Alfred North Whitehead had a point when he suggested that European philosophy consisted of “a series of footnotes to Plato.” But this does not mean that Plato got everything right. Far from it. One does not footnote a text written by another simply to express agreement. Rather, such footnotes elaborate upon the original text, or express doubts about it, or expose ambiguities, or even correct clear and unmistakable errors. And this has happened to Plato's philosophy—mercilessly, unrelentingly, for more than two millennia, until little remains that has not undergone thorough revision. Those revisions have taken philosophy far, but they would never have been possible without Plato. And so no serious conversation on the subject can take place without some knowledge of his work. Plato did not solve all the great problems in philosophy—or any of them—but anyone who hopes to do so had better get right with him.

G.A. Cohen has exactly the same attitude regarding John Rawls. In his new book, Cohen names Rawls's A Theory of Justice (1971) as one of the three greatest works of Western political philosophy, along with Thomas Hobbes's Leviathan and (of course) Plato's Republic (p. 11). Cohen has been footnoting Rawls for many years now, in a series of critical books and articles that have culminated in the current work. As a result, Rescuing Justice and Equality is perhaps the most comprehensive critique of Rawls offered to date. The overall effect is that of a controlled demolition of Rawls's entire project. And yet such a work could have been written only by someone who thought that A Theory of Justice was a work of supreme importance to its field. Rawls may be wrong, and Cohen means to show it, but it is clear that to him, anyone who wants to say anything meaningful about justice had better get right with Rawls.

As the title of his book suggests, Cohen wishes to rescue both equality and justice from Rawls, who, he believes, is far too wiling to embrace economic inequalities as just. His rescue of equality occupies the first half of the book. Here, Cohen argues that a just society would not require economic incentives in order to ensure efficiency. In such a society, virtually every citizen would accept and embrace the principles of justice governing that society (principles which, both Rawls and Cohen agree, would be at least somewhat egalitarian). It would be contradictory for a citizen to declare allegiance to egalitarian principles and then refuse to work hard unless he or she received above-average pay. Here, Cohen takes aim at Rawls's efforts to separate the principles appropriate for governing a society's basic structure from the principles appropriate for regulating individual conduct. Cohen's point is not new, as he acknowledges; both Marx's essay “On the Jewish Question” (p. 1) and the feminist slogan “the personal is political” (p. 116) articulate similar points. Cohen's contribution here is to exclude certain types of motivation from being taken into account by principles of justice at a ground level. Egalitarian principles of justice might well have to be compromised because incentive effects are necessary for efficiency; but to the extent that this is true, Cohen concludes, the reason is that the society does not fully embrace those egalitarian principles. It is, therefore, important to distinguish between principles of justice and the difficulties raised by their practical implementation.

It is equally important, Cohen continues, to distinguish between principles of justice and other principles, such as efficiency. Efficiency and justice may both be good things, but they are not the same thing, and sometimes it might prove necessary to trade one off against the other. Cohen focuses on this point in the second half of his book. Here, he seeks to rescue justice from other things with which it might easily be confused. Rawls contributes to this confusion, Cohen argues, through the constructivism he regards as the correct way to identify principles of justice. The constructivist identifies justice with the overall principles of social regulation that would be chosen under the appropriate set of circumstances (i.e., Rawls's original position). But this method systematically runs together justice with all the other desirable features a society might have. It also runs afoul of certain basic intuitions about justice. Suppose, for example, that a new economic system was devised that made it possible to maintain the efficiency benefits of free-market capitalism but with much less inequality. Most egalitarians would surely say that the resulting new society was more just than the old. But if both societies were the best that could have been achieved under their respective circumstances, Rawls's constructivism would have to pronounce both societies equally just (p. 312).

If Cohen is right, then justice may be, as Rawls famously wrote, the first virtue of social institutions. But it is not their only virtue; arguably it is the first virtue among equals, but this privileged status does not grant it priority over all others, as Rawls suggests (Cohen's second point). Justice also is not only the virtue of social institutions; it is also an important virtue of individual behavior, and for precisely the same reasons (Cohen's first point). Both of these points, Cohen believes, tighten the relationship between justice and equality. Elsewhere, Cohen has defended a strongly egalitarian conception of justice, according to which all arbitrary differences between individuals (such as genetically based differences in talent) become irrelevant to the proper distribution of goods (a position known as luck egalitarianism). This conception permits few economic inequalities, except for limited ones based upon effort and sacrifice (plus potentially a few other factors, such as need). This position comes across as implausible, he argues, because high levels of equality seem unrealistic. But this complaint either mixes the principles of justice with other principles (usually efficiency) or subsumes under them various concessions that justice must make to a very imperfect human nature (again, usually in the name of efficiency). Once this fact is recognized, it becomes possible for justice to stand alone and make its demands uncompromisingly, even if those demands are never fully realized. It will then become much easier to imagine justice's demands to be strongly egalitarian ones.

If someone were to say that all political philosophy since 1971 has simply consisted of a series of footnotes to Rawls, I doubt that Cohen would object. But this fact does not minimize Cohen's accomplishment. It is no doubt true that progress in the study of justice requires that respect be paid to A Theory of Justice. But now, respect must be paid to Rescuing Justice and Equality as well.