Full Idea
Intentional theory is vacuous as psychology because it presupposes and does not explain rationality or intelligence.
Gist of Idea
Theories of intentionality presuppose rationality, so can't explain it
Source
Daniel C. Dennett (Brainstorms:Essays on Mind and Psychology [1978], p.15?)
Book Reference
Rey,Georges: 'Contemporary Philosophy of Mind' [Blackwell 1997], p.76
A Reaction
Virtually every philosophical theory seems to founder because it presupposes something like the thing it is meant to explain. I agree that 'intentionality' is a slightly airy concept that would probably reduce to something better.