Reasoning may be defined as a deliberate effort to coordinate inferences so as to reach justifiable conclusions. Thus defined, reasoning includes collaborative as well as individual forms of cognitive action. The purpose of the present study was to demonstrate a circumstance in which collaborative reasoning is qualitatively superior to individual reasoning. The selection task, a well known logical hypothesis-testing problem, was presented to 143 college undergraduates-32 individuals and 20 groups of 5 or 6 interacting peers. The correct (falsification) response pattern (...) was selected by only 9% of the individuals but by 75% of the groups. The superior performance of the groups was due to collaborative reasoning rather than to imitation or peer pressure. Groups typically co-constructed a structure of arguments qualitatively more sophisticated than that generated by most individuals. The results support Piagetian and Habermasian views of peer interaction as a locus of rational social processes. (shrink)

There are obvious benefits to be gained from the study of logic: heightened ability to express ideas clearly and concisely, increased skill in defining one's terms, enlarged capacity to formulate arguments rigorously and to analyze them critically. But the greatest benefit, in my judgment, is the recognition that reason can be applied in every aspect of human affairs.

Causality offers the first comprehensive coverage of causal analysis in many sciences, including recent advances using graphical methods. Pearl presents a unified account of the probabilistic, manipulative, counterfactual and structural approaches to causation, and devises simple mathematical tools for analyzing the relationships between causal connections, statistical associations, actions and observations. The book will open the way for including causal analysis in the standard curriculum of statistics, artificial intelligence, business, epidemiology, social science and economics.

This important book provides a new unifying methodology for logic. It replaces the traditional view of logic as manipulating sets of formulas with the notion of structured families of labelled formulas with algebraic structures. This approach has far reaching consequences for the methodology of logics and their semantics, and the book studies the main features of such systems along with their applications. It will interest logicians, computer scientists, philosophers and linguists.

Scientific reasoning is—and ought to be—conducted in accordance with the axioms of probability. This Bayesian view—so called because of the central role it accords to a theorem first proved by Thomas Bayes in the late eighteenth ...

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 offers a new theory of begging the question as an informal fallacy, within a pragmatic framework of reasoned dialogue as a normative theory of critical argumentation. The fallacy of begging the question is analyzed as a systematic tactic to evade fulfillment of a legitimate burden of proof by the proponent of an argument. The technique uses a circular structure of argument to block the further progress of dialogue and, in particular, the capability of the respondent to ask legitimate (...) critical questions in reply to the argument. Walton analyzes the concept of burden of proof in argument, and provides chapters on the use of argument diagramming as a technique of argument reconstruction. This powerful method of argument analysis developed therein is then applied to more than 100 case studies of circular argumentation where the charge of begging the question is or has been thought to be an appropriate criticism. Throughout this work, Walton throws light on the relationship between the problem of circular reasoning and broader issues in the critical analysis of argumentation. Ground-breaking use is made of the pragmatic theory of argument as interactive dialogue. Rules for several kinds of dialogue framework provide standards of good reasoning to validate or to refute the criticism that a particular argument begs the question. This book is directed to students and professionals in the fields of speech communication, philosophy, linguistics, logic, dispute mediation, and education. (shrink)

The question addressed in this paper is how the degree of justification of a belief is determined. A conclusion may be supported by several different arguments, the arguments typically being defeasible, and there may also be arguments of varying strengths for defeaters for some of the supporting arguments. What is sought is a way of computing the “on sum” degree of justification of a conclusion in terms of the degrees of justification of all relevant premises and the strengths of all (...) relevant reasons. (shrink)

This paper disputes the widely held view that one cannot establish the reliability of a belief-forming process with the use of belief's that are obtained by that very process since such self-dependent justification is circular. Harold Brown ([1993]) argued in this journal that some cases of self-dependent justification are legitimate despite their circularity. I argue instead that under appropriate construal many cases of self-dependent justification are not truly circular but are instances of ordinary Bayesian confirmation, and hence they can raise (...) the probability of the hypothesis as legitimately as any such confirmation does. I shall argue in particular that despite its dependence on perception we can use naturalized epistemology to confirm the reliability of a perceptual process without circularity. (shrink)

In Minimal Rationality, Christopher Cherniak boldly challenges the myth of Man the the Rational Animal and the central role that the "perfectly rational...

