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.

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 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 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 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.

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.

4. PHENOMENALISM, KANT’S SUBSTITUTE FOR SUBJECTIVISM

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 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 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.

5. THE DISTINCTION BETWEEN HUMAN AND ANIMAL INTELLIGENCE

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 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 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:

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.

6. THE NATURE AND CONDITIONS OF SELF-CONSCIOUSNESS

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 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, 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.

7. KANT’S THREEFOLD DISTINCTION BETWEEN SENSIBILITY, UNDERSTANDING, AND REASON

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, 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 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 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.

8. THE PLACE OF THE CRITIQUE OF PURE REASON IN KANT’S PHILOSOPHICAL SYSTEM

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 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.

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.

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.

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 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.

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.

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 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 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.