semantic minimalism and moderte contextualism.

In this paper, we present a survey of the development of the technique of argument diagramming covering not only the fields in which it originated - informal logic, argumentation theory, evidence law and legal reasoning – but also more recent work in applying and developing it in computer science and artificial intelligence. Beginning with a simple example of an everyday argument, we present an analysis of it visualised as an argument diagram constructed using a software tool. In the context of (...) a brief history of the development of diagramming, it is then shown how argument diagrams have been used to analyze and work with argumentation in law, philosophy and artificial intelligence. (shrink)

Corroborative evidence has a dual function in argument. Primarily, it functions to provide direct evidence supporting the main conclusion. But it also has a secondary, bolstering function which increases the probative value of some other piece of evidence in the argument. This paper argues that the bolstering effect of corroborative evidence is legitimate, and can be explained as counter–rebuttal achieved through inference to the best explanation. A model (argument diagram) of corroborative evidence, representing its structure and operation as a schematic (...) pattern of defeasible argument is also supplied. In addition to explaining the operation and theoretical foundation of corroborative evidence, the model facilitates the correct analysis and guides the evaluation (assessment and critique) of corroborative evidence as it occurs in argument. (shrink)

We argue that Cohen’s concept of inductive or ampliative probability facilitates proper explication of sufficient strength for non-demonstrative arguments conforming to the Toulmin model. The data and claims of such arguments are singular statements. We may epistemically classify the warrants of such arguments as empirical (either physical or personal), institutional, or evaluative. Backing evidence and rebutting considerations vary with the epistemic type of warrant, but in each case the notion of ampliative probability for arguments with warrants of that type can (...) be characterized. We may then use ampliative probability to define sufficient strength and related notions for Toulmin arguments. (shrink)

A critical examination of the dialectical approach, focusing on a comparison ofthe illative and the dialectical definitions of argument. I distinguish a moderate, a strong and a hyper dialectical conception of argument. I critique Goldman's argument for the moderate conception and Johnson's argument for the strong conception, and argue that the moderate conception is correct.

Logicians disagree on (1) criteria for the presence of an argument, (2) criteria for adding implicit premises and (3) criteria for linking premises. I attempt to resolve all three problems, and in the process to remove the main obstacles to teaching diagramming. The first problem is resolved by working with real discourse that students find on their own, rather than the artificial examples and problems found in logic texts; it is further reduced by examining the different uses of argument and (...) understanding the extent to which the basic rules of diagramming are the same for the various uses. The other disagreements persist because logicians neglect to clarify the principal type of eakness we remedy by adding implicit premises and linking premises: in real discourse we do so to block substantive counterexamples, an idea correlated with that of substantive deduction, discussed by Govier, Wright and others. (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.

A generation before Beardsley, legal scholar John Henry Wigmore invented a scheme for representing arguments in a tree diagram, aimed to help advocates analyze the proof of facts at trial. In this essay, I describe Wigmore's "Chart Method" and trace its origin and influence. Wigmore, I argue, contributes to contemporary theory in two ways. His rhetorical approach to diagramming provides a novel perspective on problems about the theory of reasoning, premise adequacy, and dialectical obligations. Further, he advances a novel solution (...) to the problem of assessing argument quality by representing the strength of argument in meeting objections. (shrink)

In this paper, a survey is presented of the main approaches to the structure of argumentation. The paper starts with a historical overview of the distinctions between various types of argument structure. Next, the main definitions given in the various approaches are discussed as well as the methods that are proposed to deal with doubtful cases.

Naszym celem jest dostarczenie formalnego modelu oceny możliwie szerokiej klasy argumentacji, w szczególności tych, które pojawiają się w kontekstach naturalnych. We wprowadzeniu przedstawiamy elementarne sposoby rozbudowywania argumentacji prostych w coraz bardziej złożone struktury. W drugim rozdziale podajemy ścisłe definicje pojęć służących do opisu tych struktur — argumentację definiujemy jako niepusty i skończony zbiór sekwentów, tj. jako niepustą i skończoną relację zachodzącą pomiędzy niepustymi i skończonymi zbio-rami zdań a pojedynczymi zdaniami danego języka; wprowadzamy także kilka pojęć (nie-spójność, rozbieżność, kolistość), które pozwalają (...) wyróżniać niektóre nietypowe lub wadliwe struktury argumentacyjne. W trzecim rozdziale proponujemy ogólną, liczbową metodę oceny siły argumentacji. Metoda ta pokazuje, jak wiarygodność przesłanek pierwszych przekłada się na wiarygodność konkluzji głównej w zależności od budowy argumentacji (wiarygodność wyrażamy za pomocą liczb wymiernych z domkniętego przedziału <0, 1>). Jedną z charakterystycznych własności argumentacji potocznej jest występowanie w niej wzajemnie wzmacniających się tzw. rozumowań równoległych. Dlatego za istotny składnik proponowanej metody należy uznać wzór: a * b = 2a+2b-2ab-1. Wzór ten pozwala obliczyć wiarygodność (konkluzji) dowolnej argumentacji równoległej, składającej się z dwóch wzajemnie niezależnych rozumowań, które brane z osobna uwiarygodniają konkluzję w stopniach a oraz b (zakładamy przy tym, że obie te wartości są większe niż ½). (shrink)

