Fallacies

The standard definition of “argument” is satisfied by any series of statements in which one (of the statements) is marked as the conclusion of the others. This leads to the counter-intuitive result that “I like cookies, therefore, all swans are white” is an argument, since “therefore” marks “all swans are white” as the conclusion of “I like cookies”. This objection is often disregarded by stating that, although the previous sequence is an argument, it fails to be a good one. However, (...) when we compare our previous argument with a definitely bad argument like “this swan is white, therefore, all swans are white”, we see that there is an important difference between them. Whereas the former fails to fulfil our intuition of what an argument is, the latter does qualify as an argument, but as a bad one. In this talk, I will sketch a definition that better captures this feature of our intuition of what an argument is in three steps. Following Díez and Moulines (1999), I first reduce inductive validity to deductive validity through what we may call the method of deductivisation. Second, through epistemic predicates (cf. Thompson 2002), I introduce a broader concept of validity that accounts not only for deductive and inductive validity, but also for a weaker type of validity that may be called pseudo-validity. I show that these pseudo-valid arguments can also be deductivised with the help of the above-mentioned epistemic predicates. Finally, I re-define the concept of argument as any series of statements that is at least pseudo-valid, which leaves the “cookies argument” outside of this definition. (shrink)

There is almost a consensus among conditional experts that indicative conditionals are not material. Their thought hinges on the idea that if indicative conditionals were material, A → B could be vacuously true when A is false, even if B would be false in a context where A is true. But since this consequence is implausible, the material account is usually regarded as false. It is argued that this point of view is motivated by the grammatical form of conditional sentences (...) and the symbols used to represent their logical form, which misleadingly suggest a one-way inferential direction from A to B. That conditional sentences mislead us into a directionality bias is a phenomenon that is well-documented in the literature about conditional reasoning. It is argued that this directional appearance is deceptive and does not reflect the underlying truth conditions of conditional sentences. This directional bias is responsible for both the unpopularity of the material account of conditionals and some of the main alternative principles and themes in conditional theory, including the Ramsey’s test, the Equation, Adams’ thesis, conditional-assertion and possible world theories. The directional mindset forgets a hard- earned lesson that made classical logic possible in the first place, namely, that grammatical form of sentences can mislead us about its truth conditions. There is a case to be made for a material account of indicative conditionals when we break the domination of words over the human mind. (shrink)

The fallacy fallacy is either the misdiagnosis of fallacy or the supposition that the conclusion of a fallacy must be a falsehood. This paper explores the relevance of these and related errors of reasoning for the appraisal of arguments, especially within virtue theories of argumentation. In particular, the fallacy fallacy exemplifies the Owl of Minerva problem, whereby tools devised to understand a norm make possible new ways of violating the norm. Fallacies are such tools and so are vices. Hence a (...) similar problem arises with argumentative vices. Fortunately, both instances of the problem have a common remedy. (shrink)

"A Little More Logical" is the perfect guide for anyone looking to improve their critical thinking and logical reasoning skills. With chapters on everything from logic basics to fallacies of weak induction to moral reasoning, this book covers all the essential concepts you need to become a more logical thinker. You'll learn about influential figures in the field of logic, such as Rudolph Carnap, Betrrand Russell, and Ada Lovelace, and how to apply your newfound knowledge to real-world situations. Whether you're (...) looking to engage in debates with others, make better decisions in your personal and professional life, or simply want to improve your overall critical thinking skills, "A Little More Logical" has you covered. So why wait? Start learning and become a little more logical today! -/- "A Little More Logical" differs from typical logical textbooks in a number of ways. One key difference is its emphasis on engaging and relatable examples and case studies. Rather than simply presenting dry definitions and concepts, the book uses fables, stories, and real-world situations to illustrate key ideas and make them more relatable for readers. -/- Another unique aspect of "A Little More Logical" is its inclusion of "Minds that Mattered" sections, which highlight the contributions and insights of influential figures in the field of logic and critical thinking. These sections provide readers with a deeper understanding of the history and development of logical principles and offer valuable context for the concepts being discussed. -/- Additionally, "A Little More Logical" covers a wide range of topics beyond the basics of logic and argument evaluation. Chapters on moral reasoning, probability and inductive logic, scientific reasoning, conspiracy theories, statistical reasoning, and the history of formal logic offer a more comprehensive and well-rounded understanding of logic and critical thinking. -/- Overall, "A Little More Logical" stands out as a dynamic and engaging resource for anyone looking to improve their logical reasoning abilities. Its relatable examples, historical context, and broad coverage make it a valuable resource for anyone interested in mastering the principles of logic. -/- This is a free, Creative-Commons-licensed book. (shrink)

