The Role of Logic in Legal Reasoning

Abstract

The aim of this chapter is to illustrate the point of departure of this book that logic should not be regarded as a model of, but as a tool in legal reasoning. I shall do so mainly by discussing some objections to logical methods which can be found in legal philosophy and AI-and-law. Some of them are an application to the legal domain of more general criticism of logic discussed in Chapter 1. Section 2.1 briefly discusses some basic misunderstandings about the nature of logic, after which Section 2.2 examines in more detail another misunderstanding, the opinion that applying logic to legal reasoning would be the same as regarding law as a coherent system of rules which can somehow be discovered and formalized. Then, Section 2.3 deals with the criticism that logical methods can only model a small part of legal reasoning since most forms of reasoning used in law are nondeductive. Finally, Section 2.4 relates the mainly philosophical discussions of the first three sections to an issue in AI-and-law research, the distinction between ‘rule-based’ and ‘case-based’ reasoning.