Logic and Law

Exceptions to rules play an important role in law, and in particular in international law. A proper understanding of exceptions is therefore of crucial importance for legal practice, legal doctrine and legal theory. The aim of this article is to contribute to this understanding; it is not to describe the law or the present usage with regard to rules and exceptions. As background for the development of a theory about exceptions to rules, sections 3 and 4 go into some detail concerning rules, rule-formulations, legal sources, reasons and their logic. In section 5, we will elaborate on the distinction between the applicability and the application of a rule. A rule is applicable to a case if the rule is valid, and if its ordinary and scope conditions are satisfied by the case. If a rule is applied to a case, the rule attaches its legal consequences to the facts of the case. Normally the applicability of a rule to a case is a contributory reason why the rule should be applied to the case. An exception to a rule in a case is defined as the situation in which a rule is applicable to, but nevertheless not applied to the case. In section 6, two main grounds for making an exception to a rule are identified. First, the maker of the rule may use the rule-exception construction to create a division in the burden of proof. As argued in section 9, this leads to a so-called undercutting defeater. Second, there may be reasons why the legal consequences of the rule in the case are undesirable. This leads to a reason against applying the rule, which needs to be balanced to the applicability of the rule as reason for application. In this situation we speak of rebutting defeaters (see section 9.2). An important reason why it is undesirable to apply a rule to a case is that application would generate a conflict with another applicable rule. Section 8 discusses a number of tools/techniques that can be used to avoid rule conflicts and which would in that way make exceptions superfluous. Finally, the question may be raised whether legal rules really have exceptions. Is it not the case that if a rule is well-formulated, it mentions all 'exceptions' as negative rule conditions? Such a well-formulated 'derived' rule can then be applied deductively to cases that satisfy the rule conditions. In sections 10 and 11, this possibility is discussed and it is shown that this use of derived rules blocks the possibility to model the division of burden of proof which is implicitly given with the rule-exception model. The article is summarized and concluded in section 12.

This paper connects State sovereignty to fragmentation and the potential for inconsistencies and conflicts, investigating whether exercises of sovereignty necessarily lead to inconsistencies that would hinder international cooperation. It argues that this is not the case, essentially because the logic of rules differs fundamentally from the logic of statements, and because this rule logic allows one to find a consistent and workable legal system in a pluralistic and fragmented collection of sources of international law. The paper begins by showing how sovereignty leads to the fragmentation of international law, and fragmentation to inconsistency, increasing the risk for rule conflicts. Thereafter, it pays attention to the traditional conception of consistency by considering the consistency of descriptive sentences. However, it holds that the consistency of descriptive sentences does not fit the nature of rules. While descriptions are true or false as far as they succeed at describing the world, rules are not truth-apt. Rules are valid or invalid to the extent that they succeed on influencing the world. This difference leads the paper to adopt a different definition for the consistency of rules. Following this, the paper considers how adding more rules can remove inconsistency and remove conflicts. It concludes that the addition of rules can help ensure the consistency of the set of rules of international law. Moreover, even if fragmentation as a result of 'unsupervised' exercises of sovereignty by States has occurred, further rule-creation can remove inconsistency or conflict by means of a framework of metarules .