Book excerpt: In the first philosophical challenge to accepted racial classifications in the United States, Naomi Zack uses philosophical methods to criticize their logic. Tracing social and historical problems related to racial identity, she discusses why race is a matter of such importance in America and examines the treatment of mixed race in law, society, and literature. Zack argues that black and white designations are themselves racist because the concept of race does not have an adequate scientific foundation. The "one drop" rule, originally a rationalization for slavery, persists today even though there have never been "pure" races and most American blacks have "white" genes. Exploring the existential problems of mixed race identity, she points out how the bi-racial system in this country generates a special racial alienation for many Americans. Ironically suggesting that we include "gray" in our racial vocabulary, Zack concludes that any racial identity is an expression of bad faith. Author note: Naomi Zack is Assistant Professor in the Department of Philosophy at the State University of New York at Albany. She herself is of mixed race: Jewish, African American, and Native American.