This chapter contains sections titled: Introduction On Law and Morality Legal Rights and Legal Principles Law and Legal Systems Deontic Logic and Legal Philosophy Philosophical Doctrines in Latin America Conclusion References.

A considerable number of books and papers have analyzed normative concepts using new techniques developed by logicians; however, few have bridged the gap between the English legal culture and the Continental tradition in legal philosophy. This book addresses this issue by offering an introductory study on the many possibilities that logical analysis offers the study of legal systems. The volume is divided into two sections: the first covers the basic aspects of classical and deontic (...) class='Hi'>logic and its connections, advancing an explanation of the most important topics of the discipline by comparing different systems of deontic logic and exploring some of the most important paradoxes in its domain. The second section deals with the role of logic in the analysis of legal systems by discussing in what sense deontic logic and the logic of norm-propositions are useful tools for a proper understanding of the systematic structure of law. (shrink)

. The current literature in the Artificial Intelligence and Law field reveals uncertainty concerning the potential role of deontic logic in legal knowledge representation. For instance, the Logic Programming Group at Imperial College has shown that a good deal can be achieved in this area in the absence of explicit representation of the deontic notions. This paper argues that some rather ordinary parts of the law contain structures which, if they are to be represented in (...) logic, will call for use of a reasonably sophisticated deontic logic. (shrink)

This is the latest volume in the Workshops in Computing series and contains papers to be presented at the Third International Workshop on Deontic Logic in Computer Science (DEON '96) to be held in Sesimbra, Portugal 11 - 13 January 1996. It contains a variety of contributions covering the relationship between deontic logics, logics of action and normative systems (i.e. systems of or about interacting agents whose behaviour is subject to ideal constraints that may not always be (...) fulfilled in practice). The papers range from the theoretical studies of the logical and conceptual tools needed, to studies of various applications. The resulting volume will be of interest to researchers working in a variety of fields from philosophy, logic and legal theory, through to artificial intelligence and computer/management sciences. (shrink)

Abstract.One of the theses of the present work is that, at the strictly logical and methodological level, practical logic has neither made, nor can it make any contribution to the philosophy of law, since none of the three branches of practical logic that have been taken into account, namely, the logic of norms, deontic logic and legal logic, seems to be theoretically possible. The contribution of practical logic to the analysis of (...) legal language is assessed in terms of both the instruments of analysis elaborated by practical logic, the artificial languages, and the results obtained in two capital subjects, the negations of norms and the permissions. (shrink)

Deontic logic is standardly conceived as the logic of true statements about the existence of obligations and permissions. In his last writings on the subject, G. H. von Wright criticized this view of deontic logic, stressing the rationality of norm imposition as the proper foundation of deontic logic. The present paper is an attempt to advance such an account of deontic logic using the formal apparatus of update semantics and dynamic (...) class='Hi'>logic. That is, we first define norm systems and a semantics of norm performatives as transformations of the norm system. Then a static modal logic for norm propositions is defined on that basis. In the course of this exposition we stress the performative nature of (i) free choice permission, (ii) the sealing legal principle and (iii) the social nature of permission. That is, (i) granting a disjunctive permission means granting permission for both disjuncts; (ii) non-prohibition does not entail permission, but the authority can declare that whatever he does not forbid is thereby permitted; and (iii) granting permission to one person means that all others are committed to not prevent the invocation of that permission. (shrink)

The workshop will discuss new insights in the interaction between logic and law, and more precisely the study of different answers to the question: What role does logic play in legal reasoning? It will present both current challenges and historical perspectives in the relation between logic and law. The perspectives to be discussed involve the interface of the following studies.

There has been a recent surge of work on deontic modality within philosophy of language. This work has put the deontic logic tradition in contact with natural language semantics, resulting in significant increase in sophistication on both ends. This chapter surveys the main motivations, achievements, and prospects of this work.

