In this paper we will analyse the issue of defeasibility in the law, taking into account research carried out in philosophy, artificial intelligence and legal theory. We will adopt a very general idea of legal defeasibility, in which we will include all different ways in which certain legal conclusions may need to be abandoned, though no mistake was made in deriving them. We will argue that defeasibility in the law involves three different aspects, which we will call inference‐based defeasibility, process‐based (...) defeasibility, and theory‐based defeasibility. Only the integration of these three perspectives allows us to provide a satisfactory account of the role of defeasibility in legal reasoning. (shrink)

This article presents a formal dialogue game for adjudication dialogues. Existing AI & law models of legal dialogues and argumentation-theoretic models of persuasion are extended with a neutral third party, to give a more realistic account of the adjudicator’s role in legal procedures. The main feature of the model is a division into an argumentation phase, where the adversaries plea their case and the adjudicator has a largely mediating role, and a decision phase, where the adjudicator decides the dispute on (...) the basis of the claims, arguments and evidence put forward in the argumentation phase. The model allows for explicit decisions on admissibility of evidence and burden of proof by the adjudicator in the argumentation phase. Adjudication is modelled as putting forward arguments, in particular undercutting and priority arguments, in the decision phase. The model reconciles logical aspects of burden of proof induced by the defeasible nature of arguments with dialogical aspects of burden of proof as something that can be allocated by explicit decisions on legal grounds. (shrink)

The phenomenon of defeasibility has long been a central theme in legal literature. This essay aims to shed new light on that phenomenon by clarifying some fundamental conceptual issues. First, the most widespread definition of legal defeasibility is examined and criticized. The essay shows that such a definition is poorly constructed, inaccurate and generates many problems. Indeed, the definition hides the close relationship between legal defeasibility and legal interpretation. Second, this essay argues that no new definition is needed. I will (...) show that from an interpretative standpoint, there is nothing special about legal defeasibility. Contrary to what some authors maintain, no unique or privileged source of legal defeasibility exists, nor are there privileged arguments to justify it. Specifically, legal defeasibility refers to interpretative outcomes deriving from interpretative arguments that, on the one hand, are very different from one another, and, on the other, are often employed to justify different interpretative outcomes. In the legal field, the problems related to defeasibility have little in common with the problems that this label covers in other areas—such as logic or epistemology—and they are nothing but the well-known problems related to legal interpretation. In conclusion, this paper argues that as far as legal argumentation is concerned, the notion of legal defeasibility lacks explanatory power, and it should be abandoned. (shrink)

The article presents possible applications of Paul Ricoeur’s theory in interpretation of legal texts and legally relevant human action. One should notice that Paul Ricoeur developed a comprehensive interpretation theory of two seemingly distant phenomena: literary texts and human action. When interrelating these issues, it becomes possible, on the basis of Ricoeur’s work, to construct a unified theory of the interpretation of legal texts and of legally relevant human action. What is provided by this theory for jurisprudence is the possibility (...) of formulating a comprehensive theory of application of law, well established in the ontology of the recipient of the legal text. It should be emphasised that the resulting benefits, outlined in the article become particularly noticeable when set against the background of the methodological weaknesses of legal positivism, concerning both the interpretation of law and a syllogistic model of its application. (shrink)

The classification of a state of affairs under a legal category can be considered as a kind of con- densed decision that can be made explicit, analyzed, and assessed us- ing argumentation schemes. In this paper, the controversial conflict of opinions concerning the nature of “marriage” in Obergefell v. Hodges is analyzed pointing out the dialecti- cal strategies used for addressing the interpretive doubts. The dispute about the same-sex couples’ right to marry hides a much deeper disa- greement not only (...) about what mar- riage is, but more importantly about the dialectical rules for defining it. (shrink)

The paper consists of three parts. In the first part five kinds of defeasibility are distinguished that is ontological, conceptual, epistemic, justification and logical defeasibility. In the second part it is argued that from these, justification defeat is the phenomenon that plays a role in legal reasoning. In the third part, the view is defended that non-monotonic logics are not necessary to model justification defeat, but that they are so to speak the natural way to model this phenomenon.

While defeasibility in legal reasoning has been the subject of recent scholarship, it has yet to be studied in the context of judicial opinion. Yet, being subject to appeal, judicial decisions can default for a variety of reasons. Prakken (2001) argued that the defeasibility affecting reasoning involved in adversarial legal argumentation is best analysed as procedural rather than logical. In this paper we argue that the defeasibility of ratio decendi is similarly best explained and modeled in a procedural and dialectical (...) framework. We propose that appeals are best understood as meta-dialogues about the reasoned dialogue occurring in the initial trial. (shrink)