Their meaning is that fire, water, earth, and air all exist by nature and chance, and not by art; and that out of these, according to certain chance affinities of opposites, the sun, the moon, the stars, and the earth have been framed, not by any action of mind, but by nature and chance only.

Thus, in their opinion, the heaven and earth were created, as well as the animals and plants.

Art came later, and is of mortal birth; by her power were invented certain images and very partial imitations of the truth, of which kind are the creations of musicians and painters: but they say that there are other arts which combine with nature, and have a deeper truth, such as medicine, husbandry, gymnastic.

Also the greater part of politics they imagine to co-operate with nature, but in a less degree, having more of art, while legislation is declared by them to be wholly a work of art.
'How do you mean ?' In the first place, they say that the Gods exist neither by nature nor by art, but by the laws of states, which are different in different countries; and that virtue is one thing by nature and another by convention; and that justice is altogether conventional, made by law, and having authority for the moment only.

This is repeated to young men by sages and poets, and leads to impiety, and the pretended life according to nature and in disobedience to law; for nobody believes the Gods to be such as the law affirms.