In the previous chapter of the transcendental analytic Kant presented the pure forms of understanding through the table of judgements and the table of categories. In this chapter, he must show how it can be that these forms can actually be applied to objects of experience. He refers to this project as transcendental deduction, that is, an explanation of the necessary way in which concepts are integral to the presentation of objects in human experience.

For Kant, experience is constituted by two very different elements: matter and form. Matter is provided to the mind through the receptive faculty of sensibility and form is applied to the matter “from the inner source of pure intuition and thought,” i.e., understanding. Though we have investigated both sensibility and understanding, we as yet have no idea how these two can be combined to create experience. Kant stresses the importance of discovering and deducing the source of this combination (synthesis). The problem is a difficult one: “how subjective conditions of thought could have objective validity, i.e., how they could yield conditions for the possibility of all cognitions of objects” (145).