Full Idea
Kripke's argument is that the possibility of conscious properties coming apart from material properties shows that they cannot be identical with material properties.
Gist of Idea
If consciousness could separate from brain, then it cannot be identical with brain
Source
report of Saul A. Kripke (Naming and Necessity lectures [1970]) by David Papineau - Thinking about Consciousness 3.3
Book Reference
Papineau,David: 'Thinking about Consciousness' [OUP 2004], p.79
A Reaction
A nice clear and simple summary. How can the possibility of coming apart be demonstrated? Only, it seems, by using our imaginations. But that is quite a good guide in areas we know well, but not in recondite areas like the brain.