Kevin Quinn lays out what makes sense (to me) very well. There's a trade-off in assertions of individual rationality. One can imagine the possibility of a totally tautological concept of rationality: John Wayne Gacy, say, has a preference for inconsistent behavior, since he likes spontaneity, surprise, and serendipity. Therefore even the consistency definition ends up being circular. But one could add "constraints on the interpretations of preferences" which allow falsification and admit the possibility of irrationality. Of course, that means that the concept might be rejected (as, I am told, psychologists have rejected behaviorism). I think that a lot of economists play a disingenuous game: they take a non-tautological version of rationality, i.e., one that assumes that people are atomistically individualistic with fixed tastes -- and all sorts of convenient ideological overtones, since this sociopathic behavior is seen as "rational," in some sense good -- but THEN defend this concept and its ideological content by invoking the tautological version. in pen-l solidarity, Jim Devine [EMAIL PROTECTED] or [EMAIL PROTECTED] Econ. Dept., Loyola Marymount Univ., Los Angeles, CA 90045-2699 USA 310/338-2948 (daytime, during workweek); FAX: 310/338-1950 "Who'll stop the rain?" -- John Fogarty.