INTRODUCTION

Liberals have often been attracted by contractarian modes of argument– and with good reason. Any system of social organization requires that some constraints be imposed on individuals' freedom of action; it is a central problem for any liberal political theory to show which constraints can be justified, and which cannot. A contractarian justification works by showing that the constraints in question can be understood as if they were the product of an agreement, voluntarily entered into by every member of society. Thus, no one is required to give up his freedom for someone else's benefit, or in the pursuit of someone else's conception of the social good.

Contractarian arguments fit well with a Humean account of the primacy of passion over reason. From a Humean point of view, there are no ends–whether for the individual or for society as a whole–that are prescribed by reason. There are only desires. Thus, if we are to justify a constraint to the person who is to be constrained, we need to show that in some way the constraint helps him to satisfy his own desires. Contractarian arguments do this by showing that each person's acceptance of certain constraints is a necessary part of a social scheme whose general tendency is to satisfy everyone's desires. In this essay, I shall work within a Humean framework, taking it as given that there are no rationally prescribed ends.

This essay identifies a general problem in contractarian theory. The usual strategy for showing that everyone could agree to a particular set of rules is to show that, over the long run, those rules can be expected to work in the interests of each individual.