Eristic has been studied more and more intensively in recent years in philosophy, law, communication theory, logic, proof theory, and A.I. Nevertheless, the modern origins of eristic, which almost all current researchers see in the philosopher Arthur Schopenhauer, are considered to be a theory of the illegitimate use of logical and rhetorical devices. Thus, eristic seems to violate the norms of discourse ethics. In this paper, I argue that this interpretation of eristic is based on prejudices that contradict the original (...) intention of modern eristic. Eristic is not an art of being right or winning an argument, but an art of protecting oneself from the one who deliberately violates norms of discourse ethics to gain argumentative acceptance. For this reason, eristic must be seen as a discipline of Enlightenment philosophy and a correlate of discourse ethics. Especially in the age of alternative facts and post-factual politics, this makes eristic a valuable discipline. (shrink)

The interpretation and the indirect reporting of a speaker’s communicative intentions lie at the crossroad between pragmatics, argumentation theory, and forensic linguistics. Since the leading case Masson v. New Yorker Magazine, Inc., in the United States the legal problem of determining the truth of a quotation is essentially equated with the correctness of its indirect reporting, i.e. the representation of the speaker’s intentions. For this reason, indirect reports are treated as interpretations of what the speaker intends to communicate. Theoretical considerations, (...) aimed at establishing the pragmatic meaning of an utterance and differentiating between presumptive and non-presumptive interpretation, are thus interwoven with the practical legal need of distinguishing a correct indirect report from an indirect one or a misquotation. An incorrect report or a misquotation has the dialectical effect of attributing to the misquoted party commitments that he never held, which the latter needs to rebut. This shifting of the burden of persuasion can be increased by using strategically the conflict between the presumptive interpretation of an utterance and the non-presumptive one, i.e. the different types of pragmatic ambiguity. When an interpreter is confronted with an utterance taken out of its dialogical context, his interpretative process is not guided by the actual context or intention, but rather the most frequent or prototypical dialogical setting or the most typical individual purpose that it could have served to achieve. This presumptive reconstruction can be used to provide a prima facie case that the other party needs to reject. The stronger the interpretative presumptions a speaker needs to rebut, the more effective the misquotation strategy. The conflict between the systematic and the presumptive process of interpretation can be represented as an argumentative mechanism of reconstruction of the individual intention, which allows one to assess the reasonableness of the interpretative reasoning. (shrink)

In this paper, we use concepts, structure and tools from argumentation theory to show how conversational implicatures are triggered by conflicts of presumptions. Presumptive implicatures are shown to be based on defeasible forms of inference used in conditions of lack of knowledge, including analogical reasoning, inference to the best explanation, practical reasoning, appeal to pity, and argument from cause. Such inferences are modelled as communicative strategies to knowledge gaps that shift the burden of providing the missing contrary evidence to the (...) other party in a dialogue. Through a series of illustrative examples, we show how such principles of inference are based on common knowledge about the ordinary course of events shared by participants in a structured dialogue setting in which they take turns putting forward and responding to speech acts. (shrink)

J. Anthony Blair is a prominent international figure in argumentation studies. He is among the originators of informal logic, an author of textbooks on the informal logic approach to argument analysis and evaluation and on critical thinking, and a founder and editor of the journal Informal Logic. Blair is widely recognized among the leaders in the field for contributing formative ideas to the argumentation literature of the last few decades. This selection of key works provides insights into the history of (...) the field of argumentation theory and various related disciplines. It illuminates the central debates and presents core ideas in four main areas: Critical Thinking, Informal Logic, Argument Theory and Logic, Dialectic and Rhetoric. (shrink)

Not every speech act can be a lie. A good definition of lying should be able to draw the right distinctions between speech acts that can be lies and speech acts that under no circumstances are lies. This paper shows that no extant account of lying is able to draw the required distinctions. It argues that a definition of lying based on the notion of ‘assertoric commitment’ can succeed where other accounts have failed. Assertoric commitment is analysed in terms of (...) two normative components: ‘accountability’ and ‘discursive responsibility’. The resulting definition of lying draws all the desired distinctions, providing an intensionally adequate analysis of the concept of lying. (shrink)

The informal logic movement began as an attempt to develop – and teach – an alternative logic which can account for the real life arguing that surrounds us in our daily lives – in newspapers and the popular media, political and social commentary, advertising, and interpersonal exchange. The movement was rooted in research and discussion in Canada and especially at the University of Windsor, and has become a branch of argumentation theory which intersects with related traditions and approaches (notably formal (...) logic, rhetoric and dialectics in the form of pragma-dialectics). In this volume, some of the best known contributors to the movement discuss their views and the reasoning and argument which is informal logic’s subject matter. Many themes and issues are explored in a way that will fuel the continued evolution of the field. Federico Puppo adds an insightful essay which considers the origins and development of informal logic and whether informal logicians are properly described as a “school” of thought. In considering that proposition, Puppo introduces readers to a diverse range of essays, some of them previously published, others written specifically for this volume. (shrink)

The article develops and justifies, on the basis of the epistemological argumentation theory, two central pieces of the theory of evaluative argumentation interpretation: 1. criteria for recognizing argument types and 2. rules for adding reasons to create ideal arguments. Ad 1: The criteria for identifying argument types are a selection of essential elements from the definitions of the respective argument types. Ad 2: After presenting the general principles for adding reasons (benevolence, authenticity, immanence, optimization), heuristics are proposed for finding missing (...) reasons, for deductive arguments, e.g., semantic tableaux are suggested. (shrink)

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

This paper aims to contribute to an understanding of the politicians’ burden of proof in political interviews by explaining how politicians attempt to delimit the burden of proof which they acquire for their standpoints in response to criticism. As politicians always want to give a positive evaluation of their activities, they respond to the critics by delimiting their burden of proof in such a way that their standpoints are easy to defend. The research question to be answered is: How do (...) politicians expediently delimit their burden of proof in political interviews in response to criticism? First, the author characterizes political interviews as accountability practices which by virtue of their institutional traits impose limits on the politicians’ burden of proof. Second, the author explains some of the possibilities for delimiting the burden of proof in the communicative practices at issue by analyzing in detail several fragments from a political interview. (shrink)

This paper revisits the challenge of Berman and Hafner’s “missing link” paper on representing teleological structure in case-based legal reasoning. It is noted that this was mainly an ontological challenge to represent some of what made legal reasoning distinctive, which was given less attention than factual similarity in the dominant AI and Law paradigm, deriving from HYPO. The response to their paper is noted and briefly evaluated. A parallel is drawn to a new challenge to provide deep structure to the (...) legal context of textual meaning, drawing on the forthcoming work of two Constitutional law scholars who appear to place some faith in the ways of thinking that AI and Law has developed. (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)

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)

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)

Some critical reactions hardly give clues to the arguer as to how to respond to them convincingly. 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 (...) there are normative requirements that enhance the directiveness of criticism. Does the opponent have in circumstances a dialectical obligation to provide clarifications, explanations, or even arguments? In this paper, it is hypothesized that the competitiveness 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 argumentative strategy that defuses them. (shrink)

Standards and norms for reasoning function, in part, to manage epistemic risk. Properly used, modal qualifiers like presumably have a role in systematically managing epistemic risk by flagging and tracking type-specific epistemic merits and risks of the claims they modify. Yet, argumentation-theoretic accounts of presumption often define it in terms of modalities of other kinds, thereby failing to recognize the unique risk profile of each. This paper offers a stipulative account of presumption, inspired by Ullmann-Margalit, as an inferentially generated modal (...) qualifier, “presumably, p,” distinguishing it from other, particularly epistemic modalities, e.g., standing commitments, assumptions, assertions, suppositions, hypotheses, and defeasible claims. By avoiding the tranching of inferential instruments of qualitatively different bona fides and risk profiles, this account provides a more accurate risk-rating system that better manages epistemic risk in inference, as well as contributing to the normative theory of the operation of presumption in reasoning and argument. (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)

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)

Dying is easy; comedy is hard. Comedy is sovereign. I begin with an excerpt from Bertolt Brecht’s Fugitive Conversations. Ziffel, a physicist, is chatting with the worker Kalle: For humor, I always think of the philosopher Hegel.... He had the makings of one of the greatest humorists among the philosophers.... I read his book The Great Logic once, when I had rheumatism and couldn’t move. It’s one of the greatest humorous works of world literature. It treats of the way of (...) life of concepts, those slippery, unstable, irresponsible existences; how they abuse one another and fight with knives and then sit down together to supper as though nothing had happened.... They can live... (shrink)

I argue for the distinction between presuming that p and maintaining that presumably p. In order to make sense of this distinction, I defend a non-inferentialist conception of presumptions and offer an account of the correctness conditions for both presumptions and presumptive inferences. I characterize presumptions as a type of constative speech-act having certain semantic correctness conditions. In turn, regarding presumptive inferences, my strategy is to provide the correctness conditions for the use of an epistemic modal such as “presumably.” This (...) epistemic modal is characterized as a force indicator for speech-acts of concluding in complex speech-acts of arguing involving presumptive inferences. (shrink)

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

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.

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.

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)

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.

