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.

In this paper it is shown how plausible reasoning of the kind illustrated in the ancient Greek example of the weak and strong man can be analyzed and evaluated using a procedure in which the pro evidence is weighed against the con evidence using formal, computational argumentation tools. It is shown by means of this famous example how plausible reasoning is based on an audience’s recognition of situations of a type they are familiar with as normal and comprehensible in their (...) shared common knowledge. The paper extends previous work on this example by using three new multiagent argumentation schemes closely related to the scheme for argument from negative consequences. (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)

. A heuristic search procedure for inventing legal arguments is built on two tools already widely in use in argumentation. Argumentation schemes are forms of argument representing premise‐conclusion and inference structures of common types of arguments. Schemes especially useful in law represent defeasible arguments, like argument from expert opinion. Argument diagramming is a visualization tool used to display a chain of connected arguments linked together. One such tool, Araucaria, available free at , helps a user display an argument on the (...) computer screen as an inverted tree structure with an ultimate conclusion as the root of the tree. These argumentation tools are applicable to analyzing a mass of evidence in a case at trial, in a manner already known in law using heuristic methods and Wigmore diagrams . In this paper it is shown how they can be automated and applied to the task of inventing legal arguments. One important application is to proof construction in trial preparation. (shrink)

Aristotle's conception and use of ta endoxa are key points to our understanding of Aristotelian dialectic. But, nowadays, they are not of historical or hermeneutic importance alone, as, in Aristotle's treatment of endoxa, we still see a relevant contribution to the modern study of argumentation. I propose here an interpretation of endoxa to that effect: namely, as plausible propositions. This version is not only defensible in the Aristotelian context, it may also shed new light on some of his assumptions and (...) methodological shortcomings – e.g. concerning the 'plausible/implausible' pair –; finally, it will even enable us to show certain basic hints and guidelines, advanced by Aristotle's study of endoxa, which still serve nowadays to orientate our studies of argumentation from the angle of a theory of plausible argument currently under construction. These hints and guidelines suggest a pragmatic, gradual and comparative discursive concept of plausibility, and point, in particular, towards the reasonable dealing with, and weighing up of, differences of opinion within this frame of reference. (shrink)

The study describes a method created for the analysis of persuasive strategies, called rhetorical heuristics, which can be applied in speeches where the argument focuses primarily on questions of fact. First, the author explains how the concept emerged from the study of classical oratory. Then the theoretical background of rhetorical heuristics is outlined through briefly discussing relevant aspects of the psychology of decision-making. Finally, an exposition of how one could find these persuasive strategies introduces rhetorical heuristics in more detail.

Although he does not provide a general analysis of argumentation, Aristotle is a highly influential source of modern argumentation theory. In his treatises the Topics, the Sophistical Refutations and the Rhetoric, Aristotle presents complementary aspects of a theory of sound arguments that are seen as the most effective means of persuasion. Aristotle’s central notion of a deductive argument (sullogismos) does not include references to an addressee, the situative context or non-verbal aspects of communication, and thus differs from some modern views (...) on argumentation. A deductive argument in the Aristotelian sense is a sequence of intellectual steps where the conclusion follows of necessity from the premises. Aristotle does not relativize or relax this notion but takes other factors into account by providing supplementary theoretical elements. For example, he reflects on acceptable premises (endoxa), the adjustment of rhetorical arguments to the horizon of the audience, methods of finding premises on the basis of argumentative schemes (topoi), the use of non-argumentative means of persuasion, and a framework of implicit discourse rules. Many of these themes are, albeit under a different name, still discussed in modern argumentation theory. (shrink)

