The Holy Scriptures can be considered a specific kind of normative texts, whose use to assess practical moral cases requires interpretation. In the field of ethics, this interpretative problem results in the necessity of bridging the gap between the normative source – moral precepts – and the specific cases. In the history of the Church, this problem was the core of the so-called casuistry, namely the decision-making practice consisting in applying the Commandments and other principles of the Holy Scriptures to (...) specific cases or moral problems. By taking into account the sin of lying, this paper argues that casuistic texts reveal an extremely sophisticated interpretative method, grounded on “pragmatic” contextual and communicative considerations and argumentative structures that resemble the ones used in legal interpretation. These works show how the underspecified biblical text expressing an abstract norm was enriched pragmatically by completing it and modulating its meaning so that it could be used to draw a conclusion in a specific context on a specific case. The mutual interdependence between biblical interpretation, pragmatics, and argumentation sheds light on a much broader phenomenon, namely the pragmatic nature of argumentation. (shrink)

According to the so-called presumption of equality, a person who does not know whether there is an acceptable reason for differential treatment should just presume the similarity of the cases and treat them equally. If we assume that the presumption of equality is an acceptable moral principle, at least when the allocation cannot be postponed and an equal distribution of goods is possible, then an important question arises: when exactly does the allocator have sufficient reasons for differential treatment and is (...) not relevantly ignorant? This is a question about the required strength of the “acceptable reasons” for differential treatment. It has been commonplace to think that the presumption of equality demands that the reasons that refute the presumption must be very strong and that differential treatment requires that there is a proper justification for the claim that the cases are relevantly different. I will argue, however, that refuting the presumption and solving the issue are two separate matters. A person can have good enough reasons for rejecting the presumption that the cases are relevantly similar without having reasons that she could present as a full justification for the claim that the cases are relevantly different. A precondition of the applicability of the presumption of equality is ignorance, but not ignorance in the sense of “not having a full justification”. (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)

“Absence of evidence isn’t evidence of absence” is a slogan that is popular among scientists and nonscientists alike. This article assesses its truth by using a probabilistic tool, the Law of Likelihood. Qualitative questions (“Is E evidence about H ?”) and quantitative questions (“How much evidence does E provide about H ?”) are both considered. The article discusses the example of fossil intermediates. If finding a fossil that is phenotypically intermediate between two extant species provides evidence that those species have (...) a common ancestor, does failing to find such a fossil constitute evidence that there was no common ancestor? Or should the failure merely be chalked up to the imperfection of the fossil record? The transitivity of the evidence relation in simple causal chains provides a broader context, which leads to discussion of the fine-tuning argument, the anthropic principle, and observation selection effects. (shrink)

The Buddhists philosophers put forward a revisionary metaphysics which lacks a “self” in order to provide an intellectually and morally preferred picture of the world. The first task in the paper is to answer the question: what is the “self” that the Buddhists are denying? To answer this question, I look at the Abhidharma arguments for the No-Self doctrine and then work back to an interpretation of the self that is the target of such a doctrine. I argue that Buddhists (...) are not just denying the diachronically unified, extended, narrative self but also minimal selfhood insofar as it associated with sense of ownership and sense of agency. The view is deeply counterintuitive and the Buddhists are acutely aware of this fact. Accordingly, the Abhidharma-Buddhist writings are replete with attempts to explain the phenomenology of experience in a no-self world. The second part of the paper reconstructs the Buddhist explanation using resources from contemporary discussions about the sense of agency. (shrink)

In this overview article, we first explain what we take informal logic to be, discussing misconceptions and distinguishing our conception of it from competing ones; second, we briefly catalogue recent informal logic research, under 14 headings; third, we suggest four broad areas of problems and questions for future research; fourth, we describe current scholarly resources for informal logic; fifth, we discuss three implications of informal logic for philosophy in particular, and take note ofpractical consequences of a more general sort.