Metaphorical meaning can be analyzed as triggered by an apparent communicative breach, an incongruity that leads to a default of the presumptive interpretation of a vehicle. This breach can be solved through contextual renegotiations of meaning guided by the communicative intention, or rather the presumed purpose of the metaphorical utterance. This paper addresses the problem of analyzing the complex process of reasoning underlying the reconstruction of metaphorical meaning. This process will be described as a type of abductive argument, aimed at (...) explaining how the vehicle can best contribute to the purpose of the utterance. This type of reasoning involves the analysis of the possible predicates that can be and usually are attributed to the vehicle, and the selection of the one that can support the implicit conclusion constituting the communicative goal of the metaphorical utterance. Metaphorical meaning, in this perspective, becomes the outcome of a complex process of meaning reconstruction aimed at providing the best explanation of the function of the vehicle within a discourse move. (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)

semantic minimalism and moderte contextualism.

I propose a characterization of the dialectical dimension of argumentation by considering the activity of arguing as involving a “second order intersubjectivity”. I argue that argumentative communication enables this kind of intersubjectivity as a matter of the recursive nature of acts of arguing—both as justificatory and as persuasive devices. Calling attention to this feature is a way to underline that argumentative discourses represent the explicit part of a dynamic activity, “a mechanism of rational validation”, as Rescher showed, which is a (...) practice that presupposes the possibility of attaining objectivity. (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)

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)

In this overview article, we first explain what we take informal logic to be, discussing misconceptions and distinguishing our conception of it from competing ones; second, we briefly catalogue recent informal logic research, under 14 headings; third, we suggest four broad areas of problems and questions for future research; fourth, we describe current scholarly resources for informal logic; fifth, we discuss three implications of informal logic for philosophy in particular, and take note ofpractical consequences of a more general sort.

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)

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

Few, if any, scientific inquiries are conducted against a background of complete knowledge, a background in which inquirers are in possession of the ‘full facts’ that relate to a particular question or issue. More often than not, scientists are compelled to conduct their deliberations in contexts of epistemic uncertainty, in which partial knowledge or even a total absence of knowledge characterise inquiry. Nowhere is this epistemic uncertainty more evident, or indeed more successfully controlled, than in the branch of scientific inquiry (...) called epidemiology. In this paper, I examine how epidemiologists overcome the unique challenges to inquiry that are posed by epistemic uncertainty. In specific terms, I contend that epidemiologists employ analogical reasoning strategies in an attempt to advance their inquiries in situations that are epistemically uncertain. The context for my claims will be the early inquiries that were conducted into the emergence of HIV/AIDS in the United States. I argue that early scientific work in relation to HIV/AIDS was directly premised upon epidemiological investigations in which analogical reasoning with hepatitis B had featured significantly. I conclude that epidemiological investigations of AIDS exemplify the capacity of analogical reasoning to advance inquiry under conditions of epistemic uncertainty. To this extent, analogical reasoning should be a concern both to those who address practical problems of uncertainty management and to those who pursue theoretical debates within argumenta-tion studies and epistemology. (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)

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 applicability of Bayesian conditionalization in setting one’s posterior probability for a proposition, α, is limited to cases where the value of a corresponding prior probability, PPRI(α|∧E), is available, where ∧E represents one’s complete body of evidence. In order to extend probability updating to cases where the prior probabilities needed for Bayesian conditionalization are unavailable, I introduce an inference schema, defeasible conditionalization, which allows one to update one’s personal probability in a proposition by conditioning on a proposition that represents a (...) proper subset of one’s complete body of evidence. While defeasible conditionalization has wider applicability than standard Bayesian conditionalization (since it may be used when the value of a relevant prior probability, PPRI(α|∧E), is unavailable), there are circumstances under which some instances of defeasible conditionalization are unreasonable. To address this difficulty, I outline the conditions under which instances of defeasible conditionalization are defeated. To conclude the article, I suggest that the prescriptions of direct inference and statistical induction can be encoded within the proposed system of probability updating, by the selection of intuitively reasonable prior probabilities. (shrink)

In this work it is argued that legal justification can best be studied from a procedural, dialogical point of view: legal statements are justified if the audience is convinced in an argumentative dialog. The formalized and implemented model DiaLaw guards the procedure in which two players aim at justifying statements. DiaLaw shows the advances and problems linked to procedural models of legal justification. Moreover, an instructive discussion of the different models of procedural justification is provided. It is stressed that in (...) legal justification not only logically compelling arguments should be considered, but also convincing arguments. Therefore DiaLaw also deals with the rhetorical, psychological aspects of argument. This book is relevant for scholars in legal theory, artificial intelligence, and argumentation, and can be used in graduate courses on AI and Law, and legal argumentation. (shrink)

A general outline of a theory of reasoned dialogue is presented as an underlying basis of critical analysis of a text of argument discourse. This theory is applied to the analysis of informal fallacies by showing how textual evidence can be brought to bear in argument reconstruction. Several basic types of dialogue are identified and described, but the persuasive type of dialogue is emphasized as being of key importance to critical thinking theory.

