In this paper it is shown how tools developed in argumentation theory and artificial intelligence can be applied to the development of a new dialectical analysis of the speech act of making a proposal in a deliberation dialogue. These tools are developed, modified and used to formulate dialogue pre-conditions, defining conditions and post-conditions for the speech act of making a proposal in a deliberation dialogue. The defining conditions set out what is required for a move in a dialogue to count (...) as the making of a proposal by one of the parties. What is required are the conditions that (1) the move fit the requirements of the argumentation scheme for practical reasoning, and (2) the premises are propositions describing common goals of both parties or propositions that they reasonably consider means to achieve these goals. The analysis goes beyond the standard speech act approach by specifying not only the normative requirements for making a well-formed proposal, but also the requirements for responding to it by questioning or criticizing it, and the requirements for defending it. (shrink)

Although the last decade has seen a proliferation of ontological approaches to arguments, many of them employ ad hoc solutions to representing arguments, lack interoperability with other ontologies, or cover arguments only as part of a broader approach to evidence. To provide a better ontological representation of arguments, we present the Arguments Ontology (ArgO), a small ontology for arguments that is designed to be imported and easily extended by researchers who work in different upper-level ontology frameworks, different logics, and different (...) approaches to argument evaluation. Unlike most ontological approaches to arguments, ArgO utilizes Basic Formal Ontology (BFO) as an upper-level ontology, and may be used alongside other commonly used ontologies in the BFO framework, including boththe Information Artifact Ontology (IAO), and the Information Entity Ontology (INFO). Critically, our proposal is principled, based on rigorous definitions and formal axioms out of which characterizations of arguments naturally fall. It is our hope that ArgO may assist researchers in many projects, including: integrating heterogeneous sources of evidence, structuring the content of semantic wikis, and enhancing semantic reasoning. (shrink)

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. (shrink)

En este trabajo proponemos un análisis de los esquemas de argumento por signo que fueron identificados en las etiquetas interpretativas de las exposiciones permanentes de los museos de la región de la Araucanía. Se analizan cualitativa y críticamente tres casos de los veintiún esquemas por signo identificados. Las herramientas teóricas esgrimidas proceden de la pragma-dialéctica y la lógica informal. Nuestro objetivo es caracterizar los esquemas por signo identificados en las etiquetas de las exhibiciones de los museos de la Araucanía, en (...) la búsqueda de orientar su manejo en el diseño de exhibiciones museísticas significativas. Para ello, hemos desarrollado una matriz metodológica que adopta el levantamiento de una estructura argumental. Así, fue posible identificar los puntos de vista como las razones que lo justifican, además de identificar los esquemas argumentativos, a los cuales se les ha aplicado sus respectivas preguntas críticas. El análisis nos permitió concluir que en el empleo del esquema por signo siempre es necesario apoyarse en el entorno cercano donde se maneja el argumento, esto incluye la noción de lugar o de territorio en sus distintos niveles de significación. Asimismo, se ha comprobado como fundamental la incorporación de la tercera pregunta crítica al esquema por signo, la cual hace referencia al contexto donde se presenta el argumento. Por último, se ha detectado que los esquemas considerados complejos también realizan una referencia al lugar, pero con la utilización y combinación de variadas figuras retóricas, como la resignificación o sustitución. (shrink)

In this paper we describe the impact that Walton’s conception of argumentation schemes had on AI and Law research. We will discuss developments in argumentation in AI and Law before Walton’s schemes became known in that community, and the issues that were current in that work. We will then show how Walton’s schemes provided a means of addressing all of those issues, and so supplied a unifying perspective from which to view argumentation in AI and Law.

Christian Kock’s essays show the essential interconnectedness of practical reasoning, rhetoric and deliberative democracy. They constitute a unique contribution to argumentation theory that draws on – and criticizes – the work of philosophers, rhetoricians, political scientists and other argumentation theorists. It puts rhetoric in the service of modern democracies by drawing attention to the obligations of politicians to articulate arguments and objections that citizens can weigh against each other in their deliberations about possible courses of action.

