Informal Logic

Mercier and Sperber (2011a, 2011b; Mercier, 2011a, 2011b, 2011c, and 2011d) have presented a stimulating and provocative new theory of reasoning: the argumentative theory of reasoning. They maintain that argumentation is a meta-representational module. In their evolutionary view of argumentation, the function of this module would be to regulate the flow of information between interlocutors through persuasiveness on the side of the communicator and epistemic vigilance on the side of the audience. The aim of this paper is to discuss the perspective of the authors in which they conceive this competence as the natural scenario of reflective reasoning.

Toulmin's formulation of analytic arguments' in his 1958 book, The Uses of Argument, is opaque. Commentators have not adequately explicated this formulation, though Toulmin called it a key' and crucial' concept for his model of argument macrostructure. Toulmin's principle tests' for determining analytic arguments are problematic. Neither the tautology test' nor the verification test' straightforwardly indicates whether an argument is analytic or not. As such, Toulmin's notion of analytic arguments might not represent such a key feature of his model. Absent a clearer formulation of analytic arguments, readers of Toulmin should be hesitant to adopt this terminology.

I will show that there is a type of analogical reasoning that instantiates a pattern of reasoning in confirmation theory that is considered at best paradoxical and at worst fatal to the entire syntactical approach to confirmation and explanation. However, I hope to elaborate conditions under which this is a sound (although not necessarily strong) method of reasoning.

In this essay I propose an interpretative and explanatory structure for the so-called argumentum ex silento, or argument from silence (henceforth referred to as the AFS). To this end, I explore two examples, namely, Sherlock Holmes's oft-quoted notice of the curious incident of the dog in the night-time' from Arthur Conan Doyle's short story Silver Blaze,' and the historical question of Paul of Tarsus's silence on biographical details of the historical Jesus. Through these cases, I conclude that the AFS serves as a dialogical topos best evaluated and understood through the perceived authority of the arguer and the willingness of the audience to accept that authority, due to the curious' nature of the negative evidence that the argument employed.

In a recent paper in this journal, David Botting defended pragma-dialectics against epistemological criticisms by exponents of the epistemological approach to argumentation, i.e. Harvey Siegel, John Biro and me. In particular, Botting tries to justify with new arguments a Functional Claim, that the function of argumentation is to resolve disputes, and a Normative Claim, that standpoints that have the unqualified consensus of all participants in a dispute will generally be epistemically sound. In this reply it is shown that Botting's arguments are fallacious, that the two Claims are false and that the epistemological approach to argumentation, of course, outclasses pragma-dialectics epistemically and is at least as good as it in other respects.

The study of threat and fear appeal arguments has given rise to a sizeable literature. Even within a public health context, much is now known about how these arguments work to gain the public's compliance with health recommendations. Notwithstanding this level of interest in, and examination of, these arguments, there is one aspect of these arguments that still remains unexplored. That aspect concerns the heuristic function of these arguments within our thinking about public health problems. Specifically, it is argued that threat and fear appeal arguments serve as valuable shortcuts in our reasoning, particularly when that reasoning is subject to biases that are likely to diminish the effectiveness of public health messages. To this extent, they are rationally warranted argument forms rather than fallacies, as has been their dominant characterization in logic.

Following a Toulmian account of argument analysis and evaluation, I offer a general unitary schema for, so called, deductive and inductive types of analogical arguments. This schema is able to explain why certain analogical arguments can be said to be deductive, and yet, also defeasible.

It is unfortunate that Hamblin's contributions do not get him the credit he deserves for his remarkable achievements. Although his contributions to philosophy are well enough recognized, and his early contributions to computing have been acknowledged, it seems strange that his work has not been widely enough recognized for the interdisciplinary effect it has had. There has been a feedback loop whereby his theories on formal dialogue systems and imperatives were taken up in argumentation, applied in computing, and then used in this form to refine argumentation methods.

This paper aims at a normative account of non-deductive argumentation schemes in the spirit of Hamblin's dialectical philosophy. First, three principles are presented that characterize Hamblin's dialectical stance. Second, argumentation schemes, which have hardly been examined in Hamblin's book Fallacies, shall be dealt with by applying these principles, taking an argumentation scheme from authority as the leading example. Third, a formal dialectical system, along the lines indicated by Hamblin, shall be developed that includes norms for using argumentation schemes and norms for responding to arguments that are presented as instantiating acceptable argumentation schemes.

