In the late 1980s, I was told about a boy in Brooklyn who, on his way to school, found a wallet full of money. Despite the fact that it was also full of identification, he could find no teacher or administrator willing to tell him what to do with it. Should he keep the money? Maybe, since he lived in near poverty. Should he return it? Maybe, since it really wasn't his. But nobody would help him decide. To do so, the adults feared, would merely be to impose their values on him.
That kind of ethical relativism - the assumption that education must be morally neutral, and that all values are situational and negotiable - is mercifully fading out. Cosmopolitanism: Ethics in a World of Strangers by Princeton University philosopher Kwame Anthony Appiah pushes it further toward obsolescence. Values, Appiah argues here, are not convenient illusions but objective essentials of the human condition. Deftly, and with wide scholarship lightly applied, this small but alluring book demolishes a key tenet of relativism, which Appiah describes as "the basic suspicion that moral claims just reflect local preferences" rather than universal truths.
Like most demolitions, however, this one leaves a gaping hole in the philosophical ground. Before relativism's destruction, its proponents relied on the comfortable certainty that tolerance trumped all other values. For relativists, dealing with multiple cultures was easy: Just tolerate everything. But absent that idea, how do we relate to what Appiah calls "a world of strangers"? Since there are "some values that are, and should be, universal," do we deliberately rinse away all expressions of cultural diversity that don't uphold those universals?
In 2006, these are not idle questions. Long before Tom Friedman popularized the idea of a flat world, cultural differences were beginning to fuse into a global mélange of commercial and political sameness. But if values are universal, how can we maintain them while still respecting cultural distinctness? How can we avoid the pitfall those Brooklyn relativists feared - that of imposing our values on others?
Like an owner's manual for a flat world, "Cosmopolitanism" helps us find ways to consider such conceptual complexities. It does so by encouraging us to become citizens of the world. The author's principal example of such a citizen is, oddly enough, himself. While that might sound like a recipe for egotism, Appiah makes it work.
The child of an English mother and a Ghanaian father, he was raised in the Asante region of Ghana among a polyglot array of Christians and Muslims who happily mixed African witchcraft with modern commerce. Schooled in English but speaking Asante-Twi, educated at Cambridge University, and teaching in America, he has plenty of reason to want to be cosmopolitan rather than local.
But what does he mean by this term? Tracing it back to 1788, he defines it through two intertwined meanings. One is the idea that "we have obligations to others" that "stretch beyond those to whom we are related" and even go beyond "the more formal ties of a shared citizenship." The other is that "we take seriously the value not just of human life but of particular human lives, which means taking an interest in the practices and values that lend them significance."
For the cosmopolitan, then, "no local loyalty can ever justify forgetting that each human being has responsibilities to every other." Those responsibilities are best played out in "conversations across differences" where the "language of values ... helps us coordinate our lives with one another."
Perhaps Appiah's most salient contribution, however, is his definition of counter-cosmopolitanism. The problem for relativists is that, since values are never bad but just different, there's no basis for condemning either radical Islamists blowing up tall buildings or Christian fundamentalists bombing abortion clinics. Appiah has no such problem. For him, the recognition that there are right values can, in the hands of Muslim or Christian fundamentalists, merge dangerously into the idea that "my" values are the only right ones. Out of that misplaced philosophy, he says, arises "cruelty conducted ... in the name of moral cleansing, murder in the name of universal truth."
The challenge for the cosmopolitan, then, is "how, in principle, to distinguish benign and malign forms of universalism?" I'm not certain the book provides a clear answer. I say it that way because this book's strength is not in its coherence. To state Appiah's definitions as I've done above, for example, makes them seem more orderly than they are. In fact, the quotations above are drawn from various pages, sometimes widely separated. Given that the book reads more like a pleasant conversation than a logical tract, that's not a serious fault. In conversation, where thoughts are less linear than organic, nobody expects all similar ideas to be gathered into one place.
That doesn't make this "philosophy lite," but it does mean that its ideal reader is not another philosopher but rather a literate nonspecialist reader. By elevating the public discussion of globalization to such a professionally philosophical level, Appiah provides an intriguing basis for the internationalist mind-set.
But by surrendering to others the task of organizing these ideas into a framework for creating a cosmopolitan culture, Appiah may come under fire from those who see this book as the work of a dilettante. If he does, cosmopolitans will recall that dilettante comes from the Italian verb "to delight," and means a true lover of the arts, not simply an amateurish dabbler. But then, that proves one of Appiah's points, which is that 21st-century ideas need to be understood in a global, rather than a local, context.
• Rushworth M. Kidder is president of the Institute for Global Ethics in Camden, Me., and author of "Moral Courage."