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

by Norman Kemp Smith

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]