ALL I KNOW - A STUDY IN AUTOEPISTEMIC LOGIC

Current approaches to formalizing nonmonotonic reasoning using logics of belief require the definition of new metalogical properties over sets of sentences. This research attempts to show how some of these patterns of reasoning can be captured using only the classical notions of logic (satisfiability, validity, implication). This is done by extending a logic of belief so that it is possible to say that only a certain proposition (or finite set of them) is believed. This research also extends previous approaches to handle quantifiers and equality, provides a semantic account of certain types of nonmonotonicity and, through a simple proof theory, allows formal derivations to be generated. © 1990.