Full Idea
The thought of a secondary quality always carries us back to the sensation which it produces.We give the same name to both, and are apt to confound them.
Gist of Idea
Secondary qualities conjure up, and are confused with, the sensations which produce them
Source
Thomas Reid (Essays on Intellectual Powers 2: Senses [1785], 17)
Book Reference
Reid,Thomas: 'Inquiry and Essays', ed/tr. Beanblossom /K.Lehrer [Hackett 1983], p.185
A Reaction
'Redness', for example. Reid puts the point very nicely. Secondary qualities are not entirely mental; they pick out features of the world, but are much harder to understand than the primary qualities. The qualia question lurks.