We provide a retrospective of 25 years of the International Conference on AI and Law, which was first held in 1987. Fifty papers have been selected from the thirteen conferences and each of them is described in a short subsection individually written by one of the 24 authors. These subsections attempt to place the paper discussed in the context of the development of AI and Law, while often offering some personal reactions and reflections. As a whole, the subsections build into (...) a history of the last quarter century of the field, and provide some insights into where it has come from, where it is now, and where it might go. (shrink)

How is the burden of proof to be distributed among individuals who are involved in resolving a particular issue? Under what conditions should the burden of proof be distributed unevenly? We distinguish attitudinal from dialectical burdens and argue that these questions should be answered differently, depending on which is in play. One has an attitudinal burden with respect to some proposition when one is required to possess sufficient evidence for it. One has a dialectical burden with respect to some proposition (...) when one is required to provide supporting arguments for it as part of a deliberative process. We show that the attitudinal burden with respect to certain propositions is unevenly distributed in some deliberative contexts, but in all of these contexts, establishing the degree of support for the proposition is merely a means to some other deliberative end, such as action guidance, or persuasion. By contrast, uneven distributions of the dialectical burden regularly further the aims of deliberation, even in contexts where the quest for truth is the sole deliberative aim, rather than merely a means to some different deliberative end. We argue that our distinction between these two burdens resolves puzzles about unevenness that have been raised in the literature. (shrink)

Presupposition has been described in the literature as closely related to the listener’s knowledge and the speaker’s beliefs regarding the other’s mind. However, how is it possible to know or believe our interlocutor’s knowledge? The purpose of this paper is to find an answer to this question by showing the relationship between reasoning, presumption and language. Presupposition is analyzed as twofold reasoning process: on the one hand, the speaker by presupposing a proposition presumes that his interlocutor knows it; on the (...) other hand, the listener reconstructs the propositions taken for granted and assesses them against the shared presumptions. The possibility of reconstructing a presupposition is distinguished from its assessment, where the consistency of the presupposition with the shared or common ground is evaluated, and its reasonableness established. The analysis of presuppositions from an argumentative perspective provides an instrument for evaluating the reasonableness of a presupposition and understanding its dialogical effect. On this view, the dialogical force of a presupposition lies in its presumptive nature, which sets and shifts the burden of proving its unacceptability or unreasonableness. (shrink)

In this paper a theoretical definition that helps to explain how the logical structure of legal presumptions is constructed by applying the Carneades model of argumentation developed in artificial intelligence. Using this model, it is shown how presumptions work as devices used in evidentiary reasoning in law in the event of a lack of evidence to assist a chain of reasoning to move forward to prove or disprove a claim. It is shown how presumptions work as practical devices that may (...) be useful in cases in which there is insufficient evidence to prove the claim to an appropriate standard of proof. (shrink)

An approach to argument macrostructure -- The dialectical nature of argument -- Toulmin's problematic notion of warrant -- The linked-convergent distinction, a first approximation -- Argument structure and disciplinary perspective : the linked-convergent versus multiple-co-ordinatively compound distinctions -- The linked-convergent distinction, refining the criterion -- Argument structure and enthymemes -- From analysis to evaluation.

This paper shows how reasoning from best explanation combines with linguistic and factual presumptions during the process of retrieving a speaker’s intention. It is shown how differences between presumptions need to be used to pick the best explanation of a pragmatic manifestation of a dialogical intention. It is shown why we cannot simply jump to an interpretative conclusion based on what we presume to be the most common purpose of a speech act, and why, in cases of indirect speech acts, (...) we need to depend on an abductive process of interpretation. (shrink)

This paper attempts to systematically characterize critical reactions in argumentative discourse, such as objections, critical questions, rebuttals, refutations, counterarguments, and fallacy charges, in order to contribute to the dialogical approach to argumentation. We shall make use of four parameters to characterize distinct types of critical reaction. First, a critical reaction has a focus, for example on the standpoint, or on another part of an argument. Second, critical reactions appeal to some kind of norm, argumentative or other. Third, they each have (...) a particular illocutionary force, which may include that of giving strategic advice to the other. Fourth, a critical reaction occurs at a particular level of dialogue (the ground level or some meta-level). The concepts here developed shall be applied to discussions of critical reactions by Aristotle and by some contemporary authors. (shrink)