IN Civil Wars, Rosellen Brown's stunning novel on southern race relations, a black friend says of Teddy Carll, a white liberal intellectually trapped in the 1960s: "He's in love with pessimism." Today people couldn't care less whether your friends are black, another chum remarks, "when they would have frozen you out--or burned you out, even better--fifteen years ago." But, for Teddy, time has stood still, and pessimism is an essential ingredient in his continuing commitment to the civil rights cause.