In this paper, I will discuss some examples of the so-called contrary-to-duty paradox, a well-known puzzle in deontic logic. A contrary-to-duty obligation is an obligation telling us what ought to be the case if something forbidden is true, for example: ‘If she is guilty, she should confess’. Contrary-to-duty obligations are important in our moral and legal thinking. Therefore, we want to be able to find an adequate symbolisation of such obligations in some logical system, a task that (...) has turned out to be difficult. This is shown by the so-called contrary-to-duty paradox. I will investigate and evaluate one kind of solution to this problem that has been suggested in the literature, which I will call the ‘counterfactual solution’. I will use some recent systems that combine not only counterfactual logic and deontic logic, but also temporal logic, in my analysis of the paradox. I will argue that the counterfactual solution has many attractive features and that it can give a fairly satisfactory answer to some examples of the contrary-to-duty paradox, but that it nevertheless has some serious problems. The conclusion is that, notwithstanding the many attractive features of the solution, there seem to be other approaches to the paradox that are more promising. (shrink)

The book under review consists of two parts closely related to its title: I Introduction to Deontic Logic, II Logic and Legal Systems. Each part is divided into chapters. Part I brings the following units: 1. The Language of Logic and the Possibility of Deontic Logic; 2. Paradoxes and Shortcomings of Logic; 3. Norm-propositions, Conditional Norms, and Defeasibility, and Part II the following: 4. Legal Systems and Legal Validity; 5. (...) class='Hi'>Legal Indeterminacy: Normative Gaps and Conflicts of Norms; 6... (shrink)

In Meyer’s promising account [7] deontic logic is reduced to a dynamic logic. Meyer claims that with his account “we get rid of most (if not all) of the nasty paradoxes that have plagued traditional deontic logic.” But as was shown by van der Meyden in [4], Meyer’s logic also contains a paradoxical formula. In this paper we will show that another paradox can be proven, one which also effects Meyer’s “solution” to contrary to (...) duty obligations and his logic in general. (shrink)

Eugenio Bulygin is a distinguished representative of legal science and legal philosophy as they are known on the European continent - no accident, given the role of the civil law tradition in his home country, Argentina. Over the past half-century, Bulygin has engaged virtually all major legal philosophers in the English-speaking countries, including H.L.A. Hart, Ronald Dworkin, and Joseph Raz. Bulygin's essays, several written together with his eminent colleague and close friend Carlos E. Alchourrón, reflect the (...) genre familiar from Alf Ross's On Law and Justice, Hans Kelsen's Pure Theory of Law, and Georg Henrik von Wright's Norm and Action. Bulygin's wide-ranging interests include most of the topics found under the rubric of analytical jurisprudence - interpretation and judicial reasoning, validity and efficacy of law, legal positivism and the problem of normativity, completeness and consistency of the legal system, the nature of legal norms, and the role of deontic logic in the law. The reader will take delight in the often agreeably unorthodox character of Bulygin's views and in his hard-hitting arguments in defence of them. He challenges the received opinion on gaps in the law, on legal efficacy, on permissory norms, and on the criteria for legal validity. Bulygin's essays have been wellnigh inaccessible in the past, appearing in specialized journals, often in Spanish or German. They are now available for the first time in an English-language collection. (shrink)

The purpose of this paper is to develop a class of semantic tableau systems for some dyadic deontic logics. We will consider 16 different pure dyadic deontic tableau systems and 32 different alethic dyadic deontic tableau systems. Possible world semantics is used to interpret our formal languages. Some relationships between our systems and well known dyadic deontic logics in the literature are pointed out and soundness results are obtained for every tableau system. Completeness results are obtained (...) for all 16 pure dyadic deontic systems and for 16 alethic dyadic deontic systems. (shrink)

This volume contains the proceedings of DEON2020/2021, the 15th International Conference on Deontic Logic and Normative Systems that was organized by the Munich Center for Mathematical Philosophy at LMU Munich (Germany) on 21st-24th July, 2021. The biennial DEON conferences are designed to promote interdisciplinary cooperation amongst scholars interested in linking the formal-logical study of normative concepts, normative language and normative systems with computer science, artificial intelligence, linguistics, philosophy, organization theory, and law.

The biennial DEON conferences are designed to promote interdisciplinary cooperation amongst scholars interested in linking the formal-logical study of normative concepts and normative systems with computer science, artificial intelligence, linguistics, philosophy, organization theory and law. In addition to these general themes, DEON 2016 encouraged a special focus on the topic "Reasons, Argumentation and Justification.".

