Abstract

The possibility of cooperation and the stability of political order are long-standing problems. Polybius, well known for his Histories analysing the expansion of Rome and his description of the Roman constitution, also offers an intriguing social and political theory that covers ground from psycho-anthropological micro-foundations to institution-based political order, providing a genealogy of morals and political order that is best understood in game-theoretical terms. In this paper I try to give such an interpretation. Polybius’ naturalistic, proto-game theoretical views show similarities with Hume, Smith and especially Hobbes’ doctrine of sovereignty by acquisition. However, Polybius is original in crucial regards, giving a motivationally plausible account of institutional and especially constitutional solutions to moral and political problems. Constitutional order, for Polybius, embodies and makes possible in the first place a kind of political reason that cannot be had individually. Polybian political theory thus offers interesting solutions to problems concerning moral motivation, collective action, and the conditions for political order, as well as the explanation and character of institutions.