This book identifies 25 argumentation schemes for presumptive reasoning and matches a set of critical questions to each.

Vol. presents a method for critically evaluating relevance in arguments based on case studies & a new relevance theory incorporating techniques of argumentation theory, logic & artificiaI intelligence. For scholars/students in argumentation & rhetoric.

Husak's primary goal is to defend a set of constraints to limit the authority of states to enact and enforce criminal offenses. In addition, Husak situates this endeavor in criminal theory as traditionally construed. This book urges the importance of this topic in the real world, while most Anglo-American legal philosophers have neglected it.

William Baird collection in Social Sciences is the gift of the Estate of William Cameron Baird.

Appeals to emotion—pity, fear, popular sentiment, and _ad hominem_ attacks—are commonly used in argumentation. Instead of dismissing these appeals as fallacious wherever they occur, as many do, Walton urges that each use be judged on its merits. He distinguished three main categories of evaluation. First, is it reasonable, even if not conclusive, as an argument? Second, is it weak and therefore open to critical questioning for argument? And third, is it fallacious? The third category is a strong charge that incurs (...) a critical burden to back it up by citing evidence from the given text and context of dialogue. Walton uses fifty-six case studies to demonstrate that the problem of emotional fallacies is much subtler than has been previously believed. Ranging over commercial advertisements, political debates, union-management negotiations, and ethical disputes, the case studies reveal that these four types of appeals, while based on presumptive reasoning that are tentative and subject to default, are not always or necessarily fallacious types of argumentation. (shrink)

Does criminal liability require an act? -- Motive and criminal liability -- The costs to criminal theory of supposing that intentions are irrelevant to permissibility -- Transferred intent -- The nature and justifiability of nonconsummate offenses -- Strict liability, justice, and proportionality -- The sequential principle of relative culpability -- Willful ignorance, knowledge, and the equal culpability thesis : a study of the significance of the principle of legality -- Rapes without rapists : consent and reasonable mistake -- Mistake of (...) law and culpability -- On the supposed priority of justification to excuse -- Partial defenses -- The "but everybody does that!" defense -- The de minimis "defense" to criminal liability -- Why punish the deserving -- Malum prohibitum and retributivism -- Already punished enough. (shrink)

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. (shrink)

A "slippery slope argument" is a type of argument in which a first step is taken and a series of inextricable consequences follow, ultimately leading to a disastrous outcome. Many textbooks on informal logic and critical thinking treat the slippery slope argument as a fallacy. Walton argues that used correctly in some cases, they can be a reasonable type of argument to shift a burden of proof in a critical discussion, while in other cases they are used incorrectly. Walton identifies (...) and analyzes four types of slippery slope argument. Walton presents guidelines that show how each type of slippery slope argument can be used correctly or incorrectly, using over fifty case studies of argumentation on controversial issues. These include abortion, medical research on human embryos, euthanasia, the decriminalization of marijuana, pornography, and censorship, and banning of American flag burning. (shrink)

This book examines three areas in which abductive reasoning is especially important: medicine, science, and law. The reader is introduced to abduction and shown how it has evolved historically into the framework of conventional wisdom in logic. Discussions draw upon recent techniques used in artificial intelligence, particularly in the areas of multi-agent systems and plan recognition, to develop a dialogue model of explanation. Cases of causal explanations in law are analyzed using abductive reasoning, and all the components are finally brought (...) together to build a new account of abductive reasoning. By clarifying the notion of abduction as a common and significant type of reasoning in everyday argumentation, _Abductive Reasoning_ will be useful to scholars and students in many fields, including argumentation, computing and artificial intelligence, psychology and cognitive science, law, philosophy, linguistics, and speech communication and rhetoric. (shrink)

In redefining logic, philosophers need to go back to the Aristotelian roots of the subject, to expand the boundaries of the subject to include informal logic and to give up false oppositions between informal and formal logic.

_Arguments from Ignorance _explores the situations in which the argument from ignorance functions as a respectable form of reasoning and those in which it is indeed fallacious. Douglas Walton draws on everyday conversations on all kinds of practical matters in which the _argumentum ad ignorantiam _is used quite appropriately to infer conclusions. He also discusses the inappropriate use of this kind of argument, referring to various major case studies, including the Salem witchcraft trials, the McCarthy hearings, and the Alger (...) Hiss case. This book makes an original contribution in the areas of argumentation theory and informal logic, contending that, despite its traditional classification as a fallacy, the argument from ignorance is a genuine, very common, and legitimate type of argumentation with an identifiable structure. But the book is also interdisciplinary in scope, explaining many widely interesting and controversial subjects in artificial intelligence, medical education, philosophy of science, and philosophy of law in a clear way that makes it accessible to a broad range of readers. (shrink)

