Logic and probabilistic update

This chapter surveys recent work on probabilistic extensions of epistemic and dynamic-epistemic logics (the latter include the basic system of public announcement logic as well as the full product update logic). It emphasizes the importance of higher-order information as a distinguishing feature of these logics. This becomes particularly clear in the dynamic setting: Although there exists a clear relationship between usual Bayesian conditionalization and public announcement, the probabilistic effects of the latter are in general more difficult to describe, because of the subtleties involved in higher-order information. Finally, the chapter discusses some applications of probabilistic dynamic epistemic logic, such as the Lockean thesis in formal epistemology and Aumann’s agreement theorem in game theory.