The New Rhetoric is founded on the idea that since “argumentation aims at securing the adherence of those to whom it is addressed, it is, in its entirety, relative to the audience to be influenced,” says Chaïm Perelman and L. Olbrechts-Tyteca, and they rely, in particular, for their theory of argumentation on the twin concepts of universal and particular audiences: while every argument is directed to a specific individual or group, the orator decides what information and what approaches will achieve (...) the greatest adherence according to an ideal audience. This ideal, Perelman explains, can be embodied, for example, "in God, in all reasonable and competent men, in the man deliberating or in an elite.” Like particular audiences, then, the universal audience is never fixed or absolute but depends on the orator, the content and goals of the argument, and the particular audience to whom the argument is addressed. These considerations determine what information constitutes "facts" and "reasonableness" and thus help to determine the universal audience that, in turn, shapes the orator's approach. /// The adherence of an audience is also determined by the orator's use of values, a further key concept of the New Rhetoric. Perelman's treatment of value and his view of epideictic rhetoric sets his approach apart from that of the ancients and of Aristotle in particular. Aristotle's division of rhetoric into three genres–forensic, deliberative, and epideictic–is largely motivated by the judgments required for each: forensic or legal arguments require verdicts on past action, deliberative or political rhetoric seeks judgment on future action, and epideictic or ceremonial rhetoric concerns values associated with praise or blame and seeks no specific decisions. For Aristotle, the epideictic genre was of limited importance in the civic realm since it did not concern facts or policies. Perelman, in contrast, believes not only that epideictic rhetoric warrants more attention, but that the values normally limited to that genre are in fact central to all argumentation. "Epideictic oratory," Perelman argues, "has significant and important argumentation for strengthening the disposition toward action by increasing adherence to the values it lauds.” These values are central to the persuasiveness of arguments in all rhetorical genres since the orator always attempts to "establish a sense of communion centered around particular values recognized by the audience.”. (shrink)

This is an introductory guidebook to the basic principles of how to construct good arguments and how to criticeze bad ones. It is non-technical in its approach and is based on 150 key examples, each discussed and evaluated in clear, illustrative detail. Professor Walton, a leading authority in the field of informal logic, explains how errors, fallacies, and other key failures of argument occur. He shows how correct uses of argument are based on sound strategies for reasoned persuasion and critical (...) responses. Among the many subjects covered are: forms of valid argument, relevance, appeals to emotion, personal attack, uses and abuses of expert opinion, problems in deploying statistics, loading terms, equivocation, arguments from analogy, and techniques of posing, replying to, and criticizing questions. The book will be ideally suited to courses in informal logic and in the introduction to philosophy. It will also prove valuable to studetns of pragmatics, rhetoric, and speech communication. (shrink)

First published in 2000. Routledge is an imprint of Taylor & Francis, an informa company.

_Critical Thinking_ is a much-needed guide to thinking skills and above all to thinking critically for oneself. Through clear discussion, students learn the skills required to tell a good argument from a bad one. Key features include: *jargon-free discussion of key concepts in argumentation *how to avoid confusions surrounding words such as 'truth', 'knowledge' and 'opinion' *how to identify and evaluate the most common types of argument *how to spot fallacies in arguments and tell good reasoning from bad *topical examples (...) from politics, sport, medicine, music *chapter summaries, glossary and exercises _Critical Thinking_ is essential reading for anyone, student or professional, seeking to improve their reasoning and arguing skills. (shrink)

Although fallacies have been common since Aristotle, until recently little attention has been devoted to identifying and defining them. Furthermore, the concept of fallacy itself has lacked a sufficiently clear meaning to make it a useful tool for evaluating arguments. Douglas Walton takes a new analytical look at the concept of fallacy and presents an up-to-date analysis of its usefulness for argumentation studies. Walton uses case studies illustrating familiar arguments and tricky deceptions in everyday conversation where the charge of fallaciousness (...) is at issue. The numerous case studies show in concrete terms many practical aspects of how to use textual evidence to identify and analyze fallacies and to evaluate arguments as fallacious. Walton looks at how an argument is used in the context of conversation. He defines a fallacy as a conversational move, or sequence of moves, that is supposed to be an argument that contributes to the purpose of the conversation but in reality interferes with it. The view is a pragmatic one, based on the assumption that when people argue, they do so in a context of dialogue, a conventionalized normative framework that is goal-directed. Such a contextual framework is shown to be crucial in determining whether an argument has been used correctly. Walton also shows how examples of fallacies given in the logic textbooks characteristically turn out to be variants of reasonable, even if defeasible or questionable arguments, based on presumptive reasoning. This is the essence of the evaluation problem. A key thesis of the book, which must not be taken for granted as previous textbooks have so often done, is that you can spot a fallacy from how it was used in a context of dialogue. This is an innovative and even, as Walton notes, "a radical and controversial" theory of fallacy. (shrink)

_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)

My One Fallacy theory says there is only one fallacy: equivocation, or playing on an ambiguity. In this paper I explain how this theory arose from rnetaphilosophical concerns. And I contrast this theory with purely logical, dialectical, and psychological notions of fallacy.

