English translation of an entry on pages 137–42 of the Spanish-language dictionary of logic: Luis Vega, Ed. Compendio de Lógica, Argumentación, y Retórica. Madrid: Trotta. -/- DEDICATION: To my friend and collaborator Kevin Tracy. -/- This short essay—containing careful definitions of ‘counterargument’ and ‘counterexample’—is not an easy read but it is one you’ll be glad you struggled through. It contains some carefully chosen examples suitable for classroom discussion. -/- Using the word ‘counterexample’ instead of ‘counterargument’ in connection with Aristotle’s invalidity (...) proofs leads to a misinterpretation of Aristotle’s intentions. The two relations expressed by these two words are drastically different—as explained in this essay. There is however a subtle overlap: Every argument that is a counterargument for a given argument is a counterexample to the universal proposition that every argument in the same form as the given argument is valid. The word ‘counterexample’ was coined in the 1800s. The word ‘counterargument’ was given this sense in the 1960s. Saying that one argument is a counterexample for another argument is bad English—taking the word ‘counterexample’ in its Standard English sense. The word ‘counterinstance’ is an exact synonym for ‘counterexample’. Which logic books define ‘counterinstance’ or ‘counterexample’? Who started using ‘counterinstance’ or ‘counterexample’ in the sense of ‘counterargument’? Did they note that they were not using the word in the Standard sense? Why did it catch on? -/- Also see: https://www.academia.edu/8840909/Argumentations_and_logic_1989_ . (shrink)

Girolamo Saccheri (1667--1733) was an Italian Jesuit priest, scholastic philosopher, and mathematician. He earned a permanent place in the history of mathematics by discovering and rigorously deducing an elaborate chain of consequences of an axiom-set for what is now known as hyperbolic (or Lobachevskian) plane geometry. Reviewer's remarks: (1) On two pages of this book Saccheri refers to his previous and equally original book Logica demonstrativa (Turin, 1697) to which 14 of the 16 pages of the editor's "Introduction" are devoted. (...) At the time of the first edition, 1920, the editor was apparently not acquainted with the secondary literature on Logica demonstrativa which continued to grow in the period preceding the second edition \ref[see D. J. Struik, in Dictionary of scientific biography, Vol. 12, 55--57, Scribner's, New York, 1975]. Of special interest in this connection is a series of three articles by A. F. Emch [Scripta Math. 3 (1935), 51--60; Zbl 10, 386; ibid. 3 (1935), 143--152; Zbl 11, 193; ibid. 3 (1935), 221--333; Zbl 12, 98]. (2) It seems curious that modern writers believe that demonstration of the "nondeducibility" of the parallel postulate vindicates Euclid whereas at first Saccheri seems to have thought that demonstration of its "deducibility" is what would vindicate Euclid. Saccheri is perfectly clear in his commitment to the ancient (and now discredited) view that it is wrong to take as an "axiom" a proposition which is not a "primal verity", which is not "known through itself". So it would seem that Saccheri should think that he was convicting Euclid of error by deducing the parallel postulate. The resolution of this confusion is that Saccheri thought that he had proved, not merely that the parallel postulate was true, but that it was a "primal verity" and, thus, that Euclid was correct in taking it as an "axiom". As implausible as this claim about Saccheri may seem, the passage on p. 237, lines 3--15, seems to admit of no other interpretation. Indeed, Emch takes it this way. (3) As has been noted by many others, Saccheri was fascinated, if not obsessed, by what may be called "reflexive indirect deductions", indirect deductions which show that a conclusion follows from given premises by a chain of reasoning beginning with the given premises augmented by the denial of the desired conclusion and ending with the conclusion itself. It is obvious, of course, that this is simply a species of ordinary indirect deduction; a conclusion follows from given premises if a contradiction is deducible from those given premises augmented by the denial of the conclusion---and it is immaterial whether the contradiction involves one of the premises, the denial of the conclusion, or even, as often happens, intermediate propositions distinct from the given premises and the denial of the conclusion. Saccheri seemed to think that a proposition proved in this way was deduced from its own denial and, thus, that its denial was self-contradictory (p. 207). Inference from this mistake to the idea that propositions proved in this way are "primal verities" would involve yet another confusion. The reviewer gratefully acknowledges extensive communication with his former doctoral students J. Gasser and M. Scanlan. ADDED 14 March 14, 2015: (1) Wikipedia reports that many of Saccheri's ideas have a precedent in the 11th Century Persian polymath Omar Khayyám's Discussion of Difficulties in Euclid, a fact ignored in most Western sources until recently. It is unclear whether Saccheri had access to this work in translation, or developed his ideas independently. (2) This book is another exemplification of the huge difference between indirect deduction and indirect reduction. Indirect deduction requires making an assumption that is inconsistent with the premises previously adopted. This means that the reasoner must perform a certain mental act of assuming a certain proposition. It case the premises are all known truths, indirect deduction—which would then be indirect proof—requires the reasoner to assume a falsehood. This fact has been noted by several prominent mathematicians including Hardy, Hilbert, and Tarski. Indirect reduction requires no new assumption. Indirect reduction is simply a transformation of an argument in one form into another argument in a different form. In an indirect reduction one proposition in the old premise set is replaced by the contradictory opposite of the old conclusion and the new conclusion becomes the contradictory opposite of the replaced premise. Roughly and schematically, P,Q/R becomes P,~R/~Q or ~R, Q/~P. Saccheri’s work involved indirect deduction not indirect reduction. (3) The distinction between indirect deduction and indirect reduction has largely slipped through the cracks, the cracks between medieval-oriented logic and modern-oriented logic. The medievalists have a heavy investment in reduction and, though they have heard of deduction, they think that deduction is a form of reduction, or vice versa, or in some cases they think that the word ‘deduction’ is the modern way of referring to reduction. The modernists have no interest in reduction, i.e. in the process of transforming one argument into another having exactly the same number of premises. Modern logicians, like Aristotle, are concerned with deducing a single proposition from a set of propositions. Some focus on deducing a single proposition from the null set—something difficult to relate to reduction. (shrink)

A universal proposition is shown false by a known counterexample. A premise-conclusion argument is shown invalid by a known counterargument. The failure to distinguish counterexample from counterargument is like the failure to distinguish falsehood from invalidity.

