The Propositions of Freedom : On Kant’s Distinction between the Moral Law and the Practical Postulate

In the Critique of Practical Reason, Immanuel Kant provides two different propositions of freedom. According to the first, in the “Analytic of Pure Practical Reason,” freedom establishes the possibility of moral agency—i.e., it is the ratio essendi of the moral law. According to the second, in the “Dialectic of Pure Practical Reason,” freedom is the object of one of the practical postulates (CPrR 246–54; AA 5:132–41). Why should Kant postulate something that has been allegedly established as the ground of moral agency? Does Kant appeal to two different conceptions of freedom? In this paper, I argue that Kant (1) in both cases conceives of freedom as an unconditioned form of causality, and (2) pursues two different aims according to two different but complementary arguments. On the one hand (the practical standpoint), he wants to argue that the causality of freedom is actual, through moral agency, in the domain where the laws of nature also apply. On the other hand (the theoretical standpoint), he is aware that the possibility of achieving the highest good would be compromised if we did not assume, along with the other two postulates, a world in which only the causality of freedom applies. While freedom as the ratio essendi of the moral law is actual, freedom as a postulate is a mere object of belief.

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