This paper presents a dialogue system called Lorenzen–Hamblin Natural Dialogue (LHND), in which participants can commit formal fallacies and have a method of both identifying and withdrawing formal fallacies. It therefore provides a tool for the dialectical evaluation of force of argument when players advance reasons which are deductively incorrect. The system is inspired by Hamblin’s formal dialectic and Lorenzen’s dialogical logic. It offers uniform protocols for Hamblin’s and Lorenzen’s dialogues and adds a protocol for (...) embedding them. This unification required a reformulation of the original description of Lorenzen’s system to distinguish “between different stances that a person might take in the discussion”, as suggested by Hodges. The LHND system is compared to Walton and Krabbe’s Complex Persuasion Dialogue using an example of a dialogue. (shrink)

: According to Kant, the arguments of rational psychology are formal fallacies that he calls transcendental paralogisms. It remains heavily debated whether there actually is any formal error in the inferences Kant presents: according to Grier and Allison, they are deductively invalid syllogisms, whereas Bennett, Ameriks, and Van Cleve deny that they are formal fallacies. I advance an interpretation that reconciles these extremes: transcendental paralogisms are sound in general logic but constitute formal fallacies (...) in transcendental logic. By formalising the paralogistic inference, I will pinpoint the error as an illegitimate existential presupposition. Since - unlike transcendental logic - general logic abstracts from all objects, this error can only be detected in transcendental logic. (shrink)

This note comments on the paper ‘Dialogue protocols for formal fallacies’ by Kacprzak and Yaskorska (this issue). Points discussed include the use of the notions of ‘claiming’, ‘conceding’ and ‘commitment’, and the role of Lorenzen dialogues as a device for checking whether a proposition is a tautology.

The taxonomy and analysis of fallacies in Aristotle's Sophistical Refutations pre-date the formal logic of his Prior Analytics A4-6. Of the 64 fully described examples of ?sophistical refutations? which are fallacious because they are only apparently valid, 49 have the wrong number of premisses or the wrong form of premiss or conclusion for analysis by the Prior Analytics theory of the categorical syllogism. The rest Aristotle either frames so that they do not look like categorical syllogisms or analyses (...) in a quite different way than by categorical syllogistic. (shrink)

Since its inception in the work on fallacies of Charles Hamblin, formal dialectic has been the object of an unparalleled level of optimism concerning the potential of its analytical contribution to fallacy inquiry. This optimism has taken the form of a rapid proliferation of formal dialectical studies of arguments in general and fallacious arguments in particular under the auspices of theorists such as Jim Mackenzie and John Woods and Douglas Walton, to name but a few. Notwithstanding the (...) interest in, and the hopes for, a formal dialectical analysis of the fallacies, such an analysis, I will demonstrate subsequently, leads to much unintelligibility in fallacy inquiry. The context of my argument will be the philosophical views of Hilary Putnam, particularly Putnam's claim that when we theorise in relation to rationality, the unintelligibility of the conception of rationality to emerge from this theoretical process can be traced to the circumscription of rationality within this theoretical process. I charge formal dialectic with effecting a similar circumscription of argumentative rationality, a circumscription that, I will claim, is generative of unintelligibility in formal dialectical analyses of the fallacies. In this case, the context for my claims will be the formal dialectical analyses of Walton and Batten, Rescher, Hamblin, Mackenzie and Hintikka, primarily in relation to the petitio principii fallacy. My conclusion examines a number of the reasons, both historical and conceptual, which have made it seem that it is possible to fully circumscribe the notion of argumentative rationality. (shrink)

