A contrario reasoning (or ‘a contrario argument’ or ‘argument a contrario’) is traditionally understood as an appeal to the deliberate silence of the legislator: because a legal rule does not mention case X specifically, the rule is not applicable to it. Modern perspectives on legal reasoning often apply this label to a broader concept of reasoning, namely the reasoning by which a legal rule is not applied because of the differences between the case at hand and the one(s) mentioned in (...) the legal rule. This article first explains how the broader concept could have come into being, and then argues that from an argumentation theoretical point of view the modern concept makes no sense as a category of argumentation. Furthermore it is shown under which conditions the traditional concept can be sound. (shrink)

This paper deals with two issues in the field of reasoning by analogy in the law. The one issue is whether there exists such a thing as analogous rule application, or whether there is only the ‘normal’ application of a broadened rule. It is argued that if rules, as the entities made by a legislator, are distinguished from generalised solutions for cases, the idea of analogous application of rules makes sense. It is also shown how the so-called ‘reason-based model of (...) rule application’, in contrast to the traditional modus ponens or subsumption model, makes it easy to give a logical account of analogous rule application. The other issue is how to argue logically about whether two cases are sufficiently similar to adopt the outcome of the one case for the other case. Section 3 provides a general logical model to establish this. The model is based on the comparison of the reasons for and against a particular solution in the two cases. (shrink)

SummaryThis contribution offers an evaluation of e contrario reasoning in which the interpretation of a legal rule is based on the context of the law system (contextual e contrario reasoning). A model is presented which will show all the explicit and implicit elements of the argument at work and will also point out how these distinct parts are interrelated. By questioning the content and justificatory power of these elements, the weak spots in the argument can be laid bare. It will (...) be argued that e contrario reasoning inevitably requires a dubious argumentative step, which renders the argument intrinsically weak. The model is applied to a European lawsuit on French cheese. (shrink)

In practical reasoning, reasonableness ‐ as opposed to rationality ‐ is an important concept. This paper explores the notion of reasonableness as applied exclusively to legal decisions. Conflicting values or legal requirements can make rationally deduced solutions unattainable, and may call for criteria of reasonableness, Conflicting values must be weighed, and weighed against each other, in search of a point of equilibrium between them. Legal cases are more or less difficult to solve, depending on the difficulty of finding a unique (...) optimal equilibrium. The relevance of factual and ideal consensus for the determination of a reasonable legal decision is underlined. Finally, a definition of “reasonable legal decision” is proposed. (shrink)

This essay discusses the developments and trends of research in legalargumentation of the last 25 years. The essay starts with a survey of thevarious approaches which can be distinguished: the logical approach, therhetorical approach, and the dialogical approach. Then it identifies varioustopics in the research, which constitute the various components of aresearch programme of legal argumentation: the philosophical component, thetheoretical component, the reconstruction component, the empiricalcomponent, and the practical component. It concludes with a discussion ofthe main trends in the research (...) of the last 25 years. (shrink)

Argument from analogy is a common and formidable form of reasoning in law and in everyday conversation. Although there is substantial literature on the subject, according to a recent survey ( Juthe 2005) there is little fundamental agreement on what form the argument should take, or on how it should be evaluated. Th e lack of conformity, no doubt, stems from the complexity and multiplicity of forms taken by arguments that fall under the umbrella of analogical reasoning in argumentation, dialectical (...) studies, and law. Modeling arguments with argumentation schemes has proven useful in attempts to refine the analyst’s understanding of not only the logical structures that shape the backbone of the argument itself, but also the logical underpinning of strategies for evaluating it, strategies based on the semantic categories of genus and relevance. By clarifying the distinction between argument from example and argument from analogy, it is possible to advance a useful proposal for the treatment of argument from analogy in law. (shrink)

In this paper I investigate the similarities betweenthe dialectical procedure in the pragma-dialecticaltheory and dialectical procedures in AI and Law. I dothis by focusing on one specific type of reasoning inlaw: analogy argumentation. I will argue that analogyargumentation is not only a heuristic forfinding new premises, but also a part of thejustification of legal decisions. The relevantcriteria for the evaluation of analogy argumentationare not to be found at the logical level of inference,but at the procedural level of the discussion. I (...) willproceed as follows. I start with an outline ofPrakken's theory of argumentation frameworks andprocedural models. Then, I will discuss Peczenik'sanalysis of analogy argumentation and try to combineit with the descriptive-normative research ofMacCormick and Summers. Finally, I propose asystematization of the criteria for the evaluation ofanalogy argumentation within the framework of apragma-dialectical notion of an argumentation scheme. (shrink)

