Full Idea
The identity theorist has to hold that we are under some illusion in thinking that we can imagine that there could have been pains without brain states.
Gist of Idea
Identity theorists must deny that pains can be imagined without brain states
Source
Saul A. Kripke (Identity and Necessity [1971], p.190)
Book Reference
'Meaning and Reference', ed/tr. Moore,A.W. [OUP 1993], p.190
A Reaction
The origin of Robert Kirk's idea that there might be zombies. Kripke is wrong. Of course Kripke and his friends can imagine disembodied pains; the question is whether being able to imagine them makes them possible, which it doesn't.