Change rules for hierarchical beliefs

The paper builds a belief hierarchy as a common framework to all uncertainty measures for which an actor is ambiguous about his uncertain beliefs. The belief hierarchy is moreover interpreted by distinguishing physical and psychical worlds, associated to objective and subjective probabilities. Various principles are introduced in order to transform a belief hierarchy, which are applied to establish some links between different contexts of belief change. The numerous belief change rules proposed in the literature can then be associated to specific belief hierarchies and to specific contexts of belief change and epistemic justification of these rules given. The papers brings new and original analysis of the relation between subjective and objective beliefs and on the possibility of learning some generic probabilistic belief despite its resiliency.