What is Aumann's Agreement Theorem?

Aumann's Agreement Theorem is a mental model used for better thinking and decision-making.

How do you apply Aumann's Agreement Theorem?

To apply Aumann's Agreement Theorem, identify situations where this framework is relevant, then use it as a lens to evaluate your options and decisions. The model is most useful when combined with other complementary mental models.

What category does Aumann's Agreement Theorem fall under?

Aumann's Agreement Theorem falls under the Psychology & Behavior category of mental models. Other models in this category can be found on the Psychology & Behavior hub page.

Why is Aumann's Agreement Theorem important?

Aumann's Agreement Theorem is important because it provides a structured way to think about problems that would otherwise be approached with intuition alone. Understanding this model helps you avoid common reasoning errors and make better decisions.

Where does Aumann's Agreement Theorem come from?

Aumann's Agreement Theorem is discussed in the tradition of Robert Aumann.

Psychology & Behavior

Aumann's Agreement Theorem

Model #0885Category: Psychology & BehaviorSource: Robert AumannDepth to apply:

3 min read

Contents

1. Core Idea
2. How to See It
3. How to Use It
4. Founders & Leaders
5. Connected Models
6. One Key Quote
7. Summary & Further Reading

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Section 1

Core Idea

Aumann's agreement theorem says that two rational agents who share a common prior and whose posteriors are common knowledge cannot agree to disagree — they must converge to the same belief. In practice, persistent disagreement usually means differing priors, private information, or irrational updating. The core idea: true disagreement has structure; surface it (priors, evidence, process) instead of assuming the other side is irrational.