There is an increasing need for norms to be embedded in technology as the widespread deployment of applications such as autonomous driving, warfare and big data analysis for crime fighting and counter-terrorism becomes ever closer. Current approaches to norms in multi-agent systems tend either to simply make prohibited actions unavailable, or to provide a set of rules which the agent is obliged to follow, either as part of its design or to avoid sanctions and punishments. In this paper we argue (...) for the position that agents should be equipped with the ability to reason about a system’s norms, by reasoning about the social and moral values that norms are designed to serve; that is, perform the sort of moral reasoning we expect of humans. In particular we highlight the need for such reasoning when circumstances are such that the rules should arguably be broken, so that the reasoning can guide agents in deciding whether to comply with the norms and, if violation is desirable, how best to violate them. One approach to enabling this is to make use of an argumentation scheme based on values and designed for practical reasoning: arguments for and against actions are generated using this scheme and agents choose between actions based on their preferences over these values. Moral reasoning then requires that agents have an acceptable set of values and an acceptable ordering on their values. We first discuss how this approach can be used to think about and justify norms in general, and then discuss how this reasoning can be used to think about when norms should be violated, and the form this violation should take. We illustrate how value based reasoning can be used to decide when and how to violate a norm using a road traffic example. We also briefly consider what makes an ordering on values acceptable, and how such an ordering might be determined. (shrink)

In some cases of disagreement, particularly in ethics and law, it is impossible to provide any conclusive demonstration. The role of argument in such cases is to persuade rather than to prove. Drawing on ideas ofPerelrnan, we argue that persuasion in such cases relies on a recognition that the strength of such arguments will vary according to their audience, and depends on the comparative weight that the audiences gives to the social values that it advances. To model this, we introduce (...) the notion of Value-based Argumentation Frameworks (VAFs), an extension of Argumentation Frameworks as originally introduced by Dung. We then describe a dialogue game based on VAFs, designed to model persuasive argumentation, which we illustrate with a widely discussed ethical problem. (shrink)

This paper approaches legal argumentation from a rhetorical perspective. It discusses the nature of the audiences that are targeted by judges in the legal process. Judicial opinions reach diverse groups of people with very different attitudes and expectations: other judges, lawyers, litigants, concerned citizens, etc. One important way in which these groups differ is that some of them are more likely to be persuaded by legalistic, precedent or statute-based arguments, while others expect judges to decide on grounds of justice or (...) equity. So, judges face the challenge of determining whether they should select particular groups for special attention, or whether they have alternative rhetorical means to approach the problem of audience diversity. One strategy that is likely to be recommended by rhetorical scholars is that judges should not try to accommodate the various preferences of their actual readership, but that they should rather invoke an idealized audience or some version of Chaïm Perelman’s universal audience. However, the paper tries to show that the universal audience is of limited value for a discussion about how judges ought to proceed in the face of audience diversity. In particular, the idea of a universal audience does not help judges to make the choice between a legalistic or an equity-based approach to legal decision-making. By showing that this is so, the paper also raises doubts about the common thought that to invoke the universal audience in law is to appeal to natural law. (shrink)

Law can be characterised as a highly specialized tool with strong social impact requiring social legitimization and acceptance. Law is also specific, abstract world. World that needs words to exist. To understand law and to share its content it is important to focus on narratives related to it. The article deals with the importance of narration in law as the consequence of discursive peculiarity of law and its dependence on the acceptance of societies. Law is culturally conditioned, and by means (...) of narrative can combine the expectations of society concerning legitimation with legal rationality. The law cannot function exclusively as an abstract and formal structure nor an administrative apparatus, with own ways of legitimization or justification. Through social acceptance law gains its real form, but at the same time it is subordinated to cultural patterns. Changes in narratives change the law and then the real world. The article shows possible ways of analysis of narratives, narrative strategies and forms that are present in law. (shrink)

According to Perelman (Rhétoriques, Presses Universitaires de Bruxelles, 1989: 80), a pseudo-argument is an argument that is supposed to be convincing from a given audience viewpoint, while it is not from another audience viewpoint. Such a claim raises the traditional problem of the boundaries between the well known “convince versus persuade” dichotomy. This paper aims at investigating it from a contemporary rhetorical and argumentative perspective which will take into account the fictional dimension of persuasion. In this perspective, it will be (...) claimed that the notion of an “as if” argument better fits to some rhetorical phenomena. (shrink)

