In the last forty years, political philosophy has witnessed a plethora of visions of the just society—natural rights libertarianism, ”left” libertarianism, prioritarianism, sufficientarianism, egalitarianisms of a stunning variety, republicanism; theories of economic desert, welfare, need, and capabilities. And, of course, the old standby, utilitarianism. (We must not forget that many a hard-headed economist, insisting that he will have no truck with philosophical talk, proceeds to announce his allegiance to some form of social utility as the standard of justice.) Political philosophers self-identify with their sects (“I’m an egalitarian.” “Not me, I’m a libertarian.” “Well, I’m a sufficientarian welfarist with prioritarian leanings!”) Each of the dizzying variety of philosophical sects presents itself as possessing the truth about the just political organization and tells its adherents that the other sects either are recommending injustice, are not truly liberal, or have committed a heresy in, say, advocating resource egalitarianism over welfare egalitarianism, or left-libertarianism over orthodox rights libertarianism.
This understanding of political philosophy—as the theorist’s vision of the perfectly just society based upon her “intuitions” or controversial “theory” of justice—is facing a crisis of credibility. Perhaps the original hope was that the systematic use of human reason would lead enquirers and citizens to converge on the truth about “distributive justice” or “the role of the state,” but any impartial observer must conclude what should have been obvious all along: as in so many matters, the free use of human reason leads to sustained disagreement and a proliferation of sects. This is not a mere episode on the way to consensus and enlightenment, but “a permanent feature of the public culture of democracy.” Such was the deep insight of the greatest political philosopher of the twentieth century, John Rawls. Because the use of our reason on these matters is inherently controversial, political philosophy must, as he tells us, apply the principle of toleration to philosophy itself. Liberalism’s founding insight was the recognition in the sixteenth and seventeenth centuries that controversial religious truths could not be the basis of coercive laws and public policies. The task is now to apply this insight to philosophizing about justice itself. This is an extraordinarily difficult lesson for many. Can it really be that I should not endeavor to ensure that my society conforms to my “knowledge” of justice? (Compare: can it really be that my “knowledge” of God’s will should not structure the social order?)
Public reason liberalism seeks to respond to this crisis in the credibility of political philosophy by grounding public rules and institutions in the reason of all. Political institutions, social structures, and basic social rules are politically or morally justified only if they can be endorsed from the perspective of each and every free and equal “reasonable and rational” person. Public reason liberalism sets aside the illiberal dream of founding social and political order on a shared truth about the nature of justice, replacing it with the aspiration of finding terms of association on which good-willed and reasonable citizens, disagreeing about basic aspects of the good life and the ideally just society, can converge. This conception of liberalism is literally revolutionary—it seeks to return liberalism to its founding insight that we must live together without sharing our deepest visions: that liberalism is an alternative to sectarianism, not simply a form of it.
The regulative aim of public reason liberalism is to inquire whether—and if so, how—free and equal persons with deep and enduring disagreements might all come to endorse a social and political order. The obvious liberal solution would appear to follow John Locke. Political philosophy must distinguish civil interests, which we all share, from religious disputes, which set us at odds. “I esteem it above all things,” says Locke, “necessary to distinguish exactly the business of civil government from that of religion, and to settle the just bounds that lie between the one and the other. If this be not done, there can be no end put to the controversies that will be always arising between those that have, or at least pretend to have, on the one side, a concernment for the interest of men’s souls, and, on the other side, a care of the commonwealth.” A successful liberal state must focus on what we share, and it must privatize those matters about which we disagree. This essentially Lockean view has been pressed by Rawls and his followers, according to whom liberalism’s public reason is based on the reasons that we share. So understood, the aim of public reason liberalism is to identify a set of reasons that we all have in common as citizens, and to constrain the political to it. Having done that, we can then discover political consensus insulated from our wider valuational and religious diversity.
The advice of this orthodox understanding of public reason is to set aside that which divides us, and focus our common political life on that which unites us. It is advice that has proven impossible to follow. The resurgence in the last thirty years of religiosity and religion-based politics undermined the hope that our deep divisions about the good life and our place in the universe could be confined to the private sphere. As in Hobbes’s time, religious conviction again leads to political dispute. In response, proponents of the orthodox view flounder, either simply insisting that religious citizens have a moral duty to refrain from appeal to their faith in the public arena, or offering strained “provisos” that allow religion in—as long as, in the end, it can be backed up with the secular reasons that truly matter.
Within the academy, the counsel of focusing on our shared secular reasoning has led not to consensus and an end to “controversies,” but to a radicalization and fracturing of political philosophy into the various all-too-familiar sects. While in A Theory of Justice Rawls was confident that it was within the human horizon for all to agree on “the same principles of justice,” his later works evince increasing skepticism that this can be achieved. Even when we restrict our deliberations to a common set of political values, Rawls concluded, we will end up disagreeing on what are the best or most reasonable principles. Rather than holding that all reasonable persons can be brought to endorse the very same principles of social justice, his final aspiration was that reasonable citizens will share a general liberal view of justice. “By this I mean three things: first, it specifies certain basic rights, liberties, and opportunities (of the kind familiar from constitutional democratic regimes); second, it assigns a special priority to these rights, liberties and opportunities, especially with respect to claims of the general good and of perfectionist values; and third, it affirms measures assuring all citizens adequate all-purpose means to make effective use of their basic liberties and opportunities.” Because, Rawls says, “each of these elements can be seen in different ways, so there are many liberalisms.”