Despite increasing interest in studying arguments from deontic authority of the general form “(1) $$\delta$$ δ is a deontic authority in institution $$\varOmega$$ Ω ; (2) according to $$\delta$$ δ, I should do $$\alpha$$ α, C: therefore, (3) I should do $$\alpha$$ α ”, the state of the art models are not capable of grasping their complexity. The existing sets of critical questions assigned to this argumentation scheme seem to conflate two problems: whether a person is subject to (...) an authority of an institution in the first place and whether the command issued within the context of a particular institution is eventually binding. For this reason, we introduce (1) a set of Basic Critical Questions to scrutinize the former issue, and (2) a set of more detailed questions related to specific features, also referred to as “parameters”, of institutional environments (Intra-Institutional Critical Questions). We identify major elements of institutional environments in which authoritative utterances are made and the crucial parameters of arguments from deontic authority. The selected evidence from the decisions of the Polish Supreme Administrative Court helps us show how these parameters may be used to reconstruct subtypes of this argument scheme, with their associated sets of critical questions. In specific institutional contexts, such detailed schemes are capable of grasping the complexity of appeals to deontic authority and thus should be used rather than general schemes. The reconstruction of argumentation schemes with critical questions shows how particular arguments may successfully be attacked. (shrink)

SOCREAL 2007: International Workshop on Philosophy and Ethics of Social Reality. Sapporo, Japan, 2007-03-09/10. Session 3: Obligation and Rationality.

A contrary-to-duty obligation (sometimes called a reparational duty) is a conditional obligation where the condition is forbidden, e.g. “if you have hurt your friend, you should apologise”, “if he is guilty, he should confess”, and “if she will not keep her promise to you, she ought to call you”. It has proven very difficult to find plausible formalisations of such obligations in most deontic systems. In this paper, we will introduce and explore a set of temporal alethic dyadic (...) class='Hi'>deontic systems, i.e., systems that include temporal, alethic and dyadic deontic operators. We will then show how it is possible to use our formal apparatus to symbolise contrary-to-duty obligations and to solve the so-called contrary-to-duty (obligation) paradox, a problem well known in deontic logic. We will argue that this response to the puzzle has many attractive features. Semantic tableaux are used to characterise our systems proof theoretically and a kind of possible world semantics, inspired by the so-called T× W semantics, to characterise them semantically. Our models contain several different accessibility relations and a preference relation between possible worlds, which are used in the definitions of the truth conditions for the various operators. Soundness results are obtained for every tableau system and completeness results for a subclass of them. (shrink)

The aim of this note is to delineate some new systems of logic which govern the interconnections between two kinds of obligation: moral obligation and legal obligation . In consequence, we shall have in such a logic two kinds of forbideness of premission, and of indifference, but obviously definable in terms of the two obligation operators and negation.

Abstract.The paper offers a critical survey of two main sorts of problems hindering the possibility of conceiving deontic logic as a suitable account of the logical behaviour of (sentences expressing) legal norms. The notion of “legal norm” is viewed as the main source of the first sort of problems: (a) the typological variety of legal norms requires an account both of the differing logical behaviour of (sentences expressing) differing legal norms, and of the relations (...) which might hold amon them; (b) the ontologic, semantic, and epistemic features of legal norms shed doubt on the very attempt to figure out a logical analysis of (sentences expressing) legal norms. The notion of “systemic legal validity” is viewed as the main source of the second sort of problems: Deontic logic does not provide suitable logical tools to account for legal phenomena like enactment, derogation, and conflicts between legal norms which rely on systemic legal validity. (shrink)

Could a computer be programmed to make moral judgments about cases of intentional harm and unreasonable risk that match those judgments people already make intuitively? If the human moral sense is an unconscious computational mechanism of some sort, as many cognitive scientists have suggested, then the answer should be yes. So too if the search for reflective equilibrium is a sound enterprise, since achieving this state of affairs requires demarcating a set of considered judgments, stating them as explanandum sentences, and (...) formulating a set of algorithms from which they can be derived. The same is true for theories that emphasize the role of emotions or heuristics in moral cognition, since they ultimately depend on intuitive appraisals of the stimulus that accomplish essentially the same tasks. Drawing on deontic logic, action theory, moral philosophy, and the common law of tort, particularly Terry's five-variable calculus of risk, I outline a formal model of moral grammar and intuitive jurisprudence along the foregoing lines, which defines the abstract properties of the relevant mapping and demonstrates their descriptive adequacy with respect to a range of common moral intuitions, which experimental studies have suggested may be universal or nearly so. Framing effects, protected values, and implications for the neuroscience of moral intuition are also discussed. (shrink)

John Horty effectively develops deontic logic (the logic of ethical concepts like obligation and permission) against the background of a formal theory of agency. He incorporates certain elements of decision theory to set out a new deontic account of what agents ought to do under various conditions over extended periods of time. Offering a conceptual rather than technical emphasis, Horty's framework allows a number of recent issues from moral theory to be set out clearly and discussed (...) from a uniform point of view. (shrink)

LOGIC, EXPERIENCE, AND SCIENTIFIC METHOD Holmes, The Common Law Radin, Law as Logic and Experience Cardozo, Paradoxes of Legal Science Pound, ...

