Abstract

The tense tree method extends Jeffrey’s well-known formulation of classical propositional logic to tense logic (Jeffrey 1991).1 Tense trees combine pure tense logic with features of Prior’s U-calculi (where ‘U’ is the earlier-than relation; see Prior 1967 and the Introduction to this volume). The tree method has a number of virtues: trees are well suited to computational applications; semantically, the tree systems presented here are no less illuminating than model theory; the metatheory associated with tree formulations is often more tractable than that required in a model-theoretic setting; and last but not least the tree method is ideal for pedagogical purposes.