A nonsectarian liberalism is deeply skeptical that reasonable and rational people will ever concur on principles of distributive justice, the extent of property, or the role of the state. The most at which we can realistically aim is convergence on a set of principles or policies that all reasonably reflective and good-willed citizens can endorse as in some sense acceptable. Good-willed, reasonable, and rational people will always disagree on what is the best principle of justice, the best constitution, or the best practice of property. Only the self-assured, self-righteous sectarian now can doubt that, or charge that her opponents have made some error perceptible to normal human reasoning. (Of course she claims that they have made an error perceptible to her reasoning—but that is the quintessential sectarian claim). In our pluralistic world the only consensus within our reach is on the contours of an eligible set of principles, practices, or constitutions. Interestingly, even in A Theory of Justice Rawls recognized this in regard to matters of justice below his grand two principles. Often, he pointed out, our test for whether policies or institutions are just will be indeterminate. “But when this is so, justice is to that extent likewise indeterminate. Institutions within the permitted range are equally just….” This, I have argued, is the general case: the best we can do is to identify a set of possible arrangements, each of which reasonable individuals have sufficient reason to live by, but which they rank very differently. The fundamental critical question concerns the test: how do we identify the range of justice?
The beginning of an answer is to realize that to endorse rules and practices as just is to adopt a set of attitudes towards them. To see a rule as specifying a requirement of justice is to experience resentment and indignation at its violation by others, and guilt and remorse when one violates it. It is to accept that the behavior covered by the rule is properly the business of others, and that punishment and censure will typically be appropriate responses to violations. These attitudes and sentiments are endogenous to the practice of justice: they are core aspects of what we mean when we say that something is a matter of justice.
An adequate public reason liberalism will inquire, for any actual or proposed rule of justice, whether good-willed and rational agents, reflecting on their entire set of concerns, have sufficient reason to adopt these attitudes, and welcome these concommitments of a rule of justice. If they do—if given one’s set of evaluative considerations, which sometimes overlap with those of others and sometimes are distinctive—then in one’s view the rule has passed the test: it is a rule that one has reason to treat as is befitting a rule of justice. There is no reason to think that a person only has reason to adopt these sentiments and attitudes towards the rule she thinks best. As rules of social and political morality, the rules of justice are generally a great good, ordering our social life so as to provide the framework for cooperation and mutual benefit. In reflecting on their public acceptability we are not concerned with bargaining, bluffing, or disputes in the pages of a philosophy journal. The question on which we should focus is whether, given the costs and benefits to our evaluative standards, the benefits of adopting these attitudes towards some rule are greater than the costs for all. Simplifying—but not so much as to obscure the critical point—if they are, a person has reason to embrace this rule as within the range of justice.
Of course different people will apply this test with different results. Some will identify a wide range of justice, while for others it will be narrower. But the liberal insight is that in a social world of great diversity the only possible sets on which we can converge are ones with extensive individual freedom—what Benjamin Constant called the “liberties of the moderns,” the “right of everyone to express their opinion, choose a profession and practice it, to dispose of property, and even to abuse it; to come and go without permission, and without having to account for their motives or undertakings. It is everyone’s right to associate with other individuals, whether to discuss their interests, or to profess the religion which they and their associates prefer, or even simply to occupy their days or hours in a way which is most compatible with their inclinations or whims. Finally, it is everyone’s right to exercise some influence on the administration of government, either by electing all or particular officials, or through representations, petitions, demands to which authorities are more or less required to pay heed.”
Beyond this, we have reasonable disputes about what type of property arrangements we shall have, what will be supplied privately and what publicly, the scope of the sphere of privacy, and so on. On all these matters the eligible set will have numerous elements. A distinctive feature of classical liberals is that, as a rule, they tend towards more restricted sets. As John Stuart Mill argues in the fifth book of The Principles of Political Economy, state-enforced justice is backed by coercive force, and coercion is always a dangerous tool. Perhaps more than any other matter, classical liberals have made us aware of the dangers of coercive regulation, and so have insisted that benefits of legislation be manifest and significant. And so the classical liberal is apt to be among the more skeptical that the benefits of coercive regulation are truly worth the costs.
We must, though, be careful. The basic rules of justice are great goods to all, and so the determination that one could not adopt the requisite attitudes towards a rule is a grave conclusion, not to be easily reached. Certainly, the classical liberal’s acceptable range must be based on recognition that there are many acceptable property practices, and that most (perhaps all) of these will include transfer payments. Classical liberals are rightly impressed by market processes, and as citizens they appropriately urge employing them on a wide variety of fronts. But they must also recognize that these are typically controversial claims, based both on a certain weighing of a specific set of values and uncertain empirical evidence. As are other citizens; of course they are convinced that they are correct, but a conflict of confident political judgments is the stuff of a diverse society.