In lieu of an abstract, here is a brief excerpt of the content:Hume and the Lockean Background: Induction and the Uniformity Principle David Owen Introduction What has come to be called Hume's problem of induction is special in many ways. It is arguably his most important and influential argument, especially when seen in its overall context of the more general argument about causaUty. It has come to be one of the great "standard problems" ofphilosophyandyetis,by most accounts, almost unique (...) in having no ancient precursor. Interestingly, the argument is frequently presented in terms that the author never used. Itis difficult for us not to think of the problem in terms of the contrast between deductive vs. inductive reasoning (or logic, or whatever). But this is a contrast nowhere to be found in Hume: he talks of demonstrative vs. probable (or moral) reasoning. Hume uses the word "induction" only twice in the Treatise1 and in neither case is it clear that the word is used toreportapieceofprobablereasoning.2One ofthefewoccurrences of"deduce" or "deducing" occurs in the second Enquiry, where he talks about "following the experimental method, and deducing general maximsfrom acomparisonofparticularinstances,"3hardlyaparadigm of what we would call deductive reasoning.4 Many modern studies of Hume that make a real attempt to understand what Hume meant by demonstration and probability, in the context of his argument about induction, tend towards the ahistorical,6 treating Hume's writings as contemporary texts. But failure to take into account some of the background concerning the nature of demonstrative and probable reason makes it unlikely, I think, that we can understand Hume's argument. Part ofthe problem is the failure to identify Hume's targets in that famous negative argument about induction (vague reference is sometimes made to the "rationalists") and part of the problem is identifying the role the uniformity principle plays in Hume's famous argumentand thelightitsheds on the conception ofprobablereasoning Hume was attacking. In this paper I want to argue that a careful look at Locke solves some ofthese problems: he has a well developed view ofdemonstrative and probable reasoning, his confidence in conformity as a ground of probability is a Ukely target of Hume's attack and his Volume XVIII Number 2 179 DAVID OWEN accountshedsmuchlightonwhatrole the principleofuniformitymight play in Hume's account.6 Of course, at a certain level of philosophical abstraction it is irrelevant whether we have understood what Hume "really meant." Theproblemofinductionhas emergedas a central onein epistemology, philosophical logic, and philosophy of science. It would be an interesting question in philosophical historiography to trace the development ofthe "problem" from Hume's time to our own but that is not my task here. I trust one needs no justification for taking an historical look at a famous problem rather than tackling the problem head-on in one's own terms. But if one is needed, here is mine: sometimes, by looking at a problem from a different, historical perspective, one sees a different problem or afamiliar problem in a new light. One's philosophical horizons are broadened. Furthermore, one may make an interesting historical discovery, or at least draw some interesting historical connections. I take it as uncontroversial that Locke, following Descartes, rejected a formal, logical account of demonstrative reasoning. Instead ofusing a formal, syllogistic account ofhow two propositions can entail a third, Locke concentrated on the relation two ideas bear one to another.7 Thus a demonstration, for Locke, getsits force, notfrom what we would call a deductive relation between one set of propositions (.the premises) and anotherproposition (the conclusion), butrather from the relation one idea bears to another, either directly, or via a chain of intermediate ideas. It is true that Locke frequently talks of inferring one proposition from another, but this is always cashed out in terms of relations ofideas via a chain ofintermediate ideas.8 It is also true that Locke occasionally uses the terms "deduce" and "deduction." But these are never used in our sense that has to do with formal deductive validity. Rather, they are simply used loosely in the informal sense of "argue" or "infer," and "argument" or "inference."9 In the rest of this paper, all uses ofthe word"deduction" andits cognates shouldbe taken as having the modern sense, unless flagged as having "Locke... (shrink)

This paper stresses the importance of identifying the nature of an author's conception of logic when using terms from modern logic in order to avoid, as far as possible, injecting our own conception of logic in the author's texts. Sundholm (2012. “‘Inference versus consequence” revisited: Inference, conditional, implication’, Synthese, 187, 943–956) points out that inferences are staged at the epistemic level and are made out of judgments, not propositions. Since it is now standard to read Aristotelian sullogismoi as inferences, I (...) have taken Alexander of Aphrodisias's commentaries to Aristotle's logical treatises as a basis for arguing that the premises and conclusions should be read as judgments rather than as propositions. Under this reading, when Alexander speaks of protaseis, we should not read the modern notion of proposition, but rather what we now call judgments. The point is not just a matter of terminology, it is about the conception of logic this terminology conveys. In this regard, insisting on judgments rather than on propositions helps bring to light Alexander's epistemic conception of logic. (shrink)

This paper focuses on an explanation in a newspaper article: why new European Union citizens will come to the UK from Eastern Europe (e.g., because of available jobs). Using a corpus-based method of analysis, I show how regular target readers have been positioned to generate premises in dialogue with the explanation propositions, and thus into an understanding of the explanation as an argument, one which contains a biased conclusion not apparent in the text. Employing this method, and in (...) particular ‘corpus comparative statistical keywords’, I show how two issues can be freshly looked at: implicit premise recovery; the argument/explanation distinction. (shrink)

Arguments, understood initially as premise-conclusion complexes of propositions, figure in our practices of giving reasons. Among other uses, we use arguments to advance reasons to explain why we believe or did something, to justify our beliefs or actions, to persuade others to do or to believe something, and (following Pinto 2001b) to advance reasons to worry or to fear that something is true. This book is about our uses of arguments to advance their premises as reasons for believing (...) their conclusions, i.e., as reasons for believing that their conclusions are true. The focus here is reason-giving centered on such reason-to-believe uses of arguments. Accordingly, the book does not discuss uses of arguments to advance their premises as reasons for believing that the conclusion is plausible, compelling, reasonable, nontrivial, helpful, plausibly deniable, or possible in principle. For ease of reference, hereafter I'll refer to uses of arguments to advance their premises as reasons for believing that their conclusions are true simply as reason-giving uses of argument. The book focuses on reason-giving uses of arguments that have three features, put briefly as follows. (shrink)

A detailed analysis of joint-contribution of premises and conclusions in classically valid sequents is presented in terms of hypergraphs. In (Saint-Germier, P., Verdée, P., & Villalonga, P. T. (2024). _Relevant entailment and logical ground. Philosophical Studies_ (pp. 1–43). https://doi.org/10.1007/s11098-024-02101-1 ), this idea of joint-contribution is introduced and motivated as a method for characterizing four kinds of relevant validity, in the sense of selecting the relevantly valid sequents among the classically valid sequents. The account in (Saint-Germier, P., Verdée, P., & Villalonga, (...) P. T. (2024). _Relevant entailment and logical ground. Philosophical Studies_ (pp. 1–43). https://doi.org/10.1007/s11098-024-02101-1 ) is built on a calculus, called \(\textsf{GLK}^{\hbox {a}}\), which proves grounding claims for (enthymematically) valid sequents. In the present paper an adequate representation of \(\textsf{GLK}^{\hbox {a}}\) is given in terms of hypergraphs. The hypergraphs are a kind of diagrammatic proofs for Classical Propositional Logic, entirely based on the grounds of premises and conclusions. The hypergraphs and their visualization provide insights into the relations between premises and conclusions and into the way validity is produced by the binding of premises and conclusions via their partial grounds. They visualize the network of elements of the sequent that contribute to its logical validity. Non-contributing (i.e. irrelevant) premises and conclusions are then specified to be those that are disconnected from the network, however one constructs the graphs. (shrink)

Accounts of arguments from expert opinion take it for granted that expert judgments count as (defeasible) evidence for propositions, and so an argument that proceeds from premises about what an expert judges to a conclusion that the expert is probably right is a strong argument. In Mizrahi (2013), I consider a potential justification for this assumption, namely, that expert judgments are significantly more likely to be true than novice judgments, and find it wanting because of empirical evidence (...) suggesting that expert judgments under uncertainty are not significantly more likely to be true than novice judgments or even chance. In this paper, I consider another potential justification for this assumption, namely, that expert judgments are not influenced by the cognitive biases novice judgments are influenced by, and find it wanting, too, because of empirical evidence suggesting that experts are vulnerable to pretty much the same cognitive biases that novices are vulnerable to. If this is correct, then the basic assumption at the core of accounts of arguments from expert opinion, namely, that expert judgments count as (defeasible) evidence for propositions, remains unjustified. (shrink)

Mercier and Sperber (MS) have ventured to undermine an age-old assumption in logic, namely the presence of premise-conclusion structures, in favor of two novel claims: that reasoning is an evolutionary product of a reason-intuiting module in the mind, and that theories of logic teach next to nothing about the mechanisms of how inferences are drawn in that module. The present paper begs to differ: logic is indispensable in formulating conceptions of cognitive elements of reasoning, and MS is no (...) less exempt from taking notice of premise-conclusion structures than the commonplace theories of reasoning are. Our counterclaim is realized in terms of diagrammatic reasoning dating back to Charles Peirce’s pragmaticism. The upshot is that pragmatist logic restores the premise-conclusion structures in argumentation, supplants reason-intuition module with logical content, and validates good reasoning as an indispensable resource evident to all rational minds that claim ownership of reason and understanding. (shrink)

This thesis mounts an attack against accounts of perceptual justification that attempt to analyze it in terms of evidential justifiers, and has defended the view that perceptual justification should rather be analyzed in terms of non-evidential justification. What matters most to perceptual justification is not a specific sort of evidence, be it experiential evidence or factive evidence, what matters is that the perceptual process from sensory input to belief output is reliable. I argue for this conclusion in the following (...) way. Chapter 1: The Arguments from HallucinationChapter 1 presents a skeptical argument from hallucination that starts from a premise about the alleged introspective indistinguishability of perception and hallucination, and concludes that perceptual knowledge is impossible. Underlying this argument are certain assumptions about the nature of perceptual justification, and different responses to the argument portray different views of perceptual justification. Evidentialism and dogmatism both reject the premise that appearances do not provide evidence sufficient for perceptual knowledge, although they disagree about the precise nature of the appearances. Epistemological disjunctivism rejects the premise that introspectively indistinguishable experiences provide the same evidence, while upholding the idea that some sort of evidence, namely factive evidence, is necessary for perceptual justification and knowledge. Process reliabilism rejects the premise that evidence is necessary for perceptual knowledge on the grounds that even perceptual justification can be obtained without evidence, as long as the cognitive process producing the belief is reliable.Chapter 2: EvidentialismChapter 2 starts by introducing some motivations for experientialist views of perceptual justification, such as evidentialism and dogmatism, which hold that conscious experiences evidentially justify perceptual beliefs. These motivations have to do with their ability to accommodate the New Evil Demon Intuition that demon-deceived subjects have justified perceptual beliefs and the Blindsight Intuition that blindsighters do not have justified perceptual beliefs. However, experientialist views are also faced with a Sellarsian dilemma: either experience is construed as non-propositional, but then the proposed evidential relation is unclear, or experience is construed as propositional, but then it is ad hoc to hold that they can evidentially justify without being justified themselves.Chapter 2 continues with a discussion of evidentialism, which grasps the first horn of this dilemma. I argue that evidentialism cannot adequately explain why a non-propositional experience constitutes evidence for this rather than that belief, and also does not provide any account of how to determine which belief fits an evidence-set which partly consists out of non-propositional experiences. Although a reliabilist version of evidentialism can provide a better account of these matters, it suffers from counter-intuitive predictions about justification and a conception of evidence that is so liberal that it could even include blindsighters and clairvoyants as having such evidence.Chapter 3: DogmatismChapter 3 focuses on variants of dogmatism, a theory of perceptual justification that grasps the second horn of the Sellarsian dilemma by holding that a perceptual experience with the content that p is sufficient for immediate prima facie justification of the belief that p. I first argue that dogmatism should identify perceptual experiences with high-level conscious states to accommodate the problem of novice vs. expert identification and the problem of the speckled hen. I then argue that this version of dogmatism still fails to meet a certain explanatory challenge which I dub the `Distinctiveness Problem'. Dogmatism should explain what is so distinctive about perceptual experience that enables it, in contrast with desire and imagination, to evidentially justify the belief that p without, in contrast with belief, being justified itself.Phenomenalist answers to this problem fail because they either do not provide a distinctive property of perceptual experience, or else provide a property that is reducible to or possibly caused by beliefs. In both cases, dogmatism would have the result that intuitively unjustifying experiences, such as imaginations, nevertheless become capable of justifying beliefs. Moreover, phenomenalists still need some explanation of why phenomenology is epistemically relevant at all.A new variant of the problem of the speckled hen is an intuitive illustration of this point against dogmatists. If a perceptual experience that p is not reliably connected to the fact that p or the belief that p, then beliefs based on this experience simply will not be intuitively justified. One possible response to this problem incorporates reliability into the content of experience in the sense that an experience cannot have the content that p if it is not reliably connected to both the fact that p and the belief that p. However, this will lose the motivation from the New Evil Demon Scenario, and will make large concessions towards reliabilism.Chapter 4: Epistemological DisjunctivismGiven these problems for experientialist views of perceptual justification, chapter 4 focuses on a different evidential account of justification: epistemological disjunctivism. According to the Justified True Belief version of Epistemological Disjunctivism, the fact that I see that p is the factive and reflectively accessible evidence in virtue of which I know that p. I argue that JTBED faces formidable problems: first, it cannot adequately deal with the basis problem, second, it cannot accommodate the New Evil Demon Intuition, third,it faces the problem of hyper-intellectualization, and fourth, it has no good account of reflective access.Knowledge First Epistemological Disjunctivism, in contrast, holds that seeing that p just is a way of knowing that p. The fact that I see that p constitutes my justification for believing that p, even though it is not necessary for my knowledge that p. Although this view solves most of the above problems, I argue that KFED still faces a challenge of its own: its notion of justification is so strong that justification entails knowledge but is not itself entailed by it. This means that it too faces a hyper-intellectualization objection because it cannot accommodate animal justification, and that it too will struggle to accommodate the New Evil Demon Intuition.Nevertheless, there is something to the epistemological disjunctivist idea that higher-order capabilities are important to perceptual justification. Specifically, higher-order capabilities provide one with a way of accommodating the Blindsight Intuition without appealing to the notion of experiential evidence: blindsighters are epistemically worse off than normal human perceivers because they lack higher-order beliefs about how they are gaining their information. If one holds that these higher-order beliefs provide a special sort of justification for perceptual beliefs, then blindsighters lack this type of justification. Chapter 5: Process ReliabilismAfter displaying the problems of several evidential accounts of perceptual justification, chapter 5 introduces a non-evidential account: process reliabilism. The classic version of this view holds that the reliability of a belief-forming process is necessary and sufficient for the prima facie justification of a specific set of beliefs, namely, those that arise out of belief-independent processes. Two classic major problems for this view consist of counterexamples to both the necessity and sufficiency of reliability for justification. Although the Generality Problem raises some difficulties for reliabilism, they do not appear to be insurmountable.The second part of chapter 5 focuses on a variety of process reliabilism, inferentialist reliabilism, that is explicitly aimed at responding to clairvoyance cases. According to inferentialist reliabilism, one should distinguish between basic and non-basic beliefs, where basic beliefs are those that result out of the non-inferential operation of an inferentially opaque cognitive system that developed in a natural way. Reliability is only sufficient for the justification of basic beliefs, while non-basic beliefs also require conditional reliability and justification of the beliefs on which they are based.This distinction between basic and non-basic beliefs is meant to answer the challenge arising out of clairvoyance cases because these are all supposedly cases in which the resulting beliefs arenon-basic. However, I argue that the beliefs in these cases come out as non-basic primarily because of the etiological constraint on cognitive systems, a constraint that is unfortunately undermotivated. It seems that beliefs can be justified even if they are produced by a cognitive system that developed by accident, or by a system that was artificially designed to produce those beliefs. So even though the inferentialist reliabilist might have a point in distinguishing between basic and non-basic beliefs, it is still in need of a different response to clairvoyance cases. Chapter 6: Rejoinders for ReliabilismChapter 6 improves on the inferentialist reliabilist account of justification by presenting a different way of dealing with the clairvoyance cases and New Evil Demon Scenario. I start from the empirically plausible idea that we know that we are perceiving when we are perceiving, not because of the use of experiential evidence, but rather, because of an unconscious source-monitoring mechanism. I then argue that the existence of such a source-monitoring mechanism could be used to explain why clairvoyance cases actually have to do with defeat rather than absence of prima facie justification: beliefs that pop up in our head should be recognized as stemming from untrustworthy sources, and so we acquire defeating higher-order beliefs about the first-order beliefs. I also argue that this defeat should be able to occur even if the higher-order beliefs are themselves unjustified. This defeater-account of clairvoyance is preferable to several externalist alternatives. Making reliability relative to a specific world seems rather ad hoc, and further requirements on justification, such as evidence-based belief, cognitively integrated belief, or properly produced belief, all appear unnecessary and are susceptible to adapted versions of the clairvoyance case.I further argue for an alternative inferentialist reliablist response to the New Evil Demon Intuition which treats it as mistaken rather than correct. The New Evil Demon Intuition might arise because of a mistaken view of actual perceptual justification as having to do with experiential evidence. This mistaken view could be explained by the fact that experience is actually reliably connected to belief and is often cited in response to a knowledge-challenge. If this is a correct analysis of the New Evil Demon Intuition, then there is an element of question-begging involved when this scenario is still pressed against inferentialist reliabilists who do not adhere to the experientialist assumption it presupposes.With the inferentialist reliabilist account in hand,we are able to see that many of the premises of the epistemological argument from hallucination are problematic. Evidence does not appear to be required for perceptual knowledge, as perceptual justification does not even require such evidence. Moreover, if we accept a reliabilist model of introspection, then we are often able to know on the basis of introspection that we are perceiving rather than hallucinating. Once one gets clear about the alternatives, it becomes apparent that the argument thrives on internalist assumptions about justification and knowledge that one need not accept. (shrink)

