  Although Immanuel Kant rarely uses the term ‘transcendental argument’, and when he does it is not in our current sense (cf. Hookway 1999: 180 n. 8), he nonetheless speaks frequently of ‘transcendental deductions’, ‘transcendental expositions’, and ‘transcendental proofs’, which roughly speaking have the force of what is today meant by ‘transcendental argument’. Prior exemplars of such arguments may perhaps by claimed, such as Aristotle’s proof of the principle of non-contradiction (see Metaphysics 1005b35–1006a28; Illies 2003: 45–6, Walker 2006: 240 and 255–6); but Kant nonetheless formulated what are generally taken to be the central examples of such arguments, so the history of the topic is usually assumed to start here, with the Critique of Pure Reason and its Transcendental Deduction of the Categories, Second Analogy, and Refutation of Idealism. Briefly put, the Deduction is directed against skepticism concerning the applicability of a priori concepts to our experience; the Second Analogy concerns doubts over causal powers or forces; while the Refutation of Idealism focuses on our apparent lack of knowledge concerning the existence of the external world.