Philosophers, psychiatrists, and social scientists would welcome clarification of the distinction between rational and irrational desires. It may be proper to say that rational desires are those which manifest rationality. But since this seems a rather unilluminating characterization, philosophers sometimes offer definitions of what constitute such manifestations of rationality. I shall consider definitions provided by John Rawls and Richard Brandt. Their definitions are unsatisfactory mainly because they include subjunctive conditionals. An alternative approach, which avoids conditionals, is attractive. But it encounters (...) so many additional problems that I shall conclude that we are not now in a position to define rationality in this area and must treat it as a state or disposition which to date has only been partially characterized. Thus, if we want a definition of the difference between rational and irrational desires, we must at present settle for the rather unexciting one mentioned above. (shrink)