Prisoner's Dilemma and Social Justice: A Reply

Abstract

In a recent notel prompted by a paper of ours published in Mind in I965, John Smyth first quotes, but does not dispute, our claim a useful sense may be given to Rousseau's concept of the 'general will' by reference to the theory of non-zero-sum non-cooperative games, and then goes on to dispute our argument 'a contract falling within a set of rules conforming to an unambiguous general also falls within a set of rules that satisfy the (Rawlsian) criterion of social '. He argues 'the problem of obtaining the object of the general will is essentially a problem not of obtaining a Rawlsian rule or contract, but a problem of enforcing a rule or a contract' (p. 427). It seems to us Smyth's objection is based on a confusion between two different problems: (i) How can the 'general will', as we interpret it, be enforced? (2) Will an 'unambiguous general will' pass Rawls's test of 'social justice'? Smyth is interested in (i), and is accordingly led to the difficulties of devising enforceable sanctions in the case of the Prisoner's Dilemma. He seems, however, to be under the impression this somehow undermines our affirmative answer to question (2). This is clearly a mistake, since Smyth himself agrees subsequently 'a just contract is not necessarily an enforceable contract' (p. 430). It would, if our argument required it, be perfectly possible to envisage the parties to Prisoner's Dilemma being subject to an automatic penalty device of the form of a Doomsday Machine. But even if it were not, it still would not follow their contract embodying the 'general will' would fail to meet Rawls's criterion of social justice. The relation of a contractual theory of fairness and justice in the manner of Rawls to the notion of the general will rests precisely on the supposition parties to the contract would recognise it to be to their interest to make some sort of firm commitment in advance. Mr. Smyth says nothing which invalidates our claim men in Rawls's 'original position ' 2 would agree, among other things, not to confess if they were in due course to find themselves in a 'Prisoner's Dilemma' situation, and should therefore accept if they were to confess they would be behaving unjustly. Enforcement is a separate issue altogether.