The public must make assessments of a range of health-related issues. However, these assessments require scientific know-ledge which is often lacking or ineffectively utilized by the public. Lay people must use whatever cognitive resources are at their disposal to come to judgement on these issues. It will be contended that a group of arguments—so-called informal fallacies—are a valuable cognitive resource in this regard. These arguments serve as cognitive heuristics which facilitate reasoning when knowledge is limited or beyond the (...) grasp of reasoners. The results of an investigation into the use of these arguments by the public are reported. (shrink)

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)

Populism is on the rise, especially in Western Europe. While it is often assumed that populist actors have a tendency for fallacious reasoning, this has not been systematically investigated. We analyze the use of informal fallacies by right-wing populist politicians and their representation in the media during election campaigns. We conduct a quantitative content analysis of press releases of right-wing populist parties and news articles in print media during the most recent elections in the United Kingdom and Switzerland (...) in 2015. The results show that fallacies are used in more than a third of all analyzed texts and overwhelmingly co-occur with populist key messages. Moreover, fallacies occur more often in populist parties’ press releases than in news articles and are more common in Switzerland compared to the United Kingdom. This study confirms the argument that populist actors use fallacies in combination with populist claims. (shrink)

This essay proposes and defends a general thesis concerning the nature of fallacies of reasoning. These in distinctive ways are all said to be deductively invalid. More importantly, the most accurate, complete and charitable reconstructions of these species and specimens of the informal fallacies are instructive with respect to the individual character of each distinct informal fallacy. Reconstructions of the fallacies as deductive invalidities are possible in every case, if deductivism is true, which means that (...) in every case they should be formalizable in an expressively comprehensive formal symbolic deductive logic. The general thesis is illustrated by a detailed examination of Walter Burleigh's paradox in his c. 1323 work, De Puritate Artis Logicae Tractatus Longior (Longer Treatise on the Purity of Logic), as a challenge to the deductive validity of hypothetical syllogism. The paradox has the form, ‹If I call you a swine, then I call you an animal; if I call you an animal, then I speak truly; therefore, if I call you a swine, then I speak truly'. Several solutions to the problem are considered, and the inference is exposed as an instance of the common deductive fallacy of equivocation. (shrink)

This article argues that theories which regard the mind as merely a form of information processing are guilty of a fallacious conflation of the informational contents of consciousness with consciousness itself, with the consciousness of those contents. Such theories lie behind the thought that a consciousness could be transferred or uploaded onto a substrate other than the brain it initially occurred in. It is argued here that the ontology of information is that of a formal structure that can be instantiated (...) in physical reality innumerable times, whereas the ontology of consciousness is that of an irreducibly singular subjective experience of being alive. (shrink)

Richard Double takes us through James' defence of belief in God, exposing a few fallacies along the way.

An infonnal fallacy is a reasoning error with three features: the reasoning employs an implicit cogent pattern; the fallacy results from one or more false premises; there is culpable ignorance or deception associated with the falsity of the premises. A reconstruction and analysis of the cogent reasoning patterns in fourteen standard infonnal fallacy types plus several variations are given. Defense of the CMR account covers: a general failure to apply the principle of charity in informal fallacy contexts; empirical evidence (...) for it; how it explains Walton's point that there are both fallacious and non-fallacious instances of fallacy types; how it avoids most "relevance" problems, pennits clearer taxonomizing, and promises pedagogical advantages; how it solves a "demarcation problem.". (shrink)

This paper argues that some traditional fallacies should be considered as reasonable arguments when used as part of a properly conducted dialog. It is shown that argumentation schemes, formal dialog models, and profiles of dialog are useful tools for studying properties of defeasible reasoning and fallacies. It is explained how defeasible reasoning of the most common sort can deteriorate into fallacious argumentation in some instances. Conditions are formulated that can be used as normative tools to judge whether a (...) given defeasible argument is fallacious or not. It is shown that three leading violations of proper dialog standards for defeasible reasoning necessary to see how fallacies work are: (a) improper failure to retract a commitment, (b) failure of openness to defeat, and (c) illicit reversal of burden of proof. (shrink)

The following article evaluates two common arguments for preterist interpretations of Mark 13:24-27, collectively dubbed the ‘time-text’ argument. These two arguments support symbolic and/or historicised interpretations. Our thesis is that the first argument is unsound and the second commits the informal fallacy of false dilemma. Owing to these problems, the arguments and preterist interpretations should be rejected in favour of more plausible futurist interpretations.

