Full Idea
If an orange visual image is a brain state then, by the indiscernibility of identicals, some brain state must also be orange.
Gist of Idea
If an orange image is a brain state, are some parts of the brain orange?
Source
Jaegwon Kim (Philosophy of Mind [1996], p. 64)
Book Reference
Kim,Jaegwon: 'Philosophy of Mind' [Westview 1998], p.64
A Reaction
I think this is the Hardest of all Hard Questions: how can I experience orange if my neurons haven't turned orange? What on earth is orangeness? I don't believe it is a 'microproperty' of orange objects; it's in us.