Full Idea
None of Locke, Berkeley or Hume shows any sign of serious thinking about the relation of their concepts of quality, idea or impression to the problem of universals; it is as if they thought this issue had disappeared.
Gist of Idea
Locke, Berkeley and Hume did no serious thinking about universals
Source
comment on John Locke (Essay Conc Human Understanding (2nd Ed) [1694]) by Howard Robinson - Perception 1.4
Book Reference
Robinson,Howard: 'Perception' [Routledge 2001], p.12
A Reaction
Maybe they were right. Personally I think there is a real problem of universals, but the history of philosophy has lots of cases of deep worries about problems that don't seem to bother anyone else.