In this paper I argue that to explain and resolve some kinds of disagreement we need to go beyond what logic alone can provide. In particular, following Perelman, I argue that we need to consider how arguments are ascribed different strengths by different audiences, according to how accepting these arguments promotes values favoured by the audience to which they are addressed. I show how we can extend the standard framework for modelling argumentation systems to allow different audiences to be represented. (...) I also show how this formalism can explain how some disputes can be resolved while in others the parties can only agree to differ. I illustrate this by consideration of a legal example. Finally, I make some suggestions as to where these values come from, and how they can be used to explain differences across jurisdictions, and changes in views over time. (shrink)

This paper is an introduction to a virtual special issue of AI and Law exploring the legacy of the influential HYPO system of Rissland and Ashley. The papers included are: Arguments and cases: An inevitable intertwining, BankXX: Supporting legal arguments through heuristic retrieval, Modelling reasoning with precedents in a formal dialogue Game, A note on dimensions and factors, An empirical investigation of reasoning with legal cases through theory construction and application, Automatically classifying case texts and predicting outcomes, A factor-based definition (...) of precedential constraint and An improved factor based approach to precedential constraint. After describing HYPO, in this introduction to the special issue I look at various aspects of its influence on AI and Law: the developments led by Rissland at Amherst; the developments led by Ashley in Pittsburgh; the expression of these ideas in terms of rule based systems, and their subsequent formalisation; value based theories, which were inspired by a critique of HYPO; and contemporary approaches which revive the idea of dimensions. (shrink)

The article develops and justifies, on the basis of the epistemological argumentation theory, two central pieces of the theory of evaluative argumentation interpretation: 1. criteria for recognizing argument types and 2. rules for adding reasons to create ideal arguments. Ad 1: The criteria for identifying argument types are a selection of essential elements from the definitions of the respective argument types. Ad 2: After presenting the general principles for adding reasons (benevolence, authenticity, immanence, optimization), heuristics are proposed for finding missing (...) reasons, for deductive arguments, e.g., semantic tableaux are suggested. (shrink)

The concept of conductive argument weight was developed by Carl Wellman and later by Trudy Govier. This concept has received renewed attention recently from another informal logician, Robert C. Pinto. Argument weight has also been addressed in recent years by theorists in AI & Law. I argue from a non-technical perspective that some aspects of AI & Law’s approach to argument weight can be usefully applied to the issues addressed by Pinto. I also relate some of these issues to the (...) work of argument theorist Harald Wohlrapp. (shrink)

Topical Themes in Argumentation Theory brings together twenty exploratory studies on important subjects of research in contemporary argumentation theory. The essays are based on papers that were presented at the 7th Conference of the International Society for the Study of Argumentation in Amsterdam in June 2010. They give an impression of the nature and the variety of the kind of research that has recently been carried out in the study of argumentation. The volume starts with three essays that provide stimulating (...) theoretical perspectives on argumentation. Subsequently, some views are explained on the intriguing topics of ‘dissensus’ and ‘deep disagreement’. After a discussion of three different approaches to the treatment of types of argumentation some classical themes from antique argumentation theory are revisited. The new research area of visual argumentation is explored in the next part. The volume concludes with three reports of experimental studies concerning argumentative discourse. The volume starts with three essays that provide stimulating theoretical perspectives on argumentation. Subsequently, some views are explained on the intriguing topics of ‘dissensus’ and ‘deep disagreement’. After a discussion of three different approaches to the treatment of types of argumentation some classical themes from antique argumentation theory are revisited. The new research area of visual argumentation is explored in the next part. The volume concludes with three reports of experimental studies concerning argumentative discourse. The volume starts with three essays that provide stimulating theoretical perspectives on argumentation. Subsequently, some views are explained on the intriguing topics of ‘dissensus’ and ‘deep disagreement’. After a discussion of three different approaches to the treatment of types of argumentation some classical themes from antique argumentation theory are revisited. The new research area of visual argumentation is explored in the next part. The volume concludes with three reports of experimental studies concerning argumentative discourse. (shrink)