According to Douglas Walton, the concept of presumption relates to both logical and dialogical components. Logically, a presumption is the conclusion of a presumptive defeasible inference. Dialogically, the function of a presumptions to shift the burden of proof to the respondent in order to move the dialogue forward when the proponent, due to an objective lack of evidence, cannot present a sufficiently persuasive proposition. Presumptive status, assigned only at the argumentation stage of dialogue, is provisional: a particular presumption stands until (...) further counter-indications are found. This paper points out some possible difficulties pertaining to Walton’s dialogical model of presumption. Firstly, once a presumption's typical practical function is made precise, Walton’s idea of presumption starts to lose its conceptual cohesion, thereby becoming applicable in the opening stage of dialogue, as well. Secondly, cohesion is lost also in practical contexts, since Walton's "seat belts" example might indicate that presumptions are not evidentially defeasible if the practical stakes are raised high enough. Most importantly, contextual evaluation may reveal that presumptions do not shift the burden of proof in any specific or genuine way. (shrink)

Standards and norms for reasoning function, in part, to manage epistemic risk. Properly used, modal qualifiers like presumably have a role in systematically managing epistemic risk by flagging and tracking type-specific epistemic merits and risks of the claims they modify. Yet, argumentation-theoretic accounts of presumption often define it in terms of modalities of other kinds, thereby failing to recognize the unique risk profile of each. This paper offers a stipulative account of presumption, inspired by Ullmann-Margalit, as an inferentially generated modal (...) qualifier, “presumably, p,” distinguishing it from other, particularly epistemic modalities, e.g., standing commitments, assumptions, assertions, suppositions, hypotheses, and defeasible claims. By avoiding the tranching of inferential instruments of qualitatively different bona fides and risk profiles, this account provides a more accurate risk-rating system that better manages epistemic risk in inference, as well as contributing to the normative theory of the operation of presumption in reasoning and argument. (shrink)

I will analyze the role of ostension in argumentation. Ostension involves gestures, bearing, postures, facial expressions, etc.; thus it can be argued that ostension can introduce non-verbal modes of argument, giving rise to multimodal arguments. Acts of ostension can be considered as a kind of speech acts according to the account in Wittgenstein’s Philosophical Investigations §27. As such they can provide the premises of a certain sort of arguments. We have to distinguish the proper act of ostension from both its (...) content and the object of ostension. While the latter can serve as evidence, as support for a linguistic claim without being part of it, as Dove points out, the act of ostension is a genuine act of arguing since to argue is to present something as a reason for something else. Acts of ostension are not assertive but directive acts, and so their content is not a statement but what I call an imperative. Thus I contend that imperatives can act as premises in some kind of arguments. Finally I will discuss whether arguments by ostension may be taken to be a kind of multimodal arguments. (shrink)

In many contexts a retraction of commitment isfrowned upon. For instance, it is not appreciated,generally, if one withdraws a promise or denies anearlier statement. Critical discussion, too, caneasily be disrupted by retractions, if these occur toofrequently and at critical points. But on the otherhand, the very goal of critical discussion –resolution of a dispute – involves a retraction,either of doubt, or of some expressed point of view.A person who never retracts, not even under pressureof cogent arguments, would hardly qualify as (...) areasonable discussant. Also, inconsistencies in one'sposition, once they have been pointed out, must bedealt with by some kind of retraction. The problem ofretraction is to find a suitable model of dialoguethat allows retractions where they seem reasonable, oreven required, and rules them out (or puts sanctionsupon them) whenever they would become disruptive of awell-organized process of dialogue.The present paper tries to point to a solution basedon the following principles: (1) Retraction rulesdetermine what retractions are permissible, and (2) ifpermissible what the consequences of retraction are.(3) Retraction rules vary according to the type ofdialogue and (4) according to the type of commitmentretracted. For instance, assertions and mereconcessions need to be distinguished, as well aslight-side and dark-side commitments. (5) To accountfor our contradictory intuitions on the issue ofretractions, one may best resort to a complex type ofdialogue in which different retraction rules hold fordifferent parts.The paper explains, summarizes, and expands upon thediscussion of retraction in Commitment inDialogue by Douglas Walton and the present author(cf. Walton and Krabbe 1995). (shrink)

