Iterated belief change based on epistemic entrenchment

In this paper it is argued that, in order to solve the problem of iterated belief change, both the belief state and its input should be represented as epistemic entrenchment (EE) relations. A belief revision operation is constructed that updates a given EE relation to a new one in light of an evidential EE relation. It is shown that the operation in question satisfies generalized versions of the Gärdenfors revision postulates. The account offered is motivated by Spohn's ordinal conditionalization functions, and can be seen as the Jeffrization of a proposal considered by Rott.I am indebted John G. Bennett and Henry E. Kyburg. jr. for their insightful comments on an earlier draft of this paper. I thank the referees forErkenntnis who, apart from giving extended comments and suggestions, provided me with some hard-to-find relevant material. I also thank Prashanta Bandyopadhyay, Norman Foo, Maurice Pagnucco, Hans Rott and Mary-Anne Williams for their suggestions. The errors that remain are, of course, mine.