I assess the thesis that counterfactual asymmetries are explained by an asymmetry of the global entropy at the temporal boundaries of the universe, by developing a method of evaluating counterfactuals that includes, as a background assumption, the low entropy of the early universe. The resulting theory attempts to vindicate the common practice of holding the past mostly fixed under counterfactual supposition while at the same time allowing the counterfactual's antecedent to obtain by a natural physical development. Although the theory has (...) some success in evaluating a wide variety of ordinary counterfactuals, it fails as an explanation of counterfactual asymmetry. (shrink)

This book provides a practical and accessible way of evaluating good and bad arguments used in everyday conversations by applying normative models of dialectical (interactive) argumentation, where two parties reason together in an orderly and cooperative way. Using case studies, the author analyzes correct and incorrect uses of argumentation on controversial issues that engage the reader's interest while illustrating points in a practical way. Walton gives clear explanations of the most common errors and tricky deceptions -- traditionally called "fallacies" -- (...) that can trip up an unwary arguer. (shrink)

This book argues that ignorance of law should usually be a complete excuse from criminal liability. It defends this conclusion by invoking two presumptions: first, the content of criminal law should conform to morality; second, mistakes of fact and mistakes of law should be treated symmetrically.

The basic question of this monograph is: how should we go about judging arguments to be reasonable or unreasonable? Our concern will be with argument in a broad sense, with realistic arguments in natural language. The basic object will be to engage in a normative study of determining what factors, standards, or procedures should be adopted or appealed to in evaluating an argument as "good," "not-so-good," "open to criticism," "fallacious," and so forth. Hence our primary concern will be with the (...) problems of how to criticize an argument, and when a criticism is reasonably justified. (shrink)

It is a longstanding if not altogether coherent tradition of logic and rhetorical studies that an argument can be incorrect or fallacious in virtue of some ...

This volume collects 17 of Douglas Husak's influential essays in criminal law theory. The essays span Husak's original and provocative contributions to the central topics in the field, including the grounds of criminal liability, relative culpability, the role of defences, and the justification of punishment. The volume includes an extended introduction by the author, drawing together the themes of his work, and exploring the goals of criminal theory.

This book is an analysis of the distinctive form of reasoning, called practical reasoning by Aristotle (as opposed to theoretical reasoning), that serves to guide behaviour.

A general outline of a theory of reasoned dialogue is presented as an underlying basis of critical analysis of a text of argument discourse. This theory is applied to the analysis of informal fallacies by showing how textual evidence can be brought to bear in argument reconstruction. Several basic types of dialogue are identified and described, but the persuasive type of dialogue is emphasized as being of key importance to critical thinking theory.

A rational defense of the criminal law must provide a comprehensive theory of culpability. A comprehensive theory of culpability must resolve several difficult issues; in this article I will focus on only one. The general problem arises from the lack of a systematic account of relative culpability. An account of relative culpability would identify and defend a set of considerations to assess whether, why, under what circumstances, and to what extent persons who perform a criminal act with a given culpable (...) state are more or less blameworthy than persons who perform that act with a different culpable state. (shrink)

The aim of this paper is to make it clear how and why begging the question should be seen as a pragmatic fallacy which can only be properly evaluated in a context of dialogue. Included in the paper is a review of the contemporary literature on begging the question that shows the gradual emergence over the past twenty years or so of the dialectical conception of this fallacy. A second aim of the paper is to investigate a number of general (...) problems raised by the pragmatic framework. (shrink)

Arguments from popular opinion have long been regarded with suspicion, and in most logic textbooks the _ad populum _argument is classified as a fallacy. Douglas Walton now asks whether this negative evaluation is always justified, particularly in a democratic system where decisions are based on majority opinion. In this insightful book, Walton maintains that there is a genuine type of argumentation based on commonly accepted opinions and presumptions that should represent a standard of rational decision-making on important issues, especially (...) those of a personal and political nature. He shows how to judge arguments based on appeals to popular opinion in a more balanced way, identifying eleven subtypes of the _ad populum_ argument and providing a pragmatic method to evaluate each of these types. Walton has examined dozens of logic texts and drawn on a wide range of literature to reveal the many uses and misuses of popular opinion. He contrasts the traditional discussion of _ad populum _in Greek rhetoric with recent textbook treatment, then contrasts these contemporary views with his own dialectical perspective in order to clarify often confused appeals to prejudice and appeals to common knowledge. Although appeal to popular opinion has long been a powerful argumentative tactic, this is the first book to systematically describe and evaluate it as a well-defined type of argument with its own special characteristics. It enables us to deal with these often deceptive arguments in a critically balanced way and makes an original contribution to an important strand of rhetoric. (shrink)