The article investigates the problem of the existence of the so-called multi-modal argu­ments – persuasive structures, where, along with written or spoken words, there are non-verbal elements that also perform persuasive functions. Such arguments are considered neither to be fully translatable into words, nor not to be total aliens in the argumentation studies. Along with the problem of translating the non-verbal component of a multi-modal argument, the question of their functional status in the structure of the argument is (...) also discussed. It is proposed to consider such elements as premises, the connection of which with the conclusion is explained through the description of the mode (whether it is an action, an image or a recorded audio message) in which their propositional con­tent is actualized. It is argued that the mode of the actualization of propositional content of the argument is no less significant than the content itself. On the basis of this claim it is proposed to consider “classical” textual arguments as a form of multi-modal arguments. (shrink)

Since the time of Aristotle's students, interpreters have considered Prior Analytics to be a treatise about deductive reasoning, more generally, about methods of determining the validity and invalidity of premise-conclusion arguments. People studied Prior Analytics in order to learn more about deductive reasoning and to improve their own reasoning skills. These interpreters understood Aristotle to be focusing on two epistemic processes: first, the process of establishing knowledge that a conclusion follows necessarily from a set of premises (that (...) is, on the epistemic process of extracting information implicit in explicitly given information) and, second, the process of establishing knowledge that a conclusion does not follow. Despite the overwhelming tendency to interpret the syllogistic as formal epistemology, it was not until the early 1970s that it occurred to anyone to think that Aristotle may have developed a theory of deductive reasoning with a well worked-out system of deductions comparable in rigor and precision with systems such as propositional logic or equational logic familiar from mathematical logic. When modern logicians in the 1920s and 1930s first turned their attention to the problem of understanding Aristotle's contribution to logic in modern terms, they were guided both by the Frege-Russell conception of logic as formal ontology and at the same time by a desire to protect Aristotle from possible charges of psychologism. They thought they saw Aristotle applying the informal axiomatic method to formal ontology, not as making the first steps into formal epistemology. They did not notice Aristotle's description of deductive reasoning. Ironically, the formal axiomatic method (in which one explicitly presents not merely the substantive axioms but also the deductive processes used to derive theorems from the axioms) is incipient in Aristotle's presentation. Partly in opposition to the axiomatic, ontically-oriented approach to Aristotle's logic and partly as a result of attempting to increase the degree of fit between interpretation and text, logicians in the 1970s working independently came to remarkably similar conclusions to the effect that Aristotle indeed had produced the first system of formal deductions. They concluded that Aristotle had analyzed the process of deduction and that his achievement included a semantically complete system of natural deductions including both direct and indirect deductions. Where the interpretations of the 1920s and 1930s attribute to Aristotle a system of propositions organized deductively, the interpretations of the 1970s attribute to Aristotle a system of deductions, or extended deductive discourses, organized epistemically. The logicians of the 1920s and 1930s take Aristotle to be deducing laws of logic from axiomatic origins; the logicians of the 1970s take Aristotle to be describing the process of deduction and in particular to be describing deductions themselves, both those deductions that are proofs based on axiomatic premises and those deductions that, though deductively cogent, do not establish the truth of the conclusion but only that the conclusion is implied by the premise-set. Thus, two very different and opposed interpretations had emerged, interestingly both products of modern logicians equipped with the theoretical apparatus of mathematical logic. The issue at stake between these two interpretations is the historical question of Aristotle's place in the history of logic and of his orientation in philosophy of logic. This paper affirms Aristotle's place as the founder of logic taken as formal epistemology, including the study of deductive reasoning. A by-product of this study of Aristotle's accomplishments in logic is a clarification of a distinction implicit in discourses among logicians--that between logic as formal ontology and logic as formal epistemology. (shrink)

In response to the claim that certain epistemically defective inferences such as Moore’s argument lead us to the conclusion that we ought to abandon closure, Crispin Wright suggests that we can avoid doing so by distinguishing it from a stronger principle, namely transmission. Where closure says that knowledge of a proposition is a necessary condition on knowledge of anything one knows to entail it, transmission makes a stronger claim, saying that by reasoning deductively from known premises one (...) can thereby acquire knowledge of or justification for the conclusion. Wright’s thought is that in cases such as Moore what is really going on is a failure of transmission, not a failure of closure. The problem with this claim is that it relies on an outdated formulation of closure which few nowadays would find plausible. Once we stipulate that it is the intuitive closure principle that deserves our attention, it becomes far less obvious that the project of diagnosing what is wrong with arguments such as Moore in terms of transmission failure but not closure failure can be vindicated. In order to demonstrate this claim, I consider intuitive closure of propositional justification vs. transmission of propositional justification and concede that perhaps these can come apart in the way that Wright suggests. I then argue that despite this concession, we also need an answer to the question of whether intuitive closure for doxastic justification and transmission for doxastic justification can come apart. We need an answer to this question because our ultimate interest in these issues stems from our interest in whether knowledge obeys closure, not merely whether propositional justification does. I argue that, even on the assumption that there is transmission failure of propositional justification, there is no transmission failure of doxastic justification. And if this is true, then there is no transmission failure of knowledge either. The transmission failure diagnosis of Moore’s argument and its ilk is thus in trouble. (shrink)

I criticize a case made by George Bowles for a certain theory pertaining to the evaluation of arguments on which the (degree of) attributed favourable relevance of an argument's premises to its conclusion is relevant to its evaluation, but nevertheless argue that such favourable relevance is indeed relevant to an argument's evaluation.

The aggregation of individual judgments on logically interconnected propositions into a collective decision on the same propositions is called judgment aggregation. Literature in social choice and political theory has claimed that judgment aggregation raises serious concerns. For example, consider a set of premises and a conclusion where the latter is logically equivalent to the former. When majority voting is applied to some propositions (the premises) it may give a different outcome than majority voting applied to another set of propositions (...) (the conclusion). This problem is known as the discursive dilemma (or paradox). The discursive dilemma is a serious problem since it is not clear whether a collective outcome exists in these cases, and if it does, what it is like. Moreover, the two suggested escape-routes from the paradox—the so-called premise-based procedure and the conclusion-based procedure—are not, as I will show, satisfactory methods for group decision-making. In this paper I introduce a new aggregation procedure inspired by an operator defined in artificial intelligence in order to merge belief bases. The result is that we do not need to worry about paradoxical outcomes, since these arise only when inconsistent collective judgments are not ruled out from the set of possible solutions. (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)

The aim of this paper is to show that central problems arising in the current debate about the nature of inferring can be solved by means of a predicative account of inference, which is inspired by Peter Hanks’s (2007, 2011, 2015) act-type theory of propositions. According to Hanks, the activity of judging is not the activity of assenting to an already structured content, but the activity of predicating a property of an object. The unity of the proposition is constituted (...) by this very activity, and propositions are understood as types of predicative acts. I will argue that we are able to formulate a new account of the activity of inferring on the basis of Hanks’s account of judgement and proposition. We are able to take an inference itself to be a complex kind of predicative activity if we understand the premises and the conclusion of an argument as judgements in Hanks’s sense. A valid (or invalid) argument can then be described as a type of predicative act. (Published Online: 04 May 2022). (shrink)