When we use a word, we face a crucial epistemic gap: we ground our move on the fact that our interlocutor knows the meaning of the word we used, and therefore he can interpret our dialogical intention. However, how is it possible to know the other's mind? Hamblin explained this dialogical problem advancing the idea of dialectical meaning: on his view, the use of a word is based on a set of presumptions. Building on this approach, the use of a word in a dialogue can be analyzed in terms of presumptive reasoning, while the manipulative strategies based on slanted or loaded terms or redefinitions can be conceived as forms of conflicts of presumptions. A presumptive approach to meaning can also ground different dialectical strategies to solve misunderstanding or definitional disagreements, or tactics to undermine the interlocutor's arguments by advancing charges of equivocation.

There are passages in Fallacies suggesting a skeptical attitude to the very idea of inductive arguments, hence to the existence of inductive fallacies. Although the passages are brief and few in number, it would appear that Hamblin's resistance stems from doubts about the existence of relations of inductive consequence. This paper attempts to find a case in which such skepticism might plausibly be grounded. The case it proposes is highly conjectural, but important if true. Its greater importance lies in the threat it creates for the whole class of nonmonotonic logics.

Hamblin's Fallacies remains one of the crucial documents in the development of informal logic and argumentation theory. His critique of traditional approaches to the fallacies (what he dubbed ˜The Standard Treatment') helped to revitalize the study of fallacies. Recently I had occasion to reread Fallacies and came to the conclusion that some of my earlier criticisms (1989, 1990) had missed the real force of what was going on there, that I and others have perhaps not fully appreciated what Hamblin is up to. In this paper, I plan to revisit Fallacies and make manifest its coherence.

In his book on fallacies, Hamblin built a very simple system for argumentation in dialogue he called the Why Because System with Questions. In his discussion of this system, he replaced the concept of burden of proof with a simpler concept of initiative, which could be described as something like getting the upper hand as the argumentation moves back and forth in the dialogue between the one party and the other. No doubt he realized that the concept of burden of proof was too complex a matter to be dealt with in the limited scope of his chapter on formal dialogue systems. In this paper is shown how an extended version of Hamblin's dialogue system provides a nice way of modeling the phenomenon of shifting of burden of proof in a dialogue, yielding a precise way of distinguishing between different kinds of burden of proof, and dealing with fallacies like the argumentum ad ignorantiam (argument from negative evidence).

I finished my undergraduate degree at Monash University and joined Charles Hamblin's seminar at the University of NSW in March, 1968. Phil Staines from the University of Newcastle joined at the same time, and Vic Dudman was an established member. Hamblin's book Fallacies would be published in 1970, but the seminar discussions rarely concerned fallacies. This may have been because Hamblin had been working for so long and so closely with those ideas that he was now ready to turn elsewhere. But I shall argue that the book was only part of a much broader program, other parts of which occupied us in the seminars. Hamblin never explicitly discussed the writing of Fallacies with me, and what follows is an attempt to explain how the book fitted into his overall project as a logician, drawn from his published works and from what I remember of his contributions to the seminar.

In recent discussions concerning the definition of argument, it has been maintained that the word ˜argument' exhibits the process-product ambiguity, or an act/object ambigu-ity. Drawing on literature on lexical ambiguity we argue that ˜argument' is not ambiguous. The term ˜argu-ment' refers to an object, not to a speech act. We also examine some of the important implications of our argument by considering the question: what sort of abstract objects are arguments?

A conclusion follows from given premisses if and only if an acceptable counterfactual-supporting covering generalization of the argument rules out, either definitively or with some modal qualification, simultaneous acceptability of the premisses and non-accepta-bility of the conclusion, even though it does not rule out acceptability of the premisses and does not require acceptability of the conclusion independently of the premisses. Hence the reiterative associated conditional of an argument is true if and only it has such a covering generalization, and a supposed unexpressed premiss supplied to make an argument formally valid should be a covering generalization.

