Virtue epistemologists hold that knowledge results from the display of epistemic virtues--open-mindedness, rigor, sensitivity to evidence, and the like. But epistemology cannot rest satisfied with a list of the virtues. What is wanted is a criterion for being an epistemic virtue. An extension of a formulation of Kant's categorical imperative yields such a criterion. Epistemic agents should think of themselves as, and act as, legislating members of a realm of epistemic ends: they make the rules, devise the methods, and set the standards that bind them. The epistemic virtues are the traits of intellectual character that equip them to do so. Students then not only need to learn the standards, methods, and rules of the various disciplines, they also need to learn to think of themselves as, and how to behave as, legislating members of epistemic realms who are responsible for what they and their fellows believe. This requires teaching them to respect reasons, and to take themselves to be responsible for formulating reasons their peers can respect. (Contains 8 notes.)