In his Transcendental Deductions of the categories, Kant purports to show that we have the right to employ our basic a priori concepts of a thing in general, e.g. the concept of causality, in cognition of the objects of experience. In Kant’s view, these concepts can thus be applied to observable phenomena. On the other hand, his Deductions deny us any cognition of things as they are in themselves, independently of our experience. These arguments ground not only his theoretical philosophy but his practical philosophy as well, in that they leave room for the possibility of freedom of the will. 

This dissertation presents a new elucidation of the Deductions by giving emphasis on Kant’s account of perceptual awareness. I argue that we can understand the Deductions by placing Kant’s account of perceptual awareness in its historical context. I show that Johann Tetens’ criticism of Christian Wolff’s account of perception had a crucial influence on Kant’s account, and that by giving attention to this influence we can understand the design of the Deductions, which establish the objective validity of the categories to objects of experience by showing that perceptual awareness is possible only through the same a priori rules that are represented generally in the categories.