Experience Based Nonmonotonic Reasoning

Abstract

Within everyday reasoning we often use argumentation patterns that employ the rather vague notion of something being normally true. This form of reasoning is usually captured using Reiter’s Default Logic. However, in Default Logic one has to make explicit the rules which are to be used for reasoning and which are supposed to be normally true. This is a bit contrary to the everyday situation where people use experience to decide what normally follows from particular observations and what not, not using any kind of logical rules at all. To formalize this kind of reasoning we propose an approach which is based on prior experiences, using the fact that something follows normally if this is the case for “almost all” of the available experience.