Kant's contributions to our understanding of the mind came largely in the course of pursuing other projects. The Critique of Pure Reason was intended to determine what we can know. In trying to answer that question Kant was led to consider what minds must be like to be capable of knowledge. His search for a sound basis for ethics included an investigation of the nature of a being who could be a morally responsible agent. He offered hypotheses about how observers appreciate beauty and sublimity in order to clarify the significance of the aesthetic appreciation of art and nature. By investigating what we could do or what he thought we could do, he developed theories about who or what we are.

The task of integrating the aspects of mind that Kant believed are required for knowledge, morality, and aesthetic sensibility in a consistent portrait of a subject has yet to be carried out. In this chapter, I focus exclusively on his depictions of the mind as a subject of knowledge in the Critique of Pure Reason. His theory of the active cognizer stands behind his most arresting philosophical doctrine, namely, the thesis that “we ourselves bring into the appearances that order and regularity in them that we call nature, and moreover we would not be able to find it there if we, or the nature of our mind, had not originally put it there” (Pure Reason, A 125).