given. The divergence of views between the Aesthetic and the Analytic springs out of the difficulty of meeting at once the logical demands of a world which Kant conceives objectively, and the psychological demands which arise when this same world is conceived as subjectively conditioned. In principle, the whole precedes the parts; in the process of being brought into existence as an intuition, the parts precede the whole. The principle which determines our apprehension of any space, however small or however large, is that it exists in and through universal space. This is the principle which underlies both the synthetic construction of space and also its apprehension once it is constructed. In principle, therefore, i.e. in the order of logical thought, the whole precedes the parts.[413] The process, however, which this principle governs and directs, cannot start with space as a whole, but must advance to it through synthesis of smaller parts.

But Kant does not himself recognise any conflict between this teaching and the doctrine of the Aesthetic. He seems to himself merely to be making more definite a position which he has consistently held all along; and this was possible owing to his retention and more efficient formulation of the second of the two distinctions mentioned above, viz. that between the manifold of sense and the manifold of intuition. This distinction enables him to graft the new view upon the old, and so in the very act of insisting upon the indispensableness of the conceptual syntheses of understanding, none the less to maintain his view of geometry as an intuitive science.[414]

“Space and time contain a manifold of pure a priori intuition, but at the same time are conditions of the receptivity of our mind—conditions under which alone it can receive representations of{97} objects, and which therefore must also affect the concept of them. But if this manifold is to be known, the spontaneity of our thinking requires that it be gone through in a certain way, taken up, and connected. This action I name synthesis.... Such a synthesis is pure, if the manifold is not empirical, but is given a priori, as is that of space and of time.”[415]

Thus Kant recognises that space, as apprehended by us, is constructed, not given, and so by implication that the infinitude of space is a principle of apprehension, not a given intuition. But he also holds to the view that it contains a pure, and presumably infinite, manifold, given as such.[416] In what this pure manifold consists, and how the description of it as a manifold, demanding synthesis for its apprehension, is to be reconciled with its continuity, Kant nowhere even attempts to explain. Nor does he show what the simple elements are from which the synthesis of apprehension and reproduction in pure intuition might start. The unity and multiplicity of space are, indeed, as he himself recognises,[417] inseparably involved in one another; and recognition of this fact must render it extremely difficult to assign them to separate faculties. For the same reason it is impossible to distinguish temporally, as Kant so frequently does, the processes of synthesis and of analysis, making the former in all cases precede the latter in time. The very nature of space and time, and, as he came to recognise, the very nature of all Ideas of reason, in so far as they involve the notion of the unconditioned, conflict with such a view.

Even when Kant is dealing with space as a principle of synthesis, he speaks with no very certain voice. In the Analytic it is ascribed to the co-operation of sensibility and understanding. In the Dialectic it is, by implication, ascribed to Reason; and in the Metaphysical First Principles it is explicitly so ascribed.

“Absolute space cannot be object of experience; for space without matter is no object of perception, and yet it is a necessary conception of Reason, and therefore nothing but a mere Idea.”[418] “Absolute space is not necessary as a conception of an actual object, but as an Idea which can serve as rule....”[419]

Kant’s teaching in the Critique of Judgment is a further development of this position.

“The mind listens to the voice of Reason which, for every given{98} magnitude—even for those that can never be entirely apprehended, although (in sensible representation) they are judged as entirely given—requires totality.... It does not even except the infinite (space and past time) from this requirement; on the contrary, it renders it unavoidable to think the infinite (in the judgment of common reason) as entirely given (in its totality). But the infinite is absolutely (not merely comparatively) great. Compared with it everything else (of the same kind of magnitudes) is small. But what is most important is that the mere ability to think it as a whole indicates a faculty of mind which surpasses every standard of sense.... The bare capability of thinking the given infinite without contradiction requires in the human mind a faculty itself supersensible. For it is only by means of this faculty and its Idea of a noumenon ... that the infinite of the world of sense, in the pure intellectual estimation of magnitude, can be completely comprehended under one concept.... Nature is, therefore, sublime in those of its phenomena, whose intuition brings with it the Idea of its infinity.... For just as imagination and understanding, in judging of the beautiful, generate a subjective purposiveness of the mental powers by means of their harmony, so imagination and Reason do so by means of their conflict.”[420]

Kant has here departed very far indeed from the position of the Aesthetic.[421]






Space: First Argument.—“Space is not an empirical concept (Begriff) which has been abstracted from outer experiences. For in order that certain sensations be related to something outside me (i.e. to something in another region of space from that in which I find myself), and similarly in order that I may be able to represent them as outside [and alongside][423] one another, and accordingly as not only [qualitatively] different but as in different places, the representation of space must be presupposed (muss schon zum Grunde liegen). The representation of space cannot, therefore, be empirically obtained at second-hand from the relations of outer appearance. This outer experience is itself possible at all only through that representation.”[424]

The first sentence states the thesis of the argument: space is not an empirical concept abstracted from outer experiences. The use of the term Begriff in the title of the section, and also in this sentence, is an instance of the looseness with which Kant employs his terms. It is here synonymous with the term representation (Vorstellung), which covers intuitions as well as general or discursive concepts. Consequently, the contradiction is only verbal, not real, when Kant proceeds to prove that the concept of space is an intuition, not a concept. But this double employment of the term is none the less misleading. When Kant employs it in a strict sense, it signifies solely the general class concept.[425] All true concepts are for Kant of that single type. He has not re-defined the term concept in any{100} manner which would render it applicable to the relational categories. For unfortunately, and very strangely, he never seems to have raised the question whether categories are not also concepts. The application to the forms of understanding of the separate title categories seems to have contented him. Much that is obscure and even contradictory in his teaching might have been prevented had he recognised that the term concept is a generic title which includes, as its sub-species, both general notions and relational categories.

Kant’s limitation of the term concept to the merely generic,[426] and his consequent equating of the categorical proposition with the assertion of the substance-attribute relation,[427] would seem in large part to be traceable to his desire to preserve for himself, in the pioneer labours of his Critical enquiries, the guiding clues of the distinctions drawn in the traditional logic. Kant insists on holding to them, at least in outward appearance, at whatever sacrifice of strict consistency. Critical doctrine is made to conform to the exigencies of an artificial framework, with which its own tenets are only in very imperfect harmony. Appreciation of the ramifying influence, and, as regards the detail of exposition, of the far-reaching consequences, of this desire to conform to the time-honoured rubrics, is indeed an indispensable preliminary to any adequate estimate whether of the strength or of the defects of the Critical doctrines. As a separate and ever-present influence in the determining of Kant’s teaching, this factor may conveniently and compendiously be entitled Kant’s logical architectonic.[428] We shall have frequent occasion to observe its effects.[429]

The second sentence gives expression to the fact through which Kant proves his thesis. Certain sensations, those of the special senses as distinguished from the organic sensations,[430] are related to something which stands in a different region of space from the embodied self, and consequently are apprehended as differing from one another not only in quality but also in spatial position. As is proved later in the Analytic, thought plays an indispensable part in constituting this reference of sensations to objects. Kant here, however, makes no mention of this further complication. He postulates, as he may legitimately do at this stage, the fact that our sensations are{101} thus objectively interpreted, and limits his enquiry to the spatial factor. Now the argument, as Vaihinger justly points out,[431] hinges upon the assumption which Kant has already embodied[432] in his definition of the “form” of sense, viz. that sensations are non-spatial, purely qualitative. Though this is an assumption of which Kant nowhere attempts to give proof, it serves none the less as an unquestioned premiss from which he draws all-important conclusions. This first argument on space derives its force entirely from it.

The proof that the representation of space is non-empirical may therefore be explicitly stated as follows. As sensations are non-spatial and differ only qualitatively, the representation of space must have been added to them. And not being supplied by the given sensations, it must, as the only alternative, have been contributed by the mind. The representation of space, so far from being derived from external experience, is what first renders it possible. As a subjective form that lies ready in the mind, it precedes experience and co-operates in generating it. This proof of the apriority of space is thus proof of the priority of the representation of space to every empirical perception.

In thus interpreting Kant’s argument as proving more than the thesis of the first sentence claims, we are certainly reading into the proof more than Kant has himself given full expression to. But, as is clearly shown by the argument of the next section, we are only stating what Kant actually takes the argument as having proved, namely, that the representation of space is not only non-empirical but is likewise of subjective origin and precedes experience in temporal fashion.

The point of view which underlies and inspires the argument can be defined even more precisely. Kant’s conclusion may be interpreted in either of two ways. The form of space may precede experience only as a potentiality. Existing as a power of co-ordination,[433] it will come to consciousness only indirectly through the addition which it makes to the given sensations. Though subjective in origin, it will be revealed to the mind only in and through experience. This view may indeed be reconciled with the terms of the proof. But a strictly literal interpretation of its actual wording is more in keeping with what, as we shall find, is{102} the general trend of the Aesthetic as a whole. We are then confronted by a very different and extremely paradoxical view, which may well seem too naive to be accepted by the modern reader, but which we seem forced,[434] none the less, to regard as the view actually presented in the text before us. Kant here asserts, in the most explicit manner, that the mind, in order to construe sensations in spatial terms, must already be in possession of a representation of space, and that it is in the light of this representation that it apprehends sensations. The conscious representation of space precedes in time external experience. Such, then, would seem to be Kant’s first argument on space. It seeks to establish a negative conclusion, viz. that space is not derived from experience. But, in so doing, it also yields a positive psychological explanation of its origin.

Those commentators[435] who refuse to recognise that Kant’s problem is in any degree psychological, or that Kant himself so regards it, and who consequently seek to interpret the Aesthetic from the point of view of certain portions of the Analytic, give a very different statement of this first argument. They state it in purely logical terms.[436] Its problem, they claim, is not that of determining the origin of our representation of space, but only its logical relation to our specific sense-experiences. The notion of space in general precedes, as an indispensable logical presupposition, all particular specification of the space relation. Consciousness of space as a whole is not constructed from consciousness of partial spaces; on the contrary, the latter is only possible in and through the former.

Such an argument does of course represent a valuable truth; and it alone harmonises with much in Kant’s maturer teaching;[437] but we must not therefore conclude that it is also the teaching of the Aesthetic. The Critique contains too great a variety of tendencies, too rich a complexity of issues, to allow of such simplification. It loses more than it gains by such rigorous pruning of the luxuriant secondary tendencies of its exposition and thought. And above all, this procedure involves the adoption by the commentator of impossible responsibilities, those of deciding what is essential and valuable in Kant’s thought and what is irrelevant. The value{103} and suggestiveness of Kant’s philosophy largely consist in his sincere appreciation of conflicting tendencies, and in his persistent attempt to reduce them to unity with the least possible sacrifice. But in any case the logical interpretation misrepresents this particular argument. Kant is not here distinguishing between space in general and its specific modifications. He is maintaining that no space relation can be revealed in sensation. It is not only that the apprehension of any limited space presupposes the representation of space as a whole. Both partial and infinite space are of mental origin; sensation, as such, is non-spatial, purely subjective. And lastly, the fact that Kant means to assert that space is not only logically presupposed but is subjectively generated, is sufficiently borne out by his frequent employment elsewhere in the Aesthetic of such phrases as “the subjective condition of sensibility,” “lying ready in our minds,” and “necessarily preceding [as the form of the subject’s receptivity] all intuitions of objects.”

Second Argument.—Having proved by the first argument that the representation of space is not of empirical origin, Kant in the second argument proceeds to establish the positive conclusion that it is a priori.[438] The proof, when all its assumptions are rendered explicit, runs as follows. Thesis: Space is a necessary representation, and consequently is a priori. Proof: It is impossible to imagine the absence of space, though it is possible to imagine it as existing without objects to fill it. A representation which it is impossible for the mind to be without is a necessary representation. But necessity is one of the two criteria of the a priori. The proof of the necessary character of space is therefore also a proof of its being a priori.

The argument, more freely stated, is that what is empirically given from without can be thought away, and that since space cannot be thus eliminated, it must be grounded in our subjective organisation, i.e. must be psychologically a priori. The argument, as stated by Kant, emphasises the apriority, not the subjectivity, of space, but none the less the asserted apriority is psychological, not logical in character. For the criterion employed is not the impossibility of thinking otherwise, but our incapacity to represent this specific element as absent. The ground upon which the whole argument is made to rest is the merely brute fact (asserted by Kant) of our incapacity to think except in terms of space.

The argument is, however, complicated by the drawing of a further consequence, which follows as a corollary from{104} the main conclusion. From the subjective necessity of space follows its objective necessity. Space being necessary a priori, objects can only be apprehended in and through it. Consequently it is not dependent upon the objects apprehended, but itself underlies outer appearances as the condition of their possibility. This corollary is closely akin to the first argument on space, and differs from it only in orientation. The first argument has a psychological purpose. It maintains that the representation of space precedes external experience, causally conditioning it. The corollary has a more objective aim. It concludes that space is a necessary constituent of the external experience thus generated. The one proves that space is a necessary subjective antecedent; the other that it is a necessary objective ingredient.[439]

To consider the proof in detail. The exact words which Kant employs in stating the nervus probandi of the argument are that we can never represent (eine Vorstellung davon machen) space as non-existent, though we can very well think (denken) it as being empty of objects. The terms Vorstellung and denken are vague and misleading. Kant himself recognises that it is possible to conceive that there are beings who intuit objects in some other manner than in space. He cannot therefore mean that we are unable to think or conceive space as non-existent. He must mean that we cannot in imagination intuit it as absent. It is the necessary form of all our intuitions, and therefore also of imagination, which is intuitive in character. Our consciousness is dependent upon given intuitions for its whole content, and to that extent space is a form with which the mind can never by any possibility dispense. Pure thought enables it to realise this de facto limitation, but not to break free from it. Even in admitting the possibility of other beings who are not thus constituted, the mind still recognises its own ineluctable limitations.

Kant offers no proof of his assertion that space can be intuited in image as empty of all sensible content; and as a matter of fact the assertion is false. Doubtless the use of the vague term Vorstellung is in great part responsible for Kant’s mistaken position. So long as imagination and thought are not clearly distinguished, the assertion is correspondingly indefinite. Pure space may possibly be conceived, but it can also be conceived as altogether non-existent. If, on the other hand, our imaginative power is alone in question,{105} the asserted fact must be categorically denied. With the elimination of all sensible content space itself ceases to be a possible image. Kant’s proof thus rests upon a misstatement of fact.

In a second respect Kant’s proof is open to criticism. He takes the impossibility of imagining space as absent as proof that it originates from within. The argument is valid only if no other psychological explanation can be given of this necessity, as for instance through indissoluble association or through its being an invariable element in the given sensations. Kant’s ignoring of these possibilities is due to his unquestioning belief that sensations are non-spatial, purely qualitative. That is a presupposition whose truth is necessary to the cogency of the argument.

Third Argument.—This argument, which was omitted in the second edition, will be considered in its connection with the transcendental exposition into which it was then merged.

Fourth (in second edition, Third) Argument.—The next two arguments seek to show that space is not a discursive or general concept but an intuition. The first proof falls into two parts, (a) We can represent only a single space. For though we speak of many spaces, we mean only parts of one and the same single space. Space must therefore be an intuition. For only intuition is thus directly related to a single individual. A concept always refers indirectly, per notas communes, to a plurality of individuals. (b) The parts of space cannot precede the one all-comprehensive space. They can be thought only in and through it. They arise through limitation of it. Now the parts (i.e. the attributes) which compose a concept precede it in thought. Through combination of them the concept is formed. Space cannot, therefore, be a concept. Consequently it must, as the only remaining alternative, be an intuition. Only in an intuition does the whole precede the parts. In a concept the parts always precede the whole. Intuition stands for multiplicity in unity, conception for unity in multiplicity.

The first part of the argument refers to the extension, the second part to the intension of the space representation. In both aspects it appears as intuitional.[440]

Kant, in repeating his thesis as a conclusion from the above grounds, confuses the reader by an addition which is not strictly relevant to the argument, viz. by the statement that this intuition must be non-empirical and a priori. This is simply a recapitulation of what has been established in the preceding proofs. It is not, as might at first sight{106} appear, part of the conclusion established by the argument under consideration. The reader is the more apt to be misled owing to the fact that very obviously arguments for the non-empirical and for the a priori character of space can be derived from proof (b). That space is non-empirical would follow from the fact that representation of space as a whole is necessary for the apprehension of any part of it. Empirical intuition can only yield the apprehension of a limited space. The apprehension of the comprehensive space within which it falls must therefore be non-empirical.

“As we intuitively apprehend (anschauend erkennen) not only the space of the object which affects our senses, but the whole space, space cannot arise out of the actual affection of the senses, but must precede it in time (vor ihr vorhergehen).”[441]

But in spite of its forcibleness this argument is nowhere presented in the Critique.

Similarly, in so far as particular spaces can be conceived only in and through space as a whole, and in so far as the former are limitations of the one antecedent space, the intuition which underlies all external perception must be a priori. This is in essentials a stronger and more cogent mode of formulating the second argument on space. But again, and very strangely, it is nowhere employed by Kant in this form.

The concluding sentence, ambiguously introduced by the words so werden auch, is tacked on to the preceding argument. Interpreted in the light of § 15 C of the Dissertation,[442] and of the corresponding fourth[443] argument[444] on time, it may be taken as offering further proof that space is an intuition. The concepts of line and triangle, however attentively contemplated, will never reveal the proposition that in every triangle two sides taken together are greater than the third. An a priori intuition will alone account for such apodictic knowledge. This concluding sentence thus really belongs to the transcendental exposition; and as such ought, like the third argument, to have been omitted in the second edition.

Kant’s proof rests on the assumption that there are only two kinds of representation, intuitions and concepts, and also in equal degree upon the further assumption that all concepts{107} are of one and the same type.[445] Intuition is, for Kant, the apprehension of an individual. Conception is always the representation of a class or genus. Intuition is immediately related to the individual. Conception is reflective or discursive; it apprehends a plurality of objects indirectly through the representation of those marks which are common to them all.[446] Intuition and conception having been defined in this manner, the proof that space is single or individual, and that in it the whole precedes the parts, is proof conclusive that it is an intuition, not a conception. Owing, however, to the narrowness of the field assigned to conception, the realm occupied by intuition is proportionately wide, and the conclusion is not as definite and as important as might at first sight appear. By itself, it amounts merely to the statement, which no one need challenge, that space is not a generic class concept. Incidentally certain unique characteristics of space are, indeed, forcibly illustrated; but the implied conclusion that space on account of these characteristics must belong to receptivity, not to understanding, does not by any means follow. It has not, for instance, been proved that space and time are radically distinct from the categories, i.e. from the relational forms of understanding.

In 1770, while Kant still held to the metaphysical validity of the pure forms of thought, the many difficulties which result from the ascription of independent reality to space and time were, doubtless, a sufficient reason for regarding the latter as subjective and sensuous. But upon adoption of the Critical standpoint such argument is no longer valid. If all our forms of thought may be subjective, the existence of antinomies has no real bearing upon the question whether space and time do or do not have a different constitution and a different mental origin from the categories. The antinomies, that is to say, may perhaps suffice to prove that space and time are subjective; they certainly do not establish their sensuous character.

But though persistence of the older, un-Critical opposition between the intellectual and the sensuous was partly responsible for Kant’s readiness to regard as radical the very obvious differences between a category such as that of substance and attribute and the visual or tactual extendedness with which objects are endowed, it can hardly be viewed as the really decisive influence. That would rather seem to be traceable to Kant’s conviction that mathematical knowledge is unique both in fruitfulness and in certainty, and to his further belief that it owes this distinction to the content character of{108} the a priori forms upon which it rests. For though the categories of the physical sciences are likewise a priori, they are exclusively relational,[447] and serve only to organise a material that is empirically given. To account for the superiority of mathematical knowledge Kant accordingly felt constrained to regard space and time as not merely forms in terms of which we interpret the matter of sense, but as also themselves intuited objects, and as therefore possessing a character altogether different from anything which can be ascribed to the pure understanding. The opposition between forms of sense and categories of the understanding, in the strict Kantian mode of envisaging that opposition, is thus inseparably bound up with Kant’s doctrine of space and time as being not only forms of intuition, but as also in their purity and independence themselves intuitions. Even the sensuous subject matter of pure mathematics—so Kant would seem to contend—is a priori in nature. If this latter view be questioned—and to the modern reader it is indeed a stone of stumbling—much of the teaching of the Aesthetic will have to be modified or at least restated.

Fifth (in second edition, Fourth) Argument.—This argument is quite differently stated in the two editions of the Critique, though the purpose of the argument is again in both cases to prove that space is an intuition, not a general concept. In the first edition this is proved by reference to the fact that space is given as an infinite magnitude. This characteristic of our space representation cannot be accounted for so long as it is regarded as a concept. A general conception of space which would abstract out those properties and relations which are common to all spaces, to a foot as well as to an ell, could not possibly determine anything in regard to magnitude. For since spaces differ in magnitude, any one magnitude cannot be a common quality. Space is, however, given us as determined in magnitude, namely, as being of infinite magnitude; and if a general conception of space relations cannot determine magnitude, still less can it determine infinite magnitude. Such infinity must be derived from limitlessness in the progression of intuition. Our conceptual representations of infinite magnitude must be derivative products, acquired from this intuitive source.

In the argument of the second edition the thesis is again established by reference to the infinity of space. But in all other respects the argument differs from that of the first {109}edition. A general conception, which abstracts out common qualities from a plurality of particulars, contains an infinite number of possible different representations under it; but it cannot be thought as containing an infinite number of representations in it. Space must, however, be thought in this latter manner, for it contains an infinite number of coexisting parts.[448] Since, then, space cannot be a concept, it must be an intuition.

The definiteness of this conclusion is somewhat obscured by the further characterisation of the intuition of space as a priori, and by the statement that it is the original (ursprüngliche) representation which is of this intuitive nature. The first addition must here, again, just as in the fourth argument, be regarded as merely a recapitulation of what has already been established, not a conclusion from the present argument. The introduction of the word ‘original’ seems to be part of Kant’s reply to the objections which had already been made to his admission in the first edition that there is a conception as well as an intuition of space. It is the original given intuition of space which renders such reflective conception possible.

The chief difficulty of these proofs arises out of the assertion which they seem to involve that space is given as actually infinite. There are apparently, on this point, two views in Kant, which were retained up to the very last, and which are closely connected with his two representations of space, on the one hand as a formal intuition given in its purity and in its completeness, and on the other hand as the form of intuition, which exists only so far as it is constructed, and which is dependent for its content upon given matter.

Third Argument, and Transcendental Exposition of Space.—The distinction between the metaphysical and the transcendental expositions, introduced in the second edition of the Critique,[449] is one which Kant seems to have first made clear to himself in the process of writing the Prolegomena.[450] It is a genuine improvement, marking an important distinction. It separates out two comparatively independent lines of argument. The terms in which the distinction is stated are not, however, felicitous. Kant’s reason for adopting the title metaphysical is indicated in the Prolegomena:[451]

“As concerns the sources of metaphysical cognition, its very concept implies that they cannot be empirical.... For it must not{110} be physical but metaphysical knowledge, i.e. knowledge lying beyond experience.... It is therefore a priori knowledge, coming from pure understanding and pure Reason.”

The metaphysical exposition, it would therefore seem, is so entitled because it professes to prove that space is a priori, not empirical, and to do so by analysis of its concept.[452] Now by Kant’s own definition of the term transcendental, as the theory of the a priori, this exposition might equally well have been named the transcendental exposition. In any case it is an essential and chief part of the Transcendental Aesthetic. Such division of the Transcendental Aesthetic into a metaphysical and a transcendental part involves a twofold use, wider and narrower, of one and the same term. Only as descriptive of the whole Aesthetic is transcendental employed in the sense defined.

Exposition (Erörterung, Lat. expositio) is Kant’s substitute for the more ordinary term definition. Definition is the term which we should naturally have expected; but as Kant holds that no given concept, whether a priori or empirical, can be defined in the strict sense,[453] the substitutes the term exposition, using it to signify such definition of the nature of space as is possible to us. To complete the parallelism Kant speaks of the transcendental enquiry as also an exposition. It is, however, in no sense a definition. Kant’s terms here, as so often elsewhere, are employed in a more or less arbitrary and extremely inexact manner.

The distinction between the two expositions is taken by Kant as follows. The metaphysical exposition determines the nature of the concept of space, and shows it to be a given a priori intuition. The transcendental exposition shows how space, when viewed in this manner, renders comprehensible the possibility of synthetic a priori knowledge.

The omission of the third argument on space from the second edition, and its incorporation into the new transcendental exposition, is certainly an improvement. In its location in the first edition, it breaks in upon the continuity of Kant’s argument without in any way contributing to the further {111}definition of the concept of space. Also, in emphasising that mathematical knowledge depends upon the construction of concepts,[454] Kant presupposes that space is intuitional; and that has not yet been established.

The argument follows the strict, rigorous, synthetic method. From the already demonstrated a priori character of space, Kant deduces the apodictic certainty of all geometrical principles. But though the paragraph thus expounds a consequence that follows from the a priori character of space, not an argument in support of it, something in the nature of an argument is none the less implied. The fact that this view of the representation of space alone renders mathematical science possible can be taken as confirming this interpretation of its nature. Such an argument, though circular, is none the less cogent. Consideration of Kant’s further statements, that were space known in a merely empirical manner we could not be sure that in all cases only one straight line is possible between two points, or that space will always be found to have three dimensions, must meantime be deferred.[455]

In the new transcendental exposition Kant adopts the analytic method of the Prolegomena, and accordingly presents his argument in independence of the results already established. He starts from the assumption of the admitted validity of geometry, as being a body of synthetic a priori knowledge. Yet this, as we have already noted, does not invalidate the argument; in both the first and the last paragraphs it is implied that the a priori and intuitive characteristics of space have already been proved. From the synthetic character of geometrical propositions Kant argues[456] that space must be an intuition. Through pure concepts no synthetic knowledge is possible. Then from the apodictic character of geometry he infers that space exists in us as pure and a priori;[457] no experience can ever reveal necessity. But geometry also exists as an applied science; and to account for our power of anticipating experience, we must view space as existing only in the perceiving subject as the form of its sensibility. If it precedes objects as the necessary subjective condition of their apprehension, we can to that extent predetermine the conditions of their existence.

In the concluding paragraph Kant says that this is the only explanation which can be given of the possibility of geometry. He does not distinguish between pure and applied{112} geometry, though the proof which he has given of each differs in a fundamental respect. Pure geometry presupposes only that space is an a priori intuition; applied geometry demands that space be conceived as the a priori form of external sense. Only in reference to applied geometry does the Critical problem arise:—viz. how we can form synthetic judgments a priori which yet are valid of objects; or, in other words, how judgments based upon a subjective form can be objectively valid. But any attempt, at this point, to define the nature and possibility of applied geometry must anticipate a result which is first established in Conclusion b.[458] Though, therefore, the substitution of this transcendental exposition for the third space argument is a decided improvement, Kant, in extending it so as to cover applied as well as pure mathematics, overlooks the real sequence of his argument in the first edition. The employment of the analytic method, breaking in, as it does, upon the synthetic development of Kant’s original argument, is a further irregularity.[459]

It may be noted that in the third paragraph Kant takes the fact that geometry can be applied to objects as proof of the subjectivity of space.[460] He refuses to recognise the possibility that space may be subjective as a form of receptivity, and yet also be a mode in which things in themselves exist. This, as regards its conclusion, though not as regards its argument, is therefore an anticipation of Conclusion a. In the last paragraph Kant is probably referring to the views both of Leibniz and of Berkeley.


Conclusion a.Thesis: Space is not a property of things in themselves,[462] nor a relation of them to one another. Proof: The properties of things in themselves can never be intuited prior to their existence, i.e. a priori. Space, as already proved, is intuited in this manner. In other words, the apriority of space is by itself sufficient proof of its subjectivity.{113}

This argument has been the subject of a prolonged controversy between Trendelenburg and Kuno Fischer.[463] Trendelenburg was able to prove his main point, namely, that the above argument is quite inconclusive. Kant recognises only two alternatives, either space as objective is known a posteriori, or being an a priori representation it is subjective in origin. There exists a third alternative, namely, that though our intuition of space is subjective in origin, space is itself an inherent property of things in themselves. The central thesis of the rationalist philosophy of the Enlightenment was, indeed, that the independently real can be known by a priori thinking. Even granting the validity of Kant’s later conclusion, first drawn in the next paragraph, that space is the subjective form of all external intuition, that would only prove that it does not belong to appearances, prior to our apprehension of them; nothing is thereby proved in regard to the character of things in themselves. We anticipate by a priori reasoning only the nature of appearances, never the constitution of things in themselves. Therefore space, even though a priori, may belong to the independently real. The above argument cannot prove the given thesis.

Vaihinger contends[464] that the reason why Kant does not even attempt to argue in support of the principle, that the a priori must be purely subjective, is that he accepts it as self-evident. This explanation does not, however, seem satisfactory. But Vaihinger supplies the data for modification of his own assertion. It was, it would seem, the existence of the antinomies which first and chiefly led Kant to assert the subjectivity of space and time.[465] For as he then believed that a satisfactory solution of the antinomies is possible only on the assumption of the subjectivity of space and time, he regarded their subjectivity as being conclusively established, and accordingly failed to examine with sufficient care the validity of his additional proof from their apriority. This would seem to be confirmed by the fact that when later,[466] in reply to criticisms of the arguments of the first edition, he so far modified his position as to offer reasons in support of the above general principle, even then he nowhere discussed the principle in reference to the forms of sense. All his discussions concern only the possible independent reality of the forms of thought.[467] To the very last Kant would seem to have regarded the above argument{114} as an independent, and by itself a sufficient, proof of the subjectivity of space.

The refutation of Trendelenburg’s argument which is offered by Caird[468] is inconclusive. Caird assumes the chief point at issue, first by ignoring the possibility that space may be known a priori in reference to appearances and yet at the same time be transcendently real; and secondly by ignoring the fact that to deny spatial properties to things in themselves is as great a violation of Critical principles as to assert them. One point, however, in Caird’s reply to Trendelenburg calls for special consideration, viz. Caird’s contention that Kant did actually take account of the third alternative, rejecting it as involving the “absurd” hypothesis of a pre-established harmony.[469] Undoubtedly Kant did so. But the contention has no relevancy to the point before us. The doctrine of pre-established harmony is a metaphysical theory which presupposes the possibility of gaining knowledge of things in themselves. For that reason alone Kant was bound to reject it. A metaphysical proof of the validity of metaphysical judgments is, from the Critical point of view, a contradiction in terms. As the validity of all speculations is in doubt, a proof which is speculative cannot meet our difficulties. And also, as Kant himself further points out, the pre-established harmony, even if granted, can afford no solution of the Critical problem how a priori judgments can be passed upon the independently real. The judgments, thus guaranteed, could only possess de facto validity; we could never be assured of their necessity.[470] It is chiefly in these two inabilities that Kant locates the “absurdity” of a theory of pre-established harmony. The refutation of that theory does not, therefore, amount to a disproof of the possibility which we are here considering.

Conclusion b.—The next paragraph maintains two theses: (a) that space is the form of all outer intuition; (b) that this fact explains what is otherwise entirely inexplicable and paradoxical, namely, that we can make a priori judgments which yet apply to the objects experienced. The first thesis, that the pure intuition of space is only conceivable as the form of appearances of outer sense, is propounded in the opening sentence without argument and even without citation of {115}grounds. The statement thus suddenly made is not anticipated save by the opening sentences of the section on space.[471] It is an essentially new doctrine. Hitherto Kant has spoken of space only as an a priori intuition. The further assertion that as such it must necessarily be conceived as the form of outer sense (i.e. not only as a formal intuition but also as a form of intuition), calls for the most definite and explicit proof. None, however, is given. It is really a conclusion from points all too briefly cited by Kant in the general Introduction, namely, from his distinction between the matter and the form of sense. The assertions there made, in a somewhat casual manner, are here, without notification to the reader, employed as premisses to ground the above assertion. His thesis is not, therefore, as by its face value it would seem to profess to be, an inference from the points established in the preceding expositions. It interprets these conclusions in the light of points considered in the Introduction; and thereby arrives at a new and all-important interpretation of the nature of the a priori intuition of space.

The second thesis employs the first to explain how prior to all experience we can determine the relations of objects. Since (a) space is merely the form of outer sense, and (b) accordingly exists in the mind prior to all empirical intuition, all appearances must exist in space, and we can predetermine them from the pure intuition of space that is given to us a priori. Space, when thus viewed as the a priori form of outer sense, renders comprehensible the validity of applied mathematics.

As we have already noted,[472] Kant in the second edition obscures the sequence of his argument by offering in the new transcendental exposition a justification of applied as well as of pure geometry. In so doing he anticipates the conclusion which is first drawn in this later paragraph. This would have been avoided had Kant given two separate transcendental expositions. First, an exposition of pure mathematics, placed immediately after the metaphysical exposition; for pure mathematics is exclusively based upon the results of the metaphysical exposition. And secondly, an exposition of applied mathematics, introduced after Conclusion b. The explanation of applied geometry is really the more essential and central of the two, as it alone involves the truly Critical problem, how judgments formed a priori can yet apply to objects. Conclusion b constitutes, as Vaihinger rightly insists,[473] the very heart of the Aesthetic. The arrangement of Kant’s argument diverts the reader’s attention from where it ought properly to centre.{116}

The use which Kant makes of the Prolegomena in his statement of the new transcendental exposition is one cause of the confusion. The exposition is a brief summary of the corresponding Prolegomena[474] sections. In introducing this summary into the Critique Kant overlooked the fact that in referring to applied mathematics he is anticipating a point first established in Conclusion b. The real cause, however, of the trouble is common to both editions, namely Kant’s failure clearly to appreciate the fundamental distinction between the view that space is an a priori intuition and the view that it is the a priori form of all external intuition, i.e. of outer sense. He does not seem to have fully realised how very different are those two views. In consequence of this he fails to distinguish between the transcendental expositions of pure and applied geometry.[475]

Third paragraph.—Kant proceeds to develop the subjectivist conclusions which follow from a and b.

“We may say that space contains all things which can appear to us externally, but not all things in themselves, whether intuited or not, nor again all things intuited by any and every subject.”[476]

This sentence makes two assertions: (a) space does not belong to things in and by themselves; (b) space is not a necessary form of intuition for all subjects whatsoever.

The grounds for the former assertion are not here considered, and that is doubtless the reason why the oder nicht is excised in Kant’s private copy of the Critique. As we have seen, Kant does not anywhere in the Aesthetic even attempt to offer argument in support of this assertion. In defence of (a) Kant propounds for the first time the view of sensibility as a limitation. Space is a limiting condition to which human intuition is subject. Whether the intuitions of other thinking beings are subject to the same limitation, we have no means of deciding. But for all human beings, Kant implies, the same conditions must hold universally.[477]

In the phrase “transcendental ideality of space”[478] Kant, it may be noted, takes the term ideality as signifying subjectivity, and the term transcendental as equivalent to transcendent. He is stating that judged from a transcendent point of view, i.e. from the point of view of the thing in itself, space has a merely subjective or “empirical” reality. This is an{117} instance of Kant’s careless use of the term transcendental. Space is empirically real, but taken transcendently, is merely ideal.[479]


This is an appropriate point at which to consider the consistency of Kant’s teaching with modern developments in geometry. Kant’s attitude has very frequently been misrepresented. As he here states, he is willing to recognise that the forms of intuition possessed by other races of finite beings may not coincide with those of the human species. But in so doing he does not mean to assert the possibility of other spatial forms, i.e. of spaces that are non-Euclidean. In his pre-Critical period Kant had indeed attempted to deduce the three-dimensional character of space as a consequence of the law of gravitation; and recognising that that law is in itself arbitrary, he concluded that God might, by establishing different relations of gravitation, have given rise to spaces of different properties and dimensions.

“A science of all these possible kinds of space would undoubtedly be the highest enterprise which a finite understanding could undertake in the field of geometry.”[480]

But from the time of Kant’s adoption, in 1770, of the Critical view of space as being the universal form of our outer sense, he seems to have definitely rejected all such possibilities. Space, to be space at all, must be Euclidean; the uniformity of space is a presupposition of the a priori certainty of geometrical science.[481] One of the criticisms which in the Dissertation[482] he passes upon the empirical view of mathematical{118} science is that it would leave open the possibility that “a space may some time be discovered endowed with other fundamental properties, or even perhaps that we may happen upon a two-sided rectilinear figure.” This is the argument which reappears in the third argument on space in the first edition of the Critique.[483] The same examples are employed with a somewhat different wording.

“It would not even be necessary that there should be only one straight line between two points, though experience invariably shows this to be so. What is derived from experience has only comparative universality, namely, that which is obtained through induction. We should therefore only be able to say that, so far as hitherto observed, no space has been found which has more than three dimensions.”

But that Kant should have failed to recognise the possibility of other spaces does not by itself point to any serious defect in his position. There is no essential difficulty in reconciling the recognition of such spaces with his fundamental teaching. He admits that other races of finite beings may perhaps intuit through non-spatial forms of sensibility; he might quite well have recognised that those other forms of intuition, though not Euclidean, are still spatial. It is in another and more vital respect that Kant’s teaching lies open to criticism. Kant is convinced that space is given to us in intuition as being definitely and irrevocably Euclidean in character. Both our intuition and our thinking, when we reflect upon space, are, he implies, bound down to, and limited by, the conditions of Euclidean space. And it is in this positive assumption, and not merely in his ignoring of the possibility of other spaces, that he comes into conflict with the teaching of modern geometry. For in making the above assumption Kant is asserting that we definitely know physical space to be three-dimensional, and that by no elaboration of concepts can we so remodel it in thought that the axiom of parallels will cease to hold. Euclidean space, Kant implies, is given to us as an unyielding form that rigidly resists all attempts at conceptual reconstruction. Being quite independent of thought and being given as complete, it has no inchoate plasticity of which thought might take advantage. The modern geometer is not, however, prepared to admit that intuitional space has any definiteness or preciseness of nature apart from the concepts through which it is apprehended; and he therefore allows, as at least possible, that upon clarification of our concepts space may be discovered to be radically different from what it at first sight appears to be. In any{119} case, the perfecting of the concepts must have some effect upon their object. But even—as the modern geometer further maintains—should our space be definitely proved, upon analytic and empirical investigation, to be Euclidean in character, other possibilities will still remain open for speculative thought. For though the nature of our intuitional data may constrain us to interpret them through one set of concepts rather than through another, the competing sets of alternative concepts will represent genuine possibilities beyond what the actual is found to embody.

Thus the defect of Kant’s teaching, in regard to space, as judged in the light of the later teaching of geometrical science, is closely bound up with his untenable isolation of the a priori of sensibility from the a priori of understanding.[484] Space, being thus viewed as independent of thought, has to be regarded as limiting and restricting thought by the unalterable nature of its initial presentation. And unfortunately this is a position which Kant continued to hold, despite his increasing recognition of the part which concepts must play in the various mathematical sciences. In the deduction of the first edition we find him stating that synthesis of apprehension is necessary to all representation of space and time.[485] He further recognises that all arithmetical processes are syntheses according to concepts.[486] And in the Prolegomena[487] there occurs the following significant passage.

“Do these laws of nature lie in space, and does the understanding learn them by merely endeavouring to find out the fruitful meaning that lies in space; or do they inhere in the understanding and in the way in which it determines space according to the conditions of the synthetical unity towards which its concepts are all directed? Space is something so uniform and as to all particular properties so indeterminate, that we should certainly not seek a store of laws of nature in it. That which determines space to the form of a circle or to the figures of a cone or a sphere, is, on the contrary, the understanding, so far as it contains the ground of the unity of these constructions. The mere universal form of intuition, called space, must therefore be the substratum of all intuitions determinable to particular objects, and in it, of course, the condition of the possibility and of the variety of these intuitions lies. But the unity of the objects is solely determined by the understanding, and indeed in accordance with conditions which are proper to the nature of the understanding....”

Obviously Kant is being driven by the spontaneous development of his own thinking towards a position much more{120} consistent with present-day teaching, and completely at variance with the hard and fast severance between sensibility and understanding which he had formulated in the Dissertation and has retained in the Aesthetic. In the above Prolegomena passage a plasticity is being allowed to space, sufficient to permit of essential modification in the conceptual processes through which it is articulated. But, as I have just stated, that did not lead Kant to disavow the conclusions which he had drawn from his previous teaching.

This defect in Kant’s doctrine of space, as expounded in the Aesthetic, indicates a further imperfection in his argument. He asserts that the form of space cannot vary from one human being to another, and that for this reason the judgments which express it are universally valid. Now, in so far as Kant’s initial datum is consciousness of time,[488] he is entirely justified in assuming that everything which can be shown to be a necessary condition of such consciousness must be uniform for all human minds. But as his argument is not that consciousness of Euclidean space is necessary to consciousness of time, but only that consciousness of the permanent in space is a required condition, he has not succeeded in showing the necessary uniformity of the human mind as regards the specific mode in which it intuits space. The permanent might still be apprehended as permanent, and therefore as yielding a possible basis for consciousness of sequence, even if it were apprehended in some four-dimensional form.


Fourth Paragraph.—The next paragraph raises one of the central problems of the Critique, namely, the question as to the kind of reality possessed by appearances. Are they subjective, like taste or colour? Or have they a reality at least relatively independent of the individual percipient? In other words, is Kant’s position subjectivism or phenomenalism? Kant here alternates between these positions. This fourth paragraph is coloured by his phenomenalism, whereas in the immediately following fifth paragraph his subjectivism gains the upper hand. The taste of wine, he there states, is purely subjective, because dependent upon the particular constitution of the gustatory organ on which the wine acts. Similarly, colours are not properties of the objects which cause them.

“They are only modifications of the sense of sight which is affected in a certain manner by the light.... They are connected{121} with the appearances only as effects accidentally added by the particular constitution of the sense organs.”[489]

Space, on the other hand, is a necessary constituent of the outer objects. In contrast to the subjective sensations of taste and colour, it possesses objectivity. This mode of distinguishing between space and the matter of sense implies that extended objects are not mere ideas, but are sufficiently independent to be capable of acting upon the sense organs, and of thereby generating the sensations of the secondary qualities.

Kant, it must be observed, refers only to taste and colour. He says nothing in regard to weight, impenetrability, and the like. These are revealed through sensation, and therefore on his view ought to be in exactly the same position as taste or colour. But if so, the relative independence of the extended object can hardly be maintained. Kant’s distinction between space and the sense qualities cannot, indeed, be made to coincide with the Cartesian distinction between primary and secondary qualities.

A second difference, from Kant’s point of view, between space and the sense qualities is that the former can be represented a priori, in complete separation from everything empirical, whereas the latter can only be known a posteriori. This, as we have seen, is a very questionable assertion. The further statement that all determinations of space can be represented in the same a priori fashion is even more questionable. At most the difference is only between a homogeneous subjective form yielded by outer sense and the endlessly varied and consequently unpredictable contents revealed by the special senses. The contention that the former can be known apart from the latter implies the existence of a pure manifold additional to the manifold of sense.

Fifth Paragraph.—In the next paragraph Kant emphasises the distinction between the empirical and the transcendental meanings of the term appearance. A rose, viewed empirically, as a thing with an intrinsic independent nature, may appear of different colour to different observers.

“The transcendental conception of appearances in space, on the other hand, is a Critical reminder that nothing intuited in space is a thing in itself, that space is not a form inhering in things in themselves ... and that what we call outer objects are nothing but mere representations of our sensibility, the form of which is space.”

In other words, the distinction drawn in the preceding paragraph between colour as a subjective effect and space as{122} an objective existence is no longer maintained. Kant, when thus developing his position on subjectivist lines, allows no kind of independent existence to anything in the known world. Objects as known are mere Ideas (blosse Vorstellungen unserer Sinnlichkeit), the sole correlate of which is the unknowable thing in itself. But even in this paragraph both tendencies find expression. “Colour, taste, etc., must not rightly be regarded as properties of things, but only as changes in the subject.” This implies a threefold distinction between subjective sensations, empirical objects in space, and the thing in itself. The material world, investigated by science, is recognised as possessing a relatively independent mode of existence.

Substituted Fourth Paragraph of second edition.—In preparing the second edition Kant himself evidently felt the awkwardness of this abrupt juxtaposition of the two very different points of view; and he accordingly adopts a non-committal attitude, substituting a logical distinction for the ontological. Space yields synthetic judgments a priori; the sense qualities do not. Only in the concluding sentence does there emerge any definite phenomenalist implication. The sense qualities, “as they are mere sensations and not intuitions, in themselves reveal no object, least of all [an object] a priori.”[490] The assertion that the secondary qualities have no ideality implies a new and stricter use of the term ideal than we find anywhere in the first edition—a use which runs counter to Kant’s own constant employment of the term. On this interpretation it is made to signify what though subjective is also a priori. Here, as in many of the alterations of the second edition, Kant is influenced by the desire to emphasise the points which distinguish his idealism from that of Berkeley.{123}





Time: First Argument.—This argument is in all respects the same as the first argument on space. The thesis is that the representation[491] of time is not of empirical origin. The proof is based on the fact that this representation must be previously given in order that the perception of coexistence or succession be possible. It also runs on all fours with the first argument in the Dissertation.

