Psy-Kosh comments on The Aumann's agreement theorem game (guess 2/3 of the average) - Less Wrong

15 [deleted] 09 June 2009 07:29AM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (149)

You are viewing a single comment's thread.

Comment author: Psy-Kosh 09 June 2009 07:38:46AM 0 points [-]

The Aumann agreement theorem, as I understand it, has to do with what happens when rational agents share all their data with each other.

But still, sending my guess.

Comment author: conchis 09 June 2009 11:34:10AM 2 points [-]

I assume that the point is to test the assumption of common knowledge of rationality (which is crucial to Aumann agreement) rather than testing Aumann agreement directly.

Comment author: [deleted] 10 June 2009 01:33:20AM 1 point [-]

The Aumann agreement theorem has to do with what happens when rational agents share a single probability estimate with each other. They need not share their evidence.

Comment author: Psy-Kosh 13 June 2009 06:15:06AM 0 points [-]

Ah, okay, thanks.

Comment author: [deleted] 10 June 2009 07:25:14PM 0 points [-]

...and to whoever voted me and Robin Hanson down (not that they're necessarily the same person), if you think that we're wrong, please say so, so that our disagreement will be resolved through reasoning, not through brute force.

Comment author: JGWeissman 10 June 2009 07:44:57PM 1 point [-]

It wasn't me, but I think that your response is much better than Robin's, because instead of an unsupported flat out contradiction, you described what the theorem is actually about.

As near as I can tell, what the theorem says is that, provided two people have common knowledge (meaning not only that they know, but also that they know the other one knows, and that the other one knows they know, ad infinitum) that they are Bayesian rationalists with the same priors, that if they both give each other probability estimates for an event, and they don't then change their estimates, then their estimates must have been equal. It doesn't actually say how they should come to an agreement if their initial estimates differ, or even that they will.

Comment author: pengvado 13 June 2009 10:20:32AM *  2 points [-]

Indeed, Aumann's original proof was not constructive. However, it has since been proved that the protocol "state your current posterior, update on the other agent's statement, repeat" will converge to agreement.

Comment author: RobinHanson 09 June 2009 11:06:23PM 0 points [-]

No, that is not what the agreement theorem is about.