Enthymemes: From Reconstruction to Understanding

Traditionally, an enthymeme is an incomplete argument, made so by the absence of one or more of its constituent statements. An enthymeme resolution strategy is a set of procedures for finding those missing elements, thus reconstructing the enthymemes and restoring its meaning. It is widely held that a condition on the adequacy of such procedures is that statements restored to an enthymeme produce an argument that is good in some given respect in relation to which the enthymeme itself is bad. In previous work, we emphasized the role of parsimony in enthymeme resolution strategies and concomitantly downplayed the role of “charity”. In the present paper, we take the analysis of enthymemes a step further. We will propose that if the pragmatic features that attend the phenomenon of enthymematic communication are duly heeded, the very idea of reconstructing enthymemes loses much of its rationale, and their interpretation comes to be conceived in a new light.     

Enthymematic parsimony

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.     

Representation of Argumentation in Text with Rhetorical Structure Theory

Various argumentation analysis tools permit the analyst to represent functional components of an argument (e.g., data, claim, warrant, backing), how arguments are composed of subarguments and defenses against potential counterarguments, and argumentation schemes. In order to facilitate a study of argument presentation in a biomedical corpus, we have developed a hybrid scheme that enables an analyst to encode argumentation analysis within the framework of Rhetorical Structure Theory (RST), which can be used to represent the discourse structure of a text. This paper describes the hybrid representation scheme and illustrates its use for investigation of contexts that license omission of elements of an argument. The analyses given in the paper involve reconstruction of enthymemes. Defeasible argumentation schemes serve as a constraint on reconstruction. In addition, the examples illustrate several other types of contextual constraints on reconstruction of enthymemes.     

Argumentation Without Arguments

A well-known ambiguity in the term ‘argument’ is that of argument as an inferential structure and argument as a kind of dialogue. In the first sense, an argument is a structure with a conclusion supported by one or more grounds, which may or may not be supported by further grounds. Rules for the construction and criteria for the quality of arguments in this sense are a matter of logic. In the second sense, arguments have been studied as a form of dialogical interaction, in which human or artificial agents aim to resolve a conflict of opinion by verbal means. Rules for conducting such dialogues and criteria for their quality are part of dialogue theory. Usually, formal accounts of argumentation dialogues in logic and artificial intelligence presuppose an argument-based logic. That is, the ways in which dialogue participants support and attack claims are modelled as the construction of explicit arguments and counterarguments (in the inferential sense). However, in this paper formal models of argumentation dialogues are discussed that do not presuppose arguments as inferential structures. The motivation for such models is that there are forms of inference that are not most naturally cast in the form of arguments (such as abduction, statistical reasoning and coherence-based reasoning) but that can still be the subject of argumentative dialogue. Some recent work in artificial intelligence is discussed which embeds non-argumentative inference in an argumentative dialogue system, and some general observations are drawn from this discussion.     

The Common Topic in Aristotle’s <Emphasis Type="Italic">Rhetoric</Emphasis>: Precursor of the Argumentation Scheme

In the present article I attribute to the common topic in the Rhetoric a two-fold suggestive function and a guarantee function. These three functions are possible because this type of topic, while often quite abstract, nevertheless contains thought-steering, substantial terms, and formulates a generally empirical or normative endoxon. Assuming that according to Aristotle an enthymeme has at least two premises, it would appear that a common topic is the abstract principle behind the often implicit major premise. This means that the topic may be regarded as the – generalizing – if-then statement in a modern argumentation scheme. Therefore it should be possible to see the enthymemes of Rhetoric 2.23 as a combination of a logical argument form (which can usually be reconstructed as modus ponens) and an argumentation scheme – even though we may not attribute this idea to Aristotle himself.     

The Sunk Costs Fallacy or Argument from Waste

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.     

Evaluating Practical Reasoning

In this paper, the defeasible argumentation scheme for practical reasoning (Walton 1990) is revised. To replace the old scheme, two new schemes are presented, each with a matching set of critical questions. One is a purely instrumental scheme, while the other is a more complex scheme that takes values into account. It is argued that a given instance of practical reasoning can be evaluated, using schemes and sets of critical questions, in three ways: by attacking one or more premises of the argument, by attacking the inferential link between the premises and conclusion, or by mounting a counter-argument. It is argued that such an evaluation can be carried out in many cases using an argument diagram structure in which all components of the practical reasoning in the case are represented as premises, conclusions, and inferential links between them that can be labeled as argumentation schemes. This system works if every critical question can be classified as a assumption of or an exception to the original argument. However, it is also argued that this system does not work in all cases, namely those where epistemic closure is problematic because of intractable disputes about burden of proof.     