The notion of “the burden of proof” plays an important role in real-world argumentation contexts, in particular in law. It has also been given a central role in normative accounts of argumentation, and has been used to explain a range of classic argumentation fallacies. We argue that in law the goal is to make practical decisions whereas in critical discussion the goal is frequently simply to increase or decrease degree of belief in a proposition. In the latter case, it is (...) not necessarily important whether that degree of belief exceeds a particular threshold (e.g., ‘reasonable doubt’). We explore the consequences of this distinction for the role that the “burden of proof” has played in argumentation and in theories of fallacy. (shrink)

Homoeopathy is commonly recognised as pseudoscience. However, there is, to date, no systematic discussion that seeks to establish this view. In this paper, we try to fill this gap. We explain the nature of homoeopathy, discuss the notion of pseudoscience, and provide illustrative examples from the literature indicating why homoeopathy fits the bill. Our argument contains a conceptual and an empirical part. In the conceptual part, we introduce the premise that a doctrine qualifies as a pseudoscience if, firstly, its proponents (...) claim scientific standing for it and, secondly, if they produce bullshit to defend it, such that, unlike science, it cannot be viewed as the most reliable knowledge on its topic. In the empirical part, we provide evidence that homoeopathy fulfils both criteria. The first is quickly established since homoeopaths often explicitly claim scientificity. To establish the second, we dive into the pseudo-academic literature on homoeopathy to provide evidence of bullshit in the arguments of homoeopaths. Specifically, we show that they make bizarre ontological claims incompatible with natural science, illegitimately shift the burden of proof to sceptics, and mischaracterise, cherry-pick, and misreport the evidence. Furthermore, we demonstrate that they reject essential parts of established scientific methodology and use epistemically unfair strategies to immunise their doctrine against recalcitrant evidence. (shrink)

The moving spotlight account (MS) is a view that combines an eternalist ontology and an A-theoretic metaphysics. The intuition underlying MS is that the present time is somehow privileged and experientially vivid, as if it were illuminated by a moving spotlight. According to MS-theorists, a key reason to prefer MS to B-theoretic eternalism is that our experience of time supports it. We argue that this is false. To this end, we formulate a new family of positions in the philosophy of (...) time, which differ from MS in that, intuitively, they admit a plurality of moving spotlights. We argue that these ‘deviant’ variants of MS cannot be dismissed as conceptually incoherent, and that they are as well-supported by our experience as is MS. One of these variants, however, is consistent with the B-theory. Thus, if our experience of time supports MS, then it supports the B-theory as well. (shrink)

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)

The world’s scientific community must be in a state of constant readiness to address the threat posed by newly emerging infectious diseases. Whether the disease in question is SARS in humans or BSE in animals, scientists must be able to put into action various disease containment measures when everything from the causative pathogen to route(s) of transmission is essentially uncertain. A robust epistemic framework, which will inform decision-making, is required under such conditions of uncertainty. I will argue that this framework (...) should have reasoning at its center and, specifically, that forms of reasoning beyond deduction and induction should be countenanced by scientists who are confronted with emerging infectious diseases. In previous articles, I have presented a case for treating certain so-called traditional informal fallacies as rationally acceptable forms of argument that can facilitate scientific inquiry when little is known about an emerging disease. In this article, I want to extend that analysis by highlighting the unique features of these arguments that makes them specially adapted to cope with conditions of uncertainty. Of course, such a view of the informal fallacies must at least be consistent with the reasoning practices of scientists, and particularly those scientists (viz. epidemiologists) whose task it is to track and respond to newly emerging infectious diseases. To this end, I draw upon examples of scientific reasoning from the UK’s BSE crisis, a crisis that posed a significant threat to both human and animal health. (shrink)

In this paper, a solution to the problem of analyzing burden of proof in argumentation is developed by building on the pioneering work of Erik C. W. Krabbe on metadialogues. Three classic cases of burden of proof disputes are analyzed, showing how metadialogue theory can solve the problems they pose. The solution is based on five dialectical requirements: (1) global burden of proof needs to be set at the confrontation stage of a dialogue, (2) there need to be special mechanisms (...) for resolving disputes about burden of proof at all four stages of the dialogue, (3) they are especially significant during the argumentation stage, where burden of proof often shifts back and forth at each move, (4) such local shifts need to be partly regulated by the global burden of proof already set, and (5) the connection between burden of proof and the speech act of making a presumption in a dialogue needs to be clarified. (shrink)

The concept of a witch hunt is frequently invoked, in recent times, to describe a kind of procedure for deciding the guilt of a person against whom an accusation has been made. But what exactly is a witch hunt? In this paper, ten conditions are formulated as a cluster of properties characterizing the witch hunt as a framework in which arguments are used: (1) pressure of social forces, (2) stigmatization, (3) climate of fear, (4) resemblance to a fair trial, (5) (...) use of simulated evidence, (6) simulated expert testimony, (7) nonfalsifiability characteristic of evidence, (8) reversal of polarity, (9) non-openness, and (10) use of the loaded question technique. The witch hunt, as characterized by these criteria, is shown to function as a negative normative structure for evaluating argumentation used in particular cases. (shrink)

This paper discusses the method when an argument is refuted by a parallel argument since the flaw of the parallel argument is clearly displayed. The method is explicated, examined and compared with two other general methods.