Reasonable hostility' is a norm of communicative conduct initially developed by studying public exchanges in education governance meetings in local U.S. communities. In this paper I consider the norm's usefulness for and applicability to a U.S. state-level public hearing about a bill to legalize civil unions. Following an explication of reasonable hostility and grounded practical theory, the approach to inquiry that guides my work, I de-scribe Hawaii's 2009, 18-hour pub-lic hearing and analyze selected segments of it. I show that this par-ticular public hearing raised de-mands for testifiers on the anti-civil union side of the argument that rea-sonable hostility does not do a good job of addressing. Development of a norm of communication conduct for this practice, as well as others, must engage with the culture and time-specific beliefs that a society holds, beliefs that will shape not only how to argue but what may be argued and what must be assumed about particular categories of persons.

This article challenges the common view that improvements in critical thinking are best pursued by investigations in informal logic. From the perspective of research in psychology and neuroscience, hu-man inference is a process that is multimodal, parallel, and often emo-tional, which makes it unlike the linguistic, serial, and narrowly cog-nitive structure of arguments. At-tempts to improve inferential prac-tice need to consider psychological error tendencies, which are patterns of thinking that are natural for peo-ple but frequently lead to mistakes in judgment. This article discusses two important but neglected error ten-dencies: motivated inference and fear-driven inference.

Arguments with what are called "independent" or "convergent" premises are typically diagrammed by using an arrow between each premise and the conclusion. This makes diagramming objections to the reasoning difficult. It also obscures differences in argument structure. I suggest that a single arrow should be used for such arguments and that this is so even in the extreme form of independent premises when the argument is entirely unstructured. I then discuss the diagramming of objections.

In her 2007 book "Epistemic Injustice" Miranda Fricker argues that "the silent by products of residual prejudice in a liberal society" are often the most difficult biases to eradicate. In this essay, I provide several examples of the kind of residual prejudice Fricker describes. I then propose a principle of "intellectual empathy" (with four component elements) as a methodological remedy for eradicating this kind of bias in good critical thinking.

Safe Safety arguments are key components in a safety case. Too often, safety arguments are constructed without proper reasoning. To address this, we argue that informal logic argument schemes have important roles to play in safety argument construction and reviewing process. Ten commonly used reasoning schemes in computer system safety domain are proposed. The role of informal logic dialogue games in computer system safety arguments reviewing is also discussed and the intended work in this area is proposed. It is anticipated that this work will contribute toward the development of computer system safety arguments, and help to move forward the interplay between research in informal logic and research in computer system safety engineering.

The product/process distinction with regards to argument' has a longstanding history and foundational role in argumentation theory. I shall argue that, regardless of one's chosen ontology of arguments, arguments are not the product of some process of arguing. Hence, appeal to the distinction is distorting the very organizational foundations of argumentation theory and should be abandoned.

    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.

Manipulation of quotation, shown to be a common tactic of argumentation in this paper, is associated with fallacies like wrenching from context, hasty generalization, equivocation, accent, the straw man fallacy, and ad hominem arguments. Several examples are presented from everyday speech, legislative debates and trials. Analysis using dialog models explains the critical defects of argumentation illustrated in each of the examples. In the formal dialog system CB, a proponent and respondent take turns in making moves in an orderly goal-directed sequence of argumentation in which the proponent tries to persuade the respondent to become committed to a conclusion by asking questions and offering arguments. Analyzing quotation by using the notion of commitment in dialog, it is shown (a) how an arguer's previous assertions can be brought to light in the course of a dialog to deal with problems arising from misquotation, (b) how the profile of dialog model allows a critic to analyse the fundamental effects misquotation brings about in a dialog, and (c) how the critic can use such an analysis to correct the problem.

In her 2007 paper, Argument Has No Function' Jean Goodwin takes exception with what she calls the explicit function claims', arguing that not only are function-based accounts of argumentation insufficiently motivated, but they fail to ground claims to normativity. In this paper I stake out the beginnings of a functionalist answer to Goodwin.

         Arguments commonly used in discussions about design, planning, policy-making issues have not been adequately analyzed in the literature. The structure of such ˜planning arguments' is discussed. Based on the conceptual framework of the ˜argumentative model of planning' proposed by H. Rittel, an approach for their systematic and transparent evaluation by discourse participants is presented. Procedural implications for its application in the planning process are discussed, and the potential for information technology support for such processes explored. 

I mention the benefits, challenges, and costs of using small group activities to enhance our students' learning of critical thinking skills in our courses, and then describe ten examples of these groups. Two of these examples are not commonly reported in the literature on small groups, so I describe them in greater detail to facilitate their use in our courses.

