COST Action IC0801

Argumentation is the process whereby arguments are constructed and evaluated in light of their interactions with other arguments. The appeal of the argumentation paradigm resides in its intuitive modular characterisation that is akin to human modes of reasoning. Also, recent work in the AI, and computer science community at large, has illustrated the potential for tractable implementations of logical models of argumentation, and the wide range of application of these implementations in software systems. Furthermore, the inherently dialectical nature of argumentation models provide principled ways in which to structure exchange of, and reasoning about, justifications/arguments for proposals and or statements between human and or automated reasoning entities (agents). It is these features that make formal computational models of argumentation particularly suited to their use in agreement technologies. To illustrate, consider the following fictional negotiation dialogue between a buyer and seller of cars in which locutions also involve making, accepting and rejecting offers:

• Seller -  Offer: Cobalt car
• Buyer - Reject: Cobalt car
• Seller - Why?
• Buyer - Argue: Because Cobalt is a Bonland make of car, and Bonland cars are unsafe
• Seller - Argue: Cobalts are not unsafe as Cobalts have been given the award of safest car in Europe by the European Union.
• Buyer - Accept: Cobalt car

The above example illustrates the utility of argumentation based models of reasoning and their application to dialogues. Online negotiations involving automated software agents are a key area of research and development. In a handshaking protocol, a seller would simply successively make offers and have these either rejected or accepted. The exchange of arguments provides for agreements that would not be reached in simple handshaking protocols. In the above example, it is by eliciting the reason for the rejection, and successfully countering this reason, that the seller is then able to convince the buyer to buy the car.

Challenges for Argumentation and Negotiation

The example illustrates a number of challenges to be met if computational models of argumentation are to be successfully deployed in agreement technologies:

1. Validation of such arguments as being internally coherent
2. Validation of the purported relations between arguments (e.g whether one argument validly supports or attacks another argument)
3. Evaluation of arguments in order to determine mutually acceptable agreements

Finally, note that to facilitate automation of such dialogues requires a shared understanding of the concepts and relationships involved. Thus, a key challenge is to situate the use of argumentation in a Semantic Web 2.0 context.