IX-the transcendental deduction of ideas in Kant's Critique of Pure Reason

This article explores the problem of the transcendental deduction of ideas in the controversial pages of the Appendix to the Transcendental Dialectic of Kant's Critique of Pure Reason. It suggests that Kant's difficulties with the deduction can be explained in light of a tension between two notions of purposiveness: purposiveness as design and purposiveness as normativity. While the latter is shaped by the practical demands of reason, the former relies on an argument about the teleological structure of nature. The article further shows that although the Critique of Pure Reason tries to ground the unity of reason in a notion of purposiveness as normativity, it lacks the resources to do so. The result is an attempt which collapses the demand for the unity of reason into a demand for the unity of nature, and which grounds the unity of nature on a notion of purposiveness as design. This outcome challenges not only Kant's unifying project but the success of the entire critical enterprise. Explaining how it unfolds by considering Kant's analysis in the first Critique, and in minor writings of the same period, provides the most textually accurate account of Kant's oscillations in the Appendix, whilst also doing justice to its future developments.