Showing papers by "Douglas Walton published in 2008"

Advances in the Theory of Argumentation Schemes and Critical Questions

Abstract: 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.

The Argumentative Structure of Persuasive Definitions

Abstract: 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.

A Dialogical Theory of Presumption

Abstract: The notions of burden of proof and presumption are central to law, but as noted in McCormick on Evidence, they are also the slipperiest of any of the family of legal terms employed in legal reasoning. However, recent studies of burden of proof and presumption offer formal models that can render them into precise tools useful for legal reasoning. In this paper, the various theories and formal models are comparatively evaluated with the aim of working out a more comprehensive theory that can integrate the components of the argumentation structure on which they are based. It is shown that the notion of presumption has both a logical component and a dialectical component, and the new theory of presumption developed in the paper, called the dialogical theory, combines these two components.

Evaluating Corroborative Evidence

Abstract: How should we evaluate an argument in which two witnesses independently testify to some claim? In fact what would happen is that the testimony of the second witness would be taken to corroborate that of the first to some extent, thereby boosting up the plausibility of the first argument from testimony. But does that commit the fallacy of double counting, because the second testimony is already taken as independent evidence supporting the claim? Perhaps the corroboration effect should be considered illogical, since each premise should be seen as representing a separate reason in a convergent argument for accepting the claim as plausible. In this paper, we tackle the problem using argumentation schemes and argument diagramming. We examine a number of examples, and come up with two hypotheses that offer methods of analyzing and evaluating this kind of evidence.

A dialogical theory of presumption

Abstract: The notions of burden of proof and presumption are central to law, but as noted in McCormick on Evidence, they are also the slipperiest of any of the family of legal terms employed in legal reasoning. However, recent studies of burden of proof and presumption (Prakken et al. 2005; Prakken and Sartor 2006). Gordon et al. (2007) offer formal models that can render them into precise tools useful for legal reasoning. In this paper, the various theories and formal models are comparatively evaluated with the aim of working out a more comprehensive theory that can integrate the components of the argumentation structure on which they are based. It is shown that the notion of presumption has both a logical component and a dialectical component, and the new theory of presumption developed in the paper, called the dialogical theory, combines these two components.

The Argumentative Structure of Persuasive Definitions

Abstract: 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.

Persuasive Definitions: Values, Meanings and Implicit Disagreements

Abstract: The purpose of this paper is to inquire into the relationship between persuasive definition and common know-ledge (propositions generally accepted and not subject to dispute in a discussion) We interpret the gap between common knowledge and persuasive definition (PD) in terms of potential disagreements: PDs are conceived as implicit arguments to win a potential conflict Persuasive definitions are analyzed as arguments instantiating two argumentation schemes, argument from classification and argu-ment from values, and presupposing a potential disagreement The argumen-tative structure of PDs reveals different levels of disagreement, and different pos-sibilities of resolving the conflict or causing dialogical deadlock

Argument from Definition to Verbal Classification: The Case of Redefining 'Planet' to Exclude Pluto

Abstract: The recent redefinition of 'planet' that excludes Pluto as a planet led to controversy that provides a case studyof how competing scientific definitions can be supported by characteristic types of evidence. Using tools from argumentation and AI, it is shown how argumentation schemes, in particular argument from verbal classification and argument from definition to verbal classification, apply to cases of scientific argumentation.

Arguing from Definition to Verbal Classification: The Case of Redefining 'Planet' to Exclude Pluto

Abstract: The recent redefinition of 'planet' that excludes Pluto as a planet led to controversy that provides a case study of how competing scientific definitions can be supported by characteristic types of evidence. An argumentation scheme from Hastings is used to analyze argument from verbal classification as a form of inference used in rational argumentation. The Toulmin-style format is compared to more recently developed ways of modeling such cases that stem from advances in argumentation technology in artificial intelligence. Usingthese tools, it is shown how argumentation schemes, in particularargument from verbal classification and argument from definition to verbal classification, apply to cases of scientific argumentation.

Persuasive Definitions: Values, Meanings and Implicit Disagreements

Abstract: The purpose of this paper is to inquire into the relationship between persuasive definition and common knowledge (propositions generally accepted and not subject to dispute in a discussion). We interpret the gap between common knowledge and persuasive definition (PD) in terms of potential disagreements: PDs are conceived as implicit arguments to win a potential conflict. Persuasive definitions are analyzed as arguments instantiating two argumentation schemes, argument from classification and argument from values, and presupposing a potential disagreement. The argumentative structure of PDs reveals different levels of disagreement, and different pos-sibilities of resolving the conflict or causing dialogical deadlock.

Defeasibility in Judicial Opinion: Logical or Procedural?

Abstract: 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. Resume: Malgre les etudes recentes sur la defaisabilite dans le raisonnement legal, on ne l'a pas encore etudiee dans le contexte de l'opinion judiciaire. Une decision judiciaire, quoique sujette a un jugement en appel, peut etre defaite pour une variete de raisons. Pakken (2001) a soutenu qu'une analyse procedurale de la defaisabilite d'un raisonnement dans une argumentation legale antagoniste est meilleure qu'une analyse logique. De facon semblable, un encadrement procedural et dialectique explique et illustre mieux la defaisabilite de ratio decendi. Nous proposons que des jugements en appel soient mieux entendus comme des meta-dialogues sur les raisonnements avances dans le proces- mem

Argumentation Schemes: Schemes for Argument from Analogy, Classification, and Precedent

Abstract: Argument from analogy is one of the fundamental forms of argumentation on which many other forms of argument – argument from precedent in law, for example – are based (Gordon, 1995; Weinreb, 2005). Our system of Anglo-American law is based on ratio decidendi , the principle that if a case has been decided by a court in a certain way, then a new case that is similar to it should be decided in the same way. Indeed, argument from analogy is the foundation of all case-based reasoning (CBR) in which the argumentation turns on a comparison of one case to another (Ashley and Rissland, 2003). CBR not only compares one case to another as similar, but also compares cases as more similar to others with respect to a given case, depending on the description of the problem posed in the given case. Thus argument from analogy is an extremely important and fundamental species of argumentation. So much has been written on it, in so many fields, including philosophy, cognitive science, artificial intelligence, linguistics, psychology, law, and computing, that we can barely scratch the surface here. Our more limited aim is to develop tools that can be used to identify the precise form of arguments from analogy, allowing us to better understand its close relationships with other important schemes, especially those representing argument from verbal classification and argument from precedent.

Argumentation Schemes: A User's Compendium of Schemes

Abstract: In this chapter a compendium of all the schemes discussed is given, along with the source of the scheme in the argumentation literature We have tried to make the compendium most useful to the reader by presenting the schemes that represent the most commonly used forms of argument, including not only those used in everyday discourse, but also certain schemes that are important in legal and scientific reasoning Many of these schemes have subtypes, and research on the classification of the subtypes, and even more generally, research on determining which schemes are subspecies of other schemes, is not yet at an advanced stage Thus while we have made occasional remarks on these matters, hoping to provide some insight, we have not generally listed all the known subspecies of the schemes There are two especially important exceptions that need to be noted We have included a fairly comprehensive account of the known subschemes of the argument from popular opinion, to give the reader an idea of how it can be important to recognize many of these different subschemes in dealing with common arguments of the type associated with informal fallacies The other important exception is the case of the argumentum ad hominem Many subschemes for this type of argument have been recognized, and much work on trying to organize and classify them has been conducted (Walton, 1998)