This book analyses the straw man fallacy and its deployment in philosophical reasoning. While commonly invoked in both academic dialogue and public discourse, it has not until now received the attention it deserves as a rhetorical device. Scott Aikin and John Casey propose that straw manning essentially consists in expressing distorted representations of one's critical interlocutor. To this end, the straw man comprises three dialectical forms, and not only the one that is usually suggested: the straw man, the weak man (...) and the hollow man. Moreover, they demonstrate that straw manning is unique among fallacies as it has no particular logical form in itself, because it is an instance of inappropriate meta-argument, or argument about arguments. They discuss the importance of the onlooking audience to the successful deployment of the straw man, reasoning that the existence of an audience complicates the dialectical boundaries of argument. Providing a lively, provocative and thorough analysis of the straw man fallacy, this book will appeal to postgraduates and researchers alike, working in a range of fields including fallacies, rhetoric, argumentation theory and informal logic. (shrink)

The tradition of Nyāya philosophy centers on a dispassionate quest for truth which is simultaneously connected to soteriological and epistemic aims. This article shows how Vācaspati Miśra brings together the soteriological concept of dispassion with the discourse practices of debate, as a response to Buddhist criticisms in Dharmakīrti’s Vādanyāya. He defends the Nyāyasūtra’s stated position that fallacious reasoning is a legitimate means for a debate, under certain circumstances. Dharmakīrti argues that such reasoning is rationally ineffective and indicates unvirtuous qualities. For (...) Vācaspati, fallacies are a way to prevent the spread of morally weighty falsehoods when no other method is available to a debater. After showing textual relationships between Vācaspati’s defense and Dharmakīrti’s earlier criticism, it evaluates their arguments, concluding that Vācaspati’s position involves irresolvable tensions with other Nyāya commitments. (shrink)

Eristic has been studied more and more intensively in recent years in philosophy, law, communication theory, logic, proof theory, and A.I. Nevertheless, the modern origins of eristic, which almost all current researchers see in the philosopher Arthur Schopenhauer, are considered to be a theory of the illegitimate use of logical and rhetorical devices. Thus, eristic seems to violate the norms of discourse ethics. In this paper, I argue that this interpretation of eristic is based on prejudices that contradict the original (...) intention of modern eristic. Eristic is not an art of being right or winning an argument, but an art of protecting oneself from the one who deliberately violates norms of discourse ethics to gain argumentative acceptance. For this reason, eristic must be seen as a discipline of Enlightenment philosophy and a correlate of discourse ethics. Especially in the age of alternative facts and post-factual politics, this makes eristic a valuable discipline. (shrink)

In this paper, we analyze and discuss Schopenhauer’s n-term diagrams for eristic dialectics from a graph-theoretical perspective. Unlike logic, eristic dialectics does not examine the validity of an isolated argument, but the progression and persuasiveness of an argument in the context of a dialogue or even controversy. To represent these dialogue situations, Schopenhauer created large maps with concepts and Euler-type diagrams, which from today’s perspective are a specific form of graphs. We first present the original method with Euler-type diagrams, then (...) give the most important graph-theoretical definitions, then discuss Schopenhauer’s diagrams graph-theoretically and finally give an example of how the graphs or diagrams can be used to analyze dialogues. (shrink)

The fallacy of ignoring qualifications, or secundum quid et simpliciter, is a deceptive strategy that is pervasive in argumentative dialogues, discourses, and discussions. It consists in misrepresenting an utterance so that its meaning is broadened, narrowed, or simply modified to pursue different goals, such as drawing a specific conclusion, attacking the interlocutor, or generating humorous reactions. The “secundum quid” was described by Aristotle as an interpretative manipulative strategy, based on the contrast between the “proper” sense of a statement and its (...) meaning taken absolutely or in a certain respect. However, how can an “unqualified” statement have a proper meaning different from the qualified one, and vice versa? This “linguistic” fallacy brings to light a complex relationship between pragmatics, argumentation, and interpretation. The secundum quid is described in this paper as a manipulative argument, whose deceptive effect lies in its pragmatic dimension. This fallacy is analyzed as a strategy of decontextualization lying at the interface between pragmatics and argumentation and consisting of the unwarranted passage from an ut-terance to its semantic representation. By ignoring the available evidence and the presumptive interpretation of a statement, the speaker places it in a different context or suppresses textual and contextual evidence to infer a specific meaning different from the presumable one. (shrink)

