Full Idea
The inseparability thesis about perception says that for any actual and possible sense the content of experiences delivered by that sense must be both of secondary qualities and of primary qualities.
Gist of Idea
Maybe all possible sense experience must involve both secondary and primary qualities
Source
Colin McGinn (Subjective View: sec qualities and indexicals [1983], 6)
Book Reference
McGinn,Colin: 'The Subjective View' [OUP 1983], p.81
A Reaction
That would mean that all possible experience must have a mode of presentation, and also must be 'of' something independent of experience. So a yellow after-image would not count as an 'experience'?