Ordered Anarchy and Contractarianism

In a recent essay Robert Sugden sets out his view that two foundational institutions of the social order, the convention and the social contract (at least in one variant of the latter) are compatible and that therefore it is not self-contradictory to be a Humean and a contractarian at the same time.1 The proposition, despite appearances, has greater practical importance than most other doctrinal ones tend to do for if widely conceded, it would render current political thought even more woolly than it is already. If so, a critical scrutiny might be of some use.