Full Idea
With those numbers that can be grasped only in thought, ..each one is equal to every other, without the least difference and containing no internal parts.
Gist of Idea
In pure numbers, all ones are equal, with no internal parts
Source
Plato (The Republic [c.374 BCE], 526a)
Book Reference
Plato: 'Complete Works', ed/tr. Cooper,John M. [Hackett 1997], p.1142
A Reaction
[Two voices in the conversation are elided] Intriguing and tantalising. Does 13 have internal parts, in the platonist view? If so, is it more than the sum of its parts? Is Plato committed to numbers being built from indistinguishable abstract units/