Full Idea
If virtue is some sort of knowledge, then clearly it could be taught.
Gist of Idea
If virtue is a type of knowledge then it ought to be taught
Source
Plato (Meno [c.376 BCE], 87c)
Book Reference
Plato: 'Protagoras and Meno', ed/tr. Guthrie,W K C [Penguin 1956], p.141