Jaap Hage

This book features essays that investigate the nature of legal validity from the point of view of different traditions and disciplines. Validity is a fascinating and elusive characteristic of law that in itself deserves to be explored, but further investigation is made more acute and necessary by the production, nowadays, of soft law products of regulation, such as declarations, self-regulatory codes, and standardization norms. These types of rules may not exhibit the characteristics of formal law, and may lack full formal validity but yet may have a very real impact on people's lives. The essays focus on the structural properties of hard and soft legal phenomena and the basis of their validity. Some propose to redefine validity: to allow for multiple concepts instead of one and/or to allow for a gradual concept of validity. Others seek to analyze the new situation by linking it to familiar historical debates and well-established theories of law. In addition, coverage looks at the functions of validity itself. The discussion considers both international law as well as domestic law arrangements. What does it mean to say that something is valid? Should we discard validity as the determining aspect of law? If so, what does this mean for our concept of law? Should we differentiate between kinds of validity? Or, can we say that rules can be "more" or "less" valid? After reading this book, practitioners, scholars and students will have a nuanced understanding of these questions and more. Chapter 6 is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

This book is exceptional in the sense that it provides an introduction to law in general rather than the law of one specific jurisdiction, and it presents a unique way of looking at legal education. It is crucial for lawyers to be aware of the different ways in which societal problems can be solved and to be able to discuss the advantages and disadvantages of different legal solutions. In this respect, being a lawyer involves being able to reason like a lawyer, even more than having detailed knowledge of particular sets of rules. Introduction to Law reflects this view by focusing on the functions of rules and on ways of arguing the relative qualities of alternative legal solutions. Where 'positive' law is discussed, the emphasis is on the legal questions that must be addressed by a field of law, and on the different solutions which have been adopted by, for instance, the common law and civil law tradition. The law of specific jurisdictions is discussed to illustrate possible answers to questions such as when the existence of a valid contract is assumed.

This article describes how the facts in social reality take an intermediate position between objective facts and purely subjective ‘facts’. In turn, these social facts can be subdivided into constructivist and non-constructivist facts. The defining difference is that non-constructivist facts are completely determined by an approximate consensus between the members of a social group, while constructivist facts are founded in such a consensus but can nevertheless be questioned. Ought fact are such constructivist facts. Because they are founded in social reality, a naturalistic theory of ought facts is attractive. Because constructivist facts are always open to questioning, we can explain why the facts in social reality may found ought facts but are nevertheless not the final word about them.

Are the cognitive sciences relevant for law? How do they influence legal theory and practice? Should lawyers become part-time cognitive scientists? The recent advances in the cognitive sciences have reshaped our conceptions of human decision-making and behavior. Many claim, for instance, that we can no longer view ourselves as purely rational agents equipped with free will. This change is vitally important for lawyers, who are forced to rethink the foundations of their theories and the framework of legal practice. Featuring multidisciplinary scholars from around the world, this book offers a comprehensive overview of the emerging field of law and the cognitive sciences. It develops new theories and provides often provocative insights into the relationship between the cognitive sciences and various dimensions of the law including legal philosophy and methodology, doctrinal issues, and evidence.

This contribution elaborates the idea that norms are rules that lead to deontic consequences. Rules are one kind of constraints on possible worlds. They determine which facts necessarily go together or cannot go together. Three kinds of rules are distinguished: dynamic rules which attach consequences to the occurrence of events, fact-to-fact rules which attach one fact to the presence of some other fact, and counts-as rules, which make that some things also count as something else. Deontic facts are facts that tend to induce a motivation to comply with them in agents to which they apply. A distinction is made between two kinds of basic deontic facts—the existence of duties and of obligations—and two kinds of supervening deontic facts: being obligated and owing to do something. Some norms lead to obligations, and others impose duties.

