Kant's Conception of Practical Reason

My dissertation develops a novel account of Kant's moral philosophy by focusing on his conception of pure reason. As is well known, Kant contends that morality has its source in pure reason, and that the authority of moral considerations derives from this source. Yet recent commentators have shied away from Kant's account of reason, emphasizing instead aspects of his view that seem to make it more accessible. In particular, influential constructivist readings have stressed the role of rational agents as autonomous subjects that "construct" the principles or values they commit themselves to. I argue that to properly grasp Kant's distinctive conception of moral constraints, and his conception of rational agency, we must look to his underlying account of reason.My dissertation divides into two parts. In the first part, I reconstruct Kant's account of the practicality of pure reason, i.e. reason's capacity to determine the will a priori, and show how all norms of practical reason are systematically derived from this capacity. In particular, I show: (1) that all possible moral constraints derive from pure reason's determination of the will and that each such constraint must be systematically related to all the others; and (2) that the norms of instrumental rationality equally depend on reason's capacity to determine the will a priori. In the second part, I broaden the focus to consider the relations between the theoretical and practical exercises of reason. I develop the formal parallels between the two exercises of reason and show how each exercise is governed by a corresponding rational interest. I then elaborate Kant's notion of a rational interest to show that for Kant reason is fundamentally practical—in the sense that reason's theoretical exercise is in important respects shaped by its practical concerns. A key upshot of this argument is that we cannot fully grasp Kant's account of practical reason unless we consider the relation between theoretical and practical reason. Once we consider this relation, however, we see that Kant takes morality, i.e. reason's legislation of the moral law, to be the grounding principle of all rational activity