Abstract

According to the popular ‘epistemic virtue account’ (EVA) of theory choice, we should choose between scientific theories on the basis of their epistemic virtues: empirical fit, simplicity, unity etc. More specifically, we should use a rule that aggregates theories’ virtues into a ranking of the overall goodness of the theories. However, an application of Arrow’s impossibility theorem shows that, given plausible premises, there is no rule that can aggregate theories’ virtues into a theory ranking. The EVA-supporter might try to avoid the impossibility result of Arrow’s theorem by asserting that we have more fine-grained distinctions between theories’ epistemic virtues than initially supposed. We show that implausibly fine-grained distinctions between virtue quantities are necessary to escape the impossibility result. This is shown via novel proofs of Arrow’s theorem for cases in which the quantities to be aggregated are measured on any combination of different scales of information, as is likely the case when aggregating epistemic virtues.