Social Choice Theory, Game Theory, and Positive Political Theory

We consider the relationships between the collective preference and noncooperative game theory approaches to positive political theory. In particular, we show that an apparently decisive difference between the two approaches— that in sufficiently complex environments (e.g. high-dimensional choice spaces) direct preference aggregation models are incapable of generating any prediction at all, whereas non-cooperative game-theoretic models almost always generate prediction—is indeed only an apparent difference. More generally, we argue that when modeling collective decisions there is a fundamental tension between insuring existence of well-defined predictions, a criterion of minimal democracy, and general applicability to complex environments; while any two of the three are compatible under either approach, neither collective preference nor non-cooperative game theory can support models that simultaneously satisfy all