To advance a successful reading of Kant's theory of motivation, his interpreter must have a carefully developed position on the relation between our rational and sensible capacities of mind. Unfortunately, many of Kant's commentators hold an untenably dualistic conception, understanding reason and sensibility to be necessarily conflicting aspects of human nature that saddle Kant with a rigoristic and fundamentally divided moral psychology. Against these interpreters, I argue for a reading that maintains a unified conception, claiming that we must think of (...) reason and sensibility as interdependent capacities, which stand to one another as form to matter. Our sensible nature thus does not stand opposed to reason; its fundamental character is determined by reason's activity. I take Kant's account of moral motivation and the feeling of respect to represent the lynchpin of this unified account. Against interpreters who would emphasize either the intellectual or affective nature of respect, I claim that it should be understood as the formal element of moral sensibility, the result of practical reason determining the capacity to feel and fundamentally transforming its character. To make this argument, I draw on Kant's account of sensibility in the Critique of Pure Reason, claiming that space, time, and respect for the moral law are analogous formal elements of sensibility. (shrink)