Jesus has been accused of committing a fallacy (of denying the antecedent) at John 8:47. Careful analysis of this text (1) reveals a hitherto unrecognized valid form of argument which can superficially look like the predicate-logic analogue of denying the antecedent; (2) shows that determining whether a published text can be fairly charged with committing a fallacy may require (but often does not get) extensive and detailed analysis; (3) acquits Jesus of the charge; and thereby (4) conflnns a claim by (...) Michael Burke that published arguments can seldom be fairly charged with denying the antecedent, or analogous fallacies. (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)

This paper discusses the fallacies of combination and division as they are presented by Aristotle in chapter 4 of his Sophistici Elenchi. Aristotle's examples are concise, their discussion is unclear, and it is difficult to distinguish the cases of combination from those of division. I analyse the Aristotelian examples and the interpretations offered so far. I show that these interpretations suffer from a major defect: they fail to identify a common characteristic whereby the Aristotelian examples can be classified as instances (...) of combination or division. In my reconstruction of the examples, I repair this deficiency: I give a single pattern of explanation for the fallacy of combination and another (similar) pattern for the fallacy of division. Thus, it is possible to free Aristotle from the following charges: (i) he did not clearly distinguish between combination and division, and (ii) he reduced combination and division to a single fallacy. My explanation of the fallacies uses the notion of scope of an expression: in modern terminology, the fallacy of combination can be described as ?fallacy of the wide scope?, the fallacy of division as ?fallacy of the narrow scope? (shrink)

This paper offers an account of a fallacy we will call bothsiderism, which is to mistake disagreement on an issue for evidence that either a compromise on, suspension of judgment regarding, or continued discussion of the issue is in order. Our view is that this is a fallacy of a unique and heretofore untheorized type, a fallacy of meta-argumentation. The paper develops as follows. After a brief introduction, we examine a recent bothsiderist case in American politics. We use this as (...) a pivot point to survey the theoretical literature on the fallacy. The most prominent theory is that bothsiderism is a case of dialogue-shifting. This view fails, we maintain, to explain how bothsiderism might be persuasive. We argue, rather, bothsiderism is a kind of meta-argumentative fallacy. (shrink)

Hypotheticals, conditionals, and their connecting relation, implication, dramatically changed their meanings during the nineteenth and early part of the twentieth century. Modern logicians ordinarily do not distinguish between the terms hypothetical and conditional. Yet in the late nineteenth century their meanings were quite different, their ties to the implication relation either were unclear, or the implication relation was used exclusively as a logical operator. I will trace the development of implication as an inference operator from these earlier notions into the (...) first third of the twentieth century using as the starting point the ideas primarily of R. Whately and W. Hamilton before discussing the work of the transitional logicians, A. De Morgan and G. Boole on these topics. Then we discuss the relevant views of four prominent but relatively unknown nineteenth century British logicians, W.E. Johnson, J.N. Keynes, E.E.C. Jones, and H. MacColl, as well as those of the more influential logicians, W.S. Jevons and J. Venn, closing with a section on ‘implication as inference’ where we explore some key ideas of B. Russell and sketch the work of D. Hilbert, P. Hertz, and G. Gentzen who together are responsible for the development of the modern ideas related to the subjects of this paper. (shrink)

Most recent discussions of John Stuart Mill’s System of Logic (1843) neglect the fifth book concerned with logical fallacies. Mill not only follows the revival of interest in the traditional Aristotelian doctrine of fallacies in Richard Whately and Augustus De Morgan, but he also develops new categories and an original analysis which enhance the study of fallacies within the context of what he calls ‘the philosophy of error’. After an exploration of this approach, the essay relates the philosophy of error (...) to the discussion of truth and error in chapter two of On Liberty (1859) concerned with freedom of thought and discussion. Drawing on Socratic and Baconian perspectives, Mill defends both the traditional study of logic against Jevons, Boole, De Morgan, and others, as well as the study of fallacies as the key to maintaining truth and its dissemination in numerous fields, such as science, morality, politics, and religion. In Mill’s view the study of fallacies also liberates ordinary people to explore the truth and falsity of ideas and, as such, to participate in society and politics and develop themselves as progressive beings. (shrink)