This important book was the first serious work of philosophy to address the question: Do adults have a moral right to use drugs for recreational purposes? Many critics of the 'war on drugs' denounce law enforcement as counterproductive and ineffective. Douglas Husak argues that the 'war on drugs' violates the moral rights of adults who want to use drugs for pleasure, and that criminal laws against such use are incompatible with moral rights. This is not a polemical tract but (...) a scrupulously argued work of philosophy that takes full account of all available data concerning drug use in the United States today. The author is careful to describe the properties a recreational drug would have to possess before the state would be justified in prohibiting it. Since criminal laws against the use of recreational drugs are justified neither by the harm users cause to themselves nor by the harm users cause to each other, Professor Husak concludes that such laws are, in almost all cases, unjustified. (shrink)

Liz Jackson is Professor of Education and Head of Department of International Education at the Education University of Hong Kong. Liz served as the President of the Philosophy of Education Society...

In lieu of an abstract, here is a brief excerpt of the content:Philosophy and Rhetoric 34.2 (2001) 93-112 [Access article in PDF] Enthymemes, Common Knowledge, and Plausible Inference Douglas Walton The study of enthymemes has always been regarded as important in logic, critical thinking, and rhetoric, but too often it is the formal or mechanistic aspect of it that has been in the forefront. This investigation will show that there is a kind of plausibilistic script-based reasoning, of a kind (...) that has mainly been studied in artificial intelligence, that should have a much more important role to play in the study of enthymemes. But then curiously, as will also be shown, this plausibilistic type of reasoning was familiar in the ancient world, to the Sophists, as well as to leading philosophers such as Plato and Aristotle. By linking this ancient notion of plausibility to the modern notion used in computer science, this investigation reveals an important basis for the enthymeme that has a type of logical structure in its own right, but also has an informal aspect.An enthymeme, in current usage, is an argument that has one or more premises, or possibly a conclusion, not explicitly stated in the text, but that needs to have these propositions explicitly stated to extract the complete argument from the text. Sometimes enthymemes are described as arguments with "missing premises." That vocabulary is awkward, however, because the nonexplicit statement that needs to be added can be a conclusion, at least in a minority of cases. To make the exposition below smoother, the term nonexplicit assumption will be used to cover either the case of a nonexplicit premise or that of a nonexplicit conclusion. The problem with enthymemes is that if the nonexplicit assumptions in an argument are supposed to be propositions used by the arguer (as opposed to just the propositions needed to make the argument structurally correct, according to some standard), reasonable people can have differences of opinion on what the nonexplicit assumptions are supposed to be. The problem is that filling in the missing parts of enthymemes depends on interpreting the natural language [End Page 93] in which the argument was put forward to try to determine what the speaker meant to say.The solution to the problem comes through the recognition that enthymemes rest not only on formal (structural) criteria, but also on informal criteria. One of the most important of these informal criteria is something often called "common knowledge" (Govier 1992; Freeman 1995). But as shown below in a set of selected case studies of enthymemes, "common knowledge" is not really a kind of knowledge at all. It is really plausibility, or eikos, something well known in the ancient world and often misleadingly translated as "probability." Curiously, Aristotle's original doctrine of the enthymeme was based on this notion of plausibility. This historical fact has often been a source of puzzlement and confusion, and sometimes it has even been taken to indicate a defect or contradiction in Aristotle's treatment of the enthymeme. However, the goal of this investigation is not primarily historical. It is to work out one of the most important required steps toward a solution to the problem of enthymemes. But to do this, it is necessary to come back to the ancient notion of plausible inference. 1. The problem with enthymemes Once you have any formal theory of inference, like syllogistic, for example, you will be confronted by cases of arguments in everyday discourse that meet all the requirements for a structurally correct inference except that some part or parts, usually a premise or a conclusion, is missing. By "missing" is meant that the proposition in question has not been explicitly stated in the text of discourse, even though it may be clear enough that the speaker (writer) was relying on it, or including it, as part of the argument. The classic example is the following inference: All men are mortal; therefore, Socrates is mortal. To evaluate such an argument, surely some account of the "hidden" or "missing" assumption needs to be taken. The problem with enthymemes (Burke 1985; Gough and Tindale 1985; Hitchcock 1985) is that, if given carte... (shrink)

This paper presents a speech act analysis of presumption, using the framework of a dialogue in which two parties reason together. In the speech act of presumption, as opposed to that of assertion, the burden of proof resides not on the proponent to prove, but on the respondent to rebut. Some connections of this account with nonmonotonic reasoning and informal fallacies in argumentation are explored.