SOURCE: Charles H. Kahn, "Pythagorean Philosophy Before Plato," in The Pre-Socratics: A Collection of Critical Essays, edited by Alexander P. D. Mourelatos, Anchor Books, 1974, pp. 161-85.

In the following essay, Kahn outlines the critical debate surrounding Pythagoras and his contributions to ancient Greek philosophy, examining the doctrines generally attributed to him and the evidence that might substantiate these attributions.

The name of Pythagoras is not only the most famous, it is also the most controversial in the history of Greek thought before Socrates and Plato. Since antiquity it has been a name to conjure with: There is such a wealth of conflicting evidence concerning Pythagoras' teaching, but so much of this evidence is unreliable. In 1925 A. N. Whitehead could write, in reference to the function of mathematical ideas in abstract thought: "Pythagoras was the first man who had any grasp of the full sweep of this general principle...