In this paper, it is argued that the most fruitful approach to developing normative models of argument quality is one that combines the argumentation scheme approach with Bayesian argumentation. Three sample argumentation schemes from the literature are discussed: the argument from sign, the argument from expert opinion, and the appeal to popular opinion. Limitations of the scheme-based treatment of these argument forms are identified and it is shown how a Bayesian perspective may help to overcome these. At the same time, (...) the contributions of the standard scheme-based approach are highlighted, and it is argued that only a combination of the insights of different traditions will yield a complete normative theory of argument quality. (shrink)

This paper provides an analysis of the argument from cause and effect and a comparison of its various types with the argument from correlation. It will be claimed that arguments from causality and from correlation should be treated as equivalent for argumentative purposes. The main advantages of this approach as well as possible theo-retical objections will be discussed.

This paper is concerned with the deconstruction of defeasible argument schemes. It will be claimed that one of the central elements of all defeasible argument schemes is the rule of similarity which demands that one must ascribe similar propositions to essentially similar entities in order to be treated as reasonable. This rule is presented as interculturally valid and of such central importance that it could even been used as a defining quality of defeasible argumentation.

Metaphorical meaning can be analyzed as triggered by an apparent communicative breach, an incongruity that leads to a default of the presumptive interpretation of a vehicle. This breach can be solved through contextual renegotiations of meaning guided by the communicative intention, or rather the presumed purpose of the metaphorical utterance. This paper addresses the problem of analyzing the complex process of reasoning underlying the reconstruction of metaphorical meaning. This process will be described as a type of abductive argument, aimed at (...) explaining how the vehicle can best contribute to the purpose of the utterance. This type of reasoning involves the analysis of the possible predicates that can be and usually are attributed to the vehicle, and the selection of the one that can support the implicit conclusion constituting the communicative goal of the metaphorical utterance. Metaphorical meaning, in this perspective, becomes the outcome of a complex process of meaning reconstruction aimed at providing the best explanation of the function of the vehicle within a discourse move. (shrink)

Do not define argument by its use to persuade. for other uses of arguments exist. An argument is a proposition and a reason for it. and argumentation is an interchange involving two or more parties resulting in the assertion of one or more arguments coupled with anticipated or actual critical responses. A logically good argument has grounds adeq uate for the purposes at hand (true, probable, plausible, acceptable to the audience) and the grounds provide adequate support for the conclusion. The (...) norms for good logic in arguments are different from the norms for the good use of arguments. (shrink)

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)

This article concerns the structure of defeasible arguments like: 'If Bob has red spots, Bob has the measles; Bob has red spots; therefore Bob has the measles.' The issue is whether such arguments have the form of modus ponens or not. Either way there is a problem. If they don't have the form of modus ponens, the common opinion to the contrary taught in leading logic textbooks is wrong. But if they do have the form of modus ponens, doubts are (...) raised about the conventional dogma that all arguments having the form of modus ponens are deductively valid. By carefully examining arguments on both sides of the issue, reasonable doubts are raised about the view that all arguments having a modus ponens form are valid. (shrink)

Designing security measures often involves trade-offs between various types of objectives. Multiple stakeholders may have conflicting demands and may have different ideas on how to resolve the resulting design conflicts. This paper reports on an application of value-sensitive design. Based on argumentation theory and social values, the paper develops a structured approach for discussing design conflicts, called value-based argumentation. The application domain examined in the paper is concerned with physical safety and security issues that arise in cross-border shipments. We first (...) identify the kinds of dialogues that take place in this domain, in particular, audit dialogues to determine whether security measures comply with regulations. Based on argumentation theory we develop a formal language and a diagramming approach intended to facilitate parties in identifying, discussing and reaching agreement about security risks and corresponding mitigation measures. Trade-offs can be dealt with by making underlying values explicit. Using a stylized example, the approach was successfully taught to practitioners working with EU customs regulations. Practitioners generally found the approach helpful, in particular to bring out implicit underlying motivations. We conclude by discussing how our approach can be generalized to other kinds of dialogues involving design conflicts. (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)

