_Ibid._ p. 137. This theory marks in some respects an advance upon that of Empedokles. It was a happy thought of Anaxagoras to make sensation depend upon irritation by opposites, and to connect it with pain. Many modern theories are based upon a similar idea. That Anaxagoras regarded the senses as incapable of reaching the truth of things is shown by the fragments preserved by Sextus. But we must not, for all that, turn him into a sceptic. The saying preserved by Aristotle[731] that “things are as we suppose them to be,” has no value at all as evidence. It comes from some collection of apophthegms, not from the treatise of Anaxagoras himself; and it had, as likely as not, a moral application. He did say (fr. 21) that “the weakness of our senses prevents our discerning the truth,” but this meant simply that we do not see the “portions” of everything which are in everything; for instance, the portions of black which are in the white. Our senses simply show us the portions that prevail. He also said that the things which are seen give us the power of seeing the invisible, which is the very opposite of scepticism (fr. 21_a_). Footnote 731: _Met._ Δ, 5. 1009 b 25 (R. P. 161 a). CHAPTER VII THE PYTHAGOREANS [Sidenote: The Pythagorean school.] 138. We have seen (§ 40) how the Pythagoreans, after losing their supremacy at Kroton, concentrated themselves at Rhegion; but the school founded there was soon broken up. Archippos stayed behind in Italy; but Philolaos and Lysis, the latter of whom had escaped as a young man from the massacre of Kroton, betook themselves to continental Hellas, settling finally at Thebes. We know from Plato that Philolaos was there some time during the latter part of the fifth century, and Lysis was afterwards the teacher of Epameinondas.[732] Some of the Pythagoreans, however, were able to return to Italy later on. Philolaos certainly did so, and Plato implies that he had left Thebes some time before 399 B.C., the year in which Sokrates was put to death. In the fourth century, the chief seat of the school is at Taras, and we find the Pythagoreans heading the opposition to Dionysios of Syracuse. It is to this period that Archytas belongs. He was the friend of Plato, and almost realised, if he did not suggest, the ideal of the philosopher king. He ruled Taras for years, and Aristoxenos tells us that he was never defeated in the field of battle.[733] He was also the inventor of mathematical mechanics. At the same time, Pythagoreanism had taken root in Hellas. Lysis, we have seen, remained at Thebes, where Simmias and Kebes had heard Philolaos, and there was an important community of Pythagoreans at Phleious. Aristoxenos was personally acquainted with the last generation of the school, and mentioned by name Xenophilos the Chalkidian from Thrace, with Phanton, Echekrates, Diokles, and Polymnestos of Phleious.