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)

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)

Accounts of analogical inference are usually categorized into four broad groups: abductive, deductive, inductive and sui generis. The purpose of this paper is to defend a sui generis model of analogical inference. It focuses on the sui generis account, as developed by Juthe [2005, 2009, 2015, 2016] and Botting’s [2017] criticism of it. This paper uses the pragmadialectical theory of argumentation as the methodological framework for analyzing and reconstructing argumentation. The paper has two main points. First, that Juthe’s arguments against (...) a deductive interpretation of prima facie analogy argumentation remain unaffected by Botting’s criticism, which means that many of the reasons against deductive reformulation of analogy argumentation still stand. The additional argument, which Botting himself brings up, that a deductive interpretation cannot account for the cumulative effect of analogies, just provides further reason to reject deductivism. The second main point of this paper is that an inductive interpretation of analogical inference also fails. There are constitutional differences between inductive and analogical inference that cannot be bridged. The result is a firm defense of the sui generis view of analogical inference. (shrink)