Belief Revision and Dynamic Logic

Abstract

We explore belief change policies in a modal dynamic logic that explicitly delineates knowledge, belief, plausibility and the dynamics of these notions. Taking a Kripke semantics counterpart to Grove semantics for AGM as a starting point, we analyse belief in a basic modal language containing epistemic and doxastic modalities. We critically discuss some philosophical presuppositions underlying various modelling assumptions commonly made in the literature, such as the limit assumption and negative introspection for knowledge. Finally, we introduce in the language a general dynamic mechanism and define various policies of iterated belief expansion, revision, contraction and two-dimensional belief change operations.