We propose and axiomatically characterize dynamically consistent update rules for decision making under ambiguity … of preferences over acts, to be able to reconcile typical behavior in the face of ambiguity (as exemplified by Ellsberg …’s paradox) with dynamic consistency for all non-null events. Updating takes the form of applying Bayes’ rule to subsets of the …

, the decisions differ no matter how long the communication lasts. Such persistent disagreements are precluded in Bayesian … frameworks endowed with a common prior. When communication is private and nobody is excluded from it, we show that ambiguity …-free communication is a necessary and sufficient condition for a consensus to emerge. However, when communication is public, ambiguity …