Implicatures are described as particular forms reasoning from best explanation, in which the para-digm of possible explanations consists of the possible semantic interpretations of a sentence or a word. The need for explanation will be shown to be triggered by conflicts between presumptions, namely hearer’s dialogical expectations and the presumptive sentence meaning. What counts as the best explanation can be established on the grounds of hierarchies of presumptions, dependent on dialogue types and interlocutors’ culture.

This is the introduction to the Routledge Companion to Thought Experiments.

This volume focuses on dialogue and argumentation in contexts which are marked by truculence and discord. The contributors include well known argumentation scholars who discuss the issues this raises from the point of view of a variety of disciplines and points of view. The authors seek to address theoretically challenging issues in a way that is relevant to both the theory and the practice of argument. The collection brings together selected essays from the 2006 11th Wake Forest University Biennial Argumentation (...) Conference held at Florida Atlantic University in Boca Raton, Florida and the 2012 14th Wake Forest University Biennial Argumentation Conference held at Casa Artom in Venice, Italy. (shrink)

The ArgumentThe purpose of this article is twofold. Firstly, I propose to analyze controversies using a “dialectical” model, in the sense described in Aristotle'sTopics. This approach presupposes that we temporarily disregard, for the sake of clarity, the concreteness of real life controversies in order to focus on their argumentative structure. From this point of view, the main advantage of controversies is that they allow the interlocutorsto testeach other's claims and therefore to arrive at relatively corroborated conclusions. This testing function in (...) a dialectical context is implemented through theassentto commonly accepted premises, and thenecessitywhich characterizes each step of the reasoning.Secondly, I shall apply this dialectical framework to the study of the controversy concerning the motion of the Earth, or rather a small episode of it. I shall examine an exchange of letters, written in 1616 and in 1624 respectively, between Galileo Galilei and Francesco Ingoli, one of his Aristotelian opponents. I shall then compare this exchange with the first day of Galileo'sDialogue Concerning the Two Chief Systems of the World, a fictional debate, where Galileo discusses some of the same arguments. While the first exemplifies what I call “negative” testing, and yields a refutation of the opponent's theses, the second exemplifies “positive” testing and yields a dialectical demonstration of the motion of the Earth. (shrink)

Although debate is a richly structured and prevalent form of discourse, it has received little scholarly attention. Logicians have focused on the structure of individual arguments—how they divide into premises and conclusions, which in turn divide into various constituents. In contrast, I focus on the structure of sets of arguments, showing how arguments are themselves constituents in high-level dialectical structures. I represent debates and positions by graphs whose vertices correspond to arguments and whose edges correspond to two inter-argument relations: “dispute” (...) and “support,” respectively. On this basis I develop a theory of the structure of debate. (shrink)

If one looks to the current textbook lore for reliable taxonomic and analytical information about the petitio principii, one is met with conceptual disarray and much too much nonsense. The present writers have recently attempted to furnish the beginnings of a theoretical reconstruction of this fallacy which is at once faithful to its formidable complexity yet useful as guide for its detection and avoidance. The fact is that the petitio has had a lengthy and interesting history, and in this paper (...) we shall want to explore certain features of its development, such as it may have been. The principal origins of the concept of circular argument are to be found in Aristotle. The Aristotelian doctrine recurs with variations in the sophismata literature of the middle ages and in logic texts and manuals right up to the present day. (shrink)

If one looks to the current textbook lore for reliable taxonomic and analytical information about the petitio principii, one is met with conceptual disarray and much too much nonsense. The present writers have recently attempted to furnish the beginnings of a theoretical reconstruction of this fallacy which is at once faithful to its formidable complexity yet useful as guide for its detection and avoidance. The fact is that the petitio has had a lengthy and interesting history, and in this paper (...) we shall want to explore certain features of its development, such as it may have been. The principal origins of the concept of circular argument are to be found in Aristotle. The Aristotelian doctrine recurs with variations in the sophismata literature of the middle ages and in logic texts and manuals right up to the present day. (shrink)

In this paper a dialogue game for critical discussion is developed. The dialogue game is a formalisation of the ideal discussion model that is central to the pragma-dialectical theory of argumentation. The formalisation is intended as a preparatory step to facilitate the development of computational tools to support the pragma-dialectical study of argumentation. An important dimension of the pragma-dialectical discussion model is the role played by speech acts. The central issue addressed in this paper is how the speech act perspective (...) can be accommodated in the formalisation as a dialogue game. The starting point is an existing ‘basic’ dialogue game for critical discussion, in which speech acts are not addressed. The speech act perspective is introduced into the dialogue game by changing the rules that govern the moves that can be made and the commitments that these result in, while the rules for the beginning, for the end, and for the structure of the dialogue game remain unchanged. The revision of the move rules is based on the distribution of speech acts in the pragma-dialectical discussion model. The revision of the commitment rules is based on the felicity conditions that are associated with those speech acts. (shrink)

Some critical reactions hardly give clues to the arguer as to how to respond to them convinc-ingly. Other critical reactions convey some or even all of the considerations that make the critic critical of the arguer’s position and direct the arguer to defuse or to at least contend with them. First, an explication of the notion of a critical reaction will be provided, zooming in on the degree of ‘directiveness’ that a critical reaction displays. Second, it will be examined whether (...) and to what extent there is a normative requirement to strive after criticism that is more than minimally directive. In this paper, it is hypothesized that the com-petitiveness inherent in critical discussion must be mitigated by making the opponent responsible for providing her counterconsiderations, if available, thus assisting the proponent in developing an argumenta-tive strategy that defuses them. (shrink)

It furthers the dialectic when the opponent is clear about what motivates and underlies her critical stance, even if she does not adopt an opposite standpoint, but merely doubts the proponent’s opinion. Thus, there is some kind of burden of criticism. In some situations, there should an obligation for the opponent to offer explanatory counterconsiderations, if requested, whereas in others, there is no real dialectical obligation, but a mere responsibility for the opponent to cooperate by providing her motivations for being (...) critical. In this paper, it will be shown how a set of dialogue rules may encourage an opponent, in this latter type of situation, to provide her counterconsiderations, and to do so at an appropriate level of specificity. Special attention will be paid to the desired level of specificity. For example, the critic may challenge a thesis by saying “Why? Says who?,” without conveying whether she could be convinced by an argument from expert opinion, or from position to know, or from popular opinion. What are fair dialogue rules for dealing with less than fully specific criticism? (shrink)

This work discusses an empirical study of reasoning as it occurs in conversations. Reasoning in this context has features not usually accounted for in standard methods for describing argumentation (e.g., Toulmin, (1964), Toulmin, Rieke, and Janik (1984)). For example, insufficient attention has been paid to challenges which can be used to shift the ground of an argument and to the development of multiple conversational grounds. Moreover, even though the value of cooperative efforts in building arguments is widely recognized, more needs (...) to be said about analyzing co-constructed arguments. This empirical work was primarily descriptive and concerned with how people construct arguments in conversations, but one goal of the study was to lay groundwork for comparing the quality of reasoning in conversations which differ with respect to whether the arguments they contain are primarily the contributions of individuals or are genuinely co-constructed arguments. (shrink)

Argumentation involves offering and/or exchanging reasons – either reasons for adopting various attitudes towards specific propositional contents or else reasons for acting in various ways. This paper develops the idea that the force of reasons is through and through a normative force because what good reasons accomplish is precisely to give one a certain sort of entitlement to do what they are reasons for. The paper attempts to shed light on what it is to have a reason, how the sort (...) of entitlement arising from reasons differs from other species of entitlement and how the norms by which such entitlement is assessed obtain their status as norms. (shrink)

When we use a word, we face a crucial epistemic gap: we ground our move on the fact that our interlocutor knows the meaning of the word we used, and therefore he can interpret our dialogical intention. However, how is it possible to know the other’s mind? Hamblin explained this dialogical problem advancing the idea of dialectical meaning: on his view, the use of a word is based on a set of presumptions. Building on this approach, the use of a (...) word in a dialogue can be analyzed in terms of presumptive reasoning, while the manipulative strategies based on slanted or loaded terms or redefinitions can be conceived as forms of conflicts of presumptions. A presumptive approach to meaning can also ground different dialectical strategies to solve misunderstanding or definitional disagreements, or tactics to undermine the interlocutor’s arguments by advancing charges of equivocation. (shrink)

The implicit dimension of enthymemes is investigated from a pragmatic perspective to show why a premise can be left unexpressed, and how it can be used strategically. The relationship between the implicit act of taking for granted and the pattern of presumptive reasoning is shown to be the cornerstone of kairos and the fallacy of straw man. By taking a proposition for granted, the speaker shifts the burden of proving its un-acceptability onto the hearer. The resemblance of the tacit premise (...) with what is commonly acceptable or has been actually stated can be used as a rhetorical strategy. (shrink)

In his theory of criticism, D. N. Walton presupposes that an opponent either critically questions an argument, without supplementing this questioning with any reasoning of her own, or that she puts forward a critical question and supplements it with a counterargument, that is, with reasoning in defense of an opposite position of her own. In this paper, I show that there is a kind of in-between critical option for the opponent that needs to be taken into account in any classification (...) of types of criticism, and that should not be overlooked in a system of dialogue norms, nor in a procedure for developing a strategically expedient critique. In this third option, an opponent questions and overtly doubts a statement of the proponent and supplements her doubts with a counterconsideration that explains and motivates her position of critical doubt, yet without supporting any opposite thesis, thereby assisting, as it were, the proponent in his attempt to develop a responsive argumentation, tailor-made to convince this particular opponent. First, I elaborate on the notion of an explanatory counterconsideration. Second, I discuss Walton’s distinction between premises that can be challenged by mere questioning and premises that must be challenged by incurring the obligation to offer counter-argumentation. I contend that the latter type of premises, that I would label “normality premises,” can be attacked without incurring a genuine burden of proof. Instead, it can be attacked by means of incurring a burden of criticism that amounts to the obligation to offer an explanatory counterconsideration, rather than a convincing ex concessis argument. Of course, providing the opponent with the right to discharge her burden of criticism with explanatory counterconsiderations brings a clear strategic ad- vantage to her. It is much less demanding to motivate one’s doubts regarding proposition P, than to convince the proponent of not-P. If we want to encourage opponents to act critically, and proponents to develop responsive arguments, the importance of the notions of an explanatory counterconsideration and of a motivated doubt should be emphasized in the theory of criticism. (shrink)

Arguments from analogy are pervasive in everyday reasoning, mathematics, philosophy, and science. Informal logic studies everyday argumentation in ordinary language. A branch of fuzzy logic, approximate reasoning, seeks to model facets of everyday reasoning with vague concepts in ill-defined situations. Ways of combining the results from these fields will be suggested by introducing a new argumentation scheme—a fuzzy analogical argument from classification—with the associated critical questions. This will be motivated by a case study of analogical reasoning in the virtual friendship (...) debate within information ethics. The virtual friendship debate is a disagreement over whether virtual friendships are genuine friendships. It will be argued that the debate could move away from its current impasse, caused by unproductive metaphysical and logical assumptions, if extant arguments are reinterpreted as fuzzy analogical arguments from classification, and subjected to a new set of critical questions which would replace the quest for facts of essence about friendship with an emphasis on empirical data, persuasion, and definitional power. (shrink)

This essay presents a dialogical framework for treating philosophical disagreements as persuasion dialogues with analogical argumentation, with the aim of recasting philosophical disputes as disagreements over analogies. This has two benefits: it allows us to temporarily bypass conflicting metaphysical intuitions by focusing on paradigmatic examples, similarities, and the plausibility of conclusions for or against a given point of view; and it can reveal new avenues of argumentation regarding a given issue. This approach to philosophical disagreements is illustrated by studying the (...) role of argumentation by analogy in disputes over Lockean justifications of intellectual property rights, and disagreements over whether artificial agents should be treated as moral agents. Finally, a nonexhaustive list of possible global and local points of contention over analogical arguments is identified in order to highlight potential avenues of argumentation in disagreements over analogies. (shrink)

In this paper I investigate the similarities betweenthe dialectical procedure in the pragma-dialecticaltheory and dialectical procedures in AI and Law. I dothis by focusing on one specific type of reasoning inlaw: analogy argumentation. I will argue that analogyargumentation is not only a heuristic forfinding new premises, but also a part of thejustification of legal decisions. The relevantcriteria for the evaluation of analogy argumentationare not to be found at the logical level of inference,but at the procedural level of the discussion. I (...) willproceed as follows. I start with an outline ofPrakken's theory of argumentation frameworks andprocedural models. Then, I will discuss Peczenik'sanalysis of analogy argumentation and try to combineit with the descriptive-normative research ofMacCormick and Summers. Finally, I propose asystematization of the criteria for the evaluation ofanalogy argumentation within the framework of apragma-dialectical notion of an argumentation scheme. (shrink)

This paper is an exercise in intellectual history, an attempt to understand how a specific term—”informal logic”— came to be interpreted in so many different ways. I trace the emergence and development of “informal logic” to help explain the many different meanings, how they emerged and how they are related. This paper is also, to some degree, an account of a movement that developed outside the mainstream of philosophy, whose origins lie in a desire to make logic useful (echoing Dewey).

