In The Uses of Argument, Stephen Toulmin proposed a model for the layout of arguments: claim, data, warrant, qualifier, rebuttal, backing. Since then, Toulmin’s model has been appropriated, adapted and extended by researchers in speech communications, philosophy and artificial intelligence. This book assembles the best contemporary reflection in these fields, extending or challenging Toulmin’s ideas in ways that make fresh contributions to the theory of analysing and evaluating arguments.

J. Anthony Blair is a prominent international figure in argumentation studies. He is among the originators of informal logic, an author of textbooks on the informal logic approach to argument analysis and evaluation and on critical thinking, and a founder and editor of the journal Informal Logic. Blair is widely recognized among the leaders in the field for contributing formative ideas to the argumentation literature of the last few decades. This selection of key works provides insights into the history of (...) the field of argumentation theory and various related disciplines. It illuminates the central debates and presents core ideas in four main areas: Critical Thinking, Informal Logic, Argument Theory and Logic, Dialectic and Rhetoric. (shrink)

Consider the proposition, "Informal logic is a subdiscipline of philosophy". The best chance of showing this to be true is showing that informal logic is part of logic, which in turn is a part of philosophy. Part 1 is given over to the task of sorting out these connections. If successful, informal logic can indeed be seen as part of philosophy; but there is no question of an exclusive relationship. Part 2 is a critical appraisal of the suggestion that informal (...) logic is applied epistemology. Part 3 examines the claim that informal logic has failed to penetrate into mainstream philosophy, and suggestions for amelioration are considered. (shrink)

Relevance of premises to conclusion can be explicated through Toulmin’s notion of warrant, understood as an inference rule, albeit not necessarily formal. A normative notion of relevance requires the warrant to be reliable. To determine reliability, we propose a fourfold classification of warrants into a priori, empirical, institutional, and evaluative, with further subdivisions possible. This classification has its ancestry in classical rhetoric and recent epistemology. Distinctive to each type of warrant is the mode by which such connections are intuitively discovered (...) and the grounds on which we ultimately justify them. The classification of warrants is thus epistemic. We illustrate the difference by contrasting empirical physical with institutional intuition, and argue for the advantages of this approach over Toulmin’s conception of field dependence. (shrink)

Many in the informal logic tradition distinguish convergent from linked argument structure. The pragma-dialectical tradition distinguishes multiple from co-ordinatively compound argumentation. Although these two distinctions may appear to coincide, constituting only a terminological difference, we argue that they are distinct, indeed expressing different disciplinary perspectives on argumentation. From a logical point of view, where the primary evaluative issue concerns sufficient strength of support, the unit of analysis is the individual argument, the particular premises put forward to support a given conclusion. (...) Structure is internal to this unit. From a dialectical point of view, where the focus concerns how well a critical discussion comes to a reasoned conclusion of some disputed question, the argumentation need not constitute a single unit of argument. The unit of dialectical analysis will be the entire argumentation made up of these several arguments. The multiple/co-ordinatively compound distinction is dialectical, while the linked/convergent distinction is logical. Keeping these two pairs of distinctions separate allows us to see certain attempts to characterize convergent versus linked arguments as rather characterizing multiple versus co-ordinatively compound arguments, in particular attempts of Thomas, Nolt, and Yanal, and to resolve straightforwardly conflicts, tensions, or anomalies in their accounts. Walton's preferred Suspension/Insufficient Proof test to identify linked argument structure correctly identifies co-ordinatively compound structure. His objection to using the concept of relevance to explicate the distinction between linked and convergent structure within co-ordinatively compound argumentation can be met through explicating relevance in terms of inference licenses. His counterexample to the Suspension/No Support test for identifying linked structure which this approach supports can itself be straightforwardly dealt with when the test is explicated through inference licenses. (shrink)

Premissary relevance is a property of arguments understood as speech act complexes. It is explicable in terms of the idea of a premise's lending support to a conclusion. Premissary relevance is a function of premises belonging to a set which authoritatively warrants an inference to a conclusion. An authoritative inference warrant will have associated with it a conditional proposition which is true— that is to say, which can be justified. The study of the Aristotelian doctrine of topoi or argument schemes (...) may contribute to the task of identifying authoritative warrants. (shrink)

In this overview article, we first explain what we take informal logic to be, discussing misconceptions and distinguishing our conception of it from competing ones; second, we briefly catalogue recent informal logic research, under 14 headings; third, we suggest four broad areas of problems and questions for future research; fourth, we describe current scholarly resources for informal logic; fifth, we discuss three implications of informal logic for philosophy in particular, and take note ofpractical consequences of a more general sort.

My project is a systematic inquiry into the problem of relevance, which has been identified as an enduring difficulty in, for example, informal logic and information science where it plays a fundamental role in argument and information searches, respectively. My first task involves determining exactly what the problem of relevance is. To achieve that, I collected problem statements from the literature but I also analysed literature on relevance to discover further problems. The key problem that I investigate concerns the question, (...) 'What is relevance?', which I take to concern the meaning and occurrence of relevance. Concerning the semantic question, I suggest that it demarcates a point of time prior to asking it. Subsequently, I identified and evaluated approaches to elucidating the notion of relevance, rejected intuitionism and stipulation as suitable approaches, and selected philosopher/physicist Mario Bunge's approach to scientific philosophy and his conceptual system to frame my study. I also assess potential information sources; rejected constructed examples that prove to be contrived or are used to illustrate a stipulated definition; and selected dictionary definitions, actual statements, and carefully constructed examples as information sources to complement my review of the literature on relevance. To elucidate relevance, I traced the concept back to its Greek roots, analysed statements, and concluded that the term 'relevance' since its inception in Scottish law in the early 1500's has been limited largely to relations of significance. Understanding relevance in terms of both connection and significance is crucial to construct, identify, or evaluate relevance statements and thereby develop a representative theory of relevance. It also provides a solution to many controversies such as degree of relevance and it helps elucidate notions such as strength and sufficiency of an argument. I suggest that as significance can vary in degree, so too can relevance but a connection between objects is presupposed in both cases. Strength is a measure of significance and sufficiency is the strength required to establish a conclusion. Finally, I offer a provisional and partial theory of relevance where I summarize my prior analyses and integrate/comment on published positions on relevance. (shrink)

Moral dissensus may arise first because persons may disagree over the warrants licensing inferring an evaluative conclusion from premises asserting that properties alleged evaluatively relevant hold. This results in seeing different properties as evaluatively relevant. Secondly, such properties will frequently not be descriptive but interpretive, asserting some nomic connection. Persons may disagree over what evaluatively relevant properties hold in a given case. We explore the possibilities for argumentation to resolve these two types of disagreement.

This paper presents the concept of relevance in argumentation theory analyzed from a pragma-rhetorical angle. Special attention will be given to examples in which relevance is determined by the extended social context of the use of presentational devices in controversies. The analysis of examples will include the rhetorical concept of decorum, maintaining that a different emphasis should be given to the role of the speaker in the determination of relevance.

Suppose two persons disagree over whether an act is right, justifying their judgments by appealing to divergent higher-level moral principles. These principles function as backing and rebuttals in their argumentation. To justify these principles, we may argue either that they would be accepted in some ideal model or that they are in reflective equilibrium with our considered moral judgments. Disagreement over the model indicates difference in philosophical anthropology but does not preclude resolution through argument.