The study of argumentation concerns two aspects: reasoning and dialogue.

Argumentation as a form of reasoning  makes explicit the reasons for the conclusions that are drawn and how conflicts between reasons are resolved. This provides a natural mechanism to handle exceptions, to reason with uncertain or conflicting information sources, and to deal with conflicting reasons for belief or action. In consequence, argumentation has become a key topic in the logical study of commonsense reasoning, resulting in logical formalisms that are rigid enough to be formally studied and implemented, while at the same time being close enough to informal reasoning to be understood by designers and users. We study logical formalisations of and algorithms for argumentation-based inference, and we study their application to various domains of commonsense reasoning, such as legal reasoning and crime investigation.

An example dialogue showing the mapping of natural language to speech acts.

In dialogical models of agent interaction, argumentation is important when a conflict of opinion arises between negotiating or collaborating agents. Agents may disagree, for instance, about the pros and cons of alternative proposals, or they may disagree about the factual basis of such proposals. Argumentation as a kind of dialogue provides a natural mechanism for the resolution of such disagreements. We design and study protocols for dialogues with argumentation, as well as strategies for agents that are involved in such dialogues. We also study their application in multi-agent systems, argumentation support systems and other areas.