 Two-dimensional semantics also has a nice story on the behavior of indexicals in belief contexts. “I believe you are Elvis”, said addressing Elvis, appears to mean something different from “I believe Elvis is Elvis”. I would happily utter the latter but not the former if I believe I am facing an Elvis impersonator. It is hard to avoid the impression that the character of expressions like “you” (or, “yesterday”, “that car”, etc.) makes the difference in such cases.