Lives and Opinions of Eminent Philosophers

...Eudemus in the history he wrote concerning astrology. Wherefore he says that Xenophanes and Herodotus admired him most of all. Heraclitus and Democritus also testify to this same thing. There are those who assert that he was the first to say that souls are immortal, among whom is the poet Choerilus. He was also the first to discover the course of the sun from solstice to solstice. He was the first, as it pleases some, to say that the lunar orb is compared to the magnitude of the sun and is its seven-hundred-and-twentieth part. He was also the first to call the last day of the month the phthinas [wasting day], that is, the thirtieth. He was also the first to discourse on nature. Aristotle and Hippias are authors for the claim that he thought souls were present even in inanimate things, conjecturing this from the magnet stone and amber. Pamphila relates that he was instructed in the precepts of geometry by the Egyptians, that he was the first to describe a right-angled triangle in a circle, and that he sacrificed an ox (others say this was Pythagoras, as does Apollodorus the calculator). Furthermore, what Callimachus says—that Euphobus the Phrygian discovered the scalene [triangles] and those things that pertain to the speculation of lines—these things he [Thales] increased and propagated. It is agreed that he also provided excellent counsel for the interests of the republic. For when Croesus requested the Milesians as allies, he opposed it, and that fact was later the salvation of the city when Cyrus attained victory. Heraclides relates that he loved a solitary and private life. Some say that he took a wife and begot a son, Cibistus, [while] others say he remained a celibate and adopted his sister’s son. And when asked why he did not busy himself with children, he replied that it was because he was not held by the love of children. When his mother urged him to bind himself in the bonds of matrimony, he said it was still premature. When, as he grew older, she insisted more sharply, he said, "Now it is too late." Hieronymus of Rhodes writes in the second book of his commentaries that, when he wished to show how...