A Critical Exposition of the Concept of Hume’s Substance and Its Impact on Kant’s Theory of Knowledge

In this article with a study of the meaning of substance in empirical philosophers’ viewpoints, we show that Hume's negation of substance has influenced Kant's theory of knowledge. To solve the problem of knowledge, Kant, on the one hand, turns the substance negated by Hume into a thing in itself. In this way, he tries to provide a strong foundation for the phenomena and keep his philosophy from falling into the abyss of absolute idealism. On the other hand, with the Copernican revolution, he turned the substance into one of the categories and determinations of the subject. In this way, he kept its essential role in the formation of knowledge and paved the way for the object to correspond with the mind. Therefore, in a sense, Kant preserves the substance in the meaning of the predecessors, but no epistemic role is possible for this meaning; however, he tries to maintain the epistemic position of the substance in another sense. The reason why Kant, while transforming the substance of the predecessors into a thing in itself, did not abandon the substance, but presented another definition of it, was to be able to explain perception. Because he needed a permanent thing, of course, a permanent thing that can be pointed to its position with the subject, not an unchanging existence that is unknown with the objects.