ABSTRACTIn everyday situations, people regularly receive information from large groups of people and from single experts. Although lay opinions and expert opinions have been studied extensively in isolation, the present study examined the relationship between the two by asking how many laypeople are needed to counter an expert opinion. A Bayesian formalisation allowed the prescription of this quantity. Participants were subsequently asked to assess how many laypeople are needed in different situations. The results demonstrate that people are sensitive to the (...) relevant factors identified for determining how many lay opinions are required to counteract a single expert opinion. People's assessments were fairly good in line with Bayesian predictions. (shrink)

One explanation of rational peer disagreement is that agents find themselves in an epistemically permissive situation. In fact, some authors have suggested that, while evidence could be impermissive at the intrapersonal level, it is permissive at the interpersonal level. In this paper, I challenge such a claim. I will argue that, at least in cases of rational disagreement under full disclosure, there cannot be more interpersonal epistemically permissive situations than there are intrapersonal epistemically permissive situations. In other words, with respect (...) to cases of disagreement under full disclosure, I will argue that there is a necessary connection between interpersonal permissiveness and its intrapersonal counterpart. Specifically, I claim that a plausible principle of correct argumentation supports such a bridge. (shrink)

In this paper, close attention is paid to the argumentative patterns resulting from combining pragmatic argumentation in which a recommendation is made with arguments in which the majority is invoked. I focus on such argumentative patterns as employed by European parliamentary committees of inquiry conducting inquiries into the activity of the Equitable Life Assurance Society. By incorporating legal and political insights about the activity of these parliamentary committees of inquiry into a pragma-dialectical argumentative approach, an analysis will be given of (...) the selected argumentative pattern. This analysis will reveal which standpoints are supported by which arguments and how these arguments relate to each other to increase the acceptability of the recommendation made. In addition, the analysis will explain the arguer’s argumentative choices in the pattern employed. (shrink)

Knowledge plays an important role in argumentation. Yet, recent work shows that standard conceptions of knowledge in epistemology may not be entirely suitable for argumentation. This paper explores the role of knowledge in argumentation, and proposes a notion of knowledge that promises to be more suitable for argumentation by taking account of: its dynamic nature, the defeasibility of our commitments, and the non-monotonicity of many of the inferences we use in everyday reasoning and argumentation.

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)