Now That You Mention It - Awareness Dynamics in Discourse and Decisions

Michael Franke, Tikitu de Jager

Abstract: We model unawareness of possibilities in decision making and pragmatic reasoning. A background model is filtered through a state of limited awareness to provide the epistemic state of an agent who is not attending to all possibilities. We extend the standard notion of awareness with assumption (implicit beliefs about propositions the agent is unaware of) and define a dynamic update for ‘becoming aware.’ We give a propositional model and a decision-theoretic model, and show how pragmatic relevance reasoning can be described in the latter. An utterance can be relevant even if semantically uninformative, if it brings relevant alternatives to awareness. This gives an explanation for the use of possibility modals and questions as hedged suggestions, bringing possibilities to awareness but only implicating their degree of desirability or probability.