What is a good argument? That depends on what is meant by 'argument'. In formal logic, an argument is a set of sentences or propositions, one designated as conclusion and the remainder as premises. On this conception of argument, there are two kinds of goodness. An argument is good in a weak sense if the conclusion either follows deductively from the premises or receives strong evidential support from them. An argument is good (...) in a strong sense if, in addition to this, it has only true premises. Thus, in the strong sense, the paradigm of a good argument is a sound argument. (shrink)

An argument whose conclusion C is essential evidence for one of its premises can provide its target audience with justification for believing C. This is possible because we can enhance our justification for believing a proposition C by integrating it into an explanatory network of beliefs for which C itself provides essential evidence. I argue for this in light of relevant features of doxastic circularity, epistemic circularity, and explanatory inferences. Finally, I confirm my argument with an (...) example and respond to objections. (shrink)

Contrary to dictionaries, a non sequitur isn’t “any statement that doesn’t follow logically from previous statements”. Otherwise, every opening statement would be a non sequitur: a non sequitur is a statement claimed to follow from previous statements but that doesn’t follow. If the sentence making a given statement doesn’t contain ‘thus’, ‘so’, ‘hence’, ‘therefore’, or something else indicating an implication claim, the statement isn’t a non sequitur in this sense. But this is only one of several senses of that expression, (...) which, contrary to appearances, is a unitary common noun more properly written as one word: non-sequitur or nonsequitur. Above a nonsequitur was, roughly speaking, a conclusion of an invalid premise- conclusion argument, but not every such, only those that were stated to follow from premises that had been stated. Every informative proposition is the conclusion of an invalid argument. Anyway, nonsequiturs were not arguments. However, the expression ‘nonsequitur’ also means “invalid premise- conclusion argument”. It also means something like “fallacious reasoning” as in ‘Abe’s proof of the big-bang hypothesis is a nonsequitur’. The English noun is also used for an irrelevancy, an abrupt change of topic, or for any of many other expressions that are gratuitous, inappropriate, incongruous, or in some other way out of place. The English noun is derived from the Latin expression ‘non sequitur’, which is not a common noun but a sentence variously meaning “it isn’t in sequence ”, “it doesn’t follow”, “it is out of order”, etc. A statement that begins ‘in the second place’ is a nonsequitur if the previous sentence lacked implication of something like ‘in the first place’ or if it contained something similar to ‘in the third place’. In fact, a true implication claim can be a nonsequitur if there is no reason for making it. If Ben says ‘Hence, Abe swims and Abe swims’ in reply to Carl’s statement ‘Abe swims‘, then Ben may well be committing a nonsequitur. Many conversation stoppers are nonsequiturs. This lecture surveys and analyses a wide selection of uses of ‘nonsequitur’ in logic and logic-related literature. -/- END OF DRAFT 4 -/- NOTE 091215: When Rick Perry was discussing possible withdrawal from the race—unfortunately not the human race but the Republican race—a reporter reminded him that just last week Donald Trump predicted the Perry withdrawal. Perry interrupted with “A broken clock is right once a day”. -/- If you did not know Perry you might think his reply was a brilliant diversionary nonsequitur. If you know Perry you might think his reply was a stupid nonsequitur. -/- For the record, he did say ‘once a day’, not ‘twice a day’. BTW, my interjection ‘unfortunately not the human race but the Republican race’ was also a nonsequitur. (shrink)

To analyze the argument structure, the linked vs convergent distinction is crucial. In applying this distinction, argumentation scholars test for variations of argument strength under premise revision. A relevance-based test assesses whether an argument’s premises are individually relevant to its conclusion, while a support-based test assesses whether premises support the conclusion independently. Both criteria presuppose that evaluating an argument’s strength is methodologically prior to identifying its structure. Yet, if ‘argument structure’ is a (...) concept of analysis, then a structural analysis would precede evaluating an argument’s strength. We problematize that state-of-the-art methods to identify structures fail, because they rely on evaluative judgments, and so “put the cart before the horse.”. (shrink)

Besides pure declarative arguments, whose premises and conclusions are declaratives, and pure imperative arguments, whose premises and conclusions are imperatives, there are mixed-premise arguments, whose premises include both imperatives and declaratives, and cross-species arguments, whose premises are declaratives and whose conclusions are imperatives or vice versa. I propose a general definition of argument validity: an argument is valid exactly if, necessarily, every fact that sustains its premises also sustains its conclusion, where a fact sustains an imperative (...) exactly if it favors the satisfaction over the violation proposition of the imperative, and a fact sustains a declarative exactly if, necessarily, the declarative is true if the fact exists. I argue that this definition yields as special cases the standard definition of validity for pure declarative arguments and my previously defended definition of validity for pure imperative arguments, and that it yields intuitively acceptable results for mixed-premise and cross-species arguments. (shrink)

Arthur Prior’s argument for the A-theory of time in “Thank Goodness That’s Over” is perhaps his most famous and well-known non-logical work. Still, I think that this paper is one of his most misunderstood works. Because of this, much of its brilliance has yet to be properly appreciated. In this paper, I suggest that the explanation of this is that it has been treated as though it were following the standard model for a piece of Analytic philosophy. That is, (...) it has been assumed that what Prior was doing was deductively demonstrating the truth of a proposition which can be discussed via any sentences with the same semantic content. Here, I argue that this assumption is wrong on two fronts: Most importantly, the strongest reading of the structure of Prior’s argument is as an abduction rather than as a deduction. Many of the most important lessons of the argument are lost by focusing on the bare propositional content of its premise and conclusion statements. In other words, we can learn as much from the manner in which this argument is presented and expressed as we can from that which is expressed. (shrink)

This paper describes how bodily positions and gestures were used to teach argument diagramming to a student who cannot see. After listening to short argumentative passages with a screen reader, the student had to state the conclusion while touching his belly button. When stating a premise, he had to touch one of his shoulders. Premises lending independent support to a conclusion were thus diagrammed by a V-shaped gesture, each shoulder proposition going straight to the (...) class='Hi'>conclusion. Premises lending dependent support were diagrammed by a T-shaped gesture, the shoulder premises meeting at the collar bone before moving down to the belly button. Arguments involving two pairs of entailments were diagrammed by an I-shaped gesture, going from the collar bone to a mid-way conclusion above the abdomen before travelling to the final conclusion at the belly button. The student’s strong performance suggests that placing propositions at different locations on the body and uniting them with gestures can help one discern correct argumentative structures. (shrink)

Consider the following. The first is a one-premise argument; the second has two premises. The question sign marks the conclusions as such. -/- Matthew, Mark, Luke, and John wrote Greek. ? Every evangelist wrote Greek. -/- Matthew, Mark, Luke, and John wrote Greek. Every evangelist is Matthew, Mark, Luke, or John. ? Every evangelist wrote Greek. -/- The above pair of premise-conclusion arguments is of a sort familiar to logicians and philosophers of science. In each case (...) the first premise is logically equivalent to the set of four atomic propositions: “Matthew wrote Greek”, “Mark wrote Greek”, “Luke wrote Greek”, and “John wrote Greek”. The universe of discourse is the set of evangelists. We presuppose standard first-order logic. -/- As many logic texts teach, the first of these two premise-conclusion arguments—sometimes called a complete enumerative induction— is invalid in the sense that its conclusion does not follow from its premises. To get a counterargument, replace ‘Matthew’, ‘Mark’, ‘Luke’, and ‘John’ by ‘two’,’four’, ‘six’ and ‘eight’; replace ‘wrote Greek’ by ‘are even’; and replace ‘evangelist’ by ‘number’. This replacement converts the first argument into one having true premises and false conclusion. -/- But the same replacement performed on the second argument does no such thing: it converts the second premise into the falsehood “Every number is two, four, six, or eight”. As many logic texts teach, there is no replacement that converts the second argument into one with all true premises and false conclusion. The second is valid; its conclusion is deducible from its two premises using an instructive natural deduction. -/- This paper “does the math” behind the above examples. The theorem could be stated informally: the above examples are typical. (shrink)