A concise, easy-to-read introduction to informal logic, "With Good Reason" offers both comprehensive coverage of informal fallacies and an abundance of engaging examples of both well-conceived and faulty arguments. A long-time favorite of both students and instructors, the text continues in its sixth edition to provide an abundance of exercises that help students identify, correct, and avoid common errors in argumentation.

The author designed the Reasoning Analysis Test to provide empirical support for the CRM analysis of informal fallacies. While informal, the results provide presumptive evidence that those committing informal fallacies may tacitly reason as predicted by CRM. Davis has argued persuasively that Gricean theory has not lived up to expectations, In light of his critique, the CRM analyses of Begging the Question and Equivocation are amended. Johnson has provided standards for judging any theory of (...) class='Hi'>informal fallacies. It is argued that CRM survives the Standard Critique and sufficiently meets Johnson's other criteria. (shrink)

lt is now commonplace in fallacy inquiry for many of the traditional informal fallacies to be viewed as reasonable or nonfallacious modes of argument. Central to this evaluative shift has been the attempt to examine traditional fallacies within their wider contexts of use. However, this pragmatic turn in fallacy evaluation is still in its infancy. The true potential of a contextual approach in the evaluation of the fallacies is yet to be explored. I examine how, in (...) the context of scientific inquiry, certain traditional fallacies function by conferring epistemic gains upon inquiry. Specifically, I argue that these fallacies facilitate the progression of inquiry, particularly in the initial stages ofinquiry when the epistemic context is one of uncertainty. The conception of these fallacies that emerges is that of heuristics of reasoning in contexts of epistemic uncertainty. (shrink)

In critical thinking courses, informal fallacies are often best taught through using myriad examples that illustrate the subtle differences between the different fallacies. However, since a heavy reliance can become tedious for students and instructors, one challenge that teaching a critical thinking course involves is striking an appropriate balance between presenting too many and too few examples. This paper presents a way to introduce informal fallacies through an acted-out dialogue, while reserving more traditional examples for (...) homework or in-class discussion. (shrink)

This article outlines criteria for the evaluation of the argumentum ad hominem (argument against the person, or personal attack in argument) that is traditionally a part of the curriculum in informal logic. The argument is shown to be a kind of criticism which works by shifting the burden of proof in dialogue through citing a pragmatic inconsistency in an arguer's position. Several specific cases of ad hominem argumentation which pose interesting problems in analyzing this type of criticism are studied.

Bayesian reasoning has been applied formally to statistical inference, machine learning and analysing scientific method. Here I apply it informally to more common forms of inference, namely natural language arguments. I analyse a variety of traditional fallacies, deductive, inductive and causal, and find more merit in them than is generally acknowledged. Bayesian principles provide a framework for understanding ordinary arguments which is well worth developing.

The paper argues that the two best known formal logical fallacies, namely denying the antecedent (DA) and affirming the consequent (AC) are not just basic and simple errors, which prove human irrationality, but rather informational shortcuts, which may provide a quick and dirty way of extracting useful information from the environment. DA and AC are shown to be degraded versions of Bayes’ theorem, once this is stripped of some of its probabilities. The less the probabilities count, the closer these (...) fallacies become to a reasoning that is not only informationally useful but also logically valid. (shrink)

In this paper, I argue that informational semantics, the most well-known and worked-out naturalistic account of intentional content, conflicts with a fundamental psychological principle about the conditions of belief-formation. Since this principle is an important premise in the argument for informational semantics, the upshot is that the view is self-contradictory??indeed, it turns out to be guilty of a sophisticated version of the fallacy famously committed by Euthyphro in the eponymous Platonic dialogue. Criticisms of naturalistic accounts of content typically proceed piecemeal (...) by narrowly constructed counterexamples, but I argue that the current result is more robust. It affects a broad family of accounts, and provokes a wider doubt about the possibility of successful execution of the naturalistic project. (shrink)

The informal fallacies can be conceived as enthymemes that are formally valid. But, then, what accounts for our sense of their fallaciousness? I explain this in terms of the notion of a warrant.

Fallacies are things people commit, and when they commit them they do something wrong. What kind of activities are people engaged in when they commit fallacies, and in what way are they doing something wrong? Many different things are called fallacies. The diversity of the use of the concept of a fallacy suggests that we are dealing with a family of cases not related by a common essence. However, we suggest a simple account of the nature of (...) fallacies which encompasses them all, viz., the term “fallacy” is our most general term for criticizing any general procedure used for the fixation of beliefs that has an unacceptably high tendency to generate false or unfounded beliefs, relative to that method of fixing beliefs. Very different sorts of things called fallacies are examined in the light of this account, e.g., denying the antecedent, circular arguments, so-called informal fallacies, and propositions said to be fallacies. We do not provide a theory of fallacies. Still, on our account pretty much all of those things that have been called fallacies are fallacies, and they have been called fallacies for pretty much the same reasons. (shrink)

This is a systematic and concise introduction to more than forty fallacies, from anthropomorphism and argumentum ad baculum, to reductionism and the slippery slope argument. With helpful definitions, relevant examples, and thought-provoking exercises, the author guides the reader through the realms of fallacious reasoning and deceptive rhetoric.

