Alicorn comments on Newcomb's Problem and Regret of Rationality - Less Wrong

64 Post author: Eliezer_Yudkowsky 31 January 2008 07:36PM

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Comment author: Alicorn 22 July 2010 06:08:14AM 10 points [-]

You are disposed to take two boxes. Omega can tell. (Perhaps by reading your comment. Heck, I can tell by reading your comment, and I'm not even a superintelligence.) Omega will therefore not put a million dollars in Box B if it sets you a Newcomb's problem, because its decision to do so depends on whether you are disposed to take both boxes or not, and you are.

I am disposed to take one box. Omega can tell. (Perhaps by reading this comment. I bet you can tell by reading my comment, and I also bet that you're not a superintelligence.) Omega will therefore put a million dollars in Box B if it sets me a Newcomb's problem, because its decision to do so depends on whether I am disposed to take both boxes or not, and I'm not.

If we both get pairs of boxes to choose from, I will get a million dollars. You will get a thousand dollars. I will be monetarily better off than you.

But wait! You can fix this. All you have to do is be disposed to take just Box B. You can do this right now; there's no reason to wait until Omega turns up. Omega does not care why you are so disposed, only that you are so disposed. You can mutter to yourself all you like about how silly the problem is; as long as you wander off with just B under your arm, it will tend to be the case that you end the day a millionaire.

Comment author: cousin_it 22 July 2010 06:58:56AM *  6 points [-]

Sometime ago I figured out a refutation of this kind of reasoning in Counterfactual Mugging, and it seems to apply in Newcomb's Problem too. It goes as follows:

Imagine another god, Upsilon, that offers you a similar two-box setup - except to get the $2M in the box B, you must be a one-boxer with regard to Upsilon and a two-boxer with regard to Omega. (Upsilon predicts your counterfactual behavior if you'd met Omega instead.) Now you must choose your dispositions wisely because you can't win money from both gods. The right disposition depends on your priors for encountering Omega or Upsilon, which is a "bead jar guess" because both gods are very improbable. In other words, to win in such problems, you can't just look at each problem individually as it arises - you need to have the correct prior/predisposition over all possible predictors of your actions, before you actually meet any of them. Obtaining such a prior is difficult, so I don't really know what I'm predisposed to do in Newcomb's Problem if I'm faced with it someday.

Comment author: Alicorn 22 July 2010 07:08:04AM 0 points [-]

Something seems off about this, but I'm not sure what.

Comment author: cousin_it 22 July 2010 07:10:30AM *  0 points [-]

I'm pretty sure the logic is correct. I do make silly math mistakes sometimes, but I've tested this one on Vladimir Nesov and he agrees. No comment from Eliezer yet (this scenario was first posted to decision-theory-workshop).

Comment author: Alicorn 22 July 2010 07:11:52AM 1 point [-]

It reminds me vaguely of Pascal's Wager, but my cached responses thereunto are not translating informatively.

Comment author: cousin_it 22 July 2010 07:14:45AM *  1 point [-]

Then I think the original Newcomb's Problem should remind you of Pascal's Wager just as much, and my scenario should be analogous to the refutation thereof. (Thereunto? :-)