Jonah N. Schupbach

In, I put forward a “possibility result” for Bayesian Coherentism, showing that there exist plausible sets of ceteris paribus conditions that imply that coherence is truth-conducive. Against this result, Schubert argues that the specific ceteris paribus conditions I consider are “jointly inconsistent”. In this article, I prove to the contrary that these conditions can consistently be enforced while allowing degrees of coherence to vary. Next, I consider a related criticism, inspired by Olsson’s constraints on ceteris paribus conditions. This leads to a general discussion of the principle that should guide one in choosing appropriately stringent ceteris paribus conditions.En planteo un “resultado de posibilidad” para el bayesianismo coherentista mostrando que existen conjuntos plausibles de condiciones ceteris paribus que implican que la coherencia conduce a la verdad. Schubert argumenta en contra de este resultado que las condiciones ceteris paribus que considero son “inconsistentes tomadas conjuntamente”. En este articulo demuestro, sin embargo, que estas condiciones pueden ser satisfechas permitiendo que los grados de coherencia varien. Abordo despues una critica relacionada con la anterior e inspirada en los requisitos impuestos por Olsson a las condiciones ceteris paribus. Eso lleva a una discusion general del principio, o principios, que deberia guiarnos para elegir unas condiciones ceterisparibus que sean apropiadas, es decir, que no sean ni muy restrictivas, ni demasiado laxas.

Crupi et al. (2008) offer a confirmation-theoretic, Bayesian account of the conjunction fallacy—an error in reasoning that occurs when subjects judge that Pr( h 1 & h 2 | e ) > Pr( h 1 | e ). They introduce three formal conditions that are satisfied by classical conjunction fallacy cases, and they show that these same conditions imply that h 1 & h 2 is confirmed by e to a greater extent than is h 1 alone. Consequently, they suggest that people are tracking this confirmation relation when they commit conjunction fallacies. I offer three experiments testing the merits of Crupi et al.’s account specifically and confirmation-theoretic accounts of the conjunction fallacy more generally. The results of Experiment 1 show that, although Crupi et al.’s conditions do seem to be causally linked to the conjunction fallacy, they are not necessary for it; there exist cases that do not meet their three conditions in which subjects still tend to commit the fallacy. The results of Experiments 2 and 3 show that Crupi et al.’s conditions, and those offered by other confirmation-theoretic accounts of the fallacy, are not sufficient for the fallacy either; there exist cases that meet all three of CFT’s conditions in which subjects do not tend to commit the fallacy. Additionally, these latter experiments show that such confirmation-theoretic conditions are at best only weakly causally relevant to the presence of the conjunction fallacy. Given these findings, CFT’s account specifically, and any general confirmation-theoretic account more broadly, falls short of offering a satisfying explanation of the presence of the conjunction fallacy.