Triviality and interrogative embedding: context sensitivity, factivity, and neg-raising

Why do predicates like know embed both declarative and interrogative clauses, whereas closely related ones like believe only embed the former? The standard approach following Grimshaw (Linguist Inq 10:279–326, 1979) to this issue has been to specify lexically for each predicate which type of complement clause it can combine with. This view is challenged by predicates such as be certain, which embed interrogative clauses only in certain contexts. To deal with this issue, this paper proposes (i) a novel, unified semantics for declarative and interrogative embedding and (ii) a theory where embedding is constrained by semantic considerations. The reason for the apparent unembeddability of an interrogative clause under a given predicate is the resulting trivial meaning of the sentence. Such triviality manifests itself in unacceptability. Crucially, it is affected by both the lexical meaning of the predicate and the polarity of the sentence as a whole.