HOW NOT TO CHANGE THE THEORY OF THEORY CHANGE - A REPLY TO TENNANT

A number of seminal papers on the logic of belief change by Alchourron , Gardenfors, and Makinson have given rise to what is now known as the AGM paradigm. The present discussion note is a response to Neil Tenna nt's [1994], which aims at a critical appraisal of the AGM approach an d the introduction of an alternative approach. We show that important parts of Tennant's critical remarks are based on misunderstandings or on lack of information. Tn the course of doing this, we attend to some central philosophical issues in the theory of belief change, such as the choice of a representation for belief states and the meaning of an idealized rational agent.