Propositional Attitudes: Fregean Representation and Simulative Reasoning

Abstract

This paper describes briefly a general notation that has been constructed for representing Information about propositional attitudes, and a method that Is being developed for using this notation to reason about such Information. The notation Is Fregean In spirit, and Is based on McCarthy's first-order theory of Individual concepts and propositions, extended to permit adequate representation of Iterated propositional attitudes, and with a semantically simpler representation of quantified propositions and "definite-description" concepts of Individuals. The notation provides a systematic and Intuitively motivated way of dealing with apparent failures of extensionality and quantification Into Intentional constructions . The reasoning method Is knowledge-based, and uses a program's own ordinary Inferential apparatus to "simulate" the reasoning of other Intelligent organisms. The method thus avoids any need for redundant rerepresentatlon of Information about propositions at higher levels In the hierarchy of concepts, and provides a natural approach to making realistic Inferences about the propositional attitudes of others. Toplca and Key Wordaa Representation of knowledge, formal representations, propositional attitudes , Intentional contexts, reasoning about knowledge and belief.