Relevant to philosophy, law, management, and artificial intelligence, these papers explore the applicability of nonmonotonic or defeasible logic to normative reasoning. The resulting systems purport to solve well-known deontic paradoxes and to provide a better treatment than classical deontic logic does of prima facie obligation, conditional obligation, and priorities of normative principles.

These 13 papers collected from several meetings of the Society for Exact Philosophy from 1993-96 take a variety of approaches to the task of integrating normative and defeasible reasoning. While most of the papers propose some version of defeasible deontic logic, a few consider alternatives approaches to solving some of the puzzles of normative reasoning that deontic reasoning has failed to resolve. The authors also describe standard deontic logic. Name index only. Annotation copyrighted by Book News, Inc., Portland, OR

A useful logic in which to specify normative system behaviour, deontic logic has a broad spectrum of possible applications within the field: from legal expert systems to natural language processing, database integrity to electronic contracting and the specification of fault-tolerant software.

"Logic and law have a long history in common, but the influence has been mostly one-sided, except perhaps in the 5th and 6th centuries B.C., where disputes at the market place or in tribunals in Greece seem to have stimulated a lot of reflection among sophistic philosophers on such topics as language and truth. Most of the time it was logic that influenced legal thinking, but in the last 50 years logicians began to be interested in normative concepts and hence in law"--

Several years ago I came across a marvelous little paper in which Hector-Neri Castaneda shows that standard versions of act utilitarian l ism are formally incoherent. I was intrigued by his argument. It had long seemed to me that I had a firm grasp on act utilitarianism. Indeed, it had often seemed to me that it was the clearest and most attractive of normative theories. Yet here was a simple and relatively uncontrover sial argument that showed, with only some trivial assumptions, that the doctrine is virtually unintelligible. The gist of Castaneda's argument is this: suppose we understand act utilitarianism to be the view that an act is obligatory if and only if its utility exceeds that of each alternative. Suppose it is obligatory for a certain person to perform an act with two parts - we can call it 'A & B'. Then, obviously enough, it is also obligatory for this person to perform the parts, A and B. If act utilitarianism were true, we appar ently could infer that the utility of A & B is higher than that of A, and higher than that of B (because A & B is obligatory, and the other acts are alternatives to A & B).

In this volume, John Horty brings to bear his work in logic to present a framework that allows for answers to key questions about reasons and reasoning, namely: What are reasons, and how do they support actions or conclusions?

When a legal rule requires us to drive on the right, notarize our wills, or refrain from selling bootleg liquor, how are we to describe and understand that requirement? In particular, how does the logical form of such a requirement relate to the logical form of other requirements, such as moral requirements, or the requirements of logic itself? When a general legal rule is applied or distinguished in a particular case, how can we describe that process in logical form? Such questions have come to preoccupy modern legal philosophy as its methodology, drawing on the philosophy of logic, becomes ever more sophisticated. This collection gathers together some of the most prominent legal philosophers in the Anglo-American and civil law traditions to analyse the logical structure of legal norms. They focus on the issue of defeasibility, which has become a central concern for both logicians and legal philosophers in recent years. The book is divided into four parts. The first section is devoted to unravelling the basic concepts related to legal defeasibility and the logical structure of legal norms, focusing on the idea that law, or its components, are liable to implicit exceptions, which cannot be specified before the law's application to particular cases. Part two aims to disentangle the main relations between the issue of legal defeasibility and the issue of legal interpretation, exploring the topic of defeasibility as a product of certain argumentative techniques in the law. Section 3 of the volume is dedicated to one of the most problematic issues in the history of jurisprudence: the connections between law and morality. Finally, section 4 of the volume is devoted to analysing the relationships between defeasibility and legal adjudication.

This volume presents the refereed proceedings of the 11th International Conference on Deontic Logic in Computer Science, DEON 2012, held in Bergen, Norway, in July 2012. The 14 revised papers included in the volume were carefully reviewed and selected from 29 submissions. Topics covered include logical study of normative reasoning, formal analysis of normative concepts and normative systems, formal specification of aspects of norm-governed multi-agent systems and autonomous agents, normative aspects of protocols for communication, negotiation and multi-agent decision making, formal representation of legal knowledge, formal specification of normative systems for the management of bureaucratic processes in public or private administration, and applications of normative logic to the specification of database integrity constraints.

Within limits, the law allows for exceptions. Or so we tend to think. In fact, the line between rules and exceptions is harder to draw than it seems. How are we to determine what counts as an exception and what as part of the relevant rule? The distinction has important practical implications. But legal theorists have found the notion of an exception surprisingly difficult to explain. This is the longstanding jurisprudential problem that this book seeks to solve.

This volume presents the refereed proceedings of the 12th International Conference on Deontic Logic and Normative Systems, DEON 2014, held in Ghent, Belgium, in July 2014. The 17 revised papers and the 2 invited papers included in this volume were carefully reviewed and selected from 31 submissions. Topics covered include challenges from natural language for deontic logic; the relationship between deontic and other types of modality: epistemic modality, imperatives, supererogatory, etc.; the deontic paradoxes; the modeling of normative concepts other than obligation and permission, e.g., values; the game-theoretical aspects of deontic reasoning; the emergence of norms; norms from a conversational and pragmatic point of view; and norms and argumentation.