Garssen and van Laar in effect concede our main criticism of the pragma-dialectical approach. The criticism is that the conclusions of arguments can be ˜P-D reasonable' yet patently unreasonable, epistemically speaking. The concession consists in the claim that the theory remains restricted to the investigation of standpoints in the light of particular sets of starting points' which are up to individual disputants to create' and the admission that all the relevant terms of normative appraisal have been redefined. We also discuss their criticisms of the epistemic account of argumentation and argument evaluation and raise some new questions about the approach they defend.

In this paper, I argue that ad hominem arguments are not always fallacious. More explicitly, in certain cases of practical reasoning, the circumstances of a person are relevant to whether or not the conclusion should be accepted. This occurs, I suggest, when a person gives advice to others or prescribes certain courses of action but fails to follow her own advice or act in accordance with her own prescriptions. This is not an instance of a fallacious tu quoque provided that such circumstantial ad hominem arguments are construed as rebuttals to appeals to (administrative) authority (of expertise), or so I argue.

The problem with the pragma-dialectical view, it has been argued, is that it takes argumentation as aiming at consensus rather than truth or justified belief. The pragma-dialecticians often imply that an argumentative process aiming at consensus in a way constrained by the Ten Commandments' will in the long run converge on epistemically favourable standpoints. I will argue that they are right provided (i) pragma-dialectics is construed, as they say, as a theory of criticism; (ii) pragma-dialectics and the other theories of argumentation have in common the requirement to account for the fallacies. 

The recent literature on ad hominem argument contends that the speaker's character is sometimes relevant to evaluating what she says. This effort to redeem ad hominems requires an analysis of character that explains why and how character is relevant. I argue that virtue epistemology supplies this analysis. Three sorts of ad hominems that attack the speaker's intellectual character are legitimate. They attack a speaker's: (1) possession of reliabilist vices; or (2) possession of responsibilist vices; or (3) failure to perform intellectually virtuous acts. Legitimate ad hominems conclude that we should not believe what a speaker says solely on her say-so. 

    I define and refine Habermas's notion of systematically distorted communication by means of focused, structured comparison among three of its instances. Next, I show that its critique is possible within the confines of his theory by recourse to a minimalist concept of rationality and a version of the truth that avoids the unwelcome metaphysical baggage of truth with a capital T. For critique to be complete, however, it must be supplemented by the full range of rhetorical proofs. Even so, there are limits to the power of critique. In the end, only social and political action can alter oppressive institutional arrangements.   

 In the process of challenging epistemological assumptions that preclude relationships between knowers and the objects of knowing, feminist epistemologists Lorraine Code and Donna Haraway also can be interpreted as troubling forms of argumentation predicated on positivist-derived logic. Against the latter, Christopher Tindale promotes a rhetorical model of argument that appears able to better engage epistemologies of situated knowledges. I detail key features of the latter from Code, especially, and compare and contrast them with relevant parts of Tindale's discussion of context on the rhetorical model, and I suggest ways that his work could be expanded to accommodate rhetorical implications of situated knowledges.   

 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. 

The aim of this paper is to adapt Miranda Fricker's concept of testimonial injustice to cases of what I call argumentative injustice': those cases where an arguer's social identity brings listeners to place too much or little credibility in an argument. My recommendation is to adopt a stance of metadistrust''we ought to dis-trust our inclinations to trust or dis-trust members of stereotyped groups.

 This essay argues that ideals of cooperation or adversariality in argumentation are not equally attainable for women. Women in argumentation contexts face oppress-sive limitations undermining argument success because their authority is un-dermined by gendered norms of po-liteness. Women endorsing or, alter-natively, transgressing feminine norms of politeness typically defend their au-thority in argumentation contexts. And yet, defending authority renders it less legitimate. My argument focuses on women in philosophy but bears the implication that other masculine dis-course contexts present similar double binds that urge social and political change. 

 Philosophy's adversarial argumentation style is often noted as a factor contributing to the low numbers of women in philosophy. I argue that there is a level of adversariality peculiar to philosophy that merits specific feminist examination, yet doesn't assume controversial gender differences claims. The dominance of the argument-as-war metaphor is not warranted, since this metaphor misconstrues the epistemic role of good argument as a tool of rational persuasion. This metaphor is entangled with the persisting narrative of embattled reason, which, in turn, is linked to the sexism-informed narrative of the man of reason' continually warding off or battling feminine' unreason. 

