Full Idea
The idea of a proposition is unhelpful, until it is explained how exactly the words in the contained sentence manage to name or describe a proposition (which even Frege failed to achieve).
Clarification
'Propositions' are supposed mental entities underlying statements
Gist of Idea
Propositions explain nothing without an explanation of how sentences manage to name them
Source
Donald Davidson (Davidson on himself [1994], p.232)
Book Reference
'A Companion to the Philosophy of Mind', ed/tr. Guttenplan,Samuel [Blackwell 1995], p.232
A Reaction
It seems obvious to me that there are brain events best labelled as propositions, even if their fit with language is puzzling.