Full Idea
Either a syllable and its letters are equally knowable and expressible in a rational account, or they are both equally unknowable and inexpressible.
Gist of Idea
Parts and wholes are either equally knowable or equally unknowable
Source
Plato (Theaetetus [c.364 BCE], 205e)
Book Reference
Plato: 'Theaetetus', ed/tr. Waterfield,Robin [Penguin 1987], p.123
A Reaction
Presumably you could explain the syllable by the letters, but not vice versa, but he must mean that the explanation is worthless without the letters being explained too. So all explanation is worthless?