This paper uses argument diagrams, argumentation schemes, and some tools from formal argumentation systems developed in artificial intelligence to build a graph-theoretic model of relevance shown to be applicable as a practical method for helping a third party judge issues of relevance or irrelevance of an argument in real examples. Examples used to illustrate how the method works are drawn from disputes about relevance in natural language discourse, including a criminal trial and a parliamentary debate.

Amphiboly has been widely recognized, starting from the time of Aristotle, as an informal fallacy arising from grammatical ambiguity. This paper applies the profiles of dialogue tool to the fallacy of amphiboly, providing a five-step evidence-based procedure whereby a syntactically ambiguous sentence uttered in a natural language text can be evaluated as committing a fallacy of amphiboly. A user applies the tool to a natural language text by comparing a descriptive graph, representing how the argumentation actually went, to a normative (...) graph, representing how the argumentation should ideally have proceeded. (shrink)

The standard account of denying the antecedent (DA) is that it is a deductively invalid form of argument, and that, in a conditional argument, to argue from the falsity of the antecedent to the falsity of the consequent is always fallacious. In this paper, we argue that DA is not always a fallacious argumentative strategy. Instead, there is a legitimate usage of DA according to which it is a defeasible argument against the acceptability of a claim. The dialectical effect of (...) denying the antecedent is to shift the burden of proof back to the original proponent of a claim. We provide a model of this non-fallacious usage which is built upon pragmatic models of argumentation. (shrink)

This paper has three dimensions, historical, theoretical and social. The historical dimension is to show how the Ciceronian system of dialectical argumentation served as a precursor to computational models of argumentation schemes such as Araucaria and Carneades. The theoretical dimension is to show concretely how these argumentation schemes reveal the interdependency of rhetoric and logic, and so the interdependency of the normative with the empirical. It does this by identifying points of disagreement in a dialectical format through using argumentation schemes (...) and critical questions. The social dimension is to show how the Ciceronian dialectical viewpoint integrates with the use of computational tools that can be used to support the principle of reason-based deliberation and facilitate deliberative democracy. (shrink)

“Reasonable hostility” is a norm of communicative conduct initially developed by studying public exchanges in education governance meetings in local U.S. communities. In this paper I consider the norm’s usefulness for and applicability to a U.S. state-level public hearing about a bill to legalize civil unions. Following an explication of reasonable hostility and grounded practical theory, the approach to inquiry that guides my work, I de-scribe Hawaii’s 2009, 18-hour pub-lic hearing and analyze selected segments of it. I show that this (...) par-ticular public hearing raised de-mands for testifiers on the anti-civil union side of the argument that rea-sonable hostility does not do a good job of addressing. Development of a norm of communication conduct for this practice, as well as others, must engage with the culture and time-specific beliefs that a society holds, beliefs that will shape not only how to argue but what may be argued and what must be assumed about particular categories of persons. (shrink)

The research discussed in this paper concerns an investigation of logical dialogue games as a vehicle for enhanced human-computer communication. The need for a dialogue capability in computer systems is argued, and a prima facie case made for dialogue games, in particular Mackenzie's "DC", as a suitable dialogue model. Empirical work concerning DC is outlined, and strategies for adoption by the computer are presented. A user interface, software architecture and conceptualised example are discussed. The hope is that the paper will (...) help bring together two groups of workers-philosophers of dialogue and designers of computer systems-to the mutual benefit of each. (shrink)

The purpose of this paper is to discuss some ways in which dialectical models can be put to computational use. In particular, we consider means of facilitating human-computer debate, means of catering for a wider range of dialogue types than purely debate and means of providing dialectical support for group dialogues. We also suggest how the computational use of dialectical theories may help to illuminate research issues in the field of dialectic itself.

