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

by Norman Kemp Smith

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

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

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

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

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

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

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

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

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

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