Justifying Conditionalization: Conditionalization Maximizes Expected Epistemic Utility

Abstract

According to Bayesian epistemology, the epistemically rational agent updates her beliefs by conditionalization: that is, her posterior subjective probability after taking account of evidence X, p new , is to be set equal to her prior conditional probability p old ($|X). Bayesians can be challenged to provide a justification for their claim that conditionalization is recommended by rationality-whence the normative force of the injunction to conditionalize?