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
Jean-Jacques Rousseau (Discourse on the Origin of Inequality , Part I)
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.
Rousseau,Jean-Jacques: 'The Basic Political Writings', ed/tr. Cress,Donald A. [Hackett 1987], p.50
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]