In Section 2.1 we saw that Hume and Kant have differing conceptions of knowledge, since the former grants all epistemic authority to the givenness of sense experience and the latter insists upon an a priori synthesis to render sense experience intelligible, while both nevertheless conceive of objects of knowledge as materially constituted by sense experience. These similarities and differences are epitomized in Bhaskar's observation that for both the Humean and the Kantian versions of empirical realism, a constant conjunction of events is a necessary condition for a causal law (such that nature as known by science partly consists of regularly sequential perceptual events) and that empiricism and transcendental idealism just part ways at the question of what constitutes the sufficient conditions. However, that transcendental idealism actually is so committed to constant conjunctions of events is not as immediately obvious as Bhaskar's quick and casual references to Kant would have us believe, given the complexity of the transcendental idealist account of the representation of an objective causal connection. In this chapter, therefore, I will provide an exposition of Kant's conception of natural necessity with a view to demonstrating its commitment to constant conjunctions of events, its transformation of the ontological concept of causality into a purely epistemological one, and its corresponding disallowance of real causal powers in nature.