Liberal political theory, from Hobbes onward, called on each citizen to view himself as primarily a distinct, autonomous atom, unlinked to his fellow atoms unless he contracts to join them. Christianity, with its emphasis on the separate, irreplaceable value of each human soul, also played a key part in the drama, which came into full flower in the Enlightenment. The careful separating out of each soul from its social background has of course been responsible for an immense amount that is distinctive and valuable in the achievements of our civilization. When other, more direct social motives are weakened human prudence alone turns out quite unequal to the job. Social psychologists have drawn attention to the complex dependence of human individuals on their background. Social, cooperative ideals have to be seen as taking a major, rather than a minor, part in practical argument. The Industrial Revolution, releasing them to become socially mobile, naturally appeared on the whole as a liberat-ing force.