Abstract: Temporal logic as a modern discipline is separate from classical logic; it is seen as an addition or expansion of the more basic propositional and predicate logics. This approach is in contrast with logic in the Middle Ages, which was primarily intended as a tool for the analysis of natural language. Because all natural language sentences have tensed verbs, medieval logic is inherently a temporal logic. This fact is most clearly exemplified in medieval theories of supposition. As a case study, we look at the supposition theory of Lambert of Lagny (Auxerre), extracting from it a temporal logic and providing a formalization of that logic.
Comment: This article employs modal-temporal logic with Kripke semantics to formalize a particular supposition theory (Lambert of Lagny’s). Thus, it includes an original proposal. Moreover, it provides both an introduction to medieval supposition theory and an introduction to Kripke semantics. So, it could be used as a means to work on either of those topics. It does not involve many technicalities, but a bit of familiarity with modal logic is recommended.