This investigation uses the technique of the profile of dialogue as a tool for the evaluation of arguments from ignorance (also called lack-of-evidence arguments, negative evidence, ad ignorantiam arguments and ex silentio arguments). Such arguments have traditionally been classified as fallacies by the logic textbooks, but recent research has shown that in many cases they can be used reasonably. A profile of dialogue is a connected sequence of moves and countermoves in a conversational exchange of a type that is goal-directed (...) and can be represented in a normative model of dialogue. Selected case studies are used to probe special features of using the profile technique as applied to arguments from ignorance of a kind that occur frequently in everyday conversational exchanges. One of these special features is the use of Gricean implicature. Another is the need to use negative profiles of argument. (shrink)

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)

Van Eemeren and Houtlosser observe that Walton’s (and Walton and Krabbe’s) notion of ‘dialogue type’ involves a mixture of an empirical notion on a par with a speech event or activity type and a normative notion such as the model of a critical discussion. Then they discuss Walton’s contextual analysis of fallacies as illegitimate dialectical shifts of dialogue types and offer an alternative in which both the empirical and the normative dimension are given their due.

False dilemma is a specific form of reasoning : despite the fact that it is based on a deductively valid argument form, it is rightly depicted as fallacy. A systematic exposition of false dilemma is missing in theoretical approaches to fallacies. This article formulates six criteria for a well-grounded exposition of a fallacy, suggesting also a systematic exposition of false dilemma. These criteria can be used to both explain, and categorise, the various false dilemma fallacies. The article introduces distinction between (...) four types of false dilemma : False quandary, Defeasible sound quandary, False obstruction and Defeasible sound obstruction. The types of criticism appropriate for each variant of false dilemma are suggested. Being able to discover false dilemma in situations when it is important to make good and free choices is a significant dimension of critical thinking. It may liberate us from accepting the consequences that necessarily follow from prearranged alternatives, when these are not the only alternatives possible. It may also liberate us from refraining from actions on the basis of obstructive disjunctive statements. In that respect, the faculty of critical thinking directed at uncovering reasoning based on false dilemma may also initiate the discovery of new alternatives, or discover the ways of unifying seemingly opposing alternatives. Thus, a well-developed ability to understand the tricky argumentative moves of false dilemma may be a good step towards initiating some features of creative thinking. (shrink)

In this paper, I try to develop an informal model for the analysis and evaluation of argumentative strategies based on active authorities. The explanations necessary to understand the idea of the model and what is modelled are given through the development of the paper. I first give an example of argumentative activities. After that, the main assumption of the model is given. In the third part, the relevant aspects of the argumentative activity are analysed, while the principles of the evaluation (...) are explained in the fourth part. The informal model is presented in the fifth part. In the final remarks, the suggestions for further work are given, as well as a comparison with some related recent works in argumentation theory. (shrink)

This paper outlines an integrated approach to trust and relevance with respect to arguments: in particular, it is suggested that trust in relevance has a central role in argumentation. We first distinguish two types of argumentative relevance: internal relevance, i.e. the extent to which a premise has a bearing on its purported conclusion, and external relevance, i.e. a measure of how much a whole argument is pertinent to the matter under discussion, in the broader dialogical context where it is proposed. (...) Then, we argue that judgements of internal relevance heavily rely on trust, and that such trust, although occasionally misplaced , is nonetheless based on several reasons, and thus often justified, by either epistemic or pragmatic considerations. We conclude by sketching potential methods to formally model trust in argumentative relevance, and briefly discussing the technological implications of this line of research. (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)

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)

Using the profiles of dialogue method we identify a species of ad verecundiam fallacy that works by forestalling of questioning in arguments from expert opinion. A profile of dialogue is a graph structure used to model a sequence of speech acts surrounding both the putting forward of an argument and the response to it at the next moves in a dialogue. The method is applied to a case of cross-examining a software engineer in a legal deposition in a case of (...) intellectual property litigation. (shrink)

In this article, I further analyze the notion of the effectiveness of argumentative strategies, introduced in Jovičić, 2001. The most relevant achievements of the theories of reasonable discussion and the theories of persuasion are called to mind with the aim of explaining the mechanism of the argumentative effectiveness. As a result, a procedure for evaluating the effectiveness of argumentative strategies is suggested.

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)