(Θαλῆς), the Ionian philosopher, was born at Miletus in the 35th Olympiad, according to Apollodorus (D. L. 1.37). He is said (Hdt. 1.74) to have predicted the eclipse of the sun, which happened in the reign of the Lydian king Alyattes (according to Oltmann's calculations, in the , 1812, 1813, in the year B. C. 609), and under Croesus to have managed the diversion of the course of the Halys (Hdt. 1.75), and later, in order to unite and strengthen the Ionians when threatened by the Persians, to have instituted a federal council in Teos (Ib. 170). These statements, and the mention of Thales in the books of Xenophanes and Heracleitus (D. L. 1.33) accord very well with the reckoning of Apollodorus. which may have been founded on the statement of Demetrius Phalereus, that Thales received the appellation of the Sage in the time of the Athenian archon Damasius (D. L. 1.22). They confirm at the same time the statements respecting the long duration of his life, which extended to 78, or even 90 years (D. L. 1.38). In the different lists of the seven sages his name seems to have stood at the head (D. L. 1.41, &100.22; comp. Cic. Ac. 2.37), and, as his wisdom is said to have shown itself in political sagacity, so also it manifested itself in prudence in acquiring wealth (Arist. Eth. Nic. 1.1, comp. D. L. 1.26). And, generally speaking, the above honourable designation which was given to those seven men, denoted, not scientific inquirers, but men of sound understanding, and famed for their legislative talents, as Dicaearchus had already remarked (D. L. 1.10; Cic. Lael. 2 ; Plut. Solon. 3). Nevertheless Thales is also brought forward as the originator of philosophy and mathematics (ἀρχηγὸς τῆς φιλοσοφίας, Arist. Metaph. 1.3; D. L. 1.28, &c. ; Apul. Flor. c. iv. p. 38, Beroald), and with good reason, if he first convinced himself of the necessity of scientific proof. and attempted it in philosophy and mathematics. In the latter science we find attributed to him only proofs of propositions which belong to the first elements of geometry, and could not possibly have put him in a position to calculate the eclipses of the sun, and the course of the heavenly bodies. Nevertheless, that careful inquirer, Eudemus of Rhodes, had attributed to him both these calculations and those proofs (Diog. Laert. l.c. ; Procl. in Euclid. i. p. 10.17, 19, 44, 67, 79, 92). It is possible that communications from the East, where greater progress had been made in astronomy, came to the help of the Milesian. The Peripatetic Hieronymus had already mentioned his stay in Egypt, which was devoted to mathematical pursuits (D. L. 1.27 ; comp. Plin. Nat. 36.18). Others had attributed to him journeys to Crete and Asia D. L. 1.47. 24. ib. Menag.). In his dogma that water is the origin of things, that is, that it is that out of which every thing arises, and into which every thing resolves itself, Thales may have followed Orphic cosmogonies (Arist. l.c. ; Justin Mart. Coh. ad Gr. p. 7, Paris; Plut. Placit. 1.3, &c.; comp. Ch. A. Brandis, Handbuch der griechisch-römischen Philosophic, i. p. 65, &c.), while, unlike them, he sought to establish the truth of the assertion. Hence, Aristotle, immediately after he has called him the originator of philosophy, brings forward the reasons which Thales was believed to have adduced in confirmation of that assertion; for that no written development of it, or indeed any book by Thales, was extant, is proved by the expressions which Aristotle uses when he brings forward the doctrines and proofs of the Milesian (ἴσως, l.c., de Anim. 1.5; φασίν, de Caelo, 2.13). nay, even in connection with the above-mentioned story (Polit. 1.11; comp. Plat. Thcact. 174, λέγεται). In other ways, also, it is established that Thales left behind him nothing in a written form (D. L. 1.23; Themist. Orat. 26.317, Hard.; Simpl. in Arist. de An. f. 8); a metrical work on astronomy, attributed to him, was regarded even in antiquity as the production of a Samian of the name of Phocas (D. L. 1.23). Verses in which Thaletic doctrines and expressions were embodied (D. L. 1.34; Plut. de Pyth. Orat. p. 402e) belonged without doubt to a later period, and to attribute commentaries (ἀπομνημονεύματα) to him or his school, is an error into which Joannes Philoponus has been led merely by the words of Aristotle which he explains (ἐξ ὧν ἀπομνημονεύουσιν, de Anim. 1.2). Still, we can as little assume that Aristotle attributed the doctrines and their proofs to Thales from mere conjecture; he attaches much too decided an importance to them for that. Besides, Theophrastus seems to have repeated and somewhat modified them; and Eudemus had distinctly stated the mathematical propositions, for which Thales adduced proofs. That the fruit and seeds of things are moist, and that warmth is developed out of moistness, are the reasons which Aristotle regards as those which may have led Thales to the assertion that water is the origin of things. Simplicius (in Arist. Phys. f. 6) adds, probably after Theophrastus, to whom he refers immediately before and after, that what dies, dries up, and that water is what holds all things together : and further, that water is in the highest degree plastic (εὐτύπωτον). The sayings also attributed by Aristotle to Thales, that every thing is full of gods (de Anim. 1.5, p. 411. 70, Berol.), and that the soul is what originates motion, whence also he attributed soul to the magnet (ib. 1.2, p. 405. 19). betray the presupposition that it is by virtue of the indwelling power with which it is pervaded, as with a soul, that water produces the various phenomena. But neither the doctrine of the soul of the universe (Stob. Ecl. Phys. i. p. 54, Heeren ; Plut. Plac. 1.20), nor that of a Deity forming the universe (Cic. de Nat. Deor. 1.10; Joh. Philop. in Arist. de An. p. 7) which later writers attributed to him, can be inferred therefrom : they have here, as in other cases, defined more precisely, or amplified the cautious statements of Aristotle, and perhaps of Theophrastus (in all probability the only authentic sources which they had for the doctrines of Thales), and so make him teach that the soul is that which is moved eternally and by itself (Plut. Plac. 4.2), and immortal (D. L. 1.24), that matter is infinitely divisible (Stob. Ecl. Phys. i. p. 319, &c.) and without void space (ib. 378), that out of water first of all the four elements developed themselves (Herael. Pont. Allcg. Hom. 100.22) and so forth, propositions which, as may be shown, Plato, Empedocles, and others were the first to lay down.