Abstract

This thesis is about Kant’s account of reason. In the Critique of Pure Reason, Kant introduces reason as an infinitely demanding faculty that seeks complete explanations for all observable phenomena. This account of reason is essential to Kant’s discussion in the Transcendental Dialectic and prompts the primary question of this thesis: how does Kant justify such an infinitely demanding faculty? How does he think we come to know that we have reason, so understood? Traditionally, Kant scholars have held that we can grasp our mental faculties either through a priori awareness of their unique activities or through transcendental arguments. Both approaches, however, fail with reason, which presents unique metacritical challenges. We can never be aware of reason’s unique activities, which are infinite and so never complete, and reason cannot be established via transcendental argument because it is not necessary for the possibility of experience. So, how can we know that we have reason? This thesis breaks with tradition by arguing that reason gains self-knowledge in empirical psychology, the study of phenomena in inner sense. Reason, according to Kant, seeks to explain all phenomena, including those of inner sense. To explain inner phenomena, reason hypothesises mental faculties and their laws. Our tendency to ask why-questions, Kant argues, is best explained by hypothesising a faculty that demands complete explanations – i.e., reason. The thesis has five chapters. The first shows that, for Kant, mental faculties are (also) powers of inner sense. The second argues that the normative demands of these faculties are grounded in constitutive principles or laws. The third finds that the constitutive principle of reason requires us to systematise powers of nature, which, as the fourth chapter explains, we do by hypothesising their respective laws. Finally, the fifth chapter suggests that reason hypothesises its own explanation-seeking law.