The three research questions of this study have been: what exactly is active ambiguity?; how should we assess active ambiguities in an argumentative discussion?; what does an adequate dialectical account of active ambiguity look like? These three questions have been answered by giving a definition of active ambiguity, and by elaborating on the properties of active ambiguity. Based on the survey of possible consequences of active ambiguities, and based on the basic division of labour in a persuasion dialogue, we arrived (...) at a set of requirements that a normative, procedural account of active ambiguity should satisfy. The model for ambiguity dialectic both provides a detailed account of evaluating active ambiguities, as well as a dialectical account of dealing with alleged active ambiguity. The distinction between constitutive and regulative rules for discussion has made it possible to provide a discussion model in which discussants can raise the issue of active ambiguity, and in which they can argue about the correctness of such points of order. This immanent dialectical approach has lead to a fourfold classification of fallacies: by using an actively ambiguous expression a party either violates a regulative, or a constitutive rule for persuasion dialogue, and if this party violates a rule, he or she either commits a fallacy of ambiguity, and possibly also the more complex fallacy of equivocation. This model for ambiguity dialectic has been shown to be useful for the analysis and evaluation of complex debates and discussions. The present study can be extended in various ways:  A model for critical discussion can be enriched so that it accommodates other regulative rules, such as the rule that requires arguments to be valid. By doing so, other points of order and other fallacy criticisms can be studied from the perspective of a critical metadiscussion.  The results concerning active ambiguity can be applied to other modes of reasoning, such as visual argumentation.  The results can be applied to ambiguity at the level of larger stretches of argumentative discourse. That could lead to a fruitful contribution to the theory of argument structures.  There still is a need for dialectical models that concern the use of usage declaratives different from providing a disambiguation, such as the use of definitions, clarifications of unfamiliar expressions, amplifications, etc., and the question would have to be answered how the rules with respect to active ambiguity would relate to those models.  The model can be enriched by inserting a specific ‘linguistic utterance meaning testing machine’. That would be a major step towards implementing the model in a computer program.  The use of descriptive profiles of dialogue could be improved further. In order to analyse the way parties respond to dialectically complex contributions, we are in need of a dialectical theory that provides the parties with specific rights and obligations for putting forward complex contributions and for responding to complex contributions. (shrink)

We are happy to present to the reader the first book of our Applied Logic Series. Walton's book on the fallacies of ambiguity is firmly at the heart of practical reasoning, an important part of applied logic. There is an increasing interest in artifIcial intelligence, philosophy, psychol ogy, software engineering and linguistics, in the analysis and possible mechanisation of human practical reasoning. Continuing the ancient quest that began with Aristotle, computer scientists, logicians, philosophers and linguists are vigorously seeking to deepen (...) our understanding of human reasoning and argumentation. Significant communities of researchers are actively engaged in developing new approaches to logic and argumentation, which are better suited to the urgent needs of today's applications. The author of this book has, over many years, made significant contributions to the detailed analysis of practical reasoning case studies, thus providing solid foundations for new and more applicable formal logical systems. We welcome Doug Walton's new book to our series. (shrink)

This investigation joins recent research on problems with ambiguity in two fields, argumentation and computing. In argumentation, there is a concern with fallacies arising from ambiguity, including equivocation and amphiboly. In computing, the development of agent communication languages is based on conversation policies that make it possible to have information exchanges on the internet, as well as other forms of dialogue like persuasion and negotiation, in which ambiguity is a problem. Because it is not possible to sharply differentiate between problems (...) arising from ambiguity and those arising from vagueness, obscurity and indeterminacy, some study of the latter is included. The semantic web is based on what are called ontologies, or systems of classification of concepts, shown to be useful tools for dealing with these problems. (shrink)

Persuasive definitions – those that convey an attitude in the act of naming – are frequently employed in discourse and are a form of strategic maneuvering. The dynamics of persuasive definition are explored through brief case studies and an extended analysis of the use of the “war” metaphor in responding to terrorism after September 11, 2001. Examining persuasive definitions enables us to notice similarities and differences between strategic maneuvering in dialectical and in rhetorical argument, as well as differences between the (...) role of strategic maneuvering in normatively ideal argument and in actually existing argument. This will avoid the double standard of comparing ideal dialectic with actual rhetoric, or vice versa. The results of the analysis suggest possibilities for a rapprochement between dialectical and rhetorical approaches to argumentation. (shrink)