Full Idea
Surely we learn something about an object when we discover its secondary qualities? ...If secondary quality experience were informationally inert, its variety would be something of a puzzle. Why not employ the same medium for all primary informaton?
Gist of Idea
Secondary qualities contain information; their variety would be superfluous otherwise
Source
Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6)
Book Reference
McGinn,Colin: 'The Subjective View' [OUP 1983], p.97
A Reaction
This is important. We can't just focus on the primary qualities, and ignore the secondary. But diverse colours draw attention to information, which can then be translated into neutral data, as in spectroscopic analysis. Locke agrees with this.