brianm comments on Counterfactual Mugging - Less Wrong

52 Post author: Vladimir_Nesov 19 March 2009 06:08AM

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

Comments (257)

You are viewing a single comment's thread. Show more comments above.

Comment author: Lightwave 20 March 2009 07:26:37PM *  3 points [-]

Okay, I agree that this level of precomitting is not necessary. But if the deal is really a one-time offer, then, when presented with the case of the coin already having come up tails, you can no longer ever benefit from being the sort of person who would precommit. Since you will never again be presented with a newcomb-like scenario, then you will have no benefit from being the precommiting type. Therefore you shouldn't give the $100.

If, on the other hand, you still expect that you can encounter some other Omega-like thing which will present you with such a scenario, doesn't this make the deal repeatable, which is not how the question was formulated?

Comment author: brianm 20 March 2009 11:55:30PM 2 points [-]

If you think that through and decide that way, then your precommitting method didn't work. The idea is that you must somehow now prevent your future self from behaving rationally in that situation - if they do, they will perform exactly the thought process you describe. The method of doing so, whether making a public promise (and valuing your spoken word more than $100), hiring a hitman to kill you if you renege or just having the capability of reliably convincing yourself to do so (effectively valuing keeping faith with your self-promise more than $100) doesn't matter so long as it is effective. If merely deciding now is effective, then that is all that's needed.

If you do then decide to take the rational course in the losing coinflip case, it just means you were wrong by definition about your commitment being effective. Luckily in this one case, you found it out in the loss case rather than the win case. Had you won the coin flip, you would have found yourself with nothing though.