Full Idea
There has been much scepticism about a functionalist account of intentionality, particularly from Putnam (recently) and Searle, but, like many others, I don't see any principled objections to such an account.
Gist of Idea
Intentionality as function seems possible
Source
Jaegwon Kim (Mind in a Physical World [1998], §4 p.101)
Book Reference
Kim,Jaegwon: 'Mind in the Physical World' [MIT 2000], p.101
A Reaction
I agree. I don't believe that intentionality is a candidate for being one of those many 'magic' qualities which are supposed to make the reduction of mind to brain impossible.