 This special issue of Informal Logic brings together two important areas of philosophy that have shown significant development in the last three decades: informal logic and feminist philosophy. A significant innovation they both share is new thinking about practices of argumentation and related practices of reasoning. Feminist theorizing supporting social and political change foregrounds reasoning for change' in a way that draws attention to the contextual and rhetorical dimensions of argument and thus connects with significant developments in informal logic.  

 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 informal fallacies. 

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.

 We are all familiar with the traditional conception of what makes for a good argument: that its premises are true and that it is valid.[1] That traditional view of the goodness of arguments has sustained serious criticism over the past few decades, so that most theorists have dropped either the validity requirement or the truth requirement or both. Almost all theorists that I am aware of take it that an argument is good if it fulfills its purpose, and it is widely agreed that arguments can fulfill their purpose even when not all of their premises are true, or they are not deductively valid. Still, some theorists retain a focus on the truth-directed nature of arguments, and those theorists rightly hold that, given such a focus, truth plays an important role in the evaluation of arguments. Johnson (2000) goes so far as to reintroduce truth as a constraint on premise adequacy, alongside the criterion of acceptability, and he holds that in a case where a premise is false but acceptable, truth (/falsity) outweighs acceptability.             What I propose to do in this essay is to discuss the role that truth plays in the evaluation of arguments, when the purpose of arguments is understood as truth-directed in some important way. I begin with a discussion of truth and the purpose of arguments. In the second section of the paper, I give an argument to the effect that the theory of argument evaluation ought not to involve truth as a constraint on premise adequacy. The third section contains my argument for the positive claim that the proper place for the concept of truth is in the metatheory in terms of which the theory of evaluation is worked out.[2] I conclude the essay with a response to Hamblin's (1970) argument that no arguments are truth-directed.  [1] Hitchcock (1999) traces the concept of soundness in the textbook tradition to Black (1946), and before that (but with different terminology), to Cohen and Nagel (1934). [2] By "theory of evaluation" I mean the set of criteria that a theory provides us with for evaluating arguments. By "the metatheory" in terms of which the theory of evaluation is worked out, I mean the broader theory of argument, including reference to what it is that the criteria for argument evaluation are supposed to accomplish, in which the theory of evaluation is articulated. 

The epistemologists Biro and Siegel have raised two objections against the pragma-dialectical approach to argumentation. According to the first objection the pragma-dialectical theory is not genuinely normative. According to the second objection the rejection of justificationism by pragma-dialecticians is unwarranted: they reject justificationism prematurely and they are not consistent in accepting some arguments (˜justifications') as sound. The first objection is based on what we regard as the misconception that the goal of resolving differences of opinion cannot provide a normative approach. In response to the second objection we argue that in pragma-dialectics, the notion of argument, and related notions, are defined in a non-justificatory manner.

This paper analyzes and evaluates the 2007 majority opinion of the German National Ethics Council which seeks to establish new information (as to the inferior quality of legally procurable human embryonic stem cells) as a sufficient reason for a relaxation of the 2002 Stem Cell Law. A micro-level analysis of the opinion's central section is conducted and evaluated vis à vis the strongest known opponent position in the national debate at that time. The argumentation is claimed to rely on an unsupported semantic assumption regarding the parthood relation of the 2002 compromise and to misconstrue the strongest known opponent position. 

: Argument and explanation are distinct forms of reasoning with an underappreciated complementary relationship. In this essay I define these terms precisely, identify the mischief that results from conflating them, elucidate their complementary relationship and employ this relationship to provide a fruitful approach to analyzing the logical structure of the common editorial. Keywords: argument, evidence, explanation, cause, complementarity, editorial.

We contend that it is possible to argue reasonably for and against arguments from classifications and definitions, provided they are seen as defeasible (subject to exceptions and critical questioning). Arguments from classification of the most common sorts are shown to be based on defeasible reasoning of various kinds represented by patterns of logical reasoning called defeasible argumentation schemes. We show how such schemes can be identified with heuristics, or short-cut solutions to a problem. We examine a variety of arguments of this sort, including argument from abductive classification, argument from causal classification, argument from analogy-based classification and arguments from classification based on generalizations.