This paper outlines an integrated approach to trust and relevance with respect to arguments: in particular, it is suggested that trust in relevance has a central role in argumentation. We first distinguish two types of argumentative relevance: internal relevance, i.e. the extent to which a premise has a bearing on its purported conclusion, and external relevance, i.e. a measure of how much a whole argument is pertinent to the matter under discussion, in the broader dialogical context where it is proposed. (...) Then, we argue that judgements of internal relevance heavily rely on trust, and that such trust, although occasionally misplaced , is nonetheless based on several reasons, and thus often justified, by either epistemic or pragmatic considerations. We conclude by sketching potential methods to formally model trust in argumentative relevance, and briefly discussing the technological implications of this line of research. (shrink)

In this paper a theoretical definition that helps to explain how the logical structure of legal presumptions is constructed by applying the Carneades model of argumentation developed in artificial intelligence. Using this model, it is shown how presumptions work as devices used in evidentiary reasoning in law in the event of a lack of evidence to assist a chain of reasoning to move forward to prove or disprove a claim. It is shown how presumptions work as practical devices that may (...) be useful in cases in which there is insufficient evidence to prove the claim to an appropriate standard of proof. (shrink)

In their extensive overview of various concepts of presumption Godden and Walton recognise “the heterogeneous picture of presumptions that exists in argumentation theory today”. I argue that this heterogeneity results from an epiphenomenal character of the notion of presumption. To this end, I first distinguish between three main classes of presumptions. Framework presumptions define the basic conditions of linguistic understanding and meaningful conversation. The “presumption of veracity” is their paradigm case. I argue that such presumptions are satisfactorily covered by the (...) Principle of Charity, or else Gricean maxims or satisfaction conditions for speech acts. Formal presumptions are general presumptive rules of argument, theorised as topoi or acceptable inference warrants, including institutional warrants. Material presumptions are acceptable outcomes of nested or outsourced arguments, which entitles arguers to use them as acceptable premises or opinions in further arguments without the typical burden of proof. If this is correct, then the study of presumption always collapses into the study of other, likely more fundamental, concepts. Does it render presumptions, by Occam’s Razor, altogether redundant in argumentation theory? I tentatively answer this question from a consistently conversational perspective on argumentation; I argue that the pragmatic grounds for presumptions are to be found in the conditions for speech act performance in the institutional social world, as developed by Searle. (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)

This paper explores two persistent questions in the literature on presumptions: the place and the nature of presumptions in law and legal argumentation. These questions were originally raised by James Bradley Thayer, one of the masters of the Law of Evidence and the author of the classic chapter devoted this subject in A preliminary treatise on Evidence. Like Thayer, I believe that these questions deserve attention. First the paper shows that the connection between presumptions and argumentation is a constant feature (...) in the literature on presumptions, since its foundation in the Middle Ages to modern times. James Bradley Thayer was probably the last jurist who clearly saw that presumptions belong to argumentation. Second, the paper examines two sources of controversy in the language of presumptions. First, “presumption” is an ambiguous word in the legal discourse. As a result, it is almost impossible to provide a clear and succinct answer to the question “What is a presumption?”. Second, there are at least four reconstructions of the concept of presumption whose merits and shortcomings are relevant to explore. The analysis presented here may be of interest for legal and non-legal scholars and, hopefully, it may help to shed light on the possibilities and limits of an interdisciplinary dialogue about presumptions. (shrink)

The aim of this paper is to explore the viability of accounting for presumptions as a subtype of verdictives, within the framework of the Austinian approach to speech acts. The available set of felicity conditions is examined and worked out, in order to try and account in particular for a main feature of presumptions, namely, their function in shifting the burden of proof. In order to extend the Austinian framework as required, the notion of pragmatic presupposition accommodation is shown to (...) be a useful device. (shrink)

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)

From 26th to 28th of April 2016, it took place in the University of Granada a conference on presumptions, presumptive inferences and burdens of proof that, joint with other ongoing initiatives, has contributed to renew the interest of the argumentation community in analysing these notions and the relationships between them. This special volume of Argumentation consists of a selection of papers presented at this conference.

How is the burden of proof to be distributed among individuals who are involved in resolving a particular issue? Under what conditions should the burden of proof be distributed unevenly? We distinguish attitudinal from dialectical burdens and argue that these questions should be answered differently, depending on which is in play. One has an attitudinal burden with respect to some proposition when one is required to possess sufficient evidence for it. One has a dialectical burden with respect to some proposition (...) when one is required to provide supporting arguments for it as part of a deliberative process. We show that the attitudinal burden with respect to certain propositions is unevenly distributed in some deliberative contexts, but in all of these contexts, establishing the degree of support for the proposition is merely a means to some other deliberative end, such as action guidance, or persuasion. By contrast, uneven distributions of the dialectical burden regularly further the aims of deliberation, even in contexts where the quest for truth is the sole deliberative aim, rather than merely a means to some different deliberative end. We argue that our distinction between these two burdens resolves puzzles about unevenness that have been raised in the literature. (shrink)

The involvement of social considerations in our ordinary conception of presumption and corresponding plain practice of presuming things raises doubts as to whether they afford epistemically satisfying bases for rational argumentation. To some this involvement illuminates important modes of discursive inquiry; to others it points to the need for theoretically based reform or regulation of our ordinary practices. This paper attempts to clarify and defend the epistemic value of ordinary presumptions.