The philosophical movements of the Twentieth Century included Anglo-American analytic philosophy, Existentialism, Phenomenology, and social and psychological theories that had philosophical implications, such as psychoanalysis and Marxism. But the one I have found the most important philosophical perspective is that of the sociological perspective that developed in mid twentieth century America and Europe that had been based on the earlier generation of American Pragmatism, by Dewey and Nagel, even though the sociologists themselves, such as Paul Lazarsfeld and Robert Merton, were not philosophers but sharp observers and analysts of the social scene. I want to take note of their dominant procedures because they do what all philosophers do, which is to turn ideas about what has to be to go topsy turvy as when they eliminate ideas that are to be regarded as superfluous because they are not necessary ideas, which is the case when Spinoza thought that “justice” and “cause” were unnecessary terms, or thought that terms are to be added as necessary, as when Kant based the idea of free will on the necessary invocation of the word “should” so as to make the world what it is.