Epistemic and Dialectical Models of Begging the Question

This paper addresses the problem posed by the current split between the two opposed hypotheses in the growing literature on the fallacy of begging the question the epistemic hypothesis, based on knowledge and belief, and the dialectical one, based on formal dialogue systems. In the first section, the nature of split is explained, and it is shown how each hypothesis has developed. To get the beginning reader up to speed in the literature, a number of key problematic examples are analyzed illustrating how both approaches can be applied. Useful tools are brought to bear on them, including the automated argument diagramming system Araucaria, and profiles of dialogue used to represent circular argumentation in a dialogue tableau format. These tools are used to both to model circular reasoning and to provide the contextual evidence needed to properly determine whether the circular reasoning in a given case is better judged fallacious or not. A number of technical problems that have impeded the development of both hypotheses are studied. One central problem is the distinction between argument and explanation. It is concluded that the best way to move forward and solve these problems is to reformulate the two hypotheses in such a way that they might be able to co-exist. On this basis, a unified methodology is proposed that allows each hypothesis to move forward as a legitimate avenue for research using the same tools.     

Image Events, the Public Sphere, and Argumentative Practice: The Case of Radical Environmental Groups

Operating from the assumption that a primary dynamic of contemporary public argument involves the use of visual images the authors explore the argumentative possibilities of the `image events' (staged protests designed for media dissemination) employed by radical ecology groups. In contextualizing their discussion, the authors offer an analysis of the contemporary conditions for argumentation by describing the character and operation of public communication, social problem creation, and public opinion formation in a mass-mediated public sphere. The authors argue that image events are a form of postmodern argumentative practice, a kind of oppositional argument that creates social controversy, and animates and widens possibilities for debate. They further suggest that image events are a postmodern form of argument involving acts of protest which deliver images as argumentative fragments. Employing the tools of traditional argument theory the authors describe how images are capable of offering unstated propositions and advancing indirect and incomplete claims in ways that function to block enthymemes and advance alternatives. In concluding, the authors discuss the implications of image events for our understanding of the public sphere and the possibilities for argumentation in a postmodern age.     

Defeasible reasoning and informal fallacies

This paper argues that some traditional fallacies should be considered as reasonable arguments when used as part of a properly conducted dialog. It is shown that argumentation schemes, formal dialog models, and profiles of dialog are useful tools for studying properties of defeasible reasoning and fallacies. It is explained how defeasible reasoning of the most common sort can deteriorate into fallacious argumentation in some instances. Conditions are formulated that can be used as normative tools to judge whether a given defeasible argument is fallacious or not. It is shown that three leading violations of proper dialog standards for defeasible reasoning necessary to see how fallacies work are: (a) improper failure to retract a commitment, (b) failure of openness to defeat, and (c) illicit reversal of burden of proof.     

Medieval Disputationes de obligationibus as Formal Dialogue Systems

Formal dialogue systems model rule-based interaction between agents and as such have multiple applications in multi-agent systems and AI more generally. Their conceptual roots are in formal theories of natural argumentation, of which Hamblin’s formal systems of argumentation in Hamblin (Fallacies. Methuen, London, 1970, Theoria 37:130–135, 1971) are some of the earliest examples. Hamblin cites the medieval theory of obligationes as inspiration for his development of formal argumentation. In an obligatio, two agents, the Opponent and the Respondent, engage in an alternating-move dialogue, where the Respondent’s actions are governed by certain rules, and the goal of the dialogue is establishing the consistency of a proposition. We implement obligationes in the formal dialogue system framework of Prakken (Knowl Eng Rev 21(2):163–188, 2006) using Dynamic Epistemic Logic (van Ditmarsch et al. in Dynamic epistemic logic, Synthese Library Series. Springer, Berlin, 2007). The result is a new type of inter-agent dialogue, for consistency-checking, and analyzing obligationes in this way also sheds light on interpretational and historical questions concerning their use and purpose in medieval academia.     

Formalization of the ad hominem argumentation scheme

In this paper, several examples from the literature, and one central new one, are used as case studies of texts of discourse containing an argumentation scheme that has now been widely investigated in literature on argumentation. Argumentation schemes represent common patterns of reasoning used in everyday conversational discourse. The most typical ones represent defeasible arguments based on nonmonotonic reasoning. Each scheme has a matching set of critical questions used to evaluate a particular argument fitting that scheme. The project is to study how to build a formal computational model of this scheme for the circumstantial ad hominem argument using argumentation tools and systems developed in artificial intelligence. It is shown how the formalization built using these tools is applicable to the tasks of identification, analysis and evaluation of the central case studied. One important implication of the work is that it provides a foundational basis for showing how other argumentation schemes can be formalized.     

