To include epistemological questions concerning the validity of sociological knowledge in the sociology of knowledge is somewhat like trying to push a bus in which one is riding. To be sure, the sociology of knowledge, like all empirical disciplines that accumulate evidence concerning the relativity and determination of human thought, leads towards epistemological questions concerning sociology itself as well as any other scientific body of knowledge. As we have remarked before, in this the sociology of knowledge plays a part similar to history, psychology and biology, to mention only the three most important empirical disciplines that have caused trouble for epistemology. The logical structure of this trouble is basically the same in all cases: how can I be sure, say, of my sociological analysis of American middle-class mores in view of the fact that the categories I use for this analysis are conditioned by historically relative forms of thought, that I myself and everything I think is determined by my genes and by my ingrown hostility to my fellowmen, and that, to cap it all, I am myself a member of American middle class?

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