Defeasible reasoning is indispensable when dealing with a world full of uncertainties: we constantly draw conclusions that we may reject later in view of new information. Examples are numerous: induction, abduction, inferences on the basis of expert opinion, etc. An intuitive perspective on defeasible reasoning is an argumentative one: an inference is retracted if and only if it cannot be defended against counterarguments.
In my talk I will present joint work with Ofer Arieli (Tel Aviv) in which we introduce a general approach for representing and reasoning with argumentation-based systems. In our framework arguments are represented by Gentzen-style sequents, attacks (conflicts) between arguments are represented by sequent elimination rules, and deductions are made according to the skeptical or credulous semantics developed in the tradition of abstract argumentation. This framework accommodates different languages and logics in which arguments may be represented, allows for a flexible and simple way of expressing and identifying arguments, supports a variety of attack relations (including those that reflect relevance or quantitative considerations), and is faithful to standard methods of drawing conclusions by argumentation frameworks.
If time allows, I will also highlight some recent developments in this line of research such as applications in deontic logic and I will show that argumentation theory may benefit from incorporating proof theoretical techniques inspired by the dynamic proofs of adaptive logics.
- Sequent-Based Logical Argumentation
- PRESENTED BY
- Christian Straßer
- Christian Straßer and Ofer Arieli