"In the final message my father left for me and my sisters, he wrote, 'Remember you are citizens of the world.' But as a leader of the independence movement in what was then the Gold Coast, he never saw a conflict between local partialities and a universal morality — between being part of the place you were and a part of a broader human community. Raised with this father and an English mother, who was both deeply connected to our family in England and fully rooted in Ghana, where she has now lived for half a century, I always had a sense of family and tribe that was multiple and overlapping: nothing could have seemed more commonplace.

"Surely nothing is more commonplace. In geological terms, it has been a blink of an eye since human beings first left Africa, and there are few spots where we have not found habitation. The urge to migrate is no less 'natural' than the urge to settle. At the same time, most of those who have learned the languages and customs of other places haven't done so out of mere curiosity. A few were looking for food for thought; most were looking for food. Thoroughgoing ignorance about the ways of others is largely a privilege of the powerful. The well-traveled polyglot is as likely to be among the worst off as among the best off — as likely to be found in a shantytown as the Sorbonne. So cosmopolitanism shouldn't be seen as some exalted attainment: it begins with the simple idea that in the human community, as in national communities, we need to develop habits of coexistence: conversation in its older meaning, of living together, association.

"And conversation in its modern sense, too. The town of Kumasi, where I grew up, is the capital of Ghana's Asante region, and, when I was a child, its main commercial thoroughfare was called Kingsway Street. In the 1950s, if you wandered down it toward the railway yards at the center of town, you'd first pass by Baboo's Bazaar, which sold imported foods and was run by the eponymous Mr. Baboo — a charming and courteous Indian — with the help of his growing family. Mr. Baboo was active in the Rotary and could always be counted on to make a contribution to the various charitable projects that are among the diversions of Kumasi's middle class, but the truth is that I remember Mr. Baboo mostly because he always had a good stock of candies and because he was always smiling. I can't reconstruct the tour down the rest of the street, for not every store had bonbons to anchor my memories. Still, I remember that we got rice from Irani Brothers; and that we often stopped in on various Lebanese and Syrian families, Muslim and Maronite, and even a philosophical Druze, named Mr. Hanni, who sold imported cloth and who was always ready, as I grew older, for a conversation about the troubles of his native Lebanon. There were other 'strangers' among us, too: in the military barracks in the middle of town, you could find many northerners among the 'other ranks,' privates and NCOs, their faces etched in distinctive patterns of ethnic scarification. And then there was the occasional European — the Greek architect, the Hungarian artist, the Irish doctor, the Scots engineer, some English barristers and judges, and a wildly international assortment of professors at the university, many of whom, unlike the colonial officials, remained after independence. I never thought to wonder, as a child, why these people traveled so far to live and work in my hometown; still, I was glad they did. Conversations across boundaries can be fraught, all the more so as the world grows smaller and the stakes grow larger. It's therefore worth remembering that they can also be a pleasure. What academics sometimes dub 'cultural otherness' should prompt neither piety nor consternation.

"Cosmopolitanism is an adventure and an ideal: but you can't have any respect for human diversity and expect everyone to become cosmopolitan. The obligations of those who wish to exercise their legitimate freedom to associate with their own kind — to keep the rest of the world away as the Amish do in the United States — are only the same as the basic obligations we all have: to do for others what morality requires. Still, a world in which communities are neatly hived off from one another seems no longer a serious option, if it ever was. And the way of segregation and seclusion has always been anomalous in our perpetually voyaging species. Cosmopolitanism isn't hard work; repudiating it is."