Situation semantics

Situation semantics is a framework in formal semantics and situation theory in which the meanings of linguistic expressions are evaluated with respect to situations—partial, concrete parts or aspects of the world—rather than complete possible worlds. It was developed in the late 1970s and early 1980s by Jon Barwise and John Perry as an alternative to extensional model theory and possible-worlds semantics, with a particular focus on , attitude reports and other context-dependent constructions in natural language.

Situation semantics is underpinned by situation theory, a general mathematical theory of information developed by Barwise, Perry, Keith Devlin and others, which introduces formal objects such as infons (units of information), constraints and types to model how information is carried and flows between situations.

In contemporary formal semantics, situation-based approaches include both the original Barwise–Perry programme and a more widely adopted family of theories (associated especially with Angelika Kratzer) that treat situations as parts of possible worlds and use situation variables in otherwise orthodox possible-worlds semantics.