Douglas Walton

(? - 2020)

The aim of this investigation is to explore the role of argumentation schemes in enthymeme reconstruction. This aim is pursued by studying selected cases of incomplete arguments in natural language discourse to see what the requirements are for filling in the unstated premises and conclusions in some systematic and useful way. Some of these cases are best handled using deductive tools, while others respond best to an analysis based on defeasible argumentations schemes. The approach is also shown to work reasonably well for weak arguments, a class of arguments that has always been difficult to analyze without the principle of charity producing a straw man.

This paper begins a working through of Blair’s (2001) theoretical agenda concerning argumentation schemes and their attendant critical questions, in which we propose a number of solutions to some outstanding theoretical issues. We consider the classification of schemes, their ultimate nature, their role in argument reconstruction, their foundation as normative categories of argument, and the evaluative role of critical questions.We demonstrate the role of schemes in argument reconstruction, and defend a normative account of their nature against specific criticisms due to Pinto (2001). Concerning critical questions, we propose an account on which they are founded in the R.S.A. cogency standard, and develop an account of the relationship between critical questions and burden of proof. Our ultimate aim is to initiate a reconciliation between dialectical and informal logic approaches to the schemes

In this paper we present an analysis of persuasive definition based on argumentation schemes. Using the medieval notion of differentia and the traditional approach to topics, we explain the persuasiveness of emotive terms in persuasive definitions by applying the argumentation schemes for argument from classification and argument from values. Persuasive definitions, we hold, are persuasive because their goal is to modify the emotive meaning denotation of a persuasive term in a way that contains an implicit argument from values. However, our theory is different from Stevenson’s, a positivistic view that sees emotive meaning as subjective, and defines it as a behavioral effect. Our proposal is to treat the persuasiveness produced by the use of emotive words and persuasive definitions as due to implicit arguments that an interlocutor may not be aware of. We use congruence theory to provide the linguistic framework for connecting a term with the function it is supposed to play in a text. Our account allows us to distinguish between conflicts of values and conflicts of classifications.

The distinction between action persuasion dialogues and deliberation dialogues is not always obvious at first sight. In this paper, we provide a characterisation of both types of dialogues that draws out the distinctive features of each. It is important to recognise the distinctions since participants in both types of dialogues will have different aims, which in turn affects whether a successful outcome can be reached. Such dialogues are typically conducted by exchanging arguments for and against certain options. The moves of the dialogue are designed to facilitate such exchanges. In particular, we show how the pre- and post-conditions for the use of particular moves in the dialogues are very different depending upon whether they are used as part of a persuasion over action or a deliberation dialogue. We draw out the distinctions with reference to a running example that we also present as a logic program in order to give a clear characterisation of the two types of dialogues, which is intended to enable them to be used more effectively within systems requiring automated communication.

This article evaluates the strengths and weaknesses of arguments based on appeals to expertise. The intersection of two areas is explored: (i) the traditional argumentum ad verecundiam (literally, “appeal to modesty,” but characteristically the appeal to the authority of expert judgment) in informal logic, and (ii) the uses of expert systems in artificial intelligence. The article identifies a model of practical reasoning that underlies the logic of expert systems and the model of argument appropriate for the informal logic of the argumentum ad verecundiam

In this paper we show how dialogue-based theories of argumentation can contribute to the construction of effective systems of dispute resolution. Specifically we consider the role of persuasion in online dispute resolution by showing how persuasion dialogues can be functionally embedded in negotiation dialogues, and how negotiation dialogues can shift to persuasion dialogues. We conclude with some remarks on how persuasion dialogues might be modelled is such a way as to allow them to be implemented in a mechanical or computerized system of dialogue or dialogue management.

The aims of this paper are to survey, explicate, compare, contrast, and critically evaluate a number of (mainly recent and technical) contributions (Kanger, Porn and Áqvist) to the logic of action locutions in connection with their treatment of the concept of an agent's bringing about a state of affairs. The discussion is primarily concerned with practical applications of these formalisms for the action theorist. It is suggested that these systems are best understood as capturing a strategic sense of bringing-about, and not a notion of actual bringing-about, which is merely presupposed by them. It is argued that the developments surveyed open up a new 'intensional' style of action theory, contrasted with the 'extensional' approach of Davidson. Yet because of the treatment of conditionals, they fail to capture a basic notion of 'bringing about' important for action theory. It is concluded that a study of the behavior of 'bringing-about' over non-standard conditionals would be a useful next step for intensional action logic.

