According to him...
According to him, the earth floated on water, magnet had life because it could move iron, water is the origin of all things, and all things are full of gods. How he came to these last two conclusions is not known now, nor was it known in antiquity, but the connection of his doctrine of water with Homeric Okeanos is evident. No one knows if he set down these ideas in writing, but if he did, no writing of his has survived.
Anaximander The second of these Milesian philosophers was Anaximander, a younger contemporary and disciple of Thales. He and a non‑Milesian Pherecydes were the first two Greeks who wrote in prose. For him the first principle from which arose by eternal motion the heavens, the worlds, the divinities that encompass the earth‑a cylindrically shaped centre of all these worlds and all other things indeed, is an infinite, indeterminate, eternal, all‑enfolding, and all‑controlling stuff.
From this indeterminate something are separated off the opposites, dry and moist, warm and cold, and these form nature with its separate elements (air, water, fire, and earth) and opposite qualities which are held in just balance by time. A sphere of flame formed round the air surrounding the earth, like a bark round a tree, broke off into certain balls, thus forming the sun, the moon, and the stars.
All living beings arose on the earth by gradual development out of the elementary moisture under the drying influence of heat. The first living being that appeared thus was a fish. Anaximenes The third Ionian philosopher of Miletus was Anaximander's disciple Anaximenes. He wrote just one book of which only one complete sentence has survived. The originative substance, according to him, is one, infinite, and not indefinite but definite. It is air which changes by condensation and rarefaction.
In its finest form it is fire; in being made thicker, it becomes wind, then cloud, then water, then earth, and then stones; and the rest, things and gods, come into being from these. Hot and cold are also due to the same processes, the rarefied being hot and the condensed cold. The earth which is flat and round like a plate rides on air. The heaven is a vault that moves round the earth as a cap round the head.
The heavenly bodies are fire raised on high, some fixed like nails in the crystalline vault, others moving like “fiery leaves.” Heraclitus With another Ionian philosopher, Heraclitus, the problem of philosophy shifted from the nature of substance to that of change.