Successful accounts of analogy in law have two burdens to discharge. First, they must reflect the fact that the conclusion of an argument by analogy is a normative claim about how to decide a certain case. Second, they must not fail to accord relevance to the fact that the source case was authoritatively decided in a certain way. We argue in the first half of this paper that the common view of the structure of analogical arguments in law cannot overcome (...) these hurdles. In the second half we develop an original account that aims to succeed where others failed. (shrink)

In this contribution two approaches of legal analogy-argumentation will be discussed: the traditional, monological approach and the dialogical approach. This contribution aims at answering the question in how far these approaches may serve as adequate instruments for rational reconstructions of this analogy-argumentation. We will also indicate along which lines the insights resulting from these approaches may be developed further in order to arrive at a more comprehensive and systematic method for a rational reconstruction of argumentation of this sort. We will (...) make use of the insights gained from the pragma-dialectical argumentation theory. (shrink)

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)

The presence of premises expressing comparison is a problem for the Aristotelian theory of the dialectical method, first because there is no general theory of comparison in the Organon and secondly because along with propositions on the opposition and inflexion of the terms, comparative statements seem to fall outside the explicit description which Aristotle gives of possible premises. The purpose of this paper is to offer a synthetic theory of comparisons according to Aristotle’s Topics , in an attempt both to (...) supply the aforementioned absence and to highlight the importance of the second problem. There are three main types of premises on the more, the less and the similar : some comparing the degree of possession of a predicate, others comparing the plausibility of a predication and finally, others expressing an analogy. Once expounded the very marked differences that occur between these three classes of propositions, the paper analyses the various kinds of argumentation based on comparative premises and offers a formalization of its logical laws. The complexity of this theory and the volume of topoi involved in the comparisons show the magnitude of a problem that has not been sufficiently studied. (shrink)

This paper investigates the basis arguments of so-called legal logic and their relation to logic in its standard meaning. There is no doubt that legal arguments belong to logic in the wide sense (sensu largo), but their reduction to schemes of formal logic (logica sensu stricto) is a controversial issue. It can be demonstrated that only some legal arguments fall under explicit rules of formal logic, that is, having a deductive character. Most such reasoning is fallible, and its correctness depends (...) on appealing to extra-logical principles taken from legal norms. For instance, if we say, “If it is permitted more, then it is permitted less” (argumentum a maiori ad minus), we assume that the concepts expressed by the words “more” and “less” are already defined. (shrink)

The author singles out various conceptions of rationality used in practical legal discourse: formal and substantive rationality, instrumental goal‐ and means‐rationality, communicative rationality. Practical rationality is expressed in decisions justified by epistemic and axiological premises according to the rules of justificatory reasoning. Five levels of analysis of this justification are identified. Rules, principles and evaluations are used as justifying arguments and their characteristics determine the dimensions of rationality of decision depending on the features of rules, various conceptions of principles, and (...) kinds of relativisation of evaluations. The dimensions of legal rationality depend mainly on three singled out conceptions of rationality, i.e., formal rationality dealing with the deep structure of justification, instrumentally oriented rationality as content of justifiability, and communicative rationality linked with the pragmatics of human interaction. Legitimacy, according to the presented analysis, appears as a subclass of external justification dealing with axiological premisses in terms of instrumental rationality and/or communicative rationality. (shrink)

The presence of premises expressing comparison is a problem for the Aristotelian theory of the dialectical method, first because there is no general theory of comparison in the Organon and secondly because along with propositions on the opposition and inflexion of the terms, comparative statements seem to fall outside the explicit description which Aristotle gives of possible premises. The purpose of this paper is to offer a synthetic theory of comparisons according to Aristotle’s Topics, in an attempt both to supply (...) the aforementioned absence and to highlight the importance of the second problem. There are three main types of premises on the more, the less and the similar: some comparing the degree of possession of a predicate, others comparing the plausibility of a predication and finally, others expressing an analogy. Once expounded the very marked differences that occur between these three classes of propositions, the paper analyses the various kinds of argumentation based on comparative premises and offers a formalization of its logical laws. The complexity of this theory and the volume of topoi involved in the comparisons show the magnitude of a problem that has not been sufficiently studied. (shrink)