(See also the separate entry for the volume itself.) This introduction has three parts. The first providing an overview of some main lines of research in deontic logic: the emergence of SDL, Chisholm's paradox and the development of dyadic deontic logics, various other puzzles/challenges and areas of development, along with philosophical applications. The second part focus on some actual and potential fruitful interactions between deontic logic, computer science and artificial intelligence. These include applications of (...) class='Hi'>deontic logic to AI knowledge representation in legal systems, to modelling computer systems where it is expected that sub-ideal states will emerge and require countermeasures, to norm-governed human interactions with computer systems, and to the representation of some features of multi-agent systems where different agent-like computer systems interact with one another. The third and final part briefly groups and previews the papers in the anthology. (shrink)

This paper introduces two new paradoxes for standard deontic logic (SDL). They are importantly related to, but distinct from Ross' paradox. These two new paradoxes for SDL are the simple weakening paradox and the complex weakening paradox. Both of these paradoxes arise in virtue of the underlaying logic of SDL and are consequences of the fact that SDL incorporates the principle known as weakening. These two paradoxes then show that SDL has counter-intuitive implications related to disjunctive obligations (...) that arise in virtue of deontic weakening and in virtue of decisions concerning how to discharge such disjunctive obligations. The main result here is then that theorem T1 is a problematic component of SDL that needs to be addressed. (shrink)

The text examines the status of the truth in the legal norms, trying to answer the questions of whether they can be subject to a truth assessment and, if such an assessment is possible, how a truth value can be attributed to legal norms. To achieve this goal, first of all, the text discusses some basic linguistic conceptions concerning the nature and truth of legal norms and subsequently, a a complex approach is being proposed for attributing truth-value (...) to legal norms. On On the one hand, the latter’s being studied by the methods of deontic logic and theory of possible worlds, and on the other hand, their relation to truth is being explained by semantic anti-realism. (shrink)

The main aim of this paper is to study the notion of conditional right by means of constructive type theory (CTT) which provides the means to develop a system of contentual inferences rather than of syntactic derivations. Moreover, in line with Armgardt, we will first study the general notion of dependence as triggered by hypotheticals and then the logical structure of dependence specific to conditional right. I will develop this idea in a dialogical framework where the distinction between play-object and (...) strategy-object leads to the further distinction between two basic kinds of pieces of evidence and where meanings is constituted by the interaction of obligations and entitlements. The present paper is based on Rahman (2015). However, though the underlying CTT-analysis is the same, the dialogical reconstruction makes use of a new way of linking dialogical logic and CTT. Introduction. (shrink)

The present volume is a sequel to Deontic Logic: Introductory and Systematic Readings : its purpose is to offer a view of some of the main directions of research in contemporary deontic logic. Most of the articles included in Introductory and Systematic Readings represent what may be called the standard modal approach to deontic logic, in which de on tic logic is treated as a branch of modal logic, and the normative concepts (...) of obligation, permission and prohibition are regarded as analogous to the "alethic" modalities necessity, possibility and impossibility. As Simo Knuuttila shows in his contribution to the present volume, this approach goes back to late medieval philosophy. Several 14th century philosophers observed the analogies between deontic and alethic modalities and discussed the deontic interpretations of various laws of modal logic. In contemporary deontic logic the modal approach was revived by G. H. von Wright's classic paper 'Deontic Logic'. Certain analogies between deontic and alethic modalities are obvious and uncontroversial, but the standard approach has often been criticized on the ground that it exaggerates the analogies and tends to ignore those features of normative concepts which distinguish them from other modalities. (shrink)

In this paper, I ask whether mishpat ivri (Jewish Law) is appropriately conceived as a “legal system”. I review Menachem Elon’s use of a “Sources” Theory of Law (based on Salmond) in his account of Mishpat Ivri; the status of religious law from the viewpoint of jurisprudence itself (Bentham, Austin and Kelsen); then the use of sources (and the approach to “dogmatic error”) by halakhic authorities in discussing the problems of the agunah (“chained wife”), which I suggest points to (...) a theory more radical than the “sources” theory of law, one more akin to the ultimate phase of the thought of Kelsen (the “non-logical” Kelsen) or indeed to some form of Legal Realism (with which that phase of Kelsen’s thought has indeed been compared)? I finally juxtapose an account based on internal theological resources (a “Jurisprudence of Revelation”). Downloadable at at http://www.biu.ac.il/JS/JSIJ/jsij1.html. (shrink)

