Lives and Opinions of Eminent Philosophers

​Thales, then, as Herodotus, Duris, and Democritus say, was the son of Examyes and Cleobuline, belonging to the Thelidae, who are Phoenicians and the noblest among the descendants of Cadmus and Agenor. 〈He was also one of the Seven Sages〉, as Plato too says; and he was the first to be called wise during the archonship of Damasias at Athens, under whom the Seven Sages were also so named, as Demetrius of Phalerum says in his List of Archons. He was enrolled as a citizen in Miletus when he came with Neileus, who had been banished from Phoenicia; though, as most say, he was an indigenous Milesian and of noble birth.

​After his political activity, he turned to the study of nature. According to some, he left no treatise behind; for the Nautical Astronomy attributed to him is said to be by Phocus of Samos. Callimachus, however, knows him as the discoverer of the Little Bear, saying thus in his Iambics: “and he was said to have measured the stars of the Wain, by which the Phoenicians sail.” According to others, he wrote only two treatises, On the Solstice and On the Equinox, having judged the other subjects to be incomprehensible. Some think he was the first to study astronomy and to predict solar eclipses and solstices, as Eudemus says in his History of Astronomical Matters; whence both Xenophanes and Herodotus admire him. Heraclitus and Democritus also bear witness to him.

​Some also say that he was the first to declare that souls are immortal; among whom is Choerilus the poet. He was also the first to discover the passage of the sun from solstice to solstice, and the first, according to some, to declare the size of the sun 〈to be a seven-hundred-and-twentieth part of the solar circle, just as the size of the moon is〉 a seven-hundred-and-twentieth part of the lunar circle. He was also the first to call the last day of the month the “thirtieth.” And he was the first to discuss nature, as some say. Aristotle and Hippias say that he also attributed souls to inanimate objects, drawing his inference from the magnetic stone and amber. And Pamphile says that having learned geometry from the Egyptians, he was the first to inscribe a right-angled triangle in a circle, and that he sacrificed an ox.

​Others, however, say this was Pythagoras, among whom is Apollodorus the calculator. It was this Pythagoras who developed to the fullest extent those things which Callimachus in his Iambics says the Phrygian Euphorbus discovered, such as scalene figures and triangles, and whatever pertains to linear theory. Thales seems also to have given the most excellent counsel in political affairs. At any rate, when Croesus sent envoys to the Milesians proposing an alliance, he prevented it; which deed saved the city when Cyrus prevailed. He himself also says, as Heraclides relates, that he lived as a solitary and private individual.

​Some say he married and had a son Cybisthes; others that he remained unmarried and adopted his sister's son. It is said that when he was asked why he did not have children, he replied: “Because of my love for children.” And they say that when his mother was urging him to marry, he would say: “It is not yet the right time.” Then, when she pressed him after he was past his prime, he said: “It is no longer the right time.” Hieronymus of Rhodes also says, in the second book of his Miscellaneous Notes, that wishing to show that it is easy to become wealthy, when a large olive crop was imminent, he foresaw this and leased all the olive-oil presses, amassing a very great deal of money.

​He posited water as the principle of all things, and held that the cosmos is animate and full of daemons. They say that he discovered the seasons of the year and divided it into three hundred and sixty-five days. No one was his teacher, except that having gone to Egypt he spent time with the priests. Hieronymus also says that he measured the pyramids by their shadows, having observed when our shadow is of equal length to ourselves. He also lived in intimacy with Thrasybulus the tyrant of Miletus, as Minyes says. The circumstances concerning the tripod found by the fishermen and sent round to the wise men by the people of Miletus are well known.