The fatal error of much science fiction has been to subscribe to an optimism based on the idea that revolution, or a new gimmick, or a bunch of strong men, or an invasion of aliens, or the conquest of other planets, or the annihilation of half the world--in short, pretty nearly anything but the facing up to the integral and irredeemable nature of mankind--can bring about utopian situations. It is the old error of the externalization of evil.