Gustavo Lacerda

Robert Aumann, of "you can't agree to disagree" fame, shares the Nobel this year with Thomas Schelling. via Marginal Revolution

from Tyler Cowen, Robin Hanson - Are Disagreements Honest?

... according to well-known theory, such honest disagreement is impossible. Robert Aumann (1976) first developed general results about the irrationality of “agreeing to disagree.” He showed that if two or more Bayesians would believe the same thing given the same information (i.e., have “common priors”), and if they are mutually aware of each other's opinions (i.e., have “common knowledge”), then those individuals cannot knowingly disagree. Merely knowing someone else’s opinion provides a powerful summary of everything that person knows, powerful enough to eliminate any differences of opinion due to differing information.