Argumentation with Defeasible Conditionals: a Preliminary Report (extended Abstract)

This paper investigates the relation between logics for defeasible conditionals and systems for defeasible argumentation. Starting from the assumption that the construction of arguments and the comparison of incompatible arguments are independent phenomena, it is argued that connict resolution plays a role not only in reasoning with, but also in reasoning about defaults. Since in the latter phase hypothetical reasoning is essential, standard natural-deduction is extended with rules for a defeasible conditional; then Vreeswijk's abstract argumentation system is extended with the notion of a hypothetical argument, after which the two systems are combined.