A hundred social scientists and geneticists gathered this week in Alexandria to sort out the meaning of race, and didn't, quite.

They gave it a game effort. They tackled every thorny question stretching across their academic disciplines, the historians hearing about clusters of genetic alleles and the geneticists hearing about race as a power relationship.

They explored the distinction between race and geographic variation. They pondered replacing the word "race" with "ethnic group." They talked about racism, multiculturalism, college diversity goals, racial self-identification in the U.S. Census, micro-ethnic groups, the racialization of Mexican Americans and how come no one ever asks why all the white kids sit together in the cafeteria.

When Leith Mullings, an anthropologist from the City University of New York, sardonically said that "only people of color have race, and only women have gender," everyone knew what she meant.

A professor who argues that race is a biological myth sat next to a professor who wants the U.S. government to pay reparations to African Americans. Their positions are not inconsistent, but they require a bit of explaining. Race is complicated. Nothing in the discussion is black and white.

"It doesn't exist biologically, but it does exist socially," said Alan Goodman, incoming president of the American Anthropological Association, which sponsored the meeting at the Holiday Inn in Old Town.

The event served as a brainstorming session for a $4 million project, funded by the National Science Foundation and the Ford Foundation, to create a traveling museum exhibit on race. If all goes well, the exhibit will debut in two years at the Science Museum of Minnesota, in St. Paul. The working title is "Understanding Race and Human Variation."

Beyond that, things get fuzzy.

If there was a consensus that emerged from two days of conversation, it's the notion that race is a cultural construct. Investigations into the human genome have so far failed to turn up any evidence that there's such a thing as, for example, a Caucasian. Human beings are genetically rather homogeneous compared with other animals. But the lack of biological support for traditional categories of race does not change the fact that race is a lived reality. The exhibit should discuss this "paradox of race/no-race," in the words of anthropologist Micaela diLeonardo.

It will take a long time for people to grasp the illusory nature of race at the biological level, Goodman said. It's like understanding that the Earth isn't flat. It looks flat when you're walking around, but if you go up high enough in an airplane you can see the curvature. Someday, he said, people will no longer be flat-Earthers about race. They will see with different eyes.

He identifies himself, incidentally, as a white person.

"Culturally I'm white-ified," he said. "People see me as white. That has something to do with how I look, but it has nothing to do with biological variation."

The revolution won't happen overnight. Americans in particular are socialized to notice race immediately, to put people in rigid categories, not always with the best of intentions. Race might not exist biologically, but, on the flat Earth, it's very noticeable.

"We live in a culture in which race is a dominant paradigm," Goodman said. "I see human variation in this room, but I don't see race."

There was at least one geneticist on hand who wasn't quite ready to do away with race entirely. "It's been said that race is biologically meaningless, and I disagree with that," Lynn Jorde of the University of Utah told a reporter. He provoked much debate in the meeting with his talk about "clusters" of genetic markers that correspond to geographic origin or ancestry. These clusters are correlated with some traditional concepts of race, he said, though there is too much genetic overlap to support the notion that some people are simply white, black, etc.

Still, talk of any biological element to race drew rebukes from some participants. Evolutionary geneticist Joseph Graves, author of "The Race Myth: Why We Pretend Race Exists in America," said scientists have misunderstood the nature of human genetic variation. It doesn't translate into racial categories. "There are no races in anatomically modern humans," Graves said.

Gary Segura, a political scientist at the University of Iowa, said that people tend to pay far too much attention to just a few of the morphological differences among humans. People vary in dozens of different ways, he said.

"We tend to fetishize the shape of the eyes, the shape of the nose, the color of the skin and the texture of the hair," he said.

But he made a prediction: If all the experts in the world suddenly announced that there's no such thing as race, and if newspapers ran the story on the front page, it still wouldn't change the way whites and blacks interact in Alabama.

The conundrum for the experts is finding a way to explain to the lay public why race doesn't exist in one way but in another way is critically important. There was little sympathy here for creating a "colorblind" society, a notion advanced most often by political conservatives.

At one point Fatimah Jackson, a University of Maryland anthropologist, criticized the government practice of gathering racial statistics. Former U.S. Census Bureau official Kenneth Prewitt stood up and asked if that meant the census should have no question about race. Jackson answered that she didn't know why the government should spend money getting data on something that has no biological basis.

"Civil rights!" someone said.

This was all very stimulating, and intellectually enriching, and by the end of the second day, the Earth didn't seem as flat. But no one would go so far as to call the meeting clarifying.

"It is difficult to sort through," said museum consultant Deborah Mack.

"We welcome this kind of all-over-the-place discussion," said Robert Garfinkle, of the Science Museum of Minnesota, putting the best spin on things.

"How can all this be distilled?" asked one of the organizers, Yolanda Moses, speaking to everyone at the end of Monday's marathon session of talks.

She reminded the participants that the museum people "came here to hear clarity around these issues."

And everyone, of all shades and shapes and textures, laughed.

Social scientists and geneticists gathered in Alexandria this week to take part in a brainstorming session for a museum project on race, sponsored by the American Anthropological Association.