Arist. _Met._ i. 3; 983 b 6. Most of the early students of philosophy thought that first principles in the form of matter, and only these, are the sources of all things; for that of which all things consist, the antecedent from which they have sprung, and into which they are finally resolved (in so far as being underlies them and is changed with their changes), this they say is the element and first principle of things. 983 b 18. As to the quantity and form of this first principle, there is a difference of opinion; but Thales, the founder of this sort of philosophy, says that it is water (accordingly he declares that the earth rests on water), getting the idea, I suppose, because he saw that the nourishment of all beings is moist, and that warmth itself is generated from moisture and persists in it (for that from which all things spring is the first principle of them); and getting the idea also from the fact that the germs of all beings are of a moist nature, while water is the first principle of the nature of what is moist. And there are some who think that the ancients, and they who lived long before the present generation, and the first students of the gods, had a similar idea in regard to nature; for in their poems Okeanos and Tethys were the parents of generation, and that by which the gods swore was water,—the poets themselves called it Styx; for that which is most ancient is most highly esteemed, and that which is most highly esteemed is an object to swear by. Whether there is any such ancient and early opinion concerning nature would be an obscure question; but Thales is said to have expressed this opinion in regard to the first cause. Arist. _de Coelo_ ii. 13; 294 a 28. Some say that the earth rests on water. We have ascertained that the oldest statement of this character is the one accredited to Thales the Milesian, to the effect that it rests on water, floating like a piece of wood or something else of that sort.[1] Arist. _de Anima_ i. 2; 405 a 19. And Thales, according to what is related of him, seems to have regarded the soul as something endowed with the power of motion, if indeed he said that the loadstone has a soul because if moves iron. i. 5; 411 a 7. Some say that soul is diffused throughout the whole universe; and it may have been this which led Thales to think that all things are full of gods.