We shall introduce a set of fundamental legal concepts, providing a definition of each of them. This set will include, besides the usual deontic modalities (obligation, prohibition and permission), the following notions: obligative rights (rights related to other’s obligations), permissive rights, erga-omnes rights, normative conditionals, liability rights, different kinds of legal powers, potestative rights (rights to produce legal results), result-declarations (acts intended to produce legal determinations), and sources of the law.

This paper presents in outline Luigi Ferrajoli’s axiomatic and general theory of law, as developed in his lifelong work Principia Iuris . The first section focuses on the three main aspects of the theory: the methodological, the theoretical and the pragmatic, which respectively represent the theory’s syntax, semantics and its pragmatics. Ferrajoli identifies three deontic gaps of norms: firstly, the one between their validity and efficacy ; secondly, the one between their justice and validity ; and finally, and most importantly, (...) the one between validity and existence (i.e. normative force). The presence of such gaps is, according to Ferrajoli, the extraordinary innovation that entrenched constitutions have brought into modern legal systems, by establishing norms that are superior to statutes and case law. In this sense, all normative phenomena (except for the constitution itself) can be conceived both as norms and as facts. In the second section the role of juridical science is briefly discussed. (shrink)

Les juges créent-ils du droit ? Eros Roberto Grau, avocat, ancien professeur à la prestigieuse Faculté de droit de l’Université de São Paulo et ancien membre de la Cour suprême brésilienne de 2004 à 2010, aurait sans aucun doute pu faire un livre inaccessible sur cette question, tant son parcours, ses forts engagements et ses réflexions prolifiques l’y autorisent.Sa biographie est en particulier disponible en brésilien sur le site de la Cour suprême brésilienne et sur son site personnel . Mais (...) le présent ouvrage édité par Carlos Miguel Herrera, « texte de combat » selon son préfacier Antoine Jeammaud, est une invitation à mieux découvrir l’approche critique du droit défendue par l’auteur sous l’angle d’une théorie réaliste de l’interprétation aussi habile qu’originale. Classiquement, selon cette dernière, on ne le sait que trop bien, le droit n’est pas à considérer c .. (shrink)

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)

We discuss similarities and residual differences, within the general semantic framework of minimality, between defeasible inference, belief revision, counterfactual conditionals, updating — and also conditional obligation in deontic logic. Our purpose is not to establish new results, but to bring together existing material to form a clear overall picture.

Pragma-dialectical approaches to legal argumentation seem to be rather different from traditional approaches appealing to standards of propositional logic. Pragma-dialectical analysis of arguments by analogy and e contrario seem to fall foul to the rigors of logical analysis, in which problems or even concepts of analogy and e contrario seem to disappear. The brunt of both types of special legal argumentation appears to be borne by often implicit general principles and an appeal to the system of the law as a (...) whole. Still, pragma-dialectics and logical analysis of legal argument are best seen as fruitfully supplementing each other in ongoing research of ever evolving legal argument. (shrink)

This paper argues the thesis that a particular style of reasoning, qualitative comparative reasoning (QCR), plays a role in at least three areas of legal reasoning that are central in AI and law research, namely legal theory construction, case-based reasoning in the form of case comparison, and legal proof. The paper gives an informal exposition of one particular way to deal with QCR, based on the author’s previous work on reason-based logic (RBL). Then it contains a substantially adapted formalisation of (...) RBL, to make RBL suitable for dealing with QCR. The paper concludes with a brief discussion of related work. (shrink)

This paper proposes a framework for formalising intuitions about the behaviour of imperative commands. It seeks to capture notions of satisfaction and coherence. Rules are proposed to express key aspects of the general logical behaviour of imperative constructions. A key objective is for the framework to allow patterns of behaviour to be described while avoiding making any commitments about how commands, and their satisfaction criteria, are to be interpreted. We consider the status of some conundrums of imperative logic in the (...) context of this proposal. (shrink)

The paper outlines ongoing research on logic-based tools for the analysis and representation of legal contracts, of the kind frequently encountered in large-scale engineering projects and complex, long-term trading agreements. We consider both contract formation and contract performance, in each case identifying the representational issues and the prospects for providing automated support tools.