  But what problem about the efficacy of the laws of freedom in the realm of nature could remain to be solved after the first two critiques? The Critique of Pure Reason had argued that although we can disprove the possibility of any breach in the determinism of the natural world and cannot have theoretical knowledge of the freedom of our will in the noumenal world, nevertheless we can coherently conceive of the latter. And the Critique of Practical Reason had argued that we can confidently infer the reality of our noumenal freedom to choose to do whatever morality requires of us from our immediate awareness of our obligation under the moral law combined with the principle that if we ought to do something then we must be able to do it (see Critique of Practical Reason, §6, 5:30, and Religion within the Boundaries of Mere Reason, 6:62, 66–7). The second Critique had also argued that since morality imposes an end upon us, namely that of realizing the highest good, the greatest happiness consistent with the greatest virtue, we must believe this to be possible, and thus must postulate “a supreme cause of nature having a causality in keeping with the moral disposition” (Critique of Practical Reason, Dialectic, 5:125; translation from Gregor, p. 240). If Kant has already established that on the basis of our awareness of our obligations under the moral law we can be confident that we have free will and that all of the laws of nature are at least consistent with our realization of the ends commanded by the moral law, what more needs to be done in order to throw a bridge between the theoretical cognition of nature and the laws of freedom?