SummaryThis paper studies some classic cases of the fallacy of begging the question based on appeals to testimony containing circular reasoning. For example, suppose agents a, b and c vouch for d’s credentials, and agents b, d, and e vouch for a’s credentials. Such a sequence of reasoning is circular because a is offering testimony for d but d is offering testimony for a. The paper formulates and evaluates restrictions on the use of testimonial evidence that might be used to (...) deal with such problematic arguments. One is called the Non-repeater Rule: in an extended sequence of argumentation based on testimony, once a source x has been appealed to at any given point in the sequence, that same source x must never be appealed to again at any next point in the same sequence. (shrink)

The Toulmin diagram layout is very familiar and widely used, particularly in the teaching of critical thinking skills. The conventional box-and-arrow diagram is equally familiar and widespread. Translation between the two throws up a number of interesting challenges. Some of these challenges (such as the relationship between Toulmin warrants and their counterparts in traditional diagrams) represent slightly different ways of looking at old and deep theoretical questions. Others (such as how to allow Toulmin diagrams to be recursive) are diagrammatic versions (...) of questions that have already been addressed in artificial intelligence models of argument. But there are further questions (such as the relationships between refutations, rebuttals and undercutters, and the roles of multiple warrants) that are posed as a specific result of examining the diagram inter-translation problem. These three classes of problems are discussed. To the first class are addressed solutions based on engineering pragmatism; to the second class, are addressed solutions drawn from the appropriate literature; and to the third class, fuller exploration is offered justifying the approaches taken in developing solutions that offer both pragmatic utility and theoretical interest. Finally, these solutions are explored briefly in the context of the Araucaria system, showing the ways in which analysts can tackle arguments either using one diagrammatic style or another, or even a combination of the two. (shrink)

We provide a retrospective of 25 years of the International Conference on AI and Law, which was first held in 1987. Fifty papers have been selected from the thirteen conferences and each of them is described in a short subsection individually written by one of the 24 authors. These subsections attempt to place the paper discussed in the context of the development of AI and Law, while often offering some personal reactions and reflections. As a whole, the subsections build into (...) a history of the last quarter century of the field, and provide some insights into where it has come from, where it is now, and where it might go. (shrink)

The paper is a contribution to the debate on the epistemological status of thought experiments. I deal with the epistemological uniqueness of experiments in the sense of their irreducibility to other sources of justification. In particular, I criticize an influential argument for the irreducibility of thought experiments to general arguments. First, I introduce the radical empiricist theory of eliminativism, which considers thought experiments to be rhetorically modified arguments, uninteresting from the epistemological point of view. Second, I present objections to the (...) theory, focusing on the critique of eliminativism by Tamar Szabó Gendler based on the reconstruction of famous Galileo's Pisa experiment. I show that her reconstruction is simplistic and that more elaborate reconstruction is needed for an appropriate assessment of the epistemic power of general argument. I propose such a reconstruction and demonstrate that general version of Pisa experiment is epistemically equal to the particular one. Thus, from an epistemological perspective, Galileo's thought experiment is reducible to a straightforward argument without particular premises. (shrink)

This is a critical examination of Antoine Arnauld's Logic or the Art of Thinking (1662), commonly known as the Port-Royal Logic. Rather than reading this work from the viewpoint of post-Fregean formal logic or the viewpoint of seventeenth-century intellectual history, I approach it with the aim of exploring its relationship to that contemporary field which may be labeled informal logic and/or argumentation theory. It turns out that the Port-Royal Logic is a precursor of this current field, or conversely, that this (...) field may be said to be in the same tradition. (shrink)

We develop conceptions of arguments and of argument types that will, by serving as the basis for developing a natural classification of arguments, benefit work in artificial intelligence. Focusing only on arguments construed as the semantic entities that are the outcome of processes of reasoning, we outline and clarify our view that an argument is a proposition that represents a fact as both conveying some other fact and as doing so wholly. Further, we outline our view that, with respect to (...) arguments that are propositions, (roughly) two arguments are of the same type if and only if they represent the same relation of conveyance and do so in the same way. We then argue for our conceptions of arguments and argument types, and compare them to alternative positions. We also illustrate the need for, and some of the strengths of, our approach to classifying arguments through an examination of aspects of two prominent and recent attempts to classify arguments using argumentation schemes, namely those of M. Kienpointner and D. Walton. Finally, we clarify how our conception of arguments and of argument types can assist in developing an exhaustive classification of arguments. (shrink)

This volume presents mathematical game theory as an interface between logic and philosophy.

