There is a tradition in western ethics in which use of the concept of right reason is explicit and central. I sketch its history and then formulate six theses affirmed by its spokesmen. In light of the resulting definition I contend that an ethics of right reason is essentially maintained by a variety of moral philosophers in addition to those usually thought to be in the tradition. Its central idea is just that reason in a certain (right) state sets or (...) discovers the standard of right, Wrong, Virtue and vice, But both reason and its right state may be variously conceived. (shrink)