From belief change to preference change

Abstract

There is a huge literature on belief change. In contrast, preference change has been considered only in a few recent papers. There are reasons for that: while there is to some extent a general agreement about the very meaning of belief change, this is definitely not so for preference change. We discuss here the possible meanings of preference change, arguing that we should at least distinguish between four paradigms: preferences evolving after some new fact has been learned, preferences evolving as a result of an evolution of the world, preferences evolving after the rational agent itself evolves, and preferences evolving per se. We then develop in more detail the first of these four paradigms (which we think is the most natural). We give some natural properties that we think preference change should fulfill and define several families of preference change operators, parameterized by a revision function on epistemic states and a semantics for interpreting preferences over formulas.