세상에는 대부분 사람들이 믿는 통념이지만 실은 근거 없는 그런 견해도 있다. 우리나라 역사에 대해서도 근거 없이 믿고 있는 잘못된 신념들이 있다. 철학자인 나로서는 그런 신념을 만나면 먼저 개념(용법)분석을 시도한다. 분석 도구는 수학(연립방정식의 결정-과소결정(부정)-과잉결정(불능)), 자연과학(가설연역방법), 논리학(모순관계, 포함관계) 이다. 분석한 개념은 “주(炷: 심지)”와 “산(蒜: 달래)”, 단군의 “수(壽)”, 주몽의 아버지인 “해모수”와 “단군”의 용법, “해모수”의 세 가지 용법, “신기대보(神器大寶)” 등이다. 이 개념들을 분석해 보면 고대 한국 왕들이 장생불사(長生不死)의 철학을 믿었다는 것을 알 수 있다. 역사기록에 등장하는 용어를 그 당대 용법으로 이해하려면 엄격한 학문연구방법이 필요하다. 역사를 (...) 연구할 때 좀 더 치밀한 연구방법을 고민해야 한다. (shrink)

The argument given by Peter van Inwagen for the second premise on his "First Formal Argument" in An Essay on Free Will is invalid. The second premise hinges on the principle that since a proposition p , some statement about the present, is actually true, ~p can't be true. ~p must be false. What is the reason? The principle is that ~p cannot be true at the same time as p . I argue that, among other things, in its (...) attachment to this sort of principle, van Inwagen's argument commits the most familiar of all the modal scope fallacies. (shrink)

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

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)

This work is a revision of the False Dilemma Fallacy (FDF). The formalized model (FM)of this fallacy has as its centerpiece a valid disjunctive syllogism, but the disjunctive premise is presumed to be false, thus making the argument unsound. Our revised model (FM2.0) focuses on the formal structure by comparing the given vs. the real argument, which is unsound because of its invalidity. This approach we believe is more pedagogically useful and a better explanation of the fallacious nature of (...) the FDF. It extends the identity of “formal fallacy” to the FDF. The abstract is formatted in two columns. The English abstract goes on this side. (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)

This chapter focuses on one of the common fallacies in Western philosophy called 'naturalistic fallacy'. The naturalistic fallacy follows from one's metaphysical (metaethical) commitments rather than simply a general defect of reasoning. Unlike many fallacies – formal or informal – it is not likely that one will find the naturalistic fallacy in standard logic textbooks. The natural properties (e.g., pleasure) are logically and/or metaphysically distinct from normative or moral properties (e.g., goodness) and, thus, any identification of a (...) natural property with a normative property would be defective. G.E. Moore's metaphysics of values (metaethics) disallows any movement from natural to non‐natural properties. He thinks of normative properties/objects as logically and metaphysically distinct from non‐natural properties/objects. Yet if one rejects the wider non‐naturalistic moral realism central to Moore's naturalistic fallacy, it seems possible to accept a movement from the natural to normative. (shrink)

This chapter focuses on one of the common fallacies in Western philosophy, 'existential fallacy'. This fallacy occurs when we erroneously suppose some class or group has members. In other words, statements may be true about classes or groups even if no members of the class or group exist. In terms of syllogistic argumentation, this is a formal fallacy in that it results when the premises are universal in quantification and the conclusion is particular. In the history of logic, (...) the existential fallacy may be traced to dictum de omni, which refers to the principle in Aristotelian logic that whatever is said universally of a subject is said of everything that is contained under such a subject. In order to avoid this fallacy, one should look for empirical verification of the existence of whatever entity may be in question. (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)

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)

We are happy to present to the reader the first book of our Applied Logic Series. Walton's book on the fallacies of ambiguity is firmly at the heart of practical reasoning, an important part of applied logic. There is an increasing interest in artifIcial intelligence, philosophy, psychol ogy, software engineering and linguistics, in the analysis and possible mechanisation of human practical reasoning. Continuing the ancient quest that began with Aristotle, computer scientists, logicians, philosophers and linguists are vigorously seeking to (...) deepen our understanding of human reasoning and argumentation. Significant communities of researchers are actively engaged in developing new approaches to logic and argumentation, which are better suited to the urgent needs of today's applications. The author of this book has, over many years, made significant contributions to the detailed analysis of practical reasoning case studies, thus providing solid foundations for new and more applicable formal logical systems. We welcome Doug Walton's new book to our series. (shrink)

