I haven't studied Aumann's agreement theorem, but according to the Wikipedia article it assumes "Bayesian rationalists with common priors". The article goes on

I haven't studied Aumann's agreement theorem, but according to the Wikipedia article it assumes "Bayesian rationalists with common priors". The article goes on to say that "the assumption of common priors is a rather strong one and may not hold in practice", but according to Robin Hansen this is the case when Bayesians adhere to a certain pre-rationality condition: ". . . Bayesians who agree enough about the origins of their priors must have the same priors" [1]. Will Bayesians ALWAYS agree enough about the origins of their priors? [1] http://link.springer.com/article/10.1007%2Fs11238-006-9004-4#page-1 http://link.springer.com/article/10.1007%2Fs11238-006-9004-4...