This paper presents a formalization of informal logic using the Carneades Argumentation System, a formal, computational model of argument that consists of a formal model of argument graphs and audiences. Conflicts between pro and con arguments are resolved using proof standards, such as preponderance of the evidence. CAS also formalizes argumentation schemes. Schemes can be used to check whether a given argument instantiates the types of argument deemed normatively appropriate for the type of dialogue.

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

In a critical study of some recent action theory Professor James Tomberlin [7] makes some insightful and suggestive remarks concerning the by now well known problem of "Smith and the airplane" formulated by Keith Lehrer and Richard Taylor [3]. While these remarks do significantly advance our knowledge of the nature of the problem, I would like to try to show why the strategy they indicate does not lead to a solution that represents any improvement on the one developed in [1], [8] and [2].The problem of Smith and the airplane is posed by the following apparent inconsistency. Suppose it is now shortly before 3:30 and Smith is at a country airport. The 3:30 plane is the only possible means whereby Smith can arrive at the city at 4:00. There is nothing to prevent Smith from leaving on the 3:30 plane, but he in fact does not do so: Then each of the following statements are true.

While courts depend on expert opinions in reaching sound judgments, the role of the expert witness in legal proceedings is associated with a litany of problems. Perhaps most prevalent is the question of under what circumstances should testimony be admitted as expert opinion. We review the changing policies adopted by American courts in an attempt to ensure the reliability and usefulness of the scientific and technical information admitted as evidence. We argue that these admissibility criteria are best seen in a dialectical context as a set of critical questions of the kind commonly used in models of argumentation.

G. H. R. Parkinson, The Renaissance and Seventeenth-century Rational-ism London and New York:Routledge, 1993. xxix + 444 pp. £55.00 J. Pafel, Subjekt, Prädikat, Objekt, Eine semantische Definition grammatischer Funktionen, Frankfurt am Main:Peter Lang, 1991. 166 pp Dieter Munch, Intention und Zeichen, Untersuchungen zu Franz Brentano und zu Edmund Husserls Frühwerk. Frankfurt am Main:Suhrkamp, 1993, v+324 pp. DM 42 J, Lameer, Al-Farabi & Aristotelian syllogistics:Greek theory & Islamic practice. Leiden: E, J. Brill, 1994. xx + 351 pp. Nig. 130.00/$74.50 F. H. Bradley, Writings on Logic and Metaphysics, edited by James W. Allard and Guy Stock, Oxford, Clarendon Press, 1994. xv and 357 pp. £40, £14.95 Christoph Kann, Die Eigenschaften der Termini:Eine Untersuchung zur Per-uulis Logica Alberts von Sachsen, Leiden, New York, Köln: Brill, 1994. 267 pp. Hfl. 120 $68.7 Robert C. Solomon and Kathleen M. Higgins, The age of German Idealism.. 1994, London and New York:Routledge, xxv + 408 pp. £55.00 K. Dorter, Form and Good in Plato's Eleatic Dialogues, Berkeley:University of California Press, 1994. x + 256pp. $45.00 Stephen Read, Thinking about logic:an introduction to the philosophy of logic, Oxford: Oxford University Press, 1995. vii + 262 pp. £8.99 G. Boolos, The logic of provability. Cambridge, New York, and Melbourne:Cambridge University Press, 1993. xxxvi + 276 pp. $59.95 Kathleen Johnson Wu, Discovering formal logic. Guilford, Connecticut:The Dushkin Publishing Group, Inc., 1994. xxiv + 529 pp. $32.95 Kevin L. Flannery, S. J., Ways into the logic of Alexander of Aphrodisias, Leiden:E. J. Brill, 1995. xxiv + 170 pp José Ferreirós Domínguez, El Nacimiento de la Teoria de Conjuntos, 1854-1908. Madrid:Universidad Autönoma, 1993, 394 pp. No price stated Nathalie Charraud, Infini et inconscient. Essai sur Georg Cantor. Paris:Anthropos, 1994. 299 pp. 190F John G. Slater, Bertrand Russell. Bristol, U.K.:Thoemmes Press, 1994. xii + 171 pp. No price stated Stefan Andersson In quest of certainty, Bertand Russell's search for certainty in religion and mathematics up to "The principles of mathematics", Stockholm:Almqvist and Wilksell International, 1994. xiii + 192 pp. No price stated Karl Menger, Reminiscences of the Vienna Circle and the Mathematical Colloquium, Edited by Louise Golland, Brian McGuinness and Abe Sklar. Dordrecht, Boston and London:Kluwer Academic Publishers, 1994. xxvi + 244 pp. No price stated Sun-Joo Shin, The Logical Status of Diagrams. Cambridge, UK, and New York:Cambridge University Press, 1994. xi + 197 pp. $39.95

