A central concept of Kant’s Critique of Judgment is that of a free play of imagination and understanding, associated with what he calls reflective judgments of beauty. “[I]t is precisely in this divorce from any constraint of a rule… where taste can show its greatest perfection in designs made by the imagination” (Hackett edition, p. 93). He also associates this with looking for a universal when we don’t already have one. (See also Searching for a Middle Term.)
This seems to be just what was missing from his account of ethical deliberation, reviewed in Kantian Maxims. It seems to me that the emergent synthesis of a unity of apperception must also involve something like this free play, and that ethical judgment should be considered as involving a whole unity of apperception. (See also Beauty, Deautomatization; Kant and Foundationalism; Kant’s Recovery of Ends; Truth, Beauty; Interpretation.)
Alongside the autonomy of reason, the notion of free play also seems to me to add a resource for nonvoluntarist readings of Kantian freedom.