Trudy Govier argues in The Philosophy of Argument that adversariality in argumentation can be kept to a necessary minimum. On her ac-count, politeness can limit the ancillary adversariality of hostile culture but a degree of logical opposition will remain part of argumentation, and perhaps all reasoning. Argumentation cannot be purified by politeness in the way she hopes, nor does reasoning even in the discursive context of argumentation demand opposition. Such hopes assume an idealized politeness free from gender, and reasoners with (...) inhuman or at least highly privileged capabilities and no need to learn from others or share understanding. (shrink)

In this paper, I argue that arguments from expert opinion, i.e., inferences from “Expert E says that p” to “p,” where the truth value of p is unknown, are weak arguments. A weak argument is an argument in which the premises, even if true, provide weak support—or no support at all—for the conclusion. Such arguments from expert opinion are weak arguments unless the fact that an expert says that p makes p significantly more likely to be true. However, research on (...) expertise shows that expert opinions are only slightly more accurate than chance and much less accurate than decision procedures. If this is correct, then it follows that arguments from expert opinion are weak arguments. (shrink)

Whorf and Wittgenstein are perhaps the most famous names in linguistics and philosophy associated with the assumption that language plays a decisive role in shaping our view of reality. After a critical discussion of Whorf's linguistic relativity principle I conclude that it is not language as a system, but the use of language according to the rules of language games which connects language thought and world view, especially if some particular usage becomes the commonly accepted norm. This traditional norm also (...) enters argumentative discourse in the form of background assumptions occuring in the premises of arguments. Thus, traditional points of view and prevailing ideologies in a society, even if challenged in discussions, can become reinforced and stabilized. This is illustrated with a critical analysis of the role and function of tautological utterances in argumentative discourse, which only apparently are compelling means of argumentation. (shrink)

This project tackles the problem of analyzing a specific form of reasoning called ‘sunk costs’ in economics and ‘argument from waste’ in argumentation theory. The project is to build a normative structure representing the form of the argument, and then to apply this normative structure to actual cases in which the sunk costs argument has been used. The method is partly structural and partly empirical. The empirical part is carried out through the analysis of case studies of the sunk costs (...) argument found in business decision-making, as well as other areas like medical decision-making and everyday conversational argumentation. The structural part is carried out by using existing methods and techniques from argumentation theory, like argumentation schemes. The project has three especially significant findings. First, the sunk costs argument is not always fallacious, and in many cases it can be seen to be a rational precommitment strategy. Second, a formal model of argumentation, called practical reasoning, can be constructed that helps a rational critic to judge which sunk costs arguments are fallacious and which are not. Third, this formal model represents an alternative model of rationality to the cost-benefit model based on Bayesian calculation of probabilities. This alternative model is called the argumentation model, and it is based on interpersonal reasoning in dialogue as the model of rational thinking. This model in turn is based on the underlying notion of commitment in dialogue. (shrink)

We commonly think of presumptions as second-best inferential tools allowing us to reach conclusions, if we must, under conditions of limited information. Scholarship on the topic across the disciplines has espoused a common conception of presumptions that defines them according to their function within the decisionmaking process. This focus on the “private” face of presumptions has generated a predominantly critical and grudging view of them, perpetuated certain conceptual ambiguities, and, most important, neglected the fact that what we refer to as (...) “presumptions” have distinguishing features other than the defeasibility and burden-shifting effects associated with their use as inferential tools. When a decisionmaker gives reasons for a conclusion, the decisionmaker often cites a presumption among the reasons for that conclusion; in this guise – their “public” face – presumptions display different, and uniquely valuable, features that remain hidden if we understand them only as aids to inference. This essay both surveys recent approaches to the critical analysis of presumptions in law, philosophy, and discourse studies, and offers an account of how we might begin to think about this other, public face of presumptions. (shrink)

