Read "Of Those Sentiments Concerning Nature with Which Philosophers Were Delighted" by Plutarch online for free on Textopian. Full text with search, annotations, highlights, and AI-powered reading aids.
The Stoics pronounce that the world is one thing, and this they say is the universe and is corporeal.
Empedocles's opinion is, that the world is one; yet by no means the system of this world must be styled the universe, but that it is a small part of it, and the remainder is idle matter.