How to change a person's mind: Understanding the difference between the effects and consequences of speech acts

This paper discusses a planner of the semantics of utterances, whose essential design is an epistemic theorem prover. The planner was designed for the purpose of planning communicative actions, whose effects are famously unknowable and unobservable by the doer/speaker, and depend on the beliefs of and inferences made by the recipient/hearer. The fully implemented model can achieve goals that do not match action effects, but that are rather entailed by them, which it does by reasoning about how to act: state-space planning is interwoven with theorem proving in such a way that a theorem prover uses the effects of actions as hypotheses. The planner is able to model problematic conversational situations, including felicitous and infelicitous instances of bluffing, lying, sarcasm, and stating the obvious. 1