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)

This essay is concerned with Indian Yogācāra philosophers’ treatment of the problem of other minds in the face of a threatened collapse into solipsism suggested by Vasubandhu’s epistemological argument for idealism. I discuss the attempts of Dharmakīrti and Ratnakīrti to address this issue, concluding that Dharmakīrti is best seen as addressing the epistemological problem of other minds and Ratnakīrti as addressing the conceptual problem of other minds.

In many contexts a retraction of commitment isfrowned upon. For instance, it is not appreciated,generally, if one withdraws a promise or denies anearlier statement. Critical discussion, too, caneasily be disrupted by retractions, if these occur toofrequently and at critical points. But on the otherhand, the very goal of critical discussion –resolution of a dispute – involves a retraction,either of doubt, or of some expressed point of view.A person who never retracts, not even under pressureof cogent arguments, would hardly qualify as (...) areasonable discussant. Also, inconsistencies in one'sposition, once they have been pointed out, must bedealt with by some kind of retraction. The problem ofretraction is to find a suitable model of dialoguethat allows retractions where they seem reasonable, oreven required, and rules them out (or puts sanctionsupon them) whenever they would become disruptive of awell-organized process of dialogue.The present paper tries to point to a solution basedon the following principles: (1) Retraction rulesdetermine what retractions are permissible, and (2) ifpermissible what the consequences of retraction are.(3) Retraction rules vary according to the type ofdialogue and (4) according to the type of commitmentretracted. For instance, assertions and mereconcessions need to be distinguished, as well aslight-side and dark-side commitments. (5) To accountfor our contradictory intuitions on the issue ofretractions, one may best resort to a complex type ofdialogue in which different retraction rules hold fordifferent parts.The paper explains, summarizes, and expands upon thediscussion of retraction in Commitment inDialogue by Douglas Walton and the present author(cf. Walton and Krabbe 1995). (shrink)

Scientific theories are hard to find, and once scientists have found a theory, H, they often believe that there are not many distinct alternatives to H. But is this belief justified? What should scientists believe about the number of alternatives to H, and how should they change these beliefs in the light of new evidence? These are some of the questions that we will address in this article. We also ask under which conditions failure to find an alternative to H (...) confirms the theory in question. This kind of reasoning is frequently used in science and therefore deserves a careful philosophical analysis. 1 Introduction2 The Conceptual Framework3 The No Alternatives Argument4 Discussion I: A Quantitative Analysis of the No Alternatives Argument5 Discussion II: The Number of Alternatives and the Problem of Underdetermination6 ConclusionsAppendix AAppendix B. (shrink)

Five errors that fit under the category of jumping to a conclusion are identified: (1) arguing from premises that are insufficient as evidence to prove a conclusion (2) fallacious argument from ignorance, (3) arguing to a wrong conclusion, (4) using defeasible reasoning without being open to exceptions, and (5) overlooking/suppressing evidence. It is shown that jumping to a conclusion is best seen not as a fallacy itself, but as a more general category of faulty argumentation pattern underlying these errors and (...) some related fallacies. (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)

Normal 0 0 1 85 487 UBC 4 1 598 11.773 0 0 0 Under what conditions is the failure to have evidence that p evidence that p is false? Absent evidence reasoning is common in many sciences, including astronomy, archeology, biology and medicine. An often-repeated epistemological motto is that “the absence of evidence is not evidence of absence.” Analysis of absent evidence reasoning usually takes place in a deductive or frequentist hypothesis-testing framework. Instead, I develop a Bayesian analysis of (...) this motto and prove that, under plausible assumptions about the nature of evidence, the absence of evidence is evidence of absence. (shrink)

The Covid-19 pandemic presents argumentation theorists with an opportunity to reflect on the ways in which people, agencies and governments respond to the emergence of a new virus. Reponses have revealed a range of judgements and decisions, not all of which are rationally warranted. This article will examine errors in reasoning, several of which have reduced the public’s compliance with important health measures. This article will also analyse rationally warranted reasoning about Covid-19 employed by public health agencies. In examining instances (...) of good and bad reasoning during the Covid-19 pandemic, we can begin to construct a taxonomy of arguments that facilitated and hindered individual and collective responses during this public health emergency. (shrink)

In this article, we argue for the general importance of normative theories of argument strength. We also provide some evidence based on our recent work on the fallacies as to why Bayesian probability might, in fact, be able to supply such an account. In the remainder of the article we discuss the general characteristics that make a specifically Bayesian approach desirable, and critically evaluate putative flaws of Bayesian probability that have been raised in the argumentation literature.