The preface paradox strikes us as puzzling because we feel that if a person holds a set of inconsistent beliefs, i.e. beliefs such that at least one of them must be correct, then he should give at least one of them up. Equally, if a person's belief is rational, then he has a right to hold it. Yet the preface example is prima facie a case in which a person holds an inconsistent set of beliefs each of which is rational, (...) and thus a case in which that person has a duty to relinquish what he has a right to keep. (shrink)

This essay examines Augustus DeMorgan's chapter on fallacy in his Formal Logic (1847) in order to show how DeMorgan's treatment represents an expansion and advance upon Aristotle. It is important that Aristotle clearly distinguishes among dialectical, didactic, demonstrative, and contentious types of argument, based upon the acceptability of premises and the aims of participants. Appropriating Aristotle's list of fallacies, DeMorgan discusses examples that reveal how the charge and countercharge of fallacy function in contentious argument, which is more widespread than Aristotle (...) imagined. DeMorgan's treatment of fallacy is in the spirit of Aristotle because of its focus on dialogue arguments, but it represents an advance because it expands the possible scenes of contention and shows how unshared premises and the will to win inform many argument situations. The emphasis on contention in natural-language argument puts DeMorgan in the company of his l9th century peers, Mill and Whately. (shrink)

SummaryThis paper studies some classic cases of the fallacy of begging the question based on appeals to testimony containing circular reasoning. For example, suppose agents a, b and c vouch for d’s credentials, and agents b, d, and e vouch for a’s credentials. Such a sequence of reasoning is circular because a is offering testimony for d but d is offering testimony for a. The paper formulates and evaluates restrictions on the use of testimonial evidence that might be used to (...) deal with such problematic arguments. One is called the Non-repeater Rule: in an extended sequence of argumentation based on testimony, once a source x has been appealed to at any given point in the sequence, that same source x must never be appealed to again at any next point in the same sequence. (shrink)

This article outlines criteria for the evaluation of the argumentum ad hominem (argument against the person, or personal attack in argument) that is traditionally a part of the curriculum in informal logic. The argument is shown to be a kind of criticism which works by shifting the burden of proof in dialogue through citing a pragmatic inconsistency in an arguer's position. Several specific cases of ad hominem argumentation which pose interesting problems in analyzing this type of criticism are studied.

This paper addresses the problem posed by the current split between the two opposed hypotheses in the growing literature on the fallacy of begging the question the epistemic hypothesis, based on knowledge and belief, and the dialectical one, based on formal dialogue systems. In the first section, the nature of split is explained, and it is shown how each hypothesis has developed. To get the beginning reader up to speed in the literature, a number of key problematic examples are analyzed (...) illustrating how both approaches can be applied. Useful tools are brought to bear on them, including the automated argument diagramming system Araucaria, and profiles of dialogue used to represent circular argumentation in a dialogue tableau format. These tools are used to both to model circular reasoning and to provide the contextual evidence needed to properly determine whether the circular reasoning in a given case is better judged fallacious or not. A number of technical problems that have impeded the development of both hypotheses are studied. One central problem is the distinction between argument and explanation. It is concluded that the best way to move forward and solve these problems is to reformulate the two hypotheses in such a way that they might be able to co-exist. On this basis, a unified methodology is proposed that allows each hypothesis to move forward as a legitimate avenue for research using the same tools. (shrink)

The aim of this paper is to make it clear how and why begging the question should be seen as a pragmatic fallacy which can only be properly evaluated in a context of dialogue. Included in the paper is a review of the contemporary literature on begging the question that shows the gradual emergence over the past twenty years or so of the dialectical conception of this fallacy. A second aim of the paper is to investigate a number of general (...) problems raised by the pragmatic framework. (shrink)

Imperatives cannot be true or false, so they are shunned by logicians. And yet imperatives can be combined by logical connectives: "kiss me and hug me" is the conjunction of "kiss me" with "hug me". This example may suggest that declarative and imperative logic are isomorphic: just as the conjunction of two declaratives is true exactly if both conjuncts are true, the conjunction of two imperatives is satisfied exactly if both conjuncts are satisfied—what more is there to say? Much more, (...) I argue. "If you love me, kiss me", a conditional imperative, mixes a declarative antecedent ("you love me") with an imperative consequent ("kiss me"); it is satisfied if you love and kiss me, violated if you love but don't kiss me, and avoided if you don't love me. So we need a logic of three -valued imperatives which mixes declaratives with imperatives. I develop such a logic. (shrink)

Jarmo Pulkkinen, The threat of logical mathematism. A study on the critique of mathematical logic in Germany at the turn of the 20th century. Frankfurt a.M:Peter Lang, 1994. Scandinavian University Studies in the Humanities and Social Sciences; 7). 186 pp. 24 DM. ISBN 3-631-47409-1.

