Contractarianism is the theory that models or evaluates social interaction on the basis of a social contract. Whether one tends to agree or disagree with this approach, it is important to understand it. In my review of Geoffrey Brennan and James Buchanan’s The Reason of Rules, just out on Econlib, I note:

The classical liberal contractarianism elaborated in The Reason of Rules presents a big challenge to both the anarchist, who thinks that the state cannot be beneficial to everybody, and the statist, who believes that it must be run by some enlightened elite, numerical majorities, or populist movements.

The commenters who engaged with my EconLog posts on Buchanan’s theories may want to read the book or at least my review. Two more short excerpts of the latter, which of course doesn’t do justice to this complex but fascinating topic:

A fundamental component of the contractarian theory defended in The Reason of Rules is that the basic rules of human interaction must be agreed upon unanimously, by all individuals. The social contract is the set of these basic rules. Individuals would have little hope of agreeing on actual outcomes (think about agreeing on the actual distribution of income or other advantages), but they all have an interest in agreeing on the rules of the social game, the general rules that will guide social interactions among individuals each pursuing his own self-interest.

Brennan and Buchanan emphasize how the contractarian approach radically differs from non-contractarian views. In a contractarian perspective, politics is the search for what every individual wants. In the non-contractarian view, “the good” is something external to individuals and politics becomes a search for it, analogous to the search for truth in science. In the best case, “[t]hose who disagree with the definition of the ‘good’ are misinformed and in error.” In the worst case, the supposed “good” is imposed by a benevolent despot, democratic or not.