ABSTRACT
Impossibility theorems rest on several assumptions, each of which has been the subject of extensive debates. The one assumption that is not even explicitly mentioned is that individual preferences are given and remain unchanged during the political process. Viewed from the perspective of economics, the political process consists only of revealing and aggregating exogenously formed individual preferences. Yet it is conceivable that individuals change their preferences as the result of communicating with one another [Sen, 1977; Offe and Wiesenthal, 1980; Elster, 1984; Kolm, 1984]. Unfortunately, we do not have a reasonable description of the way in which preferences change. Riker [1982: p. 122 and p. 128J admitted the possibility that political interactions may modify voter preferences but on unspecified grounds he relegated this possibility to issues that are not politically important. The central issue is whether transitive collective preferences could be induced by a political process in which politicians would deliberately seek to produce an unambiguous and consistent mandate. At this stage, no one seems to know.
