Excerpt on Xenophanes and the Truth Available to Mortals from pages 143-144 

"What if philosophy as a systematic analytical approach did not find its beginnings in mysticism, shamanism, the arcane arts, or religion, nor in the natural sciences such as geometry, astronomy, or physics—but in lawmaking and justice; in other words, the legal profession? It could have evolved out of a resolute reaction against one of the greatest threats to the concept of knowledge, namely the relativity of truth as propounded by Xenophanes of Colophon (c.570-c.470b.c.).

Or if we seek to approach the problem differently, we can ask ourselves: what could have motivated Parmenides, the lawgiver, to create a work so rigorous and abstract that it came to be considered as the first work on logic in the world? For a possible answer, we should find out what kind of sources were available to him, including fellow thinkers who might have made enough impact upon the eleatic to trigger such a forceful response. Several modern writers have seen his work as a repudiation of Heraclitus (c. 540-c. 480 B.C.); others have sought to demonstrate a strong Pythagorean influence upon it. Yet these theories, while being quite popular, are very difficult to prove. Lacking any historical evidence that might support such a connection, interpreters must rely on a linguistic examination of the available text. But the surviving material is too meager, the occurrence of few common words here and there makes it hard to establish who influenced whom. On the other hand , Parmenides and Xenophanes were seen as associates in antiquity, or even as pupil and teacher. Although some have questioned the reliability of these reports— even if they are vouched for by Plato and Aristotle— if we focus on the epistemological ramifications of their teachings, easy parallels can be drawn between the two without having to distort their core ideas. It is clear that both thinkers are concerned with the question of whether knowledge that is reliable or certain is available to human beings."