  Suppose that John understands sentence (16) and assertively utters (16) while addressing Mary and intending to refer to her. Then, plausibly, John asserts the proposition that (16) semantically expresses in his context. Moreover, if John is sincere, then he believes the proposition that (16) expresses in his context. Thus a semantic theory that describes the content of sentence (16) in John’s context also describes a proposition that he believes. Hence the theory of indexical semantics has implications for the theory of indexical belief. Theories of indexical belief can also have important implications for the semantics of indexicals. If, for instance, speakers do not believe the propositions that a semantic theory assigns to indexical sentences, relative to contexts, then that is prima facie reason to reject that semantic theory.