 Instead of adding specific belief-postulates to Jeffrey’s theory, as Joyce suggests, one can get the same uniqueness result by enriching the set of prospects. Richard Bradley (1998) has, for instance, shown that if one extends the Boolean algebra in Jeffrey’s theory to indicative conditionals, then a preference relation on the extended domain that satisfies the Bolker-Jeffrey axioms (and some related axioms that specifically apply to conditionals) will be representable as maximising desirability, where the probability function is unique and the desirability function is unique up to a positive linear transformation.