There is a strange presumption in recent thought about human values. When we think about basic issues in ethics and politics, it is taken as a given that we face a choice between liberalism and relativism. Believing that human values are cultural constructions that vary widely across time and space, relativists urge us to be conscious of difference. If they have a political message it is one of tolerance: “Don’t try to impose your way of life on others; be sensitive to the claims of cultural minorities in your own society.” Liberals, on the other hand, insist that there are requirements of justice or rights that apply to all human beings regardless of the communities or cultures to which they belong. The liberal political message is one of universalism: “The human species is–or may one day become–a single moral community in which the same values are honored everywhere.” Either we commit ourselves to liberal universalism or we must embrace moral relativism.

There are many things wrong with this dichotomy. One of the most obvious is that it is highly parochial. Liberalism may look like the only game in town these days, but just a generation ago there were Marxists, anarchists, socialists and others who believed a systematic alternative to liberal society was desirable, imaginable and practically feasible. Further back in the history of thought, there were many versions of universalism–most of them nonliberal. Plato, Aristotle, Augustine and Aquinas all believed in universal values, but no one would call them liberals. Looking outside the Western tradition, the same is true of Confucian, Buddhist and Islamic thinkers. It is one thing to assert the existence of universal values, quite another to claim these values are in some sense liberal. It is also true that most relativists have not been greatly concerned with issues of difference. Often relativism has gone hand in hand with the idea that society is an organic whole–a highly dubious notion, which if it tends to support diversity does so only at the level of entire cultures. Herder and the Romantics celebrated the differences among peoples, but they were indifferent or hostile to the claims of cultural minorities.

The idea that we must choose between liberalism and relativism reflects the poverty of the contemporary political imagination and a disabling loss of historical memory. Kwame Anthony Appiah’s Cosmopolitanism: Ethics in a World of Strangers is a welcome attempt to resurrect an older tradition of moral and political reflection and to show its relevance to our current condition. Appiah, a professor of philosophy at Princeton, seeks to revive cosmopolitanism, a view of humans as citizens of the world that was advanced by the Cynics in Greece in the fourth century BCE and elaborated by Stoic philosophers in Roman times. In Appiah’s view cosmopolitanism has two intertwined strands: the idea that we have obligations to other human beings above and beyond those to whom we are related by ties of family, kinship or formal citizenship; and an attitude that values others not just as specimens of universal humanity but as having lives whose meaning is bound up with particular practices and beliefs that are often different from our own. Appiah sees this cosmopolitan perspective re-emerging in the Enlightenment and expressed in the 1789 Declaration of the Rights of Man and Kant’s idea of a League of Nations.

As a position in ethical theory, cosmopolitanism is distinct from relativism and universalism. It affirms the possibility of mutual understanding between adherents to different moralities but without holding out the promise of any ultimate consensus. There are human universals that make species-wide communication possible–and yet these commonalities do not ground anything like a single universally valid morality or way of life. Clearly this is a position that carries within it a certain tension. The idea that we have universal moral obligations is not always easily reconciled with the practices and beliefs that give particular human lives their meaning. Appiah recognizes this tension, and writes: “There will be times when these two ideals–universal concern and respect for legitimate difference–clash. There’s a sense in which cosmopolitanism is the name not of the solution but of the challenge.”

A large part of Cosmopolitanism spells out the philosophy that underpins this position. What Appiah has to say in defense of cosmopolitanism is eminently sensible, but it is in no way new. In a move that will be familiar to anyone who recalls the ideas about “open texture” and “essential contestability” that were at the forefront of philosophical debate about language and values a generation ago, Appiah suggests that moral discourse is essentially practical in character. It seeks to express our desires and shape the attitudes of others rather than to report the way things are in the world. Like other types of discourse, moral language requires the use of judgment, which means different people will use it in different ways; but that does not mean morality is subjective. Rather, it means the possibility of moral conflict is built into language itself. As Appiah puts it: “When we describe past acts with words like ‘courageous’ and ‘cowardly,’ ‘cruel’ and ‘kind,’ we are shaping what people think and feel about what was done–and shaping our understanding of our moral language as well. Because that language is open-textured and essentially contestable, even people who share a moral vocabulary have plenty to fight about.”

