 In this section, we consider alternative sets of conditions on inaccuracy measures that are presented by Leitgeb &amp; Pettigrew (2010a). These propose that we replace the claim  Joycean Inaccuracy  in Joyce’s accuracy argument for Probabilism with an alternative claim that says that the legitimate inaccuracy measures are (amongst) those that satisfy Leitgeb and Pettigrew’s alternative conditions. Unlike Joyce’s conditions, these are sufficient to narrow the field of legitimate inaccuracy measures to just a single one, namely, the Brier score \(\mathfrak{B}\) that we met in  section 5.1  above. Let us say that Brier Inaccuracy is the claim that the Brier score is the only legitimate measure of inaccuracy. And note that, if we replace  Joycean Inaccuracy  with Brier Inaccuracy in Joyce’s argument for Probabilism, we retain our argument for that epistemic norm: