This essay addresses the collapse/incoherence problem for normative frameworks that contain both fundamental values and rules for promoting those values. The problem is that in some cases, we would bring about more of the fundamental value by violating the framework’s rules than by following them. In such cases, if the framework requires us to follow the rules anyway, then it appears to be incoherent; but if it allows us to make exceptions to the rules, then the framework “collapses” into one (...) that doesn’t make use of rules in the first place. The chapter begins with an examination of happiness and truth as fundamental values in Mill’s work, which lead into parallel versions of the collapse/incoherence problem in ethics and epistemology. It then sets out the collapse problem for rule-consequentialist approaches in ethics, truth-directed accounts of justification in epistemology, and epistemological approaches to argument cogency. The chapter closes with discussion of two potential solutions to the problem. (shrink)

The translation into French of the English word “fallacy” opens a discussion on the difference between fallacy and sophism in English. The two words are sometimes synonyms, but a difference is sometimes made on the ground that a sophism is deliberate and a fallacy is non-deliberate. In a second part of the paper this distinctive criterion is taken seriously to discuss the relative frequency of sophisms and of fallacies for a typical kind of fallacious argument. I claim that this aspect (...) should be taken into account by a theory of fallacious argument. (shrink)

The quality of our public discourse – think of the climate change debate for instance – is never very high. A day spent observing it reveals a litany of misrepresentation and error, argumentative fallacy, and a general lack of good will. In this paper I focus on a microcosmic aspect of these practices: the use of two types of argument – the argumentum ad hominem and appeal to authority – and a way in which they are related. Public debate is (...) so contaminated by the misuse of the ad hominem tactic that it is important to have an understanding of one of the ways in which its use may be legitimate. So readers who might have expected an analysis of the ad hominem fallacy will, on the contrary, be presented with an account of one of the places for its potential success. In ad hominem, arguers are viewed as legitimate constitutive targets for their own argument; in authority arguments, arguers provide a legitimate constitutive warrant for an argument they deploy. These types of argument are connected in so far as the identities of persons deploying them carry the cognitive weight of the argument. If authority arguments sometimes deserve to succeed, ad hominem attacks on them are potentially legitimate. An important motivation for this analysis is that in identifying the success conditions for one of the ad hominem types we attain some clarity in the evaluation of their use. (shrink)

The five English words—sentence, proposition, judgment, statement, and fact—are central to coherent discussion in logic. However, each is ambiguous in that logicians use each with multiple normal meanings. Several of their meanings are vague in the sense of admitting borderline cases. In the course of displaying and describing the phenomena discussed using these words, this paper juxtaposes, distinguishes, and analyzes several senses of these and related words, focusing on a constellation of recommended senses. One of the purposes of this paper (...) is to demonstrate that ordinary English properly used has the resources for intricate and philosophically sound investigation of rather deep issues in logic and philosophy of language. No mathematical, logical, or linguistic symbols are used. Meanings need to be identified and clarified before being expressed in symbols. We hope to establish that clarity is served by deferring the extensive use of formalized or logically perfect languages until a solid “informal” foundation has been established. Questions of “ontological status”—e.g., whether propositions or sentences, or for that matter characters, numbers, truth-values, or instants, are “real entities”, are “idealizations”, or are “theoretical constructs”—plays no role in this paper. As is suggested by the title, this paper is written to be read aloud. -/- I hope that reading this aloud in groups will unite people in the enjoyment of the humanistic spirit of analytic philosophy. (shrink)

This paper examines the views of Fogelin, Woods, Johnstone, etc., concerning deep disa-greements, force-five standoffs, philosophical controversies, etc. My approach is to reconstruct their views and critiques of them as meta-arguments, and to elaborate the meta-argumentative aspects of radical disa-greements. It turns out that deep disagreements are resolvable to a greater degree than usually thought, but only by using special principles and practices, such as meta-argumentation, ad hominem argumentation, Ramsey’s principle, etc.