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)

While in the beginning of the environmental debate, conflicts over environmental and technological issues had primarily been understood in terms of ‘‘risk’’, over the past two decades the relevance of ignorance, or nonknowledge, was emphasized. Referring to this shift of attention to nonknowledge the article presents two main findings: first, that in debates on what is not known and how to appraise it different and partly conflicting epistemic cultures of nonknowledge can be discerned and, second, that drawing attention to nonknowledge (...) in technology conflicts results in significant institutional effects and new constellations of actors in public debates. To illustrate and substantiate this political dynamics of nonknowledge we draw upon examples from the areas of agri-biotechnology and mobile phoning. In a first step, we develop in greater detail the concept of scientific cultures of nonknowledge and identify three such cultures involved in the social conflicts within the two areas. Subsequently, we analyze the specific dynamics of the politicisation of nonknowledge looking at the variety of actors involved and the pluralisation of perceptions and evaluations of what is not known. Then, we point out some of the institutional reactions to the political and cultural dynamics of scientific nonknowledge. We argue that the equal recognition of the diverse cultures of nonknowledge is a key prerequisite for socially legitimate and ‘‘robust’’ decision-making under conditions of politicised scientific nonknowledge. (shrink)

The “God of the gaps” critique is one of the most common arguments against design arguments in biology, but is also increasingly used as a critique of other natural theological arguments. In this paper, I analyze four different critiques of God of the gaps arguments and explore the relationship between gaps arguments and similar limit arguments. I conclude that the critique of the God of the gaps is substantially weaker than is commonly assumed, and dismissing ID´s biological arguments should rather (...) be based on criticizing the premises of these arguments. (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 paper applies two argumentation schemes, argument from fairness and argument from lack of knowledge (along with other schemes of lesser prominence) to model the reasoning given by Judge McCarthy supporting his decision to divide the proceeds of a homerun baseball in the case of Popov v. Hayashi. Several versions of both schemes are explained and discussed, and then applied to the argumentation given by Judge McCarthy as the basis of the reasoning used to arrive at his decision. The scheme (...) for argument from fairness is shown to be based on a special principle in Perelman’s theory of justice. (shrink)

This paper makes a case for a refined look at the so- called ‘fallacy of hasty generalization’ by arguing that this expression is an umbrella term for two fallacies already distinguished by Aristotle. One is the fallacy of generalizing in an inappropriate way from a particular instance to a universal generalization containing a ‘for all x’ quantification. The other is the secundum quid (‘in a certain respect’) fallacy of moving to a conclusion that is supposed to be a universal generalization (...) containing a ‘for all x‘ quantification while overlooking qualifications that have to be added to the more limited kind of generalization expressed in the premise. It is shown that these two fallacies relate to two different kinds of generalization. (shrink)

In this paper, the traditional view that argumentum ad ignorantiam is a logical fallacy is challenged, and lessons are drawn on how to model inferences drawn from knowledge in combination with ones drawn from lack of knowledge. Five defeasible rules for evaluating knowledge-based arguments that apply to inferences drawn under conditions of lack of knowledge are formulated. They are the veridicality rule, the consistency of knowledge rule, the closure of knowledge rule, the rule of refutation and the rule for argument (...) from ignorance. The basic thesis of the paper is that knowledge-based arguments, including the argument from ignorance, need to be evaluated by criteria for epistemic closure and other evidential rules that are pragmatic in nature, that need to be formulated and applied differently at different stages of an investigation or discussion. The paper helps us to understand practical criteria that should be used to evaluate all arguments based on knowledge and/or ignorance. (shrink)