An argumentation profile is defined as a methodological instrument for analyzing argumentative discourse considering distinct and interrelated dimensions: the types of argument used, their quality, and the emotions triggered. Walton’s theoretical contributions are developed as a coherent analytical and multifaceted toolbox for capturing these aspects. Argumentation schemes are used to detect and quantify the types of argument. Fallacy analysis and the assessment of the implicit premises retrieved through the schemes allow evaluating arguments. Finally, the frequency of emotive words signals the (...) most common emotions aroused. This method is illustrated through a corpus of argumentative tweets of three politicians. (shrink)

Douglas Walton’s work is extremely vast, multifaceted, and interdisciplinary. He developed theoretical proposals that have been used in disciplines that are not traditionally related to philosophy, such as law, education, discourse analysis, artificial intelligence, or medical communication. Through his papers and books, Walton redefined the boundaries not only of argumentation theory, but also logic and philosophy. He was a philosopher in the sense that his interest was developing theoretical models that can help explain reality, and more importantly interact with it. (...) For this reason, he proposed methods that have been used for analyzing different types of dialogical interactions, and modeling procedures for regulating them. (shrink)

In this paper, I study the relation between arguments against the person (aka ad hominem or personal attack arguments) and disqualifications for conflicts of interests. I show that both types of arguments share a similar logical structure and that they can be considered to be acceptable in similar circumstances.

In the last decades Human-Computer Interaction (HCI) has started to focus attention on “persuasive technologies” having the goal of changing users’ behavior and attitudes according to a predefined direction. In this talk we show how some of the techniques employed in such technologies trigger some well known cognitive biases by adopting a strategy relying on logical fallacies (i.e. forms of reasoning which are logically invalid but psychologically persuasive). In particular, we will show how the mechanisms reducible to logical fallacies are (...) used to design web and mobile interfaces in domains ranging from the e-commerce to the jihadist propaganda. The final part of the talk will be devoted to point out the potential ethical dangers related to the misuse of these techniques in the design of persuasive technologies. (shrink)

The global emergency caused by the spread of COVID-19 raises critical challenges for individuals and communities on many different levels. In particular, politicians, scientists, physicians, and other professionals may face new ethical dilemmas and cognitive constraints as they make critical decisions in extraordinary circumstances. Philosophers and cognitive scientists have long analyzed and discussed such issues. An example is the debate on moral decision making in imaginary scenarios, such as the famous “Trolley Problem”. Similarly, dramatic and consequential decisions are realized daily (...) in the current crisis. Focusing on Italy, we discuss the clinical ethical guidelines proposed by the Italian Society of Anesthesiology, Analgesia, Resuscitation and Intensive Care, highlighting some crucial ethical and cognitive concerns surrounding emergency decision making in the current situation. (shrink)

Jeśli można mówić o modzie w badaniach naukowych, to semantyka jest od prawie wieku niewątpliwie jedną z bardziej modnych dziedzin w nauce. Badają ją nie tylko logicy i filozofowie języka, lecz także kulturoznawcy, antropologowie, filologowie, kognitywiści czy informatycy. Niniejszy artykuł ma na celu zbadanie roli, jaką odgrywa semantyka w teorii argumentacji, a dokładniej — zarysowanie pewnego modelu argumentacji, który modyfikuje znaczenia terminów dla celów argumentacyjnych. Najpierw przedstawię kilka przykładowych argumentów semantycznych, analizując każdy z nich na tyle, aby wydobyć pewne subtelności (...) potrzebne do zbudowania modelu argumentu semantycznego. W ten sposób pokażę, jak nomen omen znaczący wpływ na argumentację ma znaczenie słów, a także na ile sposobów może ono wpływać na przebieg argumentacji. Na samym końcu zarysuję definicję argumentu semantycznego, która może wytyczyć kierunek dalszych badań nad semantyką w teorii argumentacji. (shrink)

I shall show that the main argument forms of Wittgenstein's Tractatus and Kant's Critique of Pure Reason are Modus Tollens. I shall then argue that the main arguments of both books beg the question by addressing only one sub-argument in each, although it is still in controversy whether begging the question is a genuine fallacy.