This paper critically examines a formal argument against deducing ‘ought’-judgments from ‘is’-judgments, an argument suggested by a literal reading of a famous passage in Hume'sTreatise of Human Nature. According to this argument, judgments of the two kinds have different logical structures (i.e., their subjects are differently related to their predicates) and this difference disallows cross-categorical deductive inferences. I draw on Fregean accounts of the ‘is’- copula and on syntactical interpretations of ‘ought’-judgments that have become standard in deontic logic to (...) argue that twentieth century work in philosophical grammar and logic casts doubt on all three of the argument's premises. (shrink)

This essay addresses the methodology of philosophy of science and illustrates how formal and empirical methods can be fruitfully combined. Special emphasis is given to the application of experimental methods to confirmation theory and to recent work on the conjunction fallacy, a key topic in the rationality debate arising from research in cognitive psychology. Several other issue can be studied in this way. In the concluding section, a brief outline is provided of three further examples.

This chapter contains sections titled: Types of Fallacy Logical Fallacies of Historians Fallacies and Historians References.

The fallacy of composition involves differing relationships of parts to wholes complicated by the problem of group ambiguity. Our discussion begins with a brief diagnosis of important features of the fallacy. We consider a common implicit assumption and the main factors that contribute to its acceptability. Our focus will be on illuminating some common strategies rather than formal material conditions for the fallacy. This is to facilitate the critical discussion of possibilities for this fallacy.

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)

At some step in proving the Liar Paradox in natural language, a sentence is derived that seems overdetermined with respect to its semantic value. This is complemented by Tarski’s Theorem that a formal language cannot consistently contain a naive truth predicate given the laws of logic used in proving the Liar paradox. I argue that proofs of the Eubulidean Liar either use a principle of truth with non-canonical names in a fallacious way or make a fallacious use of substitution (...) of identicals. Tarski never committed the first fallacy and may have himself considered it fallacious. Nevertheless, I clarify that it is fallacious. I then argue substitution of identicals needs to be restricted within the scope of the truth predicate. A logic for truth implementing this restriction is a monotonic extension of a classical first order logic, or indeed a formalizable fragment of natural language. Proofs of Tarski’s Indefinability of Truth theorem are invalid in this logic. This approach generalizes to invalidate proofs of Liar-like paradoxes, particularly the predicate form of the Knower paradox. Consequently, such a logic can be further extended in a way that avoids Montague’s theorem for such a system. Yet, the semantic status of a Liar sentence is not fully resolved. It is no longer overdetermined; it is now underdetermined. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:A Fallacy in the Intentional FallacyJames DowneyAccording to a famous argument by W. K. Wimsatt and Monroe Beardsley, the intention of the author is neither available nor desirable as a standard by which to judge the success of a work of literary art. I wish to focus on the former allegation. The author's intention is not available as a standard by which to judge a work's success, it is (...) argued, because "If the poet succeeded in doing it [the intention], then the poem itself shows what he was trying to do. And if the poet did not succeed, then the poem is not adequate evidence, and the critic must go outside the poem."1The intent of this reasoning is not entirely clear. It is intended to pose a dilemma for intentionalism, but what is the dilemma supposed to be? What difficulty is there for intentionalism if the poem itself shows what the author's intention was? Perhaps it is supposed to follow that somehow intentionalism would be purposeless. Perhaps the point is Socratic: if the intention is successful, then the reader automatically knows it was intended, so that the intention cannot be sought. Or, perhaps it is the success which cannot be sought. The idea may be that one automatically knows the extent of success precisely to the extent that one recognizes the intention. Perhaps both points are intended.On the other side of the dilemma, suppose the intention is not successful and the critic "must go outside the poem." Is this supposed to imply that whatever meaning is thereby discovered will not be the poem's meaning? Or, is the idea that being forced to go outside the poem for evidence of its meaning violates some essential goal of intentionalism? [End Page 149]It is not my main concern, however, to question the implications of the argument's premises. I wish to challenge the basic premise, itself, that if an intention is successful then the work would show that it was the author's intention. I will assume that this means, at least, that the reader would understand a certain intention and know that it was the author's intention, and that the work would provide this knowledge.Sometimes an author deliberately composes without thematic intentions. I take my example from cinematic art because it is a particularly striking example, and the point clearly holds for other forms of art. Furthermore, the intentional fallacy is usually thought to apply to other forms of art in addition to literary art. So, let us consider the method which Salvador Dalí claims that he and Luis Buñuel used when creating Un Chien Andalou, to put together whatever images came to their mind without any particular intentions directing them. Indeed, Dalí claimed, if there was even a pause between the artists, a mere moment when it seemed as though some directed thought might be beginning to take hold of them, he and Buñuel immediately discarded that idea. They retained only those ideas which arose with no thematic intentions, or intentions as to larger meaning. (We may set aside the fact that there were still formal intentions, such as what images to present, in what order, etc.—although even this can be eliminated to some degree, as when an artist cuts up bits of sound tapes and splices them together willy-nilly, and so forth.) In such a work of art, it is not possible that any such intentions be shown, since there are none.But there is still a definite intention behind such art, namely, the intention to compose with no thematic intentions. This intention could be successfully shown to an audience through a work, certainly. However, Dalís often intend otherwise (so they say). They may intend not to reveal whether or not there are certain, or even any, thematic intentions (perhaps that is an intentional anti-religious theme in that scene in Un Chien Andalou, after all; we do not know.) Perhaps, even, Dalí does not want us to know whether he wants us not to know. An intention not to reveal might apply to the intention not to reveal. What a grand game... (shrink)