This book provides an argumentation model for means-end reasoning, a distinctive type of reasoning used for problem-solving gand decision-making. Means-end reasoning is modeled as goal-directed argumentation from an agent's goals and known circumstances, and from an action selected as a means, to a decision to carry out the action. Goal-based reasoning for argumentation provides an argumentation model for this kind of reasoning, showing how it is employed in settings of intelligent deliberation where agents try to collectively arrive at a conclusion on what they should do to move forward in a set of circumstances. The book explains how this argumentation model can help build more realistic computational systems of deliberation and decision-making and shows how such systems can be applied to solve problems posed by goal-based reasoning in numerous fields, from social psychology and sociology, to law, political science, anthropology, cognitive science, artificial intelligence, multi-agent systems, and robotics." -- Back cover.

While defeasibility in legal reasoning has been the subject of recent scholarship, it has yet to be studied in the context of judicial opinion. Yet, being subject to appeal, judicial decisions can default for a variety of reasons. Prakken (2001) argued that the defeasibility affecting reasoning involved in adversarial legal argumentation is best analysed as procedural rather than logical. In this paper we argue that the defeasibility of ratio decendi is similarly best explained and modeled in a procedural and dialectical framework. We propose that appeals are best understood as meta-dialogues about the reasoned dialogue occurring in the initial trial

This paper explains the importance of classifying argumentation schemes, and outlines how schemes are being used in current research in artificial intelligence and computational linguistics on argument mining. It provides a survey of the literature on scheme classification. What are so far generally taken to represent a set of the most widely useful defeasible argumentation schemes are surveyed and explained systematically, including some that are difficult to classify. A new classification system covering these centrally important schemes is built.

The representation and classification of the structure of natural arguments has been one of the most important aspects of Aristotelian and medieval dialectical and rhetorical theories. This traditional approach is represented nowadays in models of argumentation schemes. The purpose of this article is to show how arguments are characterized by a complex combination of two levels of abstraction, namely, semantic relations and types of reasoning, and to provide an effective and comprehensive classification system for this matrix of semantic and quasilogical connections. To this purpose, we propose a dichotomous criterion of classification, transcending both levels of abstraction and representing not what an argument is but how it is understood and interpreted. The schemes are grouped according to an end-means criterion, which is strictly bound to the ontological structure of the conclusion and the premises. On this view, a scheme can be selected according to the intended or reconstructed purpose of an argument and the possible strategies that can be used to achieve it.

Appeals to emotion—pity, fear, popular sentiment, and _ad hominem_ attacks—are commonly used in argumentation. Instead of dismissing these appeals as fallacious wherever they occur, as many do, Walton urges that each use be judged on its merits. He distinguished three main categories of evaluation. First, is it reasonable, even if not conclusive, as an argument? Second, is it weak and therefore open to critical questioning for argument? And third, is it fallacious? The third category is a strong charge that incurs a critical burden to back it up by citing evidence from the given text and context of dialogue. Walton uses fifty-six case studies to demonstrate that the problem of emotional fallacies is much subtler than has been previously believed. Ranging over commercial advertisements, political debates, union-management negotiations, and ethical disputes, the case studies reveal that these four types of appeals, while based on presumptive reasoning that are tentative and subject to default, are not always or necessarily fallacious types of argumentation

This paper builds a nine-step method for determining whether a straw man fallacy has been committed in a given case or not, by starting with some relatively easy textbook cases and moving to more realistic and harder cases. The paper shows how the type of argument associated with the fallacy can be proved to be a fallacy in a normative argumentation model, and then moves on to the practical task of building a hands-on method for applying the model to real examples of argumentation. Insights from linguistic pragmatics are used to distinguish the different pragmatic processes involved in reconstructing what is said and what is meant by an utterance, and to differentiate strong and weak commitments. In particular, the process of interpretation is analyzed in terms of an abductive pattern of reasoning, based on co-textual and contextual information, and assessable through the instruments of argumentation theory.

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.

In this paper it is shown how certain defeasible argumentation schemes can be used to represent the logical structure of the most common types of argument used for statutory interpretation both in civil and common law. The method is based on an argumentation structure in which the conclusion, namely, the meaning attributed to a legal source, is modeled as a claim that needs that is be supported by pro and con defeasible arguments. The defeasible nature of each scheme is shown by means of critical questions, which identify the default conditions for the accepting interpretative arguments and provide a method for evaluating a given argument as weak or strong.

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.