The importance of teaching critical thinking skills at the college level cannot be overemphasized. Teaching a subcategory of these skills—argument analysis—we believe is especially important for first-year students with their college careers, as well as their lives, ahead of them. The struggle, however, is how to effectively teach argument analysis skills that will serve students in a broad range of disciplines.

Douglas Walton’s multitudinous contributions to the study of argumentation seldom, if ever, directly engage with argumentation in mathematics. Nonetheless, several of the innovations with which he is most closely associated lend themselves to improving our understanding of mathematical arguments. I concentrate on two such innovations: dialogue types (§1) and argumentation schemes (§2). I argue that both devices are much more applicable to mathematical reasoning than may be commonly supposed.

The primary aim of this chapter is to explain the nature of evidential reasoning, the characteristic difficulties encountered, and the tools to address these difficulties. Our focus is on evidential reasoning in criminal cases. There is an extensive scholarly literature on these topics, and it is a secondary aim of the chapter to provide readers the means to find their way in historical and ongoing debates.

The Argument Web is maturing as both a platform built upon a synthesis of many contemporary theories of argumentation in philosophy and also as an ecosystem in which various applications and application components are contributed by different research groups around the world. It already hosts the largest publicly accessible corpora of argumentation and has the largest number of interoperable and cross compatible tools for the analysis, navigation and evaluation of arguments across a broad range of domains, languages and activity types. (...) Such interoperability is key in allowing innovative combinations of tool and data reuse that can further catalyse the development of the field of computational argumentation. The aim of this paper is to summarise the key foundations, the recent advances and the goals of the Argument Web, with a particular focus on demonstrating the relevance to, and roots in, philosophical argumentation theory. (shrink)

Argument invention is a method that can be used to help an arguer find arguments that could be used to prove a claim he needs to defend. The aim of this paper is to show how argumentation systems recently developed in artificial intelligence can be applied to the task of argument invention. One such system called Carneades is featured. Carneades can be used to analyze arguments, evaluate arguments, to make an argument diagram, and to construct arguments from a database. Using (...) some simple examples, the paper explains how Carneades works as a system of argument invention. (shrink)

How do Dutch people let each other know that they disagree? What do they say when they want to resolve their difference of opinion by way of an argumentative discussion? In what way do they convey that they are convinced by each other’s argumentation? How do they criticize each other’s argumentative moves? Which words and expressions do they use in these endeavors? By answering these questions this short essay provides a brief inventory of the language of argumentation in Dutch.

Attempts to use Toulmin's argument model in teaching argument have had mixed success. We suggest using it specifically to teach academic writing. Moreover, we think it should be used to teach what major constituents are characteristic of academic wri ting, rather than how to make each individual point. For example, one important feature of academic writing is that the writer should carefully discuss the warrant for the data she uses, whereas debaters in practical argument are rarely required to do so. (...) Extensive experience from the teaching of academic writing along these lines will be drawn upon. (shrink)

Although contemporary dialectical logic recognizes an important role for the opponent in argumentation, it remains loyal to the idea that arguments are supportive. In this paper, it is argued that because of this dialectical logic does not take seriously its own dialogical perspective. Without acknowledging a substantial role for rebutting factors in argumentation, the role of the opponent remains secondary. Toulmin’s understanding of the rebuttal suggests a way to incorporate such a substantial role of the opponent.

This paper is an exercise in intellectual history, an attempt to understand how a specific term—”informal logic”— came to be interpreted in so many different ways. I trace the emergence and development of “informal logic” to help explain the many different meanings, how they emerged and how they are related. This paper is also, to some degree, an account of a movement that developed outside the mainstream of philosophy, whose origins lie in a desire to make logic useful (echoing Dewey).

