In this rapidly changing world, concepts of human identity can be a seismically divisive force. Across some of the most hostile divides-religious wars, ethnic clashes-those on either sides too often identify themselves exclusively with a particular group.They believe that they hold dear values that the "other" does not. And, at the great peril of the world community, many still continue to struggle to prove that their views are unequivocally right.

But a shared human identity can also be a powerful unifier. On 5 June 2006, renowned scholars Kwame Anthony Appiah and Amartya Sen were invited to explore the topic of "Identity in the 21st Century" in the latest Secretary-General's Lecture Series. Following in the tradition of the Series that has hosted such premier intellectual figures as Archbishop Desmond Tutu and Toni Morrison, Mr. Sen and Mr. Appiah discussed their visions of human identity and their hopes for tolerance in the next century. The lecture hall resounded with the joint theme of their prominent recent work: as easily as human identity can drive people apart, it can help them navigate their differences through an abruptly shrinking world.

From left to right: Edward Mortimer, Amartya Sen, Kofi Annan and Kwame Anthony Appiah, during the Secretary-General's Lecture Series on "Identity in the 21st Century" UN Photo

Mr. Sen, a Nobel Laureate in economics, whose many works include his most recent book, Identity and Violence: The Illusion of Destiny, described the endless corridors through which a single human identity wanders. At the same moment, one can be a United States citizen of "Asian background, of Indo-Chinese origins, with Vietnamese ancestry. A Christian. A liberal. A woman. A vegetarian … A theatre-lover. An environmental activist. A jazz musician …" and so on, he said, with endless links to others all over the globe. Each categorization aligns a person with some fellow humans and creates distance from others. But taken as a whole, he stressed that a multifaceted understanding of one's own identity can bridge the gaps that divide us and create networks of understanding. Conversely, a singular overarching system of categorization can pit individuals against each other.

Besides overstating the importance of a single identity factor, such as religion or national allegiance, humans have a tendency to exaggerate the homogeneity of a group, said Mr. Appiah. A philosopher and professor at Princeton University, he has written extensively on the meaning of culture. He pointed out that it is naïve and wrong-headed to think that all Muslims, for example, are exactly the same, when in fact they span many countries, cultures and ethnicities. "In a time of intense social crisis, people fall back on these labels", Mr. Appiah said. Today's world is full of abrupt changes that have made people turn inward, toward others they see as fundamentally compatible with themselves, but a more peaceful, progressive path would explore dialogues with others. Learning from those different from us, he continued, can lend insight into the aspects of humanity that transcend categorization.

This is the basis of the theory of "cosmopolitanism", an age-old word literally meaning the condition of world citizenship. Mr. Appiah's provocative book, Cosmopolitanism: Ethics in a World of Strangers, renews that meaning. He points out that the idea of a tolerant world has survived Alexander's bulldozing of cultures far and wide and Rome's unilateral worldview. Several ancient Greeks, in fact, called themselves "citizens of the world" and rejected such narrowly nationalistic, tyrannical rule. Early Christians stressed the unity of all peoples, as did German philosophers like Emmanuel Kant, whose cosmopolitan essay "To Eternal Peace" (1795) was the basis for the treaty of the League of Nations and ultimately for the United Nations, he said.

Cosmopolitanism is especially useful today, Mr. Appiah noted, because it is essentially contrary to the idea of tyranny and cultural conversion-goals inherent on both sides of what many call today's "clash of civilizations". A cosmopolitan world is one based on an underlying humility and on the fallibility of human knowledge. In believing that all people have many things to learn, the door to true tolerance is swung open. "Cosmopolitans think that there are many values worth living by and that you cannot live by all of them", he writes in his book. "So we hope and expect that different people and different societies will embody different values."

Mr. Appiah also pointed out that "globalization has made these ancient ideas relevant". Cosmopolitanism requires both knowledge of other peoples and the power to affect and be affected by them. People are likely already cosmopolitan in many ways-the roots of music and art, for example, reach deep into international soil, connecting such diverse places as West Africa and the American South, London and Bangladesh, he said. Moreover, global media and powerful international systems have made direct international relationships a sudden reality. Our choices as a human race must reflect the heavy responsibility of this shift.

Both Mr. Sen and Mr. Appiah agreed that ample opportunities for mutual understanding exist in people's personal interactions. This can be seen in the modern preoccupation with cultural diversity-a concern often misinterpreted in terms of quotas and political correctness. The bottom line of intercultural dialogue, Mr. Appiah said, is a cosmopolitan concern for one's fellow man. "At the heart of modern cosmopolitanism is a respect for diversity of cultures, not because cultures matter themselves but because people matter, and culture matters to people."

Mr. Sen said that dialogue across different identity groups has proven to be a powerful tool in recent history, but he criticized the fundamental principle behind a "dialogue among civilizations". Dialogue is always among individuals, he said, reiterating that narrowly defined cultural identities have been problematic in the past. He warned that any rigid categorization could be dangerous. Identification along class lines brought people together during the early labour movements, he explained, but it often neglected to see labourers as the fathers, husbands and individual citizens that they also were. An overly stringent attachment to the notion of ethnic identity led to genocide in Nazi-run Germany, as well as in Rwanda and the Balkan States of recent years.

The evocative Identity and Violence also zooms in on Mr. Sen's cultural pet peeve: the hijacking of the concepts of tolerance and democracy by Western culture. In aligning themselves with these notions, which Mr. Sen writes are prevalent in Asian history, Westerners necessarily condemn others as inherently intolerant or tyrannical. Such misconceptions are yet another way in which drawing lines between groups can turn individuals against each other and exacerbate the problems that politics and war have begun. Beyond the hazards of dogmatic understandings of identity, there is an even more universal reason to think of people as complicated, multifaceted creatures, according to Mr. Sen. Human life cannot be described by religion, ethnicity or political affiliation alone; people are individuals. They don't fit neatly into "little boxes", he said. "The glory of being human cannot be captured by any one narrow categorization."