Full Idea
We have, I think, shown the impossibility of Abstract Ideas.
Gist of Idea
Abstract ideas are impossible
Source
George Berkeley (The Principles of Human Knowledge [1710], Intro §21)
Book Reference
Berkeley,George: 'The Principles of Human Knowledge etc.', ed/tr. Warnock,G.J. [Fontana 1962], p.60
A Reaction
He achieves this by an attack on universals, offering the nominalist view that there are only particulars. There seems to be a middle ground, where universals don't actually exist, but there are settled conventional abstraction, beyond particulars.