 Resolution of this debate between Gintis and Binmore fortunately need not wait upon discoveries about the deep human evolutionary past that we may never have. The models make rival empirical predictions of some testable phenomena. If Gintis is right then there are limits, imposed by the discontinuity in hominin evolution, on the extent to which people can learn to be self-regarding. This is the main significance of the controversy discussed above over Henrich et al.’s interpretation of their field data. Binmore’s model of social equilibrium selection also depends, unlike Gintis’s, on widespread dispositions among people to inflict second-order punishment on members of society who fail to sanction violators of social norms.  Gintis (2005)  shows using a game theory model that this is implausible if punishment costs are significant. However,  Ross (2008a)  argues that the widespread assumption in the literature that punishment of norm-violation must be costly results from failure to adequately distinguish between models of the original evolution of sociality, on the one hand, and models of the maintenance and development of norms and institutions once an initial set of them has stabilized. Finally, Ross also points out that Binmore’s objectives are as much normative as descriptive: he aims to show egalitarians how to diagnose the errors in conservative rationalisations of the status quo without calling for revolutions that put equilibrium path stability (and, therefore, social welfare) at risk. It is a sound principle in constructing reform proposals that they should be ‘knave-proof’ (as Hume put it), that is, should be compatible with less altruism than might prevail in people. Thus, despite the fact that the majority of researchers working on game-theoretic foundations of social organization presently appear to side with Gintis and the other members of the Henrich et al. team, Binmore’s alternative model has some strong considerations in its favor. Here, then, is another issue along the frontier of game theory application awaiting resolution in the years to come.