Logical Models of Legal Argumentation


Book Description

In the study of forms of legal reasoning, logic and argumentation theory long followed separate tracks. `Legal logicians' tended to focus on a deductive reconstruction of justifying a decision, disregarding the dialectical process leading to the chosen justification. Others instead emphasized the adversarial and discretionary nature of legal reasoning, involving reasonable evaluation of alternative choices, and the use of analogical reasoning. Recently, however, developments in Artificial Intelligence and Law have paved the way for overcoming this separation. Logic has widened its scope to defensible argumentation, and informal accounts of analogy and dialectics have inspired the construction of computer programs. Thus the prospect is emerging of an integrated logical and dialectical account of legal argument, adding to the understanding of legal reasoning, and providing a formal basis for computer tools that assist and mediate legal debates while leaving room for human initiative. This book presents contributions to this development. From a logical point of view it covers topics such as evaluating conflicting arguments, weighing reasons, modelling legal disputes as a dialogue game, the role of the burden of proof, the relation between principles, rules, reasons and facts, and the relation between deductive and nondeductive arguments. Written by leading scholars in the field and building on recent developments in logic and Artificial Intelligence, the chapters provide a state-of-the-art account of research on the logical aspects of legal argument.







Logical Tools for Modelling Legal Argument


Book Description

This book is a revised and extended version of my PhD Thesis 'Logical Tools for Modelling Legal Argument', which I defended on 14 January 1993 at the Free University Amsterdam. The first five chapters of the thesis have remained almost completely unchanged but the other chapters have undergone considerable revision and expansion. Most importantly, I have replaced the formal argument-based system of the old Chapters 6, 7 and 8 with a revised and extended system, whieh I have developed during the last three years in collaboration with Giovanni Sartor. Apart from some technical improvements, the main additions to the old system are the enriehment of its language with a nonprovability operator, and the ability to formalise reasoning about preference criteria. Moreover, the new system has a very intuitive dialectieal form, as opposed to the rather unintuitive fixed-point appearance of the old system. Another important revision is the split of the old Chapter 9 into two new chapters. The old Section 9. 1 on related research has been updated and expanded into a whole chapter, while the rest of the old chapter is now in revised form in Chapter 10. This chapter also contains two new contributions, a detailed discussion of Gordon's Pleadings Game, and a general description of a multi-Iayered overall view on the structure of argu mentation, comprising a logieal, dialectical, procedural and strategie layer. Finally, in the revised conclusion I have paid more attention to the relevance of my investigations for legal philosophy and argumentation theory.




Legal Argumentation and Evidence


Book Description

A leading expert in informal logic, Douglas Walton turns his attention in this new book to how reasoning operates in trials and other legal contexts, with special emphasis on the law of evidence. The new model he develops, drawing on methods of argumentation theory that are gaining wide acceptance in computing fields like artificial intelligence, can be used to identify, analyze, and evaluate specific types of legal argument. In contrast with approaches that rely on deductive and inductive logic and rule out many common types of argument as fallacious, Walton&’s aim is to provide a more expansive view of what can be considered &"reasonable&" in legal argument when it is construed as a dynamic, rule-governed, and goal-directed conversation. This dialogical model gives new meaning to the key notions of relevance and probative weight, with the latter analyzed in terms of pragmatic criteria for what constitutes plausible evidence rather than truth.




Modeling Legal Argument


Book Description

"Modeling Legal Argument "provides a comprehensive treatment of case-based reasoning and a detailed description of a computer program called Hypo, that models the way attorneys argue with cases, real and hypothetical. The program offers significant advantages over "keyword" case retrieval systems in the legal field and demonstrates how to design expert systems that assist the user by presenting reasonable alternative answers on all sides of an issue and by citing case examples to explain their advice.Hypo analyzes problem situations dealing with trade secrets disputes, retrieves relevant legal cases from its database and fashions them into reasonable legal arguments about who should win. The arguments demonstrate the program's ability to reason symbolically with past cases, to draw factual analogies between cases, to cite them in arguments, to distinguish them, and to pose counter-examples and hypotheticals based on past cases."Modeling Legal Argument "discusses the law as a paradigm of case-based argument, introduces Hypo and its adversarial reasoning process, provides an overview of the Hypo program, and gives extended examples of the model's reasoning capabilities. It describes the case knowledge base, a dimensional index, basic mechanisms of case-based reasoning, and offers a theory of case-based argument in Hypo. Ashley evaluates Hypo's performance and takes up adversarial case-based reasoning beyond the law and extensions of the Hypo model.Kevin D. Ashley is a Research Scientist at the Learning Research an Development Center and Assistant Professor of Law at the University of Pittsburgh. "Modeling Legal Argument is "included in the Artificial Intelligence and Legal Reasoning series, edited by L. Thorne McCarty and Edwina L. Rissland.




Artificial Intelligence and Legal Analytics


Book Description

This book describes how text analytics and computational models of legal reasoning will improve legal IR and let computers help humans solve legal problems.




Fundamentals of Legal Argumentation


Book Description

Legal argumentation is a distinctively multidisciplinary field of inquiry. It draws its data, assumptions and methods from disciplines such as legal theory, legal philosophy, logic, argumentation theory, rhetoric, linguistics, literary theory, philosophy, sociology, and artificial intelligence. This presents the growing group of interested scholars and students with a problem of access, since, even for those active in the field, it is not common to have acquired a familiarity with relevant aspects of each discipline that enters into this multidisciplinary matrix. Fundamentals of Legal Argumentation offers its readers a unique and comprehensive survey of the various theoretical influences which have informed the study of legal argumentation. It discusses salient backgrounds to this field as well as all major approaches and trends in the contemporary research. It surveys relevant theoretical factors both from various continental law traditions and common law countries.




Argument Types and Fallacies in Legal Argumentation


Book Description

This book provides theoretical tools for evaluating the soundness of arguments in the context of legal argumentation. It deals with a number of general argument types and their particular use in legal argumentation. It provides detailed analyses of argument from authority, argument ad hominem, argument from ignorance, slippery slope argument and other general argument types. Each of these argument types can be used to construct arguments that are sound as well as arguments that are unsound. To evaluate an argument correctly one must be able to distinguish the sound instances of a certain argument type from its unsound instances. This book promotes the development of theoretical tools for this task.




Legal Argumentation Theory: Cross-Disciplinary Perspectives


Book Description

This book offers its readers an overview of recent developments in the theory of legal argumentation written by representatives from various disciplines, including argumentation theory, philosophy of law, logic and artificial intelligence. It presents an overview of contributions representative of different academic and legal cultures, and different continents and countries. The book contains contributions on strategic maneuvering, argumentum ad absurdum, argumentum ad hominem, consequentialist argumentation, weighing and balancing, the relation between legal argumentation and truth, the distinction between the context of discovery and context of justification, and the role of constitutive and regulative rules in legal argumentation. It is based on a selection of papers that were presented in the special workshop on Legal Argumentation organized at the 25th IVR World Congress for Philosophy of Law and Social Philosophy held 15-20 August 2011 in Frankfurt, Germany.




Legal Reasoning and Legal Theory


Book Description

What makes an argument in a law case good or bad? Can legal decisions be justified by purely rational argument or are they ultimately determined by more subjective influences? These questions are central to the study of jurisprudence, and are thoroughly and critically examined in Legal Reasoning and Legal Theory, now with a new and up-to-date foreword. Its clarity of explanation and argument make this classic legal text readily accessible to lawyers, philosophers, and any general reader interested in legal processes, human reasoning, or practical logic.