Scepticism is the second approach to metaphysics that Kant considered an alternative to his ‘critical’ investigation. It is David Hume who plays the role of the paradigmatic representative of this viewpoint. I begin by analyzing three different readings of Kant’s understanding of Hume’s scepticism about causality. Hume’s scepticism is seen as posing a challenge to natural science and ordinary knowledge, as a problem that puts into question the possibility of general metaphysics, or as a ‘dialectical’ form of scepticism primarily directed against special metaphysics. I suggest that the first reading is implausible. I argue that the second and third readings are compatible once one distinguishes between the perspectives of transcendental philosophy and the critique of pure reason, respectively. Finally, I show that one objection that has been raised against the third reading can be silenced if we interpret Kant’s reading of Hume from the standpoint of his history of pure reason.

Chapter 3 addresses the relationship between the various tasks carried out in the Critique of Pure Reason by analyzing Kant’s multifaceted use of the term ‘transcendental.’ Challenging the received view, it maintains that Kant’s seemingly divergent accounts of the subject hinge on his conception of transcendental philosophy proper and transcendental critique as first-order and second-order branches of transcendental cognition, respectively. Drawing on a brief account of the seventeenth- and eighteenth-century history of the term ‘transcendental,’ the chapter seeks to show that Wolffian ontology and transcendental philosophy proper have more in common than is widely assumed: both disciplines can be said to provide a comprehensive account of the cognitive elements presupposed in any cognition of objects. On this account, the novelty of the Critique consists primarily in the second-order investigation into metaphysics that Kant calls transcendental critique. The chapter concludes by examining Kant’s criticism of the way his predecessors and contemporaries understood the terms ‘ontology’ and ‘transcendental philosophy.’