Crupi et al. (2008) offer a confirmation-theoretic, Bayesian account of the conjunction fallacy—an error in reasoning that occurs when subjects judge that Pr( h 1 & h 2 | e ) > Pr( h 1 | e ). They introduce three formal conditions that are satisfied by classical conjunction fallacy cases, and they show that these same conditions imply that h 1 & h 2 is confirmed by e to a greater extent than is h 1 alone. Consequently, they (...) suggest that people are tracking this confirmation relation when they commit conjunction fallacies. I offer three experiments testing the merits of Crupi et al.’s account specifically and confirmation-theoretic accounts of the conjunction fallacy more generally. The results of Experiment 1 show that, although Crupi et al.’s conditions do seem to be causally linked to the conjunction fallacy, they are not necessary for it; there exist cases that do not meet their three conditions in which subjects still tend to commit the fallacy. The results of Experiments 2 and 3 show that Crupi et al.’s conditions, and those offered by other confirmation-theoretic accounts of the fallacy, are not sufficient for the fallacy either; there exist cases that meet all three of CFT’s conditions in which subjects do not tend to commit the fallacy. Additionally, these latter experiments show that such confirmation-theoretic conditions are at best only weakly causally relevant to the presence of the conjunction fallacy. Given these findings, CFT’s account specifically, and any general confirmation-theoretic account more broadly, falls short of offering a satisfying explanation of the presence of the conjunction fallacy. (shrink)

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

As Russell's paradox of "the set of all sets that do not contain themselves" indicated long ago, matters go seriously amiss if one operates an ontology of unrestricted totalization. Some sort of restriction must be placed on such items as "the set of all sets that have the feature F' or "the conjunction of all truths that have the feature G." But generally, logicians here introduce such formalized and complex devices as the theory of types or the doctrine of impredictivity. (...) The present paper argues for the informal and elementary idea that the items invoked in a proper identification have themselves already been identified. Even as an explanation is not satisfactory that proceeds in terms of items that themselves require prior explanation, so the same holds with identification. And heed of this elementary idea suffices to sideline those otherwise paradoxical perplexities. (shrink)

