Schemes for Argument from Analogy, Classification, and Precedent

Abstract

Argument from analogy is one of the fundamental forms of argumentation on which many other forms of argument – argument from precedent in law, for example – are based (Gordon, 1995; Weinreb, 2005). Our system of Anglo-American law is based on ratio decidendi , the principle that if a case has been decided by a court in a certain way, then a new case that is similar to it should be decided in the same way. Indeed, argument from analogy is the foundation of all case-based reasoning (CBR) in which the argumentation turns on a comparison of one case to another (Ashley and Rissland, 2003). CBR not only compares one case to another as similar, but also compares cases as more similar to others with respect to a given case, depending on the description of the problem posed in the given case. Thus argument from analogy is an extremely important and fundamental species of argumentation. So much has been written on it, in so many fields, including philosophy, cognitive science, artificial intelligence, linguistics, psychology, law, and computing, that we can barely scratch the surface here. Our more limited aim is to develop tools that can be used to identify the precise form of arguments from analogy, allowing us to better understand its close relationships with other important schemes, especially those representing argument from verbal classification and argument from precedent.