Because the best public reason liberalism can hope for is an eligible set (of constitutions, principles of distributive justice, property practices, etc.) with more than one element (the set is non-empty because disagreement is not without limit, it has more than one member because disagreement about political morality is ubiquitous), all plausible public reason liberalisms must devise some way to select from the socially eligible set. There is a range of justice, but to regulate our shared social life there must be some common understanding of justice. Public reason tells us that, from the public point of view, there is no best choice but that any member of the eligible set is better than any option outside the set. A Lockean will hold that we should appoint a constitutional umpire, who is constrained to provide determinations within the socially eligible set. And certainly a large number of our disputes must be handled through democratic adjudication. Recently I have argued that the Lockean solution is often complemented by a social process that yields a moral equilibrium on one member of the set. However, for present purposes the important point is not specifically how a liberal theory of public reason selects from the eligible set, but that it must have some account of how to do so. Some account of how we sort through bounded disagreement and select from the eligible set is necessary for any plausible liberal theory.
Should we come to coordinate on some member of the eligible set, we can achieve a free justificatory equilibrium. For each person in a diverse society, considering those values and commitments that are central to her understanding of the good and the just, acting justly will be the best reply to the just actions of others. Because each draws on her wide set of normative commitments in endorsing a rule of justice, and so moral justification does not demand that she brackets that about which she most cares, the temptations to defect on justice are minimized. The more political justification sets aside a citizen’s deep concerns, the more she is apt to see justice as a severe cost—justice could demand that she regularly set aside that which she considers most dear. As Rawls recognized, if a just society is to be stable, the rules of justice must be in a sort of Nash equilibrium: given the just action of others, one’s overall best response is to reply in kind.
Yet, while such a society can be a free moral equilibrium, the temptation of sect-based defection remains. To acknowledge that the principles that regulate our social and political order will never be the ones that everyone endorses as best requires a moral maturity on the part of both the political philosopher and citizen. The first impulse of the political philosopher is to optimize—to demand the best, the ideal, the perfect according to his own reflections. To be sure if (and only if) his sectual preference is within the eligible set, he may press for it in the public forum on disputed issues. But he must abjure all claim that his is the uniquely just view, the others being merely impostors or, worse, disguised evils. (I was once on a public panel at a major research university on the topic of affirmative action, advancing what I took to be the modest thesis that there are reasonable worries about it, and those who oppose it are not evil. My co-panelists and the audience roundly rejected this outrageous suggestion.) The morally mature citizen and philosopher knows that a diverse society will never come to share a conception of the best, and that means that she must reconcile herself to living under principles and practices that she does not think are the best, or in fact anything very close to it. Only this mature attitude allows widespread reconciliation to a social world of diversity, which includes diversity of political views. Those with such a mature attitude will not be alienated from their social and political world as are so many of today’s political philosophers and citizens; they will not chafe at being subject to principles and practices that they deem fall far short of the best as they have come to understand it.
Of course one with a mature attitude that allows reconciliation to a social and political world of diversity need not reconcile oneself to every possible principle or practice. The mature attitude need not abandon the critical stance: it must place some limits on what can be endorsed. In short, while abandoning the optimizing stance it must not endorse repression and injustice. The mature attitude sees the distance between falling short of the best and oppression — a difference the sectarian cannot see. The sectarian political philosopher (at least in her writings though not in her actual social life) is apt to deem as unjust all those regimes that do not conform to her favored “theory of justice.” The difference, though, between less-than-the-best and the unacceptable is real. There is a wide range of the just. In a world of diversity, a just and free society can only be achieved once citizens and philosophers appreciate the distance between what is acceptable and their sect’s vision of the best.
Gerald Gaus is the James E. Rogers Professor of Philosophy at the University of Arizona, where he directs the program in Philosophy, Politics, Economics & Law. His most recent book is The Order of Public Reason: A Theory of Freedom and Morality in a Diverse and Bounded World (Cambridge University Press, 2011). His website is www.gaus.biz.
 John Rawls, Political Liberalism, paperback edn. (New York: Columbia University Press, 1996), p. 36.
 John Locke, “A Letter Concerning Toleration,” in the Works of John Locke in Nine Volumes, 12th edn. (London: Rivington, 1824), vol. 5, pp. 9-10
 John Rawls, Political Liberalism, p. 223.
 John Rawls, A Theory of Justice, revised edition (Cambridge, MA: Harvard University Press, 1999), p. 176.
 Benjamin Constant, “The Liberty of the Ancients Compared with that of the Moderns” in Political Writings of Benjamin Constant, edited by Biancamaria Fontana (Cambridge: Cambridge University Press, 1988), pp. 308–28.
 Roughly, we can say that public reason give us a maximal set but not an optimal choice. On the rationality of choosing from such sets, see Amartya Sen, “Maximization and the Act of Choice,” in his Rationality and Freedom (Cambridge, MA: Harvard University Press, 2002): 159-205.
 See my Order of Public Reason (Cambridge: Cambridge University Press, 2011), especially chap. VII.
 This has been brought out in Paul Weithman’s masterful study, Why Political Liberalism? (Oxford: Oxford University Press, 2010).