The Unity of Reason: Kant’s Copernican Presupposition

In the controversial Appendix to the Transcendental Dialectic, Kant claims to “complete the critical work of pure reason” [A670/B698] by providing a transcendental deduction of the ideas of pure reason. In order to analyse the role that this Appendix plays in the first Critique, this paper will read the Appendix alongside Kant’s comments in the B-Preface concerning the astronomy of Copernicus. Through an analysis of the nature of Kant and Copernicus’ respective use of presuppositions, and by looking at their respective attempts to unify a science around a single systematic conception of the object of that science, this paper will offer a defence of the fundamental role that Kant’s transcendental deduction of the ideas of pure reason plays in the text.