This paper builds a nine-step method for determining whether a straw man fallacy has been committed in a given case or not, by starting with some relatively easy textbook cases and moving to more realistic and harder cases. The paper shows how the type of argument associated with the fallacy can be proved to be a fallacy in a normative argumentation model, and then moves on to the practical task of building a hands-on method for applying the model to real (...) examples of argumentation. Insights from linguistic pragmatics are used to distinguish the different pragmatic processes involved in reconstructing what is said and what is meant by an utterance, and to differentiate strong and weak commitments. In particular, the process of interpretation is analyzed in terms of an abductive pattern of reasoning, based on co-textual and contextual information, and assessable through the instruments of argumentation theory. (shrink)

Political conspiracy theories—e.g., unsupported beliefs about the nefarious machinations of one’s cunning, powerful, and evil opponents—are adopted enthusiastically by a great many people of widely varying political orientations. In many cases, these theories posit that there exists a small group of individuals who have intentionally but secretly acted to cause economic problems, political strife, and even natural disasters. This group is often held to exist “in the shadows,” either because its membership is unknown, or because “the real nature” of its (...) members’ allegiances, motives, and methods has been concealed from the public at large. Paradigmatic examples of these political conspiracy theories include anti-Semitic beliefs of the sort associated with The Protocols of the Elder of Zion, the “Red Scare” of the 1950s, claims about the “New World Order,” and many others. -/- Why do these theories attract so many adherents? In this essay, I’ll attempt to spread some light on this issue by applying Kahneman and Tversky’s highly influential work on reasoning under uncertainty. I’ll proceed by first providing a brief introduction to Kahneman and Tversky’s work on reasoning under uncertainty, and the way in which this relates to standard economic and philosophic accounts of rational behavior, as well as philosophical ideas about the role of intuition. Next, I’ll move onto some specific interconnected aspects of this work that are relevant to understanding conspiracy theories, including errors involving probabilistic reasoning (“Prospect Theory”), those involving the inappropriate use of heuristics, and those related to the “framing” of certain outcomes as losses from a baseline. This essay will conclude by making two related points. First, some of the most important reasoning errors committed by adherents of conspiracy theories are errors that many of us regularly commit. Given that self-awareness of these errors provides only minimal protection from committing them, this suggests that many of use may be more vulnerable to conspiratorial reasoning than we may like to believe. Second, in the light of this danger, I will outline a few steps that might be taken to help inoculate ourselves against the appeal of these theories, and to help respond to the conspiratorial arguments of others. (shrink)

Objetivamos discutir a crítica, avançada por Colin Howson em Hume's problem, segundo a qual o argumento do milagre (doravante, AM) comete a falácia da taxa-base. Por falácia da taxa-base, entende-se a negligência do valor da probabilidade prévia de determinada hipótese ou teoria T, P(T). Por sua vez, em uma de suas versões, AM assere que apenas assumindo que uma teoria científica madura T é aproximadamente verdadeira não faz de seu sucesso preditivo um milagre. Formalizado probabilisticamente, Howson argumenta que a conclusão (...) de AM, a probabilidade de que a teoria T seja aproximadamente verdadeira é grande, apenas se segue se assumirmos para T um valor não-negligenciável. Tal crítica de Howson despertou duas categorias de reação na literatura especializada: supondo que AM comete a falácia da taxa base, alguns autores propuseram abandonar AM enquanto um argumento para a tese epistemológica do realismo científico, ao passo que outros defenderam que apenas uma versão de AM comete a falácia da taxa-base; defendendo que AM não comete a falácia da taxa base, certos autores alegaram alguns problemas na formalização probabilística de AM, enquanto outros buscaram refinar tal formalização de modo que a nova evite a falácia em questão. Tendo apresentado esse estado da arte, investigaremos se a formalização probabilística do argumento do milagre é razoável. Discutiremos se ela acomoda a natureza de inferência à melhor explicação pressuposta no AM. Por fim, indicaremos, brevemente, algumas dificuldades para a crítica de Howson ao assumir-se que AM instancia, na verdade, uma abdução Peirceana. (shrink)

