Full Idea
In machine functionalism, pain tokens (individual instances of pain) are identical with particular neurophysiological states, but pain itself, the kind, universal, or 'type', can be identified only with something more abstract.
Clarification
A one pound coin is one 'token' of a general 'type'
Gist of Idea
Instances of pain are physical tokens, but the nature of pain is more abstract
Source
report of Hilary Putnam (The Mental Life of Some Machines [1967]) by William Lycan - Introduction - Ontology p.6
Book Reference
'Mind and Cognition (2nd Edn)', ed/tr. Lycan,William [Blackwell 1999], p.6
A Reaction
This is where the "what is it like?" question seems important. Pain doesn't seem like a physical object, or an abstract idea. Personally I think the former is more likely to be correct than the latter. Causation by pain is not like causation by gravity.