History witnesses alternative approaches to “the proposition”. The proposition has been referred to as the object of belief, disbelief, and doubt: generally as the object of propositional attitudes, that which can be said to be believed, disbelieved, understood, etc. It has also been taken to be the object of grasping, judging, assuming, affirming, denying, and inquiring: generally as the object of propositional actions, that which can be said to be grasped, judged true or false, assumed for reasoning purposes, etc. The (...) proposition has also been taken to be the subject of truth and falsity: generally as the subject of propositional properties, that which can be said to be true, false, tautological, informative, inconsistent,etc. It has also been taken as the subject and object of logical relations, e.g. that which can be said to imply, be implied, contradict, be contradicted, etc. Prima facie, such properties and relations are non-mental and objective. It has also been taken to be the resultants or products of propositional operations, usually mental or linguistic; e.g. judging, affirming, and denying have been held to produce propositions called judgments, affirmations, and negations, respectively. Propositions have also been taken to be certain declarative sentences. Finally,propositions have been taken to be meanings of certain declarative sentences. This essay is an informal, selective, and incomplete survey of alternative approaches to “the proposition” with special attention to the views of the late American philosopher Peter Hare (1935–2008)and of those who influenced him. DOI: 10.5007/1808-1711.2011v15n1p51. (shrink)

This paper is concerned with De Morgan’s explanation of the validity of arguments that involve relational notions. It discusses De Morgan’s expansion of traditional logic aimed at accommodating those inferences, and makes the point that his endeavour is not successful in that the rules that made up his new logic are not sound. Nevertheless, the most important scholarly work on De Morgan’s logic, and contrary to that De Morgan’s mistake is not beyond repair. The rules that determine his new logic (...) are in fact monotonie replacement rules. And provided they are restricted in the correct way, these rules are demonstrably sound. (shrink)

Why are personal attacks so powerful? In political debates, speeches, discussions and campaigns, negative character judgments, aggressive charges and charged epithets are used for different purposes. They can block the dialogue, trigger value judgments and influence decisions; they can force the interlocutor to withdraw a viewpoint or undermine his arguments. Personal attacks are not only multifaceted dialogical moves, but also complex argumentative strategies. They can be considered as premises for further arguments based on signs, generalizations or consequences. They involve tactics (...) for arousing emotions such as fear, hate or contempt, or for ridiculing the interlocutor. The twofold level of investigation presented in this paper is aimed at distinguishing the different roles that ad hominem have in a dialogue and bringing to light their hidden dimensions. The reasoning structure of each type of attack will be distinguished from the tactics used to increase its effectiveness and conceal its weaknesses. (shrink)

We seek means of distinguishing logical knowledge from other kinds of knowledge, especially mathematics. The attempt is restricted to classical two-valued logic and assumes that the basic notion in logic is the proposition. First, we explain the distinction between the parts and the moments of a whole, and theories of ?sortal terms?, two theories that will feature prominently. Second, we propose that logic comprises four ?momental sectors?: the propositional and the functional calculi, the calculus of asserted propositions, and rules for (...) (in)valid deduction, inference or substitution. Third, we elaborate on two neglected features of logic: the various modes of negating some part(s) of a proposition R, not only its ?external? negation not-R; and the assertion of R in the pair of propositions ?it is (un)true that R? belonging to the neglected logic of asserted propositions, which is usually left unstated. We also address the overlooked task of testing the asserted truth-value of R. Fourth, we locate logic among other foundational studies: set theory and other theories of collections, metamathematics, axiomatisation, definitions, model theory, and abstract and operator algebras. Fifth, we test this characterisation in two important contexts: the formulation of some logical paradoxes, especially the propositional ones; and indirect proof-methods, especially that by contradiction. The outcomes differ for asserted propositions from those for unasserted ones. Finally, we reflect upon self-referring self-reference, and on the relationships between logical and mathematical knowledge. A subject index is appended. (shrink)

