Full Idea
It is through discourse that the same thing flits around, becoming one and many in all sorts of ways.
Gist of Idea
A thing can become one or many, depending on how we talk about it
Source
Plato (Philebus [c.354 BCE], 15d)
Book Reference
Plato: 'Complete Works', ed/tr. Cooper,John M. [Hackett 1997], p.403
A Reaction
This is not scepticism about wholes on Plato's part, but a reminder of an obvious fact, that in thought we can break the world up and put it back together again. It is a touchstone of the debate, though.