The Uniqueness Thesis (U), according to Richard Feldman and Roger White, says that for a given set of evidence E and a proposition P, only one doxastic attitude about P is rational given E. Luis Rosa has recently provided two counterexamples against U which are supposed to show that even if there is a sense in which choosing between two doxastic attitudes is arbitrary, both options are equally and maximally rational. Both counterexamples work by exploiting the idea that ‘ought implies (...) can’ and trying to spell out situations in which some inferences are beyond the capabilities of some reasoners. I argue that on a descriptive account of doxastic rationality, questions of whether ‘epistemic ought implies can’ can be bracketed and that at least one of the inferential moves that Rosa describes in his cases is irrational. I further argue that a descriptive account of doxastic rationality is the appropriate notion of rationality that is to be considered when evaluating U. If my argument for a descriptive account of rationality is successful, then we have reason to revise our use of the term rationality to fit this descriptive understanding. (shrink)

On the standard version of political liberalism, the exercise of political power is legitimate only if it is justifiable to all reasonable persons. Correspondingly, reasonable disagreement about the moral doctrines underlying a law makes that law not justifiable to all reasonable persons. In this paper, I argue that political liberals are committed to understanding reasonable disagreement as being rational, rather than praiseworthy disagreement between morally reasonable person because other conceptions of reasonableness commit them to an incoherent triad of claims.