Philosophers of science have given up on the quest for a silver bullet to put an end to all pseudoscience, as such a neat formal criterion to separate good science from its contenders has proven elusive. In the literature on critical thinking and in some philosophical quarters, however, this search for silver bullets lives on in the taxonomies of fallacies. The attractive idea is to have a handy list of abstract definitions or argumentation schemes, on the basis of which one (...) can identify bad or invalid types of reasoning, abstracting away from the specific content and dialectical context. Such shortcuts for debunking arguments are tempting, but alas, the promise is hardly if ever fulfilled. Different strands of research on the pragmatics of argumentation, probabilistic reasoning and ecological rationality have shown that almost every known type of fallacy is a close neighbor to sound inferences or acceptable moves in a debate. Nonetheless, the kernel idea of a fallacy as an erroneous type of argument is still retained by most authors. We outline a destructive dilemma we refer to as the Fallacy Fork: on the one hand, if fallacies are construed as demonstrably invalid form of reasoning, then they have very limited applicability in real life. On the other hand, if our definitions of fallacies are sophisticated enough to capture real-life complexities, they can no longer be held up as an effective tool for discriminating good and bad forms of reasoning. As we bring our schematic “fallacies” in touch with reality, we seem to lose grip on normative questions. Even approaches that do not rely on argumentation schemes to identify fallacies fail to escape the Fallacy Fork, and run up against their own version of it. (shrink)

In this paper, we present a survey of the development of the technique of argument diagramming covering not only the fields in which it originated - informal logic, argumentation theory, evidence law and legal reasoning – but also more recent work in applying and developing it in computer science and artificial intelligence. Beginning with a simple example of an everyday argument, we present an analysis of it visualised as an argument diagram constructed using a software tool. In the context of (...) a brief history of the development of diagramming, it is then shown how argument diagrams have been used to analyze and work with argumentation in law, philosophy and artificial intelligence. (shrink)

Contrary to current individualistic epistemology, Classical rhetoric provides us with a pragmatical and particularly dynamic conception of ‘testimony’ as a source made available for the orator by the particular community in which she acts. In order to count as usable testimony, a testimony to which one could appeal in further communications, any discourse must comply with specific rules of social sanction. A deliberate attention to the social practices in which testimony is given and assessed may offer us a more accurate (...) view of its epistemological role. (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.

In a recent article in Argumentation, O’Keefe (Argumentation 21:151–163, 2007) observed that the well-known ‘framing effects’ in the social psychological literature on persuasion are akin to traditional fallacies of argumentation and reasoning and could be exploited for persuasive success in a way that conflicts with principles of responsible advocacy. Positively framed messages (“if you take aspirin, your heart will be more healthy”) differ in persuasive effect from negative frames (“if you do not take aspirin, your heart will be less healthy”), (...) despite containing ‘equivalent’ content. This poses a potential problem, because people might be unduly (and unsuspectingly) influenced by mere presentational differences. By drawing on recent cognitive psychological work on framing effects in choice and decision making paradigms, however, we show that establishing whether two arguments are substantively equivalent—and hence, whether there is any normative requirement for them to be equally persuasive—is a difficult task. Even arguments that are logically equivalent may not be information equivalent. The normative implications of this for both speakers and listeners are discussed. (shrink)

Perelman's work has been very influential in various disciplines, among them philosophy, rhetoric and law. Especially the typology of argumentative schemes which he developed together with L. Olbrechts-Tyteca has been considered as an excellent classification of arguments in natural language. There are, however, some weaknesses of this typology which make its application to empirical research quite difficult, namely, the lack of explicitness and the absence of clear criteria of demarcation. Still, the typology is highly relevant for empirical research, if these (...) weaknesses are removed. This is illustrated with an example: the scheme called ‘the division of the whole into its parts’ by Perelman/Olbrechts-Tyteca is described explicitly and then applied to the analysis of a sample of everyday arguments (mostly taken from newspapers). (shrink)

Needed for such dialogue games as dialectic are appropriate standards of fairness and rationality. The rules of procedure of dialectic must describe a game playable by actual human participants. The present paper centers on certain idealizations of the dialectician that are not allowable.

