Indexical Expressions in the Scope of Attitude Verbs

A sentential theory of attitudes holds that propositions (the things that agents believe and know) are sentences of a representation language. Given such a theory, it is natural to suggest that the proposition expressed by an utterance of natural language is also a sentence of a representation language. This leads to a straightforward account of the semantics of attitude verbs. However, this kind of theory encounters problems in dealing with indexicals: expressions such as "L" "here," and "now." It is hard to explain how an indexical in the scope of an attitude verb can be opaque. This paper suggests that while the propositions that agents believe and know are sentences, the propositions expressed by utterances are not sentences: they are singular propositions, of the type used in Kaplan's theory of direct reference. Drawing on recent work in situation semantics, this paper shows how such a theory can describe the semantics of attitude verbs and account for the opacity of indexicals in the scope of these verbs.