A note on modal logic and possibility theory

Abstract

There are two theories in which the concept of possibility plays an important role—modal logic and possibility theory. The roles are different, and so are the agendas of modal logic and possibility theory. To gain an insight into the differences, a very simple model of modal logic is constructed. The model has the structure of a finite-state system, referred to as the FS-model. The FS-model may be viewed as a simple interpretation of Kripke model—an interpretation which is easy to understand. The FS-model is in the spirit of graph models of modal logic. The FS-model readily lends itself to generalization. Concrete versions of the FS-model serve as examples.