The paper analyses the role played by the concept of ‘common ground’ in argumentation theories. If a common agreement on all the rules of a discursive exchange is required, either at the beginning or at the end of an argumentative practice, then no violation of the rules is possible. The paper suggests an alternative understanding of ‘common ground’ as something that can change during the development of the argumentative practice, and in particular something that can change without the practice being (...) stopped, just as one sometimes violates the rule of a game without stopping playing. The analysis of some historical examples shows that the violation of rules sometimes leads to a consensual change of a set of beliefs and values. The argumentative rationality thus needs to be reconsidered in the light of the analysis of the conditions under which it would be legitimate to change the rules of an argumentative practice: ‘common ground’ and the right to disagreement, even radical or violent, could then be defended as essential components of argumentative rationality. (shrink)

An ad hominem fallacy is committed when an individual employs an irrelevant personal attack against an opponent instead of addressing that opponent’s argument. Many discussions of such fallacies discuss judgments of relevance about such personal attacks, and consider how we might distinguish those that are relevant from those that are not. This paper will argue that the literature on bias and testimony can helpfully contribute to that analysis. This will highlight ways in which biases, particularly unconscious biases, can make ad (...) hominem fallacies seem effective, even when the irrelevance is recognized. (shrink)

Informal logic is an attempt to develop a logic that can assess and analyze the arguments that occur in natural language discourse. Discussions in the field may address instances of scientific, legal, and other technical forms of reasoning, but the overriding aim has been a comprehensive account of argument that can explain and evaluate the arguments found in discussion, debate and disagreement as they manifest themselves in daily life — in social and political commentary; in news reports and editorials in (...) the mass media ; in advertising and corporate and governmental communications; and in personal exchange. (shrink)

Many public information documents attempt to persuade the recipients that they should engage in or refrain from specific behaviour. This is based on the assumption that the recipient will decide about his or her behaviour on the basis of the information given and a rational evaluation of the pros and cons. An analysis of 20 public information brochures shows that the argumentation in persuasive brochures is often not marked as such. Argumentation is presented as factual information, and in many instances (...) the task of making argumentational links and drawing conclusions is left to the reader. However, since the information offered does follow familiar argumentational schemes, readers can, in principle, reconstruct the argument. All the brochures make use of pragmatic argumentation (argumentation from consequences),i. e.,they formulate at least certain benefits of the desirable behaviour or disadvantages of the undesirable behaviour. In addition, they make regular use of argumentation from cause to effect and argumentation from example. Argumentation from rules and argumentation from authority are less frequently used. This empirical analysis of the use of argumentation schemes is a solid base for interesting and rich hypotheses about the cognitive processing of persuasive brochures. Central processing requires the reader to be able to reconstruct argumentation from informational texts and to identify and evaluate various types of argumentation. (shrink)

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

J. Anthony Blair is a prominent international figure in argumentation studies. He is among the originators of informal logic, an author of textbooks on the informal logic approach to argument analysis and evaluation and on critical thinking, and a founder and editor of the journal Informal Logic. Blair is widely recognized among the leaders in the field for contributing formative ideas to the argumentation literature of the last few decades. This selection of key works provides insights into the history of (...) the field of argumentation theory and various related disciplines. It illuminates the central debates and presents core ideas in four main areas: Critical Thinking, Informal Logic, Argument Theory and Logic, Dialectic and Rhetoric. (shrink)

In the pragma-dialectical approach, fallacies are considered incorrect moves in a discussion for which the goal is successful resolution of a dispute. Ten rules are given for effective conduct at the various stages of such a critical discussion (confrontation, opening, argumentation, concluding). Fallacies are discussed as violations of these rules, taking into account all speech acts which are traditionally recognized as fallacies. Special attention is paid to the role played by implicitness in fallacies in everyday language use. It is stressed (...) that identifying and acknowledging fallacies in ordinary discussions always has a conditional character. Differences between the pragma-dialectical perspective, the Standard Treatment, and the formal logic approach to fallacy analysis are discussed. (shrink)

This article evaluates the strengths and weaknesses of arguments based on appeals to expertise. The intersection of two areas is explored: (i) the traditional argumentum ad verecundiam (literally, “appeal to modesty,” but characteristically the appeal to the authority of expert judgment) in informal logic, and (ii) the uses of expert systems in artificial intelligence. The article identifies a model of practical reasoning that underlies the logic of expert systems and the model of argument appropriate for the informal logic of the (...) argumentum ad verecundiam. (shrink)

In recent and not so recent years, fallacy theory has sustained numerous challenges, challenges which have seen the theory charged with lack of systematicity as well as failure to deliver significant insights into its subject matter. In the following discussion, I argue that these criticisms are subordinate to a more fundamental criticism of fallacy theory, a criticism pertaining to the lack of intelligibility of this theory. The charge of unintelligibility against fallacy theory derives from a similar charge against philosophical theories (...) of truth and rationality developed by Hilary Putnam. I examine how Putnam develops this charge in the case of the conception of rationality pursued by logical positivism. Following that examination, I demonstrate the significance of this charge for how we proceed routinely to analyse one informal fallacy, the fallacy of petitio principii. Specifically, I argue that the significance of this charge lies in its issuance of a rejection of the urge to theorise in fallacy inquiry in general and petitio inquiry in particular. My conclusion takes the form of guidelines for the post-theoretical pursuit of fallacy inquiry. (shrink)

A Bibliography of Douglas Walton’s Published Works, 1971-20.

