Although Kant sees the source of the basic concepts of our knowledge in understanding, it is still unclear whether he meant our capacity for thought or the totality of our epistemological powers. The author attempts to clarify the matter with an analysis of the pre-critical writings and the Critique of Pure Reason. In addition, he elucidates the system of these concepts.

The author sets himself off against other interpreters, who place the source of the categories in the unity of apperception (like the post-Kantian idealists, Cohen, Henrich etc.) or in the imagination as the root of all ability (Heidegger) and then ascribe these doctrines to Kant himself. Rosales develops the system of these concepts from the relationship of apperception to imagination, and methodically distinguishes between his attempt as an independent development of Kantian potential and the philosopher's own work.