The Need for New Logical Tools

Abstract

As already indicated in Chapter 2, the untenability of the naive deductivist view on legal reasoning limits the applicability of standard logical methods, for which reason new logical tools are needed. In this chapter I shall in more detail go into the causes of the limitations and the nature of the needed tools. A first cause is the rule-guided rather than rule-governed nature of legal reasoning. Because of the open, unpredictable nature of the world to which the law applies and also because of the many competing interests or moral opinions involved in legal disputes, legal rules are often not followed but put into question: as a consequence, they are often subject to exceptions which are not explicitly stated in legislation, and this calls for ways of representing the provisional or ‘defeasible’ character of legal rules. Section 3.2 will be devoted to this issue. The second source of problems for standard logic also has to do with the fact that the legislator cannot foresee everything: for this reason legal rules often deliberately leave open which factual circumstances classify as instances of the concepts occurring in the rule’s conditions and, consequently, questions of classification often leave room for conflicting opinions. The logical problems to which this gives rise, will be discussed in Section 3.3.