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

by Norman Kemp Smith

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

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

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

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

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

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

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

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

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

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