“Hume dwelt especially upon the principle of causality, and quite rightly observed that its truth, and even the objective validity of the concept of efficient cause in general, is based on no insight, _i.e._ on no _a priori_ knowledge, and that its authority cannot therefore be ascribed to its necessity, but merely to its general utility in the course of experience and to a certain subjective necessity which it thereby acquires, and which he entitles custom. From the incapacity of our reason to make use of this principle in any manner that transcends experience he inferred the nullity of all pretensions of reason to advance beyond the empirical.” Now so far, in these references to Hume, Kant has had in view only the problems of mathematical and physical science and of metaphysics. The problems involved in the possibility of empirical knowledge are left entirely aside. His account of Hume’s position and of his relation to Hume suffers change immediately these latter problems are raised. And unfortunately it is a change for the worse. The various problems treated by Hume are then confounded together, and the issues are somewhat blurred. Let us take the chief passages in which this occurs. In A 764 = B 792 ff. Kant gives the following account of Hume’s argument. Hume, recognising the impossibility of predicting an effect by analysis of the concept of the cause, or of discovering a cause from the concept of the effect, viewed all concrete causal judgments as merely contingent, and therefrom inferred the contingency of the causal axiom. In so doing Hume, Kant argues, confuses the legitimate and purely _a priori_ inference from a given event to _some_ antecedent with the very different inference, possible only through special experience, to a _specific_ cause. Now this is an entire misrepresentation of Hume’s real achievement, and may perhaps be explained, at least in part, as being due to the fact that Kant was acquainted with Hume’s _Treatise_ only through the indirect medium of Beattie’s quotations. Hume committed no such blunder. He clearly recognised the distinction between the problem of the validity of the causal axiom and the problem of the validity of concrete causal judgments. He does not argue from the contingency of concrete causal laws to the contingency of the universal principle, but shows, as Kant himself recognises,[258] that the principle is neither self-evident nor demonstrable _a priori_. And as necessity cannot be revealed by experience, neither is the principle derivable from that source. Consequently, Hume concludes, it cannot be regarded as objectively valid. It must be due to a subjective instinct or natural belief. (The two problems are similarly confounded by Kant in A 217 = B 264.)