Fragmentation and Higher-Order Evidence

The concept of higher-order evidence—roughly, evidence about what our evidence supports—promises epistemological riches; it has struck many philosophers as necessary for explaining how to rationally respond to disagreement in particular, and to evidence of our own fallibility more generally. But it also threatens paradox. Once we allow higher-order evidence to do non-trivial work—in particular, once we allow that people can be rationally ignorant of what their evidence supports—we seem to be committed to a host of puzzling or even absurd consequences. The aim in this chapter is to have our cake and eat it too; it presents an independently motivated framework that lets us mimic the particular case judgments of those who explain how to accommodate evidence of our fallibility by appeal to higher-order evidence, but without commitment to the absurd consequences.