Full Idea
If any existing thing were different in its own essential nature, and were not the same thing which was transformed in many ways and changed, in no way could things mix with one another.
Gist of Idea
Things must retain their essential nature during change, or mixing would be impossible
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
Related Idea
Idea 17479 The nature of an element must survive chemical change, so it is the nucleus, not the electrons [Hendry]