  Against Jeffrey's definition of expected utility, Spohn (1977) and Levi (1991) object that a decision-maker should not assign probabilities to the very acts under deliberation: when freely deciding whether to perform an act \(A\), you shouldn't take into account your beliefs about whether you will perform \(A\).  If Spohn and Levi are right, then Jeffrey's ratio is undefined (since its denominator is undefined).