Relation between Plausible Reasoning and Defeasible Argumentation

摘要

Plausible reasoning and defeasible argumentation are notions, once proposed informal philosophy. In short, plausible reasoning is reasoning deductively on a defeasible basis, while defeasible argumentation is just the opposite, namely, reasoning defeasibly on a solid basis. With these definitions, it turns out that many theories that deal with incomplete, uncertain or inconsistent information can be classified as either plausible reasoning or defeasible argumentation. The paper provides examples of this. The prime purpose of the paper, however, is to investigate the relation between these two fundamentally different types of reasoning, whether they are based on incompatible principles, and if not--and the author finds they are not--how they possibly may be brought together in a theory of (as it should be called) plausible argumentation.