The introduction has a brief statement, sufficient for the purpose of this paper, which describes in general terms the notion of probability logic on which the paper is based. Contributions made in the eighteenth century by Leibniz, Jacob Bernoulli and Lambert, and in the nineteenth century by Bolzano, De Morgan, Boole, Peirce and MacColl are critically examined from a contemporary point of view. Historicity is maintained by liberal quotations from the original sources accompanied by interpretive explanation. Concluding the paper is (...) a summary. (shrink)

Peter Geach describes the 'doctrine of distribution' as the view that a term is distributed if it refers to everything that it denotes, and undistributed if it refers to only some of the things that it denotes. He argues that the notion, so explained, is incoherent. He claims that the doctrine of distribution originates from a degenerate use of the notion of ?distributive supposition? in medieval supposition theory sometime in the 16th century. This paper proposes instead that the doctrine of (...) distribution occurs at least as early as the 12th century, and that it originates from a study of Aristotle's notion of a term's being ?taken universally?, and not from the much later theory of distributive supposition. A detailed version of the doctrine found in the Port Royal Logic is articulated, and compared with a slightly different modern version. Finally, Geach's arguments for the incoherence of the doctrine are discussed and rejected. (shrink)

The two different layers of logical theory—epistemological and ontological—are considered and explained. Special attention is given to epistemic assumptions of the kind that a judgement is granted as known, and their role in validating rules of inference, namely to aid the inferential preservation of epistemic matters from premise judgements to conclusion judgement, while ordinary Natural Deduction assumptions serve to establish the holding of consequence from antecedent propositions to succedent proposition.

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)

Argument from analogy is a common and formidable form of reasoning in law and in everyday conversation. Although there is substantial literature on the subject, according to a recent survey ( Juthe 2005) there is little fundamental agreement on what form the argument should take, or on how it should be evaluated. Th e lack of conformity, no doubt, stems from the complexity and multiplicity of forms taken by arguments that fall under the umbrella of analogical reasoning in argumentation, dialectical (...) studies, and law. Modeling arguments with argumentation schemes has proven useful in attempts to refine the analyst’s understanding of not only the logical structures that shape the backbone of the argument itself, but also the logical underpinning of strategies for evaluating it, strategies based on the semantic categories of genus and relevance. By clarifying the distinction between argument from example and argument from analogy, it is possible to advance a useful proposal for the treatment of argument from analogy in law. (shrink)

Inductive generalization asserts that what obtains in known instances can be generalized to all. Its original form is enumerative induction, the earliest form of inductive inference, and it has been elaborated in various ways, largely with the goal of extending its reach. Its principal problem is that it supplies no intrinsic notion of strength of support so that one cannot tell if the generalization has weak or strong support.

Following a brief preface, the second section of this paper discusses Mill's early reflections on the problem of how deductive inference can be illuminating. In the third section it is suggested that in his Logic Mill misconstrued the feature that the premises of a logically valid argument contain the conclusion as the ground of a charge that deductive proof is question-begging. The fourth section discusses the nature of the traditional petitio objection to syllogism, and the fifth shows that Mill had (...) a theory capable of answering it. The final section cites the confusion described in section 3 to explain why Mill nevertheless continued to think that syllogistic proofs beg the question. (shrink)

The aim of this paper is to propose foundations for a formal model of representation and numerical evaluation of a possibly broad class of arguments, including those that occur in natural discourse. Since one of the most characteristic features of everyday argumentation is the occurrence of convergent reasoning, special attention should be paid to the operation ⊕, which allows us to calculate the logical force of convergent arguments with an accuracy not offered by other approaches.

Peter H. Hare (1935-2008) developed informed, original views about the proposition: some published (Hare 1969 and Hare-Madden 1975); some expressed in conversations at scores of meetings of the Buffalo Logic Colloquium and at dinners following. The published views were expository and critical responses to publications by Curt J. Ducasse (1881-1969), a well-known presence in American logic, a founder of the Association for Symbolic Logic and its President for one term.1Hare was already prominent in the University of Buffalo's Philosophy Department in (...) 1969 when I was appointed. Soon after, he became Chair. As his Associate Chair from 1971to 1975, I spent many hours with him in Buffalo and on professional trips .. (shrink)