Formal epistemology is just what it sounds like: epistemology done with formal tools. Coinciding with the general rise in popularity of experimental philosophy, formal epistemologists have begun to apply experimental methods in their own work. In this entry, I survey some of the work at the intersection of formal and experimental epistemology. I show that experimental methods have unique roles to play when epistemology is done formally, and I highlight some ways in which results from (...) class='Hi'>formal epistemology have been used fruitfully to advance epistemically‐relevant experimental work. The upshot of this brief, incomplete survey is that formal and experimental methods often constitute mutually informative means to epistemological ends. (shrink)

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

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

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 (...) class='Hi'>fallacies. (shrink)

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

The traditional fallacy of many questions, also known as the fallacy of complex question, illustrated by the question, "Have you stopped sexually harassing your students?", has been known since ancient times, but is still alive and well. What is of practical importance about this fallacy is that it represents a tactic of entrapment that is very common in everyday argumentation, as well as in special kinds of argumentation like that in a legal trial or a parliamentary debate. The tactic combines (...) the use of loaded questions with the complexity of the question. A key notion is that of the presupposition of the question. How to deal with such questions is a point of departure for interrogative theory, and for any attempts to construct formal dialogues of a kind that can be used as normative models of argumentation. (shrink)

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)

Do incompatibilist arguments, like some fatalist arguments, rest on modal fallacies? If Westphal (2012) is right, then one popular argument for incompatibilism van Inwagen’s “First Formal Argument” does rest on a modal fallacy. Similarly, Warfield (2000) claims that the standard modal formulation of the master argument for incompatibilism is a modal fallacy. Here, I refute both claims. Contra Westphal, I show that the mistake in van Inwagen’s "First Formal Argument" is no modal fallacy. After that, I argue (...) that Warfield’s charge of modal fallacy can be easily avoided by using a plausible principle concerning actuality. Then, I show that this allows one to put forward a fairly simple argument for fatalism (the thesis that we aren’t able to do otherwise from what we actually do). (shrink)

This paper describes a formal measure of epistemic justification motivated by the dual goal of cognition, which is to increase true beliefs and reduce false beliefs. From this perspective the degree of epistemic justification should not be the conditional probability of the proposition given the evidence, as it is commonly thought. It should be determined instead by the combination of the conditional probability and the prior probability. This is also true of the degree of incremental confirmation, and I argue (...) that any measure of epistemic justification is also a measure of incremental confirmation. However, the degree of epistemic justification must meet an additional condition, and all known measures of incremental confirmation fail to meet it. I describe this additional condition as well as a measure that meets it. The paper then applies the measure to the conjunction fallacy and proposes an explanation of the fallacy. (shrink)

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

This project tackles the problem of analyzing a specific form of reasoning called ‘sunk costs’ in economics and ‘argument from waste’ in argumentation theory. The project is to build a normative structure representing the form of the argument, and then to apply this normative structure to actual cases in which the sunk costs argument has been used. The method is partly structural and partly empirical. The empirical part is carried out through the analysis of case studies of the sunk costs (...) argument found in business decision-making, as well as other areas like medical decision-making and everyday conversational argumentation. The structural part is carried out by using existing methods and techniques from argumentation theory, like argumentation schemes. The project has three especially significant findings. First, the sunk costs argument is not always fallacious, and in many cases it can be seen to be a rational precommitment strategy. Second, a formal model of argumentation, called practical reasoning, can be constructed that helps a rational critic to judge which sunk costs arguments are fallacious and which are not. Third, this formal model represents an alternative model of rationality to the cost-benefit model based on Bayesian calculation of probabilities. This alternative model is called the argumentation model, and it is based on interpersonal reasoning in dialogue as the model of rational thinking. This model in turn is based on the underlying notion of commitment in dialogue. (shrink)