This textbook is not a textbook in the traditional sense. Here, what we have attempted is compile a set of assignments and exercise that may be used in critical thinking courses. To that end, we have tried to make these assignments as diverse as possible while leaving flexibility in their application within the classroom. Of course these assignments and exercises could certainly be used in other classes as well. Our view is that critical thinking courses work best when they are (...) presented as skills based learning opportunities. We hope that these assignments speak to that desire and can foster the kinds of critical thinking skills that are both engaging and fun Please feel free to contact us with comments and suggestions. We will strive to correct errors when pointed out, add necessary material, and make other additional and needed changes as they arise. Please check back for the most up to date version. Rebeka Ferreira and Anthony Ferrucci. (shrink)

ABSTRACTIn order to explain the effects found in the heuristics and biases literature, dual-process theories of reasoning claim that human reasoning is of two kinds: Type-1 processing is fast, automatic, and associative, while Type-2 reasoning is slow, controlled, and rule based. If human reasoning is so divided, it would have important consequences for morality, epistemology, and philosophy of mind. Although dual-process theorists have typically argued for their position by way of an inference to the best explanation, they have generally failed (...) to consider alternative hypotheses. Worse still, it is unclear how we might test dual-process theories. In this article, I offer a one-system theory, which I call the Sound-Board Account of Reasoning, according to which there is one reasoning system which is flexible, allowing the properties used to distinguished Type-1 and Type-2 reasoning to cross-cut one another. I empirically distinguish my theory from the two dominant versions of dual-process theory (parallel... (shrink)

Exposing Fake Logic by Avi Sion is a collection of essays written after publication of his book A Fortiori Logic, in which he critically responds to derivative work by other authors who claim to know better. This is more than just polemics; but allows further clarifications of a fortiori logic and of general logic. This collection includes essays on: a fortiori argument (in general and in Judaism); Luis Duarte D’Almeida; Mahmoud Zeraatpishe; Michael Avraham (et al.); an anonymous reviewer of BDD (...) (a Bar Ilan University journal); and self-publishing. (shrink)

This paper explains a fallacy that often arises in theorizing about human minds. I call it the Factual Belief Fallacy. The Fallacy, roughly, involves drawing conclusions about human psychology that improperly ignore the large backgrounds of mostly accurate factual beliefs people have. The Factual Belief Fallacy has led to significant mistakes in both philosophy of mind and cognitive science of religion. Avoiding it helps us better see the difference between factual belief and religious credence; seeing that difference in turn enables (...) us to pose interesting normative questions about various mental states labeled “belief.”. (shrink)

Plausibly, an inference is an act of coming to believe something on the basis of something else you already believe. But what is it to come to believe some- thing on the basis of something else? I propose a disjunctive answer: it is either for some beliefs to rationally cause another—where rational causation is understood as causation that is either actually or potentially productive of knowledge—or for some beliefs to “deviantly” cause another, but for the believer mistakenly to come thereby (...) to believe that the former have rationally caused the latter. The result, I argue, is both a theoretically satisfying account of the act of inferring and a demonstration of the power of a knowledge-first approach to the philosophy of mind. (shrink)

We present a formal measure of argument strength, which combines the ideas that conclusions of strong arguments are (i) highly probable and (ii) their uncertainty is relatively precise. Likewise, arguments are weak when their conclusion probability is low or when it is highly imprecise. We show how the proposed measure provides a new model of the Ellsberg paradox. Moreover, we further substantiate the psychological plausibility of our approach by an experiment (N = 60). The data show that the proposed measure (...) predicts human inferences in the original Ellsberg task and in corresponding argument strength tasks. Finally, we report qualitative data taken from structured interviews on folk psychological conceptions on what argument strength means. (shrink)

I present three critical points against G.E.R. Lloyd's ‘The Fortunes of Analogy’. First, I argue that Lloyd unduly criticises Aristotle's view of analogies. Second, I argue that Lloyd needs to discuss the means of limiting the semantic stretch of terms, for instance through the distinction between fiat and bona fide boundaries. Third, I point out some terminological issues in Lloyd's account, especially concerning the applicability of validity, soundness, and fallaciousness to analogies.

