Chapter XVIII. What the Stoics Think Concerning the Conflagration of the Universe

[ARIUS DIDYMUS] ‘But the oldest of this sect are of opinion that all things are changed into ether, when at certain very long periods all are resolved into an ethereal fire.’

And afterwards he adds:

‘But from this it is manifest that Chrysippus has not accepted this confusion in reference to substance (for that was impossible), but only that which was meant as equivalent to change. For the term destruction is not properly understood of the great destruction of the world which takes place in long periods by those who hold the doctrine of the dissolution of the universe into fire, which they call conflagration, but they use the term destruction (fqora&n)as equivalent to change in the course of nature.

‘For it is held by the Stoic philosophers that the universal substance changes into fire, as into a seed, and coming back again, from this completes its organization, such as it was before. And this is the doctrine which was accepted by the first and oldest leaders of the sect, Zeno, and Cleanthes, and Chrysippus. For the Zeno who was the disciple and successor of Chrysippus in the School is said to have doubted about the conflagration of the universe.’