The essay discusses the import of the separability thesis both for legal positivism and for contemporary legal practice. First, the place of the separability thesis in legal positivism will be explored, distinguishing between “standard positivism” and “post‐Hartian positivism.” Then I will consider various kinds of relations between law and morality that are worthy of jurisprudential interest, and explore, from a positivist point of view, what kind of relations between law and morality must be rejected, what kind of such relations should (...) be taken into account, and what kind of such relations are indeed of no import at all. The upshot of this analysis consists in highlighting the distinction between two different dimensions of legal validity (formal validity and material validity respectively), and in pointing out that the positivist separability thesis can apply to formal validity only. On the other hand, when the ascertainment of material validity is at stake, some form of moral reasoning may well be involved (here and now, it isnecessarilyinvolved). The essay concludes with some brief remarks on the persisting importance of the positivist jurisprudential project. (shrink)

ABSTRACT Inspired by legal reasoning, this paper presents a semantics and proof theory of a system for defeasible argumentation. Arguments are expressed in a logic-programming language with both weak and strong negation, conflicts between arguments are decided with the help of priorities on the rules. An important feature of the system is that these priorities are not fixed, but are themselves defeasibly derived as conclusions within the system. Thus debates on the choice between conflicting arguments can also be modelled. The (...) semantics of the system is given with a fixpoint definition, while its proof theory is stated in dialectical style, where a proof takes the form of a dialogue between a proponent and an opponent of an argument: an argument is shown to be justified if the proponent can make the opponent run out of moves in whatever way the opponent attacks. (shrink)

The author discusses a number of issues in the theory of legal sources. The first topic is whether sources should be conceived of as acts or texts. The alternatives are connected with two competing theories of legal interpretation (viz., the cognitive theory and the sceptical theory), which entail different concepts of legal rules and law‐making. The second topic is whether a “formal” or a “material” criterion of recognition of sources should be preferred. The third section is devoted to the analysis (...) of rules of change. Four theories of rules of change are discussed, and five kinds of such rules are distinguished. The fourth section concerns judicial law‐making, with special reference to the creation of new legal rules by constitutional courts. (shrink)

This article examines the role of normative hierarchies in constitutional argumentation. A threefold distinction between formal, material, and axiological hierarchy is employed. The correlative concepts of formal validity, material validity, and applicability are also briefly described. Within this framework, four cases are analysed: Decisions 1146/1988 and 10/2010 of the Italian Constitutional Court, and Kadi I and Opinion 2/2013 of the Court of Justice of the European Union. As a result, it is argued that axiological hierarchies are frequently used to reshape (...) certain fundamental legal arrangements, namely, the hierarchy of sources (Decision 1146/1988 and Kadi), competence clauses (Decision 10/2010), and interpretive methodologies (Opinion 2/13). (shrink)