From Chapter I., The Milesian School

10. Water
Aristotle and Theophrastos, followed by Simplicius and the doxographers, suggest several explanations of this doctrine. Aristotle gives them as conjectures; it is only later writers that repeat them as if they were quite certain.³⁷ The most probable view seems to be that Aristotle ascribed to Thales the arguments used at a later date by Hippon of Samos in support of a similar thesis.³⁸ That would account for their physiological character. The rise of scientific medicine had made biological arguments popular in the fifth century; but, in the days of Thales, the prevailing interest was not physiological, but meteorological, and it is from this point of view we must try to understand the theory.

Now it is not hard to see how meteorological considerations may have led Thales to adopt the view he did. Of all the things we know, water seems to take the most various shapes. It is familiar to us in a solid, a liquid, and a vaporous form, and so Thales may well have thought he saw the world-process from water and back to water again going on before his eyes. The phenomenon of evaporation naturally suggests that the fire of the heavenly bodies is kept up by the moisture they draw from the sea. Even at the present day people speak of "the sun drawing water." Water comes down again in rain; and lastly, so the early cosmologists thought, it turns to earth. This may have seemed natural enough to men familiar with the river of Egypt which had formed the Delta, and the torrents of Asia Minor which bring down large alluvial deposits. At the present day the Gulf of Latmos, on which Miletos used to stand, is filled up. Lastly, they thought, earth turns once more to water—an idea derived from the observation of dew, night-mists, and subterranean springs. For these last were not in early times supposed to have anything to do with the rain. The "waters under the earth" were regarded as an independent source of moisture.³⁹

37. Met. A, 3. 983 b 22 ; Aet. i. 3, 1 ; Simpl. Phys. p. 36, 10 (R. P. 10, 12, 12 a). The last of Aristotle's explanations, that Thales was influenced by cosmogonical theories about Okeanos and Tethys, has strangely been supposed to be more historical than the rest, whereas it is merely a fancy of Plato's taken literally. Plato says (Theaet. 180 d 2; Crat. 402 b 4) that Herakleitos and his predecessors (οἱ ῥέοντες) derived their philosophy from Homer (Il. xiv. 201), and even earlier sources (Orph. frag. 2, Diels, Vors. 66 B 2). In quoting this suggestion, Aristotle refers it to "some"—a word which often means Plato—and he calls the originators of the theory παμπαλαίους, as Plato had done (Met. A, 3. 983 b 28; cf. Theaet. 181 b 3). This is how Aristotle gets history out of Plato. See Note on Sources, § 2.

38. Compare Arist. De an. A, 2. 405 b 2 (R. P. 220) with the passages referred to in the last note. We now know that, though Aristotle declines to consider Hippon as a philosopher (Met. A, 3. 984 a 3; R. P. 219 a), he was discussed in the Peripatetic history of medicine known as Menon's Iatrika. See §185.

39. The view here taken most resembles that of the "Homeric allegorist" Herakleitos (R. P. 12 a). That, however, is also a conjecture, probably of Stoic, as the others are of Peripatetic, origin.