Now Socrates became a hearer of Archelaus the physicist, and giving great honour to the maxim “Know thyself” and having established a large school, held Plato to be the most competent of all his disciples. He left no writings [Sidenote: p. 32.] behind him; but Plato being impressed with all his wisdom[99] established the teaching combining physics, ethics and dialectics. But what Plato laid down is this:-- 16. _About Plato._ Plato makes the principles of the universe to be God, matter and (the) model. He says that God is the maker and orderer of this universe and its Providence.[100] That matter is that which underlies all things, which matter he calls a recipient and a nurse.[101] From which, after it had been set in order, came the four elements of which the cosmos is constructed, to wit, fire, air, earth and water,[102] whence in turn all the other so-called compound things, viz., animals and plants have been constructed. But the model is the thought of God which Plato also calls _ideas_, to which giving heed as to an image in the soul,[103] God fashioned[104] all [Sidenote: p. 33.] things. He said that God was without body or form and could only be comprehended by wise men; but that matter is potentially body, but not yet actively. For that being itself without form or quality, it receives forms and qualities to become body.[105] That matter, therefore, is a principle and the same is coeval with God, and the cosmos is unbegotten. For, he says, it constructed itself out of itself.[106] And in all ways it is like the unbegotten and is imperishable. But in so far as body[107] is assumed to be composed of many qualities and ideas, it is so far begotten and perishable. But some Platonists mixed together the two opinions making up some such parable as this: to wit, that, as a wagon can remain undestroyed for ever if repaired part by part, as even though the parts perish every time, the wagon remains complete; so, the cosmos, although it perish part by part, is yet reconstructed and compensated for the parts taken away, and remains eternal.