Appiah argues that as a result of the influence of positivism, an erroneous view of moral language has come to be widely accepted. For positivists science is the model for all other modes of discourse, and since moral reasoning contains nothing like the procedures for verification and falsification that are found in science, ethics is bound to seem a second-rate form of thought. Quite correctly, Appiah maintains that a great deal of human discourse does not fit this positivist model. When people with divergent moral outlooks talk to one another about the good life, he suggests, they are usually not engaged in argument. They are best understood as partners in conversation–an open-ended encounter that can be useful and enlightening even if, as is commonly the case, it does not end in consensus. As Appiah elegantly puts it: “We enter every conversation–whether with neighbors or with strangers–without a promise of final agreement.” We can enter into the moral worlds of others and come to see that we partake in a common humanity without ever converging on a shared morality.

Appiah’s version of cosmopolitan ethics strikes me as being very close to the value-pluralism defended by Isaiah Berlin, and it suffers from some of the same weaknesses. The advantage of Berlin’s view is that it can acknowledge rationally insuperable moral differences without falling into relativism. Contemporary relativists follow the ancient Greek Sophists in holding that judgments of value are matters of opinion. However, human life contains goods and evils that do not depend on our opinions. To be at risk of genocide or subject to torture is an evil for all human beings whatever their beliefs. These evils are not culture-relative, and protection from them is a species-wide good. Once we recognize this, we cannot avoid speaking of universal human values; but this is not the same as having a universal morality. As Berlin never ceased to remind us, the most fundamental human values can make conflicting demands in practice, and in some of these conflicts reasonable people end up with different views of what is right. That is one reason there are different ways of life.

Value-pluralism undercuts the claims of all universal moralities, including liberal morality. Like Berlin in some of his writings, Appiah seems to want to celebrate moral diversity and at the same time endorse the universality of liberal values. The result is that he is constantly pulling liberal rabbits out of cosmopolitan hats. In discussing the issue of gay marriage, for example, Appiah informs us that while most Americans are against it they don’t quite know why, whereas for those who favor gay marriage it just seems right. He adds: “The younger they are, the more likely it is that they think gay marriage is fine. And if they don’t, it will probably be because they have had religious objections reinforced regularly throughout life in church, mosque or temple.” It’s not clear how Appiah knows this to be true, but that is not the point. What some people end up feeling cannot decide a question of this kind. If many religious people preach against gay marriage, it is because they believe being gay is wrong. If others think that “gay marriage is fine,” it is because they believe there is nothing wrong with being gay. The point is that one cannot avoid making a moral judgment, and this inescapably means accepting or rejecting certain religious beliefs. Those who favor gay marriage–as I do–do so because they reject the belief that being gay is in any way bad or wrong. Cosmopolitanism has very little bearing on the issue.

Appiah defends cosmopolitanism in the apparent belief that it tends to bolster liberal values, when in fact it is bound to be open-ended. Cosmopolitan thinkers may endorse some liberal positions, but this has nothing to do with the logic of cosmopolitan theory. As a political theory, cosmopolitanism is a doctrine of live and let live–a very different thing from liberalism as usually understood today. Appiah tells us that the cosmopolitan view was expressed in modern times in the Declaration of the Rights of Man, but actually it was most clearly held by thinkers who had no truck with declarations of rights. For Thomas Hobbes and David Hume the end of politics was not a regime of rights but peace–and they were ready to curb freedom whenever it posed a serious threat to the achievement of that end. Again, Michel de Montaigne is surely one of the great early modern exponents of cosmopolitan ethics. He affirmed a common humanity transcending differences of custom and tradition–and at the same time denied that any one way of life was best for everyone. These modern cosmopolitans were too aware of the intractability of human affairs to imagine that great human evils such as anarchy, war and tyranny could be overcome by seeking to make a single form of government universal. They believed–to my mind rightly–that pursuing such a goal would only add to the sum of human evils. Nothing could be more alien to these cosmopolitan thinkers than the missionary certainties of the kind of liberalism that seeks to establish one type of regime throughout the world.

Appiah believes that cosmopolitan theory has a special relevance today, and he succeeds in showing that this neglected and attractive tradition of thought deserves serious attention as a habitable middle ground between liberalism and relativism. Where he fails is in not exploring the points at which cosmopolitanism and liberalism diverge. Yet these are precisely the areas where a cosmopolitan viewpoint is currently most needed. As Appiah notes, contemporary thought is beset by the notion that we can live together only if we are alike. In international relations this idea is expressed in the prevailing belief that only regimes that respect human rights or practice democracy (it’s not always clear which) can be legitimate–a view that has been used by the neoconservative right to justify the calamitous attack on Iraq. If we are to avoid similar disasters in the future, we need an account of legitimacy as applied in the society of states that is not just a recent version of liberalism writ large. Cosmopolitanism could surely help frame such an account, but it would have to be more willing to challenge current pieties than the version presented by Appiah.