This paper offers a solution to the problem of understanding how a fallacious argument can be deceptive by “seeming to be valid”, or (better) appearing to be a better argument of its kind than it really is. The explanation of how fallacies are deceptive is based on heuristics and paraschemes. Heuristics are fast and frugal shortcuts to a solution to a problem that sometimes jump to a conclusion that is not justified. In fallacious instances, according to the theory proposed, (...) this jump overlooks prerequisites of the defeasible argumentation scheme for the type of argument in question. Three informal fallacies, argumentum ad verecundiam , argumentum ad ignorantiam and fear appeal argument, are used to illustrate and explain the theory. (shrink)

We examine in detail three classic reasoning fallacies, that is, supposedly ``incorrect'' forms of argument. These are the so-called argumentam ad ignorantiam, the circular argument or petitio principii, and the slippery slope argument. In each case, the argument type is shown to match structurally arguments which are widely accepted. This suggests that it is not the form of the arguments as such that is problematic but rather something about the content of those examples with which they are typically justified. (...) This leads to a Bayesian reanalysis of these classic argument forms and a reformulation of the conditions under which they do or do not constitute legitimate forms of argumentation. (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)

Our article identifies and describes the metaphoric fallacy to a deductive inference (MFDI) that is an example of incorrect reasoning along the lines of the false analogy fallacy. The MFDI proceeds from informal semantical (metaphorical) claims to a supposedly formally deductive and necessary inference. We charge that such an inference is invalid. We provide three examples of the MFDI to demonstrate the structure of this invalid form of reasoning. Our goal is to contribute to the set of known (...) class='Hi'>informal fallacies. (shrink)

Fallacies of relevance, a major category of informal fallacies, include two that could be called pure fallacies of relevance-the wrong conclusion fallacy and the red herring digression, diversion) fallacy. The problem is how to classify examples of these fallacies so that they clearly fall into the one category or the other, on some rational system of classification. In this paper, the argument diagramming software system, Araucaria. is used to analyze the argumentation in some selected textbook (...) examples of pure fallacies of relevance. A system of classification of these fallacies is proposed, and criteria for determining whether an example should be classified as wrong conclusion or red herring are formulated. A key difference cited is that in a case where the red herring fallacy has been committed, even if the argument may go to a wrong conclusion, there is evidence of the use ofa deceptive tactic of diversion. Textual evidence must indicate that the arguer deliberately interjects a distracting controversy to lead the respondent away from the real issue to be disputed. (shrink)

We have noticed a pattern of arguments that exhibit a type of irrationality or a particular informal logical fallacy that is not fully captured by any existing fallacy. This fallacy can be explored through three examples where one misattributes a cause by focusing on a smaller portion of a larger set—specifically, the last or least known—and claiming that that cause holds a unique priority over other contributing factors for the occurrence of an event. We propose to call this fallacy (...) the “last straw fallacy” and will argue why these examples actually warrant a new logical name. Finally, we will show how these cases point to a deeper insight about the contexts in which we typically invoke this type of reasoning and some significant harmful consequences of doing so. (shrink)

The paper examines Walton‘s concept of fallacy as it develops throughthree stages of his work: from the early series of papers co-authored withJohn Woods; through a second phase of involvement with thepragma-dialectical perspective; and on to the final phase in which heoffers a distinct pragmatic theory that reaches beyond the perceived limitsof the pragma-dialectical account while still exhibiting a debt to thatperspective and the early investigations with Woods. It is observed how Walton‘s model of fallacy is established in distinction to (...) its competitors,and its various problems and successes are discussed. (shrink)