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)

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

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 in two parts. Part I outlines three traditional approaches to the teaching of critical thinking: the normative, cognitive psychology, and educational approaches. Each of these approaches is discussed in relation to the influences of various methods of critical thinking instruction. The paper contrasts these approaches with what I call the “visualisation” approach. This approach is explained with reference to computer-aided argument mapping (CAAM) which uses dedicated computer software to represent inferences between premise and conclusions. The paper presents (...) a detailed account of the CAAM methodology, and theoretical justification for its use, illustrating this with the argument mapping software Rationale™. A number of Rationale™ design conventions and logical principles are outlined including the principle of abstraction, the MECE principle, and the “Holding Hands” and “Rabbit Rule” heuristics. Part II of this paper outlines the growing empirical evidence for the effectiveness of CAAM as a method of teaching critical thinking. (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.

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)

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)

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)

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.

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)

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)

(2000). ROBERT LESLIE ELLIS AND JOHN STUART MILL ON THE ONE AND THE MANY OF FREQUENTISM. British Journal for the History of Philosophy: Vol. 8, No. 2, pp. 251-274.

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)

Pierre Trémaux’s 1865 ideas on speciation have been unjustly derided following his acceptance by Marx and rejection by Engels, and almost nobody has read his ideas in a charitable light. Here we offer an interpretation based on translating the term sol as “habitat”, in order to show that Trémaux proposed a theory of allopatric speciation before Wagner and a punctuated equilibrium theory before Gould and Eldredge, and translate the relevant discussion from the French. We believe he may have influenced Darwin’s (...) revision to the third edition of the Origin on rates of evolution, and suggest that Gould’s dismissal of Trémaux is motivated by concern that others might think punctuated equilibrium theory was tainted by a connection with Trémaux. (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.

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)

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)

It is usually accepted that deductions are non-informative and monotonic, inductions are informative and nonmonotonic, abductions create hypotheses but are epistemically irrelevant, and both deductions and inductions can’t provide new insights. In this article, I attempt to provide a more cohesive view of the subject with the following hypotheses: (1) the paradigmatic examples of deductions, such as modus ponens and hypothetical syllogism, are not inferential forms, but coherence requirements for inferences; (2) since any reasoner aims to be coherent, any inference (...) must be deductive; (3) a coherent inference is an intuitive process where the premises should be taken as sufficient evidence for the conclusion, which on its turn should be viewed as necessary evidence for the premises in some modal range; (4) inductions, properly understood, are abductions, but there are no abductions beyond the fact that in any inference the conclusion should be regarded as necessary evidence for the premises; (5) monotonicity is not only compatible with the retraction of past inferences given new information, but it is a requirement for it; (6) this explanation of inferences holds true for discovery processes, predictions and trivial inferences. (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)

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)

This volume presents a selection of papers reflecting key theoretical issues in argumentation theory. Its six sections are devoted to specific themes, including the analysis and evaluation of argumentation, argument schemes and the contextual embedding of argumentation. The section on general perspectives on argumentation discusses the trends of empiricalization, contextualization and formalization, offers descriptions of the analytical and evaluative tools of informal logic, and highlights selected principles that argumentation theorists do and do not agree upon. In turn, the section on (...) linguistic approaches to argumentation focuses on the problem of distinguishing between explanation and argument, while also elaborating on the role of verbal indicators of argument schemes. All essays included in this volume point out notable recent developments in the study of argumentation. (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.

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.

