Full Idea
Two virtues that are ordinarily kept distinct - theoretical and practical wisdom - are joined by Plato; he thinks that neither one can be fully possessed unless it is combined with the other.
Gist of Idea
Plato, unusually, said that theoretical and practical wisdom are inseparable
Source
report of Plato (works [c.375 BCE]) by Richard Kraut - Plato
Book Reference
'Encyclopedia of Classical Philosophy', ed/tr. Zeyl,Donald J. [Fitzroy Dearborn 1997], p.405
A Reaction
I get the impression that this doctrine comes from Socrates, whose position is widely reported as 'intellectualist'. Aristotle certainly held the opposite view.