In broad terms a popular belief in "progress" means the rejection of an attitude that has characterized most human communities throughout history. Normally, people have believed that the future would repeat the past. When they have expected that human life was going to change, they have usually supposed that this change was going to take place suddenly and radically, by supernatural intervention. And if they have permitted themselves to hope for the improvement of the human condition, the hope has commonly been directed toward salvation from the world rather than reform of the world. By and large, historical change, when people have been aware of it at all, has been viewed as a sign of mortality and the proof of a lapse from ideal standards. Indeed, in many societies there has been a popular conviction that humankind's condition has changed in the...