XXXVII. First of all, Thales, one of the seven, to whom they say that the other six yielded the preeminence, said that everything originated out of water; but he failed to convince Anaximander, his countryman and companion, of this theory; for his idea was that there was an infinity of nature from which all things were produced. After him, his pupil, Anaximenes, said that the air was infinite, but that the things which were generated from it were finite; and that the earth, and water, and fire, were generated, and that from them was produced everything else. Anaxagoras said that matter was infinite; but that from it were produced minute particles resembling one another; that at first they were confused, but afterwards brought into order by divine intellect. Xenophanes, who was a little more ancient still, asserted that all things were only one single being, and that that being was immutable and a god, not born, but everlasting, of a globular form. Parmenides considered that it is fire that moves the earth, which is formed out of it. Leucippus thought that there was a _plenum_, and a _vacuum_; Democritus resembled him in this idea, but was more copious on other matters: Empedocles adopts the theory of the four ordinary and commonly known elements. Heraclitus refers everything to fire; Melissus thinks that what exists is infinite, immutable, always has existed, and always will. Plato thinks that the world was made by God, so as to be eternal, out of matter which collects everything to itself. The Pythagoreans affirm that everything proceeds from numbers, and from the principles of mathematicians. Now of all these different teachers the wise man will, I imagine, select some one to follow; all the rest, numerous, and great men as they are, will be discarded by him and condemned; but whichever doctrine he approves of he will retain in his mind, being comprehended in the same manner as those things which he comprehends by means of the senses; nor will he feel any greater certainty of the fact of its now being day, than, since he is a Stoic, of this world being wise, being endowed with intellect, which has made both itself and the world, and which regulates, sets in motion, and governs everything. He will also be persuaded that the sun, and moon, and all the stars, and the earth, and sea, are gods, because a certain animal intelligence pervades and passes through them all: but nevertheless that it will happen some day or other that all this world will be burnt up with fire.