Full Idea
It is sometimes contended that the whole idea of materialism is somehow empty, on the grounds that there is no proper way to characterize the 'physical' realm.
Gist of Idea
Some suggest that materialism is empty, because 'physical' cannot be properly characterized
Source
report of DH Mellor / T Crane (There is no question of physicalism [1990]) by David Papineau - Thinking about Consciousness 1.1
Book Reference
Papineau,David: 'Thinking about Consciousness' [OUP 2004], p.15
A Reaction
[Papineau also cites Gabriel Segal] I agree with Papineau in rejecting this. Uncertainties about quantum states do not pose a problem, and the position tends to have an implicit dualism buried in it somewhere.