Full Idea
It seems to me that all existing things are created by the alteration of the same thing, and are the same thing.
Gist of Idea
Everything is ultimately a variation of one underlying thing
Source
Diogenes (Apoll) (fragments/reports [c.440 BCE], B02), quoted by Simplicius - On Aristotle's 'Physics' 151.31-
Book Reference
'Ancilla to the Pre-Socratic Philosophers', ed/tr. Freeman,Kathleen [Harvard 1957], p.87