The idea of time does not originate in, but is presupposed by the senses. When a number of things act upon the senses, it is only by means of the idea of time that they can be represented whether as simultaneous or as successive. Nor does succession generate the conception of time; but stimulates us to form it. Thus the notion of time, even if acquired through experience, is very badly defined as being a series of actual things existing one after another. For I can understand what the word after signifies only if I already know what time means. For those things are after one another which exist at different times, as those are simultaneous which exist at one and the same time.”[492]

Second Argument.—Kant again applies to time the argument already employed by him in dealing with space. The thesis is that time is given a priori. Proof is found in the fact that it cannot be thought away, i.e. in the fact of its subjective necessity. From this subjective necessity follows its objective necessity, so far as all appearances are concerned. In the second edition Kant added a phrase—“as the general condition of their possibility”—which is seriously {124}misleading. The concluding sentence is thereby made to read as if Kant were arguing from the objective necessity of time, i.e. from its necessity as a constituent in the appearances apprehended, to its apriority. It is indeed possible that Kant himself regarded this objective necessity of time as contributing to the proof of its apriority. But no such argument can be accepted. Time may be necessary to appearances, once appearances are granted. This does not, however, prove that it must therefore precede them a priori. This alteration in the second edition is an excellent, though unfortunate, example of Kant’s invincible carelessness in the exposition of his thought. It has contributed to a misreading by Herbart and others of this and of the corresponding argument on space.

“Let us not talk of an absolute space as the presupposition of all our constructed figures. Possibility is nothing but thought, and it arises only when it is thought. Space is nothing but possibility, for it contains nothing save images of the existent; and absolute space is nothing save the abstracted general possibility of such constructions, abstracted from it after completion of the construction. The necessity of the representation of space ought never to have played any rôle in philosophy. To think away space is to think away the possibility of that which has been previously posited as actual. Obviously that is impossible, and the opposite is necessary.”[493]

Were Kant really arguing here and in the second argument on space solely from the objective necessity of time and space, this criticism would be unanswerable. But even taking the argument in its first edition form, as an argument from the psychological necessity of time, it lies open to the same objection as the argument on space. It rests upon a false statement of fact. We cannot retain time in the absence of all appearances of outer and inner sense. With the removal of the given manifold, time itself must vanish.

Fourth Argument.[494]—This argument differs only slightly, and mainly through omissions,[495] from the fourth[496] of the arguments in regard to space; but a few minor points call for notice. (a) In the first sentence, instead of intuition, which alone is under consideration in its contrast to conception, Kant employs the phrase “pure form of intuition.” (b) In the third sentence Kant uses the quite untenable phrase “given through a single object (Gegenstand).” Time is not given{125} from without, nor is it due to an object. (c) The concluding sentences properly belong to the transcendental exposition. They are here introduced, not in the ambiguous manner of the fourth[1] argument on space, but explicitly as a further argument in proof of the intuitive character of time. The synthetic proposition which Kant cites is taken neither from the science of motion nor from arithmetic. It expresses the nature of time itself, and for that reason is immediately contained in the intuition of time.

Fifth Argument.—This argument differs fundamentally from the corresponding argument on space, whether of the first or of the second edition, and must therefore be independently analysed. The thesis is again that time is an intuition. Proof is derived from the fact that time is a representation in which the parts arise only through limitation, and in which, therefore, the whole must precede the parts. The original (ursprüngliche) time-representation, i.e. the fundamental representation through limitation of which the parts arise as secondary products, must be an intuition.

To this argument Kant makes two explanatory additions. (a) As particular times arise through limitation of one single time, time must in its original intuition be given as infinite, i.e. as unlimited. The infinitude of time is not, therefore, as might seem to be implied by the prominence given to it, and by analogy with the final arguments of both the first and the second edition, a part of the proof that it is an intuition, but only a consequence of the feature by which its intuitive character is independently established. The unwary reader, having in mind the corresponding argument on space, is almost inevitably misled. All reference to infinitude could, so far as this argument is concerned, have been omitted. The mode in which the argument opens seems indeed to indicate that Kant was not himself altogether clear as to the cross-relations between the arguments on space and time respectively. The real parallel to this argument is to be found in the second part of the fourth[1] argument on space. That part was omitted by Kant in his fourth argument on time, and is here developed into a separate argument. This is, of course, a further cause of confusion to the reader, who is not prepared for such arbitrary rearrangement. Indeed it is not surprising to find that when Kant became the reader of his own work, in preparing it for the second edition, he was himself misled by the intricate perversity of his exposition. In re-reading the argument he seems to have forgotten that it represents the second part of the fourth[497] argument{126} on space. Interpreting it in the light of the fifth[498] argument on space which he had been recasting for the second edition, it seemed to him possible, by a slight alteration, to bring this argument on time into line with that new proof.[499] This unfortunately results in the perverting of the entire paragraph. The argument demands an opposition between intuition in which the whole precedes the parts, and conception in which the parts precede the whole. In order to bring the opposition into line with the new argument on space, according to which a conception contains an infinite number of parts, not in it, but only under it, Kant substitutes for the previous parenthesis the statement that “concepts contain only partial representations,” meaning, apparently, that their constituent elements are merely abstracted attributes, not real concrete parts, or in other words, not strictly parts at all, but only partial representations. But this does not at all agree with the context. The point at issue is thereby obscured.

(b) The main argument rests upon and presupposes a very definite view as to the manner in which alone, according to Kant, concepts are formed. Only if this view be granted as true of all concepts without exception is the argument cogent. This doctrine[500] of the concept is accordingly stated by Kant in the words of the parenthesis. The partial representations, i.e. the different properties which go to constitute the object or content conceived, precede the representation of the whole. “The aggregation of co-ordinate attributes (Merkmale) constitutes the totality of the concept.”[501] Upon the use which Kant thus makes of the traditional doctrine of the concept, and upon its lack of consistency with his recognition of relational categories, we have already dwelt.[502]

Third Argument and the Transcendental Exposition.—The third argument ought to have been omitted in the second edition, and its substance incorporated in the new transcendental exposition, as was done with the corresponding argument concerning space. The excuse which Kant offers for not making the change, namely, his desire for brevity, is not valid. By insertion in the new section the whole matter could have been stated just as briefly as before.

The purpose of the transcendental exposition has been already defined. It is to show how time, when viewed in the manner required by the results of the metaphysical deduction,{127} as an a priori intuition, renders synthetic a priori judgments possible.

This exposition, as it appears in the third argument of the first edition, grounds the apodictic character of two axioms in regard to time[503] on the proved apriority of the representation of time, and then by implication finds in these axioms a fresh proof of the apriority of time.

The new transcendental exposition extends the above by two further statements: (a) that only through the intuition of time can any conception of change, and therewith of motion (as change of place), be formed; and (b) that it is because the intuition of time is an a priori intuition that the synthetic a priori propositions of the “general doctrine of motion” are possible. To take each in turn. (a) Save by reference to time the conception of motion is self-contradictory. It involves the ascription to one and the same thing of contradictory predicates, e.g. that an object both is and is not in a certain place. From this fact, that time makes possible what is not possible in pure conception, Kant, in his earlier rationalistic period, had derived a proof of the subjectivity of time.[504] (b) In 1786 in the Metaphysical First Principles of Natural Science Kant had developed the fundamental principles of the general science of motion. He takes the opportunity of the second edition (1787) of the Critique to assign this place to them in his general system. The implication is that the doctrine of motion stands to time in the relation in which geometry stands to space. Kant is probably here replying, as Vaihinger has suggested,[505] to an objection made by Garve to the first edition, that no science, corresponding to geometry, is based on the intuition of time. For two reasons, however, the analogy between mechanics and geometry breaks down. In the first place, the conception of motion is empirical; and in the second place, it presupposes space as well as time.[506]

Kant elsewhere explicitly disavows this view that the science of motion is based on time. He had already done so in the preceding year (1786) in the Metaphysical First{128} Principles. He there points out[507] that as time has only one dimension, mathematics is not applicable to the phenomena of inner sense. At most we can determine in regard to them (in addition, of course, to the two axioms already cited) only the law that all these changes are continuous. Also in Kant’s Ueber Philosophie überhaupt (written some time between 1780 and 1790, and very probably in or about the year 1789) we find the following utterance:

“The general doctrine of time, unlike the pure doctrine of space (geometry), does not yield sufficient material for a whole science.”[508]

Why, then, should Kant in 1787 have so inconsistently departed from his own teaching? This is a question to which I can find no answer. Apparently without reason, and contrary to his more abiding judgment, he here repeats the suggestion which he had casually thrown out in the Dissertation[509] of 1770:

“Pure mathematics treats of space in geometry and of time in pure mechanics.”

But in the Dissertation the point is only touched upon in passing. The context permits of the interpretation that while geometry deals with space, mechanics deals with time in addition to space.


In the Dissertation, and again in the chapter on Schematism in the Critique itself, still another view is suggested, namely, that the science of arithmetic is also concerned with the intuition of time. The passage just quoted from the Dissertation proceeds as follows:

“Pure mathematics treats of space in geometry and of time in pure mechanics. To these has to be added a certain concept which is in itself intellectual, but which demands for its concrete actualisation (actuatio) the auxiliary notions of time and space (in the successive addition and in the juxtaposition of a plurality). This is the concept of number which is dealt with in Arithmetic.”[510]

This view of arithmetic is to be found in both editions of the Critique. Arithmetic depends upon the synthetic activity{129} of the understanding; the conceptual element is absolutely essential.

“Our counting (as is easily seen in the case of large numbers) is a synthesis according to concepts, because it is executed according to a common ground of unity, as, for instance, the decade (Dekadik).”[511] “The pure image ... of all objects of the senses in general is time. But the pure schema of quantity, in so far as it is a concept of the understanding, is number, a representation which combines the successive addition of one to one (homogeneous). Thus number is nothing but the unity of the synthesis of the manifold of a homogeneous intuition in general, whereby I generate time itself in the apprehension of the intuition.”[512]

This is also the teaching of the Methodology.[513] Now it may be observed that in none of these passages is arithmetic declared to be the science of time, or even to be based on the intuition of time. In 1783, however, in the Prolegomena, Kant expresses himself in much more ambiguous terms, for his words imply that there is a parallelism between geometry and arithmetic.

“Geometry is based upon the pure intuition of space. Arithmetic produces its concepts of number through successive addition of units in time, and pure mechanics especially can produce its concepts of motion only by means of the representation of time.”[514]

The passage is by no means explicit; the “especially” (vornehmlich) seems to indicate a feeling on Kant’s part that the description which he is giving of arithmetic is not really satisfactory. Unfortunately this casual statement, though never repeated by Kant in any of his other writings, was developed by Schulze in his Erläuterungen.

“Since geometry has space and arithmetic has counting as its object (and counting can only take place by means of time), it is evident in what manner geometry and arithmetic, that is to say pure mathematics, is possible.”[515]


Largely, as it would seem,[516] through Schulze, whose Erläuterungen did much to spread Kant’s teaching, this view came to be the current understanding of Kant’s position. The nature of arithmetic, as thus popularly interpreted, is expounded by Schopenhauer in the following terms:

“In time every moment is conditioned by the preceding. The ground of existence, as law of the sequence, is thus simple, because time has only one dimension, and no manifoldness of relations can be possible in it. Every moment is conditioned by the preceding; only through the latter can we attain to the former; only because the latter was, and has elapsed, does the former now exist. All counting rests upon this nexus of the parts of time; its words merely serve to mark the single steps of the succession. This is true of the whole of arithmetic, which throughout teaches nothing but the methodical abbreviations of counting. Every number presupposes the preceding numbers as grounds of its existence; I can only reach them through all the preceding, and only by means of this insight into the ground of its existence do I know that, where ten are, there are also eight, six, four.”[517]

Schulze was at once challenged to show that this was really Kant’s teaching, and the passage which he cited was Kant’s definition of the schema of number, above quoted.[518] It is therefore advisable that we should briefly discuss the many difficulties which this passage involves. What does Kant mean by asserting that in the apprehension of number we generate time? Does he merely mean that time is required for the process of counting? Counting is a process through which numerical relations are discovered; and it undoubtedly occupies time. But so do all processes of apprehension, in the study of geometry no less than of arithmetic. That this is not Kant’s meaning, and that it is not even what Schulze, notwithstanding his seemingly explicit mode of statement, intends to assert, is clearly shown by a letter written by Kant to Schulze in November 1788. Schulze, it appears, had spoken of this very matter.

Time, as you justly remark, has no influence upon the properties of numbers (as pure determinations of quantity), such as it may have upon the nature of those changes (of quantity) which are possible only in connection with a specific property of inner sense and its form (time). The science of number, notwithstanding the succession which every construction of quantity demands, is a pure intellectual synthesis which we represent to ourselves in thought. But so far as quanta are to be numerically determined, they must be given to us{131} in such a way that we can apprehend their intuition in successive order, and such that their apprehension can be subject to time....”[519]

No more definite statement could be desired of the fact that though in arithmetical science as in other fields of study our processes of apprehension are subject to time, the quantitative relations determined by the science are independent of time and are intellectually apprehended.

But if the above psychological interpretation of Kant’s teaching is untenable, how is his position to be defined? We must bear in mind the doctrine which Kant had already developed in his pre-Critical period, that mathematical differs from philosophical knowledge in that its concepts can have concrete individual form.[520] In the Critique this difference is expressed in the statement that the mathematical sciences alone are able to construct their concepts. And as they are pure mathematical sciences, this construction is supposed to take place by means of the a priori manifold of space and of time. Now though Kant had a fairly definite notion of what he meant by the construction of geometrical figures in space, his various utterances seem to show that in regard to the nature of arithmetical and algebraic construction he had never really attempted to arrive at any precision of view. To judge by the passage already quoted[521] from the Dissertation, Kant regarded space as no less necessary than time to the construction or intuition of number. ”[The intellectual concept of number] demands for its concrete actualisation the auxiliary notions of time and space (in the successive addition and in the juxtaposition of a plurality)” A similar view appears in the Critique in A 140 = B 179 and in B 15. In conformity, however, with the general requirements of his doctrine of Schematism, Kant defines the schema of number in exclusive reference to time; and, as we have noted, it is to this definition that Schulze appeals in support of his view of arithmetic as the science of counting and therefore of time. It at least shows that Kant perceived some form of connection to exist between arithmetic and time. But in this matter Kant’s position was probably simply a corollary from his general view of the nature of mathematical science, and in particular of his view of geometry, the “exemplar”[522] of all the others. Mathematical science, as such, is based on intuition;[523] therefore arithmetic, which is one of its departments,{132} must be so likewise. No attempt, however, is made to define the nature of the intuitions in which it has its source. Sympathetically interpreted, his statements may be taken as suggesting that arithmetic is the study of series which find concrete expression in the order of sequent times. The following estimate, given by Cassirer,[524] does ample justice both to the true and to the false elements in Kant’s doctrine.

”[Even discounting Kant’s insistence upon the conceptual character of arithmetical science, and] allowing that he derives arithmetical concepts and propositions from the pure intuition of time, this teaching, to whatever objections it may lie open, has certainly not the merely psychological meaning which the majority of its critics have ascribed to it. If it contained only the trivial thought, that the empirical act of counting requires time, it would be completely refuted by the familiar objection which B. Beneke has formulated: ‘The fact that time elapses in the process of counting can prove nothing; for what is there over which time does not flow?’ It is easily seen that Kant is only concerned with the ‘transcendental’ determination of the concept of time, according to which it appears as the type of an ordered sequence. William [Rowan] Hamilton, who adopts Kant’s doctrine, has defined algebra as ‘science of pure time or order in progression.’ That the whole content of arithmetical concepts can really be obtained from the fundamental concept of order in unbroken development, is completely confirmed by Russell’s exposition. As against the Kantian theory it must, of course, be emphasised, that it is not the concrete form of time intuition which constitutes the ground of the concept of number, but that on the contrary the pure logical concepts of sequence and of order are already implicitly contained and embodied in that concrete form.”

Much of the unsatisfactoriness of Kant’s argument is traceable to his mode of conceiving the “construction”[525] of mathematical concepts. All concepts, he seems to hold, even those of geometry and arithmetic, are abstract class concepts—the concept of triangle representing the properties common to all triangles, and the concept of seven the properties common to all groups that are seven. Mathematical concepts differ, however, from other concepts in that they are capable of a priori construction, that is, of having their objects represented in pure intuition. Now this is an extremely unfortunate mode of statement. It implies that mathematical concepts have a dual mode of existence, first as abstracted, and secondly as constructed. Such a position is not tenable. The concept of seven, in its primary form, is not abstracted from a variety of particular groups of{133} seven; it is already involved in the apprehension of each of them as being seven. Nor is it a concept that is itself constructed. It may perhaps be described as being the representation of something constructed; but that something is not itself. It represents the process or method generative of the complex for which it stands. Thus Kant’s distinction between the intuitive nature of mathematical knowledge and the merely discursive character of conceptual knowledge is at once inspired by the very important distinction between the product of construction and the product of abstraction, and yet at the same time is also obscured by the quite inadequate manner in which that latter distinction has been formulated. Kant has again adhered to the older logic even in the very act of revising its conclusions; and in so doing he has sacrificed the Critical doctrines of the Analytic to the pre-Critical teaching of the Dissertation and Aesthetic. Mathematical concepts are of the same general type as the categories; their primary function is not to clarify intuitions, but to make them possible. They are derivable from intuition only in so far as they have contributed to its constitution. If intuition contains factors additional to the concepts through which it is interpreted, these factors must remain outside the realm of mathematical science, until such time as conceptual analysis has proved itself capable of further extension.

I may now summarise this general discussion. Though Kant in the first edition of the Critique had spoken of the mathematical sciences as based upon the intuition of space and time, he had not, despite his constant tendency to conceive space and time as parallel forms of existence, based any separate mathematical discipline upon time. His definition of number, in the chapter on Schematism, had recognised the essentially conceptual character of arithmetic, and had connected it with time only in a quite indirect manner. A passage in the Prolegomena is the one place in all Kant’s writings in which he would seem to assert, though in brief and quite indefinite terms, that arithmetic is related to time as geometry is related to space. No such view of arithmetic is to be found in the second edition of the Critique. In the transcendental exposition of time, added in the second edition, only pure mechanics is mentioned. This would seem to indicate that Kant had made the above statement carelessly, without due thought, and that on further reflection he found himself unable to stand by it. The omission is the more significant in that Kant refers to arithmetic in the passages added in the second edition Introduction. The teaching of these passages, apart from the asserted necessity of appealing{134} to fingers or points,[526] harmonises with the view so briefly outlined in the Analytic. Arithmetic is a conceptual science; though it finds in ordered sequence its intuitional material, it cannot be adequately defined as being the science of time.


These Conclusions do not run parallel with the corresponding Conclusions in regard to space. In the first paragraph there are two differences. (a) Kant takes account of a view not considered under space, viz. that time is a self-existing substance. He rejects it on a ground which is difficult to reconcile with his recognition of a manifold of intuition as well as a manifold of sense, namely that it would then be something real without being a real object. In A 39 = B 57 and B 70 Kant describes space and time, so conceived, as unendliche Undinge. (b) Kant introduces into his first Conclusion the argument[528] that only by conceiving time as the form of inner intuition can we justify a priori synthetic judgments in regard to objects.

Second Paragraph (Conclusion b).—This latter statement is repeated at the opening of the second Conclusion. The emphasis is no longer, however, upon the term “form” but upon the term “inner”; and Kant proceeds to make assertions which by no means follow from the five arguments, and which must be counted amongst the most difficult and controversial tenets of the whole Critique. (a) Time is not a determination of outer appearances. For it belongs neither to their shape nor to their position—and prudently at this point the property of motion is smuggled out of view under cover of an etc. Time does not determine the relation of appearances to one another, but only the relation of representations in our inner state.[529] It is the form only of the intuition of ourselves and of our inner state.[530] Obviously these are assertions which Kant cannot possibly hold to in this unqualified form. In the very next paragraph they are modified and restated. (b) As this inner intuition supplies no shape (Gestalt), we seek to make good this deficiency by means of analogies. We represent the time-sequence through a line{135} progressing to infinity in which the manifold constitutes a series of only one dimension. From the properties of this line, with the one exception that its parts are simultaneous whereas those of time are always successive, we conclude to all the properties of time.

The wording of the passage seems to imply that such symbolisation of time through space is helpful but not indispensably necessary for its apprehension. That it is indispensably necessary is, however, the view to which Kant finally settled down.[531] But he has not yet come to clearness on this point. The passage has all the signs of having been written prior to the Analytic. Though Kant seems to have held consistently to the view that time has, in or by itself, only one dimension,[532] the difficulties involved drove him to recognise that this is true only of time as the order of our representations. It is not true of the objective time apprehended in and through our representations. When later Kant came to hold that consciousness of time is conditioned by consciousness of space, he apparently also adopted the view that, by reference to space, time indirectly acquires simultaneity as an additional mode. The objective spatial world is in time, but in a time which shows simultaneity as well as succession. In the Dissertation[533] Kant had criticised Leibniz and his followers for neglecting simultaneity, “the most important consequence of time.”

“Though time has only one dimension, yet the ubiquity of time (to employ Newton’s term), through which all things sensuously thinkable are at some time, adds another dimension to the quantity of actual things, in so far as they hang, as it were, upon the same point of time. For if we represent time by a straight line extended to infinity, and simultaneous things at any point of time by lines successively erected [perpendicular to the first line], the surface thus generated will represent the phenomenal world both as to substance and as to accidents.”

Similarly in A 182 = B 226 of the Critique Kant states that simultaneity is not a mode of time,[534] since none of the parts of time can be simultaneous, and yet also teaches in A 177 = B 219 that, as the order of appearances, time possesses in addition to succession the two modes, duration and simultaneity. The significance of this distinction between time as the order of our inner states, and time as the order of objective appearances, we shall consider immediately.

A connected question is as to whether or not Kant teaches the possibility of simultaneous apprehension. In the Aesthetic{136} and Dialectic he certainly does so. Space is given as containing coexisting parts, and[535] can be intuited as such without successive synthesis of its parts. In the Analytic, on the other hand, the opposite would seem to be implied.[536] The apprehension of a manifold can only be obtained through the successive addition or generation of its parts.

(c) Lastly, Kant argues that the fact that all the relations of time can be expressed in an outer intuition is proof that the representation of time is itself intuition. But surely if, as Kant later taught, time can be apprehended at all only in and through space, that, taken alone, would rather be a reason for denying it to be itself intuition. In any case it is difficult to follow Kant in his contention that the intuition of time is similar in general character to that of space.[537]

Third Paragraph (Conclusion c).—Kant now reopens the question as to the relation in which time stands to outer appearances. As already noted, he has argued in the beginning of the previous paragraph that it cannot be a determination of outer appearances, but only of representations in our inner state. External appearances, however, as Kant recognises, can be known only in and through representations. To that extent they belong to inner sense, and consequently (such is Kant’s argument) are themselves subject to time. Time, as the immediate condition of our representations, is also the mediate condition of appearances. Therefore, Kant concludes, “all appearances, i.e. all objects of the senses, are in time, and necessarily stand in time-relations.”

Now quite obviously this argument is invalid if the distinction between representations and their objects is a real and genuine one. For if so, it does not at all follow that because our representations of objects are in time that the objects themselves are in time. In other words, the argument is valid only from the standpoint of extreme subjectivism, according to which objects are, in Kant’s own phraseology, blosse Vorstellungen. But the argument is employed to establish a realist conclusion, that outer objects, as objects, stand in time-relations to one another. In contradiction of the previous paragraph he is now maintaining that time is a determination of outer appearances, and that it reveals itself in the motion of bodies as well as in the flux of our inner states.{137}

The distinction between representations and their objects also makes it possible for Kant both to assert and to deny that simultaneity is a mode of time. “No two years can be coexistent. Time has only one dimension. But existence (das Dasein), measured through time, has two dimensions, succession and simultaneity.” There are, for Kant, two orders of time, subjective and objective. Recognition of the latter (emphasised and developed in the Analytic)[538] is, however, irreconcilable with his contention that time is merely the form of inner sense.

We have here one of the many objections to which Kant’s doctrine of time lies open. It is the most vulnerable tenet in his whole system. A mere list of the points which Kant leaves unsettled suffices to show how greatly he was troubled in his own mind by the problems to which it gives rise. (1) The nature of the a priori knowledge which time yields. Kant ascribes to this source sometimes only the two axioms in regard to time, sometimes pure mechanics, and sometimes also arithmetic. (2) Whether time only allows of, or whether it demands, representation through space. Sometimes Kant makes the one assertion, sometimes the other. (3) Whether it is possible to apprehend the coexistent without successive synthesis of its parts. This possibility is asserted in the Aesthetic and Dialectic, denied in the Analytic. (4) Whether simultaneity is a mode of time. (5) Whether, and in what manner, appearances of outer sense are in time. Kant’s answer to 4 and to 5 varies according as he identifies or distinguishes representations and empirical objects.

The manifold difficulties to which a theory of time thus lies open are probably the reason why Kant, in the Critique, reverses the order in which he had treated time and space in the Dissertation.[539] But the placing of space before time is none the less unfortunate. It greatly tends to conceal from the reader the central position which Kant has assigned to time in the Analytic. Consciousness of time is the fundamental fact, taken as bare fact, by reference to which Kant gains his transcendental proof of the categories and principles of understanding.[540] In the Analytic space, by comparison, falls very much into the background. A further reason for the reversal may have been Kant’s Newtonian view of geometry as the mathematical science par excellence.[541] In view of his formulation of the Critical problem as that of accounting for synthetic a priori judgments, he would then naturally be led to throw more emphasis on space.{138}

To sum up our main conclusions. Kant’s view of time as a form merely of inner sense, and as having only one dimension, connects with his subjectivism. His view of it as inhering in objects, and as having duration and simultaneity as two of its modes, is bound up with his phenomenalism. Further discussion of these difficulties must therefore be deferred until we are in a position to raise the more fundamental problem as to the nature of the distinction between a representation and its object.[542] Motion is not an inner state. Yet it involves time as directly as does the flow of our feelings and ideas. Kant’s assertion that “time can no more be intuited externally than space can be intuited as something in us,”[543] if taken quite literally, would involve both the subjectivist assertion that motion of bodies is non-existent, and also the phenomenalist contention that an extended object is altogether distinct from a representation.

The fourth and fifth paragraphs call for no detailed analysis.[544] Time is empirically real, transcendentally ideal—these terms having exactly the same meaning and scope as in reference to space.[545] The fourth sentence in the fifth paragraph is curiously inaccurate. As it stands, it would imply that time is given through the senses. In the concluding sentences Kant briefly summarises and applies the points raised in these fourth and fifth paragraphs.


First and Second Paragraphs.—Kant here replies to a criticism which, as he tells us in his letter of 1772 to Herz, was first made by Pastor Schulze and by Lambert.[546] In that letter the objection and Kant’s reply are stated as follows.

“In accordance with the testimony of inner sense, changes are something real. But they are only possible on the assumption of time. Time is, therefore, something real which belongs to the determinations of things in themselves. Why, said I to myself, do we not argue in a parallel manner: ‘Bodies are real, in accordance with the outer senses. But bodies are possible only under the condition of space. Space is, therefore, something objective and real which inheres in the things themselves.’ The cause [of this differential treatment of space and of time] is the observation that in respect to outer things we cannot infer from the reality of representations the reality of their objects, whereas in inner sense the thought or the existing of the thought and of myself are one{139} and the same. Herein lies the key to the difficulty. Undoubtedly I must think my own state under the form of time, and the form of the inner sensibility consequently gives me the appearance of changes. Now I do not deny that changes are something real any more than I deny that bodies are something real, but I thereby mean only that something real corresponds to the appearance. I may not even say the inner appearance undergoes change (verändere sich), for how could I observe this change unless it appeared to my inner sense? To the objection that this leads to the conclusion that all things in the world objectively and in themselves are unchangeable, I would reply that they are neither changeable nor unchangeable. As Baumgarten states in § 18 of his Metaphysica, the absolutely impossible is hypothetically neither possible nor impossible, since it cannot be mentally entertained under any condition whatsoever; so in similar manner the things of the world are objectively or in themselves neither in one and the same state nor in different states at different times, for thus understood [viz. as things in themselves] they are not represented in time at all.”[547]

Thus Kant’s contention, both in this letter and in the passage before us, is that even our inner states would not reveal change if they could be apprehended by us or by some other being apart from the subjective form of our inner sense. We may not say that our inner states undergo change, or that they succeed one another, but only that to us they necessarily appear as so doing.[548] Time is no more than subjectively real.[549] As Körner writes to Schiller: “Without time man would indeed exist but not appear. Not his reality but only his appearance is dependent upon the condition of time.” “Man is not, but only appears, when he undergoes change.”[550] The objects of inner sense stand in exactly the same position as those of outer sense. Both are appearances, and neither can be identified with the absolutely real. As Kant argues later in the Critique,[551] inner processes are not known with any greater certainty or immediacy than are outer objects; the reality of time as subjective proves its unreality in relation to things in themselves. The statement that the constitution of{140} things in themselves is “problematic” is an exceptional mode of expression for Kant. Usually—as indeed throughout the whole context of this passage[552]—he asserts that though things in themselves are unknowable, we can with absolute certainty maintain that they are neither in space nor in time. Upon this point we have already dwelt in discussing Trendelenburg’s controversy with Fischer.[553]

Third Paragraph.—The third and fourth paragraphs of this section ought to have had a separate heading. They summarise the total argument of the Aesthetic in regard to space as well as time, distinguish its tenets from those of Newton and of Leibniz, and draw a general conclusion. The summary follows the strict synthetic method. The opening sentences illustrate Kant’s failure to distinguish between the problems of pure and of applied mathematics, and also show how completely he tends to conceive mathematics as typified by geometry. The criticism of alternative views traverses the ground of the famous controversy between Leibniz and Clarke. Their Streitschriften were, as we have good circumstantial grounds for believing,[554] a chief influence in the development of Kant’s own views. Kant, who originally held the Leibnizian position, was by 1768[555] more or less converted to the Newtonian teaching, and in the Dissertation of 1770 developed his subjectivist standpoint with the conscious intention of retaining the advantages while remedying the defects of both alternatives.[556] For convenience we may limit the discussion to space. (a) The view propounded by Newton, and defended by Clarke, is that space has an existence in and by itself, independent alike of the mind which apprehends it and of the objects with which it is filled. (b) The view held by Leibniz is that space is an empirical concept abstracted from our confused sense-experience of the relations of real things.[557]

The criticism of (a) is twofold. First, it involves belief{141} in an eternal and infinite Unding. Secondly, it leads to metaphysical difficulties, especially in regard to the existence of God. If space is absolutely real, how is it to be reconciled with the omnipresence of God? Newton’s view of space as the sensorium Dei can hardly be regarded as satisfactory.

The objection to (b) is that it cannot account for the apodictic certainty of geometry, nor guarantee its application to experience. The concept of space, when regarded as of sensuous origin, is something that may distort (and according to the Leibnizian teaching does actually distort) what it professes to represent, and is something from which restrictions that hold in the natural world have been omitted.[558] As empirical, it cannot serve as basis for the universal and necessary judgments of mathematical science.[559]

The first view has, however, the advantage of keeping the sphere of appearances open for mathematical science. As space is infinite and all-comprehensive, its laws hold universally. The second view has the advantage of not subjecting reality to space conditions. These advantages are retained, while the objections are removed, by the teaching of the Aesthetic.{142}

Kant further criticises the former view in A 46 ff. = B 64 ff. There is no possibility of accounting for the a priori synthetic judgments of geometry save by assuming that space is the pure form of outer intuition. For though the Newtonian view will justify the assertion that the laws of space hold universally, it cannot explain how we come to know them a priori. And assuming, as Kant constantly does, that space cannot be both an a priori form of intuition and also independently real, he concludes that it is the former only.

In B 71 Kant also restates the metaphysical difficulties to which the Newtonian view lies open. In natural theology we deal with an existence which can never be the object of sensuous intuition, and which has to be freed from all conditions of space and time. This is impossible if space is so absolutely real that it would remain though all created things were annihilated.

Fourth Paragraph.—Space and time are the only two forms of sensibility; all other concepts belonging to the senses, such as motion and change, are empirical.[560] As Kant has himself stated, no reason can be given why space and time are the sole forms of our possible intuition:

“Other forms of intuition than space and time, ... even if they were possible, we cannot render in any way conceivable and comprehensible to ourselves, and even assuming that we could do so, they still would not belong to experience, the only kind of knowledge in which objects are given to us.”[561]

The further statement,[562] frequently repeated in the Critique, that time itself does not change, but only what is in time,[563] indicates the extent to which Kant has been influenced by the Newtonian receptacle view. As Bergson very justly points out, time, thus viewed as a homogeneous medium, is really being conceived on the analogy of space. “It is merely the phantom of space obsessing the reflective consciousness.”[564]



I. First Paragraph.—“To avoid all misapprehension” Kant proceeds to state “as clearly as possible” his view of sensuous knowledge. With this end in view he sets himself to enforce two main points: (a) that as space and time are only forms of sensibility, everything apprehended is only appearance; (b) that this is not a mere hypothesis but is completely certain. Kant expounds (a) indirectly through criticism of the opposing views of Leibniz and of Locke. But before doing so he makes in the next paragraph a twofold statement of his own conclusions.

Second Paragraph.—This paragraph states (a) that through intuition we can represent only appearances, not things in themselves, and (b) that the appearances thus known exist only in us. Both assertions have implications, the discussion of which must be deferred to the Analytic. The mention of the “relations of things by themselves” may, as Vaihinger suggests,[565] be a survival from the time when (as in the Dissertation[566]) Kant sought to reduce spatial to dynamical relations. The assertion that things in themselves are completely unknown to us goes beyond what the Aesthetic can establish and what Kant here requires to prove. His present thesis is only that no knowledge of things in themselves can be acquired either through the forms of space and time or through sensation; space and time are determined solely by our pure sensibility, and sensations by our empirical sensibility. Failure to recognise this is, in Kant’s view, one of the chief defects of the Leibnizian system.

Third and Fourth Paragraphs. Criticism of the Leibniz-Wolff Interpretation of Sensibility and of Appearance.—Leibniz vitiates both conceptions. Sensibility does not differ from thought in clearness but in content. It is a difference of kind.[567] They originate in different sources, and neither can by any transformation be reduced to the other.

“Even if an appearance could become completely transparent to us, such knowledge would remain toto coelo different from knowledge of the object in itself.”[568] “Through observation and analysis of appearances we penetrate to the secrets of nature, and no one can say how far this may in time extend.... [But however far we advance, we{144} shall never be able by means of] so ill-adapted an instrument of investigation [as our sensibility] to find anything except still other appearances, the non-sensuous cause of which we yet long to discover.”[569]

We should still know only in terms of the two inalienable forms of our sensibility.[570] The dualism of thought and sense can never be transcended by the human mind. By no extension of its sphere or perfecting of its insight can sensuous knowledge be transformed into a conceptual apprehension of purely intelligible entities.

Leibniz’s conception of appearances as things in themselves confusedly apprehended is equally false, and for the same reasons.[571] Appearance and reality are related as distinct existences, each of which has its own intrinsic character and content. Through the former there can be no hope of penetrating to the latter. Appearance is subjective in matter as well as in form. For Leibniz our knowledge of appearances is a confused knowledge of things in themselves. Properly viewed, it is the apprehension, whether distinct or confused, of objects which are never things in themselves. Sense-knowledge, such as we obtain in the science of geometry, has often the highest degree of clearness. Conceptual apprehension is all too frequently characterised by obscurity and indistinctness.

This criticism of Leibniz, as expounded in these two paragraphs, is thoroughly misleading if taken as an adequate statement of Kant’s view of the relations between sense and understanding, appearance and reality. These paragraphs are really a restatement of a passage in the Dissertation.

“It will thus be seen that we express the nature of the sensuous very inappropriately when we assert that it is the more confusedly known, and the nature of the intellectual when we describe it as the distinctly known. For these are merely logical distinctions, and obviously have nothing to do with the given facts which underlie all logical comparison. The sensuous may be absolutely distinct, and the intellectual extremely confused. That is shown on the one hand in geometry, the prototype of sensuous knowledge, and on the other in metaphysics, the instrument of all intellectual enquiry. Every one knows how zealously metaphysics has striven to dispel the mists of confusion which cloud the minds of men at large and yet has not{145} always attained the happy results of the former science. Nevertheless each of these kinds of knowledge preserves the mark of the stock from which it has sprung. The former, however distinct, is on account of its origin entitled sensuous, while the latter, however confused, remains intellectual—as e.g. the moral concepts, which are known not by way of experience, but through the pure intellect itself. I fear, however, that Wolff by this distinction between the sensuous and the intellectual, which for him is merely logical, has checked, perhaps wholly (to the great detriment of philosophy), that noblest enterprise of antiquity, the investigation of the nature of phenomena and noumena, turning men’s minds from such enquiries to what are very frequently only logical subleties.”[572]

The paragraphs before us give expression only to what is common to the Dissertation and to the Critique, and do so entirely from the standpoint of the Dissertation. Thus the illustration of the conception of “right” implies that things in themselves can be known through the understanding. The conception, as Kant says, represents “a moral property which belongs to actions in and by themselves.” Similarly, in distinguishing the sensuous from “the intellectual,” he says that through the former we do not apprehend things in themselves, thus implying that things in themselves can be known through the pure intellect. The view developed in the Analytic, alike of sensibility and of appearance, is radically different. Sensibility and understanding may have a common source; and both are indispensably necessary for the apprehension of appearance. Neither can function save in co-operation with the other. Appearance does not differ from reality solely through its sensuous content and form, but also in the intellectual order or dispensation to which it is subject. But in the very act of thus deepening the gulf between appearance and reality by counting even understanding as contributing to the knowledge only of the former, he was brought back to a position that has kinship with the Leibnizian view of their interrelation. Since understanding is just as essential as sensibility to the apprehension of appearances, and since understanding differs from sensibility in the universality of its range, it enables us to view appearances in their relation to ultimate reality, and so to apprehend them as being, however subjective or phenomenal, ways in which the thing in itself presents itself to us. Such a view is, however, on Kant’s principles, quite consistent with the further contention, that appearance does not differ from reality in a merely logical manner. Factors that are peculiar to the realm of appearance have intervened to transform the real;{146} and in consequence even completed knowledge of the phenomenal—if such can be conceived as possible—would not be equivalent to knowledge of things in themselves.

Fifth Paragraph. Criticism of Locke’s View of Appearance.—This paragraph discusses Locke’s doctrine[573] that the secondary qualities are subjective, and that in the primary qualities we possess true knowledge of things in themselves. The distinction is drawn upon empirical grounds, namely, that while certain qualities are uniform for more than one sense, and belong to objects under all conditions, others are peculiar to the different senses, and arise only through the accidental relation of objects to the special senses.[574] This distinction is, Kant says, entirely justified from the physical standpoint.[575] A rainbow is an appearance of which the raindrops constitute the true empirical reality. But Locke and his followers interpret this distinction wrongly. They ignore the more fundamental transcendental (i.e. metaphysical) distinction between empirical reality and the thing in itself. From the transcendental standpoint the raindrops are themselves merely appearance. Even their round shape, and the very space in which they fall; are only modifications of our sensuous intuition. The ‘transcendental object’[576] remains unknown to us.

When Kant thus declares that the distinction between primary and secondary qualities is justified (richtig) from the physical standpoint, he is again[577] speaking from a phenomenalist point of view. And it may be noted that in developing his transcendental distinction he does not describe the raindrops as mere representations. His phrase is much more indefinite. They are “modifications or fundamental forms (Grundlagen) of our sensuous intuition.”

Kant does not here criticise the view of sensibility which underlies Locke’s view of appearance. But he does so in A 271 = B 327, completing the parallel and contrast between Leibniz and Locke.

“Leibniz intellectualised appearances, just as Locke, according to his system of noogony (if I may be allowed these expressions), sensualised all concepts of the understanding, i.e. interpreted them as simply empirical or abstracted concepts of reflection. Instead of interpreting understanding and sensibility as two quite different sources of representations, which yet can supply objectively valid judgments of{147} things only in conjunction with each other, each of these great men holds only to one of the two, viewing it as in immediate relation to things in themselves. The other faculty is regarded as serving only to confuse or to order the representations which this selected faculty yields.”[578]

Proof that the above View of Space and Time is not a mere Hypothesis, but completely certain.[579]—The proof, which as here recapitulated and developed follows the analytic method, has already been considered in connection with A 39 = B 56. It proceeds upon the assumption that space cannot be both an a priori form of intuition and also independently real. The argument as a whole lacks clearness owing to Kant’s failure to distinguish between the problems of pure and applied geometry, between pure intuition and form of intuition. This is especially obvious in the very unfortunate and misleading second application of the triangle illustration.[580] Kant’s tendency to conceive mathematical science almost exclusively in terms of geometry is likewise illustrated.

“There is in regard to both [space and time] a large number of a priori apodictic and synthetic propositions. This is especially true of space, which for this reason will be our chief illustration in this enquiry.”[581]

II. Paragraphs added in the Second Edition.[582]—Kant proceeds to offer further proof of the ideality of the appearances (a) of outer and (b) of inner sense. Such proof he finds in the fact that these appearances consist solely of relations. (a) Outer appearances reduce without remainder to relations of position in intuition (i.e. of extension), of change of position (motion), and to the laws which express in merely relational terms the motive forces by which such change is determined. What it is that is thus present in space, or what the dynamic agencies may be to which the motion is due, is never revealed. But a real existent (Sache an sich) can never be known through mere relations. Outer sense consequently reveals through its representations only the relation of an object to the subject, not the intrinsic inner nature of the object in itself (Object an sich). Kant’s avoidance of the term Ding an sich may be noted.[583]


(b) The same holds true of inner sense, not only because the representations of outer sense constitute its proper (eigentlichen) material, but also because time, in which these are set, contains only relations of succession, coexistence, and duration. This time (which as consisting only of relations can be nothing but a form[584]) is itself, in turn, a mere relation. It is only the manner in which through its own activity the mind is affected by itself. But in order to be affected by itself it must have receptivity, in other words, sensibility. Time, consequently, must be regarded as the form of this inner sense.

That everything represented in time, like that which is represented in space, consists solely of relations, Kant does not, however, attempt to prove. He is satisfied with repeating the conclusion reached in the first edition of the Aesthetic, that, as time is the object of a sense, it must of necessity be appearance. This, like everything which Kant wrote upon inner sense, is profoundly unsatisfactory. The obscurities of his argument are not to be excused on the ground that “the difficulty, how a subject can have an internal intuition of itself, is common to every theory.” For no great thinker,[585] except Locke, has attempted to interpret inner consciousness on the analogy of the senses. Discussion of the doctrine must meantime be deferred.[586]

III. B 69.—Kant here formulates the important distinction between appearance (Erscheinung) and illusion (Schein). The main text is clear so far as it goes; but the appended note is thoroughly confused. Together they contain no less than three distinct and conflicting views of illusion.[587] According to the main text, Schein signifies a representation, such as may occur in a dream, to which nothing real corresponds. Erscheinung, on the other hand, is always the appearance of a given object; but since the qualities of that object depend solely on our mode of intuition, we have to distinguish the object as appearance from the object as thing in itself.

”[Every appearance] has two sides, the one by which the object is viewed in and by itself, ... the other by which the form of the intuition of the object is taken into account....”[588]

Obviously, when illusion is defined in the above manner,{149} the assertion that objects in space are mere appearances cannot be taken as meaning that they are illusory.

But this view of illusion is peculiar to the passage before us and to A 38 = B 55. It occurs nowhere else, either in the Critique or in the Prolegomena; and it is not, as Kant has himself admitted,[589] really relevant to the purposes of the Critique. The issues are more adequately faced in the appended note, which, however, at the same time, shows very clearly that Kant has not yet properly disentangled their various strands. The above definition of appearance is too wide. It covers illusory sense perception as well as appearance proper. The further qualification must be added, that the predicates of appearance are constant and are inseparable from its representation. Thus the space predicates can be asserted of any external object. Redness and scent can be ascribed to the rose. All of these are genuine appearances. If, on the other hand, the two handles, as observed by Galileo, are attributed to Saturn, roundness to a distant square tower, bentness to a straight stick inserted in water, the result is mere illusion. The predicates, in such cases, do not stand the test of further observation or of the employment of other senses. Only in a certain position of its rings, relatively to the observer, does Saturn seem (scheint) to have two handles. The distant tower only seems to be round. The stick only seems to be bent. But the rose is extended and is red. Obviously Kant is no longer viewing Schein as equivalent to a merely mental image. It now receives a second meaning. It is illusion in the modern, psychological sense. It signifies an abnormal perception of an actually present object. The distinction between appearance and illusion is now reduced to a merely relative difference in constancy and universality of appearance. Saturn necessarily appears to Galileo as possessing two handles. A square tower viewed from the distance cannot appear to the human eye otherwise than round. A stick inserted in water must appear bent. If, however, Saturn be viewed under more favourable conditions, if the distance from the tower be diminished, if the stick be removed from the water, the empirical object will appear in a manner more in harmony with the possible or actual experiences of touch. The distinction is practical, rather than theoretical, in its justification. It says only that certain sets of conditions may be expected to remain uniform;{150} those, for instance, physical, physiological, and psychical, which cause a rose to appear red. Other sets of conditions, such as those which cause the stick to appear bent, are exceptional, and for that reason the bentness may be discounted as illusion. Among the relatively constant are the space and time properties of bodies. To employ the terms of the main text, it is not only by illusion that bodies seem to exist outside me; they actually are there.

So long as we keep to the sphere of ordinary experience, and require no greater exactitude than practical life demands, this distinction is, of course, both important and valid. But Kant, by his references to Saturn, raises considerations which, if faced, must complicate the problem and place it upon an entirely different plane. If, in view of scientific requirements, the conditions of observation are more rigorously formulated, and if by artificial instruments of scientific precision we modify the perceptions of our human senses, what before was ranked as appearance becomes illusion; and no limit can be set to the transformations which even our most normal human experiences may thus be made to undergo. Even the most constant perceptions then yield to variation. The most that can be asserted is that throughout all change in the conditions of observation objects still continue to possess, in however new and revolutionary a fashion, some kind of space and time predicates. The application of this more rigorous scientific standard of appearance thus leads to a fourfold distinction between ultimate reality, scientific appearances, the appearances of ordinary consciousness, and the illusions of ordinary consciousness. The appearances of practical life are the illusions of science, and the appearances of science would similarly be illusions to any being who through ‘intuitive understanding’ could apprehend things in themselves.

But if the distinction between appearance and illusion is thus merely relative to the varying nature of the conditions under which observation takes place, it can afford no sufficient answer to the criticisms which Kant is here professing to meet. Kant has in view those critics (such as Lambert, Mendelssohn, and Garve) who had objected that if bodies in space are representations existing, as he so often asserts, only “within us,” their appearing to exist “outside us” is a complete illusion. These critics have, indeed, found a vulnerable point in Kant’s teaching. The only way in which he can effectively meet it is by frank recognition and development of the phenomenalism with which his subjectivism comes into so frequent conflict.[590] That certain perceptions are{151} more constant than others does not prove that all alike may not be classed as illusory. The criticism concerns only the reality of extended objects. From Kant’s own extreme subjectivist position they are illusions of the most thoroughgoing kind. If, as Kant so frequently maintains, objects are representations and exist only “within us,” their existence “outside us” must be denied. The criticism can be met only if Kant is prepared consistently to formulate and defend his own alternative teaching, that sensations arise through the action of external objects upon the sense-organs, and that the world of physical science has consequently a reality not reducible to mere representations in the individual mind.

It may be objected that Kant has in the main text cited one essential difference between his position and that which is being ascribed to him. Extended objects, though mere representations, are yet due to, and conditioned by, things in themselves. They are illusory only in regard to their properties, not in regard to their existence. But this distinction is not really relevant. The criticism, as just stated, is directed only against Kant’s view of space. The fact that the spatial world is a grounded and necessary illusion is not strictly relevant to the matter in dispute. Kant has, indeed, elsewhere, himself admitted the justice of the criticism. In A 780 = B 808 he cites as a possible hypothesis, entirely in harmony with his main results, though not in any degree established by them, the view

“that this life is an appearance only, that is, a sensuous representation of purely spiritual life, and that the whole sensible world is a mere image (ein blosses Bild) which hovers before our present mode of knowledge, and like a dream has in itself no objective reality.”

Kant’s reply is thus really only verbal. He claims that illusion, if constant, has earned the right to be called appearance. He accepts the criticism, but restates it in his own terms. The underlying phenomenalism which colours the position in his own thoughts, and for which he has not been able to find any quite satisfactory formulation, is the sole possible justification, if any such exists, for his contention that the criticism does not apply. Such phenomenalism crops out in the sentence, already partially quoted:

“If I assert that the quality of space and time, according to which, as a condition of their existence, I posit both external objects and my own soul, lies in my mode of intuition and not in these objects in themselves, I am not saying that only by illusion do{152} bodies seem to exist outside me or my soul to be given in my self-consciousness.”[591]

But, so far, I have simplified Kant’s argument by leaving out of account a third and entirely different view of illusion which is likewise formulated in the appended note. In the middle of the second sentence, and in the last sentence, illusion is defined as the attribution to the thing in itself of what belongs to it only in its relation to the senses. Illusion lies not in the object apprehended, but only in the judgment which we pass upon it. It is due, not to sense, but to understanding.[592] Viewing illusion in this way, Kant is enabled to maintain that his critics are guilty of “an unpardonable and almost intentional misconception,”[593] since this is the very fallacy which he himself has been most concerned to attack. As he has constantly insisted, appearance is appearance just because it can never be a revelation of the thing in itself.

Now the introduction of this third view reduces the argument of the appended note to complete confusion. Its first occurrence as a parenthesis in a sentence which is stating an opposed view would seem to indicate that the note has been carelessly recast. Originally containing only a statement of the second view, Kant has connected therewith the view which he had already formulated in the first edition and in the Prolegomena. But the two views cannot be combined. By the former definition, illusion is necessitated but abnormal perception; according to the latter, it is a preventable error of our conscious judgment. The opposite of illusion is in the one case appearance, in the other truth. The retention of the reference to Saturn, in the statement of the third view at the end of the note, is further evidence of hasty recasting. While the rose and the extended objects are there treated as also things in themselves, Saturn is taken only in its phenomenal existence. In view of the general confusion, it is a minor inconsistency that Kant should here maintain, in direct opposition to A 28-9, that secondary qualities can be attributed to the empirical object.

This passage from the second edition is a development of Prolegomena, § 13, iii. Kant there employs the term appearance in a quite indefinite manner. For the most part he seems to mean by it any and every sense-experience, whether normal or abnormal, and even to include under it dream images.{153} But it is also employed in the second of the above meanings, as signifying those sense-perceptions which harmonise with general experience. Illusion is throughout employed in the third of the above meanings. Kant’s illustration, that of the apparently retrograde movements of the planets, necessitates a distinction between apparent and real motion in space, and consequently leads to the fruitful distinction noted above. Kant gives, however, no sign that he is conscious of the complicated problems involved.

In the interval between the Prolegomena (1783) and the second edition of the Critique (1787) Mendelssohn had published (1785) his Morgenstunden. In its introduction, entitled Vorerkenntniss von Wahrheit, Schein und Irrthum,[594] he very carefully distinguishes between illusion (Sinnenschein) and error of judgment (Irrthum). This introduction Kant had read. In a letter to Schütz[595] he cites it by title, and praises it as “acute, original, and of exemplary clearness.” It is therefore the more inexcusable that he should again in the second edition of the Critique have confused these two so radically different meanings of the term Schein. Mendelssohn, however, drew no distinction between Schein and Erscheinung. They were then used as practically synonymous,[596] though of course Schein was the stronger term. Kant seems to have been the first to distinguish them sharply and to attempt to define the one in opposition to the other. But the very fact that Erscheinung and Schein were currently employed as equivalent terms, and that the distinction, though one of his own drawing, had been mentioned only in the most cursory manner in the first edition of the Critique,[597] removes all justification for his retort upon his critics of “unpardonable misconception.” His anger was really due, not to the objection in itself, but to the implied comparison of his position to that of Berkeley. Such comparison never failed to arouse Kant’s wrath. For however much this accusation might be justified by his own frequent lapses into subjectivism of the most extreme type, even its partial truth was more than he was willing to admit. Berkeley represents in his eyes, not merely a subjectivist interpretation of the outer world, but the almost diametrical opposite of everything for which he himself stood. Discussion of Kant’s relation to Berkeley had best, however, be introduced through consideration of{154} the passage immediately following in which Kant refers to Berkeley by name.

III. (Second Part) B 70.—Kant urges that his doctrine of the ideality of space and time, so far from reducing objects to mere illusion, is the sole means of defending their genuine reality. If space and time had an independent existence, they would have to be regarded as more real than the bodies which occupy them. For on this view space and time would continue to exist even if all their contents were removed; they would be antecedent necessary conditions of all other existences. But space and time thus interpreted are impossible conceptions.[598] The reality of bodies is thereby made to depend upon Undinge. If this were the sole alternative, “the good Bishop Berkeley [could] not be blamed for degrading bodies to mere illusion.” We should, Kant maintains, have to proceed still further, denying even our own existence. For had Berkeley taken account of time as well as of space, a similar argument, consistently developed in regard to time, would have constrained him to reduce the self to the level of mere illusion. Belief in the reality of things in themselves, whether spiritual or material, is defensible only if space and time be viewed as subjective. In other words, Berkeley’s idealism is an inevitable consequence of a realist view of space. But it is also its reductio ad absurdum.

[“Berkeley in his dogmatic idealism] maintains that space, with all the things of which it is the inseparable condition, is something impossible in itself, and he therefore regards the things in space as merely imaginary entities (Einbildungen). Dogmatic idealism is inevitable if space be interpreted as a property which belongs to things in themselves. For, when so regarded, space, and everything to which it serves as condition, is a non-entity (Unding). The ground upon which this idealism rests we have removed in the Transcendental Aesthetic.”[599]

The term Schein is not employed throughout this passage in either of the two meanings of the appended note, but in that of the main text. It signifies a representation, to which no existence corresponds.{155}


By idealism[600] Kant means any and every system which maintains that the sensible world does not exist in the form in which it presents itself to us. The position is typified in Kant’s mind by the Eleatics, by Plato, and by Descartes, all of whom are rationalists. With the denial of reality to sense-appearances they combine a belief in the possibility of rationally comprehending its supersensible basis. Failing to appreciate the true nature of the sensible, they misunderstand the character of geometrical science, and falsely ascribe to pure understanding a power of intellectual intuition. Kant’s criticisms of Berkeley show very clearly that it is this more general position which he has chiefly in view. To Berkeley Kant objects that only in sense-experience is there truth, that it is sensibility, not understanding, which possesses the power of a priori intuition, and that through pure understanding, acting in independence of sensibility, no knowledge of any kind can be acquired. In other words, Kant classes Berkeley with the rationalists. And, as we have already seen, he even goes the length of regarding Berkeley’s position as the reductio ad absurdum of the realist view of space. Kant does, indeed, recognise[601] that Berkeley differs from the other idealists, in holding an empirical view of space, and consequently of geometry, but this does not prevent Kant from maintaining that Berkeley’s thinking is influenced by certain fundamental implications of the realist position. Berkeley’s insight—such would seem to be Kant’s line of argument—is perverted by the very view which he is attacking. Berkeley appreciates only what is false in the Cartesian view of space; he is blind to the important element of truth which it contains. Empiricist though he be, he has no wider conception of the function and powers of sensibility than have the realists from whom he separates himself off; and in order to comprehend those existences to which alone he is willing to allow true reality, he has therefore, like the rationalists, to fall back upon pure reason.[602]


That Kant’s criticism of Berkeley should be extremely external is not, therefore, surprising. He is interested in Berkeley’s positive teaching only in so far as it enables him to illustrate the evil tendencies of a mistaken idealism, which starts from a false view of the functions of sensibility and of understanding, and of the nature of space and time. The key to the true idealism lies, he claims, in the Critical problem, how a priori synthetic judgments can be possible. This is the fundamental problem of metaphysics, and until it has been formulated and answered no advance can be made.

“My so-called (Critical) idealism is thus quite peculiar in that it overthrows ordinary idealism, and that through it alone a priori cognition, even that of geometry, attains objective reality, a thing which even the keenest realist could not assert till I had proved the ideality of space and time.”[603]

In order to make Kant’s account of Berkeley’s teaching really comprehensible, we seem compelled to assume that he had never himself actually read any of Berkeley’s own writings. Kant’s acquaintance with the English language was most imperfect, and we have no evidence that he had ever read a single English book.[604] When he quotes Pope and Addison, he does so from German translations.[605] Subsequent to 1781 he could, indeed, have had access to Berkeley’s Dialogues between Hylas and Philonous[606] in a German translation; but in view of the account which he continues to give of Berkeley’s teaching, it does not seem likely[607] that he had availed himself of this opportunity. As to what the indirect sources of Kant’s knowledge of Berkeley may have been, we cannot decide with any certainty, but amongst them must undoubtedly be reckoned Hume’s statements in regard to Berkeley in the Enquiry,[608] and very probably also the references to Berkeley in Beattie’s Nature of Truth.[609] From{157} the former Kant would learn of Berkeley’s empirical view of space and also of the sceptical tendencies of his idealist teaching. From it he might also very naturally infer that Berkeley denies all reality to objects. By Beattie Kant would be confirmed in this latter view, and also in his contention that Berkeley is unable to supply a criterion for distinguishing between reality and dreams. Kant may also have received some impressions regarding Berkeley from Hamann.

To take Kant’s criticisms of Berkeley more in detail. In the first edition of the Critique[610] Kant passes two criticisms, without, however, mentioning Berkeley by name: first, that he overlooks the problem of time, and, like Descartes, ascribes complete reality to the objects of inner sense. This is the cause of a second error, namely, that he views the objects of outer sense as mere illusion (blosser Schein). Proceeding, Kant argues that inner and outer sense are really in the same position. Though they yield only appearances, these appearances are conditioned by things in themselves. Through this relation to things in themselves they are distinguished from all merely subjective images. Berkeley is again referred to in the fourth Paralogism.[611] His idealism is distinguished from that of Descartes. The one is dogmatic; the other is sceptical. The one denies the existence of matter; the other only doubts whether it is possible to prove it. Berkeley claims, indeed, that there are contradictions in the very conception of matter; and Kant remarks that this is an objection which he will have to deal with in the section on the Antinomies. But this promise Kant does not fulfil; and doubtless for the reason that, however unwilling he may be to make the admission, on this point his own teaching, especially in the Dialectic, frequently coincides with that of Berkeley. So little, indeed, is Kant concerned in the first edition to defend his position against the accusation of subjectivism, that in this same section he praises the sceptical idealist as a “benefactor of human reason.”

“He compels us, even in the smallest advances of ordinary experience, to keep on the watch, lest we consider as a well-earned possession what we perhaps obtain only in an illegitimate manner. We are now in a position to appreciate the value of the objections of the idealist. They drive us by main force, unless we mean to contradict ourselves in our commonest assertions, to view all our perceptions, whether we call them inner or outer, as a consciousness only of what is dependent on our sensibility. They also compel us to regard the outer objects of these perceptions not as things in{158} themselves, but only as representations, of which, as of every other representation, we can become immediately conscious, and which are entitled outer because they depend on what we call ‘outer sense’ whose intuition is space. Space itself, however, is nothing but an inner mode of representation in which certain perceptions are connected with one another.”[612]

These criticisms are restated in A 491-2 = B 519-20, with the further addition that in denying the existence of extended beings “the empirical idealist” removes the possibility of distinguishing between reality and dreams. This is a new criticism. Kant is no longer referring to the denial of unknowable things in themselves. He is now maintaining that only the Critical standpoint can supply an immanent criterion whereby real experiences may be distinguished from merely subjective happenings. This point is further insisted upon in the Prolegomena,[613] but is nowhere developed with any direct reference to Berkeley’s own personal teaching. Kant assumes as established that any such criterion must rest upon the a priori; and in this connection Berkeley is conveniently made to figure as a thoroughgoing empiricist.

The Critique, on its publication, was at once attacked, especially in the Garve-Feder review, as presenting an idealism similar to that of Berkeley. As Erdmann has shown, the original plan of the Prolegomena was largely modified in order to afford opportunity for reply to this “unpardonable and almost intentional misconception.”[614] Kant’s references to Berkeley, direct and indirect, now for the first time manifest a polemical tone, exaggerating in every possible way the difference between their points of view. Only the transcendental philosophy can establish the possibility of a priori knowledge, and so it alone can afford a criterion for distinguishing between realities and dreams. It alone will account for the possibility of geometrical science; Berkeley’s idealism would render the claims of that science wholly illusory. The Critical idealism transcends experience only so far as is required to discover the conditions which make empirical cognition possible; Berkeley’s idealism is ‘visionary’ and ‘mystical.’[615] Even sceptical idealism now comes in for severe handling. It may be called “dreaming idealism”; it makes things out of{159} mere representations, and like idealism in its dogmatic form it virtually denies the existence of the only true reality, that of things in themselves. Sceptical idealism misinterprets space by making it empirical, dogmatic idealism by regarding it as an attribute of the real. Both entirely ignore the problem of time. For these reasons they underestimate the powers of sensibility (to which space and time belong as a priori forms), and exaggerate those of pure understanding.

“The position of all genuine idealists from the Eleatics to Berkeley is contained in this formula: ‘All cognition through the senses and experience is nothing but mere illusion, and only in the ideas of pure understanding and Reason is there truth.’ The fundamental principle ruling all my idealism, on the contrary, is this: ‘All cognition of things solely from pure understanding or pure Reason is nothing but mere illusion and only in experience is there truth.’”[616]

This is an extremely inadequate statement of the Critical standpoint, but it excellently illustrates Kant’s perverse interpretation of Berkeley’s teaching.

To these criticisms Kant gives less heated but none the less explicit expression in the second edition of the Critique. He is now much more careful to avoid subjectivist modes of statement. His phenomenalist tendencies are reinforced, and come to clearer expression of all that they involve. The fourth Paralogism with its sympathetic treatment of empirical idealism is omitted, and in addition to the above passage Kant inserts a new section, entitled Refutation of Idealism, in which he states his position in a much more adequate manner.

IV. B 71.—Kant continues the argument of A 39.[617] If space and time condition all existence, they will condition even divine existence, and so must render God’s omniscience, which as such must be intuitive, not discursive, difficult of conception. Upon this point Kant is more explicit in the Dissertation.[618]

Whatever is, is somewhere and sometime, is a spurious axiom.... By this spurious principle all beings, even though they be known intellectually, are restricted in their existence by conditions of space and time. Philosophers therefore discuss every form of idle question regarding the locations in the corporeal universe of substances that are immaterial—and of which for that very reason there can be no sensuous intuition nor any possible spatial representation—or regarding{160} the seat of the soul, and the like. And since the sensuous mixes with the intellectual about as badly as square with round, it frequently happens that the one disputant appears as holding a sieve into which the other milks the he-goat. The presence of immaterial things in the corporeal world is virtual, not local, although it may conveniently be spoken of as local. Space contains the conditions of possible interaction only when it is between material bodies. What, however, in immaterial substances constitutes the external relations of force between them or between them and bodies, obviously eludes the human intellect.... But when men reach the conception of a highest and extra-mundane Being, words cannot describe the extent to which they are deluded by these shades that flit before the mind. They picture God as present in a place: they entangle Him in the world where He is supposed to fill all space at once. They hope to make up for the [spatial] limitation they thus impose by thinking of God’s place per eminentiam, i.e. as infinite. But to be present in different places at the same time is absolutely impossible, since different places are mutually external to one another, and consequently what is in several places is outside itself, and is therefore present to itself outside itself—which is a contradiction in terms. As to time, men have got into an inextricable maze by releasing it from the laws that govern sense knowledge, and what is more, transporting it beyond the confines of the world to the Being that dwells there, as a condition of His very existence. They thus torment their souls with absurd questions, for instance, why God did not fashion the world many centuries earlier. They persuade themselves that it is easily possible to conceive how God may discern present things, i.e. what is actual in the time in which He is. But they consider that it is difficult to comprehend how He should foresee the things about to be, i.e. the actual in the time in which He is not yet. They proceed as if the existence of the Necessary Being descended successively through all the moments of a supposed time, and having already exhausted part of His duration, foresaw the eternal life that still lies before Him together with the events which [will] occur simultaneously [with that future life of His]. All these speculations vanish like smoke when the notion of time has been rightly discerned.”

The references in B 71-2 to the intuitive understanding are among the many signs of Kant’s increased preoccupation, during the preparation of the second edition, with the problems which it raises. Such understanding is not sensuous, but intellectual; it is not derivative, but original; the object itself is created in the act of intuition. Or, as Kant’s position may perhaps be more adequately expressed, all of God’s activities are creative, and are inseparable from the non-sensuous intuition whereby both they and their products are apprehended by Him. Kant’s reason for again raising this point may be Mendelssohn’s theological defence of the reality{161} of space in his Morgenstunden.[619] Mendelssohn has there argued that just as knowledge of independent reality is confirmed by the agreement of different senses, and is rendered the more certain in proportion to the number of senses which support the belief, so the validity of our spatial perceptions is confirmed in proportion as men are found to agree in this type of experience with one another, with the animals, and with angelic beings. Such inductive inference will culminate in the proof that even the Supreme Being apprehends things in this same spatial manner.[620] Kant’s reply is that however general the intuition of space may be among finite beings, it is sensuous and derivative, and therefore must not be predicated of a Divine Being. For obvious reasons Kant has not felt called upon to point out the inadequacy of this inductive method to the solution of Critical problems. In A 42 Kant, arguing that our forms of intuition are subjective, claims that they do not necessarily belong to all beings, though they must belong to all men.[621] He is quite consistent in now maintaining[622] that their characteristics, as sensuous and derivative, do not necessarily preclude their being the common possession of all finite beings.


The purpose, as already noted, of the above sections II. to IV., as added in the second edition, is to afford ‘confirmation’ of the ideality of space and time. That being so, it is noticeable that Kant has omitted all reference to an argument embodied, for this same purpose, in § 13 of the Prolegomena. The matter is of sufficient importance to call for detailed consideration.[623]

As the argument of the Prolegomena is somewhat complicated, it is advisable to approach it in the light of its history in Kant’s earlier writings. It was to his teacher Martin Knutzen that Kant owed his first introduction to Newton’s cosmology; and from Knutzen he inherited the problem of reconciling Newton’s mechanical view of nature and absolute view of space with the orthodox Leibnizian tenets. In his first published work[624] Kant seeks to prove{162} that the very existence of space is due to gravitational force, and that its three-dimensional character is a consequence of the specific manner in which gravity acts. Substances, he teaches, are unextended. Space results from the connection and order established between them by the balancing of their attractive and repulsive forces. And as the law of gravity is merely contingent, other modes of interaction, and therefore other forms of space, with more than three dimensions, must be recognised as possible.

“A science of all these possible kinds of space would undoubtedly be the highest enterprise which a finite understanding could undertake in the field of geometry.”[625]

In the long interval between 1747 and 1768 Kant continued to hold to some such compromise, retaining Leibniz’s view that space is derivative and relative, and rejecting Newton’s view that it is prior to, and pre-conditions, all the bodies that exist in it. But in that latter year he published a pamphlet[626] in which, following in the steps of the mathematician, Euler,[627] he drew attention to certain facts which would seem quite conclusively to favour the Newtonian as against the Leibnizian interpretation of space. The three dimensions of space are primarily distinguishable by us only through the relation in which they stand to our body. By relation to the plane that is at right angles to our body we distinguish ‘above’ and ‘below’; and similarly through the other two planes we determine what is ‘right’ and ‘left,’ ‘in front’ and ‘behind.’ Through these distinctions we are enabled to define differences which cannot be expressed in any other manner. All species of hops—so Kant maintains—wind themselves around their supports from left to right, whereas all species of beans take the opposite direction. All snail shells, with some three exceptions, turn, in descending from their apex downwards, from left to right. This determinate direction of movement, natural to each species, like the difference in spatial configuration between a right and a left hand, or between a right hand and its reflection in a mirror, involves in all cases a reference of the given object to the wider space within which it falls, and ultimately to space as a whole. Only so can its determinate character be distinguished from its opposite counterpart. For as Kant points out, though the right and the left hand are counterparts, that is to say, objects which have a common{163} definition so long as the arrangement of the parts of each is determined in respect to its central line of reference, they are none the less inwardly incongruent, since the one can never be made to occupy the space of the other. As he adds in the Prolegomena, the glove of one hand cannot be used for the other hand. This inner incongruence compels us to distinguish them as different, and this difference is only determinable by location of each in a single absolute space that constrains everything within it to conform to the conditions which it prescribes. In three-dimensional space everything must have a right and a left side, and must therefore exhibit such inner differences as those just noted. Spatial determinations are not, as Leibniz teaches, subsequent to, and dependent upon, the relations of bodies to one another; it is the former that determine the latter.

“The reason why that which in the shape of a body exclusively concerns its relation to pure space can be apprehended by us only through its relation to other bodies, is that absolute space is not an object of any outer sensation, but a fundamental conception which makes all such differences possible.”[628]

Kant enforces his point by arguing that if the first portion of creation were a human hand, it would have to be either a right or a left hand. Also, a different act of creation would be demanded according as it was the one or the other. But if the hand alone existed, and there were no pre-existing space, there would be no inward difference in the relations of its parts, and nothing outside it to differentiate it. It would therefore be entirely indeterminate in nature, i.e. would suit either side of the body, which is impossible.

This adoption of the Newtonian view of space in 1768 was an important step forward in the development of Kant’s teaching, but could not, in view of the many metaphysical difficulties to which it leads, be permanently retained; and in the immediately following year—a year which, as he tells us,[629] “gave great light”—he achieved the final synthesis which enabled him to combine all that he felt to be essential in the opposing views. Though space is an absolute and preconditioning source of differences which are not conceptually resolvable, it is a merely subjective form of our sensibility.

Now it is significant that when Kant expounds this view in the Dissertation of 1770, the argument from incongruous counterparts is no longer employed to establish the absolute{164} and pre-conditioning character of space, but only to prove that it is a pure non-conceptual intuition.

“Which things in a given space lie towards one side, and which lie towards the other, cannot by any intellectual penetration be discursively described or reduced to intellectual marks. For in solids that are completely similar and equal, but incongruent, such as the right and the left hand (conceived solely in terms of their extension), or spherical triangles from two opposite hemispheres, there is a diversity which renders impossible the coincidence of their spatial boundaries. This holds true, even though they can be substituted for one another in all those respects which can be expressed in marks that are capable of being made intelligible to the mind through speech. It is therefore evident that the diversity, that is, the incongruity, can only be apprehended by some species of pure intuition.”[630]

There is no mention of this argument in the first edition of the Critique, and when it reappears in the Prolegomena it is interpreted in the light of an additional premiss, and is made to yield a very different conclusion from that drawn in the Dissertation, and a directly opposite conclusion from that drawn in 1768. Instead of being employed to establish either the intuitive character of space or its absolute existence, it is cited as evidence in proof of its subjectivity. As in 1768, it is spoken of as strange and paradoxical, and many of the previous illustrations are used. The paradox consists in the fact that bodies and spherical figures, conceptually considered, can be absolutely identical, and yet for intuition remain diverse. This paradox, Kant now maintains[631] in opposition to his 1768 argument, proves that such bodies and the space within which they fall are not independent existences. For were they things in themselves, they would be adequately cognisable through the pure understanding, and could not therefore conflict with its demands. Being conceptually identical, they would necessarily be congruent in every respect. But if space is merely the form of sensibility, the fact that in space the part is only possible through the whole will apply to everything in it, and so will generate a fundamental difference between conception and intuition.[632] Things in themselves are, as such, unconditioned, and cannot, therefore, be dependent upon anything beyond themselves. The objects of intuition, in order to be possible, must be merely ideal.{165}

Now the new premiss which differentiates this argument from that of 1768, and which brings Kant to so opposite a conclusion, is one which is entirely out of harmony with the teaching of the Critique. In this section of the Prolegomena Kant has unconsciously reverted to the dogmatic standpoint of the Dissertation, and is interpreting understanding in the illegitimate manner which he so explicitly denounces in the section on Amphiboly.

“The mistake ... lies in employing the understanding contrary to its vocation transcendentally [i.e. transcendently] and in making objects, i.e. possible intuitions, conform to concepts, not concepts to possible intuitions, on which alone their objective validity rests.”[633]

The question why no mention of this argument is made in the second edition of the Critique is therefore answered. Kant had meantime, in the interval between 1783 and 1787,[634] become aware of the inconsistency of the position. So far from being a paradox, this assumed conflict rests upon a false view of the function of the understanding.[635] The relevant facts may serve to confirm the view of space as an intuition in which the whole precedes the parts;[636] but they can afford no evidence either of its absoluteness or of its ideality. In 1768 they seem to Kant to prove its absoluteness, only because the other alternative has not yet occurred to him. In 1783 they seem to him to prove its ideality, only because he has not yet completely succeeded in emancipating his thinking from the dogmatic rationalism of the Dissertation.

As already noted,[637] Kant’s reason for here asserting that space is intuitive in nature, namely, that in it the parts are conditioned by the whole, is also his reason for elsewhere describing it as an Idea of Reason. The further implication of the argument of the Prolegomena, that in the noumenal sphere the whole is made possible only by its unconditioned parts, raises questions the discussion of which must be deferred. The problem recurs in the Dialectic in connection with Kant’s definition of the Idea of the unconditioned. In the Ideas of Reason Kant comes to recognise the existence of concepts which do not conform to the reflective type analysed by the traditional logic, and to perceive that these Ideas can yield{166} a deeper insight than any possible to the discursive understanding. The above rationalistic assumption must not, therefore, pass unchallenged. It may be that in the noumenal sphere all partial realities are conditioned by an unconditioned whole.


Concluding Paragraph.[638]—The wording of this paragraph is in keeping with the increased emphasis which in the Introduction to the second edition is given to the problem, how a priori synthetic judgments are possible. Kant characteristically fails to distinguish between the problems of pure and applied mathematics, with resulting inconsecutiveness in his argumentation.{167}





I. Concerning Logic in General.—This Introduction[639] which falls into four divisions, is extremely diffuse, and contributes little that is of more than merely architectonic value. It is a repetition of the last section of the general Introduction, and of the introductory paragraphs of the Aesthetic, but takes no account of the definitions given in either of those two places. It does not, therefore, seem likely that it could have been written in immediate sequence upon the Aesthetic. It is probably later than the main body of the Analytic.[640] In any case it is externally tacked on to it; as Adickes has noted,[641] it is completely ignored in the opening section of the Analytic.[642]

In treating of intuition in the first sentence, Kant seems to have in view only empirical intuition.[643] Yet he at once proceeds to state that intuition may be pure as well as empirical.[644] Also, in asserting that “pure intuition contains only the form under which something is intuited,” Kant would seem to be adopting the view that it does not yield its own manifold, a conclusion which he does not, however, himself draw.

In defining sensibility,[645] Kant again ignores pure intuition. Sensuous intuition, it is stated, is the mode in which we are {168}affected by objects.[646] Understanding, in turn, is defined only in its opposition to sensibility, in the ordinary meaning of that term. Understanding is the faculty which yields thought of the object to which sense-affection is due. It is “the power of thinking the object of sensuous intuition”; and acts, it is implied, in and through pure concepts which it supplies out of itself.

“Without sensibility objects would not be given to us [i.e. the impressions, in themselves merely subjective contents, through which alone independent objects can be revealed to us, would be wanting]; without understanding they would not be thought by us [i.e. they would be apprehended only in the form in which they are given, viz. as subjective modes of our sensibility].”

Kant has not yet developed the thesis which the central argument of the Analytic is directed to prove, namely, that save through the combination of intuition and conception no consciousness whatsoever is possible. In these paragraphs he still implies that though concepts without intuition are empty they are not meaningless, and that though intuitions without concepts are blind they are not empty.[647] Their union is necessary for genuine knowledge, but not for the existence of consciousness as such.

“It is just as necessary to make our concepts sensuous, i.e. to add to them their object in intuition, as to make our intuitions intelligible, i.e. to bring them under concepts.”

Kant’s final Critical teaching is very different from this. Concepts are not first given in their purity, nor is “their object” added in intuition. Only through concepts is apprehension of an object possible, and only in and through such apprehension do concepts come to consciousness. Nor are intuitions “made intelligible” by being “brought under concepts.” Only as thus conceptually interpreted can they exist for consciousness. The co-operation of concept and intuition is necessary for consciousness in any and every form, even the simplest and most indefinite. Consciousness of the subjective is possible only in and through consciousness of the objective, and vice versa. The dualistic separation of sensibility from understanding persists, however, even in Kant’s later utterances; and, as above stated,[648] to this sharp opposition are due both the strength and the weakness of Kant’s teaching. Intuition and conception must, he here insists, be carefully distinguished. Aesthetic is the “science of the rules of sensibility in general.” Logic is the “science of the rules of understanding in general.{169}

Kant’s classification of the various kinds of logic[649] may be exhibited as follows:


Adickes[650] criticises Kant’s classification as defective, owing to the omission of the intermediate concept ‘ordinary.’ Adickes therefore gives the following table:

transcendental ordinary
special general
pure applied

General logic is a logic of elements, i.e. of the absolutely necessary laws of thought, in abstraction from all differences in the objects dealt with, i.e. from all content, whether empirical or transcendental. It is a canon of the understanding in its general discursive or analytic employment. When it is pure, it takes no account of the empirical psychological conditions under which the understanding has to act. When it is developed as an applied logic, it proceeds to formulate rules for the employment of understanding under these subjective conditions. It is then neither canon, nor organon, but simply a catharticon of the ordinary understanding. Special logic is the organon of this or that science, i.e. of the rules governing correct thinking in regard to a certain class of objects. Only pure general logic is a pure doctrine of reason. It alone is absolutely independent of sensibility, of everything empirical, and therefore of psychology. Such pure logic is a body of demonstrative teaching, completely a priori. It stands to applied logic in the same relation as pure to applied ethics.

“Some logicians, indeed, affirm that logic presupposes psychological principles. But it is just as inappropriate to bring principles{170} of this kind into logic as to derive the science of morals from life. If we were to take the principles from psychology, that is, from observations on our understanding, we should merely see how thought takes place, and how it is affected by the manifold subjective hindrances and conditions; so that this would lead only to the knowledge of contingent laws. But in logic the question is not of contingent, but of necessary laws; not how we do think, but how we ought to think. The rules of logic, then, must not be derived from the contingent, but from the necessary use of the understanding which without any psychology a man finds in himself. In logic we do not want to know how the understanding is and thinks, and how it has hitherto proceeded in thinking, but how it ought to proceed in thinking. Its business is to teach us the correct use of reason, that is, the use which is consistent with itself.”[651]

By a canon Kant means a system of a priori principles for the correct employment of a certain faculty of knowledge.[652] By an organon Kant means instruction as to how knowledge may be extended, how new knowledge may be acquired. A canon formulates positive principles through the application of which a faculty can be directed and disciplined. A canon is therefore a discipline based on positive principles of correct use. The term discipline is, however, reserved by Kant[653] to signify a purely negative teaching, which seeks only to prevent error and to check the tendency to deviate from rules. When a faculty has no correct use (as, for instance, pure speculative reason), it is subject only to a discipline, not to a canon. A discipline is thus “a separate, negative code,” “a system of caution and self-examination.” It is further distinguished from a canon by its taking account of other than purely a priori conditions. It is related to a pure canon much as applied is related to general logic. As a canon supplies principles for the directing of a faculty, its distinction from an organon obviously cannot be made hard and fast. But here as elsewhere Kant, though rigorous and almost pedantic in the drawing of distinctions, is correspondingly careless in their application. He describes special logic as the organon of this or that science.[654] We should expect from the definition given in the preceding sentence that it would rather be viewed as a canon. In A 46 = B 63 Kant speaks of the Aesthetic as an organon.

II. Concerning Transcendental Logic.—It is with the distinction between general and transcendental logic that Kant is chiefly concerned. It is a distinction which he has himself{171} invented, and which is of fundamental importance for the purposes of the Critique. Transcendental logic is the new science which he seeks to expound in this second main division of the Doctrine of Elements. The distinction, from which all the differences between the two sciences follow, is that while general logic abstracts from all differences in the objects known, transcendental logic abstracts only from empirical content. On the supposition, not yet proved by Kant, but asserted in anticipation, that there exist pure a priori concepts which are valid of objects, there will exist a science distinct in nature and different in purpose from general logic. The two logics will agree in being a priori, but otherwise they will differ in all essential respects.

The reference in A 55 = B 79 to the forms of intuition is somewhat ambiguous. Kant might be taken as meaning that in transcendental logic abstraction is made not only from everything empirical but also from all intuition. That is not, however, Kant’s real view, or at least not his final view. In sections A 76-7 = B 102, A 130-1 = B 170, and A 135-6 = B 174-5, which are probably all of later origin, he states his position in the clearest terms. Transcendental logic, he there declares, differs from general logic in that it is not called upon to abstract from the pure a priori manifolds of intuition.[655] This involves, it may be noted, the recognition, so much more pronounced in the later developments of Kant’s Critical teaching, of space and time as not merely forms for the apprehension of sensuous manifolds but as themselves presenting to the mind independent manifolds of a priori nature.

As the term transcendental indicates, the new logic will have as its central problems the origin, scope, conditions and possibility of valid a priori knowledge of objects. None of these problems are treated in general logic, which deals only with the understanding itself. The question which it raises is, as Kant says in his Logic,[656] How can the understanding know itself? The question dealt with by transcendental logic we may formulate in a corresponding way: How can the understanding possess pure a priori knowledge of objects? It is a canon of pure understanding in so far as that faculty is capable of synthetic, objective knowledge a priori.[657] General logic involves, it is true, the idea of reference to objects,[658] but the possibility of such reference is not itself investigated. In general logic the understanding deals only with itself. It assumes indeed that all objects must conform to its laws, but this assumption plays no part in the science itself.{172}

A further point, not here dwelt upon by Kant, calls for notice, namely, that the activities of understanding dealt with by general logic are its merely discursive activities,—those of discrimination and comparison; whereas those dealt with by transcendental logic are the originative activities through which it produces a priori concepts from within itself, and through which it attains, independently of experience, to an a priori determination of objects. Otherwise stated, general logic deals only with analytic thinking, transcendental logic with the synthetic activities that are involved in the generation of the complex contents which form the subject matter of the analytic procedure.

III. Concerning the Division of General Logic into Analytic and Dialectic.[659]—The following passage from Kant’s Logic[660] forms an excellent and sufficient comment upon the first four paragraphs of this section:

“An important perfection of knowledge, nay, the essential and inseparable condition of all its perfection, is truth. Truth is said to consist in the agreement of knowledge with the object. According to this merely verbal definition, then, my knowledge, in order to be true, must agree with the object. Now I can only compare the object with my knowledge by this means, namely by having knowledge of it. My knowledge, then, is to be verified by itself, which is far from being sufficient for truth. For as the object is external to me, I can only judge whether my knowledge of the object agrees with my knowledge of the object. Such a circle in explanation was called by the ancients Diallelos. And, indeed, the logicians were accused of this fallacy by the sceptics, who remarked that this account of truth was as if a man before a judicial tribunal should make a statement, and appeal in support of it to a witness whom no one knows, but who defends his own credibility by saying that the man who had called him as a witness is an honourable man. The charge was certainly well-founded. The solution of the problem referred to is, however, absolutely impossible for any man.

“The question is in fact this: whether and how far there is a certain, universal, and practically applicable criterion of truth. For this is the meaning of the question, What is truth?...

“A universal material criterion of truth is not possible; the phrase is indeed self-contradictory. For being universal it would necessarily abstract from all distinction of objects, and yet being a material criterion, it must be concerned with just this distinction in order to be able to determine whether a cognition agrees with the very object to which it refers, and not merely with some object or other, by which nothing would be said. But material truth must consist in this agreement of a cognition with the definite object to which it refers. For a cognition which is true in reference to one object{173} may be false in reference to other objects. It is therefore absurd to demand a universal material criterion of truth, which is at once to abstract and not to abstract from all distinction of objects.

“But if we ask for a universal formal criterion of truth, it is very easy to decide that there may be such a criterion. For formal truth consists simply in the agreement of the cognition with itself when we abstract from all objects whatever, and from every distinction of objects. And hence the universal formal criteria of truth are nothing but universal logical marks of agreement of cognitions with themselves, or, what is the same thing, with the general laws of the understanding and the Reason. These formal universal criteria are certainly not sufficient for objective truth, but yet they are to be viewed as its conditio sine qua non. For before the question, whether the cognition agrees with the object, must come the question, whether it agrees with itself (as to form). And this is the business of logic.”[661]

The remaining paragraphs[662] of Section III. may similarly be compared with the following passage from an earlier section of Kant’s Logic:[663]

“Analytic discovers, by means of analysis, all the activities of reason which we exercise in thought. It is therefore an analytic of the form of understanding and of Reason, and is justly called the logic of truth, since it contains the necessary rules of all (formal) truth, without which truth our knowledge is untrue in itself, even apart from its objects. It is therefore nothing more than a canon for deciding on the formal correctness of our knowledge.

“Should we desire to use this merely theoretical and general doctrine as a practical art, that is, as an organon, it would become a dialectic, i.e. a logic of semblance (ars sophistica disputatoria), arising out of an abuse of the analytic, inasmuch as by the mere logical form there is contrived the semblance of true knowledge, the characters of which must, on the contrary, be derived from agreement with objects, and therefore from the content.

“In former times dialectic was studied with great diligence. This art presented false principles in the semblance of truth, and sought, in accordance with these, to maintain things in semblance. Amongst the Greeks the dialecticians were advocates and rhetoricians who could lead the populace wherever they chose, because the populace lets itself be deluded with semblance. Dialectic was therefore at that time the art of semblance. In logic, also, it was for a long time treated under the name of the art of disputation, and during that period all logic and philosophy was the cultivation by certain chatterboxes of the art of semblance. But nothing can be more unworthy of a philosopher than the cultivation of such an art. Dialectic in this form, therefore, must be altogether suppressed, and instead of it there{174} must be introduced into logic a critical examination of this semblance.

“We should then have two parts of logic: the analytic, which will treat of the formal criteria of truth, and the dialectic, which will contain the marks and rules by which we can know that something does not agree with the formal criteria of truth, although it seems to agree with them. Dialectic in this form would have its use as a cathartic of the understanding.”

Dialectic is thus interpreted in a merely negative sense. It is, Kant says, a catharticon. So far from being an organon, it is not even a canon. It is merely a discipline.[664] By this manner of defining dialectic Kant causes some confusion. It does not do justice to the scope and purpose of that section of the Critique to which it gives its name.[665]

IV. Concerning the Division of Transcendental Logic into Transcendental Analytic and Dialectic.—The term object[666] is used throughout this section in two quite distinct senses. In the second and third sentences it is employed in its wider meaning as equivalent to content or matter. In the fourth sentence it is used in the narrower and stricter sense, more proper to the term, namely, as meaning ‘thing.’ Again, in the fifth sentence content (Inhalt) would seem to be identified with object in the narrower sense, while in the sixth sentence matter (Materie, a synonym for content) appears to be identified with object in the wider sense. Transcendental Dialectic, in accordance with the above account of its logical correlate, is defined in a manner which does justice only to the negative side of its teaching. Its function is viewed as merely that of protecting the pure understanding against sophistical illusions.[667]


Division I


The chief point of this section[668] lies in its insistence that, as the Analytic is concerned only with the pure understanding, the a priori concepts with which it deals must form a unity or system. Understanding is viewed as a separate faculty,{175} and virtually hypostatised. As a separate faculty, it must, it is implied, be an independent unity, self-containing and complete. Its concepts are determined in number, constitution, and interrelation, by its inherent character. They originate independently of all differences in the material which they are employed to organise.



Introductory Paragraph.—Kant’s view of the understanding as a separate faculty is in evidence again in this paragraph.[669] The Analytic is a “dissection of the faculty of the understanding.” A priori concepts are to be sought nowhere but in the understanding itself, as their birthplace. There “they lie ready till at last, on the occasion of experience, they become developed.” But such statements fail to do justice to Kant’s real teaching. They would seem to reveal the persisting influence of the pre-Critical standpoint of the Dissertation.



That the understanding is “an absolute unity” is repeated. From this assertion, thus dogmatically made, without even an attempt at argument, Kant deduces the important conclusion that the pure concepts, originating from such a source, “must be connected with each other according to one concept or idea (Begriff oder Idee).” And he adds the equally unproved assertion:

“But such a connection supplies a rule by which we are enabled to assign its proper place to each pure concept of the understanding and by which we can determine in an a priori manner their systematic completeness. Otherwise we should be dependent in these matters on our own discretionary judgment or merely on chance.”


In the next section he sets himself to discover from an examination of analytic thinking what this rule or principle actually is, and in so doing he for the first time discloses, in any degree at all adequate, the real nature of the position which he is seeking to develop. He connects the required principle with the nature of the act of judging, considered as a function of unity.

Section I. The Logical Use of the Understanding.—This section,[670] viewed as introductory to the metaphysical deduction of the categories, is extremely unsatisfactory. It directs attention to the wrong points, and conceals rather than defines Kant’s real position. Its argumentation is also contorted and confused, and only by the most patient analysis can it be straightened out. The commentator has presented to him a twofold task from which there is no escape. He must render the argument consistent by such modification as will harmonise it with Kant’s later and more deliberate positions, and he must explain why Kant has presented it in this misleading manner.

The title of the section would seem to imply that only the discursive activities of understanding are to be dealt with. That is, indeed, in the main true. Confusion results, however, from the clashing of this avowed intention with the ultimate purpose in view of which the argument is propounded. Kant is seeking to prove that we can derive from the more accessible procedure of the discursive understanding a clue sufficient for determining those pre-logical activities which have to be postulated in terms of his new Copernican hypothesis. But though that is the real intention of this section, it has, unfortunately, not been explicitly recognised, and can be divined by the reader only after he has mastered the later portions of the Analytic. Kant’s argument has also the further defect that no sufficient statement is given either of the nature of the discursive concept or of its relation to judgment. These lacunae we must fill out as best we can from his utterances elsewhere. I shall first state Kant’s view of the distinction between discursive and synthetic thinking, and then examine his treatment of the nature of the concept and of its relation to judgment.

As already noted,[671] the distinction between transcendental and general logic marks for Kant all-important differences in the use of the understanding. In the one employment{177} the understanding, by creative synthetic activities, generates from the given manifold the complex objects of sense-experience. In so doing it interprets and organises the manifold through concepts which originate from within itself. By the other it discriminates and compares, and thereby derives from the content of sense-experience the generic concepts of the traditional logic. Now Kant would seem to argue in this section that if the difference in the origin of the concepts in those two cases be left out of account, and if we attend only to the quite general character of their respective activities, they will be found to agree in one fundamental feature, namely, that they express functions of unity. Each is based on the spontaneity of thought—on the spontaneity of synthetic interpretation on the one hand, of discrimination and comparison on the other. This feature common to the two types of activity can be further defined as being the unity of the act whereby a multiplicity is comprehended under a single representation. In the judgment “every metal is a body” the variety of metals is reduced to unity through the concept body. In an analogous manner the synthetic understanding organises a manifold of intuition through some such form of unity as that of substance and attribute. That is the category which underlies the above proposition, and which renders possible the specific unity of the total judgment. To quote the sentence with which in a later section Kant introduces his table of categories:

“The same understanding, and by the same operations by which in concepts, by means of analytic unity, it has produced the logical form of a judgment, introduces, by means of the synthetic unity of the manifold in intuition in general, a transcendental element into its representations....”[672]

Now Kant’s exposition is extremely misleading. As his later utterances show, his real argument is by no means that which is here given. We shall have occasion to observe that Kant is unable to prove, and does not ultimately profess to prove, that it is “the same understanding,” and still less that it is “the same operations,” which are exercised in discursive and in creative thinking. But this is a criticism which it would be premature to introduce at this stage. We must proceed to it by way of preliminary analysis of the above exposition. Kant’s argument does not rest upon any such analogy as that just drawn, between the concepts formed by consciously comparing contents and the concepts which originate from within the understanding itself. Both, it is{178} true, are functions of unity, but otherwise there is, according to Kant’s own teaching, not the least resemblance between them. A generic or abstract concept expresses common qualities found in each of a number of complex contents. It is itself a content. A category, on the other hand, is always a function of unity whereby contents are interpreted. It is not a content, but a form for the organisation of content.[673] It can gain expression only in the total act of judging, not in any one element such as the discursive concept. But though the analogy drawn by Kant thus breaks down, his argument is continued in a new and very different form. It is no longer made to rest on any supposed resemblance between discursive and creative thinking, regarded as co-ordinate and independent activities. It now consists in the proof that the former presupposes and is conditioned by the latter. Through study of the understanding in its more accessible discursive procedure, we may hope to discover the synthetic forms according to which it has proceeded in its pre-logical activities. When we determine the various forms of analytic judgment, the categories which are involved in synthetic thinking reveal themselves to consciousness.

Thus in spite of Kant’s insistence upon the conceptual predicate, and upon the unity to which it gives expression, immediately he proceeds to the deduction of the categories, the emphasis is shifted to the unity which underlies the judgment as a whole. What constitutes such propositions as “all bodies are divisible,” “every metal is a body,” a unique and separate type of judgment is not the character of the predicate, but the category of substance and attribute whereby the predicate is related to the subject. To that category they owe their specific form; and it is a function of unity for which the discursive understanding can never account. As Kant states in the Prolegomena, if genuine judgments, that is, judgments that are “objectively valid,” are analysed,

“ will be found that they never consist of mere intuitions connected only (as is commonly believed) by comparison in a judgment. They would be impossible were not a pure concept of the understanding{179} superadded to the concepts abstracted from intuition. The abstract concepts are subsumed under a pure concept, and in this manner only can they be connected in an objectively valid judgment.”[674]

Thus the analogy between discursive and a priori concepts is no sooner drawn than it is set aside as irrelevant. Though generic concepts rest upon functions of unity, and though (as we shall see immediately) they exist only as factors in the total act of judging, there is otherwise not the least resemblance between them and the categories.[675] The clue to the categories is not to be found in the inherent characteristics of analytic thinking, or of its specific products (namely, concepts), but solely in what, after all abstraction, it must still retain from the products which synthetic thinking creates. Each type of analytic judgment will be found on examination to involve some specific function whereby the conceptual factors are related to, and unified with, the other elements in the judgment. This function of unity is in each case an a priori category of the understanding. That is the thesis which underlies the concluding sentence of this section.

“The functions of the understanding [i.e. the a priori concepts of understanding] can be discovered in their completeness, if it is possible to state exhaustively the functions of unity [i.e. the forms of relation] in judgments.”

The adoption of such a position involves, it may be noted, the giving up of the assertion, which is so emphatically made in the passage above quoted, that it is by the same activities that the understanding discursively forms abstract concepts and creatively organises the manifold of sense. That is in no respect true. There is no real identity—there is not even analogy—between the processes of comparison and abstraction on the one hand and those of synthetic interpretation on the other. The former are merely reflective: the latter are genuinely creative. Discursive activities are conscious processes, and are under our control: the synthetic processes, are non-conscious; only their finished products appear within the conscious field. This, however, is to anticipate a conclusion which was among the last to be realised by Kant himself, namely that there is no proof that these two types of activity are ascribable to one and the same source. The synthetic activities—as he himself finally came to hold—are due to a faculty of imagination.{180}

“Synthesis in general ... is the mere result of the power of imagination, a blind but indispensable function of the soul, without which we should have no knowledge whatsoever, but of which we are scarcely ever conscious.”[676]

This sentence occurs in a passage which is undoubtedly a later interpolation.[677] The “scarcely ever” (selten nur einmal) indicates Kant’s lingering reluctance to recognise this fundamental fact, destructive of so much in his earlier views, even though it completes and reinforces his chief ultimate conclusions. With this admission Kant also gives up his sole remaining ground for the contention that there must be a complete parallelism between discursive and creative thinking. If they arise from such different sources, we have no right to assume, without specific proof, that they must coincide in the forms of their activity. This is a point to which we shall return in discussing Kant’s formulation of the principle which is supposed to guarantee the completeness of the table of categories.

This unavowed change in point of view is the main cause of confusion in this section. Its other defects are chiefly those of omission. Kant fails to develop in sufficient detail his view of the nature of the discursive concept, or to make sufficiently clear the grounds for his assertion that conception as an activity of the understanding is identical with judgment. To take the former point first. Kant’s mode of viewing the discursive concept finds expression in the following passage in the Introduction to his Logic:[678]

“Human knowledge is on the side of the understanding discursive; that is, it takes place by means of ideas which make what is common to many things the ground of knowledge: and hence by means of attributes as such. We therefore cognise things only by means of attributes. An attribute is that in a thing which constitutes part of our cognition of it; or, what is the same, a partial conception so far as it is considered as a ground of cognition of the whole conception. All our concepts, therefore, are attributes, and all thought is nothing but conception by means of attributes.

The limitations of Kant’s view of the concept could hardly find more definite expression. The only type of judgment which receives recognition is the categorical, interpreted in the traditional manner.[679]

“To compare something as a mark with a thing, is called ‘to judge.’ The thing itself is the subject, the mark [or attribute] is the {181} predicate. The comparison is expressed by the word ‘is,’ ... which when used without qualification indicates that the predicate is a mark [or attribute] of the subject, but when combined with the sign of negation states that the predicate is a mark opposed to the subject.”[680]

Kant’s view of analytic thinking is entirely dominated by the substance-attribute teaching of the traditional logic. A concept must, in its connotation, be an abstracted attribute, and in its denotation represent a class. Relational thinking, and the concepts of relation, are ignored. Thus, in the Aesthetic, as we have already noted,[681] Kant maintains that since space and time are not generic class concepts they must be intuitions. This argument, honestly employed by Kant, shows how completely unconscious he was of the revolutionary consequences of his new standpoint. Even in the very act of insisting upon the relational character of the categories, he still continues to speak of the concept as if it must necessarily conform to the generic type. In this, as in so many other respects, transcendental logic is not, as he would profess, supplementary to general logic; it is its tacit recantation. Modern logic, as developed by Lotze, Sigwart, Bradley, and Bosanquet, is, in large part, the recasting of general logic in terms of the results reached by Kant’s transcendental enquiries. Meantime, sufficient has been said to indicate the strangely limited character of Kant’s doctrine of the logical concept.

But on one fundamental point Kant breaks entirely free from the traditional logic. The following passage occurs in the above-quoted pamphlet on The Mistaken Subtlety of the Four Syllogistic Figures:

“It is clear that in the ordinary treatment of logic there is a serious error in that distinct and complete concepts are treated before judgments and ratiocinations, although the former are only possible by means of the latter.” “I say, then, first, that a distinct concept is possible only by means of a judgment, a complete concept only by means of a ratiocination. In fact, in order that a concept should be distinct, I must clearly recognise something as an attribute of a thing, and this is a judgment. In order to have a distinct concept of body, I clearly represent to myself impenetrability as an attribute of it. Now this representation is nothing but the thought, ‘a body is impenetrable.’ Here it is to be observed that this judgment is not the distinct concept itself, but is the act by which it is realised; for the idea of the thing which arises after this act is distinct. It is easy to show that a complete concept is only possible by means of a ratiocination: for this it is sufficient to refer to the first section{182} of this essay. We might say, therefore, that a distinct concept is one which is made clear by a judgment, and a complete concept one which is made distinct by a ratiocination. If the completeness is of the first degree, the ratiocination is simple; if of the second or third degree, it is only possible by means of a chain of reasoning which the understanding abridges in the manner of a sorites.... Secondly, as it is quite evident that the completeness of a concept and its distinctness do not require different faculties of the mind (since the same capacity which recognises something immediately as an attribute in a thing is also employed to recognise in this attribute another attribute, and thus to conceive the thing by means of a remote attribute), so also it is evident that understanding and reason, that is, the power of cognising distinctly and the power of forming ratiocinations, are not different faculties. Both consist in the power of judging, but when we judge mediately we reason.”[682]

In the section before us this same standpoint is maintained, but is expressed in a much less satisfactory manner. Concepts are no longer spoken of as complete judgments. In the above passages Kant always speaks of the concept as the subject of the proposition; it is now treated only as a predicate.[683] This difference is significant. The concept as subject can represent the judgment as a whole (or at least it does so from the traditional standpoint to which Kant holds); the concept as predicate is merely one element, even though it be a unifying element, in the total act of judging. This falling away from his own maturer standpoint would seem to be due to Kant’s lack of clearness as to the nature of the analogy which he is here drawing between analytic and synthetic thinking. It is connected with his mistaken, and merely temporary, comparison of a priori with discursive concepts. His position in 1762 alone harmonises with his essential teaching. Now, as then, he is prepared to view judgment as the sole ultimate activity of the understanding, and therefore to define understanding as the faculty of judging.

But the new Critical standpoint compels Kant to reinterpret this definition in a manner which involves a still more radical transformation of the traditional doctrine. The categories constitute a unique type of concept, and condition the processes of discursive thought. They are embodied in the complex contents from which analytic thinking starts; and however far the processes of discursive comparison and abstraction be carried, one or other of these categories must still persist, determining the form which the analytic judgment {183}is to take. The categorical judgment can formulate itself only by means of the a priori concept of subject and attribute, the hypothetical only by means of the pure concept of ground and consequence, and so with the others. And there are in consequence just as many categories as there are forms of the analytic judgment. This is how the principle of the metaphysical deduction must be interpreted when the later and deeper results of the transcendental deduction are properly taken into account. In deducing the forms of the understanding from the modes of discursive judgment Kant is virtually maintaining that analytic judgment involves the same problems as does judgment of the synthetic type. The categories can be derived from the forms of discursive judgment only because they are the conditions in and through which it becomes possible.

But though Kant, both here and in the central portions of the Analytic, seems to be on the very brink of this conclusion, it is never explicitly drawn. As we shall see,[684] it would have involved the further admission that there is no absolute guarantee of the completeness of the table of categories, and no satisfactory method of determining their interrelations. To the very last general logic is isolated from transcendental logic. The Critical enquiry is formulated as if it concerned only such judgments as are explicitly synthetic. The principle of the metaphysical deduction is not, therefore, stated by Kant himself in the above manner; and we have still to decide the difficult question as to what the principle employed by Kant in the deduction actually is.

Kant makes a twofold demand upon the principle. It must enable us to discover the categories, and it must also in so doing enable us to view them as together forming a systematic whole, and so as having their completeness guaranteed by other than merely empirical considerations. The principle is stated sometimes in a broader and sometimes in a more specific form; for on this point also Kant speaks with no very certain voice.[685] The broader formulation of the principle is that all acts of understanding are judgments, and that therefore the possible ultimate a priori forms of understanding are identical with the possible ultimate forms of the judgment.[686] The more specific and correct formulation is that to every form of analytic judgment there corresponds a pure concept of understanding. The first statement of the {184}principle is obviously inadequate. It merely reformulates the problem as being a problem not of conception but of judgment. If a principle is required to guarantee the completeness of our list of a priori concepts, it will equally be required to guarantee the completeness of our list of judgments. Even if the above principle be more explicitly formulated, as in the Prolegomena,[687] where judging is defined as the act of understanding which comprises all its other acts, it will not enable us to guarantee the completeness of any list of the forms of judgment or to determine their systematic interrelation. We are therefore thrown back upon the second view. This, however, only brings us face to face with the further question, what principle guarantees the completeness of the table of analytic judgments. And to that query Kant has absolutely no answer. The reader’s questionings break vainly upon his invincible belief in the adequacy and finality of the classification yielded by the traditional logic.

The fons et origo of all the confusions and obscurities of this section are thus traceable to Kant’s attitude towards formal logic. He might criticise it for ignoring the interdependence of conception, judgment, and reasoning; he might reject the second, third, and fourth syllogistic figures; and he might even admit that its classification of the forms of judgment is not as explicit as might be desired; but however many provisos he made and defects he acknowledged, they were to him merely minor matters, and he accepted its teaching as complete and final. This unwavering faith in the fundamental distinctions of the traditional logic was indeed, as we shall have constant occasion to observe, an ever present influence in determining alike the general framework and much of the detail of Kant’s Critical teaching. The defects of the traditional logic were very clearly indicated in his own transcendental logic. He showed that synthetic thinking is fundamental; that by its distinctions the forms and activities of analytic thought are predetermined; that judgment in its various forms can be understood only by a regress upon the synthetic concepts to which these forms are due; that notions are not merely of the generic type, but that there are also categories of relation. None the less, to the very last, Kant persisted in regarding general logic as a separate discipline, and as quite adequate in its current form. He continued to ignore the fact that the analytic judgment, no less than the synthetic judgment, demands a transcendental justification.

The resulting situation is strangely perverse. In the very act of revolutionising the traditional logic, Kant relies upon its prestige and upon the assumed finality of its results to{185} make good the shortcomings of the logic which is to displace it. By Kant’s own admission transcendental logic is incapable of guaranteeing that completeness upon which, throughout the whole Critique, so great an emphasis is laid. General logic is allowed an independent status, sufficient to justify its authority being appealed to; and the principle which is supposed to guarantee the completeness of the table of categories is so formulated as to contain no suggestion of the dependence of discursive upon synthetic thinking. Formal logic, Kant would seem to hold, can supply a criterion for the classification of the ultimate forms of judgment just because its task is relatively simple, and is independent of all epistemological views as to the nature, scope, and conditions of the thought process. Since formal logic is a completed and perfectly a priori science, which has stood the test of 2000 years, and remains practically unchanged to the present day, its results can be accepted as final, and can be employed without question in all further enquiries. Analytic thinking is scientifically treated in general logic; the Critique is concerned only with the possibility and conditions of synthetic judgment. The table of analytic judgments therefore supplies a complete and absolutely guaranteed list of the possible categories of the understanding. But the perverseness of this whole procedure is shown by the manner in which, as we shall find, Kant recasts, extends, or alters, to suit his own purposes, the actual teaching of the traditional logic.

As noted above,[688] the asserted parallelism of analytic and synthetic judgment rests upon the further assumption that discursive thinking and synthetic interpretation are the outcome of one and the same faculty of understanding. It is implied, in accordance with the attitude of the pre-Critical Dissertation, that understanding, viewed as the faculty to which all thought processes are due, has certain laws in accordance with which it necessarily acts in all its operations, and that these must therefore be discoverable from analytic no less than from synthetic thinking. The mingling of truth and falsity in this assumption has already been indicated. Such truth as it contains is due to the fact that analytic thinking is not co-ordinate with, but is dependent upon, and determined by, the forms of synthetic thinking. Its falsity consists in its ignoring of what thus gives it partial truth. The results of the transcendental deduction call for a complete recasting of the entire argument of the metaphysical deduction. And when this is done, there is no longer any ground for the contention that the number of the categories is determinable{186} on a priori grounds. On Kant’s own fundamental doctrine of the synthetic, and therefore merely de facto, character of all a priori principles, the necessity of the categories is only demonstrable by reference to the contingent fact of actual experience. The possible conceptual forms are relative to actual and ultimate differences in the contingent sensuous material; and being thus relative, they cannot possibly be systematised on purely a priori grounds. This Kant has himself admitted in a passage added in the second edition,[689] though apparently without full consciousness of the important consequences which must follow.

“This peculiarity of our understanding that it can produce a priori unity of apperception solely by means of the categories, and only by such and so many, is as little capable of further explanation as why we have just these and no other functions of judgment, or why space and time are the only forms of our possible intuition.”


The character of the metaphysical deduction will be placed in a clearer light if we briefly trace the stages, so far as they can be reconstructed, through which it passed in Kant’s mind. We may start from the Dissertation of 1770. Kant there modifies his earlier Wolffian standpoint, developing it, probably under the direct influence of the recently published Nouveaux Essais, on more genuinely Leibnizian lines.

“The use of the intellect ... is twofold. By the one use concepts, both of things and of relations, are themselves given. This is the real use. By the other use concepts, whencesoever given, are merely subordinated to each other, the lower to the higher (the common attributes), and compared with one another according to the principle of contradiction. This is called the logical use.... Empirical concepts, therefore, do not become intellectual in the real sense by reduction to greater universality, and do not pass beyond the type of sensuous cognition. However high the abstraction be carried, they must always remain sensuous. But in dealing with things strictly intellectual, in regard to which the use of the intellect is real, intellectual concepts (of objects as well as of relations), are given by the very nature of the intellect. They are not abstracted from any use of the senses, and do not contain any form of sensuous knowledge as such. We must here note the extreme ambiguity of the word abstract.... An intellectual concept abstracts from everything sensuous; {187}it is not abstracted from things sensuous. It would perhaps be more correctly named abstracting than abstract. It is therefore preferable to call the intellectual concepts pure ideas, and those which are given only empirically abstract ideas.”[690] “I fear, however, that Wolff, by this distinction between the sensuous and the intellectual, which for him is merely logical, has checked, perhaps wholly (to the great detriment of philosophy), that noblest enterprise of antiquity, the investigation of the nature of phenomena and noumena, turning men’s minds from such enquiries to what are very frequently only logical subtleties. Philosophy, in so far as it contains the first principles of the use of the pure intellect, is metaphysics.... As empirical principles are not to be found in metaphysics, the concepts to be met with in it are not to be sought in the senses but in the very nature of the pure intellect. They are not connate concepts, but are abstracted from laws inherent in the mind (legibus menti insitis), and are therefore acquired. Such are the concepts of possibility, existence, necessity, substance, cause, etc. with their opposites or correlates. They never enter as parts into any sensuous representation, and therefore cannot in any fashion be abstracted from such representations.”[691]

The etcetera, with which in that last passage Kant concludes his list of pure intellectual concepts, indicates a problem that must very soon have made itself felt. That it did so, appears from his letter to Herz (February 21, 1772). He there informs his correspondent, that, in developing his Transcendentalphilosophie (the first occurrence of that title in Kant’s writings), he has

“...sought to reduce all concepts of completely pure reason to a fixed number of categories [this term also appearing for the first time], not in the manner of Aristotle, who in his ten predicaments merely set them side by side in a sort of order, just as he might happen upon them, but as they distribute themselves of themselves according to some few principles of the understanding.”[692]

Though in this same letter Kant professes to have solved his problems, and to be in a position to publish his Critique of Pure Reason (this title is already employed) “within some three months,” the phrase “some few principles” clearly shows that he has not yet developed the teaching embodied in the metaphysical deduction. For its keynote is insistence upon the necessity of a single principle, sufficient to reduce them not merely to classes but to system. The difficulty of discovering such a principle must have been one of the causes which delayed completion of the Critique. The only data at our disposal for reconstructing the various stages through which Kant’s views may have passed in the period between{188} February 1772 and 1781 are the Reflexionen, but they are sufficiently ample to allow of our doing so with considerable definiteness.[693]

In the Dissertation Kant had traced the concepts of space and time, no less than the concepts of understanding, to mental activities.

“Both concepts [space and time] are undoubtedly acquired. They are not, however, abstracted from the sensing of objects (for sensation gives the matter, not the form of human cognition). As immutable types they are intuitively apprehended from the activity whereby the mind co-ordinates its sensuous data in accordance with perpetual laws.”[694]

Now the Dissertation is quite vague as to how the “mind” (animus), active in accordance with laws generative of the intuitions space and time, differs from “understanding” (intellectus), active in accordance with laws generative of pure concepts. Kant’s reasons, apart from the intuitive character of space and time, for contrasting the former with the latter, as the sensuous with the intellectual, were the existence of the antinomies and his belief that through pure concepts the absolutely real can be known. When, however, that belief was questioned by him, and he had come to regard the categories as no less subjective than the intuitional forms, the antinomies ceased to afford any ground for thus distinguishing between them. The intuitional nature of space and time, while certainly peculiar to them, is in itself no proof that they belong to the sensuous side of the mind.[695]

A difficulty which immediately faced Kant, from the new Critical standpoint, was that of distinguishing between space and time, on the one hand, and the categories on the other. This is borne out by the Reflexionen and by the following passage in the Prolegomena.[696]

“Only after long reflection, expended in the investigation of the pure non-empirical elements of human knowledge, did I at last succeed in distinguishing and separating with certainty the pure elementary concepts of sensibility (space and time) from those of the understanding.”

The first stage in the development of the metaphysical{189} deduction would seem to have consisted in the attempt to view the categories as acquired by reflection upon the activities of the understanding in “comparing, combining, or separating”;[697] and among the notiones rationales, notiones intellectus puri, thus gained, the idea of space is specially noted. The following list is also given:

“The concepts of existence (reality), possibility, necessity, ground, unity and plurality, parts, all, none, composite and simple, space, time, change, motion, substance and accident, power and action, and everything that belongs to ontology proper.”[698]

In Reflexionen, ii. 507 and 509, the fundamental feature of such rational concepts is found in their relational character. They all agree in being concepts of form.[699]

Quite early, however, Kant seems to have developed the view, which has created so many more difficulties than it resolves, that space and time are given to consciousness through outer and inner sense. Though still frequently spoken of as concepts, they are definitely referred to the receptive, non-spontaneous, side of the mind. This is at once a return to the Dissertation standpoint, and a decided modification of its teaching. It holds to the point of view of the Dissertation in so far as it regards them as sensuous, and departs from it in tracing them to receptivity.[700]

The passage quoted from the letter of 1772 to Herz may perhaps be connected with the stage revealed in the Reflexionen already cited. “Comparing, combining, and separating” may be the “some few principles of the understanding” there referred to. That, however, is doubtful, for the next stage in the development likewise resulted in a threefold division. This second stage finds varied expression in Reflexionen, ii. 483, 522, 528, 556-63. These, in so far as they agree, distinguish three classes of categories—of thesis, of analysis, and of synthesis. The first covers the categories of quality and modality, the second those of quantity, the third those of relation.

Reflexionen, ii. 528 is as follows:

[Thesis = ]“The metaphysical concepts are, first, absolute: possibility and existence; secondly, relative:
 (a) Unity and plurality: omnitudo and particularitas.
[Analysis = ](b) Limits: the first, the last: infinitum, finitum.
    [Anticipates the later category of limitation.] {190}
 (c) Connection: co-ordination: whole and part
[Synthesis = ]     [anticipates the later category of reciprocity],
simple and compound; subordination:
         (1) Subject and predicate.
         (2) Ground and consequence.

This, and the connected Reflexionen enumerated above, are of interest as proving that Kant’s table of categories was in all essentials complete before the idea had occurred to him of further systematising it or of guaranteeing its completeness by reference to the logical classification of the forms of judgment. They also justify us in the belief that when Kant set himself to discover such a unifying principle the above list of categories and the existing logical classifications must have mutually influenced one another, each undergoing such modification as seemed necessary to render the parallelism complete. This, as we shall find, is what actually happened. The logical table, for instance, induced Kant to distinguish the categories of quality from those of modality, while numerous changes were made in the logical table itself in order that it might yield the categories required.

But the most important alteration, the introduction of the threefold division of each sub-heading, is not thus explicable, as exclusively due to one or other of the two factors. The adoption of this threefold arrangement in place of the dichotomous divisions of the logical classification and of the haphazard enumerations of Kant’s own previous lists, seems to be due to the twofold circumstance that he had already distinguished three categories of synthesis or relation (always the most important for Kant), and that this sufficiently harmonised with the logical distinction between categorical, hypothetical, and disjunctive judgments. He then sought to modify the logical divisions by addition in each case of a third, and finding that this helped him to obtain the categories required, the threefold division became for him (as it remained for Hegel) an almost mystical dogma of transcendental philosophy.[701] In so far as it involved recognition that the hard and fast opposites of the traditional logic (such as the universal and the particular, the affirmative and the negative) are really aspects inseparably involved in every judgment and in all existence, it constituted an advance in the direction both of a deeper rationalism and of a more {191}genuine empiricism. But in so far as it was due to the desire to guarantee completeness on a priori grounds, and so was inspired by a persistent overestimate of our a priori powers, it has been decidedly harmful. Much of the useless “architectonic” of the Critique is due to this scholastic prejudice.

This fundamental alteration in the table of logical judgments is introduced with the naive assertion that “varieties of thought in judgments,” unimportant in general logic, “may be of importance in the field of its pure a priori knowledge.” In the Critique of Judgment[702] we find the following passage:

“It has been made a difficulty that my divisions in pure philosophy have almost always been threefold. But this lies in the nature of the case. If an a priori division is to be made, it must be either analytic, according to the principle of contradiction, and then it is always twofold (quodlibet ens est aut A aut non A); or else synthetic. And if in this latter case it is derived from a priori concepts (not as in mathematics from the a priori intuition corresponding to the concept) the division must necessarily be a trichotomy. For according to what is requisite for synthetic unity in general, there must be (1) a condition, (2) a conditioned, and (3) the concept which arises from the union of these two.”

The last stage, as expressed in the Critique, was, as we have already noted, merely an application of his earlier position that all thinking is judging. This appreciation of the inseparable connection of the categories with the act of judging is sound in principle, and is pregnant with many of the most valuable results of the Critical teaching. But these fruitful consequences follow only upon the lines developed in the transcendental deduction. They are bound up with Kant’s fundamental Copernican discovery that the categories are forms of synthesis, and accordingly express functions or relations. The categories can no longer be viewed, in the manner of the Dissertation,[703] as yielding concepts of objects. The view of the concept which we find in the Dissertation is, indeed, applied in the Critique to space and time—they are taken as in themselves intuitions, not as merely forms of intuition—but the categories are recognised as being of an altogether relational character. Though a priori, they are not, in and by themselves, complete objects of consciousness, and accordingly can reveal no object. They are functions, not contents. That, however, is to anticipate. We must first discharge, as briefly as possible, the ungrateful task of dwelling further upon the laboured, arbitrary, and self-contradictory character{192} of the detailed working out of the metaphysical deduction. The deduction is given in Sections II. and III.

Section II. The Logical Function of the Understanding in Judgment.[704]—Kant’s introductory statement may here be noted. If, he says, we leave out of consideration the content of any judgment, and attend only to the mere form, we “find” that the function of thought in a judgment “can” be brought under four heads, each with three subdivisions. But Kant himself, in this same section, recognises in the frankest and most explicit manner, that the necessary distinctions are only to be obtained by taking account of the matter as well as of the form of judgments. And even after this contradiction is discounted, the term “find” may be allowed as legitimate only if the word “can” is correspondingly emphasised. The distinctions were not derived from any existing logic. They were reached only by the freest possible handling of the classifications currently employed. Examination of the table of judgments, and comparison of it with the table of categories, supply conclusive evidence that the former has been rearranged, in highly artificial fashion, so as to yield a more or less predetermined list of required categories.

1. Quantity.—Kant here frankly departs from the classification of judgments followed in formal logic; and the reason which he gives for so doing is in direct contradiction to his demand that only the form of judgment must be taken into account. The “quantity of knowledge” here referred to is determinable, not from the form, but only from the content of the judgment. Also, the statement that the singular judgment stands to the universal as unity to infinity (Unendlichkeit) is decidedly open to question. The universal is itself a form of unity, as Kant virtually admits in deriving, as he does, the category of unity from the universal judgment.

2. Quality.—Kant makes a similar modification in the logical treatment of quality, by distinguishing between affirmative and infinite judgments. The proposition, A is not-B, is to be viewed as neither affirmative nor negative. As the content of the predicate includes the infinite number of things that are not-B, the judgment is infinite. Kant, in a very artificial and somewhat arbitrary manner, contrives to define it as limitative in character, and so as sharing simultaneously in the nature both of affirmation and of negation. The way is thus prepared for the “discovery” of the category of limitation.

3. Relation.—Wolff, Baumgarten, Meier, Baumeister,{193} Reimarus, and Lambert, with very minor differences, agree in the following division:[705]

Judgments–Simple = Categorical
Complex–Copulative (i.e. categorical with more than one subject or more than one predicate).

Kant omits the copulative judgment, and by ignoring the distinction between simple and complex judgments (which in Reimarus, and also less definitely in Wolff, is connected with the distinction between conditional and unconditional judgments) contrives to bring the remaining three types of judgment under the new heading of “relation.” They had never before been thus co-ordinated, and had never before been subsumed under this particular title. It is by no means clear why such distinctions as those between simple and complex, conditioned and unconditioned, should be ignored, and why the copulative judgment should not be recognised as well as the hypothetical. Kant’s criterion of importance and unimportance in the distinctions employed by the logicians of his day was wholly personal to himself; and, though hard to define, was certainly not dictated by any logic that is traceable to Aristotelian sources. His exposition is throughout controlled by foreknowledge of the particular categories which he desires to “discover.”

4. Modality.—Neither Wolff nor Reimarus gives any account of modality.[706] Baumgarten classifies judgments as pure or modal (existing in four forms, necessity, contingency, possibility, impossibility). Baumeister and Thomasius also recognise four forms of modality. Meier distinguishes between pure judgment (judicium purum) and impure judgment (judicium modale, modificatum, complexum qua copula), but does not classify the forms of modality. Lambert alone[707] classifies judgments as “possible, actual (wirklich), necessary, and their opposite.” But when Kant adopts this threefold division, the inclusion of actuality renders the general title “modality” inapplicable in its traditional sense. The expression of actuality in the assertoric judgment involves no adverbial modification of the predicate. Also, in its “affirmative” and “categorical” forms it has already been made to yield two other categories.{194}

Kant speaks of the problematic, the assertoric, and the apodictic forms of judgment as representing the stages through which knowledge passes in the process of its development.

“These three functions of modality are so many momenta of thought in general.”

This statement has been eulogised by Caird,[708] as being an anticipation of the Hegelian dialectic. As a matter of fact, Kant’s remark is irrelevant and misleading. The advance from consciousness of the problematic, through determination of it as actual to its explanation as necessary, represents only a psychological order in the mind of the individual. Logically, knowledge of the possible rests on and implies prior knowledge of the actual and of the necessities that constitute the actual.[709]

Section III.[710] The Categories or Pure Concepts of the Understanding.—The first three pages of this section, beginning “General logic abstracts,” and concluding with the word “rest on the understanding,” would seem to be a later interpolation. Embodying, as they do, some of the fundamental ideas of the transcendental deduction, they express Kant’s final method of distinguishing between general and transcendental logic. But they are none the less out of harmony with the other sections of the metaphysical deduction. They are of the nature of an after-thought, even though that afterthought represents a more mature and adequate standpoint. In A 55-7, where Kant defines the distinction between general and transcendental logic, the latter is formulated in entire independence of all reference to pure intuition.[711] Kant, indeed, argues[712] that just as there are both pure and empirical intuitions, so there are both pure and empirical concepts. But there is no indication that he has yet realised the close interdependence of the two types of a priori elements. Even when he proceeds in A 62 to remark that the empirical employment of pure concepts is conditioned by the fact that objects are given in intuition, no special reference is made to “the manifold of pure a priori intuition.” Now, however, Kant emphasises, as the fundamental characteristic of transcendental logic, its possession of a pure manifold through reference to which its pure concepts gain meaning. Thus not only does transcendental logic not abstract from the pure a priori concepts, it likewise possesses an a priori material.[713] It is in this twofold manner that it is now regarded as differing from formal logic.

The accounts given of the metaphysical deduction by{195} Cohen,[714] Caird,[715] Riehl,[716] and Watson[717] are vitiated by failure to remark that this latter standpoint is a late development, and is out of keeping with the rest of the deduction. Riehl’s exposition has, however, the merit of comparative consistency. He explicitly recognises the important consequence which at once follows from acceptance of this later view, namely, that it is by their implying space and time that the categories differ from the notions which determine the forms of judgment; in other words, that the categories are actualised only as schemata. The category of substance, for instance, differs from the merely logical notion of a propositional subject, in being the concept of that which is always a subject, and never a predicate; and such a conception has specific meaning for us only as the permanent in time. Logical subjects and predicates, quantitative relations apart, are interchangeable. The relation between them is the analytic relation of identity. The concept of subject, on the other hand, transcendentally viewed, that is, as a category, is the apprehension of what is permanent, in synthetic distinction from, and relation to, its changing attributes. In other words, the transcendental distinction between substance and accidents is substituted for that of subject and predicate. Similarly the logical relation of ground and consequence, conceived as expressive of logical identity, gives way to the synthetic temporal relation of cause and effect. And so with all the other pure forms. As categories, they are schemata. Kant has virtually recognised this by the names which he gives to the categories of relation. But the proper recognition of the necessary interdependence of the intuitional and conceptual forms came too late to prevent him from distinguishing between categories and schemata, and so from creating for himself the artificial difficulties of the section on schematism.

In A 82 Kant states that he intentionally omits definitions of the categories. He had good reason for so doing. The attempt would have landed him in manifold difficulties, since his views were not yet sufficiently ripe to allow of his perceiving the way of escape. In A 241 (omitted in second edition) Kant makes, however, the directly counter statement that definition of the categories is not possible, giving as his reason that, in isolation from the conditions of sensibility, they are merely logical functions, “without the slightest indication as to how they can possess meaning and objective validity.”[718]


It cannot be too often repeated that the Critique is not a unitary work, but the patchwork record of twelve years of continuous development. Certain portions of the transcendental deduction, of which A 76-9 is one, represent the latest of all the many stages; and their teaching, when accepted, calls for a radical recasting of the metaphysical deduction. The bringing of the entire Critique into line with its maturest parts would have been an Herculean task; and it was one to which Kant, then fifty-seven years of age, was very rightly unwilling to sacrifice the time urgently needed for the writing of his other Critiques. The passage before us is one of the many interpolations by which Kant endeavoured to give an external unity to what, on close study, is found to be the plain record of successive and conflicting views. Meantime, in dealing with this passage, we are concerned only to note that if this later mode of defining transcendental logic be accepted, far-reaching modifications in Kant’s Critical teaching have to be made. The other points developed in A 76-9 we discuss below[719] in their proper connection.

The same Function, etc.[720]—This passage has already been sufficiently commented upon.[721] Kant here expresses in quite inadequate fashion the standpoint of the transcendental deduction. The implication is that analytic and synthetic thinking are co-ordinate, one and the same faculty exercising, on these two levels, the same operations. The true Critical teaching is that synthetic thinking is alone fundamental, and that only by a regress upon it can judgments be adequately accounted for. This passage, like the preceding, may be of later origin than the main sections of the metaphysical deduction.

Term “Categories”[722] borrowed from Aristotle.—Cf. below, p. 198.

Table of Categories. Quantity.—Kant derives the category of unity from the universal,[723] and that of totality (Allheit)[724] from the singular. These derivations are extremely artificial. In Reflexionen, ii. 563, Kant takes the more natural line of identifying totality with the universal, and unity with the singular. Probably[725] the reason of Kant’s change of view is the necessity of obtaining totality by combining unity with multiplicity. That can only be done if universality is thus equated with unity. Watson’s explanation,[726] that Kant has reversed the order of the categories, seems to be erroneous.

Quality.—Cf. above, p. 192.

Relation.—The correlation of the categorical judgment{197} with the conception of substance and attribute is only possible[727] owing to Kant’s neglect of the relational judgment and to the dominance in his logical teaching of the Aristotelian substance-attribute view of predication. The correlation is also open to question in that the relation of subject and predicate terms in a logical judgment is a reversible one. It is a long step from the merely grammatical subject to the conception of that which is always a subject and never a predicate.

Kant’s identification of the category of community or reciprocity with the disjunctive judgment, though at first sight the most arbitrary of all, is not more so than many of the others. Its essential correctness has been insisted upon in recent logic by Sigwart, Bradley, and Bosanquet. In Kant’s own personal view[728] co-ordination in the form of co-existence is only possible through reciprocal interaction. The relation of whole and part (the parts in their relations of reciprocal exclusion exhausting and constituting a genuine whole) thus becomes, in its application to actual existences, that of reciprocal causation. The reverse likewise holds; interaction is only possible between existences which together constitute a unity.[729] Kant returns to this point in Note 3, added in the second edition.[730] The objection which Kant there considers has been very pointedly stated by Schopenhauer.

“What real analogy is there between the problematical determination of a concept by disjunctive predicates and the thought of reciprocity? The two are indeed absolutely opposed, for in the disjunctive judgment the actual affirmation of one of the two alternative propositions is also necessarily the negation of the other; if, on the other hand, we think of two things in the relation of reciprocity, the affirmation of one is also necessarily the affirmation of the other, and vice versa.”[731]

The answer to this criticism is on the lines suggested by Kant. The various judgments which constitute a disjunction do not, when viewed as parts of the disjunction, merely negate one another; they mutually presuppose one another in the total complex. Schopenhauer also fails to observe that in locating the part of a real whole in one part of space, we exclude it from all the others.[732]

Modality.—The existence of separate categories of modality{198} seems highly doubtful. The concepts of the possible and of the probable may be viewed as derivative; the notion of existence does not seem to differ from that of reality; and necessity seems in ultimate analysis to reduce to the concept of ground and consequence. These are points which will be discussed later.[733]

Aristotle’s ten categories[734] are enumerated by Kant in Reflexionen, ii. 522,[735] as: (1) substantia, accidens, (2) qualitas, (3) quantitas, (4) relatio, (5) actio, (6) passio, (7) quando, (8) ubi, (9) situs, (10) habitus; and the five post-predicaments as: oppositum, prius, simul, motus, habere. Eliminating quando, ubi, situs, prius, and simul as being modes of sensibility; actio and passio as being complex and derivative; and also omitting habitus (condition) and habere, as being too general and indefinite in meaning to constitute separate categories; we are then left with substantia, qualitas, quantitas, relatio, and oppositum. The most serious defect in this reduced list, from the Kantian point of view, is its omission of causality. It is, however, a curious coincidence that when substance is taken as a form of relatio, and oppositum as a form of quality, we are left with the three groups, quality, quantity, relation. Only modality is lacking to complete Kant’s own fourfold grouping. None the less, as the study of Kant’s Reflexionen sufficiently proves,[736] it was by an entirely different route that Kant travelled to his metaphysical deduction. Watson does not seem to have any ground for his contention[737] that the above modified list of Aristotle’s categories “gave Kant his starting-point.” It was there indeed, as the reference to Aristotle in his letter of 1772 to Herz shows, that he first looked for assistance, only, however, to be disappointed in his expectations.

Derivative concepts.[738]—Cf. above, pp. 66, 71-2.

I reserve this task for another occasion.[739]—Cf. A 204 = B 249; A 13; above, p. 66 ff., and below, pp. 379-80.

Definitions of categories omitted.[740]—Cf. above, pp. 195-6, and A 241 there cited; also below, pp. 339-42, 404-5.

Note 1.[741]—On this distinction between mathematical and dynamical categories cf. below, pp. 345-7, 510-11.

Note 2.[742]—This remark is inserted to meet a criticism which had been made by Johann Schulze,[743] and to which Kant in February 1784 had replied in terms almost identical with those of the present passage.{199}

“The third category certainly springs from the connection of the first and second, not, indeed, from their mere combination, but from a connection the possibility of which constitutes a concept that is a special category. For this reason the third category may not be applicable in instances in which the other two apply: e.g. one year, many years of future time, are real concepts, but the totality of future years, that is, the collective unity of a future eternity, conceived as entire (so to say, as completed), is something that cannot be thought. But even in those cases in which the third category is applicable, it always contains something more than the first and the second taken separately and together, namely the derivation of the second from the first, a process which is not always practicable. Necessity, for example, is nothing else than existence, in so far as it can be inferred from possibility. Community is the reciprocal causality of substances in respect of their determinations. But that determinations of one substance can be produced by another substance, is something that we may not simply assume; it is one of those connections without which there could be no reciprocal relation of things in space, and therefore no outer experience. In a word, I find that just as the conclusion of a syllogism indicates, in addition to the operations of understanding and judgment in the premisses, a special operation peculiar to reason ..., so also the third category is a special, and in part original, concept. For instance, the concepts, quantum, compositum, totum, come under the categories unity, plurality, totality, but a quantum thought as compositum would not yield the concept of totality unless the concept of the quantum is thought as determinable through the composition, and in certain quanta, such as infinite space, that cannot be done.”[744]

Kant’s assertion that in certain cases the third category is not applicable is misleading. His proof of the validity of the category of reciprocity in the third Analogy really consists in showing that it is necessary to the apprehension of spatial co-existence;[745] and if, as Kant maintains, consciousness of space is necessary to consciousness of time, it is thereby proved to be involved in each and every act of consciousness. It is presupposed in the apprehension even of substantial existence and of causal sequence. His proof that it is a unique category, distinct from the mere combination of the categories of substance and causality, does not, therefore, assume what his words in the above letter would seem to imply, that it is only occasionally employed. The same remark holds in regard to totality; it is presupposed even in the apprehension of a single year. Kant’s references, both here and in other parts of the Critique,[746] to totality in its bearing upon the conception of infinitude, reveal considerable{200} lack of clearness as to the relation in which it stands to the Idea of the unconditioned. Sometimes, as in this letter, he would seem to be identifying them; elsewhere this confusion is avoided. In B 111 totality is defined as multiplicity regarded as unity, and in A 142-3 = B 182 its schema is defined as number. (The identification of totality with number has led Kant to say in B 111 that number is not applicable in the representation of the infinite, a much more questionable assertion than that of the letter above quoted.) The statement that necessity is existence in so far as it can be inferred from possibility, or that it is existence given through possibility, is similarly misleading. Kant’s true position is that all three are necessary to the conception of any one of the three.

Thus Kant’s reply to Schulze, alike in his letter and in Note 2, fails to indicate with any real adequacy the true bearing of Critical teaching in this matter; and consequently fails to reveal the full force of his position. Only in terms of totality can unity and plurality be apprehended; only through the reciprocal relations which determine co-existence can we acquire consciousness of either permanence or sequence; only in terms of necessity can either existence or possibility be defined. The third category is not derived from a prior knowledge of the subordinate categories. It represents in each case a higher complex within which alone the simpler relations defined by the simpler concepts can exist or have meaning.

B 113-16, § 12.—This section, of no intrinsic importance, is an example of Kant’s loving devotion to this “architectonic.” His reasoning is extremely artificial, especially in its attempt to connect “unity, truth, and perfection” with the three categories of quantity. The Reflexionen show how greatly Kant was preoccupied with these three concepts, seeking either to base a table of categories upon them (B. Erdmann’s interpretation), or to reduce them to categories (Adickes’ interpretation). For some time Kant himself ranked with those who[747] “incautiously made these criteria of thought to be properties of the things in themselves.” In Reflexionen, ii. 903,[748] we find the following statement: “Unity (connection, agreement), truth (quality), completeness (quantity).” In ii. 916[749] Kant makes trial to connect them, as conceptions of possibility, with the categories of relation. In ii. 911 and 912 the later view, that they are logical in character and function, appears, but leads to their being set in relation to the three faculties of understanding, judgment, and reason. This is{201} conjectured by B. Erdmann to have been Kant’s view at the time of the first edition. ii. 915, 919, 920 present the view expounded in the section before us.[750] Erdmann[751] remarks that in this section Kant “is settling accounts with certain thoughts which in the ’seventies had yielded suggestions for the transformation of ontology into the transcendental analytic.{202}



First edition Subjective and Objective Deductions.—In dealing with the transcendental deduction, as given in the first edition, we can make use of the masterly and convincing analysis which Vaihinger[752] (building upon Adickes’ previous results, but developing an independent and quite original interpretation) has given of its inconsecutive and strangely bewildering argumentation. Vaihinger’s analysis is an excellent example of detective genius in the field of scholarship. From internal evidence, circumstantially supported by the Reflexionen and Lose Blätter, he is able to prove that the deduction is composed of manuscripts, externally pieced together, and representing no less than four distinct stages in the slow and gradual development of Kant’s views. Like geological deposits, they remain to record the processes by which the final result has come to be. Though they do not in their present setting represent the correct chronological order, that may be determined once the proper clues to their disentanglement have been duly discovered. That discovery is itself, however, no easy task; for the unexpected, while lending colour and incident to the commentator’s enterprise, baffles his natural expectations at every turn. The first stage is one in which Kant dispenses with the categories, and in which, when they are referred to, they are taken as applying to things in themselves. The last stage, worked out, as there is ground for believing, in the haste and excitement of the final revision, is not represented in the Prolegomena or in the second edition of the Critique, the author retracing his steps and resuming the standpoint of the stage which preceded it. The fortunate accident of Kant’s having jotted down upon the back of a dated paper the record of{203} his passing thought (one of the few Lose Blätter that are thus datable) is the culminating incident in this philosophical drama. It felicitously serves as a keystone in the body of evidence supported by general reasoning.

Before becoming acquainted with Vaihinger’s analysis I had observed Kant’s ascription to empirical concepts of the functions elsewhere allotted to the categories, but had been hopelessly puzzled as to how such teaching could be fitted into his general system. Vaihinger’s view of it as a pre-Critical survival would seem to be the only possible satisfactory solution. For the view which I have taken of Kant’s doctrine of the transcendental object as also pre-Critical, and for its employment as a clue to the dating of passages, I am myself alone responsible.

The order of my exposition will be as follows:[753]

I. Enumeration, in chronological order, of the four stages which compose the deduction of the first edition, and citation of the passages which represent each separate stage.

II. Detailed analysis, again in chronological order, of each successive stage, with exposition of the views which it embodies.

III. Examination of the evidence yielded by the Reflexionen and Lose Blätter in support of the above analysis.

IV. Connected statement and discussion of the total argument of the deduction.

I. Enumeration of the Four Stages

(1) First Stage: That of the Transcendental Object, without Co-operation of the Categories.—This stage is represented by[754]: (a) II. 3 (from beginning of the third paragraph to end of 3) = A 104-10; (b) I. § 13 (the entire section) = A 84-92 (retained in second edition as B 116-24). a discusses the problem of the reference of sensations to an object, b that of the objective validity of the categories. b is therefore transitional to the second stage.

(2) Second Stage: That of the Categories, without Co-operation of the Productive Imagination.—This stage is represented by: (a) I. [§ 14] (with the exception of its concluding paragraph) = A 92-4 (retained in second edition as B 124-7); (b) II. (the first four paragraphs) = A 95-7; (c) II. 4 (the entire section) = A 110-14.{204}

(3) Third Stage: That of the Productive Imagination, without Mention of the Threefold Transcendental Synthesis.—This stage is represented by (a) III.β (from beginning of seventh paragraph to end of twelfth) = A 119-23; (b) III. α (from beginning of third paragraph to end of sixth) = A 116-19; (c) I. § 14 (Concluding paragraph) = A 94-5; (d) III.δ (from beginning of sixteenth paragraph to end of section preceding summary) = A 126-8; (e) S(ummary) (in conclusion to III.) = A 128-30; (f) III.γ (from beginning of thirteenth paragraph to end of fifteenth) = A 123-6; (g) I(ntroduction) (from beginning of section to end of second paragraph) = A 115-16; (h) § 10 T(ransitional to the fourth stage) = A 76-9 (retained as B 102-4).

(4) Fourth Stage: That of the Threefold Transcendental Synthesis.—This stage is represented by: (a) II. 1-3 (from opening of 1 to end of second paragraph in 3) = A 98-104; (b) II. (the two paragraphs immediately preceding a) = A 97-8.

II. Detailed Analysis of the Four Stages

First Stage.—A 104-10; A 84-92 (B 116-24).

A 104-10; II. § 3.—This is the one passage in the Critique in which Kant explicitly defines his doctrine of the “transcendental object”; and careful examination of the text shows that by it he means the thing in itself, conceived as being the object of our representations. Such teaching is, of course, thoroughly un-Critical; and as I shall try to show, this was very early realised by Kant himself. The passages in which the phrase “transcendental object” occurs are, like the section before us, in every instance of early origin. It is significant that the transcendental object is not again referred to in the deduction of the first edition.[755] Though it reappears in the chapter on phenomena and noumena, it does so in a passage which Kant excised in the second edition. The paragraphs which he then substituted make no mention of it. The doctrine is of frequent occurrence in the Dialectic, and combines with other independent evidence to show that the larger part of the Dialectic is of early origin. That the doctrine of the transcendental object is thus a pre-Critical or semi-Critical survival has, so far as I am aware, not hitherto been observed by any writer upon Kant. It has invariably been interpreted in the light of the sections in which it does not occur, and, as thus toned down and tempered to something altogether{205} different from what it really stands for, has been taken as an essential and characteristic tenet of the Critical philosophy. It was in the course of an attempt to interpret Kant’s entire argument in the light of his doctrine of the transcendental object that I first came to detect its absence from all his later utterances. But it is important to recognise that the difficulties which would result from its retention are quite insuperable, and would by themselves, even in the absence of all external evidence of Kant’s rejection of it, compel us to regard it as a survival of pre-Critical thinking. As Vaihinger does not seem to have detected the un-Critical character of this doctrine, it is the more significant that he should, on other grounds, have felt constrained to regard the passage in which it is expounded as embodying the earliest stage in the development of the deduction. He would seem to continue in the orthodox view so far as to hold that though the doctrine of the transcendental object is here stated in pre-Critical terms, it was permanently retained by Kant in altered form.

The doctrine of the transcendental object, as here expounded, is as follows:

“Appearances are themselves nothing but sensuous representations which must not be taken as capable of existing in themselves (an sich) with exactly the same character (in ebenderselben Art) outside our power of representation.”[756]

These sense-representations are our only possible representations, and when we speak of an object corresponding to them, we must be conceiving an object in general, equal to x.

“They have their object, but an object which can never be intuited by us, and which may therefore be named the non-empirical, i.e. transcendental object = x.”[757]

This object is conceived as being that which prevents our representations from occurring at haphazard, necessitating their order in such manner that, manifold and varied as they may be, they can yet be self-consistent in their several groupings, and so possess that unity which is essential to the concept of an object.

“The pure concept of this transcendental object, which in fact throughout all our knowledge is always one and the same, is that which can alone confer upon all our empirical concepts relation in general to an object, i.e. objective reality.”[758]


What renders this doctrine impossible of permanent retention was that it allowed of no objective existence mediate between the merely subjective and the thing in itself. On such teaching there is no room for the empirical object; and immediately upon the recognition of that latter phenomenal form of existence in space, Kant was constrained to recognise that it is in the empirical object, not in the thing in itself, that the contents of our representations are grounded and unified. Any other view must involve the application of the categories, especially those of substance and causality, to the thing in itself. The entire empirical world has still to be conceived as grounded in the non-empirical, but that is a very different contention from the thesis that the thing in itself is the object and the sole object of our representations. The doctrine of the transcendental object has thus a twofold defect: it advocates an extreme subjectivism, and yet at the same time applies the categories to the thing in itself.

But the latter consequence is one which could not, at the stage represented by this section, be appreciated by Kant. For, as we shall find, he is endeavouring to solve the problem of the reference of sense-representation to an object without assumption of a priori categories. It is in empirical concepts, conditioned only by a transcendental apperception, that he professes to discover the grounds and conditions of this objective reference. Let us follow Kant’s argument in detail. The section opens[759] with what may be a reference to the Aesthetic, and proceeds to deal with the first of the two problems cited in the 1772 letter to Herz[760]—how sense-representations stand related to their object. The exact terms in which this question was there formulated should be noted.

“I propounded to myself this question: on what ground rests the relation of that in us which we name representation (Vorstellung) to the object. If the representation contains only the mode in which the subject is affected by the object, it is easily understood how it should accord (gemäss sei) with that object as an effect with its cause, and how [therefore] this determination of our mind should be able to represent something, i.e. have an object. The passive or sensuous representations have thus a comprehensible (begreifliche) relation to objects, and the principles, which are borrowed from the nature of our soul, have a comprehensible validity for all things in so far as they are to be objects of the senses.”[761]

Thus in 1772 there was here no real problem for Kant. The assumed fact, that our representations are generated in{207} us by the action of independent existences, is taken as sufficient explanation of their being referred to objects.

The section of the Critique under consideration shows that Kant had come to realise the inadequacy of this explanation quite early, indeed prior to his solution of the second and further question which in that same letter is spoken of as “the key to the whole secret” of metaphysics. On what grounds, he now asks, is a subjective idea, even though it be a sense impression, capable of yielding consciousness of an object? In the letter to Herz the use of the term representation (Vorstellung) undoubtedly helped to conceal this problem. It is now emphasised that appearances are nothing but sense representations, and must never be regarded as objects capable of existing in themselves, with exactly the same character, outside our power of representation. Now also Kant employs, in place of the phrase “in accord with,” the much more definite term “corresponding to.” He points out that when we speak of an object corresponding to our knowledge, we imply that it is distinct from that knowledge. Consciousness of such an object must therefore be acquired from some other source than the given impressions. In other words, Kant is now prepared to withdraw his statement that “the passive or sensuous representations have an [easily] comprehensible relation to objects.” In and by themselves they are purely subjective, and can involve no such concept. The latter is a thought (Gedanke), a concept (Begriff), additional to, and distinct from, the given impressions. Its possibility, as regards both origin[762] and validity, must be “deduced.”

There then results this first and very peculiar form of the transcendental deduction. That part of it which persists in the successive stages rests upon an explicitly developed distinction between empirical and transcendental apperception. Kant teaches, in agreement with Hume, though, as we may believe, independently of his direct influence, that there is no single empirical state of the self which is constant throughout experience.[763]

“The consciousness of the self, according to the determinations of our state in inner perception, is merely empirical, and always in process of change.... That which has to be represented as of necessity numerically identical cannot be thought as such through empirical data. There must be a condition which precedes all experience, and renders experience itself possible, if a transcendental pre-supposition of this kind is to be rendered valid.... This pure,{208} original, unchangeable consciousness I shall name transcendental apperception.”[764]

Kant would seem to have first developed this view in a quite crude form. The consciousness of the self, he seems to have held, consists in its awareness of its own unceasing activities. As consciousness of activity, it is entirely distinct in nature and in origin from all apprehension of sense impressions.[765] This teaching is a natural extension of the doctrine of the Dissertation,[766] that such pure notions as those of possibility, existence, necessity, substance, cause, are “acquired by attending to the actions of the mind on the occasion of experience.” Kant would very naturally hold that consciousness of the identity and unity of the self is obtained in a similar manner. Such, indeed, is the teaching of the section before us.

“No knowledge can take place in us ... without that unity of consciousness which precedes all data of intuitions, and in relation to which all representation of objects is alone possible.”[767] “It is precisely this transcendental apperception that constructs out of (macht aus) all possible appearances, which are capable of coexisting in one experience, a connection of all these representations according to laws. For this unity of consciousness would be impossible if the mind could not become conscious, in the knowledge of the manifold, of the identity of the function whereby it combines it synthetically in one knowledge. Thus the mind’s original and necessary consciousness of the identity of itself is at the same time a consciousness of an equally necessary unity of the synthesis of all appearances according to concepts, i.e. according to rules.... For the mind could not possibly think the identity of itself in the manifold of its representations, and indeed a priori, if it did not have before its eyes the identity of its action....”[768]

That is to say, the self is the sole source of all unity. As a pure and original unity it precedes experience; to its synthetic activities all conceptual unity is due; and by reflection upon the constancy of these activities it comes to consciousness of its own identity.

“...even the purest objective unity, namely that of the a priori concepts (space and time), is possible only through relation{209} of the intuitions to [transcendental apperception]. The numerical unity of this apperception is therefore the a priori condition of all concepts, just as the manifoldness of space and of time is of the intuitions of sensibility.”[769]

To this consciousness of the abiding unity of the self Kant also traces the notion of the transcendental object. The latter, he would seem to argue, is formed by analogy from the former.

“This object is nothing else than the subjective representation (of the subject) itself, but made general, for I am the original of all objects.”[770] “The mind, through its original and underived thinking, is itself the pattern (Urbild) of such a synthesis.”[771] “I would not represent anything as outside me, and so make [subjective] appearances into objective experience if the representations were not related to something which is parallel to my ego, and so in that way referred by me to another subject.”[772]

These quotations from the Lose Blätter would seem to contain the key to Kant’s extremely enigmatic statement in A 105, that “the unity which the object makes necessary can be nothing else than the formal unity of consciousness in its synthesis of the manifold of its representations,” and again in A 109, that “this relation [of representations to an object] is nothing else than the necessary unity of consciousness.”[773]

But this does not complete the sum-total of the functions which Kant is at this stage prepared to assign to apperception. It mediates our consciousness of the transcendental object in still another manner, namely, by rendering possible the formation of the empirical concepts which unify and direct its synthetic activities. This is, indeed, the feature in which this form of the deduction diverges most radically from all later positions. Space and time are, it would seem, regarded as being the sole a priori concepts.[774] The instruments through which the unity of apperception acts, and through which the thought of an object becomes possible, are empirical concepts. Such general concepts as “body” or “triangle” serve as rules constraining the synthetic processes of apprehension and{210} reproduction to take place in such unitary fashion as is required for unitary consciousness. The notion of objectivity is specified in terms of the necessities which these empirical concepts thus impose.

“We think a triangle as object in so far as we are conscious of the combination of three straight lines according to a rule by which such an intuition can at all times be generated. This unity of rule determines the whole manifold and limits it to conditions which make the unity of apperception possible; and the concept of this unity [of rule] is the representation of the object.... All knowledge demands a concept, ... and a concept is always, as regards its form, something general, something that serves as a rule. Thus the concept of body serves as a rule to our knowledge of outer appearances, in accordance with the unity of the manifold which is thought through it.... The concept of body necessitates ... the representation of extension, and therewith of impenetrability, shape, etc.”[775]

Such is the manner in which Kant accounts for our concept of the transcendental object. It consists of two main elements: first, the notion of an unknown x, to which representations may be referred; and secondly, the consciousness of this x as exercising compulsion upon the order of our thinking. The former notion is framed on the pattern of the transcendental subject; it is conceived as another but unknown subject. The consciousness of it as a source of external necessity is mediated by the empirical concepts which transcendental apperception also makes possible. And from this explanation of the origin of the concept of the transcendental object Kant derives the proof of its validity.[776] It is indispensable for the realisation by the unitary self of a unitary consciousness.

“This relation [of representations to an object] is nothing else than the necessary unity of consciousness, and therefore also of the synthesis of the manifold, by a common (gemeinschaftlich) functioning of the mind, which unites it in one representation.”[777]

Through instruments empirical in origin, and subjectively necessary, the notion of an objective necessity is rendered possible to the mind.

It is not surprising that Kant did not permanently hold to this view of the empirical concept. The objections are obvious. Such a view of the function of general concepts renders unintelligible their own first formation. For as they{211} are empirical, they can only be acquired by conscious processes that do not involve them. That is to say, consciousness of objects follows upon a prior consciousness in and through which concepts, such as that of body, are discovered and formed. Yet, as the argument claims, general concepts are the indispensable conditions of unitary consciousness. How through a consciousness that is not yet unified can general concepts be formed? Also it is difficult to see how empirical concepts can be viewed as directly conditioned by, and as immediately due to, anything so general as pure apperception. These objections Kant must have come very quickly to recognise. This was the first part of his teaching to be modified. In the immediately succeeding stage,[778] so far as the stages can be reconstructed from the survivals in the Critique, the empirical concepts are displaced once and for all by the a priori categories.

The only sentences which can be regarded as possibly conflicting with the above interpretation are those two (in the second last and in the last paragraphs) in which the phrase “rules a priori” occurs. Even granting (what is at least questionable as regards the first) that the words are meant to be taken together, it does not follow that Kant is here speaking of categories. For contrary to his usual teaching he speaks of the concept of body as a source of necessity. If so, it may well, with equal looseness, be spoken of as a priori. That is indeed done, by implication, in the second and third paragraphs, where he speaks of a rule (referring to “body and triangle”) as making the synthesis of reproduction “a priori necessary.” Such assertions are completely inconsistent with Kant’s Critical teaching, but so is the entire section.

The setting in which the passage before us occurs has its own special interest.[779] When Kant, as it would seem, on the very eve of the publication of the Critique, developed the doctrine of a threefold synthesis culminating in a “synthesis of recognition in the concept,” he must have bethought himself of this earlier position, and have completed his subjective deduction by incorporation, probably with occasional alterations of phrasing, of the older manuscript. This procedure has bewildered even the most discerning among Kant’s readers; but now, thanks to Vaihinger’s convincing analysis, it may be welcomed as of illuminating interest in the historical study of Kant’s development.

I may here draw attention to the two important respects{212} in which the positions revealed in this section continued to influence Kant’s later teaching: namely, in the emphasis laid upon the transcendental unity of apperception, and in the view of objectivity as involving the thought of the thing in itself.

The excessive emphasis which in this first stage is laid upon the transcendental unity of apperception persists throughout the later forms of the deduction, and, as I shall try to show, does so to the detriment of the argument. Though its functions are considerably diminished, they are still exaggerated; this is perhaps in part due to its having been in this early stage regarded as in and by itself the sole ultimate ground of unitary experience. There were, however, two other influences at work. Kant continued to employ the terminology of his earlier view, and in his less watchful moments was betrayed thereby into conflict with his considered teaching. But even more important was the influence of his personal convictions. He was irrevocably committed in his own private thinking to a belief in the spiritual and abiding character of the self; and this belief frequently colours, in illegitimate ways, the expression of his views. This is especially evident in some of the alterations[780] of the second edition, written as they were at a time when he was chiefly preoccupied with moral problems.

As regards the other factor, the view adopted in regard to the nature of objectivity, there is ample evidence that even after the empirical concepts had been displaced by the categories Kant still continued for some time (possibly for several years in the earlier and middle ’seventies) to hold to his doctrine of the transcendental object. Passages which expound it in this later form occur in the Note on Amphiboly and throughout the Dialectic.[781] That this may not be taken for his final teaching is equally certain. The entire first layer of the deduction of the first edition, all the relevant passages in the chapter on phenomena and noumena, and some of those in the Dialectic, were omitted in the second edition; and nowhere, either in the other portions of the deduction of the first edition, or in the deduction of the second edition, or in any passages added elsewhere in the second edition, is such teaching to be found.

A brief statement of Kant’s doctrine of the transcendental object in its later form seems advisable at this point; it is required in order to complete and to confirm the interpretation{213} which I have given of the earlier exposition. At the same time I shall endeavour to show that the sections in which the doctrine occurs, though later than the first layer of the deduction of the first edition, are all of comparatively early origin, and that they reveal not the least trace of Kant’s more mature, phenomenalist view of the empirical world in space.

We may begin with the passages in the chapter on phenomena and noumena. The meaning in which the term transcendental is employed is there made sufficiently clear.

“The transcendental employment of a concept in any principle consists in its being referred to things in general and in themselves.”[782]

That is to say, the term transcendental, as used in the phrase transcendental object, is not employed in any sense which would oppose it to the transcendent. In so far as the thought of the thing in itself is a necessary ingredient in the concept of objectivity, it is a condition of apperception, and therefore of possible experience; in other words, the thought of a transcendent object is one of the transcendental conditions of our experience. As Kant is constantly interchanging the terms transcendent and transcendental, such an explanation of the phrase is perhaps superfluous; but if any is called for, the above would seem to suffice. As we shall have occasion to observe,[783] other factors besides the a priori must be reckoned among the conditions of experience; and to both types of conditions Kant applies the epithet transcendental.

In the chapter on phenomena and noumena Kant enquires at considerable length whether the categories (meaning, of course, the pure forms of understanding, not their schematised correlates) allow of transcendental (i.e. transcendent) employment. The passages in which this discussion occurs[784] would seem, however, to be highly composite; many paragraphs, or portions of paragraphs, are of much later date than others. We may therefore limit our attention to those in which the phrase transcendental object is actually employed, i.e. to those which appear only in the first edition.

“All our representations are referred by the understanding to some object; and since appearances are merely representations, the understanding refers them to a something as the object of sensuous intuition. But this something, thus conceived (in so fern), is only the transcendental object; and by that is meant a something = x, of which we know, and with the present constitution of our understanding can know, nothing whatsoever, but which, as a correlate of the unity of apperception, can serve only for the unity{214} of the manifold in sensuous intuition. By means of this unity the understanding combines the manifold into the concept of an object. This transcendental object cannot be separated from the sense data, for nothing then remains over through which it might be thought. Consequently it is not in itself an object of knowledge, but only the representation of appearances under the concept of an object in general which is determinable through the manifold of those appearances. Precisely for this reason also the categories do not represent a special object given to the understanding alone, but only serve to specify the transcendental object (the concept of something in general) through that which is given in sensibility, in order thereby to know appearances empirically under concepts of objects.”[785] “The object to which I relate appearance in general is the transcendental object, i.e. the completely indeterminate thought of something in general. This cannot be entitled the noumenon [i.e. the thing in itself more specifically determined as being the object of a purely intelligible intuition];[786] for I know nothing of what it is in itself, and have no concept of it save as the object of a sensuous intuition in general, and so as being one and the same for all appearances.”[787]

Otherwise stated, Kant’s teaching is as follows. The thought of the thing in itself remains altogether indeterminate; it does not specify its object, and therefore yields no knowledge of it; none the less it is a necessary ingredient in the concept of objectivity as such. The object as specified in terms of sense is mere representation; the object as genuinely objective can only be thought. The correlate of the unity of apperception is the thought of the thing in itself. This is what Kant is really asserting, though in a hesitating manner which would seem to indicate that he is himself already more or less conscious of its unsatisfactory and un-Critical character.

The phrase transcendental object occurs once in the second Analogy[788] and twice in the Note on Amphiboly.[789] The passage in the second Analogy may very well, in view of the kind of subjectivism which it expounds, be of early date of writing. By transcendental object Kant there quite obviously means the thing in itself. From the first reference in the Note on Amphiboly no definite conclusions can be drawn. The argument is too closely bound up with his criticism of Leibniz to allow of his own independent standpoint being properly developed. There is, however, nothing in it which compels us to regard it as of late origin; and quite evidently Kant here means by the transcendental object the thing in itself. The phrase substantia phaenomenon is not, as might at first sight seem, equivalent to the empirical object of Kant{215}’s phenomenalist teaching. It is an adaptation of Leibnizian phraseology.[790] The second reference in the Note on Amphiboly occurs in a passage which may perhaps be of later origin;[791] but the transcendental object is there mentioned only in order to afford opportunity for the statements that it cannot be thought through any of the categories, that we are completely ignorant whether it is within or without us, and whether if sensibility were removed it would vanish or remain, and that it can therefore serve only as a limiting concept. We here observe it in the very process of being eliminated. As we shall find, Kant’s teaching is ill-expressed in the sections on Amphiboly; so much so that they could not be recast without seriously disturbing the balance of his architectonic. They were therefore allowed to remain unaltered in the second edition.

We may now pass to the Dialectic. The subjectivist doctrine of the transcendental object is there expressed in a much more uncompromising manner. Let us first consider the references to the transcendental object in the Paralogisms and in the subsequent Reflection. The phrase transcendental object occurs twice in the second Paralogism, once in the third, twice in the fourth, and three times in the Reflection;[792] and in all these cases there is not the least uncertainty as to its denotation. It is taken as equivalent to the thing in itself, and is expounded as a necessary ingredient in the consciousness of our subjective representations as noumenally grounded.

“What matter may be as a thing in itself (transcendental object) is completely unknown to us, though, owing to its being represented as something external, its permanence as appearance can indeed be observed.”[793] “We can indeed admit that something, which may be (in the transcendental[794] sense) ‘outside us,’ is the cause of our outer intuitions, but this is not the object of which we are thinking in the representations of matter and of corporeal things, for these are merely appearances, i.e. mere kinds of representation which are never to be met with save in us, and whose actuality depends on immediate consciousness just as does the consciousness of my own thoughts. The transcendental object is equally unknown in respect to inner and to outer intuition.”[795]


Here Kant at one and the same time distinguishes between, and confounds together, representation and its empirical object. What is alone clear is that by the transcendental object he means simply the thing in itself viewed as the cause of our sensations. In A 358 it is used in a wider sense as also comprehending the noumenal conditions which underlie the conscious subject.

“...this something which underlies the outer appearances and which so affects our sense that it obtains the representations of space, matter, shape, etc., this something viewed as noumenon (or better as transcendental object) might also at the same time be the subject that does our thinking....”

Similarly in A 379-80:

“Though the I, as represented through inner sense in time, and objects in space outside me, are specifically quite distinct appearances, they are not for that reason thought as being different things. Neither the transcendental object which underlies outer appearances, nor that which underlies inner intuition, is in itself either matter or a thinking being, but is a ground (to us unknown) of the appearances which supply to us the empirical concepts of the former as well as of the latter kind.”

The references in the Reflection on the Paralogisms are of the same general character and are equally definite.[796] A 390-1 has special interest in that it explicitly states that to appearances, taken as Kant invariably takes them throughout the Paralogisms in the first edition as mere subjective representations, the category of causality, and therefore by implication the category of substance, is inapplicable.

“No one could dream of asserting that that which he has once come to recognise as mere representation is an outer cause.”

We may now turn to the passages in the chapter on the Antinomies.

“The non-sensuous cause of our representations is completely unknown to us, and therefore we cannot intuit it as object.... We may, however, entitle the purely intelligible cause of appearances in general the transcendental object.... To this transcendental object we can ascribe the whole extent and connection of our possible perceptions....”[797]

Appearances can be regarded as real only to the extent to which they are actually experienced. Otherwise they exist only in some unknown noumenal form of which we can{217} acquire no definite concept, and which is therefore really nothing to us. This, Kant declares, is true even of that immemorial past of which we are ourselves the product.

“...all the events which have taken place in the immense periods that have preceded my own existence mean really nothing but the possibility of extending the chain of experience from the present perception back to the conditions which determine it in time.”[798]

In other words, we may not claim that such events, empirically conceived, have ever actually existed in any such empirical form. A similar interpretation is given to the assertion of the present reality of what has never been actually experienced.

“Moreover, in outcome it is a matter of indifference whether I say that in the empirical progress in space I can meet with stars a hundred times farther removed than the outermost now perceptible to me, or whether I say that they are perhaps to be met with in cosmical space even though no human being has ever perceived or ever will perceive them. For though they might be given as things in themselves, without relation to possible experience, they are still nothing for me, and therefore are not objects, save in so far as they are contained in the series of the empirical regress.”[799] “The cause of the empirical conditions of this process, that which determines what members I shall meet with and how far by means of such members I can carry out the regress, is transcendental and is therefore necessarily unknown to me.”[800]

Such is the form in which Kant’s pre-Critical doctrine of the transcendental object survives in the Critique.[801] It contains no trace of the teaching of the objective deduction of the first and second edition or of the teaching of the refutation of idealism in the second edition. It closely resembles Mill’s doctrine of the permanent possibilities of sensation, and is almost equally subjectivist in character. As already noted,[802] it also lies open to the further objection that it involves an illegitimate application of the categories to things in themselves. As Kant started from the naïve and natural assumption that reference of representations to objects must be their reference to things in themselves, he also took over the current Cartesian view that it is by an inference in terms of the category of causality that we advance from a representation to its cause. The thing in itself is regarded as the sole true substance and as the real cause of everything {218}which happens in the natural world. Appearances, being representations merely, are wholly transitory and completely inefficacious. Not only, therefore, are the categories regarded as valid of things in themselves, they are also declared to have no possible application to phenomena. Sense appearances do not, on this view, constitute the mechanical world of the natural sciences; they have a purely subjective, more or less epi-phenomenal, existence in the mind of each separate observer. It was very gradually, in the process of developing his own Critical teaching, that Kant came to realise the very different position to which he was thereby committed. The categories, including that of causality, are pre-empted for the empirical object which is now regarded as immediately apprehended; and the function of mediating the reference of phenomena to things in themselves now falls to the Ideas of Reason. The distinction between appearance and reality is no longer that between representations and their noumenal causes, but between the limited and relative character of the entire world in space and time and the unconditioned demanded by Reason. But these are questions whose discussion must meantime be deferred.[803]

I may now briefly summarise the evidence in favour of the view that the doctrine of the transcendental object is a pre-Critical or semi-Critical survival and must not be taken as forming part of Kant’s final and considered position. (I) Of the six sections in which the phrase transcendental object occurs, three[804] were omitted in the second edition, and in the passages which were substituted for them it receives no mention. There are various reasons which can be suggested in explanation of the retention of the other three[805] in the second edition. The Note on Amphiboly was too unsatisfactory as a whole to encourage Kant to improve upon it in detail. The other two are outside the limit at which Kant thought good to terminate all attempts to improve, whether in major or in minor matters, the text of the first edition.[806] To have recast the Antinomies as he had recast the Paralogisms{219} would have involved alterations much too extensive. Also, there were no outside polemical influences—or at least none acting quite directly—such as undoubtedly reinforced his other reasons for revising the Paralogisms. (2) Secondly, the transcendental object is not mentioned in the later layers of the deduction of the first edition, nor in the deduction of the second edition, nor in any passage or note added in the second edition. That Kant should thus suddenly cease to employ a phrase to which he had accustomed himself is the more significant in view of his conservative preference for the adapting of familiar terminology to new uses. It can only be explained as due to his recognition of the completely untenable character of the teaching to which it had given expression. As the object of knowledge is always empirical, it can never legitimately be called transcendental. (3) Thirdly, the general teaching of the passages in which the phrase transcendental object occurs is by itself sufficient proof of their early origin. They reveal not the least trace of the deepened insight of his final standpoints. As we know, it was certain difficulties involved in the working out of the objective deduction that delayed the publication of the Critique for so many years; and the sections which deal with these difficulties contain Kant’s maturest teaching. In them he seems to withdraw definitely from the positions to which he had unwarily committed himself by his un-Critical doctrine of the transcendental object. I now pass to the second section constitutive of the first stage.

A 84-92=B 116-24, I. § 13.—Just as in II. § 3 Kant deals solely with the first of the two questions formulated in the letter of 1772 to Herz—the reference of sense-representations to an object,—so in I. § 13 he raises only the second—that of the objective validity of intellectual representations (now spoken of as pure concepts of understanding, or pure a priori concepts, and only in one sentence as categories). And just as in the former section he carries the problem a step further, yet without attaining to the true Critical position, so in this latter he still assumes that it is the application of these pure concepts to real independent objects, i.e. to things in themselves, which calls for justification. We must again consider the exact terms in which this problem is formulated in the letter to Herz.[807]

“Similarly, if that in us which is called a representation, were active in relation to the object, that is to say, if the object itself were produced by the representation (as on the view that the ideas{220} in the Divine Mind are the archetypes of things), the conformity of representations with objects might be understood. We can thus render comprehensible at least the possibility of two kinds of intelligence—of an intellectus archetypus, on whose intuition the things themselves are grounded, and of an intellectus ectypus which derives the data of its logical procedure from the sensuous intuition of things. But our understanding (leaving moral ends out of account) is not the cause of the object through its representations, nor is the object the cause of its intellectual representations (in sensu reali). Hence, the pure concepts of the understanding cannot be abstracted from the data of the senses, nor do they express our capacity for receiving representations through the senses. But, whilst they have their sources in the nature of the soul, they originate there neither as the result of the action of the object upon it, nor as themselves producing the object. In the Dissertation I was content to explain the nature of these intellectual representations in a merely negative manner, viz. as not being modifications of the soul produced by the object. But I silently passed over the further question, how such representations, which refer to an object and yet are not the result of an affection due to that object, can be possible. I had maintained that the sense representations represent things as they appear, the intellectual representations things as they are. But how then are these things given to us, if not by the manner in which they affect us? And if such intellectual representations are due to our own inner activity, whence comes the agreement which they are supposed to have with objects, which yet are not their products? How comes it that the axioms of pure reason about these objects agree with the latter, when this agreement has not been in any way assisted by experience? In mathematics such procedure is legitimate, because its objects only are quantities for us, and can only be represented as quantities, in so far as we can generate their representation by repeating a unit a number of times. Hence the concepts of quantity can be self-producing, and their principles can therefore be determined a priori. But when we ask how the understanding can form to itself completely a priori concepts of things in their qualitative determination, with which these things must of necessity agree, or formulate in regard to their possibility principles which are independent of experience, but with which experience must exactly conform,—we raise a question, that of the origin of the agreement of our faculty of understanding with the things in themselves, over which obscurity still hangs.”[808]

The section before us represents the same general standpoint as that given in the above letter. Here, too, it is the validity of the a priori concepts in reference to things in themselves that is under consideration. The implication of Kant’s argument is that the categories, being neither determinable nor discoverable by means of experience, will only apply{221} to appearances if they determine, or rather reveal, the actual non-experienced nature of things in themselves. These pure concepts, it is implied, owing to their combined a priori and intellectual characteristics, make this inherent claim. Either they are altogether empty and illusory, or such unlimited validity must be granted to them. Kant, that is to say, still holds, as in the Dissertation, that sense-representations reveal things as they appear, intellectual representations things as they are.

“We have either to surrender completely all claims to judgments of pure reason, in the most esteemed of all fields, that which extends beyond the limits of all possible experience, or we must bring this Critical investigation to perfection.”[809]

The pure concepts, unlike space, “apply to objects generally, apart from the conditions of sensibility.”[810] But here also, as in the letter to Herz, the strange and problematic character of such knowledge is clearly recognised.

Kant’s discussion of the concept of causality in A 90 may seem to conflict with the above contention—that it is its applicability to things in themselves which Kant is considering. But this difficulty vanishes if we bear in mind that here, as in the Dissertation, there is no such distinction as we find in Kant’s later more genuinely phenomenalist position, between the objects causing our sensations and things in themselves.[3] The purely intelligible object, supposed to remain after elimination of the empirical and a priori sensory factors, is the thing in itself. The objects apprehended through sense are real, only not in their sensuous form.

There are two connected facts which together may perhaps be taken as evidence that I. § 13 is later than II. 3 b. Intellectual concepts are reinstated alongside the a priori concepts of space and time. Kant has evidently in the meantime given up the attempt to construe the former as empirical in origin. That that attempt was earlier in time would seem to be proved by the further fact, that the a priori concepts are here viewed as performing the same kind of function as that ascribed in II. 3 b to concepts that are empirical. They are conditions of the “synthetic unity of thought.”[811] This view of the function of concepts is certainly fundamental and important, and Kant permanently retained it from his previous abortive method of ‘deduction.’ But it was a long step from the discovery of the distinction between empirical and a priori {222}concepts to its fruitful application. That involved appreciation of the further fact that the two problems, separately stated in the letter to Herz and separately dealt with in II. 3 b and in I. § 13—the problem of the relation of sense-representations, and the problem of the relation of intellectual representations, to an object,—are indeed one and the same, soluble from one and the same standpoint, by one and the same method of deduction, namely, by reference to the possibility of experience. Only in and through relation to an object can sense-representations be apprehended; and only as conditions of such sense-experience are the categories objectively valid. Relation to an object is constituted by the categories, and is necessary in reference to sense-representations, because only thereby is consciousness of any kind possible at all.

That this truly Critical position had not been attained when I. § 13 was written,[812] is shown not only by its concentration on the single problem of the validity of a priori concepts, but also by its repeated assertion that representations can be consciously apprehended independently of all relation to the faculty of understanding. The directly counter assertion appears, however, in the sections (I. § 14, II.: first four paragraphs) which immediately follow in the text of the Critique—indicating that in the period represented by these latter the revolutionary discovery, the truly Copernican hypothesis, had at last been achieved. They constitute the second stage, and to it we may now proceed.

Second Stage.—A 92-4 = B 124-7; A 95-7; A 110-14.

A 92-4, I. § 14 (with the exception of the concluding classification of mental powers).—This section makes a fresh start; it stands in no necessary relation to any preceding section. The problem is still formulated, in its opening sentences, in terms reminiscent of the letter to Herz; but otherwise the standpoint is entirely new, and save for the wording of a single sentence (A 93: “if not intuited, yet”), is genuinely Critical. The phrase “possibility of experience” now appears, and is at once assigned the central rôle. The words “if not intuited, yet” in A 93 may possibly have been inserted later in order to tone down the flagrant contradiction with the preceding paragraphs. In any case, even this qualification is explicitly retracted in A 94.

A 95-7.—The same standpoint appears in the first three paragraphs of Section II. The categories are “the a priori{223} conditions on which the possibility of experience depends.”[813] By the categories alone “can an object be thought.”[814] The further important point that only in their empirical employment do the categories have use and meaning is excellently developed.

“An a priori concept not referring to experience would be the logical form only of a concept, but not the concept itself by which something is thought.”[815]

A 110-14, II. 4.—In this section also the argument starts afresh, indicating (if such evidence were required) that, like I. § 14, it must have been written independently of its present context. But the argument is now advanced one step further. The categories are recognised as simultaneously conditioning both unity of consciousness and objectivity.

“There is but one experience ... as there is but one space and one time....” “The a priori conditions of a possible experience are at the same time conditions of the possibility of objects of experience”[816] “...the necessity of these categories rests on the relation which our whole sensibility, and with it also all possible appearances, have to the original unity of apperception....”[817]

Now also it is emphasised that save in and through a priori concepts no representations can exist for consciousness.

“They would then belong to no experience, would be without an object, a blind play of representations, less even than a dream.”[818] They “would be to us the same as nothing.”[819]

The wording is still not altogether unambiguous, but the main point is made sufficiently clear.

These paragraphs are the earliest in which traces of a genuine phenomenalism can be detected. The transcendental object, one and the same for all our knowledge, is not referred to. ‘Objects’ (in the plural) is the term which is used wherever the context permits. The empirical object is thus made to intervene between the thing in itself and the subjective representations. But the distinction between empirical objects and subjective representations on the one hand, and between empirical objects and things in themselves on the other, is not yet drawn in any really clear and definite manner.

A similar phenomenalist tendency crops out in Kant’s distinction[820] between objective affinity and subjective association.{224}

“The ground of the possibility of the association of the manifold, so far as it lies in the object, is named the affinity of the manifold.”

None the less Kant’s subjectivism finds one of its most decided expressions in A 114.

Third Stage.—A 119-23 = III. β; A 116-19 = III. α; A 94-5 = I. § 14 C(oncluding paragraph); A 126-8 = III. δ; A 128-30 = S(ummary); A 123-6 = III. γ; A 115-16 = III. I(ntroduction); A 76-9 (B 102-4) = § 10 T(ransition to fourth stage).

A 119-23, III. β (from the beginning of the seventh paragraph to the end of the twelfth). The doctrine of objective affinity already developed in the above sections is now made to rest upon a new faculty, the productive imagination. As Vaihinger remarks, the wording of this section would seem to indicate that it is Kant’s first attempt at formulating that new doctrine. He has not as yet got over his own surprise at the revolutionary nature of the conclusions to which he feels himself driven by the exigencies of Critical teaching. He finds that it is deepening into consequences which may lead very far from the current psychology and from his own previous views regarding the nature and conditions of the knowing process and of personality. As evidence that this section was not written continuously with II. 4, [821a] we have the further fact that though the doctrine of objective affinity is dwelt upon, it is described afresh, with no reference to the preceding account. Also, the empirical processes of apprehension and reproduction, already mentioned in A 104-10, are now ascribed to the empirical imagination which is carefully distinguished from the productive.

III. α repeats “from above” the argument given in III. β “from below.” It insists upon the close connection between the categories (first introduced in II. 4[821]) with the productive imagination of III. β.

Vaihinger places III. δ next in order, on account of the connection of its argument with III. α.[822] But it dwells only upon the chief outcome of the total argument, viz. that the orderliness of nature is due to understanding. That productive imagination is not mentioned, is taken by Vaihinger to signify Kant’s recognition that it can be postulated only hypothetically, and that as doctrine it is not absolutely essential to the strict deduction.{225}

S summarises the entire argument, and in it “pure imagination” receives mention.

Within this third stage III. γ is subsequent to the above four sections. For it carries the doctrine of productive imagination one step further. In III. β, III. α, and S, productive imagination has been treated merely as an auxiliary function of pure understanding.

“The unity of apperception in relation to the synthesis of imagination is the understanding; and the same unity with reference to the transcendental synthesis of the imagination is the pure understanding.”[823]

It is now treated as a separate and distinct faculty. So far from being a function of understanding, its synthesis “by itself, though carried out a priori, is always sensuous.”[824] It is

“one of the fundamental faculties of the human soul.... The two extreme ends, sensibility and understanding, must be brought into connection with each other by means of this transcendental function of imagination.”[825]

In this section there also appears a new element which would seem to connect it with the next following stage, namely, the addition to the series, apprehension, association, and reproduction, of the further process, recognition. As here introduced it is extremely ambiguous in character. It is counted as being empirical, and yet as containing a priori concepts. This decidedly hybrid process would seem to represent Kant’s first formulation of the even more ambiguous process, which corresponds to it in the fourth stage.

In III. I recognition is again mentioned, but this time in a form still more akin to its treatment in the fourth stage. It is not recognition through categories, but, as a form in apperception, is the

“empirical consciousness of the identity of the reproductive representations with the appearances by which they were given.”[826]

In all other respects, however, the above six sections agree (along with I. § 14 C) in holding to a threefold division of mental powers: sensibility, imagination, and apperception. This third stage is thereby marked off sufficiently clearly from the second stage in which pure imagination is wanting, and from the fourth stage in which it is dissolved into a threefold a priori synthesis.

In both I. § 14 C and in III. I the classification which underlies the third stage is explicitly formulated. Their{226} statements harmoniously combine to yield the following tabular statement:

1. The synopsis of the manifold—a priori through sense, i.e. in pure intuition.

2. The synthesis of this manifold—through pure transcendental imagination.

3. The unity of this synthesis—through pure original transcendental apperception.

At this point Vaihinger adds to the above section the earlier passage § 10 T.[827] It is even more definitely than III. γ and III. I transitional to the fourth stage. It must be classed within the third stage, as it holds to the above threefold classification. But it modifies that classification in two respects. First, in that it does not employ the term synopsis, but only speaks of pure intuition as required to yield us a manifold. The term synopsis, as used by Kant, is, however, decidedly misleading.[828] His invariable teaching is that all connection is due to synthesis. By synopsis, therefore, which he certainly does not employ as synonymous with synthesis, can be meant only apprehension of external side-by-sideness. It never signifies anything except apprehension of the lowest possible order. Kant’s omission of the term, therefore, tends to clearness of statement. Secondly, the classification is also modified by the substitution of understanding for the unity of apperception. Apperception is, however, so obscurely treated in all of the above sections, that this cannot be regarded as a vital alteration. What is new in this section, and seems to connect it in a curious and interesting manner with sections in the fourth stage, is its doctrine of

“a manifold of a priori sensibility.” “Space and time contain a manifold of pure a priori intuition.”[829]

That is, in this connection, an entirely new doctrine. In all the previous sections of the deduction (previous in the assumed order of original writing) the manifold supplied through intuition is taken as being empirical, and as consisting of sensations. Kant here also adds that the manifold, “whether given empirically or a priori,”[830] must be synthesised before it can be known.

“The spontaneity of our thought requires that this manifold [of pure a priori intuition] should be run through in a certain manner, taken up, and connected, in order that a knowledge may be formed out of it. This action I call synthesis.”


Fourth Stage.—A 98-104; A 97-8.—As already noted, there are in Kant two persistent but conflicting interpretations of the nature of the synthetic processes exercised by imagination and understanding, the subjectivist and the phenomenalist.[831] Now, on the former view, imagination is simply understanding at work. In other words, imagination is merely the active synthesising side of a faculty whose complementary aspect appears in the logical unity of the concept. From this point of view the transcendental and the empirical factors may be taken as forming a single series. The transcendental and the empirical processes will vary together, some form of transcendental activity corresponding to every fundamental form of empirical activity and vice versa. Such an inference only follows if the subjectivist standpoint be accepted to the exclusion of the phenomenalist point of view. But since Kant constantly alternates between them, and never quite definitely formulates them in their distinction and opposition; since, in fact, they were rather of the nature of obscurely felt tendencies than of formulated standpoints, it is quite intelligible that an inference derived from the one should be drawn even at the very time when the other is being more explicitly developed. This, it would seem, is what actually happened. When we come to consider the evidence derivable from the Reflexionen and Lose Blätter, we shall find support for the view that after January 1780, on the very eve of the publication of the Critique, while the revolutionary, phenomenalist consequences of the Critical hypothesis were becoming clearer to him, he unguardedly allowed the above inference to lead him to recast his previous views in a decidedly subjectivist manner. The view that transcendental imagination has a special and unique activity altogether different in type from any of its empirical processes, namely, the “productive,” is now allowed to drop; and in place of it Kant develops the view that transcendental functions run exactly parallel with the empirical processes of apprehension, reproduction, and recognition. Accordingly, in place of the classification presented in the third stage, we find a new and radically different one introduced into the text, without the least indication that Kant’s standpoint has meantime changed. It is given in A 97:

A. Synopsis of the manifold through sense.

B. Synthesis.

1. Synthesis of apprehension of representations in [inner] intuition.{228}

2. Synthesis of reproduction of representations in imagination.

3. Synthesis of recognition of representations in the concept.

And Kant adds in explanation that “these point to three subjective sources of knowledge which make the understanding itself possible, and which in so doing make all experience possible, in so far as it is an empirical product of the understanding.” What, now, are these three subjective sources of knowledge? They certainly are not those classified in the table of the third stage. A roughly coincides with its first member; consequently B 1 is left without proper correlate. B 2 is altogether different from the previous synthesis of imagination, for in the earlier table transcendental imagination is regarded as being solely productive, never reproductive.[832] It is now asserted to be reproductive—a contradiction of one of his own most emphatic contentions, which can only be accounted for by some such explanation as we are here stating. Nothing is lacking as regards explicitness in the statement of this new position. “...the reproductive synthesis of imagination belongs to the transcendental acts of the soul, and, in reference to it [viz. to the reproductive synthesis], we will call this power too the transcendental power of the imagination.”[833] Lastly, even B 3 does not coincide with the pure apperception of the other table. B 3 is more akin to the recognition which in the third stage is declared to be always empirical. In any case, it is recognition in the concept; and though that may ultimately involve and condition transcendental apperception, it remains, in the manner in which it is here developed by Kant, something very different. But this is a point to which we shall return. There is an added complication, running through this entire stage, which first requires to be disentangled. The transcendental syntheses are declared to condition the pure representations of space and time no less than those of sense-experience.

“This synthesis of apprehension also must be executed a priori, i.e. in reference to representations which are not empirical. For without it we could not have the a priori representations either of space or of time, since these can be generated only through the synthesis of the manifold which sensibility presents in its original receptivity. Thus we have a pure synthesis of apprehension”[834] “...if I draw a line in thought or desire to think of the time from one noon to another, or merely represent to myself a certain number, I must, firstly, apprehend these manifold representations one after{229} the other. But if the preceding representations (the first parts of the line, the antecedent parts of time or the units serially represented) were always to drop out of my thought, and were not reproduced when I advance to those that follow, no complete representation, and none of all the aforementioned thoughts, not even the purest and first basal representations of space and time, could ever arise.”[835]

This, as Vaihinger remarks, is a point of sufficient importance to justify separate treatment. But it is introduced quite incidentally by Kant, and obscures quite as much as it clarifies the main argument.

It is convenient to start with the second synthesis. Kant’s argument is much clearer in regard to it than in regard to the other two. He distinguishes between empirical and transcendental reproduction. Reproduction in ordinary experience, in accordance with the laws of association, is merely empirical. The de facto conformity of appearances to rules is what renders such empirical reproduction possible;

“...otherwise our faculty of empirical imagination would never find any opportunity of action suited to its capacities, and would remain hidden within the mind as a dead, and to us unknown power.”[836]

Kant proceeds to argue, consistently with his doctrine of objective affinity, that empirical reproduction is itself transcendentally conditioned. The form, however, in which this argument is developed is peculiar to the section before us, and is entirely new.

“If we can show that even our purest a priori intuitions yield no knowledge, save in so far as they contain such connection of the manifold as will make possible a thoroughgoing synthesis of reproduction, this synthesis of the imagination must be grounded, prior to all experience, on a priori principles; and since experience necessarily presupposes that appearances can be reproduced, we shall have to assume a pure transcendental synthesis of the imagination as conditioning even the possibility of all experience.”[837]

In the concluding paragraph Kant makes clear that he regards this transcendental activity as being exercised in a twofold manner: in relation to the empirically given manifold as well as in relation to the a priori given manifold. How this transcendental activity is to be distinguished from the empirical is not further explained. I discuss this point below.[838]

The argument of the section on the synthesis of apprehension, to which we may now turn back, suffers from serious{230} ambiguity. It is not clear whether a distinction, analogous to that between empirical and transcendental reproduction, is being made in reference to apprehension. The actual wording of its two last paragraphs would lead to that conclusion. That, however, is a view which would seem to be excluded by the wider context. Kant is dealing with the synthesis of apprehension in inner intuition, i.e. in time. By the fundamental principles of his teaching such intuition must always be transcendental. Empirical apprehension can only concern the data of the special senses. The process of apprehension referred to in the middle paragraph must therefore itself be transcendental.

But it is in dealing with the synthesis of recognition that the argument is most obscure. It is idle attempting to discover any possible distinction between an empirical and a transcendental process of recognition. For the transcendental process here appears as being the consciousness that what we are thinking now is the same as what we thought a moment before; and it is illustrated not by reference to the pure intuitions of space and time, but only by the process of counting. It may be argued that empirical recognition is mediated by transcendental factors—by pure concepts and by apperception. But unless we are to take transcendental recognition as synonymous with transcendental apperception, which Kant’s actual teaching does not seem to justify us in doing, such considerations will not enable us to distinguish two forms of recognition. Apart, however, from this difficulty, there is the further one that the concepts in and through which the recognition is executed are here described as being empirical. The only key that will solve the mystery of this extraordinary section, hopelessly inexplicable when viewed as a single continuous whole, is, it would seem, the theory of Vaihinger, namely,[839] that from the third paragraph onwards (already dealt with as forming the first stage of the deduction) Kant is making use of manuscript which represents the earliest form in which his explanation of the consciousness of objects was developed, with the strange result that this section is a combination of the latest and of the earliest forms of the deduction. While seeking to make out a parallelism between the empirical, conscious activities of imagination and understanding on the one hand, and its transcendental functions on the other, he must have bethought himself of the earlier attempt to explain consciousness of objects through empirical concepts conditioned by transcendental apperception, and so have attempted to expound the third form of synthesis by{231} means of it. As thus extended it involves a distinction between transcendental and empirical apperception, and upon that the discussion, so far as it concerns anything akin to recognition, altogether turns. But there is not the least further mention of recognition itself. As transcendental, it cannot be taken as the equivalent of empirical apperception; and as a synthesis through concepts, can hardly coincide with pure apperception. The title of the section, “the synthesis of recognition in the concept,” is thus no real indication of the astonishing fare prepared for the reader. The doctrine of a threefold synthesis seems to have occurred to Kant on the very eve of the publication of the Critique. The passage expounding it may well have been hurriedly composed, and when unforeseen difficulties accumulated, especially in regard to recognition as a transcendental process, Kant must have resolved simply to close the matter by inserting the older manuscript.

III. Evidence yielded by the “Reflexionen” and “Lose Blätter” in support of the above analysis.

The evidence, derived by Vaihinger from the Reflexionen and Lose Blätter, briefly outlined, is as follows.[840] (1) In the Reflexionen zur Anthropologie relevant passages are few in number, and represent a standpoint very close to that of the 1770 Dissertation. Imagination is treated only as an empirical faculty.[841] Recognition, which is only once mentioned,[842] is also viewed as merely empirical. The understanding is spoken of as the faculty through which objects are thought.[843] The categories are not mentioned, and it is stated that the understanding yields only ideas of reflection. “All knowledge of things is derived, as regards its matter, from sensation—the understanding gives only ideas of reflection.”[844] So far, these Reflexionen would seem to coincide, more or less, with the first stage of the deduction. They contain, however, no reference to transcendental apperception; and are therefore regarded by Vaihinger as representing a still earlier standpoint.

(2) In the Reflexionen zur Kritik der reinen Vernunft there is a very large and valuable body of relevant passages. No. 925 must be of the same date as the letter of 1772 to Herz; it formulates its problem in practically identical terms.[845] Nos. 946-52 and 955 may belong to the period of the first stage. For though the doctrine of the transcendental object as the{232} opposite counterpart of the transcendental subject is not mentioned, the spiritualist view of the self is prominent. In No. 946 it is asserted that the representation of an object is “made by us through freedom.”

“Free actions are already given a priori, namely our own.”[846] “To pass universal objective judgments, and to do so apodictically, reason must be free from subjective grounds of determination. For were it so determined the judgment would be merely accidental, namely in accordance with its subjective cause. Thus reason is conscious a priori of its freedom in objectively necessary judgments in so far as it apprehends them as exclusively grounded through their relation to the object.”[847] “Transcendental freedom is the necessary hypothesis of all rules, and therefore of all employment of the understanding.”[848] “Appearances are representations whereby we are affected. The representation of our free self-activity does not involve affection, and accordingly is not appearance, but apperception.”[849]

It is significant that the categories receive no mention.

Almost all the other Reflexionen would seem to have originated in the period of the second stage of the deduction; but they still betray a strong spiritualist bias.

“Impressions are not yet representations, for they must be related to something else which is an action. Now the reaction of the mind is an action which relates to the impression, and which if taken alone[850] may in its special forms receive the title categories.”[851] “We can know the connection of things in the world only if we produce it through a universal action, and so out of a principle of inner power (aus einem Prinzip der inneren Potestas): substance, ground, combination.”[852]

These Reflexionen recognise only the categories of relation,[853] and must therefore be prior to the twelvefold classification. There is not the least trace of the characteristic doctrines of the third and fourth stages of the deduction, viz. of the transcendental function of the imagination or of a threefold transcendental synthesis. The nature of apprehension is also most obscure. It is frequently equated with apperception.

(3) The Lose Blätter aus Kants Nachlass (Heft I.) contains fragments which also belong to the second stage of the deduction, but which would seem to be of somewhat earlier{233} date than the above Reflexionen.[854] They have interesting points of contact with the first stage. Thus though the phrase transcendental object does not occur in them, the object of knowledge is equated with x, and is regarded in the manner of the first stage as the opposite counterpart of the unity of the self.[855] These fragments belong, however, to the second stage in virtue of their recognition of the a priori categories of relation. There is also here, as is in the Reflexionen, great lack of clearness regarding the nature of apprehension; and there is still no mention of the transcendental faculty of imagination. Fragment 8 is definitely datable. It covers the free spaces of a letter of invitation dated May 20, 1775.[856] Fragment B 12[857] belongs to a different period from the above. This is sufficiently evident from its contents; but fortunately the paper upon which it is written—an official document in the handwriting of the Rector of the Philosophical Faculty of Königsberg—enables us to decide the exact year of its origin. It is dated January 20, 1780. The fragment must therefore be subsequent to that date. Now in it transcendental imagination appears as a third faculty alongside sensibility and understanding, and a distinction is definitely drawn between its empirical and its transcendental employment. The former conditions the synthesis of apprehension; the latter conditions the synthetic unity of apperception. It further distinguishes between reproductive and productive imagination, and ascribes the former exclusively to the empirical imagination. In all these respects it stands in complete agreement with the teaching of the third stage of the deduction. The fact that this fragment is subsequent to January 1780 would seem to prove that even at that late date Kant was struggling with his deduction.[858] But the most interesting of all Vaihinger’s conclusions has still to be mentioned. He points out that at the time when this fragment was composed Kant had not yet developed the doctrine characteristic of the fourth stage, namely, of a threefold transcendental synthesis. Moreover, as he observes, the statement which it explicitly contains, that reproductive imagination is always empirical, is inconsistent with any such doctrine. The teaching of the fourth stage must consequently be ascribed to an even later date.[859]


(4) The Lose Blätter (Heft II.), though almost exclusively devoted to moral and legal questions, contain in E 67[860] a relevant passage which Reicke regards as belonging to the ‘eighties, but which Adickes and Vaihinger agree in dating “shortly before 1781.” On Vaihinger’s view it is a preliminary study for the passages of the fourth stage of the deduction. But such exact dating is not essential to Vaihinger’s argument. It is undoubtedly quite late, and contains the following sentence:

“All representations, whatever their origin, are yet ultimately as representations modifications of inner sense, and their unity must be viewed from this point of view. A spontaneity of synthesis corresponds to their receptivity: either of apprehension as sensations or of reproduction as images (Einbildungen) or of recognition as concepts.”

This is the doctrine from which the deduction of the first edition starts; it was, it would seem, the last to be developed.[861] That we find no trace of it in the Prolegomena, and that it is not only eliminated from the second edition, but is expressly disavowed,[862] would seem to indicate that it had been hastily adopted on the very eve of publication, and that upon reflection Kant had felt constrained definitively to discard it. The threefold synthesis can be verified on the empirical level, but there is no evidence that there exist corresponding transcendental activities.

IV. Connected Statement and Discussion of Kant’s Subjective and Objective Deductions in the First Edition

Such are the varying and conflicting forms in which Kant has presented his deduction of the categories. We may now apply our results to obtain a connected statement of the essentials of his argument. The following exposition, which endeavours to emphasise its main broad features, to distinguish its various steps, and to disentangle its complex and conflicting tendencies, will, I trust, yield to the reader such steady orientation as is necessary in so bewildering a labyrinth.{235} In the meantime I shall take account only of the deductions of the first edition,[863] and from them shall strive to construct the ideal statement to which they severally approximate. Any single relatively consistent and complete deduction that is thus to serve as a standard exposition must, like the root-languages of philology, be typical or archetypal, representing the argument at which Kant aimed; it cannot be one of the alternative expositions which he himself gives. Such reconstruction of an argument which Kant has failed to express in a final and genuinely adequate form must, of course, lie open to all the dangers of arbitrary and personal interpretation. It is an extremely adventurous undertaking, and will have to be carefully guarded by constant reference to Kant’s ipsissima verba. Proof of its historical validity will consist in its capacity to render intelligible Kant’s own departures from it, and in its power of explaining the reasons of his so doing. Its expository value will be in proportion to the assistance which it may afford to the reader in deciphering the actual texts.

Our first task is to make clear the nature of the distinction which Kant draws between the “subjective” and the “objective” deductions. This is a distinction of great importance, and raises issues of a fundamental character. In regard to it students of Kant take widely different views. For it brings to a definite issue many of the chief controversies regarding Critical teaching. Kant has made some very definite statements in regard to it; and one of the opposing schools of interpretation finds its chief and strongest arguments in the words which he employs. But for reasons which will appear in due course, adherence to the letter of the Critique would in this case involve the commentator in great difficulties. We have no option except to adopt the invidious position of maintaining that we may now, after the interval of a hundred years and the labours of so many devoted students, profess to understand Kant better than he understood himself. For such procedure we may indeed cite his own authority.

“Not infrequently, upon comparing the thoughts which an author has expressed in regard to his subject, whether in ordinary conversation or in writing, we find that we can understand him better than he understood himself. As he has not sufficiently determined his concept, he has sometimes spoken, or even thought, in opposition to his own intention.”[864]

Let us, then, consider first the distinction between the two types of deduction in the form in which it is drawn by Kant.{236} In the Preface to the first edition,[865] Kant states that his transcendental deduction of the categories has two sides, and assigns to them the titles subjective and objective.

“This enquiry, which is somewhat deeply grounded, has two sides. The one refers to the objects of pure understanding, and is intended to expound and render intelligible the objective validity of its a priori concepts. It is therefore essential to my purposes. The other seeks to investigate the pure understanding itself, its possibility and the cognitive faculties upon which it rests. Although this latter exposition is of great importance for my chief purpose, it does not form an essential part of it. For the chief question is always simply this,—what and how much can the understanding and Reason know apart from all experience? not—how is the faculty of thought itself possible? The latter is as it were a search for the cause of a given effect; and therefore is of the nature of an hypothesis (though, as I shall show elsewhere, this is not really so); and I would appear to be taking the liberty simply of expressing an opinion, in which case the reader would be free to express a different opinion.[866] For this reason I must forestall the reader’s criticism by pointing out that the objective deduction, with which I am here chiefly concerned, retains its full force even if my subjective deduction should fail to produce that complete conviction for which I hope....”

The subjective deduction seeks to determine the subjective conditions which are required to render knowledge possible, or to use less ambiguous terms the generative processes to whose agency human knowledge is due. It is consequently psychological in character. The objective deduction, on the other hand, is so named because it deals not with psychological processes but with questions of objective validity. It enquires how concepts which are a priori, and which as a priori must be taken to originate in pure reason, can yet be valid of objects. In other words, the objective deduction is logical, or, to use a post-Kantian term, epistemological in character.

It is indeed true, as Kant here insists, that the subjective deduction does not concern itself in any quite direct fashion with the Critical problem—how a priori ideas can relate to objects. “Although of great importance for my chief purpose, it does not form an essential part of it.” This, no doubt, is one reason why Kant omitted it when he revised {237}the Critique for the second edition.[867] None the less it is, as he here says, important; and what exactly that importance amounts to, and whether it is really true that it has such minor importance as to be rightly describable as unessential, is what we have to decide.

Though empirical psychology, in so far as it investigates the temporal development of our experience, is, as Kant very justly claims, entirely distinct in aim and method from the Critical enquiry, the same cannot be said of a psychology which, for convenience, and on the lines of Kant’s own employment of terms, may be named transcendental.[868] For it will deal, not with the temporal development of the concrete and varied aspects of consciousness, but with the more fundamental question of the generative conditions indispensably necessary to consciousness as such, i.e. to consciousness in each and every one of its possible embodiments. In the definition above given of the objective deduction, I have intentionally indicated Kant’s unquestioning conviction that the a priori originates independently of the objects to which it is applied. This independent origin is only describable in mental or psychological terms. The a priori originates from within; it is due to the specific conditions upon which human thinking rests. Now this interpretation of the a priori renders the teaching contained in the subjective deduction much more essential than Kant is himself willing to recognise. The conclusions arrived at may be highly schematic in conception, and extremely conjectural in detail; they are none the less required to supplement the results of the more purely logical analysis. For though in the second edition the sections devoted to the subjective deduction are suppressed, their teaching, and the distinctions which they draw between the different mental processes, continue to be employed in the exposition of the objective deduction, and indeed are presupposed throughout the Critique as a whole. They are indispensably necessary in order to render really definite many of the contentions which the objective deduction itself contains. To eliminate the subjective deduction is not to cut away these presuppositions, but only to leave them in the obscure region of the undefined. They will still continue to influence our mode of formulating and of solving the Critical problem, but will do so as untested and vaguely outlined assumptions, acting as unconscious influences rather than as{238} established principles. For these reasons the omission of the subjective deduction is to be deplored. The explicit statement of the implied psychological conditions is preferable to their employment without prior definition and analysis. The deduction of the second edition rests throughout upon the initial and indispensable assumption, that though connection or synthesis can never be given, it is yet the generative source of all consciousness of order and relation. Factors which are transcendental in the strict or logical meaning of the term rest upon processes that are transcendental in a psychological sense.

This last phrase, ‘transcendental in a psychological sense,’ calls for a word of justification. The synthetic processes generative of experience are not, of course, transcendental in the strict sense. For they are not a priori in the manner of the categories. None the less they are discoverable by the same transcendental method, namely, as being, like the categories, indispensably necessary to the possibility of experience. They differ from the categories in that they are not immanent in experience, constituent of it, and cannot therefore be known in their intrinsic nature. As they fall outside the field of consciousness, they can only be hypothetically postulated. None the less, formal categories and generative processes, definable elements and problematic postulates, alike agree in being conditions sine qua non of experience. And further, in terms of Kant’s presupposed psychology, the latter are the source to which the former are due. There would thus seem to be sufficient justification for extending the term transcendental to cover both; and in so doing we are following the path which Kant himself willingly travelled. For such would seem to have been his unexpressed reasons for ascribing, as he does, the synthetic generative processes to what he himself names transcendental faculties.

This disposes of Kant’s chief reason for refusing to recognise the subjective deduction as a genuine part of the Critical enquiry, namely, the contention upon which he lays such emphasis in the prefaces both of the first and of the second edition,[869] that in transcendental philosophy nothing hypothetical, nothing in any degree dependent upon general reasoning from contingent fact, can have any place. That contention proves untenable even within the domain of his purely logical analyses. The very essence of his transcendental method consists in the establishment of a priori elements through proof of their connection with factual{239} experience. Kant is here revealing how greatly his mind is still biased by the Leibnizian rationalism from which he is breaking away. His a priori cannot establish itself save in virtue of hypothetical reasoning.[870] His transcendental method, rightly understood, does not differ in essential nature from the hypothetical method of the natural sciences; it does so only in the nature of its starting-point, and in the character of the analyses which that starting-point prescribes. And if hypothetical reasoning may be allowed in the establishment of the logical a priori, there is no sufficient reason why it may not also be employed for the determination of dynamical factors. The sole question is as to whether the hypotheses conform to the logical requirements and so raise themselves to a different level from mere opinion and conjecture.[871] As Kant himself says,[872] though his conclusions in the subjective deduction may seem to be hypothetical in the illegitimate sense, they are not really so. From the experience in view of which they are postulated they receive at once the proof of their actuality and the material for their specification.

We may now return to the question of the nature of the two deductions. The complex character of their interrelations may be outlined as follows:

1. Though the subjective deduction is in its later stages coextensive with its objective counterpart, in its earlier stages it moves wholly on what may be called the empirical level. The data which it analyses and the conditions which it postulates are both alike empirical. The objective deduction, on the other hand, deals from start to finish with the a priori.

2. The later stages of the subjective deduction are based upon the results of the objective deduction. The existence and validity of a priori factors having been demonstrated by transcendental, i.e. logical, analysis, the subjective deduction can be extended from the lower to the higher level, and can proceed to establish for the a priori elements what in its earlier stages it has determined for empirical consciousness, namely, the nature of the generative processes which require to be postulated as their ground and origin. When the two deductions are properly distinguished the objective deduction has, therefore, to be placed midway between the initial and the final stages of the subjective deduction.

3. The two deductions concentrate upon different aspects of experience. In the subjective deduction experience is{240} chiefly viewed as a temporal process in which the given falls apart into successive events, which, in and by themselves, are incapable of constituting a unified consciousness. The fundamental characteristic of human experience, from this point of view, is that it is serial in character. Though it is an apprehension of time, it is itself also a process in time. In the objective deduction, on the other hand, the time element is much less prominent. Awareness of objects is the subject-matter to which analysis is chiefly devoted. This difference very naturally follows from the character of the two deductions. The subjective enquiry is mainly interested in the conditions generative of experience, and finds its natural point of departure in the problem by what processes a unified experience is constructed out of a succession of distinct happenings. The objective deduction presents the logical problem of validity in its most striking form, in our awareness of objects; the objective is contrasted with the subjective as being that which is universally and necessarily the same for all observers. Ultimately each of the two deductions must yield an analysis of both types of consciousness—awareness of time and awareness of objects; a priori factors are involved in the former no less than in the latter, and both are conditioned by generative processes. Unfortunately the manner in which this is done in the Critique causes very serious misunderstanding. The problem of the psychological conditions generative of consciousness of objects is raised[873] before the logical analysis of the objective deduction has established the data necessary for its profitable discussion. The corresponding defect in the objective deduction is of a directly opposite character, but is even more unfortunate in its effects. The results obtained from the analysis of our awareness of objects are not, within the limits of the objective deduction, applied in further analysis of our consciousness of time. That is first done, and even then by implication rather than by explicit argument, in the Analytic of Principles. This has the twofold evil consequence, that the relations holding between the two deductions are very greatly obscured, and that the reader is not properly prepared for the important use to which the results of the objective deduction are put in the Analytic of Principles. For it is there assumed—a quite legitimate inference from the objective deduction, but one whose legitimacy Kant has nowhere dwelt upon and explained—that to be conscious of time we must be conscious of it as existing in two distinct orders, subjective and objective. To{241} be conscious of time we must be conscious of objects, and to be conscious of objects we must be able to distinguish between the order of our ideas and the order of the changes (if any) in that which is known by their means.

Thus the two deductions, properly viewed in their full scope, play into one another’s hands. The objective deduction is necessary to complete the analysis of time-consciousness given in the subjective deduction, and the extension of the analysis of object-consciousness to the explanation of time-consciousness is necessary in order to make quite definite and clear the full significance of the conclusions to which the objective enquiry has led.[874]

One last point remains for consideration. Experience is a highly ambiguous term, and to fulfil the rôle assigned to it by Kant’s transcendental method—that of establishing the reality of the conditions of its own possibility—its actuality must lie beyond the sphere of all possible controversy. It must be itself a datum, calling indeed for explanation, but not itself making claims that are in any degree subject to possible challenge. Now if we abstract from all those particularising factors which are irrelevant in this connection, we are left with only three forms of experience—experience of self, experience of objects, and experience of time. The two former are open to question. They may be illusory, as Hume has argued. And as their validity, or rather actuality, calls for establishment, they cannot fulfil the demands which the transcendental method exacts from the experience whose possibility is to yield proof of its discoverable conditions. Consciousness of time, on the other hand, is a fact whose actuality, however problematic in its conditions, and however mysterious in its intrinsic nature, cannot, even by the most metaphysical of subtleties, be in any manner or degree challenged. It is an unquestioned possession of the human mind. Whether time itself is real we are not metaphysically certain, but that, whatever be its reality or unreality, we are conscious of it in the form of change, is beyond all manner of doubt. Consciousness of time is the factual experience, as conditions of whose possibility the a priori {242}factors are transcendentally proved. In so far as they can be shown to be its indispensable conditions, its mere existence proves their reality. And such in effect is the ultimate character of Kant’s proof of the objective validity of the categories. They are proved in that it is shown that only in and through them is consciousness of time possible.

The argument gains immeasurably in clearness when this is recognised;[875] and the deduction of the first edition of the Critique, in spite of its contorted character, remains in my view superior to that of the second edition owing to this more explicit recognition of the temporal aspect of consciousness and to employment of it as the initial starting-point. Analysis at once reveals that though consciousness of time is undeniably actual, it is conditioned in complex ways, and that among the conditions indispensably necessary to its possibility are both consciousness of self and consciousness of an objective order of existence. Starting from the undeniable we are thus brought to the problematic; but owing to the factual character of the starting-point we can substantiate what would otherwise remain open to question.

As this method of formulating Kant’s argument gives greater prominence to the temporal factor than Kant himself does in his statement of the deductions, the reader may very rightly demand further evidence that I am not, by this procedure, setting the deductions in a false or arbitrary perspective. Any statement of Kant’s position in other than his own ipsissima verba is necessarily, in large part, a matter of interpretation, and proof of its correctness must ultimately consist in the success with which it can be applied in unravelling the manifold strands that compose his tortuous and many-sided argument; but the following special considerations may be cited in advance. Those parts of the Critique, such as the chief paragraphs of the subjective deduction and the chapter on Schematism, which are demonstrably late in date of writing, agree in assigning greater prominence to the temporal aspect of experience. This is also true of those numerous passages added in the second edition which deal with inner sense. All of these show an increasing appreciation of the central rôle which time must play in the Critical enquiries. Secondly, proof of the validity of specific categories is given, as we shall find,[876] not in the objective deduction of the Analytic of Concepts, but only in the Analytic of Principles. What Kant gives in the former is only the quite general demonstration that forms of unity, such as are involved in all judgment, are demanded{243} for the possibility of experience. Now when proof of the specific categories does come, in the Analytic of Principles, it is manifestly based on the analysis of time-experience. In the three Analogies, for example, Kant’s demonstration of the objective validity of the categories of relation consists in the proof that they are necessary conditions of the possibility of our time-consciousness. That is to say, the transcendental method of proof, when developed in full detail, in reference to some specific category, agrees with the formulation which I have given of the subjective and objective deductions. In the third place, Kant started from a spiritualist standpoint, akin to that of Leibniz,[877] and only very gradually broke away from the many illegitimate assumptions which it involves. But this original starting-point reveals its persisting influence in the excessive emphasis which Kant continued to lay upon the unity of apperception. He frequently speaks[878] as if it were an ultimate self-justifying principle, by reference to which the validity of all presupposed conditions can be established. But that, as I have already argued, is a legitimate method of procedure only if it has previously been established that self-consciousness is involved in all consciousness, that is, involved even in consciousness of sequence and duration. And as just stated, the deductions of specific categories, given in the Analytic of Principles, fulfil these requirements of complete proof. They start from the time-consciousness, not from apperception.

I shall now summarise these introductory discussions in a brief tabulated outline of the main steps in the argument of the two deductions, and shall add a concluding note upon their interconnection.

Subjective Deduction.—1. Consciousness of time is an experience whose actuality cannot be questioned; by its actuality it will therefore establish the reality of everything that can be proved to be its indispensable condition.

2. Among the conditions indispensably necessary to all consciousness of time are synthetic processes whereby the contents of consciousness, occurring in successive moments, are combined and unified. These processes are processes of apprehension, reproduction, and recognition.

3. Recognition, in turn, is conditioned by self-consciousness.

4. As no consciousness is possible without self-consciousness, the synthetic processes must have completed themselves before such self-consciousness is possible, and consequently are not verifiable by introspection but only by hypothetical construction.{244}

[1, 2, 3, and 4 are steps which can be stated independently of the argument of the objective deduction.]

5. Self-consciousness presupposes consciousness of objects, and consciousness of objects presupposes the synthetic activities of productive imagination whereby the matter of sense is organised in accordance with the categories. These productive activities also are verifiable only by conjectural inference, and only upon their completion can consciousness of any kind make its appearance.

6. Consciousness of self and consciousness of objects thus alike rest upon a complexity of non-phenomenal conditions. For anything that critical analysis can prove to the contrary, consciousness and personality may not be ultimates. They may be resultants due to realities fundamentally different from themselves.

[5 is a conclusion obtained only by means of the argument of the objective deduction. 6 is a further conclusion, first explicitly drawn by Kant in the Dialectic.]

Objective Deduction.—1. The starting-point coincides with that of the subjective deduction. Consciousness of time is an experience by whose actuality we can establish the reality of its indispensable conditions.

2. Among the conditions necessary to all consciousness of time is self-consciousness.

3. Self-consciousness, in turn, is itself conditioned by consciousness of objects.

4. Consciousness of objects is possible only if the categories have validity within the sphere of sense-experience.

5. Conclusion.—The empirical validity of the categories, and consequently the empirical validity of our consciousness alike of the self and of objects, must be granted as a conditio sine qua non of our consciousness of time. They are the indispensable conditions of that fundamental experience.

As above stated,[879] the preliminary stages of the subjective deduction prepare the way for the argument of the objective deduction, while the results obtained by the latter render possible the concluding steps of the former. That is to say, the objective deduction has to be intercalated midway between the opening and the concluding stages of the subjective deduction. It may also be observed that whereas the objective deduction embodies the main positive teaching of the Analytic, in that it establishes the possibility of natural science and of a metaphysics of experience, the subjective deduction is more directly concerned with the subject-matter of the Dialectic, reinforcing, as it does, the more negative{245} consequences which follow from the teaching of the objective deduction—the impossibility of transcendent speculation. It stands in peculiarly close connection with the teaching of the section on the Paralogisms. We may now proceed to a detailed statement of the argument of the two deductions.


In the opening of the subjective deduction Kant is careful to give due prominence to the temporal aspect of our human experience.

“...all the contents of our knowledge are ultimately subject to the formal condition of inner sense, that is, to time, as that wherein they must all be ordered, connected, and brought into relation to one another. This is a general remark which the reader must bear in mind as being a fundamental presupposition of my entire argument.”[880]

Consciousness of time is thus the starting-point of the deduction. Analysis reveals it as highly complex; and the purpose of the deduction is to discover, and, as far as may be possible, to define its various conditions. The argument can best be expounded by reference to a single concrete example—say, our experience of a series of contents, a, b, c, d, e, f, as in succession to one another and as together making up the total six. In order that such an experience may be possible the successive members of the series must be held together simultaneously before the mind. Obviously, if the earlier members dropped out of consciousness before the mind reached f, f could not be apprehended as having followed upon them. There must be a synthesis of apprehension of the successive items.

Such a synthesis of apprehension is, however, only possible through reproduction of the earlier experiences. If when the mind has passed from a to f, f is apprehended as having followed upon a, b, c, d, e, such consciousness is only possible in so far as these earlier contents are reproduced in image. Synthesis of apprehension is conditioned by synthesis of reproduction in imagination.

“But if the preceding representations (the first parts of [a] line, the earlier moments of time or the units represented in sequent order) were always to drop out of my thought, and were not reproduced when I advance to those that follow, no complete representation, and none of all the aforementioned thoughts, not even the purest and first basal representations of space and time, could ever arise.”[881]


In order, however, that the reproduced images may fulfil their function, they must be recognised as standing for or representing contents which the self has just experienced.

“Without the consciousness that what we are thinking is the same as what we thought a moment before, all reproduction in the series of representations would be in vain.”[882]

Each reproduced image would in its present state be a new experience, and would not help in the least towards gaining consciousness of order or number in the succession of our experiences. Recognition is, therefore, a third form of synthesis, indispensably necessary to consciousness of time. But further, the recognition is recognition of a succession as forming a unity or whole, and that unity is always conceptual.

“The word concept (Begriff) might of itself have suggested this remark. For it is this unitary consciousness which unites into a single representation a manifold that has been successively intuited and then subsequently reproduced.”[883] “If in counting I forgot that the units ... have been added to one another in succession, I should never recognise what the sum-total is that is being produced through the successive addition of unit to unit; and so would remain ignorant of the number. For the concept of this number is nothing but the consciousness of this unity of synthesis.”[884]

The synthesis of recognition is thus a synthesis which takes place in and through empirical concepts. In the instance which we have chosen, the empirical concept is that of the number six.

The analysis, however, is not yet complete. Just as reproduction conditions apprehension and both rest on recognition, so in turn recognition presupposes a still further condition, namely, self-consciousness. For it is obvious, once the fact is pointed out, that the recognition of reproduced images as standing for past experiences can only be possible in so far as there is an abiding self which is conscious of its identity throughout the succession. Such an act of recognition is, indeed, merely one particular form or concrete instance of self-consciousness. The unity of the empirical concept in and through which recognition takes place finds its indispensable correlate in the unity of an empirical self. Thus an analysis of our consciousness, even though conducted wholly on the empirical level, that is, without the least reference to the a priori, leads by simple and cogent argument to the{247} conclusion that it is conditioned by complex synthetic processes, and that these syntheses in turn presuppose a unity which finds twofold expression for itself, objectively through a concept and subjectively in self-consciousness.

So far I have stated the argument solely in reference to serial consciousness. Kant renders his argument needlessly complex and diminishes its force by at once extending it so as to cover the connected problem, how we become aware of objects. This occurs in the section on the synthesis of reproduction. An analysis of our consciousness of objects, as distinct from consciousness of the immediately successive, forces us to postulate further empirical conditions. Since the reproductive imagination, to whose agency the apprehension of complex unitary existences is psychologically due, acts through the machinery of association, it presupposes constancy in the apprehended manifold.

“If cinnabar were sometimes red, sometimes black, sometimes light, sometimes heavy, if a man changed sometimes into this and sometimes into that animal form, if the country on the longest day were sometimes covered with fruits, sometimes with ice and snow, my empirical imagination would never even have occasion when representing red colour to bring to mind heavy cinnabar....”[885]

This passage may be compared with the one which occurs in the section on the synthesis of recognition. Our representations, in order to constitute knowledge, must have the unity of some concept; the manifold cannot be apprehended save in so far as this is possible.

“All knowledge demands a concept, though that concept may be quite imperfect or obscure. But a concept is always, as regards its form, something general which serves as a rule. The concept of body, for instance, as the unity of the manifold which is thought through it, serves as a rule to our knowledge of outer appearances.... It necessitates in the perception of something outside us the representation of extension, and therewith the representations of impenetrability, form, etc.”[886]

So far the deduction still moves on the empirical level. When Kant, however, proceeds to insist[887] that this empirical postulate itself rests upon a transcendental condition, the argument is thrown into complete confusion, and the reader is bewildered by the sudden anticipation of one of the most difficult and subtle conclusions of the objective deduction. The same confusion is also caused throughout these sections as a whole by Kant’s description of the various syntheses as{248} being transcendental.[888] They cannot properly be so described. The concepts referred to as unifying the syntheses, and the self-consciousness which is proved to condition the syntheses, are all empirical. They present themselves in concrete form, and presuppose characteristics due to the special contingent nature of the given manifold; as Kant states in so many words in the second edition.

“Whether I can become empirically conscious of the manifold as simultaneous or as successive depends on circumstances or empirical conditions. The empirical unity of consciousness, through association of representations, therefore itself relates to an appearance, and is wholly contingent.”[889]

The argument in these preliminary stages of the subjective deduction, in so far as it is employed to yield proof that all consciousness involves the unity of concepts and the unity of self-consciousness, is independent of any reference to the categories, and consequently to transcendental conditions. In accordance with the plan of exposition above stated, we may now pass to the objective deduction.


The transition from the preliminary stages of the subjective deduction to the objective deduction may be made by further analysis either of the objective unity of empirical concepts or of the subjective unity of empirical self-consciousness. It is the former line which the argument of the first edition follows. Kant is asking what is meant by an object corresponding to our representations,[890] and answers by his objective deduction. He substitutes the empirical for the transcendental object,[891] and in so doing propounds one of the central and most revolutionary tenets of the Critical philosophy. Existence takes a threefold, not a merely dual form. Besides representations and things in themselves, there exist the objects of our representations—the extended world of ordinary{249} experience and of science. Such a threefold distinction is prefigured in the Leibnizian metaphysics, and is more or less native to every philosophy that is genuinely speculative. Kant himself claims Plato as his philosophical progenitor. The originality is not in the bare thesis, but in the fruitful, tenacious, and consistent manner in which it is developed through detailed analysis of our actual experience.

In its first stages the argument largely coincides with the argument of the paragraphs which deal with the transcendental object. When we examine the objective, we find that the primary characteristic distinguishing it from the subjective is that it lays a compulsion upon our minds, constraining us to think about it in a certain way. By an object is meant something which will not allow us to think at haphazard. Cinnabar is an object which constrains us to think it as heavy and red. An object is thus the external source of a necessity to which our thinking has to conform. The two arguments first begin to diverge when Kant sets himself to demonstrate that our consciousness of this external necessity is made possible by categories which originate from within.

For this conclusion Kant prepares the way by an analysis of the second main characteristic constitutive of an object, viz. its unity. This unity is of a twofold nature, involving either the category of substance and attribute or the category of cause and effect. The two categories are ultimately inseparable, but lead us to conceive the object in two distinct modes. When we interpret an object through the a priori concept of substance and attribute, we assert that all the contents of our perceptions of it are capable of being regarded as qualities of one and the same identical substance. No one of its qualities can be incongruent with any other, and all of them together, in their unity, must be expressive of its substantial nature.

The causal interpretation of the object is, however, the more important, and is that which is chiefly emphasised by Kant. It is, indeed, simply a further and more adequate mode of expressing the substantial unity of the object. All the qualities must be causally bound up with one another in such a way that the nature of each is determined by the nature of all the others, and that if any one quality be changed all the others must undergo corresponding alterations. Viewed in this manner, in terms of the category of causality, an object signifies a necessitated combination of interconnected qualities or effects. But since no such form of necessitation can be revealed in the manifold of sense, our consciousness of compulsion cannot originate from without, and must be due to those a priori forms which, though having their{250} source within, control and direct our interpretation of the given. Though the objective compulsion is not itself due to the mind, our consciousness of it has this mental a priori source. The concept of an object consists in the thought of a manifold so determined in its specific order and groupings as to be interpretable in terms of the categories of substance and causality.

But the problem of the deduction proper is not yet raised. On the one hand, Kant has defined what the concept of the objective must be taken as involving, and on the other, has pointed out that since the given as given is an unconnected manifold, any categories through which it may be interpreted must be of independent origin; but it still remains to be proved that the above is a valid as well as a possible mode of construing the given appearances. The categories, as a priori concepts, originate from within. By what right may we assert that they not only relate to an object, but even constitute the very concept of it? Are appearances legitimately interpretable in any such manner? It was, we may believe, in the process of answering this question that Kant came to realise that the objects of our representations must no longer be regarded as things in themselves. For, as he finds, a solution is possible only on the further assumption that the mind is legislating merely for the world of sense-experience, and is making no assertion in regard to the absolutely and independently real. Kant’s method of proof is the transcendental, i.e. he seeks to demonstrate that this interpretation of the given is indispensably necessary as being a sine qua non of its possible apprehension. This is achieved by means of the conclusion already established through the preliminary steps of the subjective deduction, namely, that all consciousness involves self-consciousness. Kant’s proof of the objective validity of the categories consists in showing that only by means of the interpretation of appearances as empirically objective is self-consciousness possible at all.

The self-consciousness of the subjective deduction, in the preliminary form above stated, is, however, itself empirical. Kant, developing on more strictly Critical lines the argument which had accompanied his earlier doctrine of the transcendental object, now proceeds to maintain in what is at once the most fruitful and the most misleading of his tenets, that the ultimate ground of the possibility of consciousness and therefore also of empirical self-consciousness is the transcendental unity of apperception. Such apperception, to use Kant’s ambiguous phraseology, precedes experience as its{251} a priori condition. The interpretation of given appearances through a priori categories is a necessity of consciousness because it is a condition of self-consciousness; and it is a condition of self-consciousness because it alone will account for the transcendental apperception upon which all empirical self-consciousness ultimately depends.

One chief reason why Kant’s deduction is found so baffling and illusive is that it rests upon an interpretation of the unity of apperception which is very definitely drawn, but to which Kant himself gives only the briefest and most condensed expression. I shall therefore take the liberty of restating it in more explicit terms. The true or transcendental self has no content of its own through which it can gain knowledge of itself. It is mere identity, I am I. In other words, self-consciousness is a mere form through which contents that never themselves constitute the self are yet apprehended as being objects to the self. Thus though the self in being conscious of time or duration must be conscious of itself as identical throughout the succession of its experiences, that identity can never be discovered in those experiences; it can only be thought as a condition of them. The continuity of memory, for instance, is not a possible substitute for transcendental apperception. As the subjective deduction demonstrates, self-consciousness conditions memory, and cannot therefore be reduced to or be generated by it.[892] When, however, such considerations are allowed their due weight, the necessity of postulating a transcendental unity becomes only the more evident. Though it can never itself be found among appearances, it is an interpretation which we are none the less compelled to give to appearances.

To summarise before proceeding. We have obtained two important conclusions: first, that all consciousness involves self-consciousness; and secondly, that self-consciousness is a mere form, in terms of which contents that do not constitute the self are apprehended as existing for the self. The first leads up to the second, and the second is equivalent to the assertion that there can be no such thing as a pure self-consciousness, i.e. a consciousness in which the self is aware of itself and of nothing but itself. Self-consciousness, to be{252} possible at all, must at the same time be a consciousness of something that is not-self. Only one further step is now required for the completion of the deduction, namely, proof that this not-self, consciousness of which is necessary to the possibility of self-consciousness, must consist in empirical objects apprehended in terms of the categories. For proof Kant again appeals to the indispensableness of apperception. As no intuitions can enter consciousness which are not capable of being related to the self, they must be so related to one another that, notwithstanding their variety and diversity, the self can still be conscious of itself as identical throughout them all. In other words, no intuition can be related to the self that is incapable of being combined together with all the other intuitions to form a unitary consciousness. I may here quote from the text of the second edition:[893]

“...only in so far as I can grasp the manifold of the representations in one consciousness, do I call them one and all mine. For otherwise I should have as many-coloured and diverse a self as I have representations of which I am conscious to myself.”

Or as it is stated in the first edition:[894]

“We are a priori aware of the complete identity of the self in respect of all representations which belong to our knowledge ... as a necessary condition of the possibility of all representations.”

These are the considerations which lead Kant to entitle the unity of apperception transcendental. He so names it for the reason that, though it is not itself a priori in the manner of the categories, we are yet enabled by its means to demonstrate that the unity which is necessary for possible experience can be securely counted upon in the manifold of all possible representations, and because (as he believed) it also enables us to prove that the forms of such unity are the categories of the understanding.

To the argument supporting this last conclusion Kant does not give the attention which its importance would seem to deserve. He points out that as the given is an unconnected manifold, its unity can be obtained only by synthesis, and that such synthesis must conform to the conditions prescribed by the unity of apperception. That these conditions coincide with the categories he does not, however, attempt to prove. He apparently believes that this has been already established in the metaphysical deduction.[895] The forms of unity demanded by apperception, he feels justified in assuming,{253} are the categories. They may be regarded as expressing the minimum of unity necessary to the possibility of self-consciousness. If sensations cannot be interpreted as the diverse attributes of unitary substances, if events cannot be viewed as arising out of one another, if the entire world in space cannot be conceived as a system of existences reciprocally interdependent, all unity must vanish from experience, and apperception will be utterly impossible.[896]

The successive steps of the total argument of the deduction, as given in the first edition, are therefore as follows: Consciousness of time involves empirical self-consciousness; empirical self-consciousness is conditioned by a transcendental self-consciousness; and such transcendental self-consciousness is itself, in turn, conditioned by consciousness of objects. The argument thus completed becomes the proof of mutual interdependence. Self-consciousness and consciousness of objects, as polar opposites, mutually condition one another. Only through consciousness of both simultaneously can consciousness of either be attained. Only in and through reference to an object can an idea be related to a self, and so be accompanied by that self-consciousness which conditions recognition, and through recognition all the varying forms in which our consciousness can occur. From the point of view, however, of a Critical enquiry apperception is the more important of the two forms of consciousness. For though each is the causa existendi of the other, self-consciousness has the unique distinction of being the causa cognoscendi of the objective and a priori validity of the forms of understanding.