In this work it is argued that legal justification can best be studied from a procedural, dialogical point of view: legal statements are justified if the audience is convinced in an argumentative dialog. The formalized and implemented model DiaLaw guards the procedure in which two players aim at justifying statements. DiaLaw shows the advances and problems linked to procedural models of legal justification. Moreover, an instructive discussion of the different models of procedural justification is provided. It is stressed that in (...) legal justification not only logically compelling arguments should be considered, but also convincing arguments. Therefore DiaLaw also deals with the rhetorical, psychological aspects of argument. This book is relevant for scholars in legal theory, artificial intelligence, and argumentation, and can be used in graduate courses on AI and Law, and legal argumentation. (shrink)

In this paper, I examine the incessant call to theory that is evident in fallacy inquiry. I relate the motivations for this call to a desire to attain for fallacy inquiry certain attributes of the theoretical process in scientific inquiry. I argue that these same attributes, when pursued in the context of philosophical inquiry in general and fallacy inquiry in particular, lead to the assumption of a metaphysical standpoint. This standpoint, I contend, is generative of unintelligibility in philosophical discussions of (...) rationality. I claim that this same unintelligibility can be shown to characterise fallacy inquiry, an example of the study of argumentative rationality. The context for my claim is an examination of the theoretical pronouncements of two prominent fallacy theorists, John Woods and Douglas Walton, in relation to the argument from ignorance fallacy. My conclusion takes the form of guidelines for the post-theoretical pursuit of fallacy inquiry. (shrink)

This volume reflects the development and theoretical foundation of a new paradigm for critical thinking based on inquiry. The field of critical thinking, as manifested in the Informal Logic movement, developed primarily as a response to the inadequacies of formalism to represent actual argumentative practice and to provide useful argumentative skills to students. Because of this, the primary focus of the field has been on informal arguments rather than formal reasoning. Yet the formalist history of the field is still evident (...) in its emphasis, with respect to both theory and pedagogy, on the structure and evaluation of individual, de-contextualized arguments. It is our view that such a view of critical thinking is excessively narrow and limited, failing to provide an understanding of argumentation as largely a matter of comparative evaluation of a variety of contending positions and arguments with the goal of reaching a reasoned judgment on an issue. As a consequence, traditional critical thinking instruction is problematic in failing to provide the reasoning skills that students need in order to accomplish this goal. Instead, the goal of critical thinking instruction has been seen largely as a defensive one: of learning to not fall prey to invalid, inadequate, or fallacious arguments. (shrink)

Consider the proposition, "Informal logic is a subdiscipline of philosophy". The best chance of showing this to be true is showing that informal logic is part of logic, which in turn is a part of philosophy. Part 1 is given over to the task of sorting out these connections. If successful, informal logic can indeed be seen as part of philosophy; but there is no question of an exclusive relationship. Part 2 is a critical appraisal of the suggestion that informal (...) logic is applied epistemology. Part 3 examines the claim that informal logic has failed to penetrate into mainstream philosophy, and suggestions for amelioration are considered. (shrink)

In Fallacies and Judgments of Reasonableness, Frans H. van Eemeren, Bart Garssen and Bert Meuffels report on their systematic empirical research of the conventional validity of the pragma-dialectical discussion rules. The experimental studies they carried out during more than ten years start from the pragma-dialectical theory of argumentation developed at the University of Amsterdam, their home university. In these studies they test methodically the intersubjective acceptability of the rules for critical discussion proposed in this theory by confronting ordinary arguers who (...) have not received any special education in argumentation and fallacies with discussion fragments containing both fallacious and non-fallacious argumentative moves. The research covers a wide range of informal fallacies. In this way, the authors create a basis for comparing the theoretical reasonableness conception of pragma-dialectics with the norms for judging argumentative moves prevailing in argumentative practice. Fallacies and Judgments of Reasonableness provides a unique insight into the relationship between theoretical and practical conceptions of reasonableness, supported by extensive empirical material gained by means of sophisticated experimental research. (shrink)

