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

by Norman Kemp Smith

“...without it we should have no Reason at all, and without Reason no coherent employment of the understanding, and in the absence of this no sufficient criterion of empirical truth. In order, therefore, to secure an empirical criterion we are absolutely compelled to presuppose the systematic unity of nature as objectively valid and necessary.”[1650] “It might be supposed that this is merely an economical contrivance of Reason, seeking to save itself all possible trouble, a hypothetical attempt, which, if it succeeds, will, through the unity thus attained, impart probability to the presumed principle of explanation. But such a selfish purpose can very easily be distinguished from the Idea. For in the latter we presuppose that this unity of Reason is in conformity with nature itself; and that, although we are indeed unable to determine the limits of this unity, Reason does not here beg but command.”[1651]

This last alternative, that Reason is here propounding a tentative hypothesis, in order by trial to discover how far it can be empirically verified—an alternative which Kant in the above passage rejects as unduly subjective, and as consequently failing to recognise the objective claims and a priori authority of the Ideas of Reason,—is yet a view which he himself adopts and indeed develops at considerable length in this same section. This, as already stated, affords evidence of the composite character and varying origins of the material here presented.

The Dissertation of 1770 gives a purely subjectivist interpretation of the regulative principles, among which, from its pre-Critical standpoint, it classes the principle of causality and the principle of the conservation of matter.

”[We adopt principles] which delude the intellect into mistaking them for arguments derived from the object, whereas they are commended to us only by the peculiar nature of the intellect, owing to their convenience for its free and ample employment. They therefore ... rest on subjective grounds ... namely, on the conditions under which it seems easy and expeditious for the intellect to make use of its insight.... These rules of judging, to which we freely submit and to which we adhere as if they were axioms, solely for the reason that were we to depart from them almost no judgment regarding a given object would be permissible to our intellect, I entitle principles of convenience.... [One of these is] the popularly received canon, principia non esse multiplicanda praeter summam necessitatem, to which we yield our adhesion, not because we have insight into causal unity in the world either by reason or by experience, but because we seek it by an impulse of the intellect, which seems to itself to have advanced in the explanation of phenomena only in the degree in which it is granted to it to descend from a single principle to the greatest number of consequences.”[1652]

This, in essentials, is the view which we find developed in A 646-9 = B 674-8. Reason is the faculty of deducing the particular from the general. When the general is admitted only as problematical, as a mere idea, while the particular is certain, we determine the universality of the rule by applying it to the particulars, and then upon confirmation of its validity proceed to draw conclusions regarding cases not actually given. This Kant entitles the hypothetical use of Reason. Reason must never be employed constitutively. It serves only for the introduction, as far as may be found possible, of unity into the particulars of knowledge. It seeks to make the rule approximate to universality.[1653] The unity which it demands

“...is a projected unity, to be regarded not as given in itself, but as a problem only. This unity aids us in discovering a principle for the manifold and special employment of the understanding, drawing its attention to cases which are not given, and thus rendering it more coherent.”[1654]

The unity is merely logical, or rather methodological.[1655] To postulate, in consequence of its serviceableness, real unity in the objects themselves would be to transform it into a transcendental principle of Reason, and to render

“...the systematic unity necessary, not only subjectively and logically, as method, but objectively also.”[1656]

The above paragraphs are intercalated between A 645 = B 673 and A 650-63 = B 678-91, in which, as we have already seen, the directly opposite view is propounded, namely, that such principles are not merely hypothetical, nor merely logical. In all cases they claim reality, and rest upon transcendental principles; they condition the very possibility of experience; and may therefore be asserted to be a priori necessary and to be objectively valid. To quote two additional passages: