This book proposes guidelines for constructing and evaluating definitions of terms, i.e. words or phrases of general application. The guidelines extend to adoption of nomenclature. The book is meant to be a practical guide for people who find themselves in their daily lives or their employment producing or evaluating definitions of terms. It can be consulted rather than being read through. The book’s theoretical framework is a distinction, due to Robert H. Ennis, of three dimensions of definitions: the act of (...) the definer, the content of the definition, and its form. The act of a definer is what the definer does in defining a term; the book distinguishes, following Ennis, three basic acts of defining: reporting, stipulating, and advocating. The content of a definition is in one sense the information that the definition conveys and in another sense the words in its defining part. The form of a definition is the way it is expressed, for example as a definition by genus and differentia. (shrink)

This book brings together in one place David Hitchcock’s most significant published articles on reasoning and argument. In seven new chapters he updates his thinking in the light of subsequent scholarship. Collectively, the papers articulate a distinctive position in the philosophy of argumentation. Among other things, the author:• develops an account of “material consequence” that permits evaluation of inferences without problematic postulation of unstated premises.• updates his recursive definition of argument that accommodates chaining and embedding of arguments and allows any (...) type of illocutionary act to be a conclusion. • advances a general theory of relevance.• provides comprehensive frameworks for evaluating inferences in reasoning by analogy, means-end reasoning, and appeals to considerations or criteria.• argues that none of the forms of arguing ad hominem is a fallacy.• describes proven methods of teaching critical thinking effectively. (shrink)

In many actual arguments, the conclusion seems intuitively to follow from the premisses, even though we cannot show that it follows logically. The traditional approach to evaluating such arguments is to suppose that they have an unstated premiss whose explicit addition will produce an argument where the conclusion does follow logically. But there are good reasons for doubting that people so frequently leave the premisses of their arguments unstated. The inclination to suppose that they do stems from the belief that (...) the only way in which an argument's conclusion can follow definitely from its premisses is to follow logically. I argue that this belief is mistaken. I propose a revision of the current generic conception of logical consequence, and its variant specifications, to avoid the paradoxes of strict implication. The revised conception can then be naturally extended to include also what we might call 'enthymematic consequence'. This concept is a kind of consequence, whose properties merit investigation. (shrink)

In The Uses of Argument, Stephen Toulmin proposed a model for the layout of arguments: claim, data, warrant, qualifier, rebuttal, backing. Since then, Toulmin’s model has been appropriated, adapted and extended by researchers in speech communications, philosophy and artificial intelligence. This book assembles the best contemporary reflection in these fields, extending or challenging Toulmin’s ideas in ways that make fresh contributions to the theory of analysing and evaluating arguments.

Informal logic is a new sub-discipline of philosophy, roughly definable as the philosophy of argument. Contributors have challenged the traditional concept of an argument as a premiss-conclusion complex, in favour of speech-act, functional and dialogical conceptions; they have identified as additional components warrants, modal qualifiers, rebuttals, and a dialectical tier. They have objected that "soundness" is neither necessary nor sufficient for a good argument. Alternative proposals include acceptability, relevance and sufficiency of the premisses; conformity to a valid argument schema; conformity (...) to rules for discussion aimed at rational resolution of a dispute. Informal logic is a significant part of philosophy. (shrink)

A conclusion follows from given premisses if and only if an acceptable counterfactual-supporting covering generalization of the argument rules out, either definitively or with some modal qualification, simultaneous acceptability of the premisses and non-accepta-bility of the conclusion, even though it does not rule out acceptability of the premisses and does not require acceptability of the conclusion independently of the premisses. Hence the reiterative associated conditional of an argument is true if and only it has such a covering generalization, and a (...) supposed unexpressed premiss supplied to make an argument formally valid should be a covering generalization. (shrink)

I propose some changes to the conceptions of argument and of argumentative discussion in Ralph Johnson's Manifest Rationality (2000). An argument is a discourse whose author seeks to persuade an audience to accept a thesis by producing reasons in support of it and discharging his dialectical obligations. An argumentative discussion (what Johnson calls ‘argumentation’) is a sociocultural activity of constructing, presenting, interpreting, criticizing, and revising arguments for the purpose of reaching a shared rationally supported position on some issue. Johnson's theory (...) of argumentative discussion, with occasional modifications, is derived from this definition as a sequence of 17 theorems. Argumentative discussion is a valuable cultural practice; it is the most secure route to correct views and wise policies. (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)

Wellman’s “conduction” and Govier’s “conductive arguments” are best described as appeals to considerations. The considerations cited are features of a subject of interest, and the conclusion is the attribution to it of a supervenient status like a classification, an evaluation, a prescription or an interpretation. The conclusion may follow either conclusively or non-conclusively or not at all. Weighing the pros and cons is only one way of judging whether the conclusion follows. Further, the move from in-formation about the subject’s cited (...) features to the attribution of a supervenient status is often but one moment in a more complex process. (shrink)

An appeal to features of some case in support of attribution of some status to that case is non-conclusively valid if and only if it is not conclusively valid but any case with those features either has the status or has some overriding negatively relevant feature not implied by lacking the status.

Some solo verbal reasoning serves the function of arriving at a correct answer to a question from information at the reasoner’s disposal. Such reasoning is good if and only if its grounds are justified and adequate, its warrant is justified, and the reasoner is justified in assuming that no defeaters apply. I distinguish seven sources of justified grounds and state the conditions under which each source is trustworthy. Adequate grounds include all good relevant information practically obtainable by the reasoner. The (...) claim must follow from the grounds in accordance with a justified general warrant. If this warrant is not universal, the reasoner must be justified in assuming that no exception-making circumstances hold in the particular case to which it is applied. (shrink)

In his Fallacies, Hamblin (1970) castigated what he called the “standard treatment” of fallacies in introductory textbooks of his day as debased, worn-out, dogmatic, and unconnected to anything else in modern logic. A bit more than 50 years later, I investigate the treatment of fallacies in six English-language introductory textbooks with a section on fallacies that have gone into 10 or more editions, to see whether their treatment of fallacies has taken account of the scholarship on fallacies that Hamblin’s book (...) evoked and is better than the treatment that Hamblin described. The answer is: not much. I conclude by setting out criteria for an adequate treatment of fallacies in an introductory textbook. (shrink)

The epistemologist John Pollock has implemented computationally an architecture for a rational agent which he calls OSCAR. OSCAR models both practical and theoretical (or epistemic) reasoning. I argue that Pollock's model of practical reasoning, which has seven components, is superior not only to the two-component belief-desire model stemming from Aristotle, but also to the three-component belief-desire-intention model developed especially by Michael Bratman. Despite its advantages, Pollock's model of practical reasoning is incomplete in at least three respects: it is solipsistic, it (...) is egoistic and it is unsocial. (shrink)

I argue, contrary to a recent assertion by Lilian Bermejo-Luque, that the inference-claim in an argument of the form ‘p, so q’ is not its associated material conditional ‘if p then q’. Rather, it is the claim that the argument has a covering generalization that is non-trivially true. I defend this interpretation against three objections by Bermejo-Luque.

278 non-freshman university students taking a l2-week critical thinking course in a large single-section class, with computer-assisted guided practice as a replacement for small-group discussion, and all testing in machine-scored multiple-choice format, improved their critical thinking skills, as measured by the California Critical Thinking Skills Test, by half a standard deviation, a moderate improvement. The improvement was more than that reported with a traditional format without computer-assisted instruction, but less than that reported with a format using both computer-assisted instruction and (...) essay-type assignments. Further studies are needed to test hypotheses suggested by these results. (shrink)

The correspondence about the German translation of Tarski’s truth monograph shows that he initiated four changes to the Polish original: a new title, a postscript, a historical note, and a change in one sentence. The new title is a more accurate description of the work’s content. The postscript updates Tarski’s main results by abandoning Husserl’s theory of semantic categoriesSemantic categories, theory of as a constraint on the structure of formalized languages and by allowing variables in a language to be of (...) transfinite order; it thus replaces Tarski’s initial partly negative result with a uniformly positive result, and at the same time makes much of the original work obsolete. The historical note addresses an experience whose unpleasantness Tarski felt to the end of his life—the implication in a footnote of a paper by Rudolf CarnapCarnap, Rudolf that his investigations on truth were derivative from Gödel’sGödel, Kurt work on the incompleteness of Principia MathematicaPrincipia Mathematica and related systems. The change in the sentence is substantive but minor. (shrink)

I describe and evaluate Harald Wohlrapp’s proposal in The Concept of Argument that we should see reasonable argumentation as guided by the “principle of transsubjectivity... that, beginning with my subjectivity, I put my actual ego up for consideration as well as heighten and transcend it by seeking to participate in a general human potential, which is only attainable by recognizing the subjectivity of the Other”, and thus as having a quasi-religious meaning.

Freeman’s syntactic criterion for linked argument structure is often readily applicable, captures intuitively linked structures, and implies that refuting a single premiss of a linked argument suffices to refute the argument. But one cannot sharply separate analysis from inference evaluation in applying it, whether an argument satisfies it can be uncertain, it under-generates cases where refuting one premiss suffices to refute an argument, some arguments satisfying it can be easily rescued if a single premiss is refuted, and Freeman’s underlying account (...) of probative relevance is dubious. (shrink)

Critical thinking arrives at a judgment on a question by looking back in a reasonable way at the relevant evidence; it is “reasonable reflective thinking focused on deciding what to believe or do” (Ennis). Its key component skills are those of clarifying meaning, analyzing arguments, evaluating evidence, judging whether a conclusion follows, and drawing warranted conclusions. An ideal “critical thinker” is open-minded and fair-minded, searches for evidence, tries to be well-informed, is attentive to others’ views and their reasons, proportions belief (...) to the evidence, and is willing to consider alternatives and revise beliefs. The process of thinking critically involves problem identification and analysis, clarification of meaning, gathering the evidence, assessing the evidence, inferring conclusions, considering other relevant information, and making an overall judgment. Critical thinking differs from the logical appraisal of arguments in extending beyond a single argument, having a creative component, and involving critical assessment of evidence. Any educational system should aim to teach the knowledge, develop the skills, and foster the attitudes and dispositions of a critical thinker: someone who thinks critically when it is appropriate to do so, and who does so well. It can do so either by infusion in subject-matter courses or through a stand-alone course. Each method has advantages and disadvantages; a combination is theoretically better, but hard to achieve. In a stand-alone course, one should adapt to one’s situation, communicate the course goals, motivate one’s students, use a checklist as a course framework, foster a critical spirit, prefer depth to breadth, use bridging, take advantage of salient issues, use real or realistic examples, pick one’s examples with care, give students lots of guided practice with feedback, check for understanding, encourage meta-cognition, think about context, watch for empty use of technical terms, and design multiple-choice items carefully if one uses them. (shrink)

If we understand a fallacy as a mistake in reasoning that occurs with some frequency in real arguments and is characteristically deceptive, there is no argumentum ad hominem fallacy. Arguing ad hominem in its original sense is a perfectly legitimate strategy of using an interlocutor’s concessions or commitments to show that the interlocutor is committed to a certain conclusion. The tu quoque, which emerged from this sense as an appeal to commitments implicit in the behaviour of one’s critic, legitimately challenges (...) the critic to explain away an apparent inconsistency. The purely abusive ad hominem is either a legitimate attack on an opponent’s ethos or an objectionable diversionary tactic that is not a kind of reasoning. The circumstantial ad hominem, which attributes the position of one’s opponent to self-interest or a dogmatic bias, raises legitimate suspicion about the credibility of the opponent’s statements and arguments. (shrink)

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

37 arguments were selected by random sampling methods from calls to radio and television phone-in programs. I discuss whether my general theory of inference evaluation applies to them and how frequently they exemplify a recognized argument scheme. I also compare their dependence on context, their complexity and their quality to those features of a previously studied sample of 50 scholarly arguments.

In reasoning by analogy, we project a queried property from one or more source cases to a target case on the basis of one or more assumed similarities. There are three ways in which such reasoning can be inferentially sound. First, the variables of which the assumed similarities are values may determine, tightly or loosely, the variable of which the queried property is a value. Second, we may recognize that the source cases have the queried property in virtue of having (...) the assumed similarities. Thirdly, and most weakly, sources and target may share many and varied similarities and have few dissimilarities. (shrink)

One can generate argumentation schemes in three ways. A bottom-up approach of extracting patterns of argument from a corpus of actual arguments can be somewhat arbitrary, and is likely to produce an unsatisfactory guide to understanding and evaluating arguments. A top-down approach starting from taxonomies of statements and rules of inference risks a combinatorial explosion of abstract unrealized possibilities. A combined approach is more useful.

The case for including fallacies in teaching critical thinking is weaker than it seems. Further, there are at least four arguments against using fallacies as a framework for teaching critical thinking. Empirical research is needed to determine what kinds of mistakes in reasoning occur most commonly in arguments and what effect teaching the fallacies has on critical thinking dispositions and skills.