In this essay, my aim is twofold: to clarify how the late Mill conceived of the certainty of inductive generalizations and to offer a systematic clarification of the limited domain of application of the Mill’s Canons of Induction. I shall argue that Mill’s views on the certainty of knowledge changed overtime and that this change was accompanied by a new view on the certainty of the inductive results yielded by the Canons of Induction. The key message of the later editions (...) of The System of Logic as conceived by the late Mill was no longer that by the Canons of Induction we can establish scientific certainty and true causes, but rather that the Canons are useful in establishing causal laws in a provisional way. (shrink)

This paper deals with the treatment of figures of speech in Perelman’s and Olbrechts-Tyteca’s Treatise on Argumentation (TA), and, more broadly, with the place of figures in argumentation theory. The contrast between two conceptions (or two domains)\n of rhetoric, “a rhetoric of figures” and “a rhetoric of argument” can be traced back to Ramus, and it has been revived in\n the seventies through the perception of an incommensurability between Perelman’s “New Rhetoric” and the École de Liège’s “General\n Rhetoric”. Modern theories (...) of argumentation, oriented towards the characterization and denunciation of fallacious discourse,\n emphasize the gap between sound argumentative discourse and rhetorical discourse seen as a “powerful instrument of error and\n deceit” (Locke). This concept of argument presupposes a vision of language as ideal/transparent—a revised language that is\n not the language of ordinary argumentation. Figures are not basically “decorative”; they are manifestations of the complex\n process of language structuring in speech. Thus rejecting figures amounts to a negation of discourse as such. The second section\n turns to a somewhat neglected aspect of the TA, its both decisive and somewhat cavalier theory of figures of speech, and its extended use and re-definition of a complex set of figures. We argue that the TA, in its quest for descriptive adequacy, breaks with the traditional and comfortable concept of figures as useless fallacious\n “ornaments” and provides us with the first description of what could be characterized as the semantic level of ordinary argumentative\n discourse. This will be shown on the case of “figures of choice, presence and communion”, and could be extended to the discursive\n construction of objects and participants, including the speaker and her emotions. (shrink)

This paper discusses George Boole’s two distinct approaches to the explanatory relationship between logical and psychological theory. It is argued that, whereas in his first book he attributes a substantive role to psychology in the foundation of logical theory, in his second work he abandons that position in favour of a linguistically conceived foundation. The early Boole espoused a type of psychologism and later came to adopt a type of anti-psychologism. To appreciate this invites a far-reaching reassessment of his philosophy (...) of logic. (shrink)

(2001). Locke‐Stewart‐Mill: Philosophy of science at Dartmouth College, 1771‐1854. International Studies in the Philosophy of Science: Vol. 15, No. 2, pp. 167-175.

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

This essay explores Johnstone's idea that "rhetoric is a wedge." In particular, it explores the place of this idea in Johnstone's philosophy of argument, the need to confront this idea with argument, and ways of confronting it with ad rem and ad hominem arguments.

The phrase _secundum quid et simpliciter_ is the Latin expression translating and labelling the sophism described by Aristotle as connected with the use of some particular expression “absolutely or in a certain respect and not in its proper sense.” This paper presents an overview of the analysis of this fallacy in the history of dialectics, reconstructing the different explanations provided in the Aristotelian texts, the Latin and medieval dialectical tradition, and the modern logical approaches. The _secundum quid_ emerges as a (...) strategy that is based on the pragmatic dimension of arguments, and in particular the complex passage from an utterance (what is said) to its logical form (a proposition in an argument). The medieval and modern logical theories attempted to explain from different philosophical perspectives how the pragmatically enriched semantic representation can be achieved, justified, and most importantly manipulated. The different analyses of this fallacy bring to light various dimensions of the pragmatics of arguments, and the complex interdependence between context, meaning, and inferences. (shrink)

Presuppositions are at the same time a crucial and almost neglected dimension of arguments and fallacies. Arguments involve different types of presuppositions, which can be used for manipulative purposes in distinct ways. However, what are presuppositions? What is their dialectical function? Why and how can they be dangerous? This paper intends to address these questions by developing the pragmatic approaches to presupposition from a dialectical perspective. The use of presuppositions will be analyzed in terms of presumptive conclusions concerning the interlocutor’s (...) acceptance of a proposition, which can be assessed as reasonable or unacceptable. Their dialectical function is described in terms of dark side commitments attributed to a collective "voice" representing what is commonly shared. For this reason, they count as attempts to include the presupposed contents into the hearer’s commitment store, which in some circumstances can reverse the burden of proof. The different manipulative strategies grounded on controversial presuppositions will be examined by showing the distinct roles that the latter play and the relationship between the degrees of presuppositional implicitness and the speaker’s burden of retraction. (shrink)

Logical guarantees of validity must be understood as subject to the proviso that no equivocation is committed. But we do not have a formal theory of equivocation. This paper attempts to formulate rules for responding to equivocal arguments in the context of dialogue. What occurs when one distinguishes meanings of an equivocal expression turns out to be rather different from definition.

