Evaluating arguments based on Toulmin’s scheme

Toulmin’s argument scheme (1958) represents an influential tool for the analysis of arguments. The scheme enriches the traditional premises-conclusion model of arguments by distinguishing additional elements, like warrant, backing and rebuttal. The present paper contains a formal elaboration of Toulmin’s scheme, and extends it with a treatment of the formal evaluation of Toulmin-style arguments, which Toulmin did not discuss at all. The present work builds on recent research on defeasible arguments (cf. e.g. the work of Pollock, Loui, Vreeswijk and Dung). More specifically, the author' s work on the dialectical logic DEFLOG and the argumentation tool ARGUMED serve as starting points.