While there has been in depth discussion of many particular argumentation schemes, some lament that there is little to no theory underpinning the notion of an argumentation scheme. Here I shall argue against the utility of argument schemes, at least as a fundamental part of a complete theory of arguments. I shall also present and defend a minimalist theory of their nature—a scheme is just a set of proposition expressions and propositional functions. While simple, the theory contravenes several typical desiderata (...) of argumentation schemes such as aiding in the identification of enthymemes and keeping arguments constrained to a manageable taxonomy. So much the worse for the desiderata. Instead, I shall recommend focusing less on schemes and more on the component propositional functions. (shrink)

I explore how empathetic visual argument may be the mode best suited for eliciting appropriate force to the reasons given by arguers who face systematic identity prejudices. In the verbal mode, this force is often skewed through epistemic injustice, argumentative injustice, and discursive injustice. Highlighting their reliance on the Aristotelian sense of enthymeme, I show how visual arguments are highly context specific. Using Ian Dove’s Visual Scheming and the theory of the Retort collective via case study, I demonstrate how the (...) visual mode can leave the appropriate force in the arguer’s control. (shrink)

Článek se věnuje argumentu kluzkého svahu a otázce, jak jej identifikovat a hodnotit. Argument kluzkého svahu je využíván v rámci praktického uvažování a v dialogu, svou strukturou odpovídá negativnímu argumentu z důsledku, má v zásadě defeasibilní povahu a je často účinný při snaze přenést důkazní břemeno na stranu oponenta. Hodnocení argumentu kluzkého svahu je založeno na kontextu dialogu spíše než na hodnocení jeho deduktivní či induktivní správnosti.V příspěvku jsou představeny čtyři typy argumentu. Zaprvé argument kluzkého svahu typu sorites, jehož označení (...) odkazuje k paradoxu sorites neboli paradoxu hromady. Argument kluzkého svahu typu sorites je ve své podstatě kombinací argumentu ad absurdum a sofismatu polyzeteseos. Zadruhé kauzální argument kluzkého svahu, který se zakládá na předpovědi série událostí. Tento typ argumentu je často označován jako teorie domina či dominový efekt. Nicméně, ať už jej pojmenujeme jakkoli, zásadní pro jeho identifikaci, analýzu a hodnocení je fakt, že se jedná o předpověď budoucího stavu věcí. Předpověď více či méně pravděpodobnou, zakládající se na slabých či silných předpokladech. Zatřetí precedentální argument kluzkého svahu, který se objevuje v diskuzích o možnosti změny současného pravidla či platné normy. Argumenty založené na precedentu obecně souvisí s usuzováním na základě konkrétního případu. Precedentální argument kluzkého svahu využívá podobnosti mezi případy, a je tedy založen na analogii. A posledním, čtvrtým typem argumentu kluzkého svahu, kterému se příspěvek věnuje, je tzv. plný argument kluzkého svahu či kombinovaný argument kluzkého svahu. (shrink)

Many of the methods commonly used to research mathematical practice, such as analyses of historical episodes or individual cases, are particularly well-suited to generating causal hypotheses, but less well-suited to testing causal hypotheses. In this paper we reflect on the contribution that the so-called hypothetico-deductive method, with a particular focus on experimental studies, can make to our understanding of mathematical practice. By way of illustration, we report an experiment that investigated how mathematicians attribute aesthetic properties to mathematical proofs. We demonstrate (...) that perceptions of the aesthetic properties of mathematical proofs are, in some cases at least, subject to social influence. Specifically, we show that mathematicians’ aesthetic judgements tend to conform to the judgements made by others. Pedagogical implications are discussed. (shrink)

I argue for the distinction between presuming that p and maintaining that presumably p. In order to make sense of this distinction, I defend a non-inferentialist conception of presumptions and offer an account of the correctness conditions for both presumptions and presumptive inferences. I characterize presumptions as a type of constative speech-act having certain semantic correctness conditions. In turn, regarding presumptive inferences, my strategy is to provide the correctness conditions for the use of an epistemic modal such as “presumably.” This (...) epistemic modal is characterized as a force indicator for speech-acts of concluding in complex speech-acts of arguing involving presumptive inferences. (shrink)

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. (shrink)

In academic contexts the appeal to authority is a quite common but seldom tested argument, either because we accept the authority without questioning it, or because we look for alternative experts or reasons to support a different point of view. But, by putting ourselves side by side an already accepted authority, we often rhetorically manoeuvre to displace the burden of the proof to avoid the fear to present our opinions and to allow face saving.

I will situate the fallacies approach to reasoning with the aim of making it more relevant to contemporary life and thus intellectually significant and valuable as a method for teaching reasoning. This entails a revision that will relegate some of the traditional fallacies to the realm of history and introduce more recently recognized problems in reasoning. Some newly recognized problems that demand attention are revealed by contemporary science studies, which reveal at least two tenacious problems in reasoning that I will (...) explore in this paper. One of these problems is androcentrism, a ubiquitous problem with reasoning that feminists exposed in the twentieth century but that continues to pervade people’s reasoning. The other is biological reductionism in at least two specific forms: genetic determinism and adaptationism. (shrink)

Primeiramente, oferecemos uma apresentação teórica da representação do pensamento prático, começando pela distinção entre silogismo dialético e silogismo demonstrativo. Fazemos referência à crítica de Toulmin contra o dedutivismo dominante de seu tempo. Em seguida, fornecemos argumentos para apoiar a relevância heurística do modelo de Toulmin para entender a discussão sobre a inclusão da lógica padrão na representação do pensamento comum. Afirmamos que o projeto analítico toulmaniano permite entender, com clareza metódica, a derrotabilidade dos argumentos do senso comum por meio da (...) investigação da noção modal de probabilidade na linguagem comum. First, we offer theoretical resemblance of the representation of practical reasoning, beginning with the distinction between demonstrative and dialectical syllogism. We make reference to the Toulmin’s critique against to the dominant deductivism in his time. Then we give arguments to sustain the heuristic relevance of Toulmin’s model to understand the discussion about the inclusion of default logics in the representation of ordinary reasoning. We assert that the Toulminian analytic design allows to understand, with methodical clarity, the defeasibility of common sense arguments by means of the investigation of the modal notion of probability in ordinary language. (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)

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)

This paper is divided in five sections. Section 11.1 sketches the history of the distinction between speech act with negative content and negated speech act, and gives a general dynamic interpretation for negated speech act. “Downdate semantics” for AGM contraction is introduced in Section 11.2. Relying on semantically interpreted contraction, Section 11.3 develops the dynamic semantics for constative and directive speech acts, and their external negations. The expressive completeness for the formal variants of natural language utterances, none of which is (...) a retraction, has been proved in Section 11.4. The last section gives a laconic answer to the question posed in the title of the paper. (shrink)

John Pollock (1940?2009) was an influential American philosopher who made important contributions to various fields, including epistemology and cognitive science. In the last 25 years of his life, he also contributed to the computational study of defeasible reasoning and practical cognition in artificial intelligence. He developed one of the first formal systems for argumentation-based inference and he put many issues on the research agenda that are still relevant for the argumentation community today. This paper presents an appreciation of Pollock's work (...) on defeasible reasoning and its relevance for the computational study of argument. In our opinion, Pollock deserves to be remembered as one of the founding fathers of the field of computational argument, while, moreover, his work contains important lessons for current research in this field, reminding us of the richness of its object of study. (shrink)

This paper presents an analysis of argumentation in direct-to-consumer health product ads in Newsweek that brings out special features of the arguments used in the ads, including practical reasoning, chained arguments, enthymemes, and prolepsis. A way to help overcome deficiencies in techniques of tailored health communication in consumer health informatics is shown by using argumentation schemes, argument visualisation tools, and dialogue models to frame these persuasive communication messages. The evidence collected is shown to be useful to allow the health informatics (...) communicator and the person to whom message was directed to interact in a dialogue format where arguments can be put forward by both parties in a way that responds to the previous arguments and questions of the other party. (shrink)

