Chapter V: Introduction: I. Textual (1)

KANT’S METHOD OF COMPOSING THE ‘CRITIQUE OF PURE REASON’

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 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, 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 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 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-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.

II. HISTORICAL

KANT’S RELATION TO HUME AND TO LEIBNIZ

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 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 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 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 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.

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 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 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 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]

III. GENERAL

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_.

I. THE NATURE OF THE _A PRIORI_

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 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 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 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.

2. KANT’S CONTRIBUTION TO THE SCIENCE OF LOGIC

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 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 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 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.

3. THE NATURE OF CONSCIOUSNESS

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 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 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.