  On the one hand, “rationality demands” that upon his acquisition of new knowledge Bub drop his belief \(J\) that Japan is a totalitarian state: after all, his overall evidence for it is very weak. On the other hand, “rationality demands” that upon his acquisition of new knowledge Bub keep his belief \(J\) given that that acquisition—which is the only thing that’s happened to him—gives him no reason to doubt \(J\). This situation still might strike you as odd. After all, we’re saying that Bub is being rational in keeping an irrational belief! But no: that’s not what we’re saying. The statement ‘Bub is being rational’ is ambiguous: is it saying that Bub’s retained belief \(J\) is rational or is it saying that Bub’s retaining of that belief was rational? The statement can take on either meaning, and the two meanings end up with different verdicts: the retained belief is irrational but the retaining of the belief is rational. In the first case, a state is being evaluated, in the second, an action is being evaluated.