The Dynamic Turn in Epistemic Logic

This article describes the historical development of epistemic logic, focusing on the dynamic turn that has taken place in the last few decades. Although this dynamic turn was mainly motivated by technical considerations in computer science and game theory, it is argued that it can also be relevant from a more philosophical perspective: the application of dynamic epistemic logics to analyze prima facie static notions, theorems, etc. fits perfectly in a Wittgensteinian approach to philosophy as conceptual elucidation. Furthermore, it turns out that these conceptual elucidations often lead to a number of other advantages, such as a higher degree of empirical adequacy. In order to illustrate this line of argumentation, the system of public announcement logic is presented, and it is shown how this system can be used to analyze the psychological phenomenon of surprise in a conceptually and empirically fruitful way.