I take 'informal logic' to be the (descriptive and normative) study of 'real arguments'-arguments which are or have been used with the aim of convincing others of a point of view. I argue that the informal logic tradition thus conceived (i) lends strong support to something like Quine's view that our beliefs really support one another like the filaments in a spider's web--and thus that the traditional view that implication is an asymmetric relation is false; (ii) suggests that the classic (...) division of arguments into deductive and inductive has distorted our thinking about the evaluation of real arguments; and (iii) implies that naturalised epistemology is on the right track. (shrink)

Although debate is a richly structured and prevalent form of discourse, it has received little scholarly attention. Logicians have focused on the structure of individual arguments—how they divide into premises and conclusions, which in turn divide into various constituents. In contrast, I focus on the structure of sets of arguments, showing how arguments are themselves constituents in high-level dialectical structures. I represent debates and positions by graphs whose vertices correspond to arguments and whose edges correspond to two inter-argument relations: “dispute” (...) and “support,” respectively. On this basis I develop a theory of the structure of debate. (shrink)

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)

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)

The Toulmin diagram layout is very familiar and widely used, particularly in the teaching of critical thinking skills. The conventional box-and-arrow diagram is equally familiar and widespread. Translation between the two throws up a number of interesting challenges. Some of these challenges represent slightly different ways of looking at old and deep theoretical questions. Others are diagrammatic versions of questions that have already been addressed in artificial intelligence models of argument. But there are further questions that are posed as a (...) specific result of examining the diagram inter-translation problem. These three classes of problems are discussed. To the first class are addressed solutions based on engineering pragmatism; to the second class are addressed solutions drawn from the appropriate literature; and to the third class, fuller exploration is offered justifying the approaches taken in developing solutions that offer both pragmatic utility and theoretical interest. Finally, these solutions are explored briefly in the context of the Araucaria system, showing the ways in which analysts can tackle arguments either using one diagrammatic style or another, or even a combination of the two. (shrink)

David Hitchcock, in his recent “Informal Logic and the Concept of Argument”, defends a recursive definition of ‘argument.’ I present and discuss several problems that arise for his definition. I argue that refining Hitchcock’s definition in order to resolve these problems reveals a crucial, but minimally explicated, relation that was, at best, playing an obscured role in the original definition or, at worst, completely absent from the original definition.

Even with Kientpointer's and Walton's valuable work, we do not yet have a complete theory of argument schemes. A complete theory of argument schemes should contain at least the following: its theoretical motivation, the denotation of "argument" or "ar gumentation" used in the theory, an analysis of the concept of an argument scheme, a theory of classification of argument schemes, a solution to the problem of identifying which scheme is correct, and an account of the grounds of the normativity or (...) normat ive argument schemes. The paper will supply these elements, worked out as fully as space permits. (shrink)

Chapter 2 of Mill’s On Liberty is reconstructed as a complex argument for freedom of discussion; it consists of three subarguments, each possessing illative and dialectical components. The illative component is this: freedom of discussion is desirable because it enables us to determine whether an opinion is true, whereas its denial amounts to an assumption of infallibility; it improves our understanding and appreciation of the supporting reasons of true opinions, and our understanding and appreciation of their practical or emotional meaning; (...) it enables us to understand and appreciate every side of the truth, given that opinions tend to be partly true and partly false and people tend to be one-sided. The dialectical component consists of replies to ten objections, five in the first subargument, three in the second, one in the third, and one general. An analysis of Mill’s argument suggests that it is a contribution to argumentation theory; it advocates and practices a dialectical approach; its reconstruction and analysis are a contribution to argumentation theory; and it raises in a striking manner the issue of the relationship between epistemology and argumentation theory. (shrink)

This paper examines the views of Fogelin, Woods, Johnstone, etc., concerning deep disa-greements, force-five standoffs, philosophical controversies, etc. My approach is to reconstruct their views and critiques of them as meta-arguments, and to elaborate the meta-argumentative aspects of radical disa-greements. It turns out that deep disagreements are resolvable to a greater degree than usually thought, but only by using special principles and practices, such as meta-argumentation, ad hominem argumentation, Ramsey’s principle, etc.

Given a sort of trade-off between normative and descriptive analyses of argumentation, theorists have chosen either the perspective of the evaluating observer or that of the participant-like "co-interpreter" of argumentation. However, the evaluational perspective neglects the dialogical, self-organizing nature of arguing, whereas the participant perspective fails to capture the normative goal-directedness of persuasion and conflict resolution. Since arguers are both participants in argumentation as w ell as well as observers of it, I will propose a method, based on normative pragmatics, (...) of combining both perspectives. (shrink)