“The synthetic proposition, that all the variety of empirical consciousness must be combined in a single self-consciousness, is the absolutely first and synthetic principle of our thought in general.”[897]

We may at this point consider Kant’s doctrine of “objective affinity.” It excellently enforces the main thesis which he is professing to establish, namely, that the conditions of unitary consciousness are the conditions of all consciousness. The language, however, in which the doctrine is expounded is extremely obscure and difficult; and before commenting upon Kant’s own methods of statement, it seems advisable to paraphrase the argument in a somewhat free manner, and also to defer consideration of the transcendental psychology which Kant has employed in its exposition.[898] Association can subsist only between ideas, both of which have{254} occurred within the same conscious field. Now the fundamental characteristic of consciousness, the very condition of its existing at all, is its unity; and until this has been recognised, there can be no understanding of the associative connection which arises under the conditions which consciousness supplies. To attempt to explain the unity of consciousness through the mechanism of association is to explain an agency in terms of certain of its own effects. It is to explain the fundamental in terms of the derivative, the conditions in terms of what they have themselves made possible. Kant’s argument is therefore as follows. Ideas do not become associated merely by co-existing. They must occur together in a unitary consciousness; and among the conditions necessary to the possibility of association are therefore the conditions of the possibility of experience. Association is transcendentally grounded. So far from accounting for the unity of consciousness, it presupposes the latter as determining the conditions under which alone it can come into play.

“, I ask, is association itself possible?... On my principles the thorough-going affinity of appearances is easily explicable. All possible appearances belong as representations to the totality of a possible self-consciousness. But as this self-consciousness is a transcendental representation, numerical identity is inseparable from it and is a priori certain. For nothing can come to our knowledge save in terms of this original apperception. Now, since this identity must necessarily enter into the synthesis of all the manifold of appearances, so far as the synthesis is to yield empirical knowledge, the appearances are subject to a priori conditions, with which the synthesis of their apprehension must be in complete accordance.... Thus all appearances stand in a thorough-going connection according to necessary laws, and therefore in a transcendental affinity of which the empirical is a mere consequence.”[899]

In other words, representations must exist in consciousness before they can become associated; and they can exist in consciousness only if they are consciously apprehended. But in order to be consciously apprehended, they must conform to the transcendental conditions upon which all consciousness rests; and in being thus apprehended they are set in thoroughgoing unity to one another and to the self. They are apprehended as belonging to an objective order or unity which is the correlate of the unity of self-consciousness. This is what Kant entitles their objective affinity; it is what{255} conditions and makes possible their associative or empirical connection.

This main point is very definitely stated in A 101.

“If we can show that even our purest a priori intuitions yield no knowledge, save in so far as they contain such a connection of the manifold as will make possible a thoroughgoing synthesis of reproduction, this synthesis of the imagination” [which acts through the machinery of association] “must be grounded, prior to all experience, on a priori principles, and since experience necessarily presupposes that appearances can be reproduced, we shall have to assume a pure transcendental synthesis of the imagination” [i.e. such synthesis as is involved in the unity of consciousness] “as conditioning even the possibility of all experience.”[900]

In A 121-2 Kant expresses his position in a more ambiguous manner. He may seem to the reader merely to be arguing that a certain minimum of regularity is necessary in order that representations may be associated, and experience may be possible.[901] But the general tenor of the passage as a whole, and especially its concluding sentences, enforce the stronger, more consistent, thesis.

”[The] subjective and empirical ground of reproduction according to rules is named the association of representations. If this unity of association did not also have an objective ground, which makes it impossible that appearances should be apprehended by the imagination except under the condition of a possible synthetic unity of this apprehension, it would be entirely accidental that appearances should fit into a connected whole of human knowledge. For even though we had the power of associating perceptions, it would remain entirely undetermined and accidental whether they would themselves be associable; and should they not be associable, there might exist a multitude of perceptions, and indeed an entire sensibility, in which much empirical consciousness would arise in my mind, but in a state of separation, and without belonging to one consciousness of myself. That, however, is impossible. For only in so far as I ascribe all perceptions to one consciousness (original apperception), can I say in all perceptions that I am conscious of them. There must therefore be an objective ground (that is, one that can be recognised a priori, antecedently to all empirical laws of the imagination) upon which may rest the possibility, nay the necessity, of a law that extends to all appearances....”

Kant is not merely asserting that the associableness of ideas, and the regularity of connection which that implies, must be postulated as a condition of experience. That would be a mere begging of the issue; the correctness of the{256} postulate would not be independently proved. Kant is really maintaining the much more important thesis, that the unity of experience, i.e. of consciousness, is what makes association possible at all. And since consciousness must be unitary in order to exist, there cannot be any empirical consciousness in which the conditions of association, and therefore of reproduction, are not to be found.

A further misunderstanding is apt to be caused by Kant’s statement that associative affinity rests upon objective affinity. This seems to imply, in the same manner as the passage which we have just considered, that instead of proving that appearances are subject to law and order, he is merely postulating that an abiding ground of such regularity must exist in the noumenal conditions of the sense manifold. But he himself again supplies the needful correction.

“This [objective ground of all association of appearances] can nowhere be found, except in the principle of the unity of apperception in respect of all forms of knowledge which can belong to me. In accordance with this principle all appearances must so enter the mind, or be so apprehended, that they fit together to constitute the unity of apperception. This would be impossible without synthetic unity in their connection, and that unity is therefore also objectively necessary. The objective unity of all empirical consciousness in one consciousness, that of original apperception, is therefore the necessary condition of all (even of all possible) perception; and the affinity of all appearances, near or remote, is a necessary consequence of a synthesis in imagination which is grounded a priori on rules.”[902]

The fundamental characteristic of consciousness is the unified form in which alone it can exist; only when this unity is recognised as indispensably necessary, and therefore as invariably present whenever consciousness exists at all, can the inter-relations of the contents of consciousness be properly defined.

If this main contention of the Critical teaching be accepted, Hume’s associationist standpoint is no longer tenable. Association cannot be taken to be an ultimate and inexplicable property of our mental states. Nor is it a property which can be regarded as belonging to presentations viewed as so many independent existences. It is conditioned by the unity of consciousness, and therefore rests upon the “transcendental” conditions which Critical analysis reveals. Since the unity of consciousness conditions association, it cannot be explained as the outcome and product of the mechanism of association.{257}

In restating the objective deduction in the second edition, Kant has omitted all reference to this doctrine of objective affinity. His reasons for this omission were probably twofold. In the first place, it has been expounded in terms of a transcendental psychology, which, as we shall find, is conjectural in character. And secondly, the phrase “objective affinity” is, as I have already pointed out, decidedly misleading. It seems to imply that Kant is postulating, without independent proof, that noumenal conditions must be such as to supply an orderly manifold of sense data. But though the doctrine of objective affinity is eliminated, its place is to some extent taken[903] by the proof that all apprehension is an act of judgment and therefore involves factors which cannot be reduced to, or explained in terms of, association.

There are a number of points in the deduction of the first edition which call for further explanatory and critical comment. The first of these concerns the somewhat misleading character of the term a priori as applied to the categories. It carries with it rationalistic associations to which the Critical standpoint, properly understood, yields no support. The categories are for Kant of merely de facto nature. They have no intrinsic validity. They are proved only as being the indispensable conditions of what is before the mind as brute fact, namely, conscious experience. By the a priori is meant merely those relational factors which are required to supplement the given manifold in order to constitute our actual consciousness. And, as Kant is careful to point out, the experience, as conditions of which their validity is thus established, is of a highly specific character, resting upon synthesis of a manifold given in space and time. That is to say, their indispensableness is proved only for a consciousness which in these fundamental respects is constituted like our own.[904] And secondly, the validity of the a priori categories, even in our human thinking, is established only in reference to that empirical world which is constructed out of the given manifold in terms of the intuitive forms, space and time. Their validity is a merely phenomenal validity. They are valid of appearances, but not of things in themselves. The a priori is thus doubly de facto: first as a condition of brute fact, namely, the actuality of our human consciousness; and{258} secondly, as conditioning a consciousness whose knowledge is limited to appearances. It is a relative, not an absolute a priori. Acceptance of it does not, therefore, commit us to rationalism in the ordinary meaning of that term. Its credentials are conferred upon it by what is mere fact; it does not represent an order superior to the actual and legislative for it. In other words, it is Critical, not Leibnizian in character. No transcendent metaphysics can be based upon it. In formulating this doctrine of the a priori as yielding objective insight and yet as limited in the sphere of its application, the Critique of Pure Reason marks an epoch in the history of scepticism, no less than in the development of Idealist teaching.

There is one important link in the deduction, as above given, which is hardly calculated to support the conclusions that depend upon it. Kant, as we have already noted,[905] asserts that the categories express the minimum of unity necessary for the possibility of apperception. A contention so essential to the argument calls for the most careful scrutiny and a meticulous exactitude of proof. As a matter of fact, such proof is not to be found in any part of the deductions, whether of the first or of the second editions. It is attempted only in the later sections on the Principles of Understanding, and even there it is developed, in any really satisfactory fashion, only in regard to the categories of causality and reciprocity.[906] This proof, however, as there given, is an argument which in originality, subtlety and force goes far to atone for all shortcomings. It completes the objective deduction by developing in masterly fashion (in spite of the diffuse and ill-arranged character of the text) the central contention for which the deduction stands. But in the transcendental deduction itself, we find only such an argument—if it may be called an argument—as follows from the identification of apperception with understanding.

“The unity of apperception, in relation to the synthesis of imagination, is the understanding.... In understanding there are pure a priori forms of knowledge which contain the necessary unity of pure synthesis of imagination in respect of all possible appearances. But these are the categories, i.e. pure concepts of understanding.”[907]

The point is again merely assumed in A 125-6. So also in A 126:

“Although through experience we learn many laws, these are only special determinations of still higher laws, of which the highest,{259} under which all others stand, originate a priori in the understanding itself....”[908]

Again in A 129 it is argued that as we prescribe a priori rules to which all experience must conform, those rules cannot be derived from experience, but must precede and condition it, and can do so only as originating from ourselves (aus uns selbst).

”[They] precede all knowledge of the object as [their] intellectual form, and constitute a formal a priori knowledge of all objects in so far as they are thought (categories).”

But this is only to repeat that such forms of unity as are necessary to self-consciousness must be realised in all synthesis. It is no sufficient proof that those forms of relation coincide with the categories. As we shall find in considering the deduction of the second edition, Kant to some extent came to recognise the existence of this gap in his argument and sought to supply the missing steps. But his method of so doing still ultimately consists in an appeal to the results of the metaphysical deduction, and therefore rests upon his untenable belief in the adequacy of formal logic. It fails to obviate the objection in any satisfactory manner.

As regards the negative aspect of the conclusion reached—that the validity of the categories is established only for appearances—Kant maintains that this is a necessary corollary of their validity being a priori. That things in themselves must conform to the conditions demanded by the nature of our self-consciousness is altogether impossible of proof. Even granting, what is indeed quite possible, that things in themselves embody the pure forms of understanding, we still cannot have any ground for maintaining that they must do so of necessity and will be found to do so universally. For even if we could directly experience things in themselves, and apprehend them as conforming to the categories, such conformity would still be known only as contingent. But when it is recognised that nature consists for us of nothing but appearances, existing only in the mode in which they are experienced, and therefore as necessarily conforming to the conditions under which experience is alone possible, the paradoxical aspect of the apriority ascribed to the categories at once vanishes. Proof of their a priori validity presupposes the phenomenal character of the objects to which they apply. They can be proved to be universal and necessarily valid of objects only in so far as it can be shown that they have{260} antecedently conditioned and constituted them. The sole sufficient reason for asserting them to be universally valid throughout experience is that they are indispensably necessary for rendering it possible.[909] The transcendental method of proof, i.e. proof by reference to the very possibility of experience, is for this reason, as Kant so justly emphasises, the sole type of argument capable of fulfilling the demands which have to be met. It presupposes, and itself enforces, the truth of the fundamental Critical distinction between appearances and things in themselves.

Kant entitles the unity of apperception original (ursprünglich);[910] and we may now consider how far and in what sense this title is applicable.[911] From the point of view of method there is the same justification for employing the term ‘original’ as for entitling the unity of apperception transcendental.[912] Self-consciousness is more fundamental or original than consciousness of objects, in so far as[913] it is only from the subjective standpoint which it represents that the objective deduction can demonstrate the necessity of synthesis, and the empirical validity of the pure forms of understanding. It is as a condition of the possibility of self-consciousness that the objective employment of the categories is proved to be legitimate. In the development of the deduction self-consciousness is, therefore, more original than consciousness of objects. Kant’s employment of the term is, however, extremely misleading. For it would seem to imply that the self has been proved to be original or ultimate in an ontological sense, as if it preceded experience, and through its antecedent reality rendered objective experience possible of achievement. Such a view is undoubtedly reinforced by Kant’s transformation of apperception into a faculty—das Radicalvermögen aller unsrer Erkenntniss[914]—and his consequent identification of it with the understanding.[915] It then seems as if he were maintaining that the transcendental ego is ultimate and is independent of all conditions, and that to its synthetic activities the various forms of objective consciousness are due.[916]

This unfortunate phraseology is directly traceable to the spiritualistic or Leibnizian character of Kant’s earlier standpoint. In the Dissertation the self is viewed as an ultimate{261} and unconditioned existence, antecedent to experience and creatively generative of it. We have already noted that a somewhat similar view is presented in the Critique in those paragraphs which Vaihinger identifies as embodying the earliest stage in the development of the argument of the deduction. The self is there described as coming to consciousness of its permanence through reflection upon the constancy of its own synthetic activities. Our consciousness of a transcendental object, and even the possibility of the empirical concepts through which such consciousness is, in these paragraphs, supposed to be mediated, are traced to this same source. To the last this initial excess of emphasis upon the unity of apperception remained characteristic of Kant’s Critical teaching; and though in the later statements of his theory, its powers and prerogatives were very greatly diminished, it still continued to play a somewhat exaggerated rôle. The early spiritualistic views were embodied in a terminology which he continued to employ; and unless the altered meaning of his terms is recognised and allowed for, misunderstanding is bound to result. The terms, having been forged under the influence of the older views, are but ill adapted to the newer teaching which they are employed to formulate.

There was also a second influence at work. When Kant was constrained in the light of his new and unexpected results to recognise his older views as lacking in theoretical justification, he still held to them in his own personal thinking. For there is ample evidence that they continued to represent his Privatmeinungen.[917]

Only, therefore, when these misleading influences, verbal, expository, and personal, are discounted, do the results of the deduction appear in their true proportions. Kant’s Critical philosophy does not profess to prove that it is self-consciousness, or apperception, or a transcendental ego, or anything describable in kindred terms, which ultimately renders experience possible. The most that we can legitimately postulate, as noumenally conditioning experience, are “syntheses” (themselves, in their generative character, not definable)[918] in accordance with the categories. For only upon the completion of such syntheses do consciousness of self and consciousness of objects come to exist. Consciousness of objects does, indeed, according to the argument of the deduction, involve consciousness of self; self-consciousness is the form of all consciousness. But, by the same argument, it is equally true{262} that only in and through consciousness of objects is any self-consciousness possible at all. Consciousness of self and consciousness of objects mutually condition one another. Only through consciousness of both simultaneously can consciousness of either be attained. Self-consciousness is not demonstrably in itself any more ultimate or original than is consciousness of objects. Both alike are forms of experience which are conditioned in complex ways. Upon the question as to whether or not there is any such thing as abiding personality, the transcendental deduction casts no direct light. Indeed consciousness of self, as the more inclusive and complex form of awareness, may perhaps be regarded as pointing to a greater variety of contributory and generative conditions.

Unfortunately Kant, for the reasons just stated, has not sufficiently emphasised this more negative, or rather noncommittal, aspect of the results of the deduction. But when later in the chapter on the Paralogisms he is brought face to face with the issue, and has occasion to pronounce upon the question, he speaks with no uncertain voice. In the theoretical sphere there is, he declares, no sufficient proof of the spirituality, or unitary and ultimate character, of the self. Like everything else the unity of apperception must be noumenally conditioned, but it cannot be shown that in itself, as self-consciousness or apperception, it represents any noumenal reality. It may be a resultant, resting upon, and due to, a complexity of generative conditions; and these conditions may be fundamentally different in character from itself. They may, for all that we can prove to the contrary, be of a non-conscious and non-personal nature. There is nothing in our cognitive experience, and no result of the Critical analysis of it, which is inconsistent with such a possibility.[919] Those commentators, such as Cohen, Caird, and Watson, who more or less follow Hegel in his criticism of Kant’s procedure, give an interpretation of the transcendental deduction which makes it inconsistent with the sceptical conclusions which the Critique as a whole is made by its author to support. Unbiassed study of the Analytic, even if taken by itself in independence of the Dialectic, does not favour such a view. The argument of the transcendental deduction itself justifies no more than Kant is willing to allow in his discussion of the nature of the self in the section on the Paralogisms. It may, indeed, as Caird has so forcibly shown in his massive work upon the Critical philosophy, be developed upon Hegelian lines, but {263}only through a process of essential reconstruction which departs very far from many of Kant’s most cherished tenets, and which does so in a spirit that radically conflicts with that which dominates the Critique as a whole.


The reader will have noted that several of the factors in Kant’s exposition have so far been entirely ignored. The time has now come for reckoning with them. They constitute, in my view, the later stages of the subjective deduction. That is to say, they refer to the transcendental generative powers which Kant, on the strength of the results obtained in the more objective enquiry, feels justified in postulating. Separate consideration of them tends to clearness of statement. Kant’s constant alternation between the logical and the dynamical standpoints is one of the many causes of the obscurity in his argument. In this connection we shall also find opportunity to discuss the fundamental conflict, to which I have already had occasion to refer, between the subjectivist and the phenomenalist modes of developing the Critical standpoint.

The conclusions arrived at in the objective deduction compelled Kant to revise his previous psychological views. Hitherto he had held to the Leibnizian theory that a priori concepts are obtained by reflection upon the mind’s native and fundamental modes of action. In the Dissertation he carefully distinguishes between the logical and the real employment of the understanding. Through the former empirical concepts are derived from concrete experience. Through the latter pure concepts are creatively generated. Logical and real thinking agree, however, Kant there argues, in being activities of the conscious mind. Both can be apprehended and adequately determined through the revealing power of reflective consciousness. Such a standpoint is no longer tenable for Kant. Now that he has shown that the consciousness of self and the consciousness of objects mutually condition one another, and that until both are attained neither is possible, he can no longer regard the mind as even possibly conscious of the activities whereby experience is brought about. The activities generative of consciousness have to be recognised as themselves falling outside it. Not even in its penumbra, through some vague form of apprehension, can they be detected. Only the finished products of such activities, not the activities themselves, can be presented to consciousness; and only by general reasoning,{264} inferential of agencies that lie outside the conscious field, can we hope to determine them.

Now Kant appears to have been unwilling to regard the ‘understanding’ as ever unconscious of its activities. Why he was unwilling, it does not seem possible to explain; at most his rationalist leanings and Wolffian training may be cited as contributing causes. To the end he continued to speak of the understanding as the faculty whereby the a priori is brought to consciousness. In order to develop the distinctions demanded by the new Critical attitude, he had therefore to introduce a new faculty, capable of taking over the activities which have to be recognised as non-conscious. For this purpose he selected the imagination, giving to it the special title, productive imagination. The empirical reproductive processes hitherto alone recognised by psychologists are not, he declares, exhaustive of the nature of the imagination. It is also capable of transcendental activity, and upon this the “objective affinity” of appearances and the resulting possibility of their empirical apprehension is made to rest. The productive imagination is also viewed as rendering possible the understanding, that is, the conscious apprehension of the a priori as an element embedded in objective experience. Such apprehension is possible because in the pre-conscious elaboration of the given manifold the productive imagination has conformed to those a priori principles which the understanding demands for the possibility of its own exercise in conscious apprehension. Productive imagination acts in the manner required to yield experiences which are capable of relation to the unity of self-consciousness, i.e. of being found to conform to the unity of the categories. Why it should act in this manner cannot be explained; but it is none the less, on Critical principles, a legitimate assumption, since only in so far as it does so can experience, which de facto exists, be possible in any form. As a condition sine qua non of actual and possible experience, the existence of such a faculty is, Kant argues, a legitimate inference from the results of the transcendental deduction.

Though Kant’s insistence upon the conscious character of understanding compels him to distinguish between it and the imagination, he has also to recognise their kinship. If imagination can never act save in conformity with the a priori forms of understanding, some reason must exist for their harmony. This twofold necessity of at once distinguishing and connecting them is the cause of the hesitating and extremely variable account which in both editions of the Critique is given of their relation. In several passages the{265} understanding is spoken of as simply imagination which has attained to consciousness of its activities.[920] Elsewhere he explicitly states that they are distinct and separate. From this second point of view Kant regards imagination as mediating between sense and understanding, and, though reducible to neither, akin to both.

Only on one point is Kant clear and definite, namely, that it is to productive imagination that the generation of unified experience is primarily due. In it something of the fruitful and inexhaustible character of noumenal reality is traceable. Doubtless one chief reason for his choice of the title imagination is the creative character which in popular thought has always been regarded as its essential feature. As Kant, speaking of schematism, which is a process executed by the imagination, states in A 141: “This schematism ... is an art (Kunst) concealed in the depths of the human soul.”[921] This description may perhaps be interpreted in the light of Kant’s account of the creative character of artistic genius in the Critique of Judgment, for there also imagination figures as the truly originative or creative faculty of the human spirit. To its noumenal character we may also trace its capacity of combining those factors of sense and understanding which in the realm of appearance remain persistently opposed.[922] Imagination differs from the understanding chiefly in that it is at once more comprehensive and also more truly creative. It supplements the functional forms with a sensuous content, and applies them dynamically in the generation of experience.

The schemata, which the productive imagination is supposed to construct, are those generalised forms of temporal and spatial existence in which alone the unity of experience necessary to apperception can be realised. They are

“pure (without admixture of anything empirical), and yet are in one aspect intellectual and in another sensuous.”[923]

Or as Kant describes the process in the chapter before us:[924]

“We name the synthesis of the manifold in imagination transcendental, if without distinction of intuitions it is directed exclusively to the a priori combination of the manifold; and the unity of this synthesis is entitled transcendental, if it is represented as a priori necessary in relation to the original unity of apperception.{266} As this unity of apperception conditions the possibility of all knowledge, the transcendental unity of the synthesis of imagination is the pure form of all possible knowledge. Hence, through it all objects of possible experience must be represented a priori.”

The schemata, thus transcendentally generated, are represented by Kant as limiting and controlling the empirical processes of apprehension, reproduction, and recognition. As no experience is attainable save in terms of the schemata, they enable us to determine, on a priori grounds, the degree of constancy and regularity that can be securely counted upon in all experience. This is Kant’s psychological explanation of what he has entitled “objective affinity.”[925] The empirical ground of reproduction is the association of ideas; its transcendental ground is an objective affinity which is “a necessary consequence of a synthesis in imagination, grounded a priori on rules.”[926]

”[The] subjective and empirical ground of reproduction according to rules is named the association of representations. If this unity of association did not also have an objective ground, which makes it impossible that appearances should be apprehended by the imagination except under the condition of a possible synthetic unity of this apprehension, it would be entirely accidental that appearances should fit into a connected whole of human knowledge.... There might exist a multitude of perceptions, and indeed an entire sensibility, in which much empirical consciousness would arise in my mind, but in a state of separation, and without belonging to one consciousness of myself. That, however, is impossible.” [As the subjective and objective deductions have demonstrated, where there is no self-consciousness there is no consciousness of any kind.] “There must therefore be an objective ground (that is, one that can be determined a priori, antecedently to all empirical laws of the imagination) upon which may rest the possibility, nay, the necessity of a law that extends to all appearances—the law, namely, that all appearances must be regarded as data of the senses which are associable in themselves and subject to general rules of universal connection in their reproduction. This objective ground of all association of appearances I entitle their affinity.... The objective unity of all empirical consciousness in one consciousness, that of original apperception, is the necessary condition of all possible perception; and the affinity of all appearances, near or remote, is a necessary consequence of a synthesis in imagination which is grounded a priori on rules.”[927]

This part of Kant’s teaching is apt to seem more obscure than it is. For the reader is not unnaturally disinclined to{267} accept it in the very literal sense in which it is stated. That Kant means, however, exactly what he says, appears from the further consequence which he himself not only recognises as necessary, but insists upon as valid. The doctrine of objective affinity culminates in the conclusion[928] that it is “we ourselves who introduce into the appearances that order and regularity which we name nature.” The “we ourselves” refers to the mind in the transcendental activities of the productive imagination. The conscious processes of apprehension, reproduction, and recognition necessarily conform to schemata, non-consciously generated, which express the combined a priori conditions of intuition and understanding required for unitary consciousness.

Many points in this strange doctrine call for consideration. It rests, in the first place, upon the assumption of a hard and fast distinction, very difficult of acceptance, between transcendental and empirical activities of the mind. Secondly, Kant’s assertion, that the empirical manifolds can be relied upon to supply a satisfactory content for the schemata, calls for more adequate justification than he himself adduces. It is upon independent reality that the fixity of empirical co-existences and sequences depends. Is not Kant practically assuming a pre-established harmony in asserting that as the mind creates the form of nature it can legislate a priori for all possible experience?

As regards the first assumption Kant would seem to have been influenced by the ambiguities of the term transcendental. It means, as we have already noted,[929] either the science of the a priori, or the a priori itself, or the conditions which render experience possible. Even the two latter meanings by no means coincide. The conditions of the possibility of experience are not in all cases a priori. The manifold of outer sense is as indispensable a precondition of experience as are the forms of understanding, and yet is not a priori in any valid sense of that term. It does not, therefore, follow that because the activities of productive imagination “transcendentally” condition experience, they must themselves be a priori, and must, as Kant also maintains,[930] deal with a pure a priori manifold. Further, the separation between transcendental and empirical activities of the mind must defeat the very purpose for which the productive imagination is postulated, namely, in order to account for the generation of a complex consciousness in which no one element can temporally precede any of the others. If the productive imagination generates only schemata, it will not{268} account for that complex experience in which consciousness of self and consciousness of objects are indissolubly united. The introduction of the productive imagination seems at first sight to promise recognition of the dynamical aspect of our temporally sequent experience, and of that aspect in which as appearance it refers us beyond itself to non-experienced conditions. As employed, however, in the doctrines of schematism and of objective affinity, the imagination exhibits a formalism hardly less extreme than that of the understanding whose shortcomings it is supposed to make good.

In his second assumption Kant, as so often in the Critique, is allowing his old-time rationalistic leanings to influence him in underestimating the large part which the purely empirical must always occupy in human experience, and in exaggerating the scope of the inferences which can be drawn from the presence of the formal, relational factors. But this is a point which we are not yet in a position to discuss.[931]

Fortunately, if Vaihinger’s theory be accepted,[932] section A 98-104 enables us to follow the movement of Kant’s mind in the interval between the formulating of the doctrine of productive imagination and the publication of the Critique. He himself would seem to have recognised the unsatisfactoriness of dividing up the total conditions of experience into transcendental activities that issue in schemata, and supplementary empirical processes which transform them into concrete, specific consciousness. The alternative theory which he proceeds to propound is at first sight much more satisfactory. It consists in duplicating each of the various empirical processes with a transcendental faculty. There are, he now declares, three transcendental powers—a transcendental faculty of apprehension, a transcendental faculty of reproduction (=imagination), and a transcendental faculty of recognition. Thus Kant’s previous view that transcendental imagination has a special and unique activity, namely, the productive, altogether different in type from any of its empirical processes, is now allowed to drop; in place of it Kant develops the view that the transcendental functions run exactly parallel with the empirical processes.[933] But though such a position may at first seem more promising than that which it displaces, it soon reveals its unsatisfactoriness. The two types of mental activity, transcendental and empirical, no longer, indeed, fall apart; but the difficulty now arises of distinguishing in apprehension, reproduction, and recognition{269} any genuinely transcendental aspect.[934] Apprehension, reproduction, and recognition are so essentially conscious processes that to view them as also transcendental does not seem helpful. They contain elements that are transcendental in the logical sense, but cannot be shown to presuppose in any analogous fashion mental powers that are transcendental in the dynamical sense. This is especially evident in regard to recognition, which is described as being “the consciousness that what we are thinking is the same as what we thought a moment before.” In dealing with apprehension and reproduction the only real difference which Kant is able to suggest, as existing between their transcendental and their empirical activities, is that the former synthesise the pure a priori manifolds of space and time, and the latter the contingent manifold of sense. But even this unsatisfactory distinction he does not attempt to apply in the case of recognition. Nor can we hold that by the transcendental synthesis of recognition Kant means transcendental apperception. That is, of course, the suggestion which at once occurs to the reader. But however possible it might be to inject such a meaning into kindred passages elsewhere, it cannot be made to fit the context of this particular section.

Vaihinger’s theory seems to be the only thread which will guide us through this labyrinth. Kant, on the eve of the publication of the Critique, recognising the unsatisfactoriness of his hard and fast separation of transcendental from empirical processes, adopted the view that some form of transcendental activity corresponds to every fundamental form of empirical activity and vice versa. Hastily developing this theory, he incorporated it into the Critique alongside his older doctrine. It does not, however, reappear in the Prolegomena, and its teaching is explicitly withdrawn in the second edition of the Critique. Its plausibility had entrapped him into its temporary adoption, but the defects which it very soon revealed speedily led him to reject it.

One feature of great significance calls for special notice. The breakdown of this doctrine of a threefold transcendental synthesis did not, as might naturally have been expected from what is stated in the prefaces to the Critique regarding the unessential and seemingly conjectural character of the subjective deduction, lead Kant to despair of developing a transcendental psychology. Though in the second edition he cuts away the sections containing the earlier stages of the subjective deduction,[935] and in recasting the other sections{270} gives greater prominence to the more purely logical analyses, the older doctrine of productive imagination is reinstated in full force,[936] and is again developed in[937] connection with the doctrine of pure a priori manifolds. Evidently, therefore, Kant was not disheartened by the various difficulties which lie in the path of a transcendental psychology, and it seems reasonable to conclude that there were powerful reasons inclining him to its retention. I shall now attempt, to the best of my powers, to explain—the task is a delicate and difficult one—what we may believe these reasons to have been.[938]


A wider set of considerations than we have yet taken into account must be borne in mind if certain broader and really vital implications of Kant’s enquiry are to be properly viewed. The self has a twofold aspect. It is at once animal in its conditions and potentially universal in its powers of apprehension. Though man’s natural existence is that of an animal organism, he can have consciousness of the spatial world out of which his organism has arisen, and of the wider periods within which his transitory existence falls. Ultimately such consciousness would seem to connect man cognitively with reality as a whole. Now it is to this universal or absolutist aspect of our consciousness, to its transcendence of the embodied and separate self, that Kant is seeking to do justice in his transcendental deductions, especially in his doctrine of the transcendental unity of apperception. For he views that apperception as conditioned by, and the correlate of, the consciousness of objectivity. It involves the consciousness of a single cosmical time and of a single cosmical space within which all events fall and within which they form a whole of causally interdependent existences. That is why he names it the objective unity of apperception. It is that aspect in which the self correlates with a wider reality, and through which it stands in fundamental contrast to the merely subjective states and to the individual conditions of its animal existence. The transcendental self, so far from being identical with the empirical self, would seem to be of directly opposite nature. The one would seem to point{271} beyond the realm of appearance, the other to be in its existence merely natural. The fact that they are inextricably bound up with one another, and co-operate in rendering experience possible, only makes the more indispensable the duty of recognising their differing characters. Even should they prove to be inseparable aspects of sense-experience, without metaphysical implications, that would not obviate the necessity of clearly distinguishing them. The distinction remains, whatever explanation may be adopted of its speculative or other significance.

Now obviously in so fundamental an enquiry, dealing as it does with the most complicated and difficult problem in the entire field of metaphysics, no brief and compendious answer can cover all the various considerations which are relevant and determining. The problem of the deduction being what it is, the section dealing with it can hardly fail to be the most difficult portion of the whole Critique. The conclusions at which it arrives rest not merely upon the argument which it contains but also upon the results more or less independently reached in the other sections. The doctrine of the empirical object as appearance requires for its development the various discussions contained in the Aesthetic, in the sections on Inner Sense and on the Refutation of Idealism, in the chapters on Phenomena and Noumena and on the Antinomies. The metaphysical consequences and implications of Kant’s teaching in regard to the transcendental unity of apperception are first revealed in the chapter on the Paralogisms. The view taken of productive imagination is expanded in the section on Schematism. In a word, the whole antecedent teaching of the Critique is focussed, and the entire subsequent development of the Critical doctrine is anticipated, in this brief chapter.

But there are, of course, additional causes of the difficulty and obscurity of the argument. One such cause has already been noted, namely, that the Critique is not a unitary work, developed from a previously thought-out standpoint, but in large part consists of manuscripts of very various dates, artificially pieced together by the addition of connecting links. In no part of the Critique is this so obvious as in the Analytic of Concepts. Until this is recognised all attempts to interpret the text in any impersonal fashion are doomed to failure. For this reason I have prefaced our discussion by a statement of Vaihinger’s analysis. No one who can accept it is any longer in danger of underestimating this particular cause of the obscurity of Kant’s deduction.

But the chief reason is one to which I have thus far made{272} only passing reference, and to which we may now give the attention which its importance demands, namely, the tentative and experimental character of Kant’s own final solutions. The arguments of the deduction are only intelligible if viewed as an expression of the conflicting tendencies to which Kant’s thought remained subject. He sought to allow due weight to each of the divergent aspects of the experience which he was analysing, and in so doing proceeded, as it would seem, simultaneously along the parallel lines of what appeared to be the possible, alternative methods of explanation. And to the end these opposing tendencies continued side by side, to the confusion of those readers who seek for a single unified teaching, but to the great illumination of those who are looking to Kant, not for clear-cut or final solutions, but for helpful analysis and for partial disentanglement of the complicated issues which go to constitute these baffling problems.

The two chief tendencies which thus conflicted in Kant’s mind may be named the subjectivist and the phenomenalist respectively. This conflict remained, so to speak, underground, influencing the argument at every point, but seldom itself becoming the subject of direct discussion. As we shall find, it caused Kant to develop a twofold view of inner sense, of causality, of the object of knowledge, and of the unity of apperception. One of the few sections in the Critique where it seems on the point of emerging into clear consciousness is the section, added in the second edition, on the Refutation of Idealism. But this section owes its origin to polemical causes. It represents a position peculiar to the maturer portions of the Analytic; the rest of the Critique is not rewritten so as to harmonise with it, or to develop the consequences which consistent holding to it must involve.

I shall use the term subjectivism (and its equivalent subjective idealism) in the wide sense[939] which makes it applicable to the teaching of Descartes and Locke, of Leibniz and Wolff, no less than to that of Berkeley and Hume. A common element in all these philosophies is the belief that subjective or mental states, “ideas” in the Lockean sense, are the objects of consciousness, and further are the sole possible objects of which it can have any direct or immediate awareness. Knowledge is viewed as a process entirely internal to the individual mind, and as carrying us further only in virtue of some additional supervening process, inferential, conjectural, or instinctive. This subjectivism also tends to combine with a view of consciousness as an ultimate self-revealing property{273} of a merely individual existence.[940] For Descartes consciousness is the very essence, both of the mind and of the self. It is indeed asserted to be exhaustive of the nature of both. Though the self is described as possessing a faculty of will as well as a power of thinking, all its activities are taken as being disclosed to the mind through the revealing power of its fundamental attribute. The individual mind is thus viewed as an existence in which everything takes place in the open light of an all-pervasive consciousness. Leibniz, it is true, taught the existence of subconscious perceptions, and so far may seem to have anticipated Kant’s recognition of non-conscious processes; but as formulated by Leibniz that doctrine has the defect which frequently vitiates its modern counterpart, namely that it represents the subconscious as analogous in nature to the conscious, and as differing from it only in the accidental features of intensity and clearness, or through temporary lack of control over the machinery of reproductive association. The subconscious, as thus represented, merely enlarges the private content of the individual mind; it in no respect transcends it.

The genuinely Critical view of the generative conditions of experience is radically different from this Leibnizian doctrine of petites perceptions. It connects rather with Leibniz’s mode of conceiving the origin of a priori concepts. But even that teaching it restates in such fashion as to free it from subjectivist implications. Leibniz’s contention that the mind is conscious of its fundamental activities, and that it is by reflection upon them that it gains all ultimate a priori concepts, is no longer tenable in view of the conclusions established in the objective deduction. Mental processes, in so far as they are generative of experience, must fall outside the field of consciousness, and as activities dynamically creative cannot be of the nature of ideas or contents. They are not subconscious ideas but non-conscious processes. They are not the submerged content of experience, but its conditioning grounds. Their most significant characteristic has still, however, to be mentioned. They must no longer be interpreted in subjectivist terms, as originating in the separate existence of an individual self. In conditioning experience they generate the only self for which experience can vouch, and consequently, in the absence of full and independent proof, must not be conceived as individually circumscribed.{274} The problem of knowledge, properly conceived, is no longer how consciousness, individually conditioned, can lead us beyond its own bounds, but what a consciousness, which is at once consciousness of objects and also consciousness of a self, must imply for its possibility. Kant thus obtains what is an almost invariable concomitant of scientific and philosophical advance, namely a more correct and scientific formulation of the problem to be solved. The older formulation assumes the truth of the subjectivist standpoint; the Critical problem, when thus stated, is at least free from preconceptions of that particular brand. Assumptions which hitherto had been quite unconsciously held, or else, if reflected upon, had been regarded as axiomatic and self-evident, are now brought within the field of investigation. Kant thereby achieves a veritable revolution; and with it many of the most far-reaching consequences of the Critical teaching are closely bound up.

This new standpoint, in contrast to subjective idealism, may be named Critical, or to employ the term which Kant himself applies both to his transcendental deduction and to the unity of apperception, objective idealism. But as the distinction between appearance and reality is no less fundamental to the Critical attitude, we shall perhaps be less likely to be misunderstood, or to seem to be identifying Kant’s standpoint with the very different teaching of Hegel, if by preference we employ the title phenomenalism.

In the transcendental deduction Kant, as above noted, is seeking to do justice to the universal or absolutist aspect of our consciousness, to its transcendence of the embodied and separate self. The unity of apperception is entitled objective, because it is regarded as the counterpart of a single cosmical time and of a single cosmical space within which all events fall. Its objects are not mental states peculiar to itself, nor even ideal contents numerically distinct from those in other minds. It looks out upon a common world of genuinely independent existence. In developing this position Kant is constrained to revise and indeed completely to recast his previous views both as to the nature of the synthetic processes, through which experience is constructed, and of the given manifold, upon which they are supposed to act. From the subjectivist point of view the synthetic activities consist of the various cognitive processes of the individual mind, and the given manifold consists of the sensations aroused by material bodies acting upon the special senses. From the objective or phenomenalist standpoint the synthetic{275} processes are of a noumenal character, and the given manifold is similarly viewed as being due to noumenal agencies acting, not upon the sense-organs, which as appearances are themselves noumenally conditioned, but upon what may be called “outer sense.” These distinctions may first be made clear.

Sensations, Kant holds, have a twofold origin, noumenal and mechanical. They are due in the first place to the action of things in themselves upon the noumenal conditions of the self, and also in the second place to the action of material bodies upon the sense-organs and the brain. To take the latter first. Light reflected from objects, and acting on the retina, gives rise to sensations of colour. For such causal interrelations there exists, Kant teaches, the same kind of empirical evidence as for the causal interaction of material bodies.[941] Our sensational experiences are as truly events in time as are mechanical happenings in space. In this way, however, we can account only for the existence of our sensations and for the order in which they make their appearance in or to consciousness, not for our awareness of them. To state the point by means of an illustration. The impinging of one billiard ball upon another accounts causally for the motion which then appears in the second ball. But no one would dream of asserting that by itself it accounts for our consciousness of that second motion. We may contend that in an exactly similar manner, to the same extent, no more and no less, the action of an object upon the brain accounts only for the occurrence of a visual sensation as an event in the empirical time sequence. A sensation just as little as a motion can carry its own consciousness with it. To regard that as ever possible is ultimately to endow events in time with the capacity of apprehending objects in space. In dealing with causal connections in space and time we do not require to discuss the problem of knowledge proper, namely, how it is possible to have or acquire knowledge, whether of a motion in space or of a sensation in time. When we raise that further question we have to adopt a very different standpoint, and to take into account a much greater complexity of conditions.{276}

Kant applies this point of view no less rigorously to feelings, emotions, and desires than to the sensations of the special senses. All of them, he teaches, are ‘animal’[942] in character. They are one and all conditioned by, and explicable only in terms of, the particular constitution of the animal organism. They one and all belong to the realm of appearance.[943]

The term ‘sensation’ may also, however, be applied in a wider sense to signify the material of knowledge in so far as it is noumenally conditioned. Thus viewed, sensations are due, not to the action of physical stimuli upon the bodily organs, but to the affection by things in themselves of those factors in the noumenal conditions of the self which correspond to “sensibility.” Kant is culpably careless in failing to distinguish those two very different meanings of the phrase ‘given manifold.’ The language which he employs is thoroughly ambiguous. Just as he frequently speaks as if the synthetic processes were conscious activities exerted by the self, so also he frequently uses language which implies that the manifold upon which these processes act is identical with the sensations of the special senses. But the sensations of the bodily senses, even if reducible to it, can at most form only part of it. The synthetic processes, interpreting the manifold in accordance with the fixed forms, space, time, and the categories, generate the spatial world within which objects are apprehended as causally interacting and as giving rise through their action upon the sense-organs to the various special sensations as events in time. Sensations, as mechanically caused, are thus on the same plane as other appearances. They depend upon the same generating conditions as the motions which produce them. As minor incidents within a more comprehensive totality they cannot possibly represent the material out of which the whole has been constructed. To explain the phenomenal world as constructed out of the sensations of the special senses is virtually to equate it with a small selection of its constituent parts. Such professed explanation also commits the further absurdity of attempting to account for the origin of the phenomenal world by means of events which can exist only under the conditions which it itself supplies. The manifold of the special senses and the primary manifold are radically distinct. The former is due to material bodies acting upon the material sense-organs. The latter is the product of noumenal agencies acting upon “outer sense,” i.e. upon those noumenal conditions of the self{277} which constitute our “sensibility”; it is much more comprehensive than the former; it must contain the material for all modes of objective existence, including many that are usually regarded as purely mental.[944]

To turn, now, to the other aspect of experience. What are the factors which condition its form? What must we postulate in order to account for the existence of consciousness and for the unitary form in which alone it can appear? Kant’s answer is again ambiguous. He fails sufficiently to insist upon distinctions which yet are absolutely vital to any genuine understanding of the new and revolutionary positions towards which he is feeling his way. The synthetic processes which in the subjective and objective deductions are proved to condition all experience may be interpreted either as conscious or as non-conscious activities, and may be ascribed either to the agency of the individual self or to noumenal conditions which fall outside the realm of possible definition. Now, though Kant’s own expositions remain thoroughly ambiguous, the results of the Critical enquiry would seem—at least so long as the fundamental distinction between matter and form is held to and the temporally sequent aspect of experience is kept in view—to be decisive in favour of the latter alternative in each case. The synthetic processes must take place and complete themselves before any consciousness can exist at all. And as they thus precondition consciousness, they cannot themselves be known to be conscious; and not being known to be conscious, it is not even certain that they may legitimately be described as mental. We have, indeed, to conceive them on the analogy of our mental processes, but that may only be because of the limitation of our knowledge to the data of experience. Further, we have no right to conceive them as the activities of a noumenal self. We know the self only as conscious, and the synthetic processes, being the generating conditions of consciousness, are also the generating conditions of the only self for which our experience can vouch. Kant, viewing as he does the temporal aspect of human experience as fundamental, would seem to be justified in naming these processes “synthetic.” For consciousness in its very nature would seem to involve the carrying over of content from one time to other times, and the construction of a more comprehensive total consciousness from the elements thus combined. Kant is here analysing in its simplest and most fundamental form {278}that aspect of consciousness which William James has described in the Principles of Psychology,[945] and which we may entitle the telescoping of earlier mental states into the successive experiences that include them. They telescope in a manner which can never befall the successive events in a causal series, and which is not explicable by any scheme of relations derivable from the physical sphere.

Obviously, what Kant does is to apply to the interpretation of the noumenal conditions of our conscious experience a distinction derived by analogy from conscious experience itself—the distinction, namely, between our mental processes and the sensuous material with which they deal. The application of such a distinction may be inevitable in any attempt to explain human experience; but it can very easily, unless carefully guarded, prove a source of serious misunderstanding. Just as the synthetic processes which generate consciousness are not known to be themselves conscious, so also the manifold cannot be identified with the sensations of the bodily senses. These last are events in time, and are effects not of noumenal but of mechanical causes.

