Abstract: Belief revision and conditional logics are two active areas of research in Artificial Intelligence, Philosophy, and Computer Science. Gardenfors formulated a very natural relation between belief revision systems (ruled by the AGM-postulates) and conditional logics via the so-called Ramsey-Test. However Gardenfors himself proved a Triviality Result according to which such a relation cannot hold for any significant revision system. After Gardenfors’ s negative result the problem of the relations between the two areas has been studied for more than fifteen years, and has stimulated a wide literature.

In this talk we show that the correspondence between conditional logics and belief revision established by Gardenfors’s Ramsey Test can be safely preserved, and the Triviality Result avoided, once we weaken the revision postulates in a very intuitive way. Moreover, we can derive a conditional logic, called BCR, from the revision postulates via the Ramsey-Test.This logic has an axiomatization, a standard selection-function models semantics, and it is decidable. It turns out that there is an isomorphism between belief revision systems and selection function models of BCR. We can therefore claim that the logic BCR provides a logical formalization of belief revision in the (object-) language of conditional logic. This formalization could be a starting point to automatize reasoning about revision.