Abstract
An information-based approach to natural language semantics. Formulated by Jon Barwise and John Perry in their influential book Situations and Attitudes (1983), it is built upon the notion of a 'situation' --- a limited part of the real world that a cognitive agent can individuate and has access to. A situation represents a lump of information in terms of a collection of facts. It is through the actualist ontology of situations that the meaning of natural language utterances can be elucidated.