In the article, referring to the method of rational reconstruction described by R. Rorty, an analysis of some works of J. Locke has been made in order to identify new prospects in John Locke's philosophy researches. As a result, it’s been demonstrated the presence of silence as an argument and a manifestation of respect J. Locke’s research of realms of cognition, political philosophy and philosophy of education. This is not covered in modern John Locke's philosophy researches. The authors emphasize that (...) J. Locke, although not directly exploring silence as an argument, however, describes the argument ad ignorantiam, the wording of which in the work «An Essay Concerning Human Understanding» and his understanding of tacit consent in the work «Two Treatises of Government» are related to silence as an argument and a manifestation of respect. The position that silence as an argument is present in all four arguments (argumentum ad verecundiam, argumentum ad ignorantiam, argumentum ad hominem, argumentum ad judicium) described by J. Locke is substantiated. Additionally, the argument ad ignorantiam can be considered both as an argument from silence (ex silentio argument) and as a kind of argument to silence. Considered arguments can serve as an argument to silence for the proponent and/or the third party, that is, anyone who is not directly involved in the dispute. Basing on J. Locke's explanation of the characteristic feature of tacit consent, that is, the absence of the expressed consent/disagreement, the possibility of distinguishing the indirect connection between tacit consent and the argument ad ignorantiam is demonstrated, since both tacit consent and the argument ad ignorantiam in J. Locke's works rely on the absence of expressed statements on the consent or disagreement of the opponent. It is established that the ideas of the education of children described by J. Locke also correlate with silence as an argument and a manifestation of respect. Applying the classification of the types of respect proposed by S. Hudson and complemented by R. Dillon to the use of the term «respect» to the various texts of J. Locke, it is substantiated that described by him respect covered almost all kinds of this classification. (shrink)

The purpose of this paper is twofold: to give a good account of the argument from ignorance, with a presumptive argumentation scheme, and to raise issues on the work of Walton, the nature of abduction and the concept of epistemic closure. First, I offer a brief disambiguation of how the terms 'argument from ignorance' and 'argumentum ad ignorantiam' are used. Second, I show how attempts to embellish this form of reasoning by Douglas Walton and A.J. Kreider have been unnecessary and (...) unhelpful. Lastly, I offer a full and effective account of the argument from ignorance and discuss the lessons of the analysis.Le but de cet article est double: donner un bon compte rendu de l'argument par l'ignorance, avec un schème d'argumentation présomptif, et soulever des questions sur certains aspects de l’œuvre de Walton, la nature des raisonnements abductifs et le concept de fermeture épistémique. Premièrement, j'offre une brève désambiguïsation de la façon dont les termes «argument par l'ignorance» et «argumentum ad ignorantiam» sont utilisés. Deuxièmement, je montre comment les tentatives de Douglas Walton et de A.J. Kreider d'embellir cette forme de raisonnement ont été ni nécessaires et ni utiles. Enfin, j'offre un compte-rendu complet et utile de l'argument par l'ignorance et je discute des leçons de l'analyse. (shrink)

This investigation uses the technique of the profile of dialogue as a tool for the evaluation of arguments from ignorance (also called lack-of-evidence arguments, negative evidence, ad ignorantiam arguments and ex silentio arguments). Such arguments have traditionally been classified as fallacies by the logic textbooks, but recent research has shown that in many cases they can be used reasonably. A profile of dialogue is a connected sequence of moves and countermoves in a conversational exchange of a type that is goal-directed (...) and can be represented in a normative model of dialogue. Selected case studies are used to probe special features of using the profile technique as applied to arguments from ignorance of a kind that occur frequently in everyday conversational exchanges. One of these special features is the use of Gricean implicature. Another is the need to use negative profiles of argument. (shrink)

Since published acknowledgements of scientific misconduct are a species of image restoration, common strategies for responding publicly to accusations can be expected: from sincere apologies to ritualistic apologies. This study is a rhetorical examination of these strategies as they are reflected in choices in language: it compares the published retractions and letters of apology with the letters that charge misconduct. The letters are examined for any shifts in language between the charge of misconduct and the response to the charge in (...) order to assess whether the apology was sincere or ritualistic. The results indicate that although most authors’ published acknowledgments of scientific misconduct seem to minimize culpability by means of the strategic use of language, their resulting ritualistic apologies often still satisfy in some way the accusers’ (and thus their community’s) concerns. (shrink)

In this paper, it is argued that Ferguson’s (2003, Argumentation 17, 335–346) recent proposal to reconcile monotonic logic with defeasibility has three counterintuitive consequences. First, the conclusions that can be derived from his new rule of inference are vacuous, a point that as already made against default logics when there are conflicting defaults. Second, his proposal requires a procedural “hack” to the break the symmetry between the disjuncts of the tautological conclusions to which his proposal leads. Third, Ferguson’s proposal amounts (...) to arguing that all everyday inferences are sound by definition. It is concluded that the informal logic response to defeasibility, that an account of the context in which inferences are sound or unsound is required, still stands. It is also observed that another possible response is given by Bayesian probability theory (Oaksford and Chater, in press, Bayesian Rationality: The Probabilistic Approach to Human Reasoning, Oxford University Press, Oxford, UK; Hahn and Oaksford, in press, Synthese). (shrink)