The appeal to expert opinion is an argument form that uses the verdict of an expert to support a position or hypothesis. A previous scheme-based treatment of the argument form is formalized within a Bayesian network that is able to capture the critical aspects of the argument form, including the central considerations of the expert's expertise and trustworthiness. We propose this as an appropriate normative framework for the argument form, enabling the development and testing of quantitative predictions as to how (...) people evaluate this argument, suggesting that such an approach might be beneficial to argumentation research generally. We subsequently present two experiments as an example of the potential for future research in this vein, demonstrating that participants' quantitative ratings of the convincingness of a proposition that has been supported with an appeal to expert opinion were broadly consistent with the predictions of the Bayesian model. (shrink)

A generation before Beardsley, legal scholar John Henry Wigmore invented a scheme for representing arguments in a tree diagram, aimed to help advocates analyze the proof of facts at trial. In this essay, I describe Wigmore's "Chart Method" and trace its origin and influence. Wigmore, I argue, contributes to contemporary theory in two ways. His rhetorical approach to diagramming provides a novel perspective on problems about the theory of reasoning, premise adequacy, and dialectical obligations. Further, he advances a novel solution (...) to the problem of assessing argument quality by representing the strength of argument in meeting objections. (shrink)

Harry Collins' central argument about experimental practice revolves around the thesis that facts can only be generated by good instruments but good instruments can only be recognized as such if they produce facts. This is what Collins calls the experimenters' regress. For Collins, scientific controversies cannot be closed by the ‘facts’ themselves because there are no formal criteria independent of the outcome of the experiment that scientists can apply to decide whether an experimental apparatus works properly or not.No one seems (...) to have noticed that the debate is in fact a rehearsal of the ancient philosophical debate about skepticism. The present article suggests that the way out of radical skepticism offered by the so-called mitigated skeptics is a solution to the problem of consensus formation in science.Keywords: Argumentation; Skepticism; Sociology of science; Philosophy of science; Scientific controversies. (shrink)

Lilian Bermejo-Luque has posed these questions:1.What is the relationship between presumption and presumptive inference? 2.What are the correctness conditions for presumptions and presumptive inferences? Cohen’s method of relevant variables, Toulmin’s model, and Rescher’s theory of plausibility suggest answers. An inference is presumptive just in case its warrant transfers presumption from its premises to its conclusion. A warrant licencing an inference from the claim that an empirical property φ holds to the claim that some other property ψ holds is backed by (...) observation of a constant conjunction of those properties. The stronger the backing, the stronger the warrant. Warrants may be defeated by instances of φ holding in conjunction with some property χ and ψ not holding. The method of relevant variables directs us to organize such defeating properties into relevant variables. We then test the strength of a warrant by seeing how many variables fail to have a value which defeats the warrant. The more variables with no defeater, the stronger the warrant. We may construct a canonical ordering of the relevant variables by ranking them according to the plausibility of their including defeating values. We may evaluate the strength not only of empirically backed warrants, but warrants backed by institutional rules, such as a branch of law, or by a priori intuited connections between properties. An inference rule will be presumptive just in case the plausibility of its warrant being defeated is below some specified level. (shrink)

lt is now commonplace in fallacy inquiry for many of the traditional informal fallacies to be viewed as reasonable or nonfallacious modes of argument. Central to this evaluative shift has been the attempt to examine traditional fallacies within their wider contexts of use. However, this pragmatic turn in fallacy evaluation is still in its infancy. The true potential of a contextual approach in the evaluation of the fallacies is yet to be explored. I examine how, in the context of scientific (...) inquiry, certain traditional fallacies function by conferring epistemic gains upon inquiry. Specifically, I argue that these fallacies facilitate the progression of inquiry, particularly in the initial stages ofinquiry when the epistemic context is one of uncertainty. The conception of these fallacies that emerges is that of heuristics of reasoning in contexts of epistemic uncertainty. (shrink)

By explaining the argument from ignorance in terms of the presumption of innocence, many textbooks in argumentation theory suggest that some arguments from ignorance might share essential features with some types of presumptive reasoning. The stronger version of this view, suggesting that arguments from ignorance and presumptive reasoning are almost indistinguishable, is occasionally proposed by Douglas Walton. This paper explores the nature and limits of the stronger proposal and argues that initial presumptions and arguments from ignorance are not closely connected. (...) There are three main reasons. First, the argument from ignorance, unlike typical presumptive reasoning, is a negative kind of inference. Second, the typical initial presumption is sensitive to a broader set of defeaters and thus assumes a higher standard of acceptability. Third, in dialectical terms, initial presumption and argument from ignorance bring different attacking rights and obligations. I conclude that Waltonian intuition is unsupported or, at best, is limited only to practical presumptions and practical arguments from ignorance. (shrink)

In this paper, the author examines the burden of proof in the argu- mentative confrontations taking part in practices of political accountability. She does so by explaining how politicians maneuver strategically with the burden of proof in an attempt at winning the discussion in which they are involved. After making clear the role of the burden of proof in defining the difference of opinion in argumentative confrontations, the author outlines the constraints imposed by practices of political accountability on the burden (...) of proof. Finally, she analyzes in detail a concrete case in which a politician maneuvers in such a way that his burden of proof is significantly diminished. (shrink)

Are there any logical norms for argument evaluation besides soundness and inductive strength? The paper will look at several concepts or models introduced over the years, including those of Wisdom, Toulmin, Wellman, Rescher, defeasible reasoning proponents and Walton to consider whether there is common ground among them that supplies an alternative to deductive validity and inductive strength.

