„Defeasible Reasoning“ und die Fragmentierung der deontischen Logik

Abstract

My contribution starts with an analysis of the structure of normative argumentation, which is understood as the balancing of normative arguments that leads to normative judgements. Its crucial point is that normative arguments and normative judgements have distinct logical structures, and that normative judgements do not follow logically from a set of premises, but result from an act of judgement. Based on this analysis, three theses are advanced: The Inadequacy thesis, stating that neither deductive nor nondeductive (non-monotonic) logic provides an adequate account for the reasoning with conflicting normative arguments. The Fragmentation thesis, suggesting that deontic logic should be developed as a formal characterization of diverse notions of validity of norms and hence there is no single deontic logic. The Deductivity thesis, claiming that normative reasoning from the internal point of view of someone making normative judgements is in its core deductive, and non-monotonic or defeasible reasoning is, from this perspective, merely a deficient form of reasoning. Finally, it is asked what might be a field of application of defeasible reasoning in the field of legal argumentation, and a suggestion is made regarding the notion of defeasibility.