Strategising in Dialogues Handling Forward Extension of Enthymemes

Andreas Xydis, Ionut Moraru, Elizabeth Sklar

Abstract: A common assumption for argumentation-based dialogues is that any argument exchanged is complete, i.e. its premises entail its claim. However, in real world dialogues, agents commonly exchange enthymemes - arguments with incomplete logical structure. This paper expands a previous dialogue system which accommodates enthymemes whose premises do not directly entail the claim of the intended argument, by broadening the way participants reveal its missing elements. It also provides a rational strategy for them to generate a dialogue, without making assumptions for the argument their counterpart intends when they move an enthymeme. Such dialogue will terminate while its moves will have the correct acceptability status. Thus, we capture more realistic scenarios of how a dialogue may unfold and we provide a specific method for computational systems to address such cases, ensuring that the dialogue outcome is the appropriate one.