Kant's concept of autonomy promises to solve the problem of the actuality offreedom. The latter has actuality as a practical capacity insofar as the will is objectively determined through the form of law. In later writings, however, Kant situates the actuality of freedom in the "absolute spontaneity" of choice, and connects the reality of autonomy itself to the condition of a "radical" act of free choice. The reason for this resides in the fact that his first solution is marked by a certain defect: it does not contain a sufficient concept of the actuality of a practical capacity. This essay elaborates a revised account of Kant's concept of freedom in light of this insight. The argument is that we need to distinguish force and faculty in order to understand the actuality of a capacity. Only on this basis can we introduce the idea of imagination as a pre-reflexive force of practical reason and the idea of reflective judgment as a power of practical judgment in order to realize how free choice is capable of generating a maxim that has the form of a law spontaneously and of its own accord. In this way, we see that the actuality offreedom necessarily includes the spontaneity of choice, and that human freedom manifests a certain paradoxicality: the universality of the will is bound to a subjective ground of determination, to a pre reflexive act of "radical" choice.