Inquirers: A general model of non-ideal rational agents

Doxastic logics have been widely used to model the reasoning processes that a rational agent may perform on its beliefs. The possible worlds model and the Kripke semantics provide an intuitive semantics to doxastic formulas, but they may only be used to model ideal agents. A different model is propo sed in this article. In this new approach, the consistent and complete stan dard possible worlds are replaced by conceivable situations, that are those scenarios that the modelled agent is capable of considering, regardless of their partiality or inconsistency. A general class of non-ideal reasoners, the rational inquirers, is defined, and it is shown how the evolution of t he beliefs of this kind of agents, caused by a multidimensional dynamic ana lysis, may be modelled in the framework of conceivable situations. (C) 2000 John Wiley & Sons, Inc.