Traditionally, a presumption is a dialogically privileged, yet defeasible proposition that allocates the burden of proof to a party who challenges it. This paper investigates the strength of presumptions. First, it explains how ‘strength’ contributes to defining the concept of presumption. Second, it provides an overview of (contextual, justificatory, and deontic) factors determining a presumption’s strength. Finally, it analyses the predominant view that defines strength in terms of the Challenger’s burden of proof: the stronger (weaker) the presumptionp, the more (less) (...) difficult it is to prove non-p. I argue that the latter proposal applies only to practical presumptions, and that strength is conceived differently for cognitive presumptions. (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.

In the first part of this paper I consider the Gricean account of communication, as structured by the Cooperative Principle and the four maxims. Several authors, including Jean Goodwin [10], Fred Kauffeld [17], Michael Gilbert [7], Ernie Lepore and Mathew Stone [22], among others, argue that the Gricean view of communication fails in as much as it pretends to offer an account of all such human interactions. As Goodwin and Kauffeld suggest, a more promising starting point is to consider the (...) variety of contextually determined presumptions that we make about speakers and that we rely upon in interpreting utterances. These presumptions are established in various ways, and are dropped, or defeated, in certain conditions. In order to clarify these aspects we need to inquiry into the nature of presumptions. I argue that Kauffeld’s [18], [19], [20] account of presumptions is useful in this context. In the second part of the paper I look at what this account tells us about how, and in what conditions, presumptions in communication are rebutted. (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 responds to Kauffeld’s 2009 OSSA paper, considering the adequacy of his “commitment-based” approach to “ordinary presumptive practices” to sup-ply an account of presumption fit for general application in normative theories of argument. The central issue here is whether socially-grounded presumptions are defeasible in the right sorts of ways so as to pro-duce “truth-tropic” presumptive inferences.

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.