  In possible worlds semantics, a sentence’s truth-value depended on the world at which it is evaluated. However, indexicals bring in a second dimension – so we need to generalize again. Kaplan (1989) defines the character of a sentence B to be a function from the set of (linguistic) contexts to the content (or intension) of B, where the content, in turn, is simply the intension of B, that is a function from possible worlds to truth-values. Here, truth evaluation is doubly dependent – on both linguistic contexts and possible worlds.