The situationally disqualifying ad hominem attack is an argumentative move in critical dialogue whereby one participant points out certain features in his adversary's personal situation that are claimed to make it inappropriate for this adversary to take a particular point of view, to argue in a particular way, or to launch certain criticisms. In this paper, we discuss some examples of this way of arguing. Other types of ad hominem argumentation are discussed as well and compared with the situationally disqualifying (...) type. The socalled Houtlosser Dilemma highlights the danger of unconditionally condoning ad hominem arguments. We propose a classification of ad hominem, and a more restrictive use of the term 'circumstantial'. Finally, we discuss whether ad hominem arguments are (always?) to be rejected as fallacious. (shrink)

One way to determine the quality and pace of change in a science as it undergoes a major transition is to follow some feature of it which remains relatively stable throughout the process. Following the chosen item as it goes through reinterpretation permits conclusions to be drawn about the nature and scope of the broader change in question. In what follows, this device is applied to the change which took place in logic in the mid-nineteenth century. The feature chosen as (...) the focal point is the categorical syllogism. (shrink)

Relevance is a triadic relation between an item, an outcome or goal, and a situation. Causal relevance consists in an item's ability to help produce an outcome in a situation. Epistemic relevance, a distinct concept, consists in the ability of a piece of information (or a speech act communicating or requesting a piece of information) to help achieve an epistemic goal in a situation. It has this ability when it can be ineliminably combined with other at least potentially accurate information (...) to achieve the goal. The relevance of a conversational contribution, premiss relevance and conclusion relevance are species of epistemic relevance thus defined. The conception of premiss relevance which results provides a basis for determining when the various ‘arguments ad’ called fallacies of relevance are indeed irrelevant. In particular, an ad verecundiam appeal is irrelevant if the authority cited lacks expertise in a cognitive domain to which the conclusion belongs, the authority does not exercise its expertise in coming to endorse the conclusion, or the conclusion does not belong to a cognitive domain; otherwise the ad verecundiam is relevant. (shrink)

In this paper I propose to continue the analysis of the appeal to authority begun at the last OSSA conference. I proceed by examining the well-documented use of the appeal made by the ancient Roman advocate, Cicero. The fact that Cicero expressed his opinion was expectably sufficient to give his auditors--responsible citizens all--reason to do as he desired. But why? The resolution of this puzzle points to a strong sense in which arguments can be called rhetorical , for the rational (...) force of Cicero's authority depends necessarily on what he says. (shrink)

Three distinctly different interpretations of Aristotle’s notion of a sullogismos in Prior Analytics can be traced: (1) a valid or invalid premise-conclusion argument (2) a single, logically true conditional proposition and (3) a cogent argumentation or deduction. Remarkably the three interpretations hold similar notions about the logical relationships among the sullogismoi. This is most apparent in their conflating three processes that Aristotle especially distinguishes: completion (A4-6)reduction(A7) and analysis (A45). Interpretive problems result from not sufficiently recognizing Aristotle’s remarkable degree of metalogical (...) sophistication to distinguish logical syntax from semantics and, thus, also from not grasping him to refine the deduction system of his underlying logic. While it is obvious that Aristotle most often uses ‘sullogimos’ to denote a valid argument of a certain kind, we show that at Prior Analytics A4-6, 7, 45 Aristotle specifically treats a sullogismos as an elemental argument pattern having only valid instances and that such a pattern then serves as a rule of deduction in his syllogistic logic. By extracting Aristotle’s understanding of three proof-theoretic processes, this paper provides new insight into what Aristotle thinks reasoning syllogistically is and, moreover, it resolves three problems in the most recent interpretation that takes a sullogismos to be a deduction. (shrink)