In Theory and Problems of Logic, Nolt et al. (1998, p. 203) claim that the following argument forms are fallacious: (a) It has not been proved that p. Therefore, ∼p. (b) It has not been proved that ∼p. Therefore, p. Accordingly, they argue that the following instances of (a) and (b) are also fallacious. (ai) No one has ever proved that God exists. Therefore, God does not exist. (bi) No one has ever proved that God does not exist. Therefore, God (...) exists. Nolt/Rohatyn/Varzi’s verdict on arguments from ignorance is acceptable: “Nothing about the existence of God follows from our inability to prove God’s existence or nonexistence (i.e., from our ignorance about the matter)” (p. 203). However, since their analysis glosses over the role played by our epistemic efforts, their example might lead one to believe that theism and atheism are in the same predicament. Nevertheless, as I am about to argue, the weakness of the known arguments in favor of the existence of God coupled with the existence of an asymmetry between positive and negative empirical existential propositions determines a presumption in favor of the atheist that Nolt/Rohatyn/Varzi’s sketchy analysis of arguments from ignorance obscures. (shrink)

Sanford Goldberg’s account of epistemic coverage constitutes a special case of Douglas Walton’s view that epistemic closure arises from dialectical argument. Walton’s pragmatic version of epistemic closure depends on dialectical norms for closing an argument, and epistemic coverage operates at the limits of argument closure because it minimizes dialectical exchange. Such closure works together with a shared hypothetical consideration to justify dismissal of surprising claims.

Absence of evidence arguments are indispensable to comparative neurobiology. The absence in a given species of a homologous neural architecture strongly correlated with a type of conscious experience in humans should be able to be taken as a prima facie reason for concluding that the species in question does not have the capacity for that conscious experience. Absence of evidence reasoning is, however, widely disparaged for being both logically illicit and unscientific. This paper argues that these concerns are unwarranted. There (...) is no logical barrier to formulating cogent absence of evidence arguments; indeed, accepting such arguments is part of what it is to be committed to falsifiability as a critical aspect of the scientific method. Absence of evidence arguments can always be blocked, however, by assuming that psychological properties are ‘multiply realizable’. While we take multiple realizability to be highly likely at some level of analysis, we argue that it is question-begging to assume that it exists at every level of analysis, and thus it should not automatically be thought to undermine absence of evidence reasoning in the animal consciousness debate. Using the example of pain and focusing on homologies at the level of information processing tasks, we show how, in the science of consciousness, an absence of evidence might well serve as evidence of absence. (shrink)

This dissertation argues that recent theoretical attempts to understand fallacious reasoning fail because these theories presuppose problematic accounts of the nature of argument. Current fallacy theories agree that a fallacy is a mistake, but differ wildly about what sort of mistake it is. Chapters one through three explore three very different suggestions. Chapter one is devoted to an examination of the oldest of the modern theoretical accounts of fallacious reasoning, what Hamblin calls the standard treatment. Chapter two begins with a (...) discussion of Finocchiaro's skeptical argument against the very possibility of a fallacy theory. It then turns to a discussion of van Eemeren and Grootendorst's pragma-dialectical treatment of fallacious reasoning as a possible response to Finocchiaro's skeptical challenge. Chapter three examines two epistemic responses to Finocchiaro's analysis: Fogelin and Duggan's frequency treatment and Wreen's mistaken inference treatment. The first three chapters set the stage for an alternative account of fallacies developed in chapter four. This alternative view of fallacious reasoning is consistent with Wright's recent work on the concept of an argument. It suggests that fallacious reasoning results from a kind of incompetency. Such failures of competency, however, are not nearly as common as traditional accounts of fallacious reasoning suggests. Moreover, the very possibility of being tempted by fallacious reasoning depends on our being very competent in normal cases. Chapter four ends with a discussion of some of the implications of this alternative theory of fallacious reasoning for the way we understand and teach argument and reasoning. (shrink)

This paper attempts to integrate an agnotological taxonomy of “not-knowing” with argumentation theory. Given rhetoric’s emphasis on what arguers choose to make present for their audience, it is argued that the rhetorical approach is best suited to accommodate the proposed taxonomy. In doing so we can improve the capacities of both arguers and audiences to detect adverse elements such as prejudices, implicit biases, and ideologies, which can restrict an argument’s claim to objectivity.