One of the major epistemological developments in recent decades is the ascent of Bayesianism. Despite its popularity, Bayesianism faces a recurrent complaint: the theory is overly demanding. For example, Bayesianism entails that we should have credence 1 in every logical truth—a bar that not even the most astute logicians meet.
A common response maintains that Bayesianism is a theory of ideal rationality. Ordinary mortals count as rational insofar as they approximate this ideal. But this response gives rise to two questions. First, what does it mean to “approximate” the Bayesian ideal? Second, what’s the point of approximating the Bayesian ideal—why toil toward a goal that we will never reach?
Surprisingly, neither question has received much attention. Luckily, Julia Staffel’s Unsettled Thoughts (hereafter, US) is here to fill this lacuna.
US is a tour de force, developing an ambitious research program that will set the agenda for future discussion of...
