“Kant, like the [moral] realist, thinks we must show that particular actions are right and particular ends are good. Each impulse as it offers itself to the will must pass a kind of test for normativity before we can adopt it as a reason for action. But the test that it must pass is not the test of knowledge or truth. For Kant, like Hume and Williams, thinks that morality is grounded in human nature, and that moral properties are projections of human dispositions. So the test is one of reflective endorsement.”

– Christine M. Korsgaard, The Sources of Normativity