In this paper, a case study is conducted to test the capability of the Carneades Argumentation System to model the argumentation in a case where forensic evidence was collected in an investigation triggered by a conflict among art experts on the attribution of a painting to Leonardo da Vinci. A claim that a portrait of a young woman in a Renaissance dress could be attributed to da Vinci was initially dismissed by art experts. Forensic investigations were carried out, and evidence (...) was collected by art history experts and scientific experts. The expert opinions were initially in conflict, but new evidence shifted the burden of proof onto the side of the skeptics. This paper presents an analysis of the structure of the interlocking argumentation in the case using argument mapping tools to track the accumulation of evidence pro and con. (shrink)

Used informally, the Reductio ad Absurdum (RAA) consists in reasoning appealing to the logically implied, absurd consequences of a hypothetical proposition, in order to refute it. This kind of reasoning resembles the Argument from Consequences, which appeals to causally induced consequences. These types of argument are sometimes confused, since it is not worked out how these different kinds of consequences should be distinguished. In this article it is argued that the logical consequences in RAA-argumentation can take different appearances and that (...) it therefore must be concluded that RAA cannot be characterised by a specific content, but must instead be characterised as an argument form. Furthermore, clues are provided to distinguish RAA reasoning from the Argument from Consequences. (shrink)

This work discusses an empirical study of reasoning as it occurs in conversations. Reasoning in this context has features not usually accounted for in standard methods for describing argumentation (e.g., Toulmin, (1964), Toulmin, Rieke, and Janik (1984)). For example, insufficient attention has been paid to challenges which can be used to shift the ground of an argument and to the development of multiple conversational grounds. Moreover, even though the value of cooperative efforts in building arguments is widely recognized, more needs (...) to be said about analyzing co-constructed arguments. This empirical work was primarily descriptive and concerned with how people construct arguments in conversations, but one goal of the study was to lay groundwork for comparing the quality of reasoning in conversations which differ with respect to whether the arguments they contain are primarily the contributions of individuals or are genuinely co-constructed arguments. (shrink)

An approach to argument macrostructure -- The dialectical nature of argument -- Toulmin's problematic notion of warrant -- The linked-convergent distinction, a first approximation -- Argument structure and disciplinary perspective : the linked-convergent versus multiple-co-ordinatively compound distinctions -- The linked-convergent distinction, refining the criterion -- Argument structure and enthymemes -- From analysis to evaluation.

In this paper, we look at reasoning with evidence and facts in criminal cases. We show how this reasoning may be analysed in a dialectical way by means of critical questions that point to typical sources of doubt. We discuss critical questions about the evidential arguments adduced, about the narrative accounts of the facts considered, and about the way in which the arguments and narratives are connected in an analysis. Our treatment shows how two different types of knowledge, represented as (...) schemes, play a role in reasoning with evidence: argumentation schemes and story schemes. (shrink)

This paper attempts to systematically characterize critical reactions in argumentative discourse, such as objections, critical questions, rebuttals, refutations, counterarguments, and fallacy charges, in order to contribute to the dialogical approach to argumentation. We shall make use of four parameters to characterize distinct types of critical reaction. First, a critical reaction has a focus, for example on the standpoint, or on another part of an argument. Second, critical reactions appeal to some kind of norm, argumentative or other. Third, they each have (...) a particular illocutionary force, which may include that of giving strategic advice to the other. Fourth, a critical reaction occurs at a particular level of dialogue (the ground level or some meta-level). The concepts here developed shall be applied to discussions of critical reactions by Aristotle and by some contemporary authors. (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.

How to model relevance in argumentation is an important problem for informal logic. Dialectical relcvance is determined by the use of an argument for some purpose in different types of dialogue, according to the ncw dialectic. A central type of dialogue is persuasion dialogue in which one participant uses rational argumentation to try to get the other participant to accept a designated proposition. In this paper, a method for judging relevance in persuasion dialogue is presented. The method is based on (...) using the technique of argument diagramming. (shrink)

The paper considers the role of modality in the rational reconstruction of standpoints and arguments. The paper examines in what conditions modal markers can act as argumentative indicators and what kind of cues they provide for the reconstruction of argument. The paper critically re-examines Toulmin’s hypothesis that the meaning of the modals can be analyzed in terms of a field-invariant argumentative force and field-dependent criteria in the light of the Theory of Relative Modality developed within linguistic semantics, showing how this (...) theory can provide a more adequate model for exploiting the modals as indicators. The resulting picture confirms Toulmin’s intuition only in part: on the one hand the modals are always relational in nature and dependent on a contextual conversational background of propositions; on the other hand only epistemic-doxastic modals directly express a speech-act level inferential relation between a set of premises and a standpoint. Other modalities express relations (e.g. causal or final relations) better seen as part of the content of the argument whose argumentative relevance depends on the argumentation scheme employed. Thus non-epistemic modals function as argumentative indicators only indirectly. (shrink)