Speech Acts, Epistemic Planning and Grice's Maxims

Work on speech acts has generally involved the introduction of sets of different actions such as informing, reminding, bluffing and lying. These actions have different preconditions and effects, and hence can be used to achieve a wide variety of different real-world goals. The problem is that they tend to have indistinguishable surface forms. As such, it is extremely difficult for the hearer to decide which action she thinks has been performed, and it is therefore also extremely difficult for the speaker to be confident about how the hearer will respond. We will show how to achieve complex goals on the basis of a very simple set of linguistic actions. These actions have clearly marked surface forms, and hence can easily be distinguishable by a hearer. In order to do this, we have developed an epistemic planner with a number of interesting features, and with a number of optimisations that relate directly to aspects of the task at hand.