Have you ever read a legal opinion and come across an odd term like the fallacy of denying the antecedent, the fallacy of the undistributed middle, or the fallacy of the illicit process and wondered how you missed that in law school? You’re not alone: every day, lawyers make arguments that fatally trespass the rules of formal logic—without realizing it—because traditional legal education often overlooks imparting the practical wisdom of ancient philosophy as it teaches students how to “think like a lawyer.” In his book, The Force of Logic: Using Formal Logic as a Tool in the Craft of Legal Argument, lawyer and law professor Stephen M. Rice guides you to develop your powers of legal reasoning in a new way, through effective tips and tactics that will forever change the way you argue your cases. Rice contends that formal logic provides tools that help lawyers distinguish good arguments from bad ones and, moreover, that they are simple to learn and use. When you know how to recognize logical fallacies, you will not only strengthen your own arguments, but you will also be able to punch holes in your opponent’s—and that can make the difference between winning and losing. In this book, Rice builds on the theoretical foundation of formal logic by demonstrating logical fallacies through the use of anecdotes, examples, graphical illustrations, and exercises for you to try that are derived from common case documents. It is a hands-on primer that presents a practical approach for understanding and mastering the place of formal logic in the art of legal reasoning. Whether you are a lawyer, a judge, a scholar, or a student, The Force of Logic will inspire you to love legal argument, and appreciate its beauty and complexity in a brand new way.

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.

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.

This book tackles the basics of legal reasoning in twelve chapters, including the principles of classic logic, deductive and inductive reasoning, application of the Socratic method to legal reasoning, and formal and material fallacies.

Rule-applying legal arguments are traditionally treated as a kind of syllogism. Such a treatment overlooks the fact that legal principles and rules are not statements which describe the world, but rather means by which humans impose structure on the world. Legal rules create legal consequences, they do not describe them. This has consequences for the logic of rule- and principle-applying arguments, the most important of which may be that such arguments are defeasible. This book offers an extensive analysis of the role of rules and principles in legal reasoning, which focuses on the close relationship between rules, principles, and reasons. Moreover, it describes a logical theory which assigns a central place to the notion of reasons for and against a conclusion, and which is especially suited to deal with rules and principles.

This book explores relationships between law and legal reasoning, and recent developments in formal logic.