Just as Aristotelian dialectic sharply distinguishes between real and fallacious arguments, Aristotelian rhetoric distinguishes between real and fallacious enthymemes. For this reason Aristotle’s Rhetoric includes a chapter – chapter II.24 – that is exclusively devoted to what Aristotle calls “topoi” of fallacious enthymemes. Thus, the purpose of this chapter seems to be equivalent to the purpose of the treatise Sophistici Elenchi, which attempts to give a complete list of all possible types of fallacious arguments. It turns out that, although the (...) Rhetoric’s list of fallacious types of rhetorical arguments basically resembles the list from the Sophistici Elenchi, there also are some striking differences. The paper tries to account for the relation between these two, more or less independent, Aristotelian approaches to the phenomenon of fallacious arguments. Can one of these two lists be seen as the basic or original one? And what is the point in deviating from this basic list? Are all deviations occasioned by the specific contexts of the rhetorical use on the one hand, and the dialectical on the other? Or do the two lists display different logical assumptions? Even an only tentative answer to this set of questions will help to clarify another but closely related scholarly problem, namely the relation between the Rhetoric’s list of topoi for real enthymemes and the Topics’ list of topoi for real dialectical arguments. It will also help to account for the general place of fallacious arguments within Aristotle’s dialectic-based approach the rhetoric. (shrink)

Inspired by Pierre-Jean-Georges Cabanis' claim in 1798 that physicians might learn forms of medical reasoning from les anciens rhéteurs, in this paper I explore intimate associations between medicine and rhetoric over the longue durée. Gravely susceptible to error, medical reasoning relies on signs and examples, both gleaned from experience and both the subject of rhetorical inquiry; like rhetoric, medicine reaches plausible conclusions from probable premises. Here, ranging from Hippocrates and Plato through Aristotle to early modern England, I argue that forms (...) of inference developed and refined in the history of rhetoric offer ancient and early modern philosophers and physicians models and metaphors for their own forays into the probable. (shrink)

Enthymemes are traditionally defined as arguments in which some elements are left unstated. It is an empirical fact that enthymemes are both enormously frequent and appropriately understood in everyday argumentation. Why is it so? We outline an answer that dispenses with the so called "principle of charity", which is the standard notion underlying most works on enthymemes. In contrast, we suggest that a different force drives enthymematic argumentation—namely, parsimony, i.e. the tendency to optimize resource consumption, in light of the agent's (...) goals. On this view, the frequent use of enthymemes does not indicate sub-optimal performance of arguers, requiring appeals to charity for their redemption. On the contrary, it is seen as a highly adaptive argumentation strategy, given the need of everyday reasoners to optimize their cognitive resources. Considerations of parsimony also affect enthymeme reconstruction, i.e. the process by which the interpreter makes sense of the speaker's enthymemes. Far from being driven by any pro-social cooperative instinct, interpretative efforts are aimed at extracting valuable information at reasonable costs from available sources. Thus, there is a tension between parsimony and charity, insofar as the former is a non-social constraint for self-regulation of one's behaviour, whereas the latter implies a pro-social attitude. We will argue that some versions of charity are untenable for enthymeme interpretation, while others are compatible with the view defended here, but still require parsimony to expose the ultimate reasons upon which a presumption of fair treatment in enthymeme reconstruction is founded. (shrink)

Deliberative or discursive models of democracy have recently enjoyed a revival in both political theory and policy practice. Against the picture of democracy as a procedure for aggregating and effectively meeting the given preference of individuals, deliberative theory offers a model of democracy as a forum through which judgements and preferences are formed and altered through reasoned dialogue between free and equal citizens. Much in the recent revival of deliberative democracy, especially that which comes through Habermas and Rawls, has Kantian (...) roots. Deliberative institutions are embodiments of the free public use of reason that Kant takes to define the enlightenment project. Within the Kantian model the public use of reason is incompatible with the use of rhetoric. While this paper rejects strong rhetorical criticisms of deliberative democracy which render all communication strategic, it argues that rhetorical studies of deliberation have highlighted features of deliberation which point to significant weaknesses in Kantian approaches to it. Two features are of particular importance: the role of testimony and judgements of credibility in deliberation; and the role of appeal to emotions in public discourse. Both from the Kantian perspective are potential sources of heteronomy. However, the appeal to testimony and emotion are features of public deliberation that cannot and should not be eliminated. For those committed to the enlightenment values that underlie the deliberative model of democracy the question is whether these rhetorical features of deliberation are incompatible with those values. The paper argues that they are compatible. It does so by defending an Aristotelian account of rhetoric in public deliberation which denies the Platonic contrast between reasoned discourse and rhetoric which the Kantian model inherits. (shrink)