Informal logic is a method of argument analysis which is complementary to that of formal logic, providing for the pragmatic treatment of features of argumentation which cannot be reduced to logical form. The central claim of this paper is that a more nuanced understanding of mathematical proof and discovery may be achieved by paying attention to the aspects of mathematical argumentation which can be captured by informal, rather than formal, logic. Two accounts of argumentation are considered: the pioneering (...) work of Stephen Toulmin [The uses of argument, Cambridge University Press, 1958] and the more recent studies of Douglas Walton, [e.g. The new dialectic: Conversational contexts of argument, University of Toronto Press, 1998]. The focus of both of these approaches has largely been restricted to natural language argumentation. However, Walton’s method in particular provides a fruitful analysis of mathematical proof. He offers a contextual account of argumentational strategies, distinguishing a variety of different types of dialogue in which arguments may occur. This analysis represents many different fallacious or otherwise illicit arguments as the deployment of strategies which are sometimes admissible in contexts in which they are inadmissible. I argue that mathematical proofs are deployed in a greater variety of types of dialogue than has commonly been assumed. I proceed to show that many of the important philosophical and pedagogical problems of mathematical proof arise from a failure to make explicit the type of dialogue in which the proof is introduced. (shrink)

Why are some arguments fallacious? Since argumentation is an intellectual activity that can be performed better or worse, do we evaluate arguments simply in terms of their content, or does it also make sense to evaluate the arguer in light of the content put forward? From a ‘virtue’ approach, I propose understanding fallacies as having some link with intellectual vice. Drawing from recent work by Paul Grice, Linda Zagzebski, Andrew Aberdein, and Douglas Walton, this essay argues that if there (...) is some sense of argumentation where an argument is truth-propagating and not put forward in order to ‘win’, fallacies may be the vicious element in arguments that undermines, most often because the arguer’s goal is only. From this perspective, fallacies may not only be improper ‘moves’ in an argument, but may also reveal something lacking in the arguer’s intellectual character. (shrink)

Douglas N. Walton considers the question of whether the conventions of informal conversation can be articulated more precisely than they are at present. Specifically, he addresses the problem of the fallacy of ad hominem argumentation as it occurs in natural settings. Can rules be formulated to determine if criticisms of apparent hypocrisy in an argument are defensible or refutable? Walton suggests that they can, and ultimately defends the thesis that ad hominem reasoning is not fallacious per se. He carries (...) his analysis to the core of action--theoretic reasoning--by examining a number of specimen arguments. As suggested by the title, the conclusion of ad hominem argument is demonstrated to be relative to the arguer's position. In the appendixes of the book, articles by Gerald McAuliffe and Gordon R. Lowe illustrate vivid and powerful cases in which Walton's contentions are put to the test. (shrink)

The ad baculum is not a fallacy in an argument, but is offered instead of an argument to put an end to further argument. This claim is the basis for criticizing Michael Wreen's "neo-traditionalism," which yields misreadings of supposed cases of the ad baculum because of its rejection of any consideration of what the person using the ad baculum, or someone who refers to that use as an "argument," is doing. The paper concludes with reflections on the values that should (...) inform talk of a fallacy in an argument such as the one that Wreen is giving. (shrink)

Our article identifies and describes the metaphoric fallacy to a deductive inference (MFDI) that is an example of incorrect reasoning along the lines of the false analogy fallacy. The MFDI proceeds from informal semantical (metaphorical) claims to a supposedly formally deductive and necessary inference. We charge that such an inference is invalid. We provide three examples of the MFDI to demonstrate the structure of this invalid form of reasoning. Our goal is to contribute to the set of known (...) class='Hi'>informal fallacies. (shrink)

We have been oversold on the base rate fallacy in probabilistic judgment from an empirical, normative, and methodological standpoint. At the empirical level, a thorough examination of the base rate literature (including the famous lawyer–engineer problem) does not support the conventional wisdom that people routinely ignore base rates. Quite the contrary, the literature shows that base rates are almost always used and that their degree of use depends on task structure and representation. Specifically, base rates play a relatively larger role (...) in tasks where base rates are implicitly learned or can be represented in frequentist terms. Base rates are also used more when they are reliable and relatively more diagnostic than available individuating information. At the normative level, the base rate fallacy should be rejected because few tasks map unambiguously into the narrow framework that is held up as the standard of good decision making. Mechanical applications of Bayes's theorem to identify performance errors are inappropriate when (1) key assumptions of the model are either unchecked or grossly violated, and (2) no attempt is made to identify the decision maker's goals, values, and task assumptions. Methodologically, the current approach is criticized for its failure to consider how the ambiguous, unreliable, and unstable base rates of the real world are and should be used. Where decision makers' assumptions and goals vary, and where performance criteria are complex, the traditional Bayesian standard is insufficient. Even where predictive accuracy is the goal in commonly defined problems, there may be situations (e.g., informationally redundant environments) in which base rates can be ignored with impunity. A more ecologically valid research program is called for. This program should emphasize the development of prescriptive theory in rich, realistic decision environments. (shrink)

