Full Idea
Nothing is good except knowledge of some sort.
Clarification
'Knowledge' here is the Greek word 'epistemé'
Gist of Idea
Only knowledge of some sort is good
Source
Plato (Euthydemus [c.385 BCE], 292b)
Book Reference
Plato: 'Early Socratic Dialogues', ed/tr. Saunders,Trevor J [Penguin 1987], p.349
A Reaction
I've heard it suggested that truth is the only value. This is the Socratic idea that moral goodness is a matter of successful rational judgement. Not convinced, but interesting.