It is said that Thales the Milesian, one of the seven sages, was the first to take in hand natural philosophy.[23] He said that the beginning and end of the universe was water;[24] for that from its solidification and redissolution all things have been constructed and that all are borne about by it. And that from it also come earthquakes and the turnings about of the stars and the motions of the winds.[25] And that all things are formed and flow in accordance with the nature of the first cause of generation; but that the Divinity is that which has neither beginning nor end.[26] Thales, having devoted himself to the system of the stars and to an enquiry into them, became for the Greeks the first who was responsible for this branch of learning. And he, gazing upon the heavens and saying that he was apprehending [Sidenote: p. 8.] with care the things above, fell into a well; whereupon a certain servant maid of the name of Thratta[27] laughed at him and said: “While intent on beholding things in heaven, he does not see what is at his feet.” And he lived about the time of Crœsus. 2. _Pythagoras._ And not far from this time there flourished another philosophy founded by Pythagoras, who some say was a Samian. They call it the Italic because Pythagoras, fleeing from Polycrates, the tyrant of Samos, took up his abode in a city of Italy and there spent his life. Whose successors in the school did not differ much from him in judgment. And he, after having enquired into physics, combined with it astronomy, geometry and music.[28] And thus he showed that unity is God,[29] and after curiously studying the nature of number, he said that the cosmos makes melody and was put together by harmony, and he first reduced the movement of the seven stars[30] to rhythm and melody. Wondering, however, at the arrangement of the universals,[31] he [Sidenote: p. 9.] expected his disciples to keep silence as to the first things learned by them, as if they were mystæ of the universe coming into the cosmos. Thereafter when it seemed that they had partaken sufficiently of the schooling of the discourses, and could themselves philosophize about stars and Nature, he, having judged them purified, bade them speak. He divided the disciples into two classes, and called these Esoterics and those Exoterics. To the first-named he entrusted the more complete teaching, to the others the more restricted. He applied himself[32] to magic[33] also, as they say, and himself invented a philosophy of the origin of Nature,[34] based upon certain numbers and measures, saying that the origin of the arithmetical philosophy comprised this method by synthesis. The first number became a principle which is one, illimitable, incomprehensible, and contains within itself all the numbers that can come to infinity by multiplication.[35] But the first unit was by hypothesis the origin of numbers, the which is a male monad begetting like a father all the other numbers. In the