Logical Tools for Legal Pluralism

Abstract

The development of the internet, the rise of transnational law, globalization and the existence of different legal traditions next to each other all make that the opportunities for conflicts between rules of different legal systems increase. On the assumptions that the results on different legal systems in one case cannot conflict and exclude each other – the assumption of consistency and the excluded middle – conflicts between legal systems appear problematic. This contribution gives an overview of logical tools that can help to avoid these conflicts, or to deal with them. In this way it hopes to contribute to a use of logic to which Patrick Glenn alluded in the concluding chapter of his classic Legal Traditions of the World.A conflict of rules occurs when it is possible that two or more rules attach incompatible legal consequences to a case. Within a single legal system, the possibility of rule conflicts is limited by adding scope conditions to the ordinary rule conditions. Another limitation of this possibility consists in limiting the powers of rule creating agents.Often it is impossible to create rules that conflict with already existing rules. If there are actually conflicting rules, it becomes necessary to handle the conflict. By adopting a non-deductive logic for rule application it becomes possible to account for exceptions to rules. An exception to a rule makes that a rule which is applicable in a case should nevertheless not be applied. Then the rule does not attach its legal consequences to the case. One reason for making an exception to a rule is that application of the rule would lead to legal consequences which are incompatible with the legal consequences of another applicable rule.If a conflict occurs between rules of different legal systems, there is logically speaking no need to deal with the conflict. It is logically well possible that an agent ought to do X from the point of view of one legal system and ought to refrain from doing X from the point of view of another legal system. However, an agent who is subject to incompatible prescriptions from different legal systems is burdened with a dilemma. Legal systems often come to the assistance of such individuals by referring to the rules of other systems, or by incorporating ‘foreign’ law.