Paul Pietroski

Many concepts, which can be constituents of thoughts, are somehow indicated with words that can be constituents of sentences. But this assumption is compatible with many hypotheses about the concepts lexicalized, linguistic meanings, and the relevant forms of composition. The lexical items simply label the concepts they lexicalize, and that composition of lexical meanings mirrors composition of the labeled concepts, which exhibit diverse adicities. If a phrase must be understood as an instruction to conjoin monadic concepts that correspond to the constituents, lexicalization must be a process in which non-monadic concepts are used to introduce monadic analogues. But given such analogues, along with some thematic concepts, conjunctions can mimic the effect of saturating polyadic concepts. The lexical items efface conceptual adicity distinctions, making it possible to treat a recursive combination of expressions as a sign of monadic predicate conjunction.

Frege's account of opacity is based on two attractive ideas: every meaningful expression has a sense (Sinn) that determines the expression's semantic value (Bedeutung); and the semantic value of a‘that’‐clause is the thought expressed by its embedded sentence. Considerations of compositionality led Frege to a more problematic view: inside ‘that’‐clauses, an expression does not have its customary Bedeutung. But contrary to initial appearances, compositionality does not entail a familiar substitutivity principle. And Fregeans can exploit this point in a way that lets them reject Bedeutung‐shifting.

How can a speaker can explain that P without explaining the fact that P, or explain the fact that P without explaining that P, even when it is true (and so a fact) that P? Or in formal mode: what is the semantic contribution of 'explain' such that 'She explained that P' can be true, while 'She explained the fact that P' is false (or vice versa), even when 'P' is true? The proposed answer is that 'explained' is a semantically monadic predicate, satisfied by events of explaining. But 'the fact that P' (a determiner phrase) and 'that P' (a complementizer phrase) get associated with different thematic roles, corresponding to the distinction between a thing explained and the content of a speech act.