Full Idea
Every general idea is purely intellectual. The least involvement of the imagination thereupon makes the idea particular.
Gist of Idea
General ideas are purely intellectual; imagining them is immediately particular
Source
Jean-Jacques Rousseau (Discourse on the Origin of Inequality [1754], Part I)
Book Reference
Rousseau,Jean-Jacques: 'The Basic Political Writings', ed/tr. Cress,Donald A. [Hackett 1987], p.50
A Reaction
This thought is in Berkeley, who seemed to think that general ideas were impossible, because imagination was always required. Rousseau is certainly an improvement on that.
Related Ideas
Idea 6714 Universals do not have any intrinsic properties, but only relations to particulars [Berkeley]
Idea 6719 No one will think of abstractions if they only have particular ideas [Berkeley]