In argumentation, metaphors are often considered as ambiguous or deceptive uses of language leading to fallacies of reasoning. However, they can also provide useful insights into creative argumentation, leading to genuinely new knowledge. Metaphors entail a framing effect that implicitly provides a specific perspective to interpret the world, guiding reasoning and evaluation of arguments. In the same vein, emotions could be in sharp contrast with proper reasoning, but they can also be cognitive processes of affective framing, influencing our reasoning and (...) behavior in different meaningful ways. Thus, a double (metaphorical and affective) framing effect might influence argumentation in the case of emotive metaphors, such as “Poverty is a disease” or “Your boss is a dictator,” where specific “emotive words” (disease, dictator) are used as vehicles. We present and discuss the results of two experimental studies designed to explore the role of emotive metaphors in argumentation. The studies investigated whether and to what extent the detection of a fallacious argument is influenced by the presence of a conventional vs. novel emotive metaphor. Participants evaluated a series of verbal arguments containing either “non-emotive” or “emotive” (positive or negative) metaphors as middle terms that “bridge” the premises of the argument. The results show that the affective coherence of the metaphor's vehicle and topic plays a crucial role in participants' reasoning style, leading to global heuristic vs. local analytical interpretive processes in the interplay of the metaphorical and the affective framing effects. (shrink)

One innovation in this paper is its identification, analysis, and description of a troubling ambiguity in the word ‘argument’. In one sense ‘argument’ denotes a premise-conclusion argument: a two-part system composed of a set of sentences—the premises—and a single sentence—the conclusion. In another sense it denotes a premise-conclusion-mediation argument—later called an argumentation: a three-part system composed of a set of sentences—the premises—a single sentence—the conclusion—and complex of sentences—the mediation. The latter (...) is often intended to show that the conclusion follows from the premises. The complementarity and interrelation of premise-conclusion arguments and premise-conclusion-mediation arguments resonate throughout the rest of the paper which articulates the conceptual structure found in logic from Aristotle to Tarski. This 1972 paper can be seen as anticipating Corcoran’s signature work: the more widely read 1989 paper, Argumentations and Logic, Argumentation 3, 17–43. MR91b:03006. The 1972 paper was translated into Portuguese. The 1989 paper was translated into Spanish, Portuguese, and Persian. (shrink)

Abstract In this essay, I will argue that images can play a substantial role in argumentation: exploiting information from the context, they can contribute directly and substantially to the communication of the propositions that play the roles of premises and conclusion. Furthermore, they can achieve this directly, i.e. without the need of verbalization. I will ground this claim by presenting and analyzing some arguments where images are essential to the argumentation process. Content Type Journal Article Pages 1-14 DOI 10.1007/s10503-011-9259-y (...) Authors Axel Arturo Barceló Aspeitia, Instituto de Investigaciones Filosóficas, Universidad Nacional Autónoma de México, Cto. Mario de la Cueva s/n, Cd. Universitaria, Coyoacán, 04500 DF, Mexico Journal Argumentation Online ISSN 1572-8374 Print ISSN 0920-427X. (shrink)

Trenton Merricks argues that we need propositions to serve as the premises and conclusions of modally valid arguments (Merricks 2015). A modally valid argument is an argument in which, necessarily, if the premises are true, then the conclusion is also true. According to Mer- ricks, the premises and conclusions of modally valid arguments have their truth conditions essentially, and they exist necessarily. Sentences do not satisfy these conditions. Thus, we need propositions. Merricks’ argument adds a new (...) chapter to the longstanding debate over the exis- tence of propositions. However, I argue that Merricks’ argument does not quite succeed. Merricks has overlooked one viable alternative to pos- tulating propositions. However, this alternative employs the relation of being true-at-a-world, which is difficult to analyze. Thus, the soundness of Merricks’ argument ultimately depends on the comparative merits of accepting propositions as abstract entities, versus accepting truth-at-a- world as an unanalyzed relation between sentences and possible worlds. (shrink)

An increasingly popular view in contemporary epistemology holds that the most fundamental norm governing belief is knowledge. According to this norm one shouldn’t believe what one doesn’t know. A prominent argument for the knowledge norm appeals to the claim that knowledge is the most general condition of epistemic assessment of belief, one entailing all other conditions under which we epistemically assess beliefs. This norm would provide an easy and straightforward explanation of why we assess beliefs along all these various (...) epistemic dimensions. This article argues that this line of argument is ultimately unsuccessful. I show that the main premise of the argument actually supports the opposite conclusion: the norm of belief requires a condition weaker than knowledge. Furthermore, I argue that if we hold on to the assumption that knowledge is the most general condition of belief’s epistemic assessment, the fundamental norm of belief is factive: one is not permitted to believe a proposition p if it is not true that p. (shrink)

It is one thing for a given proposition to follow or to not follow from a given set of propositions and it is quite another thing for it to be shown either that the given proposition follows or that it does not follow.* Using a formal deduction to show that a conclusion follows and using a countermodel to show that a conclusion does not follow are both traditional practices recognized by Aristotle and used down through the (...) history of logic. These practices presuppose, respectively, a criterion of validity and a criterion of invalidity each of which has been extended and refined by modern logicians: deductions are studied in formal syntax (proof theory) and coun¬termodels are studied in formal semantics (model theory). The purpose of this paper is to compare these two criteria to the corresponding criteria employed in Boole’s first logical work, The Mathematical Analysis of Logic (1847). In particular, this paper presents a detailed study of the relevant metalogical passages and an analysis of Boole’s symbolic derivations. It is well known, of course, that Boole’s logical analysis of compound terms (involving ‘not’, ‘and’, ‘or’, ‘except’, etc.) contributed to the enlargement of the class of propositions and arguments formally treatable in logic. The present study shows, in addition, that Boole made significant contributions to the study of deduc¬tive reasoning. He identified the role of logical axioms (as opposed to inference rules) in formal deductions, he conceived of the idea of an axiomatic deductive sys¬tem (which yields logical truths by itself and which yields consequences when ap¬plied to arbitrary premises). Nevertheless, surprisingly, Boole’s attempt to imple¬ment his idea of an axiomatic deductive system involved striking omissions: Boole does not use his own formal deductions to establish validity. Boole does give symbolic derivations, several of which are vitiated by “Boole’s Solutions Fallacy”: the fallacy of supposing that a solution to an equation is necessarily a logical consequence of the equation. This fallacy seems to have led Boole to confuse equational calculi (i.e., methods for gen-erating solutions) with deduction procedures (i.e., methods for generating consequences). The methodological confusion is closely related to the fact, shown in detail below, that Boole had adopted an unsound criterion of validity. It is also shown that Boole totally ignored the countermodel criterion of invalid¬ity. Careful examination of the text does not reveal with certainty a test for invalidity which was adopted by Boole. However, we have isolated a test that he seems to use in this way and we show that this test is ineffectual in the sense that it does not serve to identify invalid arguments. We go beyond the simple goal stated above. Besides comparing Boole’s earliest criteria of validity and invalidity with those traditionally (and still generally) employed, this paper also investigates the framework and details of THE MATHEMATICAL ANALYSIS OF LOGIC. (shrink)

In the present article we attempt to show that Aristotle's syllogistic is an underlying logiC which includes a natural deductive system and that it isn't an axiomatic theory as had previously been thought. We construct a mathematical model which reflects certain structural aspects of Aristotle's logic. We examine the relation of the model to the system of logic envisaged in scattered parts of Prior and Posterior Analytics. Our interpretation restores Aristotle's reputation as a logician of consummate imagination and skill. Several (...) attributions of shortcomings and logical errors to Aristotle are shown to be without merit. Aristotle's logic is found to be self-sufficient in several senses: his theory of deduction is logically sound in every detail. (His indirect deductions have been criticized, but incorrectly on our account.) Aristotle's logic presupposes no other logical concepts, not even those of propositional logic. The Aristotelian system is seen to be complete in the sense that every valid argument expressible in his system admits of a deduction within his deductive system: every semantically valid argument is deducible. (shrink)