David Miller elegantly and provocatively reformulates critical rationalism—the revolutionary approach to epistemology advocated by Karl Popper—by answering its most important critics. He argues for an approach to rationality freed from the debilitating authoritarian dependence on reasons and justification. "Miller presents a particularly useful and stimulating account of critical rationalism. His work is both interesting and controversial... of interest to anyone with concerns in epistemology or the philosophy of science." —Canadian Philosophical Reviews.

Slippery slope arguments are commonly thought to be fallacious. But is there a single fallacy which they all commit? A study of applied logic texts reveals competing diagnoses of the supposed error, and several recent authors take slippery slope arguments seriously. Clearly, there is room for comment. I shall give evidence of divergence on the question of what sort of argument constitutes a slippery slope, distinguish four different types of argument which have all been deemed to be slippery slopes, and (...) contend that two of these types need involve no logical error.We find in textbook accounts three quite differently oriented treatments of slippery slope: conceptual — relating to vagueness and the ancient sorites paradox; precedential — relating to the need to treat similar cases consistently; and causal — relating to the avoidance of actions which will, or would be likely to, set off a series of undersirable events. (shrink)

Classic analysis of the subject and the development of personal probability; one of the greatest controversies in modern statistcal thought.

The strength of a slippery slope argument is a matter of some dispute. Some see it as a reasonable argument pointing out what probably or inevitably follows from adopting some practice, others see it as essentially a fallacious argument. However, there seems to be a tendency emerging to say that in many cases, the argument is not actually fallacious, although it may be unsubstantiated. I shall not try to settle this general discussion, but merely seek to assess the strength of (...) the slippery slope argument applied to human gene therapy. The structure of my argument will be the following. First, I shall distinguish between three different versions of the slippery slope argument; two logical versions and an empirical one. Next, I will address human gene therapy in terms of each of the three versions, partly relying on slippery slope arguments against this practice that have already surfaced in the literature. I shall argue that neither version pulls through. The logical versions fail primarily because relevant distinctions can be made between different uses of gene therapy, contrary to what the proponents of the arguments claim. The empirical version fails because there seems to be no evidence supporting the claim that we shall in fact slide down the slope if we engage in gene therapy, and because if we accepted the conclusion that we should not allow gene therapy on the basis of the empirical argument, we should have to make very far-reaching and undesirable modifications in health care in general, in order to be consistent. Or at least so I shall argue. (shrink)

I argue in a non-reductive sense for a plausible epistemic principle, which can (1) theoretically and instrumentally unify or systematize all fallacies, and (2) provide a justification for using such a principle for characterizing an erroneous argument as a fallacy. This plausible epistemic principle involves the idea of an error in the method of justification, which results in a failure to provide relevant evidence to satisfy certain standards of adequate proof. Thus, all fallacies are systematically disguised failures to provide substantive (...) proof: a failure in the attempt to persuade rationally, as opposed to emotionally or rhetorically. I argue that the epistemic idea of begging the question is essential to this idea of a fallacy as an inadequate proof. (shrink)

This is an introductory guide to the basic principles of constructing good arguments and criticizing bad ones. It is nontechnical in its approach, and is based on 150 key examples, each discussed and evaluated in clear, illustrative detail. The author explains how errors, fallacies, and other key failures of argument occur. He shows how correct uses of argument are based on sound argument strategies for reasoned persuasion and critical questions for responding. Among the many subjects covered are: techniques of posing, (...) replying to, and criticizing questions, forms of valid argument, relevance, appeals to emotion, personal attack, uses and abuses of expert opinion, problems in deploying statistics, loaded terms, equivocation, and arguments from analogy. (shrink)

The thesis of this paper is that philosophers are often too hasty in rejecting justifications because the argument that yields the justification is circular. Circularity is distinguished from vicious circularity and several examples are examined in which a proposed justification is circular in a precise sense, but not viciously circular. These include an observational procedure which could yield a velocity in excess of the velocity of light even though the impossibility of such velocities is assumed at a key step in (...) analyzing the data, and an argument that uses a specific argument form to show that that form is invalid. (shrink)