In recent years, various ethical theorists have turned to considering the nature of rationality.' How, after all, might we best seek out a promising line of approach to fundamental moral questions? A possible stratagem is to ask first why moral questions matter. The chief reasons must surely lie in what their answers can tell us of how to live-and in this response may lie hints of a way to proceed. Look for what, in a general prescription for living, plays the role of morality and take that itself to constitute morality. Deciding how to live, after all, is in effect deciding how it is rational to live. Begin, then, by developing a theory of rational conduct, and then in that theory, see if there is anything that fits our ordinary, vague picture of the demands of morality. If there is, call that moralityfor whether or not it is what we initially conceived morality to be, it is what we can rationally treat in much the way we initially treated morality in our thinking. This broad approach evidently requires a theory of rational conduct. What does it mean for something to be "rational"? To call a thing "rational" is to endorse it in some sense, and that in turn suggests a scheme for eliciting the meaning of 'rational.' Instead of seeking to define a property, "rationality," by giving the conditions under which a thing would have that property or lack it, start with the use of the term. Fix on the dictum