In order to reply to the contemporary skeptic’s argument for the conclusion that we don’t have any empirical knowledge about the external world, several authors have proposed different fallibilist theories of knowledge that reject the epistemic closure principle. Holliday, 1–62 2015a), however, shows that almost all of them suffer from either the problem of containment or the problem of vacuous knowledge or both. Furthermore, Holliday suggests that the fallibilist should allow a proposition to have multiple sets of (...) relevant alternatives, each of which is sufficient while none is necessary, if all its members are eliminated, for knowing that proposition. Not completely satisfied with Holliday’s multi-path reply to the skeptic, the author suggests a new single-path relevant-possibility theory of knowledge and argues that it can avoid both the problem of containment and the problem of vacuous knowledge of a certain sort while rejecting skepticism about the external world. (shrink)

This article offers a logical analysis of Slippery Slope Arguments. Such arguments claim that adopting a certain act or policy would take us down a slippery slope to an undesirable bottom and infer from this that we should refrain from this act or policy. Even though a logical assessment of such arguments has not received much careful attention, it is of vital importance to their overall assessment because if the premises fail to support the conclusion an argument is (...) worthless. I partition slippery slope reasoning by means of two dichotomies (reasoning under certainty vs. uncertainty and one-step vs. multiple-step reasoning) into four general categories and evaluate these in turn. The analysis reveals that slippery slope arguments are logically fallacious. (shrink)

Critical thinking and arguments -- What makes a good argument? -- Premises and conclusions -- Language -- Propositional arguments -- Categorical arguments -- Analogical arguments -- Statistical arguments -- Causal arguments -- Moral arguments -- Answers to selected exercises -- Reference guide.

Richard Swinburne (Swinburne and Shoemaker 1984; Swinburne 1986) argues that human beings currently alive have non{bodily immaterial parts called souls. In his main argument in support of this conclusion (modal argument), roughly speaking, from the assumption that it is logically possible that a human being survives the destruction of their body and a few additional premises, he infers the actual existence of souls. After a brief presentation of the argument we describe the main known objection to (...) it, called the substitution objection (SO for short), which is raised by Alston and Smythe (1994), Zimmerman (1991) and Stump and Kretzmann (1996). We then explain Swinburne's response to it (1996). This constitutes a background for the discussion that follows. First, we formalize Swinburne's argument in a quantified propositional modal language so that it is logically valid and contains no tacit assumptions, clearing up some notational issues as we go. Having done that, we explain why we find Swinburne's response unsatisfactory. Next, we indicate that even though SO is quite compelling (albeit for a slightly different reason than the one given previously in the literature), a weakening of one of the premises yields a valid argument for the same conclusion and yet immune to SO. Even this version of the argument, we argue, is epistemically circular. (shrink)

In "The Self-Defeating Character of Skepticism," Douglas C. Long presents a transcendental argument against epistemological skepticism.' The argument has a distinctively Kantian flavor (though Long does not highlight this connection), in that it proceeds from the premise that I have self-knowledge and ends with the conclusion that I have perceptual knowledge of an objective, material subject of mental states. If the skeptic wishes to accept the transcendental argument's premise (as he seems to do), then (...) he must reject his claim that I lack knowledge of all propositions concerning my physical nature, history and environment. The falsity of this skeptical claim is a condition for the possibility of self-knowledge, according to Long's transcendental argument. In this paper, I would like to see whether the argument is really work-able. (shrink)

Empty names are a problem for Russellians. I describe three ways to approach solving the problem. These are positing gappy propositions as contents, nonsingular propositions as contents, or denying that sentences containing empty names have contents. I discuss methods for deciding between solutions. I then argue for some methods over others and defend one solution using those methods. I reject the arguments that either intuitions about truth value, truth, content, or meaningfulness can decide between the solutions. I give an alternative (...) argument which does decide between the three solutions. The alternative is based on the idea that a sentence and its internal negation are contrary: they cannot both be true, but they might both be false. I argue from Russellian premises to the conclusion that such sentences cannot be assigned truth values when they contain empty names. The argument shows that no Russellian should assign a truth value to a sentence containing an empty name, and therefore that no Russellian should assign a proposition as the content of such a sentence. This shows that Russellians should conclude that sentences containing empty names do not have contents, i.e. the no proposition view. (shrink)

In this paper, I inspect the grounds for the mature Spinozist argument for substance monism. The argument is succinctly stated at Ethics Part 1, Proposition 14. The argument appeals to two explicit premises: (1) that there must be a substance with all attributes; (2) that substances cannot share their attributes. In conjunction with a third implicit premise, that a substance cannot not have any attribute whatsoever, Spinoza infers that there can be no more than one (...) substance. I begin the inspection with the analysis of the first premise, which is provided in the form of the four proofs of God’s existence in Ethics Part 1, Proposition 11. While demonstrating how Spinoza adopts a progressive approach, where the fourth proof of God’s existence is more successful and persuasive than the third, which is more successful than the second, etc., I also unpack concepts central to Spinoza’s thinking here, including the concepts of reason (ratio) and power (potesta or potentia). I then analyze the second premise of the Spinozist argument for substance monism, as established by Ethics Part 1, Proposition 4 in conjunction with Ethics Part 1, Proposition 5. I take up and respond to the objection attributed to Leibniz that a substance p can have the attributes x and y and a substance q can have the attributes y and z, and thus that substances can share some attributes while remaining distinct. Throughout the study, my attention is focused on the argumentative procedures Spinoza adopts. This yields a close, internalist reading of the text where Spinoza effectively embraces substance monism. In conclusion to this study, I underscore to the originality of Spinoza’s argument for seventeenth century theories of substance. (shrink)

Legal analysis is dominated by legal arguments, and the assessment of any legal claim requires the assessment of the strengths and weaknesses of those arguments. The ‘logocratic’ method is a systematic method for assessing the strengths and weaknesses of arguments. More specifically, it is a method designed to help the analyst determine what degree of warrant the premises of an argument provide for its conclusion. Although the method is applicable to any type of argument, this essay focuses (...) on the logocratic framework for assessing the strengths and weaknesses of evidentiary legal arguments, arguments offered in litigation in which evidentiary propositions are proffered to support hypotheses. The focus is on American law, but the logocratic analysis offered here could be adjusted without much trouble to handle arguments about evidence in other systems of litigation. In any legal system that aspires to have a fact-finding process that is sufficiently reliable to meet the requirements of justice, we might fashion an analogue for the Socratic maxim ‘the unexamined life is not worth living’: the unexamined evidentiary argument is not worth believing. The logocratic method seeks to help the evidence analyst pursue that Socratic mission, tailored to the rules and institutions of evidence law. (shrink)

Although in some contexts the notions of an ordinary argument’s presumption, assumption, and presupposition appear to merge into the one concept of an implicit premise, there are important differences between these three notions. It is argued that assumption and presupposition, but not presumption, are basic logical notions. A presupposition of an argument is best understood as pertaining to a propositional element (a premise or the conclusion) e of the argument, such that the presupposition is (...) a necessary condition for the truth of e or for a term in e to have a referent. In contrast, an assumption of an argument pertains to the argument as a whole in that it is integral to the reasoning or inferential structure of the argument. A logical assumption of an argument is essentially a proposition that must be true in order for the argument aside from that proposition to be fully cogent. Nothing that is both comparable and distinguishing can be said about presumptions of arguments. Rather, presumptions of arguments are distinctively conventional; they are introduced through conventional rules (e.g., those that concern how to treat promises). So not all assumptions and not all presuppositions of arguments are presumptions of those arguments, although all presumptions of arguments are either assumptions or presuppositions of those arguments. This account avoids making the (monological) notion of presumption vacuous and dissolving the distinction between assumption and presumption, which is a vulnerability of alternative views such as Hansen’s and Bermejo-Luque’s, as is shown. (shrink)

