 Subjectivist Bayesians take each unconditional probability function \(P_{\alpha}\) to represent the belief-strengths or confidence-strengths of an ideally rational agent, \(\alpha\). On this understanding ‘\(P_{\alpha}[A] =r\)’ says, “the strength of \(\alpha\)’s belief (or confidence) that A is truth is r”. Subjectivist Bayesians usually tie such belief strengths to how much money (or how many units of utility) the agent would be willing to bet on A turning out to be true. Roughly, the idea is this. Suppose that an ideally rational agent \(\alpha\) would be willing to accept a wager that would yield (no less than) $u if A turns out to be true and would lose him $1 if A turns out to be false. Then, under reasonable assumptions about the agent’s desire money, it can be shown that the agent’s belief strength that A is true should be 