Full Idea
If a mental state is not propositional, then how can it possibly serve as a foundation for belief? How can one infer or justify anything on the basis of a state that, having no propositional content, must be logically dumb?
Gist of Idea
If mental states are not propositional, they are logically dumb, and cannot be foundations
Source
Ernest Sosa (The Raft and the Pyramid [1980], §11)
Book Reference
'Epistemology - An Anthology', ed/tr. Sosa,E. /Kim,J. [Blackwell 2000], p.148
A Reaction
This may be the best objection to foundationalism. McDowell tries to argue that conceptual content is inherent in perception, thus giving the beginnings of inbuilt propositional content. But an organism awash with bare experiences knows nothing.