This chapter focuses on one of the common fallacies in Western philosophy, etymological fallacy (EF). To understand the EF fully, it is important to break down the word etymology, which is a practice that in itself informs the conversation surrounding the fallacy. EF is a willful use of a former definition of a word that has changed meaning and/or developed new connotations because the change does not benefit the one committing the fallacy. To avoid committing the EF, individuals should (...) approach language as they would a scientific process: they may hypothesize the word means X, but after further research and consideration, realize that indeed a word now means Y. Either way, the changing nature of language must be considered and individuals should be learned enough and flexible enough to communicate within the time and culture they inhabit. Clinging to etymons while ignoring the evolution and everyday use of language is neither logical nor truthful. (shrink)

Popular textbook treatments of the fallacies approach to argument evaluation employ the Adversary Method identified by Janice Moulton (1983) that takes the goal of argumentation to be the defeat of other arguments and that narrows the terms of discourse in order to facilitate such defeat. My analysis of the textbooks shows that the Adversary Method operates as a Kuhnian paradigm in philosophy, and demonstrates that the popular fallacies pedagogy is authoritarian in being unresponsive to the scholarly developments in (...) informal logic and argumentation theory. A progressive evolution for the fallacies approach is offered as an authoritative alternative. (shrink)

This chapter focuses on one of the common fallacies in Western philosophy called 'genetic fallacy' (GnF). One commits the GnF when advocating for a conclusion based solely on origin. This is a fallacy of relevance—irrelevance, really—because the origin of a claim may be irrelevant to its truth‐value. That is to say, providing an account of the genesis of a claim, its history or origin, may be informative and helpful; however, it need not determine the truth‐value of the claim. Therefore, (...) when one draws a conclusion regarding the truth‐value of a claim based solely on the origin of the claim, then one may have committed the GnF. In the ethical language of “means and ends” reasoning, GnF helps to highlight the problematic nature of the utilitarian‐style disconnect between the justice of actions and the goodness of their consequences. (shrink)

The paper critically investigates the pragma-dialectics of van Eemeren and Grootendorst, particularly the treatment of fallacies. While the pragma-dialectieians claim that dialectics combines the logical and rhetorical approaches to argumentation, it is argued here that the perspective relies heavily on rhetorical features that have been suppressed in the account and that overlooking these features leads to significant problems in the pragma-dialectical perspective. In light of these problems, the author advocates turning attention to a rhetorical account which subsumes the logical (...) and dialectical. (shrink)

When processing political arguments, people are strongly affected by their prior ideological beliefs. Political cognition often relies on two types of ideological biases. Firstly, confirmation bias leads addressees of political communication to accept arguments that affirm their preferred ideological positions. Secondly, disconfirmation bias probes reasoners to reject arguments that provide attitudinally incongruent evidence. Here, we report the findings of an experiment aimed at investigating the role of biased reasoning on perceptions of argument soundness. We focused on the processing of the (...) strawman fallacy to determine whether strawman effectiveness is contingent upon the activation of different ideological biases. We examined argument comprehension, argument evaluation and fallacy identification by means of a memory task, a rating task and an interview. Our data suggests that ideological biases and fallacy effect are associated with deliberative cognitive settings and marks a distinction between evaluative attitudes and the capacity to identify fallacies in political argumentation. (shrink)

In this paper, it is shown how formal dialectic can be extended to model multi-agent argumentation in which each participant is an agent. An agent is viewed as a participant in a dialogue who not only has goals, and the capability for actions, but who also has stable characteristics of types that can be relevant to an assessment of some of her arguments used in that dialogue. When agents engage in argumentation in dialogues, each agent has a credibility function that (...) can be adjusted upwards or downwards by certain types of arguments brought forward by the other agent in the dialogue. One type is the argument against the person or argumentum ad hominem, in which personal attack on one party's character is used to attack his argument. Another is the appeal to expert opinion, traditionally associated with the informal fallacy called the argumentum ad verecundiam. In any particular case, an agent will begin a dialogue with a given degree of credibility, and what is here called the credibility function will affect the plausibility of the arguments put forward by that agent. In this paper, an agent is shown to have specific character traits that are vital to properly judging how this credibility function should affect the plausibility of her arguments, including veracity, prudence, sincerity and openness to opposed arguments. When one of these traits is a relevant basis for an adjustment in a credibility function, there is a shift to a subdialogue in which the argumentation in the case is re-evaluated. In such a case, it is shown how the outcome can legitimately be a reduction in the credibility rating of the arguer who was attacked. Then it is shown how the credibility function should be brought into an argument evaluation in the case, yielding the outcome that the argument is assigned a lower plausibility value. (shrink)

100+ logical, both formal and informal, fallacies explained and illustrated by important and famous arguments made in the history of philosophy.