Coping with ambiguity and uncertainty in patient-physician relationships: II.Traditio argumentum respectus

A methodology of argumentation and a perspective of incredulity are essential ingredients of all intellectual endeavor, including that associated with the art and science of medical care.Traditio argumentum respectus (tradition of respectful argumentation) as a principled system of assessing the validity of beliefs, opinions, perceptions, data, and knowledge, is worthy of practice and perpetuation, because assessments of validity are susceptible to incompleteness, incorrectness, and misinterpretation. Since the latter may lead to ambiguity, uncertainty, anxiety, and animosity among the individuals (patients and physicians) involved in such dialogue, objective analyses and criteria are desirable. A tradition of respectful argumentation is a means to this end—to maximize objectivity and minimize subjectivity as part of decision-making processes and to preserve the integrity of the participants in a patient-physician relationship. During such discourse one must always be cognizant of fallacious arguments—material, verbal, and formal fallacies—since they compromise the validity of assertions. This essay summarizes a classification of fallacious arguments, by definition and by example, predicated upon the intellectual tradition of Occidental Society; and advocates a tradition of respectful argumentation to nullify them.     

Argument practices

The move to Postmodernism in argumentation is often predicated on the rejection of the formal basis of argument in logic. While this rejection may be justified, and is widely discussed in the literature, the loss of logic creates problems that a Postmodern theory of argument must address without recourse to logic and its attendant modernist assumptions. This essay argues that conceiving of argument in terms ofpractices will address the key problematics of Postmodernism without abandoning those features of argumentation that make it an important social, cultural and political practice. Implications for both theory and pedagogy are discussed.The author would like to acknowledge the invaluable commentary of, and discussions with, John Lyne, Charles Willard, Steven Fuller, and Ed Schiappa.     

Formal Logic vs. Philosophical Argument

The wider topic to which the content of this paper belongs is that of the relationship between formal logic and real argumentation. Of particular potential interest in this connection are held to be substantive arguments constructed by philosophers reputed equally as authorities in logical theory. A number of characteristics are tentatively indicated by the author as likely to be encountered in such arguments. The discussion centers afterwards, by way of specification, on a remarkable piece of argument quoted in Cicero’s dialog On Divination and ascribed to Stoic thinkers. The Stoics’ formal theory of inference is summarily referred to in this context, with special emphasis on their basic deductive schemata (‘indemonstrables’), some of them recognizable as links in the overall structure of the quoted argument. The main lines of Cicero’s criticism of the Stoic argument are next commented upon, with emphasis on his implied view as to the requirements of a good argument. Towards the end of the paper, a few considerations are added on the changes in the prevailing style of argumentation conspicuous in the three famous Roman Stoics.     

Story Problems: Where Do the Agonists of the Dialogue Model of Argument Interact?

When discussing dialogue, argumentation researchers rarely draw the distinction between the story world and interactional world. While mediators often help to shape the interactions among agonists in the emerging flow of spoken discourse, writers of postulated dialogues narrate them, constructing a story world that depicts the agonists, depicts their utterances and their circumstances. In this paper, I ask where the agonists of the dialogue model of argument interact, and I show that they often interact in the story world of postulated dialogues. Postulated dialogues are story problem conversations. Common in textbooks, exams, and standardized tests, story problems create hypothetical situations to illustrate formal relationships among variables, and are designed to be read in a theoretical attitude that treats the characters, objects, and circumstances that they depict as given. When argumentation researchers examine postulated dialogues, they tend to adopt a theoretical attitude, limiting their analysis to the conversation between the agonists depicted in the story world. Reading this way makes it easier to overlook the interactional world where the writing and reading of the texts takes place, obscuring the fact that they are narrated dialogues, often written by researchers. Reading this way also makes it easier to confirm the traditional participation framework of the dialogue model of argument.     

The Value of Topoi

Despite Vancil’s (1979) proclamation over twenty years ago that topoi have been abandoned in argument theory, this essay contends that topoi should have a vital role in contemporary argumentation theory. Four key areas are identified where topoi are (or can be) essential tools for argumentation: Locating argument, building argument, development of critical thinking, and argument pedagogy. As a result, teachers and students of argument can both benefit from a (re)discovery of topoi.     

Argumentation Schemes and Enthymemes

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.