This is a critical examination of Johnstone's thesis that all valid philosophical arguments are ad hominem. I clarify his notions of valid, philosophical, and ad hominem. I illustrate the thesis with his refutation ofthe claim that only ordinary language is correct. r discuss his three supporting arguments (historical, theoretical, and intermediate). And r criticize the thesis with the objections that if an ad hominem argument is valid, it is really ad rem; that it's unclear how his own theoretical argument can (...) be ad hominem; that if an ad hominem argument is really valid, it would have to be based on the proponent's own assumptions; and that the thesis is not true of philosophical arguments that are constructive rather than critical. (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)

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)

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)

Charles S. Peirce frequently mentioned reading Richard Whately's Elements of Logic when he was 12 years old. Throughout his life, Peirce emphasized the importance of that experience. This valorization of Whately is puzzling at first. Early in his career Peirce rejected Whately's central logical doctrines. What valuable insight concerning logic was robust enough to survive these specific rejections? Peirce recommended a biographical approach to understanding his philosophy. This essay follows that suggestion by considering Peirce's reading of Whately in a larger (...) life context. Surprisingly many factors in Charles Peirce's personal and intellectual development were at play when he read Whately. His father, Benjamin Peirce, oversaw rigorous home schooling intended to train young Charley for a brilliant intellectual career. Laboratory experience with qualitative chemical analysis exposed the boy to the logic of scientific investigation, specifically to the hypothetico-deductive method of inquiry. However, tensions between father and son developed over Charles' wish to devote his life to studying the logic of science. The two also disagreed upon the value of formal science. Against this background we will review relevant logical doctrines of Whately's book, as well as his innovative formalizing practice of logical inquiry. Then we will see that it was Whately's lessons about formal science that were of such importance to Peirce. (shrink)

§§3-4 of the Begriffsschrift present Frege’s objections to a dominant if murky nineteenth-century semantic picture. I sketch a minimalist variant of the pre-Fregean picture which escapes Frege’s criticisms by positing a thin notion of semantic content which then interacts with a multiplicity of kinds of truth to account for phenomena such as modality. After exploring several ways in which we can understand the existence of multiple truth properties, I discuss the roles of pointwise and setwise truth properties in modal logic. (...) I argue that thinking of supertruth and determinate truth as setwise truth properties allows an understanding of supervaluationist approaches to vagueness which escapes both Williamson’s objections to and a needless metalinguistic orientation of traditional supervaluationism. (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 entry traces the historical development of the Square of Opposition, a collection of logical relationships traditionally embodied in a square diagram. This body of doctrine provided a foundation for work in logic for over two millenia. For most of this history, logicians assumed that negative particular propositions ("Some S is not P") are vacuously true if their subjects are empty. This validates the logical laws embodied in the diagram, and preserves the doctrine against modern criticisms. Certain additional principles ("contraposition" (...) and "obversion") were sometimes adopted along with the Square, and they genuinely yielded inconsistency. By the nineteenth century an inconsistent set of doctrines was widely adopted. Strawson's 1952 attempt to rehabilitate the Square does not apply to the traditional doctrine; it does salvage the nineteenth century version but at the cost of yielding inferences that lead from truth to falsity when strung together. (shrink)

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

The fallacy of ignoring qualifications, or secundum quid et simpliciter, is a deceptive strategy that is pervasive in argumentative dialogues, discourses, and discussions. It consists in misrepresenting an utterance so that its meaning is broadened, narrowed, or simply modified to pursue different goals, such as drawing a specific conclusion, attacking the interlocutor, or generating humorous reactions. The “secundum quid” was described by Aristotle as an interpretative manipulative strategy, based on the contrast between the “proper” sense of a statement and its (...) meaning taken absolutely or in a certain respect. However, how can an “unqualified” statement have a proper meaning different from the qualified one, and vice versa? This “linguistic” fallacy brings to light a complex relationship between pragmatics, argumentation, and interpretation. The secundum quid is described in this paper as a manipulative argument, whose deceptive effect lies in its pragmatic dimension. This fallacy is analyzed as a strategy of decontextualization lying at the interface between pragmatics and argumentation and consisting of the unwarranted passage from an ut-terance to its semantic representation. By ignoring the available evidence and the presumptive interpretation of a statement, the speaker places it in a different context or suppresses textual and contextual evidence to infer a specific meaning different from the presumable one. (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)