Boghossian, Bellarmine, and Galileo: Adjudication and epistemic relativism

Many prominent arguments for epistemic relativism take their departure from the observation that a certain kind of epistemic symmetry is present in particular empirical cases. In this paper, we seek to attain further clarity about the kind of symmetry at issue, and the sort of relativism to which such symmetry can reasonably be taken to give rise. The need for such an investigation is made apparent, we believe, by the fact that prominent anti-relativist arguments such as that advanced by Boghossian in his influential book Fear of Knowledge (2006) yield distorted pictures of the matter. Following Boghossian, we present our argument through a detailed consideration of the dispute between Bellarmine and Galileo concerning heliocentrism. Contrary to what Boghossian claims, the relevant sort of symmetry does not concern a difference in fundamental epistemic principles between Bellarmine and Galileo, but rather a much more localized difference in procedures for adjudication between shared principles in the novel epistemic circumstances generated by Galileo's telescopic observations. Bellarmine and Galileo advance fundamentally different procedures of adjudication that are nevertheless equally rational. The upshot is not so much the denial that there are absolute epistemic facts as such, as Boghossian thinks, but rather the denial that there is an absolute fact of the matter as to which was the most rational way to proceed: Bellarmine's or Galileo's. What this gives us, is the denial that there is a certain kind of absolute epistemic fact.