 Jeffrey (1977) provides a simple model of preference change as the consequence of an agent coming to believe a proposition \(A\) to be true. His model incorporates both kinds of belief relevant for doxastic preference change. It is based on the notion of conditional preferences. Jeffrey treats preferences as a relation over propositions, viz. sets of possible worlds. They are represented by a utility function \(\mathbf{U}\) (see section 2), such that: