Updated: Jan 21
The philosophical system of Stoicism is divided into three parts.
We typically spend most of our time studying Ethics. But if we want to get the most out of reading the ancient texts we should at least have a rudimentary understanding of their views of physics and logic. I will spend a little time over the next few posts examining Stoic physics. There are two sources that I recommend if you wish to explore these topics further. One is The Lives of Eminent Philosophers by Diogenes Laertius. The other is Stoicism by John Sellers. I am not an expert on the subject but will share some basics, I highly encourage you to read into these texts if you want to know more! If you want to dig deeper here is a paper by Vanessa de Harven.
If we start at the grandest scale possible in the Stoic universe we will see The All (Pan). The All consists of an infinite void and the Cosmos/World (Holon) within the void. The Cosmos is considered to be a living being containing a soul. Our souls are considered to be fragments of this universal soul. Bear in mind however, that Stoicism is a philosophy, and not all Stoics agreed on this view.
143. It is a living thing in the sense of an animate substance endowed with sensation; for animal is better than non-animal, and nothing is better than the world, ergo the world is a living being. And it is endowed with soul, as is clear from our several souls being each a fragment of it. Boethus, however, denies that the world is a living thing. The unity of the world is maintained by Zeno in his treatise On the Whole, by Chrysippus, by Apollodorus in his Physics, and by Posidonius in the first book of his Physical Discourse. By the totality of things, the All, is meant, according to Apollodorus, (1) the world, and in another sense (2) the system composed of the world and the void outside it. The world then is finite, the void infinite.-Diogenes Laertius Book VII