This paper focuses on an explanation in a newspaper article: why new European Union citizens will come to the UK from Eastern Europe (e.g., because of available jobs). Using a corpus-based method of analysis, I show how regular target readers have been positioned to generate premises in dialogue with the explanation propositions, and thus into an understanding of the explanation as an argument, one which contains a biased conclusion not apparent in the text. Employing this method, and in particular ‘corpus (...) comparative statistical keywords’, I show how two issues can be freshly looked at: implicit premise recovery; the argument/explanation distinction. (shrink)

This article deals with the relationship between argumentation and persuasion. It defends the idea that these two concepts are not as opposed as all too often said. If it is important to recognize their differences (there are argumentative discourses without persuasion and persuasive discourses without argumentation), there is nevertheless an overlap, in which characteristics are taken from both. We propose to call this overlap “persuasive argumentation”. In order to bridge argumentation and persuasion, we will first distinguish the latter from manipulation. (...) In the second part of this article, we will analyze four cases of persuasive argumentation: the enthymeme, a few rhetorical figures, narration and visual argumentation. (shrink)

Stasis is a process of classical rhetoric that identifies the core issue in a trial or a similar debate. Hermagoras of Temnos included the first comprehensive analysis of stasis in his second-century BCE treatise on rhetoric, now lost. Modern scholars tend to echo George Kennedy, who maintains that Hermagoras’ inspiration for the hierarchical structure of stasis is indeterminate. This article, however, employs scholarship in legal semiotics, including the work of Miklós Könczöl and Bernard S. Jackson, to argue that Hermagoras based (...) stasiastic structure on Aristotle’s first-figure syllogism. Ideally, knowledge of that structure can enhance modern applications of stasis. (shrink)

In Roman rhetoric, contrarium was variably considered either a figure of speech or an argument. The paper examines the logical pattern of this type of argument, which according to Cicero is based on a third Stoic indemonstrable syllogism: $$ \neg ({\hbox{p}} \wedge {\hbox{q}});<$> <$>{\hbox{p}} \to \neg {\hbox{q}}{\hbox{.}} $$ The persuasiveness of this type of argument, however, vitally depends on the validity of the alleged ‹incompatibility’ forming its major premiss. Yet this appears to be the argument’s weak point, as the ‹incompatibilities’ (...) employed generally hold for the most part only, and are reducible to topical argument schemes. This is why in practical usage such arguments are most often phrased as rhetorical questions, the persuasive force of which, enhanced by certain strategical maneuverings and fallacies, makes the audience swallow the argument. (shrink)

In many actual arguments, the conclusion seems intuitively to follow from the premisses, even though we cannot show that it follows logically. The traditional approach to evaluating such arguments is to suppose that they have an unstated premiss whose explicit addition will produce an argument where the conclusion does follow logically. But there are good reasons for doubting that people so frequently leave the premisses of their arguments unstated. The inclination to suppose that they do stems from the belief that (...) the only way in which an argument's conclusion can follow definitely from its premisses is to follow logically. I argue that this belief is mistaken. I propose a revision of the current generic conception of logical consequence, and its variant specifications, to avoid the paradoxes of strict implication. The revised conception can then be naturally extended to include also what we might call 'enthymematic consequence'. This concept is a kind of consequence, whose properties merit investigation. (shrink)

The core sense of pistis as understood in Posterior Analytics, De Anima, and the Rhetoric is not that of a logical relation in which cognitively grasped propositions stand in respect to one another, but the result of an act of socially embedded interpersonal communication, a willing acceptance of guidance offered in respect to action. Even when pistis seems to have an exclusively epistemological sense, this focal meaning of pistis is implicit; to have pistis in a proposition is to willingly accept (...) that proposition as a basis for some kind of activity (albeit possibly theoretical) as a result of some kind of communicative act. This is in accordance with Aristotle’s understanding of argumentation as a social practice, entered into in order lead others to certain actions, for certain ends. Understanding pistis in this way allows us to understand how it is that pistis admits of quantitative variation. (shrink)

