 The two-dimensional framework has been interpreted in different ways for different explanatory purposes. The two most widely accepted applications of two-dimensional semantics target restricted classes of expressions. David Kaplan’s 2D semantic framework for indexicals is widely used to explain conventional semantic rules governing context-dependent expressions like ‘I’, ‘that’, or ‘here’, which pick out different things depending on the context in which the expression is used. And logicians working on tense and modal logic use 2D semantics to characterize the logical implications of operators like ‘now’, ‘actually’, and ‘necessarily’. Such restricted applications of 2D semantics are intended to systematize and explain uncontroversial aspects of linguistic understanding.