Both questions as abstract objects and the speech acts, here called requests, by which we ask them play an enormous role in all argumentative practices. Nonetheless, there is hardly a proper systematic treatment of questions and requests in current argumentation theories. This paper is a first attempt at providing such a systematic treatment. This is achieved by following the ideal model of a critical discussion as elaborated over the years by the Amsterdam school of pragma-dialectics. After introducing the distinction between (...) questions and requests, the paper sets forth and illustrates the norms of questioning which implicitly underlie the four stages of a critical discussion in the standard order: confrontation, opening, argumentation, and conclusion. Among other things, it is shown that crucial insights of pragma-dialectics are illuminated by the questioning perspective, in particular the distinction between single and multiple differences of opinion, the duties of the antagonist and protagonist roles, the precise character of the argumentation stage, and the different ways in which a disagreement can be resolved. (shrink)

In many contexts a retraction of commitment isfrowned upon. For instance, it is not appreciated,generally, if one withdraws a promise or denies anearlier statement. Critical discussion, too, caneasily be disrupted by retractions, if these occur toofrequently and at critical points. But on the otherhand, the very goal of critical discussion –resolution of a dispute – involves a retraction,either of doubt, or of some expressed point of view.A person who never retracts, not even under pressureof cogent arguments, would hardly qualify as (...) areasonable discussant. Also, inconsistencies in one'sposition, once they have been pointed out, must bedealt with by some kind of retraction. The problem ofretraction is to find a suitable model of dialoguethat allows retractions where they seem reasonable, oreven required, and rules them out (or puts sanctionsupon them) whenever they would become disruptive of awell-organized process of dialogue.The present paper tries to point to a solution basedon the following principles: (1) Retraction rulesdetermine what retractions are permissible, and (2) ifpermissible what the consequences of retraction are.(3) Retraction rules vary according to the type ofdialogue and (4) according to the type of commitmentretracted. For instance, assertions and mereconcessions need to be distinguished, as well aslight-side and dark-side commitments. (5) To accountfor our contradictory intuitions on the issue ofretractions, one may best resort to a complex type ofdialogue in which different retraction rules hold fordifferent parts.The paper explains, summarizes, and expands upon thediscussion of retraction in Commitment inDialogue by Douglas Walton and the present author(cf. Walton and Krabbe 1995). (shrink)

This paper discusses several types of relevance criticism within dialogue. Relevance criticism is a way one could or should criticize one's partner's contribution in a conversation as being deficient in respect of conversational coherence. The first section tries to narrow down the scope of the subject to manageable proportions. Attention is given to the distinction between criticism of alleged fallacies within dialogue and such criticism as pertains to argumentative texts. Within dialogue one may distigguish tenability criticism, connection criticism, and narrow-type (...) relevance criticism. Only the last of these three types of criticism constitutes a charge of fallacy and carries with it a burden of proof. In the second it is observed that a full study of narrow-type relevance criticism would require the construction of complicated, many-layered, dialogue systems. Such a study can, however, be profitably preceded by setting up profiles of dialogue that help us discuss the ins and outs of certain types of move. This is illustrated with an example. (shrink)

The question of who has the burden of proof is often important in practice. We must frequently make decisions and act on the basis not of conclusive evidence but of what is reasonable to presume true. Consequently, it happens that a given practical question must be solved by referring to principles that explicitly or implicitly determine, at least partly, where the burden of proof should rest. In this essay, I consider the role of the logic of the burden of proof (...) in a debate on global justice. In particular, I ask how the logic of the burden of proof is seen by those who defend conservative positions in a debate and deny our obligations to reduce poverty beyond borders. I argue that defenders of conservative positions tend to shift the burden of proof in an unjustified way. (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)

In this paper the authors give a brief overview of the theoretical background of their research project “Linguistic indicators of argumentative moves.” Starting from the pragma-dialectical ideal model of a critical discussion, they design dialectical profiles for capturing the moves that may or must be made at a particular stage or sub-stage of such a discussion. They explain how these dialectical profiles can be methodically exploited for systematically identifying the verbal expressions that can be indicative of any of these moves (...) in argumentative practice. (shrink)