For several millennia now, the enthymeme has been taught, on the putative authority of Aristotle, as "a kind of syllogism" —that is, a rhetorical syllogism—that consists in a three-part unit of deductive reasoning that parallels the inductive reasoning of the example. The rhetorical syllogism is said to be imperfect or incomplete because it relies on probable or particular rather than certain or universal premises and because the speaker suppresses one premise or the conclusion, usually the major premise, leaving it with (...) only two stated terms as follows:Socrates is a manSocrates is mortalOne premise is left unstated because it is known to the members of the audience (they... (shrink)

In Sophistical Refutations 8 Aristotle claims that every sophistical refutation depends on a false belief which is implicitly held by the victim of the fallacy and can normally be elicited from him as an explicit additional premiss. In this case the fallacious argument will be turned into a valid one, albeit with a false premiss. The paper discusses the nature of the FVP and tries to discover how it works when it tacitly causes the false appearance of a fallacious argument.

Exploring informal components of clinical reasoning, we argue that they need to be understood via the analysis of professional wisdom. Wise decisions are needed where action or insight is vital, but neither everyday nor expert knowledge provides solutions. Wisdom combines experiential, intellectual, ethical, emotional and practical capacities; we contend that it is also more strongly social than is usually appreciated. But many accounts of reasoning specifically rule out such features as irrational. Seeking to illuminate how wisdom operates, we therefore build (...) on Aristotle’s work on informal reasoning. His account of rhetorical communication shows how non-formal components can play active parts in reasoning, retaining, or even enhancing its reasonableness. We extend this account, applying it to forms of healthcare-related reasoning which are characterised by the need for wise decision-making. We then go on to explore some of what clinical wise reasoning may mean, concluding with a case taken from psychotherapeutic practice. (shrink)

When in classical formal logic the notions of deduction, valid inference and logical consequence are defined, causal language plays no role. The founder of western logic, Aristotle, identified ‘non-cause’, or ‘positing as cause what is not a cause’, as a logical fallacy. I argue that a systematic re-examination of Aristotle's analysis of NCF, and the related language of logical causality, in the Sophistical Refutations, Topics, Analytics and Rhetoric, helps us to understand his conception of. It reveals that Aristotle's syllogismhood is (...) non-monotonic, and thus narrower than classical validity as consisting in, or coextensive with, necessary truth-preservation. It also supports the conclusion that a syllogism is a form of relevant consequence: the premisses must be causes of the conclusion in the sense that they are not only sufficient but also necessary for the conclusion to follow. Close analysis of NCF also suggests that syllogistic relevance is not a semantic matter, but a syntactic.. (shrink)

Which properties are characteristic of the enthymeme in Aristotle's Rhetoric? There is no consensus on this point. The present discussion centres on three properties. 1. Is there always an implicit premise? (Answer: Above all, a pragmatic level and a logical level must be distinguished.) 2. Do the premises consist by definition of probabilities and signs? (Answer: No.). 3. Are all enthymemes reducible to a syllogistic form? (Answer: The literature pertaining to this question is dominated by a false dilemma: an enthymeme (...) does not have either a topical or a syllogistic structure). In general, Aristotle's approach to the enthymeme in the Rhetoric appears to shift from argumentation theory to logic. (shrink)

