 Kant thus has a completely different perspective from Hume’s concerning the uniformity of nature. For Hume, the principle of uniformity is a supposition implicit in all of our inductive inferences leading to the formulation of laws of nature. If this principle itself had a foundation in the understanding (in either a priori or a posteriori “reasoning”), then so would our inductive inferences from observed constant conjunctions to so far unobserved events. Yet the supposition in question—“that instances, of which we have had no experience, must resemble those, of which we have had experience, and that the course of nature continues always uniformly the same” (T 1.3.6.4; SBN 89)—cannot itself be justified by either demonstrative or inductive reasoning. In the former case it would have to be self-contradictory to imagine that the course of nature is not sufficiently uniform; in the latter the attempted justification would be viciously circular. The principle of uniformity, however, is firmly based in custom or habit, as a universal principle of the human mind, and it is also the foundation for the Newtonian inductive method—including Hume’s own inductive science of the human mind. Although the principle thus has normative force in all our reasoning concerning matters of fact in both science and common life, it cannot ultimately legitimate the attribution of objective necessity to our inductively established laws of  nature.[50]