In 1792 and 1798 Kant noticed two basic problems with hisMetaphysical Foundations of Natural Science (MAdN) which opened a crucial gap in the Critical system as a whole. Why is theMAdN so important? I show that the Analogies of Experience form an integrated proof of transeunt causality. This is central to Kant's answer to Hume. This proof requires explicating the empirical concept of matter as the moveable in space, it requires the specifically metaphysical principle that every physical event has an (...) external cause, and it requires a metaphysical principle regarding the individuation of spatio-temporal things. These three doctrines are not defended in the firstCritique, but only in theMAdN. Kant's transcendental analysis of the conditions of experience thus requires the special metaphysics of theMAdN. This marks an important shift in Kant's view of the metaphysical basis of the transcendental philosophy. (shrink)