“There are in our tradition two things which philosophers have meant by “reason”. “Reason” refers to the active as opposed to the passive capacities of the human mind, and “reason” also refers to certain sets of principles — logical principles, moral and other practical principles, and the principles that Kant associates with the pure concepts of the understanding. What Kant did, as I see it, was to try to bring these two conceptions of reason together: to explain the normative force of the principles by showing that they are constitutive of reflective mental activity itself. To choose is to follow the hypothetical and categorical imperatives; to understand is to employ the concepts and principles of the understanding, and so on. And in the same way, my own aim is to portray moral principles as constitutive of, and so as essential to, making human choices, and leading a human life.”

– Christine M. Korsgaard, The Sources of Normativity