Propositional attitude

Propositional attitude is the cognitive or emotional attitude towards a proposition, which is expressed by a verb or adjective, like know, believe, hope, fear, etc. Propositional attitude verbs create opaque contexts. Indefinite noun phrases in such a context are ambiguous between a de re and de dicto reading:

(i) The farmer believes that a witch blighted his donkey

The farmer either has a de re belief about a specific witch which he holds responsible for blighting his donkey or he has a de dicto belief that some unidentified witch did this.

Links
Utrecht Lexicon of Linguistics