Authority arguments generate support for claims by appealing to an agent’s authority status, rather than to reasons independent of it. With few exceptions, the current literature on argument schemes acknowledges two basic authority types. The _epistemic_ type grounds in knowledge, the_ deontic_ type grounds in power. We review how historically earlier scholarship acknowledged an_ attractiveness-based_ and a _majority-based_ authority type as equally basic type. Crossing these with basic speech act types thus yields authority argument sub-schemes. Focusing on the_ epistemic-assertive_ sub-scheme (...) (‘an epistemic authority _A_ _E_ asserts a proposition _P_’), we apply a meta-level approach to specifying critical questions. Results improve the evaluation of this sub-scheme and show how similar improvements are obtainable for other schemes. (shrink)

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

Defeasible reasoning is concerned with the logics of non-deductive argument. As is described in the literature, the study of this type of reasoning is considerably more involved than the study of deductive argument, even so that, in realistic applications, there is often a lack of resources to perform an exhaustive analysis. It follows that, in a theory of defeasible reasoning, the order and direction in which arguments are developed, i.e. theprocedure, is important. The aim of this article is to show (...) that debate is the most efficient procedure to argue in the presence of limited resources. To do so, there is first some general theory on defeasible argumentation, which is followed by an introduction to the problem of dialectical search. The problem of dialectical search is (or at least, should be) the essential issue in every theory on argumentation, and emerges at every occasion that involves adjudication on competing arguments. Starting with an example, it is explained that dialectical search can be best scheduled according to classical debating techniques, that work along well-tried methods. These methods (which include various forms of curtailment, interruption, and interpretation) have proven their value in keeping debating efforts within reasonable bounds. How they apply in a theory of formal argument, will be shown in this article. (shrink)

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

Some current attempts to go beyond the narrow scope of rational choice theory (RCT) in the social sciences and the artificial reconstructions it sometimes provides focus on the arguments that people give to justify their beliefs and behaviors themselves. But the available argumentation theories are not constructed to fill this gap. This article argues that relevance theory, on the contrary, suggests interesting tracks. This provocative idea requires a rereading of Sperber and Wilson's theory. Actually, the authors do not explicitly support (...) RCT, and Sperber has even strongly criticized methodological individualism, which most of the time underlies RCT, in favor of infra-individualism. A key point of the argument presented here is to show that Sperber and Wilson do not firmly distinguish between infra-individualism and subintentionality. Only subintentionality is needed. Key Words: argumentation • rational choice • relevance theory • methodological individualism. (shrink)

The research discussed in this paper concerns an investigation of logical dialogue games as a vehicle for enhanced human-computer communication. The need for a dialogue capability in computer systems is argued, and a prima facie case made for dialogue games, in particular Mackenzie's "DC", as a suitable dialogue model. Empirical work concerning DC is outlined, and strategies for adoption by the computer are presented. A user interface, software architecture and conceptualised example are discussed. The hope is that the paper will (...) help bring together two groups of workers-philosophers of dialogue and designers of computer systems-to the mutual benefit of each. (shrink)

This paper surveys the contributions to the study of argumentation in the two decades since the work of Toulmin and Perelman. Developments include Radical Argumentativism (Anscombre and Ducot), Communication and Rhetoric (American Speech Communication Theory), Informal Logic (Johnson and Blair), Formal Analyses of Fallacies (Woods and Walton), Formal Dialectics (Barth and Krabbe), and Pragma-Dialectics (van Eemeren and Grootendorst). From the survey it is concluded that argumentation theory has been considerably enriched. If the contributions can be made to converge, a sound (...) basis will be created for developing educational methods for producing, interpreting and evaluating argumentative discourse. Thus, argumentation theory may be instrumental in improving the quality of democracy by furthering a reasonable management of differences of opinion. (shrink)

How do Dutch people let each other know that they disagree? What do they say when they want to resolve their difference of opinion by way of an argumentative discussion? In what way do they convey that they are convinced by each other’s argumentation? How do they criticize each other’s argumentative moves? Which words and expressions do they use in these endeavors? By answering these questions this short essay provides a brief inventory of the language of argumentation in Dutch.

Woods and Walton deserve credit for including a discussion of “economic reasoning” and its susceptibility to the “fallacy of composition.” Unfortunately, they did not sufficiently pursue the topic, and argumentation scholars have apparently ignored their pioneering effort. Yet, obviously, economic argumentation is extremely important, and economists constantly harp on this fallacy. This paper calls attention to this problem, elaborating my own approach, which is empirical, historical, and meta-argumentational.