The ways in which the Aristotelian sciences are related to each other has been discussed in the literature, with some focus on the subalternate sciences. While it is acknowledged that Aristotle, and Plato as well, was concerned as well with how the arts were related to one another, less attention has been paid to Aristotle's views on relationships among the arts. In this paper, I argue that Aristotle's account of the subalternate sciences helps shed light on how Aristotle saw the (...) art of rhetoric relating to dialectic and politics. Initial motivation for comparing rhetoric with the subalternate sciences is Aristotle's use of the language of boundary transgression, germane to the Posterior Analytics, when discussing rhetoric’s boundaries, as well as the language of "over" and "under" found in APo. First, I discuss three passages in Rhetoric Book I and argue that Garver's (1988) account cannot be correct. Second, I look to the subalternate sciences, especially focusing on optics and the distinction between "unqualified" optics and mathematical optics. Third, I discuss rhetoric's dependence on both dialectic and politics. (shrink)

This paper argues for a reinterpretation of Aristotle's concept of an enthymeme and also his wider informal logic in terms of arguments that are defeasible. They are represented by forms of argument that are called argumentation schemes, considered to be similar to forms of argument found in deductive logic, but different from the foregoing in virtue of their being defeasible. Indeed, the most interesting schemes have been put forward as a helpful way of characterizing structures of human reasoning that have (...) proved troublesome to model deductively. The paper sheds new light on Aristotle's topics and how to dene `enthymeme'. If the traditional denition of an enthymeme in logic accepted for over two thousand years is a misnomer, the question is raised whether we ought to redene it as a defeasible argumentations scheme or leave things as they are. (shrink)

The article develops and justifies, on the basis of the epistemological argumentation theory, two central pieces of the theory of evaluative argumentation interpretation: 1. criteria for recognizing argument types and 2. rules for adding reasons to create ideal arguments. Ad 1: The criteria for identifying argument types are a selection of essential elements from the definitions of the respective argument types. Ad 2: After presenting the general principles for adding reasons (benevolence, authenticity, immanence, optimization), heuristics are proposed for finding missing (...) reasons, for deductive arguments, e.g., semantic tableaux are suggested. (shrink)

This dissertation explores how antiquity and some of its early modern admirers understand the notion of certainty, especially as it is theorized in Quintilian's Institutio Oratoria, a first-century educational manual for the aspiring orator that defines certainty in terms of consensus. As part of a larger discussion of argumentative strategies, Quintilian turns to the “nature of all arguments,” which he defines as “reasoning which lends credence to what is doubtful by means of what is certain” (ratio per ea quae certa (...) sunt fidem dubiis adferens: quae natura est omnium argumentorum, V.10.8). These certainties, he later specifies, include not matters of scientific demonstration or objective fact, but the agreements of various communities: the laws of cities, local customs, and other forms of consensus. As the foundation of persuasive rhetoric, these consensus-based certainties situate argumentation as the practice of crafting agreements rather than demonstrating necessary conclusions. Taking as its point of departure Quintilian's novel understanding of certainty, this study looks to some of Quintilian's intellectual forebears as well as his later readers to show how his work is both a nexus of earlier intellectual developments as well as an important inspiration for later accounts of certainty, even into the early modern period. After illustrating in the first chapters of this dissertation how Quintilian's manual incorporates elements from Aristotelian notions of dialectic and rhetoric as well as from Ciceronian skeptical approaches to epistemology, I show how Quintilian's curriculum for the orator shapes the thought of Italian humanists, especially that of Lorenzo Valla (1406–1457), a reformer of scholastic logic and dialectic, and Giambattista Vico (1668–1744), an influential Neapolitan jurist. Adopting Quintilian's rendering of certainty as a matter of agreements and conventions, these later authors elaborate their own novel approaches to various fields—including law, language, and logic—through this ancient understanding of certum. Contrary to modern notions of certainty as objective or scientific fact, Quintilian's humanist readers continue to root this concept in consensus, both within the courtroom and without. (shrink)

Why are enthymemes so frequent? Are we dumb arguers, smart rhetoricians, or parsimonious reasoners? This paper investigates systematic use of enthymemes, criticizing the application of the principle of charity to their interpretation. In contrast, I propose to analyze enthymematic argumentation in terms of parsimony, i.e. as a manifestation of the rational tendency to economize over scant resources. Consequences of this view on the current debate on enthymemes and on their rational reconstruction are discussed.