This article attempts to assess Jon Elster's contribution to rational choice in Ulysses and the Sirens and Sour Grapes. After reviewing Elster's analysis of functional versus intentional explanations, the essay moves on to the crucial distinction between the thin and broad theories of rationality. The former elabo rates on the traditional economist's preference / feasible set apparatus; the latter is the more demanding theory which inquires into the rationality of beliefs and preferences. Elster's approach to the broad theory normally consists (...) in using the thin theory as a reference point and in making purposefully limited departures from it. The essay illustrates the method while commenting on Elster's discus sion of autonomous preferences in Sour Grapes. It goes on to stress some impor tant analogies between Elster's use of the thin and broad theories, on one hand, and Weber's ideal-typical method, on the other. The final assessment is phrased in terms of these analogies; it is suggested that Elster is at his best when the ideal-typical method and his own separate from each other, that is, when he comes to grips with the broad theory in its own terms. (shrink)