Martina Calderisi

The focus of this paper will be on an argument that has been recently put forward by Kevin Dorst against the desirability of the irrationalist explanation of the phenomenon of group polarization. I will show that this argument is unsound, as it crucially relies on an implausible interpretation of the notion of higher-order inaccuracy in the epistemic domain. To do so, it will prove useful to discuss two alternative ways of formalizing the principle ruling out inaccurate higher-order beliefs, which I will call the Non-Inaccuracy Constraint. Arguments structurally similar to Dorst’s one might be raised against the desirability of irrationalist explanations of other phenomena. My objection to Dorst’s argument would apply to them as well, and consequently its scope goes beyond the case of polarization.

McGee notably provided a putative counterexample to Modus Ponens. McGee’s puzzle is based on a scenario involving three candidates running for president in the 1980 United States elections. We will present a slightly modified version of McGee’s election scenario, in which the probability of one of the candidates (i.e., Ronald Reagan) winning is reduced to a conveniently low value. As we will see, two ways out of the puzzle, suggested by Fulda and Paoli respectively, do not survive this minor change in the scenario. In addition, we will point to the fact that our modified election scenario also gives rise to a lottery-style paradox.

Does the most common response given by participants presented with Tversky and Kahneman’s famous taxi cab problem amount to a violation of Bayes’ theorem? In other words, do they fall victim to so-called base-rate fallacy? In the present paper, following an earlier suggestion by Crupi and Girotto, we will identify the logical arguments underlying both the original diagnosis of irrationality in this reasoning task under uncertainty and a number of objections that have been raised against such a diagnosis. This will enable us to show firstly that, contrary to the dismissive arguments recently put forward by Elqayam and Evans, empirical evidence turns out to be quite useful in addressing questions of this kind. Therefore, it can make a significant contribution to moving the base-rate fallacy controversy forward. Secondly, the available empirical evidence (though limited and sometimes inconclusive) seems to support the charge of irrationality levelled against the majority of participants presented with the taxi cab problem, and hence suggests that base-rate neglect is a real fallacy − that is the conclusion of our analysis.