We might become trustworthy. Each might then promise to do A on condition that the others make the same promise. We might become reluctant to be ‘free-riders’. If each believes that many others will do A, he may then prefer to do his share. We might become Kantians. Each would then do only what he could rationally will everyone to do. None could rationally will that all do E. Each would therefore do A. We might become more altruistic. Given sufficient altruism, each would do