According to Thagard, the behavior of practitioners of a field may also be used for demarcation between science and pseudoscience due to its social dimension in addition to the epistemic one. I defended the tendency of pseudoscientists to commit fallacies, and the number of fallacies they commit can be a secondary tool for demarcation problem and this tool is consistent with Thagardian approach. In this paper, I selected the astrology as the case and I revealed nine types of logical fallacies (...) frequently committed by astrologers while introducing their field and/or defending their claims against the scientific inquiries and refutation efforts. I also argued that recognizing these fallacies may help the audience to demarcate between the scientific and the pseudoscientific arguments. (shrink)

What should a virtue theory of argumentation say about fallacious reasoning? If good arguments are virtuous, then fallacies are vicious. Yet fallacies cannot just be identified with vices, since vices are dispositional properties of agents whereas fallacies are types of argument. Rather, if the normativity of good argumentation is explicable in terms of virtues, we should expect the wrongness of bad argumentation to be explicable in terms of vices. This approach is defended through analysis of several fallacies, with particular emphasis (...) on the ad misericordiam. (shrink)

Research into the cognition of conditionals has predominantly focused on conditional reasoning, producing a range of theories which explain associated phenomena with considerable success. However, such theories have been less successful in accommodating experimental data concerning how agents assess the probability of indicative conditionals. Since an acceptable account of conditional reasoning should be compatible with evidence regarding how we evaluate conditionals’ likelihoods, this constitutes a failing of such theories. Section 1 introduces the most dominant established approach to conditional reasoning: mental (...) models theory. Surveying a range of experimental results, I show that mental models theory (along with competing theories) is incapable of fully accounting for findings regarding judgements about conditionals’ probabilities. Section 2 introduces an alternative account of deductive reasoning, the erotetic theory, recently proposed by Koralus and Mascarenhas (2013). Section 3 argues that, given a natural extension, this theory is able to explain the otherwise unaccounted for data. (shrink)

According to an argument by Colin Howson, the no-miracles argument is contingent on committing the base-rate fallacy and is therefore bound to fail. We demonstrate that Howson’s argument only applies to one of two versions of the NMA. The other version, which resembles the form in which the argument was initially presented by Putnam and Boyd, remains unaffected by his line of reasoning. We provide a formal reconstruction of that version of the NMA and show that it is valid. Finally, (...) we demonstrate that the use of subjective priors is consistent with the realist implication of the NMA and show that a core worry with respect to the suggested form of the NMA can be dispelled. (shrink)

: In this paper we examine two challenges to the orthodox understanding of the fallacy of denying the antecedent. One challenge is to say that passages thought to express the fallacy can usually be given an interpretation on which they express valid arguments, entitling us to query whether the fallacy is commonly, if ever, committed at all. We discuss this claim in Section 1. The second challenge comes from those who think that there are legitimate uses of denying the antecedent (...) that have traditionally been overlooked. In Section 2 we propose a general test for claims of this sort, and assess three versions of this view. (shrink)

Throughout the history of analytic philosophy the notion of the ‘phenomenological fallacy’ originally formulated by Place, has been used to criticize reification of the mental. Although this fallacy was originally not used to criticize the phenomenological tradition, it has popped up recently in debates between analytic philosophers and phenomenologists. However, a study of the history of both traditions reveals that a polemical notion similar, if not identical, to the phenomenological fallacy can be found within the phenomenological tradition, namely Sartre’s ‘illusion (...) of immanence’. In this article, I will explicate these two polemical notions and place them in the context of their respective traditions. This will reveal that both notions must be understood as a criticism of a certain form of representationalism I will call ‘dual-world representationalism’. This deep-rooted similarity between the analytic philosophy of mind and phenomenology, in turn, sheds a new light on current discussions between the two traditions. (shrink)

Many of us read Peter Singer ’ s work on our obligations to those in desperate need with our students. Famously, Singer argues that we have a moral obligation to give a significant portion of our assets to famine relief. If my own experience is not atypical, it is quite common for students, upon grasping the implications of Singer ’ s argument, to ask whether Singer gives to famine relief. In response it might be tempting to remind students of the (...) ad hominem fallacy of attacking the person advancing an argument rather than the argument itself. In this paper I argue that the “ ad hominem reply ” to students ’ request for information about Singer is misguided. First I show that biographical facts about the person advancing an argument can constitute indirect evidence for the soundness / unsoundness of the argument. Second, I argue that such facts are relevant because they may reveal that one can discard the argument without thereby incurring moral responsibility for failing to act on its conclusion even if the argument is sound. (shrink)

In this paper, I reply to Seidel’s objections against my argument from expert performance to the effect that arguments from expert opinion are weak arguments. I clarify what Seidel takes to be unclear points in my argument and show that it withstands Seidel’s objections.