There seems to be no clear consensus in the existing literature about the role of deontic logic in legal knowledge representation — in large part, we argue, because of an apparent misunderstanding of what deontic logic is, and a misplaced preoccupation with the surface formulation of legislative texts. Our aim in this paper is to indicate, first, which aspects of legal reasoning are addressed by deontic logic, and then to sketch out the (...) beginnings of a methodology for its use in the analysis and representation of law.The essential point for which we argue is that deontic logic — in some form or other —needs to be taken seriously whenever it is necessary to make explicit, and then reason about, the distinction between what ought to be the case and what is the case, or as we also say, between the ideal and the actual. We take the library regulations at Imperial College as the main illustration, and small examples from genuinely legal domains to introduce specific points. In conclusion, we touch on the role of deontic logic in the development of the theory of normative positions. (shrink)

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.

In this paper, I set out some basic elements of a deontic logic with an implementation appropriate for handling conflicting legal obligations for purposes of programming autonomous machine agents. Kantian justice demands that the prescriptive system of enforceable public laws be consistent, yet statutes or case holdings may often describe legal obligations that contradict; moreover, even fundamental constitutional rights may come into conflict. I argue that a deontic logic of the law should not try (...) to work around such conflicts but, instead, identify and expose them so that the rights and duties that generate inconsistencies in public law can be explicitly qualified and the conflicts resolved. I then argue that a credulous, non-monotonic deontic logic can describe inconsistent legal obligations while meeting Kant’s demand for consistency in the prescriptive system of public law. Finally, I propose an implementation of this logic via a modified form of “answer set programming,” which I demonstrate with some simple examples. (shrink)

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.

We develop a multi-agent deontic action logic to study the logical behaviour of two types of deontic conditionals: (1) conditional obligations, having the form "If group H were to perform action aH, then, in group F's interest, group G ought to perform action aG" and (2) conditional permissions, having the form "If group H were to perform action aH, then, in group F's interest, group G may perform action aG". First, we define a formal language for multi-agent (...) deontic action logic and a class of consequentialist models to interpret the formulas of the language. Second, we define a transformation that converts any strategic game into a consequentialist model. Third, we show that an outcome a* is a Nash equilibrium of a strategic game if and only if a conjunction of certain conditional permissions is true in the consequentialist model that results from the transformation of that strategic game. (shrink)

Abstract.The authors concentrate on the analysis of the concept of permission. After a general account of differing concepts of permission both with regard to different legal theories and to different legal ideologies, they argue in favour of a “radical” imperativism which leaves no place for permissive norms. Thus, in contrast with the logic of normative language (LNL) purported by Alchourrón and Bulygin, the authors figure out a system of deontic logic ‐ supplemented by devices of (...) the possible world semantics ‐ according to which a normative system (N) is conceived as a set of logical consequences of a certain finite set of basic obligations and no room is left either for the concept of weak permission or for the concept of strong permission. Finally the authors raise some criticisms concerning the view maintained by Alchourron and Bulygin on strong permission.*. (shrink)

Modality and negation, as two important linguistic features used to realise subjectivity, have been investigated within various disciplines, such as logic, linguistics and philosophy, and law. The interaction between modality and negation, as a relatively new and undeveloped domain, has however not been paid due attention in scholarship. This corpus-based study investigates three aspects of their interaction: the differentiation of the deontic value by negation, the categorization of deontic modality in Hong Kong legislation via negation, and (...) distribution patterns of deontic modality, especially distribution patterns of the negation of modality, in Hong Kong legislation. This study shows that negation is a powerful linguistic mechanism not only for determining the nature and functions of modality, but also for determining the value of modality. This study also reveals that negation helps us to investigate the distribution of deontic modality in Hong Kong legislation and hence revisit the legal framework in Hong Kong. A study taking into account the discursive and professional aspects of the interaction between deontic modality and negation will provide a theoretical basis for the natural language processing of modality and negation in legislation and also offer important implications for the study of negation and modality in general contexts. (shrink)