David Hitchcock, in his recent “Informal Logic and the Concept of Argument”, defends a recursive definition of ‘argument.’ I present and discuss several problems that arise for his definition. I argue that refining Hitchcock’s definition in order to resolve these problems reveals a crucial, but minimally explicated, relation that was, at best, playing an obscured role in the original definition or, at worst, completely absent from the original definition.

Why is there so much distortion in ordinary, political, social, and ethical argument? Since we have a pervasive interest in reasoning well and corresponding abilities, the extent of distortion invites explanation. The leading candidates are the need to economize, widespread, fallacious heuristics or assumptions, and self-defensive biases. I argue that these are not sufficient. An additional force is the intellectual pressure generated by acceptance of norms of conversation and argument, which exclude ‘middles’ of, prominently, neither accept nor reject. I conjecture (...) that the distortion we find is due to intellectual and normative pressures generated by our commitment to these excluded-middle norms and if, or when, their force is lessened, there is likely to be less distortion. (shrink)

The involvement of social considerations in our ordinary conception of presumption and corresponding plain practice of presuming things raises doubts as to whether they afford epistemically satisfying bases for rational argumentation. To some this involvement illuminates important modes of discursive inquiry; to others it points to the need for theoretically based reform or regulation of our ordinary practices. This paper attempts to clarify and defend the epistemic value of ordinary presumptions.

In argumentation, as elsewhere, speakers strategically engage favourable presumptions by manifestly making themselves accountable for their communicative efforts. Such strategies provide the addressee with reasons to regard the speaker as accountable in specific ways and, via that regard for the speaker, with situation-specific rationales for responding positively to what the speaker says. This paper identifies some resources available to arguers for strengthening, elaborating, and focusing such special presumptions. The paper offers an analysis of Barbara Jordan’s “Statement on the Articles of (...) Impeachment” as illustrative of these resources for strengthening a speaker’s ethos. (shrink)

The thesis of my paper is that argumentation theory provides a promising heuristic framework for addressing issues raised by the rationality debates in the philosophy of science, in particular the issues connected with scientific controversies over the appraisal and choice of competing theories. The first part of the paper grounds this thesis historically. In criticizing the logical empiricists, Thomas Kuhn set the stage for the subsequent opposition between a normative, anti-sociological philosophy of science and a descriptive, anti-philosophical sociology of knowledge. (...) But he also hinted at the main lines of a multi-dimensional theory of argumentation which might frame a wide range of current investigations into scientific reasoning. In the second part of the paper I focus on the central normative aspect of this framework, dialectical argumentation, and clarify the key challenge, the underdetermination of theories by evidence. In the third part, I attempt to get beyond the dichotomy informing the rationality debates by reformulating the problem of theory choice within a broader context of scientific rationality. (shrink)

In a doctor-linguist collaboration, a framework of reasoning in clinical contexts is presented. Arguments used for inquiry, justification and persuasion are sketched in diagnosis, counselling, and management settings integral to everyday clinical practice thereby extending the diagnostic function typically associated with clinical reasoning per se. A system of logic, a method of persuasive orientation, and a synthesis of negotiation in dialogue are then elaborated to illustrate the complexity of argument practice in medical culture.

Following Rescher’s conception of dialectics, I argue for the view that the dialectical aspect of argumentation enables a “second order intersubjectivity”, to be understood in terms of the recursive nature of the activity of giving and asking for reasons. This feature underlies that most argumentative discourses represent the explicit part of a dynamic activity, “a mechanism of rational validation” which presupposes the possibility of attaining objectivity.

Is truth a condition of premise adequacy? We may distinguish objective and subjective argument correctness. Objective correctness means true premises rendering the conclusion true or probable. Subjective correctness means acceptable pr emises rendering the conclusion acceptable. Acceptability depends on evidence available and so is internalist. Objective and subjective correctness of the premises is ordinarily distinct. For connection adequacy, objective rightness and subjective righ tness coincide. We recognize entailment or rendering probably a priori. Logic is thus internalist. Logic needs an internalist (...) notion of acceptability for premise evaluation to fall within its purview, although it need not deny the objective sens e of rightness. (shrink)