Abstract

The central point of this thesis is the semi-formal approach to contexualist semantics of knowledge by David Lewis. Lewis introduces a set of rules that allow us to ignore certain parts of the space of all possibilities when we evaluate a knowledge claim. These rules are dependent on the context of utterance of the knowledge claim and therefore give rise to a contextualist notion of knowledge. We focus in particular on the Rule of Attention. The open nature of this rule poses problems for a formalisation in the usual framework of dynamic epistemic logic. We make a distinction between two modelling approaches: open modelling and closed modelling. The latter approach, called finite narrative modelling, is a methodology that relieves us from the duty of using a language that can represent arbitrary facts, since we as modellers know which facts will become relevant when we start with the modelling. We introduce two extensions of dynamic epistemic logic and conclude by considering Lewis' rules as restrictions of this model.