We consider a proportional-prize contest to forecast future events, and show that, in equilibrium, this mechanism possesses perfect forecasting ability for any group size when the contestants share common knowledge about the probabilities by which future events realize. Data gathered in a laboratory experiment confirm the performance invariance to group size. By contrast, when realization probabilities are not common knowledge, there are some differences across group sizes. The mechanism operates marginally better with three or four compared to two players. However, (...) this effect is mainly driven by players’ behavior rather than by differences in the beliefs they form about the realization probabilities. (shrink)

Unlike the majority of philosophers, Hannah Arendt was not inclined to look down on common sense. She became convinced of common sense’s invaluable significance for our common world, especially when she came to understand that totalitarianism consists of its undermining. No matter how important the role of the concept in her thought, however, its meaning remains ambiguous insofar as it refers to two related, yet different ‘faculties’, common sense as a cognitive faculty on the one hand and common sense as (...) a faculty of judgment on the other. The aim of this two-part paper is to clarify this complicated relation.The first part sketches the development of the concept and demonstrates how the polemic created by Eichmann in Jerusalem sharpened Arendt’s understanding of the difference between truth and opinion, knowing and judging. Subsequently, it focuses on Arendt’s analysis of common sense as a cognitive faculty, i.e. as a ‘sixth sense’ that enables us to grasp the common and worldly context of our experiences and therefore also enables us to tell truth from falsehood. It is not thinking, with its search for meaning, but our common sense that warrants the revelation of truth and with it the possibility of knowledge . Because truth compels the mind and precludes debate, Arendt distinguishes it sharply from opinion, which is never self-evident.Nevertheless, this distinction does not end, as in Plato, in the hierarchical subordination of opinion to truth . At the same time, Arendt was aware of the powerlessness and vulnerability of truth in the public forum, in spite of its compelling character. This paradox calls for a discussion of Arendt’s view on the possibilities and limitations of modern mass-manipulation. (shrink)

This paper investigates the determinants of cost-(in)effective giving to public goods. We conduct a pre-registered experiment to elucidate how factors at the institutional and individual levels shape individual contributions and the cost-effectiveness of those contributions in a novel public good game. In particular, we examine the role of consequential uncertainty over the value of public good contributions (institutional level) as well as individual characteristics like risk and ambiguity attitudes, giving type, and demographics (individual level). We find cost-ineffective contributions in all (...) institutions, but total contribution levels and the degree of cost-ineffectiveness are similar across institutions. Meanwhile, cost-effectiveness varies by giving type—which is a novel result that is consistent with hypotheses we generate from theory—but other individual characteristics have little influence on the cost-effectiveness of contributions. Our work has important positive and normative implications for charitable giving and public good provision in the real world, and it is particularly germane to emerging online crowdfunding and patronage platforms that confront users with a multitude of competing opportunities for giving. (shrink)