The semantics of question-embedding predicates

The complementation pattern of certain question-embedding predicates, such as know and agree, presents a puzzle for the compositional semantics of clausal complementation, as the predicates seem to be able to combine with two distinct types of semantic objects: propositions and questions. The traditional approach to the semantics of these predicates, where embedded questions are reduced to propositions, faces two problems. First, it cannot account for the observation that know-wh sentences require the subject not to believe any false answer to the embedded question. Second, it makes a problematic prediction concerning the interpretation of Predicates of Relevance, such as care and matter. We review three alternative approaches to the semantics of question-embedding predicates, i.e., the proposition-to-question reduction, the uniform approach and the ambiguity approach, and argue that only the Proposition-to-Question reduction and the uniform approach can deal with the interpretation of the Predicates of Relevance. The paper concludes with a remark on how lexical denotations of question-embedding predicates are constrained in general.