Uniqueness: Evidential Support, Evidence, and Rationality

Uniqueness is an extremely demanding view about the relationship between evidence and rational belief: it holds that our evidence determines exactly what it is rational for us to believe with respect to any given proposition. The aim of this thesis is to identify and interrogate some of the crucial – but not currently recognised – assumptions about evidential support, evidence, and rationality underlying many of the arguments given for Uniqueness. These are assumptions about the very epistemic considerations proponents of Uniqueness tell us are best captured by this view. However, I argue that on each of these focal points, proponents of Uniqueness end up being committed to something implausible