UC Berkeley

This dissertation concerns the interpretation and structure of two intuitive notions: rational credence and confirmation. Probabilistic accounts of rational credence currently enjoy a position of considerable prestige, underwriting significant work not only in philosophy but also in economics and statistics. Confirmation, in contrast, is widely regarded as ill-formed, a misleading misconception akin to phlogiston, witches, or cosmic ether (de Finetti x). The primary project of this dissertation is to undercut the contemporary consensus on both notions by first demonstrating a systemic weakness in probabilistic accounts of rational credence (part I) and then providing a non-probabilistic account of confirmation (part II). Since any adequate account of confirmation is prima facie an adequate account of rational credence, the negative work of part one dovetails with the positive account offered in part two. Confirmation is no misleading misconception, and rational credences are not probability functions.