 Hume’s position on the deducibility of a priori metaphysical concepts is Kant’s quarry in the Transcendental Deduction. But Kant concurs with Hume’s proposal that no empirical deduction can be supplied for such concepts. Instead, he sets out to provide a different sort of justification for their use, one that is transcendental rather than empirical. Such a transcendental deduction begins with a premise about any possible human experience, a premise to which reasonable participants in the debate can be expected initially to agree, and then contends that a presupposition and necessary condition of the truth of that premise is the applicability of the a priori concepts in question to the objects of experience. Kant’s Transcendental Deduction features a number of component transcendental arguments. Each begins with a premise either about the self-attributability of mental items, apperception, or else a premise about the necessity and universality of some feature of our experience of objects. Kant’ strategy is to establish a theory of mental processing, synthesis, by arguing that its truth is a necessary condition for the truth of such a premise, and then to show that the a priori concepts at issue – the categories – have an essential role in this sort of mental processing. On a metaphysical idealist interpretation of his position, the objects of experience result from this mental processing, and it is due to the role that the categories have in this processing that they correctly apply to objects. In the Transcendental Deduction Kant would thus intend to secure a normative claim, that the categories correctly apply to the objects of our experience, by establishing a psychological theory (Henrich 1989; Patricia Kitcher 1990: 2–29; for information on related argumentative strategies in Kant’s historical context, see Kuehn 1997 and Dyck 2011). The Transcendental Deduction presents general considerations supporting the applicability of all the categories to the objects of our experience; it does not concentrate on the applicability of specific categories. This more focused task is taken up in various sections of the Analytic of Principles (A130–235/B169–287).