The research described here explores the idea of using Supreme Court oral arguments as pedagogical examples in first year classes to help students learn the role of hypothetical reasoning in law. The article presents examples of patterns of reasoning with hypotheticals in appellate legal argument and in the legal classroom and a process model of hypothetical reasoning that relates them to work in cognitive science and Artificial Intelligence. The process model describes the relationships between an advocate’s proposed test for deciding (...) a case or issue, the facts of the hypothetical and of the case to be decided, and the often conflicting legal principles and policies underlying the issue. The process model of hypothetical reasoning has been partially implemented in a computerized teaching environment, LARGO (“Legal ARgument Graph Observer”) that helps students identify, analyze, and reflect on episodes of hypothetical reasoning in oral argument transcripts. Using LARGO, students reconstruct examples of hypothetical reasoning in the oral arguments by representing them in simple diagrams that focus students on the proposed test, the hypothetical challenge to the test, and the responses to the challenge. The program analyzes the diagrams and provides feedback to help students complete the diagrams and reflect on the significance of the hypothetical reasoning in the argument. The article reports the results of experiments evaluating instruction of first year law students at the University of Pittsburgh using the LARGO program as applied to Supreme Court personal jurisdiction cases. The learning results so far have been mixed. Instruction with LARGO has been shown to help law student volunteers with lower LSAT scores learn skills and knowledge regarding hypothetical reasoning better than a text-based approach, but not when the students were required to participate. On the other hand, the diagrams students produce with LARGO have been shown to have some diagnostic value, distinguishing among law students on the basis of LSAT scores, posttest performance, and years in law school. This lends support to the underlying model of hypothetical argument and suggests using LARGO as a pedagogically diagnostic tool. (shrink)

In all three of its manifestations, —abusive, circumstantial and tu quoque—the role of the ad hominem is to raise a doubt about the opposite party’s casemaking bona-fides.Provided that it is both presumptive and provisional, drawing such a conclusion is not a logical mistake, hence not a fallacy on the traditional conception of it. More remarkable is the role of the ad hominem retort in seeking the reassurance of one’s opponent when, on the face of it, reassurance is precisely what he (...) would seem to be ill-placed to give. Brief concluding remarks are given over to an examination of rival approaches to the ad hominem, especially those in which it is conceived of as a dialectical error. (shrink)

This paper aims at comparing and relating belief revision and argumentation as approaches to model reasoning processes. Referring to some prominent literature references in both fields, we will discuss their (implicit or explicit) assumptions on the modeled processes and hence commonalities and differences in the forms of reasoning they are suitable to deal with. The intended contribution is on one hand assessing the (not fully explored yet) relationships between two lively research fields in the broad area of defeasible reasoning and (...) on the other hand pointing out open issues and potential directions for future research. (shrink)

There are many benefits of using argumentation-based techniques in multi-agent systems, as clearly shown in the literature. Such benefits come not only from the expressiveness that argumentation-based techniques bring to agent communication but also from the reasoning and decision-making capabilities under conditions of conflicting and uncertain information that argumentation enables for autonomous agents. When developing multi-agent applications in which argumentation will be used to improve agent communication and reasoning, argumentation schemes are useful in addressing the requirements of the application domain (...) in regards to argumentation. In this work, we propose an argumentation framework that takes into account the particular structure of argumentation schemes at its core. This paper formally defines such a framework and experimentally evaluates its implementation for both argumentation-based reasoning and dialogues. (shrink)

My purpose here is to describe a type of argument characterized by the fact that one of its premises is a directive—i.e. what is expressed by a directive sentence: a general instruction how to proceed or act. This directive premise brings an ostensive mechanism for the inclusion of visual or multimodal elements in an argument. If an argument is an invitation to inference, by using such a directive utterance the addresser is inviting the addressee to make an inference from an (...) image, not from a proposition. Hence I will call them arguments from ostension or from deixis. (shrink)