Full Idea
An important step towards becoming a person is the step up from a first-order intentional system to a second-order system (which has beliefs and desires about beliefs and desires).
Gist of Idea
Being a person must involve having second-order beliefs and desires (about beliefs and desires)
Source
Daniel C. Dennett (Kinds of Minds [1996], Ch.5)
Book Reference
Dennett,Daniel C.: 'Kinds of Minds' [Phoenix 1997], p.159
A Reaction
Call it 'meta-thought'. I agree. Dennett thinks language is crucial to this, but the hallmark of intelligence and full-blown personhood is meta- and meta-meta-thought. Maybe the development of irony is a step up the evolutionary scale. Sarcasm is GOOD.