In this chapter we return to Kant's origins in metaphysics in order to attempt to reactivate the real lines of tension between metaphysical and properly transcendental thought. In the main body of the chapter an assessment is given of the character of Kant's break with Leibniz. It has already been argued that Kant's critical project cannot be separated from metacritical issues, which in turn find vexed outlets in teleological issues. Now the claim will be that Kant's critical turn must be understood in relation to its transformation of Leibnizian rationalism. This claim will be gradually developed (and restricted) further throughout the book. Kant's ideas about the distinction between logic and reality are shown to originate in Leibnizian rationalism, while giving rise to a new conception of the ‘object’, which will form the centre of the new critical philosophy. In the following chapter, we will see how this new conception in turn results in a displacement of Leibnizian ideas about teleology and harmony to the ‘outer limits’ of Kant's philosophy, where we encounter again the difficulties of distinguishing critique from metaphysics, and critique from metacritique.

Kant's philosophy has an intimate relation with teleology throughout all of its phases. Bar his work on Spinoza, Deleuze's works on the history of philosophy – on Hume, Leibniz, Kant – are also characterised by the attention they give to teleology and the question of ‘ends’ or ‘purposes’. Usually, Leibniz is presented as the rationalist who upholds teleology, in the form of the pre-established harmony, while Hume is his sceptical foe, with Kant emerging out of the profound clash between these two outlooks.