Cappelen and Lepore (2005) maintain that Incompleteness Arguments for context sensitivity are fallacious. In their view, Incompleteness Arguments are non sequitur fallacies whose conclusions are not logically related to premises. They affirm that the conclusions of Incompleteness Arguments are metaphysical claims about the existence of entities that might be constituents of propositions, while their premises concern psychological data about speakers' dispositions to truth evaluate sentences in contexts of utterance. Cappelen and Lepore reject Incompleteness Arguments because psychological data have no bearing (...) on metaphysical issues. I do not dispute Cappelen and Lepore's claim that psychological data have no relevance to metaphysics. Nonetheless, I argue that Cappelen and Lepore's criticism is vitiated by a misunderstanding of the nature of Incompleteness Arguments that makes them overlook the link between semantics and linguistic competence. I try to shed light on the real nature of Incompleteness Arguments by pointing at the failure of Cappelen and Lepore's criticism. My aim is not to defend Semantic Contextualism, but to bring to attention the link between semantics and linguistic competence that should never be overlooked in debates in the field of semantics. (shrink)

In Tractatus 5.132 Wittgenstein argues that inferential justification depends solely on the understanding of the premises and conclusion, and is not mediated by any further act. On this basis he argues that Frege’s and Russell’s rules of inference are “senseless” and “superfluous”. This line of argument is puzzling, since it is unclear that there could be any viable account of inference according to which no such mediation takes place. I show that Wittgenstein’s rejection of rules of inference can (...) be motivated by taking account of his holistic construal of the relation between inference and understanding. (shrink)

Our ability to think, argue and reason is determined by our ability to question. Questions are a vital component of critical thinking, yet we underestimate the role they play. Using Questions to Think puts questioning back in the spotlight. -/- Naming the parts of questions at the same time as we name parts of thought, this one-of-a-kind introduction allows us to see how questions relate to the definitions of propositions, premises, conclusions, and the validity of arguments. Why is this important? (...) Making the role of questions visible in thinking, reasoning, and dialogue, allows us to: -/- - Ask better questions - Improve our capability to understand an argument - Exercise vigilance in the act of questioning - Make explicit what you already know implicitly - Engage with ideas that contradict our own - See ideas in broader context -/- Breathing new life into our current approach to critical thinking, this practical, much-needed textbook moves us away from the traditional focus on formal argument and fallacy identification, combines the Kantian critique of reason with Hans-Georg Gadamer's hermeneutics and reminds us why thinking can only be understood as an answer to a question. (shrink)

Harming other people is prima facie wrong. Unless we can be very certain that doing so is justified under the circumstances, we ought not to do it. In this paper, I argue that we ought to dismantle harsh retributivist criminal justice systems for this reason; we cannot be sufficiently certain that the harm is justified. Gregg Caruso, Ben Vilhauer and others have previously argued for the same conclusion; however, my own version sidesteps certain controversial premises of theirs. Harsh retributivist (...) criminal justice can only be morally right if the following three propositions are true: Moral responsibility exists, retributivism is right, and we can find out how much punishment offenders deserve for their crimes. Suppose that we initially assign a high credence to each of the three propositions; I assume for the sake of argument that there are good arguments in support of each. Nevertheless, these arguments ultimately depend on intuitions. Since we have philosophical peers whose intuitions differ from ours, we ought to downgrade our credence in each. However, even slightly less credence in each proposition means far less credence in a conjunction of all three. Since the stakes are high and there are morally safer options for a criminal justice system, we ought to dismantle harsh retributivist ones. (shrink)

I argue for the claim that if Lewis’s regularity theory of laws were true, we could not know any positive law statement to be true. Premise 1: According to that theory, for any law statement true of the actual world, there is always a nearby world where the law statement is false (a world that differs with respect to one matter of particular fact). Premise 2: One cannot know a proposition to be true if it is false (...) in a nearby world (the epistemological safety principle). The conclusion that no law statement can be known to be true follows immediately from the two premises. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Kinship:The Relationship Between Johnstone's Ideas about Philosophical Argument and the Pragma-Dialectical Theory of ArgumentationFrans H. van Eemeren and Peter Houtlosser1. Johnstone on the Nature of Philosophical ArgumentAs he himself declared in Validity and Rhetoric in Philosophical Argument (1978, 1), the late philosopher Henry W. Johnstone Jr. devoted a long period of his professional life to clarifying the nature of philosophical argument. His well-known view was that (...) philosophical arguments are sui generis, i.e., not to be judged by the standards of argumentation in science or everyday discourse. Philosophical arguments are not ad rem, but are based on premises that are expressed or implied commitments of a party in dialogue. This is why philosophical argumentation is, according to Johnstone, always ad hominem. In philosophical argumentation, every ad rem argument begs the question.Usually, ad hominem argumentation is dismissed as invalid. Johnstone, however, maintains that making use of argumentum ad hominem is the only way to establish a philosophical conclusion. In an argumentum ad hominem, inferences are drawn from propositions stated or implied by the other party and critical questions are raised about the conclusions that were drawn, so that it can be used to refute a philosophical position by showing that this position is inconsistent. As Walton (2001) rightly observes, this type of ad hominem argumentation boils down to arguing from commitments of the other party, i.e., ex concessis.The use of ad hominem argumentation as the criticism of a position in terms of its own presuppositions is, in Johnstone's view, the only valid argument in philosophy, if any philosophical argument is indeed valid. All philosophical polemic is in this perspective in fact addressed ad hominem. This applies not only to philosophical argumentation that concerns self-referential refutation but also to other ad hominem types of philosophical argumentation, including the tu quoque argument (1978, 11–12).According to Johnstone, there is no objective criterion for determining the validity of ad hominem argumentation. Validity must, says Johnstone in the [End Page 51] epilogue of his collected essays on philosophical argument, be viewed as "a regulative ideal" (135). Much earlier, Johnstone had already come to the conclusion that "the valid argument is the one that maintains philosophical discussion" (38). It is this self-perpetuating feature that is the distinctive rationality of philosophy. By forcing the interlocutor to elaborate his philosophical position rather than just repeat it, the gap between the interlocutors is bridged.In order to distinguish between constructive persuasive argumentation and mere repetition or other forms of paralyzing the discourse, the line must be drawn between responsible and irresponsible persuasion. This is a problem for Johnstone. Where the Ancients solved the problem by insisting that the persuader be virtuous, Johnstone proposed to base the distinction between responsible and irresponsible persuasion on the attitude of the philosopher and his interest in maintaining the philosophical enterprise. The philosopher is a critic who criticizes con amore. His intention to do so, however, is revealed "only in the way he goes about his work" (84).A more down to earth criterion for responsible persuasion that Johnstone proposed is that the discourse should not tend to degenerate. Logic, as the discipline concerned with reason, serves to prevent the discussion from degenerating, but it can do so only if the parties concerned have jointly committed themselves to certain logical principles. If in philosophical argument a defendant is under no obligation to acknowledge an inconsistency when the other party points out an inconsistency in his position, then the other party's criticism cannot count as valid. According to Johnstone, however, it will depend on the parties' presuppositions whether or not they consider two statements as being inconsistent. In other words, what is inconsistent for the one party may not be inconsistent for the other party.Few obligations are imposed on everyone; most obligations arise from commitments made by specific individuals or groups of individuals. As Johnstone says, "Even the cogent philosophical argument is not, of course, absolutely cogent; it is cogent only relatively to interlocutors who maintain the premises on which it depends" (27). Once we abandon the search for objective conditions under which philosophical arguments can be valid, according... (shrink)