You may think racism means prejudging or discriminating against people because of their race. All right: can you define race? Go on, try it. Or host a party and challenge your guests to come up with an explanation that doesn't start a fight. Is race a biological classification, an ethnic one, a religious one, a geographic one, or what? If the meaning of race is slippery, how precise can this term it feeds - racism - be? And if the definition is what enables us to evaluate the facts, where does all this leave us? Racism today belongs to a...