Sowell begins his analysis of visions by quoting Walter Lippmann's astute observation: “At the center of every moral code is a picture of human nature, a map of the universe and a version of the story. To human nature (of the conceived type), in a universe (of the imagined type), after a story (so understood), the rules of the code apply. Sowell argues that social views differ in their fundamental conceptions of the nature of man: “Man's capabilities and limitations are implicitly seen in radically different terms by those whose explicit philosophical, political, or social theories are built on different views.” According to Sowell, proponents of different views conceive “the moral and mental nature of man… so differently that even their respective concepts of knowledge and institutions necessarily differ. Social causation itself is conceived differently, both mechanically and mechanically