You read an article about repressed memories of sexual abuse returning in middle-age; a television program features actors as villains of a certain build and physiognomy; you chat with a friend about the damage done to their personalities by their parents, siblings, or circumstances; you explain to someone how you forgot a task assigned because of an unconscious motivation. We are all natural psychologists, explaining behavior by the beliefs of our time and culture. We are captives, in a psychological sense, by theories and ideas that we accept tacitly, without knowledge or evaluation of their origins. We do not escape their influence, for they represent our idea of common sense. We can be, however, better evaluators of ourselves and others by examining the ideas' origins and source of their power. To find and judge their source we are powerless if we use only our own sense of reason, for reason is contaminated by ideas of the past.Our best hope is to search for their origins.