 Belief Revision has traditionally restricted attention to single-agent, “ontic” belief change: the beliefs in question all belong to a single agent, and the beliefs themselves concern only the “facts” of the world and not, in particular, higher-order beliefs (i.e., beliefs about beliefs). Further, as a result of the Success postulate, the incoming formula F that brings about the belief change is assumed to be completely trustworthy: the agent accepts without question the incoming information F and incorporates it into her set of beliefs as per the belief change process. 