 How large is “largely”? The lines of demarcation are not sharp, and subjective Bayesianism may be regarded as a somewhat indeterminate region on a spectrum of views that morph into objective Bayesianism. At one end lies an extreme form of subjective Bayesianism, according to which rational credences are constrained only by the probability calculus (and updating by conditionalization). At the other of the spectrum lies an extreme form of objective Bayesianism, according to which rational probabilities are constrained to the point of uniqueness by one’s evidence—we may call this the Uniqueness Thesis. But both objective Bayesians and subjective Bayesians may adopt less extreme positions, and typically do. For example, Jon Williamson (2010) is an objective Bayesian, but not an extreme one. He adds to the probability calculus the constraints of being calibrated with evidence, and otherwise equivocating between basic outcomes, especially appealing to versions of maximum entropy. As such, his view is a descendant of the classical interpretation and its generalization due to Jaynes. 