242 HISTORY OF THE of all ancient astronomy ; for his own knowledge of mathematics could not have reached as far as the Pythagorean theorem. He is said to have been the first teacher of such problems as that of the equality of the angles at the base of an isosceles triangle. In the main, the tendency of Thales was practical ; and, where his own knowledge was insufficient, he applied the discoveries of nations more advanced than his own in natural science. Thus he was the first who advised his countrymen, when at sea, not to steer by the Great Bear, which forms a considerable circle round the Pole; but to follow the example of the Phoenicians (from whom, according to Herodotus, the family of Thales was descended), and to take the Lesser Bear for their Polar star.* Thales was not a poet, nor indeed the author of any written work, and, consequently, the accounts of his doctrine rest only upon the testimony of his contemporaries and immediate successors ; so that it would be vain to attempt to construct from them a system of natural philosophy according to his notions. It may, however, be collected from these traditions that he considered all nature as endowed with life: "Everything (he said) is full of gods;"f and he cited, as proofs of this opinion, the magnet and amber, on account of their magnetic and electric properties. It also appears that he considered water as a general principle or cause ; J probably because it sometimes assumes a vapoury, sometimes a liquid form ; and therefore affords a remarkable example of a change of outward appearance. This is sufficient to show that Thales broke through the common prejudices produced by the impressions of the senses; and sought to discover the principle of external forms in moving powers which lie beneath the surface of ap- pearances. § 5. Anaximander, also a Milesian, is next after Thales. It seems pretty certain that his little work "upon nature" (-rrep) (pvcrewg), — as the books of the Ionic physiologers were mostly called, — was written in Olymp. 58, 2, b.c. 547, when he was sixty-four years old.§ This may be said to be the earliest philosophical work in the Greek language ; for we can scarcely give that name to the mysterious revelations of
- This constellation was hence called $««/*». See Schol. Arat. Phoen. 39. Probably-
some traditions of this kind served as the basis, of the vavrixb ao-r^oXoy'ioc, which was attributed to Thales by the ancients, but, according to a more precise account, was the work of a later writer, Phocius of Samos. -j- In the passage of Aristotle, de Anima, i. 5. the words ?t«vt« sj-Xjjjm hZ* Mat, alone express the traditional account of the doctrine of Thales; the words s» o<o rhv ^vvni fAi/MxSat are the gloss of Aristotle. J 'Agjcft, aiTicc. The expression u^x/i was first used by Anaximander. § From the statement of Apollodorus, that Anaximaiuler was sixty-four years old in Olymp. 58. 2. (Diog. Laert. ii. 2), and of Pliny (N. H. ii. 8.), that the obliquity of the ecliptic was discovered in Olymp. 58, it may be inferred that Anaximander mentioned this year in his work. Who else could, at that time, have registered such discoveries ?