My main claim in this article is that lawyers should make less use of the hermeneutical method than they do. The reasons that I will adduce to support this claim are the following: law is first and foremost an answer to the question of how to act and, more in particular, the question of which rules to enforce by collective means. As such, law does not coincide with positive law. Nevertheless, positive law determines the content of the law to a large extent. It does so for two reasons. The first reason is that positive law contributes to legal certainty and that legal certainty is very important for the question concerning which rules should be enforced by collective means. The second reason is that respect for positive law, which was created by democratic bodies, implies respect for democracy. However, positive law can only contribute to legal certainty if its application is predictable. If positive law can be interpreted in more than one way, its application will not be predictable. In that case, positive law is not relevant for the content of the law tout court. Theories about the interpretation of positive law are particularly relevant where positive law can be interpreted in different ways, that is where positive law is not relevant for the content of the law tout court. Therefore, hermeneutical theories are not relevant for the content of the law and lawyers should not waste their time on them. A similar argument can be given for the democratic legitimation of positive law.

In the law, it is generally acknowledged that there are intuitive differences between reasoning with rules and reasoning with principles. For instance, a rule seems to lead directly to its conclusion if its condition is satisfied, while a principle seems to lead merely to a reason for its conclusion. However, the implications of these intuitive differences for the logical status of rules and principles remain controversial.A radical opinion has been put forward by Dworkin (1978). The intuitive differences led him to argue for a strict logical distinction between rules and principles. Ever since, there has been a controversy whether the intuitive differences between rules and principles require a strict logical distinction between the two. For instance, Soeteman (1991) disagrees with Dworkin's opinion, and argues that rules and principles cannot be strictly distinguished, and do not have a different logical structure.

Much work on legal knowledge systems treats legal reasoning as arguments that lead from a description of the law and the facts of a case, to the legal conclusion for the case. The reasoning steps of the inference engine parallel the logical steps by means of which the legal conclusion is derived from the factual and legal premises. In short, the relation between the input and the output of a legal inference engine is a logical one. The truth of the conclusion only depends on the premises, and is independent of the argument that leads to the conclusion.This paper opposes the logical approach, and defends a procedural approach to legal reasoning. Legal conclusions are not true or false independent of the reasoning process that ended in these conclusions. In critical cases this reasoning process consists of an adversarial procedure in which several parties are involved. The course of the argument determines whether the conclusion is true or false. The phenomenon of hard cases is used to demonstrate this essential procedural nature of legal reasoning.

This paper deals with two issues in the field of reasoning by analogy in the law. The one issue is whether there exists such a thing as analogous rule application, or whether there is only the ‘normal’ application of a broadened rule. It is argued that if rules, as the entities made by a legislator, are distinguished from generalised solutions for cases, the idea of analogous application of rules makes sense. It is also shown how the so-called ‘reason-based model of rule application’, in contrast to the traditional modus ponens or subsumption model, makes it easy to give a logical account of analogous rule application. The other issue is how to argue logically about whether two cases are sufficiently similar to adopt the outcome of the one case for the other case. Section 3 provides a general logical model to establish this. The model is based on the comparison of the reasons for and against a particular solution in the two cases.

Brouwer argued against a vision of the law in which moral considerations partly determine the contents of the law. He did this for moral reasons, mainly because of the uncertainty such a vision would cause. This seems a strange view because it means that the nature of the law would depend on moral considerations concerning legal certainty. Most of the present paper is devoted to exploring two conceptions of the law, law as social fact and law as practical reason. It is argued that a view like Brouwer’s fits in the law as practical reason conception and is therefore not so strange as might seem at first sight

This article argues that it is possible to hold autonomous agents themselves, and not only their makers, users or owners, responsible for the acts of these agents. In this connection autonomous systems are computer programs that interact with the outside world without human interference. They include such systems as ‘intelligent’ weapons and self-driving cars. The argument is based on an analogy between human beings and autonomous agents and its main element asserts that if humans can be held responsible, so can, in principle, autonomous agents, as humans are more like autonomous agents than is often assumed.

This paper develops the theory that a set of rules is consistent if it is not possible that (1) the conditions of the rules in the set are all satisfied, (2) there is no exception to either one of the rules, and (3) the consequences of the rules are incompatible. To this purpose the notion of consistency is generalised to make it cover rules and is relativised to some background of constraints.This theory is formalised by means of Rule Logic, in which rules are treated as constraints on the possible worlds in which they exist. Rule Logic itself is introduced by giving a model-theory for it. It is characterised by means of constraints on worlds that are possible according to Rule Logic.