In response to the claim that the properties typically used to distinguish System 1 from System 2 crosscut one another, Carruthers, Evans, and Stanovich have abandoned the System 1/System 2 distinction. Evans and Stanovich both opt for a dual-process theory, according to which Type-1 processes are autonomous and Type-2 processes use working memory and involve cognitive decoupling. Carruthers maintains a two-system account, according to which there is an intuitive system and a reflective system. I argue that these defenses of dual-process (...) theory face two problems. First, as pointed out by Sloman, these new dual-process theories cast the net of “reasoning” too wide. Second, and more importantly, this singular distinction cannot accomplish the explanatory work needed to support dual-process theory. These theorists must fall back on using various properties from the Standard Menu in explanations, thereby committing these accounts to a “Standard View” that they had hoped to avoid. Thus, these theorists face a.. (shrink)

This paper considers whether universally—for all (known) rational beings—an argument scheme or pattern can go from being cogent (well-reasoned) to fallacious. This question has previously received little attention, despite the centrality of the concepts of cogency, scheme, and fallaciousness. I argue that cogency has vanished in this way for the following scheme, a common type of impersonal means-end reasoning: X is needed as a basic necessity or protection of human lives, therefore, X ought to be secured if possible. As it (...) stands (with no further elaboration), this scheme is committed to the assumption that the greater the number of human lives, the better. Although this assumption may have been indisputable previously, it is clearly disputable now. It is a fallacy or non sequitur to make a clearly disputable assumption without providing any justification. Although this topic raises critical issues for practically every discipline, my primary focus is on logical (as opposed to empirical or ethical) aspects of the case, and on implications for practical and theoretical logic. I conclude that the profile of vanishing cogency of the scheme may be unique and is determined by a peculiar combination of contingent universality and changing conditions. (shrink)

What do you get when you cross a fallacy with a good argument? A fugu, that is, a valid argument that tempts you to reach its conclusion invalidly. You have yielded to the temptation more than you realize. If you are a teacher, you may have served many fugus. They arise systematically through several mechanisms. Fugus are interesting intermediate cases that shed light on the following issues: bare evidentialism, false pleasure, philosophy of education, and the ethics of argument. Normally, a (...) fugu will not yield knowledge from known premises. But if the reasoning is only slightly fallacious, they do yield knowledge. These mild fugus show that we can gain knowledge by invalid reasoning. This is a conservative resource for historians. They want to credit discoveries to Euclid rather than those who made minor corrections to his proofs, such as David Hilbert. We also benefit from this practice of grandfathering in old standards of knowledge attribution. For we can compete spiritedly for priority. We do not need to worry that credit will instead go to future scholars who will make the minor amendments needed to raise present proofs to a future standard of demonstration. (shrink)

Argumentation theorists are beginning to think of ad hominem arguments as generally legitimate. Virtue argumentation theorists argue that a character trait approach to argument appraisal can explain why ad hominems would are legitimate, when they are legitimate. But I argue that we do not need to appeal to virtue argumentation theory to explain the legitimacy of ad hominem arguments; a more straightforward evidentialist approach to argument appraisal is also committed to their legitimacy. I also argue that virtue argumentation theory faces (...) some important problems, and that whereas the virtue-theoretic approach in epistemology is well-motivated, that motivation does not carry over to virtue argumentation theory. (shrink)

Public health communication makes extensive use of a linguistic formulation that will be called the “no evidence” statement. This is a written or spoken statement of the form “There is no evidence that P” where P stands for a proposition that typically describes a human health risk. Danger lurks in these expressions for the hearer or reader who is not logically perspicacious, as arguments that use them are only warranted under certain conditions. The extent to which members of the public (...) are able to determine what those conditions are will be considered by examining data obtained from 879 subjects. The role of “no evidence” statements as cognitive heuristics in public health reasoning is considered. (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)

Examines 21 unquestioned assumptions that cloud our collective consciousness.

Recent work on conditional reasoning argues that denying the antecedent [DA] and affirming the consequent [AC] are defeasible but cogent patterns of argument, either because they are effective, rational, albeit heuristic applications of Bayesian probability, or because they are licensed by the principle of total evidence. Against this, we show that on any prevailing interpretation of indicative conditionals the premises of DA and AC arguments do not license their conclusions without additional assumptions. The cogency of DA and AC inferences rather (...) depends on contingent factors extrinsic to, and independent of, what is asserted by DA and AC arguments. arguments do not license their conclusions without additional assumptions. The cogency of DA and AC inferences rather depends on contingent factors extrinsic to, and independent of, what is asserted by DA and AC arguments. (shrink)