ABSTRACT
There are two ways of looking at the pattern of human activities which lead to very different conclusions concerning both its explanation and the possibilities of deliberately altering it. Of these, one is based on conceptions which are demonstrably false, yet are so pleasing to human vanity that they have gained great influence and are constantly employed even by people who know that they rest on a fiction, but believe that fiction to be innocuous. The other, although few people will question its basic contentions if they are stated abstractly, leads in some respects to conclusions so unwelcome that few are willing to follow it through to the end.