Kant’s conclusion when developed on consistent Critical lines, and therefore in phenomenalist terms, is twofold: positive, to the effect that consciousness, for all that our analysis can prove to the contrary, may be merely a resultant, derivative from and dependent upon a complexity of conditions; and negative, to the effect that though these conditions may by analogy be described as consisting of synthetic processes acting upon a given material, they are in their real nature unknowable by us. Even their bare possibility we cannot profess to comprehend. We postulate them only because given experience is demonstrably not self-explanatory and would seem to refer us for explanation to some such antecedent generative grounds.

Kant, as we have already emphasised, obscures his position by the way in which he frequently speaks of the transcendental unity of apperception as the supreme condition of our experience. At times he even speaks as if it were the {279}source of the synthetic processes. That cannot, however, be regarded as his real teaching. Self-consciousness (and the unity of apperception, in so far as it finds expression through self-consciousness) rests upon the same complexity of conditions as does outer experience, and therefore may be merely a product or resultant. It is, as he insists in the Paralogisms, the emptiest of all our concepts, and can afford no sufficient ground for asserting the self to be an abiding personality. We cannot by theoretical analysis of the facts of experience or of the nature of self-consciousness prove anything whatsoever in regard to the ultimate nature of the self.

Now Kant is here giving a new, and quite revolutionary, interpretation of the distinction between the subjective and the objective. The objective is for the Cartesians the independently real;[946] the subjective is that which has an altogether different kind of existence in what is entitled the field of consciousness. Kant, on the other hand, from his phenomenalist standpoint, views existences as objective when they are determined by purely physical causes, and as subjective when they also depend upon physiological and psychological conditions. On this latter view the difference between the two is no longer a difference of kind; it becomes a difference merely of degree. Objective existences, owing to the simplicity and recurrent character of their conditions, are uniform. Subjective existences resting upon conditions which are too complex to be frequently recurrent, are by contrast extremely variable. But both types of existence are objective in the sense that they are objects, and immediate objects, for consciousness. Subjective states do not run parallel with the objective system of natural existences, nor are they additional to it. For they do not constitute our consciousness of nature; they are themselves part of the natural order which consciousness reveals. That they contrast with physical existences in being unextended and incapable of location in space is what Kant would seem by implication to assert, but he challenges Descartes’ right to infer from this particular difference a complete diversity in their whole nature. Sensations, feelings, emotions, and desires, so far as they are experienced by us, constitute the empirical self which is an objective existence, integrally connected with the material environment, in terms of which alone it can be understood. In other words, the distinction between the subjective and the objective is now made to fall within the system of natural{280} law. The subjective is not opposite in nature to the objective, but is a subspecies within it.

The revolutionary character of this reformulation of Cartesian distinctions may perhaps be expressed by saying that what Kant is really doing is to substitute the distinction between appearance and reality for the Cartesian dualism of the mental and the material. The psychical is a title for a certain class of known existences, i.e. of appearances; and they form together with the physical a single system. But underlying this entire system, conditioning both physical and psychical phenomena, is the realm of noumenal existence; and when the question of the possibility of knowledge, that is, of the experiencing of such a comprehensive natural system, is raised, it is to this noumenal sphere that we are referred. Everything experienced, even a sensation or desire, is an event; but the experiencing of it is an act of awareness, and calls for an explanation of an altogether different kind.

Thus Kant completely restates the problem of knowledge. The problem is not how, starting from the subjective, the individual can come to knowledge of the independently real; but how, if a common world is alone immediately apprehended, the inner private life of the self-conscious being can be possible, and how such inner experience is to be interpreted. How does it come about that though sensations, feelings, etc., are events no less mechanically conditioned than motions in space, and constitute with the latter a single system conformed to natural law, they yet differ from all other classes of natural events in that they can be experienced only by a single consciousness. To this question Kant replies in terms of his fundamental distinction between appearance and reality. Though everything of which we are conscious may legitimately be studied in terms of the natural system to which it belongs, consciousness itself cannot be so regarded. In attempting to define it we are carried beyond the phenomenal to its noumenal conditions. In other words, it constitutes a problem, the complete data of which are not at our disposal. This is by itself a sufficient reason for our incapacity to explain why the states of each empirical self can never be apprehended save by a single consciousness, or otherwise stated, why each consciousness is limited, as regards sensations and feelings, exclusively to those which arise in connection with some one animal organism. It at least precludes us from dogmatically asserting that this is due to their being subjective in the dualistic and Cartesian sense of that term—namely, as constituting, or being states of, the knowing self.{281}

A diagram may serve, though very crudely, to illustrate Kant’s phenomenalist interpretation of the cognitive situation.


    ESA = Empirical self of the conscious Being A.
    ESA = Empirical self of the conscious Being A.
    ESB = Empirical self of the conscious Being B.
    NCA = Noumenal conditions of the conscious Being A.
    NCB = Noumenal conditions of the conscious Being B.
l, m, n = Objects in space.
x1, y1, z1 = Sensations caused by objects l, m, n acting on the sense-organs of the empirical self A.
x2, y2, z2= Sensations caused by 1, m, n acting on the sense-organs of the empirical self B.
  NCEW = Noumenal conditions of the empirical world.

Everything in this empirical world is equally open to the consciousness of both A and B, save only certain psychical events that are conditioned by physiological and psychological factors. x1, y1, z1 can be apprehended only by A; x2, y2, z2 can be apprehended only by B. Otherwise A and B experience one and the same world; the body of B is perceived by A in the same manner in which he perceives his own body. This is true a fortiori of all other material existences. Further, these material existences are known with the same immediacy as the subjective states. As regards the relation in which NCA, NCB, and NCEW stand to one another, no assertions can be made, save, as above indicated,[947] such conjectural statements as may precariously be derived through argument by analogy from distinctions that fall within our human experience.[948]

Kant’s phenomenalism thus involves an objectivist view of{282} individual selves and of their interrelations. They fall within the single common world of space. Within this phenomenal world they stand in external, mechanical relations to one another. They are apprehended as embodied, with known contents, sensations, feelings, and desires, composing their inner experience. There is, from this point of view, no problem of knowledge. On this plane we have to deal only with events known, not with any process of apprehension. Even the components of the empirical self, the subject-matter of empirical psychology, are not processes of apprehension, but apprehended existences. It is only when we make a regress beyond the phenomenal as such to the conditions which render it possible, that the problem of knowledge arises at all. And with this regress we are brought to the real crux of the whole question—the reconciliation of this phenomenalism with the conditions of our self-consciousness. For we have then to take into account the fundamental fact that each self is not only an animal existence within the phenomenal world, but also in its powers of apprehension coequal with it. The self known is external to the objects known; the self that knows is conscious of itself as comprehending within the field of its consciousness the wider universe in infinite space.

Such considerations would, at first sight, seem to force us to modify our phenomenalist standpoint in the direction of subjectivism. For in what other manner can we hope to unite the two aspects of the self, the known conditions of its finite existence and the consciousness through which it correlates with the universe as a whole? In the one aspect it is a part of appearance; in the other it connects with that which makes appearance possible at all.

Quite frequently it is the subjectivist solution which Kant seems to adopt. Objects known are “mere representations,” “states of the identical self.” Everything outside the individual mind is real; appearances are purely individual in origin. But such a position is inconsistent with the deeper implications of Kant’s Critical teaching, and would involve the entire ignoring of the many suggestions which point to a fundamentally different and much more adequate standpoint. The individual is himself known only as appearance, and cannot, therefore, be the medium in and through which appearances exist. Though appearances exist only in and through consciousness, they are not due to any causes which can legitimately be described as individual. From this standpoint Kant would seem to distinguish between the grounds and conditions of phenomenal existence and the special{283} determining causes of individual consciousness. Transcendental conditions generate consciousness of the relatively permanent and objective world in space and time; empirical conditions within this space and time world determine the sensuous modes through which special portions of this infinite and uniform world appear diversely to different minds.

This, however, is a point of view which is only suggested, and, as we have already observed,[949] the form in which it is outlined suggests many objections and difficulties. Consciousness of the objective world in space and time does not exist complete with one portion of it more specifically determined in terms of actual sense-perceptions. Rather the consciousness of the single world in space and time is gradually developed through and out of sense experience of limited portions of it. We have still to consider the various sections in the Analytic of Principles (especially the section added in the second edition on the Refutation of Idealism) and in the Dialectic, in which Kant further develops this standpoint. But even after doing so, we shall be forced to recognise that Kant leaves undiscussed many of the most obvious objections to which his phenomenalism lies open. To the very last he fails to state in any really adequate manner how from the phenomenalist standpoint he would regard the world described in mechanical terms by science as being related to the world of ordinary sense-experience,[950] or how different individual consciousnesses are related to one another. The new form, however, in which these old-time problems here emerge is the best possible proof of the revolutionary character of Kant’s Critical enquiries. For{284} these problems are no longer formulated in terms of the individualistic presuppositions which govern the thinking of all Kant’s predecessors, even that of Hume. The concealed presuppositions are now called in question, and are made the subject of explicit discussion. But further comment must meantime be deferred.[951]


The argument of the second edition transcendental deduction can be reduced to the following eight points:

(1)[952] It opens with the statement of a fundamental assumption which Kant does not dream of questioning and of which he nowhere attempts to offer proof. The representation of combination is the one kind of representation which can never be given through sense. It is not so given even in the pure forms of space and time yielded by outer and inner sense.[953] It is due to an act of spontaneity, which as such must be performed by the understanding. As it is one and the same for every kind of combination, it may be called by the general name of synthesis. And as all combination, without exception, is due to this source, its dissolution, that is, analysis, which seems to be its opposite, always presupposes it.

(2)[954] Besides the manifold and its synthesis a further factor is involved in the conception of combination, namely, the representation of the unity of the manifold. The combination which is necessary to and constitutes knowledge is representation of the synthetical unity of the manifold. This is a factor additional to synthesis and to the manifold synthesised. For such representation cannot arise out of any antecedent consciousness of synthesis. On the contrary, it is only through supervention upon the unitary synthesis that the conception of the combination becomes possible. In other words, the representation of unity conditions consciousness of synthesis, and therefore cannot be the outcome or product of it. This is an application, or rather generalisation, of a position which in the first edition is developed only in reference to the empirical process of recognition. Recognition preconditions consciousness, and therefore cannot be subsequent upon it.

(3)[955] The unity thus represented is not, however, that{285} which is expressed through the category of unity. The consciousness of unity which is involved in the conception of synthesis is that of apperception or transcendental self-consciousness. This is the highest and most universal form of unity, for it is a presupposition of the unity of all possible concepts, whether analytic or synthetic, in the various forms of judgment.

(4)[956] A manifold though given is not for that reason also represented. It must be possible for the ‘I think’ to accompany it and all my other representations:

“...for otherwise something would be represented in me which could not be thought at all; and that is equivalent to saying that the representation would be impossible or at least would be nothing to me.”[957]

But to ascribe a manifold as my representations to the identical self is to comprehend them, as synthetically connected, in one apperception.[958] Only what can be combined in one consciousness can be related to the ‘I think.’ The analytic unity of self-consciousness presupposes the synthetic unity of the manifold.

(5)[959] The unity of apperception is analytic or self-identical. It expresses itself through the proposition, I am I. But being thus pure identity without content of its own, it cannot be conscious of itself in and by itself. Its unity and constancy can have meaning only through contrast to the variety and changeableness of its specific experiences; and yet, at the same time, it is also true that such manifoldness will destroy all possibility of unity unless it be reconcileable with it. The variety can contribute to the conditioning of apperception only in so far as it is capable of being combined into a single consciousness. Through synthetic unifying of the manifold the self comes to consciousness both of itself and of the manifold.

(6)[960] The transcendental original unity of apperception is an objective, not a merely subjective, unity. Its conditions are also the conditions in and through which we acquire consciousness of objects. An object is that in the conception of which the manifold of given intuitions is combined. (This point, though central to the argument, is more adequately developed in the first than in the second edition.) Such combination requires unity of consciousness. Thus the same unity which conditions apperception likewise conditions the {286}relation of representations to an object. The unity of pure apperception may therefore be described as an objective unity for two reasons: first, because it can apprehend its own analytical unity only through discovery of unity in the given, and secondly, for the reason that such synthetical unifying of the manifold is also the process whereby representations acquire reference to objects.

(7)[961] Kant reinforces this conclusion, and shows its further significance, by analysis of the act of judgment. The logical definition of judgment, as the representation of a relation between two concepts, has many defects. These, however, are all traceable to its initial failure to explain, or even to recognise, the nature of the assertion which judgment as such claims to make. Judgment asserts relations of a quite unique kind, altogether different from those which exist between ideas connected through association. If, for instance, on seeing a body the sensations of weight due to the attempt to raise it are suggested by association, there is nothing but subjective sequence; but if we form the judgment that the body is heavy, the two representations are then connected together in the object. This is what is intended by the copula ‘is.’ It is a relational term through which the objective unity of given representations is distinguished from the subjective. It indicates that the representations stand in objective relation under the pure unity of apperception, and not merely in subjective relation owing to the play of association in the individual mind. “Judgment is nothing but the mode of bringing cognitions to the objective unity of apperception,” i.e. of giving to them a validity which holds independently of the subjective processes through which it is apprehended. Objective relations are not, of course, all necessary or universal; and a judgment may, therefore, assert a relation which is empirical and contingent. None the less the fundamental distinction between it and any mere relation of association still persists. The empirical relation is still in the judgment asserted to be objective. The subject and the predicate are asserted, in the particular case or cases to which the judgment refers, to be connected in the object and not merely in the mind of the subject. Or otherwise stated, though subject and predicate are not themselves declared to be necessarily and universally related to one another, their contingent relation has to be viewed as objectively, and therefore necessarily, grounded. Judgment always presupposes the existence of necessary relations even when it is not concerned to assert them. Judgment is the organ of objective knowledge, and is therefore{287} bound up, indirectly when not directly, with the universality and necessity which are the sole criteria of knowledge. The judgment expressive of contingency is still judgment, and is therefore no less necessary in its conditions, and no less objective in its validity, than is a universal judgment of the scientific type. To use Kant’s own terminology, judgment acquires objective validity through participation in the necessary unity of apperception. In so doing it is made to embody those principles of the objective determination of all representations through which alone cognition is possible.

(8)[962] As judgment is nothing but the mode of bringing cognitions to the objective unity of apperception, it follows that the categories, which in the metaphysical deduction have been proved to be the possible functions in judging, are the conditions in and through which such pure apperception becomes possible. Apperception conditions experience, and the unity which both demand for their possibility is that of the categories.


Before passing to the remaining sections of the deduction,[963] which are supplementary rather than essential, I may add comment upon the above points. Only (7) and (8) call for special consideration. They represent a form of argument which has no counterpart in the first edition. As we noted,[964] the first edition argument is defective owing to its failure to demonstrate that the categories constitute the unity which is necessary to knowledge. By introducing in the second edition this analysis of judgment, and by showing the inseparable connection between pure apperception, objective consciousness and judgment, this defect is in some degree removed. As the categories correspond to the possible functions of judgment, their objective validity is thereby established. By this means also the connection which in Kant’s view exists between the metaphysical and the transcendental deductions receives for the first time proper recognition. The categories which in the former deduction are discovered and systematised through logical analysis of the form of judgment, are in the latter deduction, through transcendental analysis of the function of judgment, shown to be just those forms of relation which are necessary to the possibility of knowledge. It must, however, be noted that the transcendental argument is brought to completion only through assumption of the adequacy of the metaphysical deduction. No independent attempt is made to show that the particular categories obtained in the metaphysical deduction{288} are those which are required, that there are no others, or that all the twelve are indispensable.

(7) is a development of an argument which first appears in the Prolegomena. The statement of it there given is, however, extremely confused, owing to the distinction which Kant most unfortunately introduces[965] between judgments of experience and judgments of perception. That distinction is entirely worthless and can only serve to mislead the reader. It cuts at the very root of Kant’s Critical teaching. Judgments of perception involve, Kant says, no category of the understanding, but only what he is pleased to call the “logical connection of perceptions in a thinking subject.” What that may be he nowhere explains, save by adding[966] that in it perceptions are “compared and conjoined in a consciousness of my state” (also spoken of by Kant as “empirical consciousness”), and not “in consciousness in general.”

“All our judgments are at first mere judgments of perception; they hold good merely for us (that is, for the individual subject), and we do not till afterwards give them a new reference, namely, to an object.... To illustrate the matter: that the room is warm, sugar sweet, and wormwood bitter—these are merely subjectively valid judgments. I do not at all demand that I myself should at all times, or that every other person should, find the facts to be what I now assert; they only express a reference of two sensations to the same subject, to myself, and that only in my present state of perception. Consequently they are not intended to be valid of the object. Such judgments I have named those of perception. Judgments of experience are of quite a different nature. What experience teaches me under certain circumstances, it must teach me always and teach everybody, and its validity is not limited to the subject or to its state at a particular time.”[967]

The illegitimacy and the thoroughly misleading character of this distinction hardly require to be pointed out. Obviously Kant is here confusing assertion of contingency and contingency of assertion.[968] A judgment of contingency, in order to be valid, must itself be necessary. Even a momentary state of the self is referable to an object in judgment only if that object is causally, and therefore necessarily, concerned in its production.[969]

The distinction is repeated in § 22 as follows:

“Thinking is the combining of representations in one consciousness. This combination is either merely relative to the subject, and is contingent and subjective, or is absolute, and is necessary or{289} objective. The combination of representations in one consciousness is judgment. Thinking, therefore, is the same as judging, or the relating of representations to judgments in general. Judgments, therefore, are either merely subjective, or they are objective. They are subjective when representations are related to a consciousness in one subject only, and are combined in it alone. They are objective when they are united in a consciousness in general, that is, necessarily.”[970]

To accept this distinction is to throw the entire argument into confusion. This Kant seems to have himself recognised in the interval between the Prolegomena and the second edition of the Critique. For in the section before us there is no trace of it. The opposition is no longer between subjective and objective judgment, but only between association of ideas and judgment which as such is always objective. The distinction drawn in the Prolegomena is only, indeed, a more definite formulation of the distinction which runs through the first edition of the Critique between the indeterminate and the determinate object of consciousness. The more definite formulation of it seems, however, to have had the happy effect of enabling Kant to realise the illegitimacy of any such distinction.


We may now proceed to consider the remaining sections.[971] In section 21[972] Kant makes a very surprising statement. The above argument, which he summarises in a sentence, yields, he declares, “the beginning of a deduction of the pure concepts of understanding.” This can hardly be taken as representing Kant’s real estimate of the significance of the preceding argument, and would seem to be due to a temporary preoccupation with the problems that centre in the doctrine of schematism. So far, Kant adds in explanation, no account has been taken of the particular manner in which the manifold of empirical intuition is supplied to us.[973] The necessary supplement, consisting of a very brief outline statement of the doctrine of schematism, is given in section 26.[974] It differs from the teaching of the special chapter devoted to schematism in emphasising space equally with time. The doctrine of pure a priori manifolds is incidentally asserted.[975] Section 26 concludes by consideration of the question why appearances must conform to the a priori {290}categories. It is no more surprising, Kant claims, than that they should agree with the a priori forms of intuition. The categories and the intuitional forms are relative to the same subject to which the appearances are relative; and the appearances “as mere representations are subject to no law of connection save that which the combining faculty prescribes.”

The summary of the deduction given in section 27 discusses the three possible theories regarding the origin of pure concepts, viz. those of generatio aequivoca (out of experience), epigenesis, and preformation. The first is disproved by the deduction. The second is the doctrine of the deduction and fulfils all the requirements of demonstration. The proof that the categories are at once independent of experience and yet also universally valid for all experience is of the strongest possible kind, namely, that they make experience itself possible. The third theory, that the categories, while subjective and self-discovered, originate in faculties which are implanted in us by our Creator and which are so formed as to yield concepts in harmony with the laws of nature, lies open to two main objections. In the first place, this is an hypothesis capable of accounting equally well for any kind of a priori whatsoever; the predetermined powers of judgment can be multiplied without limit. But a second objection is decisive, namely, that on such a theory the categories would lack the particular kind of necessity which is required. They would express only the necessities imposed upon our thinking by the constitution of our minds, and would not justify any assertion of necessary connection in the object. Kant might also have added,[976] that this hypothesis is metaphysical, and therefore offers in explanation of the empirical validity of a priori concepts a theory which rests upon and involves their unconditioned employment. That is a criticism which is reinforced by the teaching of the Dialectic.

To return now to the omitted sections 22 to 25. Section 22 makes no fresh contribution to the argument of the first edition. Its teaching in regard to pure intuition and mathematical knowledge has already been commented upon. In section 23 Kant dwells upon an interesting consequence of the argument of the deduction. The categories have a wider scope than the pure forms of sense. Since the argument of the deduction has shown that judgment is the indispensable instrument both for reducing a manifold to the unity of apperception and also for conferring upon representations a relation to an object, it follows that the categories which are simply the possible functions of unity in judgment are valid for any and{291} every consciousness that is sensuously conditioned and whose knowledge is therefore acquired through synthesis of a given manifold. Though such consciousness may not intuit in terms of space and time, it must none the less apprehend objects in terms of the categories. The categories thus extend to objects of sensuous intuition in general. They are not, however, valid of objects as such, that is, of things in themselves. As empty relational forms they have meaning only in reference to a given matter; and as instruments for the reduction of variety to the unity of apperception their validity has been proved only for conscious and sensuous experience. Even if the possibility of a non-sensuous intuitive understanding, capable of apprehending things in themselves, be granted, we have no sufficient ground for asserting that the forms which such understanding will employ must coincide with the categories.[977] These are points which will come up for discussion in connection with Kant’s more detailed argument in the chapter on the distinction between phenomena and noumena.[978]

The heading to section 24 is decidedly misleading. The phrase “objects of the senses in general” might be synonymous with “objects of intuition in general” of the preceding section. To interpret it, however, by the contents of the section, it means “objects of our senses.” This section ought, therefore, to form part of section 26, which in its opening sentences supplies its proper introduction. (It may also be noted that the opening sentences of section 24 are a needless repetition of section 23. This would seem to show that it was not written in immediate continuation of it.) The first three paragraphs of section 24 expound the same doctrine of schematism as that outlined in section 26, save that time alone is referred to. The remaining paragraphs of section 24 deal with the connected doctrine of inner sense. Section 25 deals with certain consequences which follow from that doctrine of inner sense.[979]


We have still to consider a doctrine of great importance in Kant’s thinking, that of inner sense. The significance of this doctrine is almost inversely proportionate to the scantiness and obscurity of the passages in which it is expounded and developed. Much of the indefiniteness and illusiveness of the current interpretations of Kant would seem{292} to be directly traceable to the commentator’s failure to appreciate the position which it occupies in Kant’s system. Several of Kant’s chief results are given as deductions from it, while it itself, in turn, is largely inspired by the need for a secure basis upon which these positions may be made to rest. The relation of the doctrine to its consequences is thus twofold. Kant formulates it in order to safeguard or rather to justify certain conclusions; and yet these conclusions have themselves in part been arrived at owing to his readiness to accept such a doctrine, and to what would seem to have been his almost instinctive feeling of its kinship (notwithstanding the very crude form in which alone he was able to formulate it) with Critical teaching. It was probably one of the earliest of the many new tenets which Kant adopted in the years immediately subsequent to the publication of the inaugural Dissertation, but it first received adequate statement in the second edition of the Critique. Kant took advantage of the second edition to reply to certain criticisms to which his view of time had given rise, and in so doing was compelled to formulate the doctrine of inner sense in a much more explicit manner. Hitherto he had assumed its truth, but had not, as it would seem, sufficiently reflected upon the various connected conclusions to which he was thereby committed. This is one of the many instances which show how what is most fundamental in Kant’s thinking is frequently that of which he was himself least definitely aware. Like other thinkers, he was most apt to discuss what he himself was inclined to question and feel doubt over. The sources of his insight as well as the causes of his failure often lay beyond the purview of his explicitly developed tenets; and only under the stimulus of criticism was he constrained and enabled to bring them within the circle of reasoned conviction. We may venture the prophecy that if Kant had been able to devote several years more to the maturing of the problems which in the face of so many difficulties he had brought thus far, the doctrine of inner sense, or rather the doctrines to which it gives expression, would have been placed in the forefront of his teaching, and their systematic interconnection, both in the way of ground and of consequence, with all his chief tenets would have been traced and securely established.

This would have involved, however, two very important changes. In the first place, Kant would have had to recognise the unsatisfactory character of the supposed analogy between inner and outer sense. As already remarked,[980] no great thinker, except Locke, has attempted to interpret inner consciousness{293} on the analogy of the senses; and the obscurities of Kant’s argument are not, therefore, to be excused on the ground that “the difficulty, how a subject can have an internal intuition of itself, is common to every theory.” Secondly, Kant would have had to define the relation in which he conceived this part of his teaching to stand to his theory of consciousness. But both these changes could have been made without requiring that he should give up the doctrines which are mainly responsible for his theory of inner sense, namely, that there can be no awareness of awareness, but only of existences which are objective, and that there is consequently no consciousness of the generative, synthetic processes[981] which constitute consciousness on its subjective side. It is largely in virtue of these conclusions that Kant’s phenomenalism differs from the subjective idealism of his predecessors. If we ignore or reject them, merely because of the obviously unsatisfactory manner in which alone Kant has been able to formulate them, we rule ourselves out from understanding the intention and purpose of much that is most characteristic of Critical teaching.

The doctrine of inner sense, as expounded by Locke, suffers from an ambiguity which seems almost inseparable from it, namely, the confusion between inner sense, on the one hand as a sense in some degree analogous in nature to what may be called outer sense, and on the other as consisting in self-conscious reflection. This same confusion is traceable throughout the Critique, and is, as we shall find, in large part responsible for Kant’s failure to recognise, independently of outside criticism, the central and indispensable part which this doctrine is called upon to play in his system.

The doctrine is stated by Kant as follows. Just as outer sense is affected by noumenal agencies, and so yields a manifold arranged in terms of a form peculiar to it, namely, space, so inner sense is affected by the mind itself and its inner state.[982] The manifold thereby caused is arranged in terms of a form peculiar to inner sense, namely, time. The content thus arranged falls into two main divisions. On the one hand we have feelings, desires, volitions, that is, states of the mind in the strict sense, subjective non-spatial existences. On the other hand we have sensations, perceptions, images, concepts, in a word, representations (Vorstellungen) of every possible type. These latter all refer to the external world in space, and yet, according to Kant, speaking from the limited point of view of a critique of knowledge, {294}form the proper content of inner sense. “...the representations of the outer senses constitute the actual material with which we occupy our minds,”[983] “the whole material of knowledge even for our inner sense.”[984] (These statements, it may be observed, are first made in the second edition.) As Kant explains himself in B 67-8, he would seem to mean that the mind in the process of “setting” representations of outer sense in space affects itself, and is therefore constrained to arrange the given representations likewise in time. No new content, additional to that of outer sense, is thereby generated, but what previously as object of outer sense existed merely in space is now also subjected to conditions of time. The representations of outer sense are all by their very nature likewise representations of inner sense. To outer sense is due both their content and their spatial form; to inner sense they owe only the additional form of time; their content remains unaffected in the process of being taken over by a second sense. This yields such explanation as is possible of Kant’s assertion in A 33 that “time can never be a determination of outer appearances.” He may be taken as meaning that time is never a determination of outer sense as such, but only of its contents as always likewise subject to the form of inner sense.[985]

This is how Kant formulates his position from the extreme subjectivist point of view which omits to draw any distinction between representation and its object, between inner states of the self and appearances in space. All representations, he says,[986] all appearances without exception, are states of inner sense, modifications of the mind. Some exist only in time, some exist both in space and in time; but all alike are modes of the identical self, mere representations (blosse Vorstellungen). Though appearances may exist outside one another in space, space itself exists only as representation, merely “in us.”

Now without seeking to deny that this is a view which we find in the second edition of the Critique as well as in the first,[987] and that even in passages which are obviously quite late in date of writing Kant frequently speaks in terms which conform to it, we must be no less insistent in maintaining that{295} an alternative view more and more comes to the front in proportion as Kant gains mastery over the conflicting tendencies that go to constitute his new Critical teaching. From the very first he uses language which implies that some kind of distinction must be drawn between representations and objects represented, between subjective cognitive states in the proper sense of the term and existences in space.

“Time can never be a determination of outer appearances. It belongs neither to form nor position, etc. On the other hand it determines the relation of representations in our inner state.”[988]

Similarly in those very sentences in which he asserts all appearances to be blosse Vorstellungen, a distinction is none the less implied.

“Time is the formal a priori condition of all appearances in general. Space, as the pure form of all outer intuition, is as a priori condition limited exclusively (bloss) to outer appearances. On the other hand as all representations, whether they have outer things as their object or not, still in themselves belong, as determinations of the mind, to the inner state, and this inner state is subject to the formal condition of inner intuition, that is of time, time is an a priori condition of all appearance whatever. It is, indeed, the immediate condition of the inner appearance (of our souls), and thereby mediately likewise of outer appearances.”[989]

As the words which I have italicised show, Kant, even in the very sentence in which he asserts outer representations to be inner states, none the less recognises that appearances in space are not representations in the same meaning of that term as are subjective states. They are the objects of representation, not representation itself. The latter alone is correctly describable as a state of the mind. The former may be conditioned by representation, and may therefore be describable as appearances, but are not for that reason to be equated with representation. But before the grounds and nature of this distinction can be formulated in the proper Critical terms, we must consider the reasons which induced Kant to commit himself to this obscure and difficult doctrine of inner sense. As I shall try to show, it is no mere excrescence upon his system; on the contrary, it is inseparably bound up with all his main tenets.

One of the chief influences which constrained Kant to develop this doctrine is the conclusion, so essential to his position, that knowledge must always involve an intuitional{296} manifold in addition to a priori forms and concepts. That being so, he was bound to deny to the mind all power of gaining knowledge by mere reflection. If our mental activities and states lay open to direct inspection, we should have to recognise in the mind a non-sensuous intuitional power. Through self-consciousness or reflection we should acquire knowledge independently of sense. Such apprehension, though limited to the mind’s own operations and states, would none the less be knowledge, and yet would not conform to the conditions which, as the transcendental deduction has shown, are involved in all knowledge. In Kant’s view the belief that we possess self-consciousness of this type, a power of reflection thus conceived, is wholly illusory. To assume any such faculty would be to endow the mind with occult or mystical powers, and would throw us back upon the Leibnizian rationalism, which traces to such reflection our consciousness of the categories, and which rears upon this foundation the entire body of metaphysical science.[990]

The complementary negative conclusion of the transcendental deduction is a no less fundamental and constraining influence in compelling Kant to develop a doctrine of inner sense. If all knowledge is knowledge of appearances, or if, as he states his position in the Analytic of Principles,[991] our knowledge can extend no further than sense experience and inference from such experience, either knowledge of our inner states must be mediated, like our knowledge of outer objects, by sensation, or we can have no knowledge of them whatsoever. On Critical principles, consistently applied, there can be no middle course between acceptance of an indirect empirical knowledge of the mind and assertion of its unknowableness. Mental activities may perhaps be thought in terms of the pure forms of understanding, but in that case their conception will remain as purely problematic and as indeterminate as the conception of the thing in itself. It is impossible for Kant to admit immediate consciousness of the mind’s real activities and states, and at the same time to deny that we can have knowledge of things in themselves. The Aesthetic, in proving that everything in space and time is appearance, implicitly assumes the impossibility of direct self-conscious reflection; and the transcendental deduction in showing that all knowledge involves as correlative factors both sense and thought, has reinforced this conclusion, and{297} calls for its more explicit recognition, in reference to the more inward aspect of experience.

As we have already noted,[992] Kant’s doctrine of inner sense was probably adopted in the early ’seventies, and though it is not itself definitely formulated in the first edition, the chief consequence that follows from it is clearly recognised. Thus in the Aesthetic Kant draws the conclusion that, as time is the form of inner sense, everything apprehended in time, and consequently all inner states and activities, can be known only as appearances. The mind (meaning thereby the ultimate conditioning grounds of consciousness) is as indirectly known as is any other mode of noumenal existence. In the Analytic, whenever he is called upon to express himself upon this and kindred points, he continues to hold to this position; and in the section on the Paralogisms all the main consequences that follow from its acceptance are drawn in the most explicit and unambiguous manner. It is argued that as the inner world, the feelings, volitions and representations of which we are conscious, is a world constructed out of a given manifold yielded by inner sense, and is therefore known only as the appearance of a deeper reality which we have no power of apprehending, it possesses no superiority either of certainty or of immediacy over the outer world of objects in space. We have immediate consciousness of both alike, but in both cases this immediate consciousness rests upon the transcendental synthetic processes whereby such consciousness is conditioned and generated. The transcendental activities fall outside the field of empirical consciousness and therefore of knowledge.

Thus Kant would seem to be maintaining that the radical error committed by the subjective idealists, and with which all the main defects of their teaching are inseparably bound up, lies in their ascription to the mind of a power of direct self-conscious reflection, and consequently in their confusion of the transcendental activities which condition consciousness with the inner states and processes which such consciousness reveals. This has led them to ascribe priority and independence to our inner states, and to regard outer objects as known only by an inference from them. The Critical teaching insists on the distinction between appearance and reality, applies it to the inner life, and so restores to our consciousness of the outer world the certainty and immediacy of which subjective idealism would profess to deprive it. Such are the important conclusions at which Kant arrives in his various “refutations of idealism”; and it will be advisable to consider{298} these refutations in full detail before attempting to complete our statement of his doctrine of inner sense.


Kant has in a number of different passages attempted to define his Critical standpoint in its distinction from the positions of Descartes and Berkeley. Consideration of these will enable us to follow Kant in his gradual recognition of the manifold consequences to which he is committed by his substitution of inner sense for direct self-conscious intuition or reflection, or rather of the various congenial tenets which it gives him the right consistently to defend and maintain. In Kant’s Critical writings we find no less than seven different statements of his refutation of idealism: (I.) in the fourth Paralogism of the first edition of the Critique; (II.) in section 13 (Anm. ii. and iii.) of the Prolegomena; (III.) in section 49 of the Prolegomena; (IV.) in the second appendix to the Prolegomena; (V.) in sections added in the second edition at the conclusion of the Aesthetic (B 69 ff.); (VI.) in the “refutation of idealism” (B 274-8), in the supplementary section at the end of the section on the Postulates (B 291-4), and in the note to the new preface (B xxxix-xl); (VII.) in the “refutation of problematic idealism” given in the Seven Small Papers which originated in Kant’s conversations with Kiesewetter. Consideration of these in the above order will reveal Kant’s gradual and somewhat vacillating recognition of the new and revolutionary position which alone genuinely harmonises with Critical principles. But first we must briefly consider the various meanings which Kant at different periods assigned to the term idealism. Even in the Critique itself it is employed in a great variety of diverse connotations.

In the pre-Critical writings[993] the term idealism is usually employed in what was its currently accepted meaning, namely, as signifying any philosophy which denied the existence of an independent world corresponding to our subjective representations. But even as thus used the term is ambiguous.[994] It may signify either denial of a corporeal world independent of our representations or denial of an immaterial world “corresponding to” the represented material world, i.e. the denial of Dinge an sich. For there are traceable in Leibniz’s writings two very different views as to the reality of the material world. Sometimes the monads are viewed as purely intelligible substances without materiality of any kind. The{299} kingdom of the extended is set into the representing subjects; only the immaterial world of unextended purely spiritual monads remains as independently real. At other times the monads, though in themselves immaterial, are viewed as constituting through their coexistence an independent material world and a materially occupied space. Every monad has a spatial sphere of activity. The material world is an objective existence due to external relations between the monads, not a merely subjective existence internal to each of them. This alternation of standpoints enabled Leibniz’s successors to deny that they were idealists; and as the more daring and speculative aspects of Leibniz’s teaching were slurred over in the process of its popularisation, it was the second, less consistent view, which gained the upper hand. Wolff, especially in his later writings, denounces idealism; and in the current manuals, sections in refutation of idealism became part of the recognised philosophical teaching. Idealism still, however, continued to be used ambiguously, as signifying indifferently either denial of material bodies or denial of things in themselves. This is the dual meaning which the term presents in Kant’s pre-Critical writings. In his Dilucidatio (1755)[995] he refutes idealism by means of the principle that a substance cannot undergo changes unless it is a substance independent of other substances. Obviously this argument can at most prove the existence of an independent world, not that it is spatial or material. And as Vaihinger adds, it does not even rule out the possibility that changes find their source in a Divine Being. In the Dreams of a Visionseer (1766)[996] Swedenborg is described as an idealist, but without further specification of the exact sense in which the term is employed. In the inaugural Dissertation (1770)[997] idealism is again rejected, on the ground that sense-affection points to the presence of an intelligible object or noumenon.

In Kant’s class lectures on metaphysics,[998] which fall, in part at least, between 1770 and 1781, the term idealism is employed in a very different sense, which anticipates its use in the Appendix to the Prolegomena.[999] The teaching of the Dissertation, that things in themselves are knowable, is now described as dogmatic, Platonic, mystical (schwärmerischer) idealism. He still rejects the idealism of Berkeley, and still entitles it simply idealism, without limiting or descriptive predicates. But now also he employs the phrase “problematic{300} idealism” as descriptive of his own new position. This is, of course, contrary to his invariable usage elsewhere, but is interesting as showing that about this time his repugnance to the term idealism begins to give way, and that he is willing to recognise that the relation of the Critical teaching to idealism is not one of simple opposition. He now begins to regard idealism as a factor, though a radically transformed factor, in his own philosophy.

Study of the Critique reinforces this conclusion. In the Aesthetic Kant teaches the “transcendental ideality” of space and time; and in the Dialectic (in the fourth Paralogism) describes his position as idealism, though with the qualifying predicate transcendental.[1000] But though this involves an extension of the previous connotation of the term idealism, and might therefore have been expected to increase the existing confusion, it has the fortunate effect of constraining Kant to recognise and discriminate the various meanings in which it may be employed. This is done somewhat clumsily, as if it were a kind of afterthought. In the introductory syllogism of the fourth Paralogism Descartes’ position and his own are referred to simply as idealism and dualism respectively. The various possible sub-species of idealism as presented in the two editions of the Critique and in the Prolegomena may be tabulated as follows:

Idealism– Material Sceptical Problematic (the position of Descartes).
Sceptical in the stricter and more usual sense (the position of Hume).
Dogmatic (the position of Berkeley).
Formal or Critical or Transcendental (Kant’s own position).

The distinction between problematic idealism and idealism of the more strictly sceptical type is not clearly drawn by Kant.[1001] Very strangely Kant in this connection never mentions Hume: the reference in B xxxix n. is probably not to Hume but to Jacobi. Transcendental idealism is taken as involving an empirical realism and dualism, and is set in opposition to transcendental realism which is represented as involving empirical idealism. In B xxxix n. Kant speaks of “psychological idealism,” meaning, as it would seem, material or non-Critical idealism.{301}

In the second appendix to the Prolegomena Kant draws a further distinction, in line with that already noted in his lectures on metaphysics. Tabulated it is as follows:


Mystical, in the sense of belief in and reliance on a supposed human power of intellectual intuition. It is described as idealism in the strict (eigentlich) sense—the position of the Eleatics, of Plato and Berkeley.

Formal or Critical—Kant’s own position.

This latter classification can cause nothing but confusion. The objections that have to be made against it from Kant’s own critical standpoint are stated below.[1002]

Let us now consider, in the order of their presentation, the various refutations of idealism which Kant has given in his Critical writings.

I. Refutation of Idealism as given in First Edition of “Critique” (A 366-80).—This refutation is mainly directed against Descartes, who is mentioned by name in A 367. Kant, as Vaihinger suggests, was very probably led to recognise Descartes’ position as a species of idealism in the course of a re-study of Descartes before writing the section on the Paralogisms. As already pointed out, this involves the use of the term idealism in a much wider sense than that which was usually given to it in Kant’s own day. In the development of his argument Kant also wavers between two very different definitions of this idealism, as being denial of immediate certainty and as denial of all certainty.[1003] The second interpretation, which would make it apply to Hume rather than to Descartes, is strengthened in the minds of his readers by his further distinction[1004] between dogmatic and sceptical idealism, and the identification of the idealism under consideration with the latter. The title problematic which Kant in the second edition[1005] applies to Descartes’ position suffers from this same ambiguity. As a matter of fact, Kant’s refutation applies equally well to either position. The teaching of Berkeley, which coincides with dogmatic idealism as here defined by Kant, namely, as consisting in the contention that the conception of matter is inherently contradictory, is not dwelt upon, and the appended promise of refutation is not fulfilled.

Descartes’ position is stated as follows: only our own existence and inner states are immediately apprehended by us; all perceptions are modifications of inner sense; and{302} the existence of external objects can therefore be asserted only by an inference from the inner perceptions viewed as effects. In criticism, Kant points out that since an effect may result from more than one cause, this inference to a quite determinate cause, viz. objects as bodies in space, is doubtfully legitimate. The cause of our inner states may lie within and not without us, and even if external, need not consist in spatial objects. Further, leaving aside the question of a possible alternative to the assumption of independent material bodies, the assertion of the existence of such objects would, on Descartes’ view, be merely conjectural. It could never have certainty in any degree equivalent to that possessed by the experiences of inner sense.

“By an idealist, therefore, we must not understand one who denies the existence of outer objects of the senses, but only one who does not admit that their existence is known through immediate perception, and who therefore concludes that we can never, by way of any possible experience, be completely certain of their reality.”[1006]

No sooner is the term idealist thus clearly defined than Kant, in keeping with the confused character of the entire section, proceeds to the assertion (a) that there are idealists of another type, namely, transcendental idealists,[1007] and (b) that the non-transcendental idealists sometimes also adopt a dogmatic position, not merely questioning the immediacy of our knowledge of matter, but asserting it to be inherently contradictory. All this points to the composite origin of the contents of this section.

Transcendental idealism is opposed to empirical idealism. It maintains that phenomena are representations merely, not things in themselves. Space and time are the sensuous forms of our intuitions. Empirical idealism, on the other hand, goes together with transcendental realism. It maintains that space and time are given as real in themselves, in independence of our sensibility. (Transcendental here, as in the phrase “transcendental ideality,”[1008] is exactly equivalent to transcendent.) But such a contention is inconsistent with the other main tenet of empirical idealism. For if our inner representations have to be taken as entirely distinct from their objects, they cannot yield assurance even of the existence of these objects. To the transcendental idealist no such difficulty is presented. His position naturally combines with empirical realism, or, as it may also be entitled, empirical{303} dualism. Material bodies in space, being merely subjective representations, are immediately apprehended. The existence of matter can be established “without our requiring to issue out beyond our bare self-consciousness or to assume anything more than the certainty of the representations in us, i.e. of the cogito ergo sum.”[1009] Though the objects thus apprehended are outside one another in space, space itself exists only in us.

“Outer objects (bodies) are mere appearances, and are therefore nothing but a species of my representations, the objects of which are something only through these representations. Apart from them they are nothing. Thus outer things exist as well as I myself, and both, indeed, upon the immediate witness of my self-consciousness....”[1010]

The only difference is that the representation of the self belongs only to inner, while extended bodies also belong to outer sense. There is thus a dualism, but one that falls entirely within the field of consciousness, and which is therefore empirical, not transcendental. There is indeed a transcendental object which “in the transcendental sense may be outside us,”[1011] but it is unknown and is not in question. It ought not to be confused with our representations of matter and corporeal things.

From this point[1012] the argument becomes disjointed and repeats itself, and there is much to be said in support of the contention of Adickes that the remainder of the section is made up of a number of separate interpolations.[1013] First, Kant applies the conclusion established in the Postulates of Empirical Thought, viz. that reality is revealed only in sensation. As sensation is an element in all outer perception, perception affords immediate certainty of real existence, Kant next enters[1014] upon a eulogy of sceptical idealism as “a benefactor of human reason.” It brings home to us the utter impossibility of proving the existence of matter on the assumption that spatial objects are things in themselves, and so constrains us to justify the assertions which we are at every moment making. And such justification is, Kant here claims, only possible if we recognise that outer objects as mere representations are immediately known. In the next paragraph we find a sentence which, together with the above eulogistic estimate of the merits of idealism, shows how very{304} far Kant, at the time of writing, was from feeling the need of differentiating his position from that of subjectivism. The sentence is this:

“We cannot be sentient of what is outside ourselves, but only of what is in ourselves, and the whole of our self-consciousness therefore yields nothing save merely our own determinations.”

It is probable, indeed, that the paragraph in which this occurs is of very early origin, prior to the development of the main body of the Analytic; for in the same paragraph we also find the assertion, utterly at variance with the teaching of the Analytic and with that of the first and third Paralogisms, that “the thinking ego” is known phenomenally as substance.[1015] We seem justified in concluding that the various manuscripts which have gone to form this section on the fourth Paralogism were written at an early date within the Critical period.

We may note, in passing, two sentences in which, as in that quoted above, a distinction between representations and their objects is recognised in wording if not in fact.

“All outer perception furnishes immediate proof of something actual in space, or rather is the actual itself. To this extent empirical realism is beyond question, i.e. there corresponds to our outer perceptions something actual in space.”