Formal dialectic has its roots in ancient dialectic. We can trace this influence in Charles Hamblin’s book on fallacies, in which he introduced his first formal dialectical systems. Earlier, Paul Lorenzen proposed systems of dialogical logic, which were in fact formal dialectical systems avant la lettre, with roles similar to those of the Greek Questioner and Answerer. In order to make a comparison between ancient dialectic and contemporary formal dialectic, I shall formalize part of the (...) Aristotelian procedure for Academic debates. The resulting system will be compared (1) with Van Eemeren and Grootendorst’s system of rules of Critical Discussion (the pragma-dialectical discussion procedure), which must, however, first itself be reconstructed as a formal dialectical system, and (2) with a Hamblin-type system, and (3) a Lorenzen-type system. When drawing comparisons, it will become clear that there is a line to be drawn from Aristotle to formal dialectic and pragma-dialectics, extending to contemporary computational models of argument. (shrink)

I begin by formulating the problem of the nature of fallacy in terms of the logic of the negative evaluation of argument, that is, in terms of a theory of logical criticism; here I discuss several features of my approach and several advantages vis-à-vis other approaches; a main feature of my approach is the concern to avoid both formalist and empiricist excesses. I then define six types of fallaciousness, labeled formal, explanatory, presuppositional, positive, semantical, and persuasive; they all involve (...) arguments whose conclusion may be said not to follow from the premises, that is, they involve the logical evaluation of relationships among propositions. I also provide a set of data consisting of four historical cases or nine specific instances of fallacious arguments; these all pertain to the Copernican controversy about the earth's motion in the seventeenth century. I end with a discussion of further problems and inquiries that deserve attention. (shrink)

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

Aristotle studies syllogistic argumentation in Sophistical Refutations and Prior Analytics. In the latter he focuses on the formal and syntactic character of arguments and treats the sullogismoi and non-sullogismoi as argument patterns with valid or invalid instances. In the former Aristotle focuses on semantics and rhetoric to study apparent sullogismoi as object language arguments. Interpreters usually take Sophistical Refutations as considerably less mature than Prior Analytics. Our interpretation holds that the two works are more of a piece than previously (...) believed and, indeed, that Aristotle's treatment of fallacious reasoning presupposes the results of the formal theory. (shrink)

The conjunction fallacy has been a key topic in debates on the rationality of human reasoning and its limitations. Despite extensive inquiry, however, the attempt to provide a satisfactory account of the phenomenon has proved challenging. Here we elaborate the suggestion (first discussed by Sides, Osherson, Bonini, & Viale, 2002) that in standard conjunction problems the fallacious probability judgements observed experimentally are typically guided by sound assessments of _confirmation_ relations, meant in terms of contemporary Bayesian confirmation theory. Our main (...) class='Hi'>formal result is a confirmation-theoretic account of the conjunction fallacy, which is proven _robust_ (i.e., not depending on various alternative ways of measuring degrees of confirmation). The proposed analysis is shown distinct from contentions that the conjunction effect is in fact not a fallacy, and is compared with major competing explanations of the phenomenon, including earlier references to a confirmation-theoretic account. (shrink)

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

Many philosophers have considered logical reasoning as an inborn ability of mankind and as a distinctive feature in the human mind; but we all know that the distribution of this capacity, or at any rate its development, is very unequal. Few people are able to set up a cogent argument; others are at least able to follow a logical argument and even to detect logical fallacies. Nevertheless, even among educated persons there are many who do not even attain this (...) relatively modest level of development. According to my personal observations, lack of logical ability may be due to various circumstances. In the first place, I mention lack of general intelligence, insufficient power of concentration, and absence of formal education. Secondly, however, I have noticed that many people are unable, or sometimes rather unwilling, to argue ex hypothesi; such persons cannot, or will not, start from premisses which they know or believe to be false or even from premisses whose truth is not, in their opinion, sufficient ly warranted. Or, if they agree to start from such premisses, they sooner or later stray away from the argument into attempts first to settle the truth or falsehood of the premisses. Presumably this attitude results either from lack of imagination or from undue moral rectitude. On the other hand, proficiency in logical reasoning is not in itself a guarantee for a clear theoretic insight into the principles and foundations of logic. (shrink)