I resolve an apparently unresolved dispute about how probable uniform experience makes an extrapolation from it, and draw some general lessons about such enumerative induction. Uniform experience does not necessarily confer a high probability on an extrapolation of or generalization from that experience. Rational extrapolation or generalization typically involves a lot of specific background information, though not necessarily a general assumption that nature is uniform or that the future will resemble the past. And new evidence which is highly likely on (...) one hypothesis but highly unlikely on any of its competitors does not necessarily make the former hypothesis highly probable. (shrink)

Comprehensive reasoning from end to means requires an initiating intention to bring about some goal, along with five premisses: a specified means would immediately contribute to realization of the goal, the goal is achievable, the means is permissible, no alternative means is preferable, and the side effects do not outweigh the benefits of achieving the goal. Its conclusion is a decision to bring about the means. The scheme can be reiterated until an implementable means is reached. In a particular context, (...) resource limitations may warrant truncation of the reasoning. (shrink)

In Giving Reasons, Bermejo-Luque rightly claims that a normative model of the speech act of argumentation is more defensible if it rests on an internal aim that is constitutive of the act of arguing than if it rests, as she claims existing normative models do, on an aim that one need not pursue when one argues. She rightly identifies arguing with trying to justify something. But it is not so clear that she has correctly identified the internal aim of arguing (...) as showing that a target-claim is correct on the basis that a reason offered in its support is correct. First, if arguing is as she claims an attempt to justify, it is best construed as an attempt to justify the action or emotion expressed in its conclusion. Second, it is doubtful that qualified reasons and conclusions can always be reasonably reconstructed as unqualified claims, and even more doubtful that non-constative reasons and conclusions can always be reasonably reconstructed as indirect claims. Third, she needs to explain and justify her introduction of the concepts of showing and correctness in her analysis of the act of arguing. (shrink)

After clarifying what plato means by "the good," noting accounts of the good which he explicitly rejects in the "republic", and carefully interpreting the comparison of the good with the sun at "republic" 508-509, this paper infers from the comparison that the good is unity. It then examines the coherence of this account with what the "republic" says about the foundations of mathematics and about the good of individuals and of cities, and offers a preliminary appraisal.

In his 1933 monograph on the concept of truth, Alfred Tarski claimed that his definition of truth satisfied “the usual conditions of methodological correctness”, which in a 1935 article he identified as consistency and back-translatability. Following the rules of defining for an axiomatized theory was supposed to ensure satisfaction of the two conditions. But Tarski neither explained the two conditions nor supplied rules of defining for any axiomatized theory. We can make explicit what Tarski understood by consistency and back-translatability, with (...) the help of (1) an account by Ajdukiewicz (1936) of the criteria underlying the practice of articulating rules of defining for axiomatized theories and (2) a critique by Frege (1903) of definitions that conjure an object into existence as that which satisfies a specified condition without first proving that exactly one object does so. I show that satisfaction of the conditions of consistency and back-translatability as thus explained is guaranteed by the rules of defining articulated by Leśniewski (1931) for an axiomatized system of propositional logic. I then construct analogous rules of defining for the theory within which Tarski developed his definition of truth. Tarski’s 32 definitions in this theory occasionally violate these rules, but the violations are easily repaired. I argue that the Leśniewski-Ajdukiewicz theory of formal correctness of definitions within which Tarski worked is superior in some respects to the widely accepted analogous theory articulated by Suppes (1957). (shrink)

I apply the apparatus of my book Definition (2021) to the task of defining antisemitism. An initial stipulation introduced the word ‘Semitismus’ into the German language as a synonym for ‘Judenthum’ (‘Jewishness’). I raise two objections to this stipulation. First, the choice of term risked what Ennis calls ‘impact equivocation’, since it could easily be misunderstood as referring to characteristics common to all speakers of Semitic languages, including Arabic as well as Hebrew. Second, the stipulator’s use of either name assumed (...) falsely that all Jews share the described characteristics. I use a sample of 10 sentences to evaluate 11 proposed reportive (i.e., descriptive, or lexicographical) definitions of the term ‘antisemitism’. I rephrase the resulting tentative definition in the Natural Semantic Language developed by Goddard and Wierzbicka. I then consider two documents that advocate a meaning for ‘antisemitism’, in the sense that they take a position on what kinds of speech or action count as antisemitic. The Jerusalem Declaration on Antisemitism, issued by a group of researchers in 2021, is superior in many respects to the resolution on antisemitism adopted in May 2016 by the International Holocaust Remembrance Alliance (IHRA). Hence individuals and organizations concerned with monitoring antisemitism should use the Jerusalem Declaration as a guide rather than the IHRA resolution. Consideration of the declaration leads to a revised reportive definition: Antisemitism is discrimination, prejudice, hostility, or violence that targets people or institutions regarded as ethnically Jewish, just because they are Jewish. (shrink)

In mutual inquiry two or more people seek rational agreement on an answer to an open question. Rules for a dialogue system for mutual inquiry should conform to at least the following 18 principles: externalization, dialectification, mutuality, turn-taking, orderliness, staging, logical pluralism, rule-consistency, semantic openness, realism, retractability, role reversal, experiential appeal, openness, tentativeness, tracking, termination rules, allocation of burden of proof.