Formalising arguments about the burden of persuasion.

This paper presents an argument-based logic for reasoning about allocations of the burden of persuasion. The logic extends the system of Prakken (2001), which in turn modified the system of Prakken & Sartor (1996) with the possibility to distribute the burden of proof over both sides in an argument game. First the (2001) system is put in the context of a distinction of three types of proof burdens and it is argued that the proof burdens of that system are in fact burdens of persuasion. Then the (2001) system is modified to allow for defeasible reasoning about allocations of such burdens within the logic. The usefulness of the resulting system is illustrated with applications to real legal cases