Situation Theory Reconsidered

Abstract

We recall a largely forgotten intellectual project: that of providing a formal theory of situations that does justice to informal ideas about situations and information flow with the ‘situation theory’ community of the late 1980s and early 1990s. Instead of defending specific desiderata, and in the spirit of Barwise’s ‘Branch Points’, we record some difficulties that defined the project by posing a series of twelve questions. Drawing on the theory of channels and information flow (Barwise and Seligman, late 1990s), with some modifications and extensions, we provide a version of situation theory that answers some of these questions. One of the main extensions is to allow probabilistic constraints. We also consider a more recent proposal by van Benthem to capture many of situation theory’s insights using a modal logic closely related to dependency logic and use this as an alternative but comparable way of answering our questions.