Invited Speakers

September 8: Types of Dialogue and Burdens of Proof

Douglas Walton (Assumption University Chair in Argumentation Studies, University of Windsor)



Burden of proof has recently come to be a topic of interest in argumentation systems for artificial intelligence (Prakken and Sartor, 2006, 2007, 2009; Gordon and Walton, 2007, 2009), but so far the main work on the subject seems to be in that type of dialogue which has most intensively been investigated generally, namely persuasion dialogue. The most significant exception is probably deliberation dialogue, where some recent work has begun to tentatively investigate burden of proof in that setting. In this paper, I survey work on burden of proof in the artificial intelligence literature on argumentation, and offer some thoughts on how this work might be extended to the other types of dialogue recognized by Walton and Krabbe (1995) that so far do not appear to have been much investigated in this regard.


September 9: Abstract Dialectical Frameworks

Gerhard Brewka (University of Leipzig)


We present abstract dialectical frameworks, a powerful generalization of Dung-style argumentation frameworks where each node comes with an associated acceptance condition. Acceptance conditions allow us to model different types of dependencies, e.g. support and attack, and their interactions in a flexible manner. We show that Dung's standard semantics can be generalized to dialectical frameworks, in case of stable and preferred semantics to a slightly restricted class which we call bipolar frameworks.
We discuss how acceptance conditions can be conveniently represented using weights, respectively priorities, on the links. We also demonstrate how well-known legal proof standards can be modeled based on this idea.
To demonstrate the usefulness of our approach, we show how the Carneades system proposed by Gordon, Prakken and Walton can be reconstructed as a dialectical framework. This allows us to handle arbitrary cycles in Carneades, providing Carneades with the standard Dung semantics.

We gratefully acknowledge support by
University of Brescia
University of Brescia
Municipality of Desenzano del Garda
Municipality of
Desenzano del Garda
Taylor & Francis
Taylor & Francis Group