Full Idea
The materialist theory Armstrong and I proposed joins claims of type-type psychophysical identity with a behaviourist or functionalist way of characterising mental states such as pain.
Gist of Idea
Type-type psychophysical identity is combined with a functional characterisation of pain
Source
David Lewis (Mad Pain and Martian Pain [1980], §III)
Book Reference
Lewis,David: 'Philosophical Papers Vol.1' [OUP 1983], p.124
A Reaction
Armstrong has backed off from 'type-type' identity, because the realisations of a given mental state might be too diverse to be considered of the same type. Putnam's machine functionalism allows the possibility of dualism.