Chapter 9 examines Kant’s critique of metaphysics in the Critique of Pure Reason. We discuss transcendental realism and its relation to transcendental idealism and then argue that rejecting transcendental realism does not presuppose transcendental idealism. Next, we will see that even on its most general level, Kant’s critique of metaphysics does depends not on transcendental idealism but on the much more specific claim that human cognition is limited to sensible objects. Finally, we will distinguish between different interpretations of Kant’s account of transcendental ideas and argue for a radical reading according to which, when viewed in a purely speculative context, ideas of reason fail to represent (really possible) objects, which accounts for the third level of Kant’s critique of metaphysics. Our result will be that Kant develops a challenging critique of speculative metaphysics that does not presuppose his transcendental idealism.