JGWeissman comments on Bead Jar Guesses - Less Wrong

17 Post author: Alicorn 04 May 2009 06:59PM

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Comment author: Alicorn 04 May 2009 08:55:47PM *  1 point [-]

You should not guess that the first bead has a 50% chance of being red, because if you do, you can have this conversation:

Omega: What is the probability of the first bead being red as opposed to non-red?

You: Fifty-fifty.

Omega: So you would consider it more than fair if I offered you three dollars if the bead is red, and you paid me a dollar if it was non-red?

You: Sure, I'll take that bet.

Omega: What is the probability of the first bead being blue as opposed to non-blue?

You: Fifty-fifty.

Omega: So you would consider it more than fair if I offered you three dollars if the bead is blue, and you paid me a dollar if it was non-blue?

You: Sure, I'll take that bet.

(...and so on for ten more colors.)

Omega pulls out a red bead. He owes you three dollars, but you owe him eleven dollars. He wins.

Comment author: JGWeissman 04 May 2009 09:12:51PM 1 point [-]

Omega: So you would consider it more than fair if I offered you three dollars if the bead is red, and you paid me a dollar if it was non-red?

Me: No, because you have more information than I do, and the fact that you would offer this bet is evidence that I should use to update my epistemic probabilities.

Comment author: Alicorn 04 May 2009 09:16:51PM 0 points [-]

Well, Omega doesn't really need the money. There's no reason to believe he would balk at offering you a more-than-fair bet.

Comment author: JGWeissman 04 May 2009 09:33:44PM 0 points [-]

Well, in the case of Omega, I would at least suspect that he intends to demonstrate that I am vulnerable to a Dutch book, even though he doesn't need the money.

Comment author: Nominull 04 May 2009 11:28:26PM 7 points [-]

If you meet an Omega, that is pretty good evidence that you are living in a simulation: specifically, you are being simulated inside a philosopher's brain as a thought experiment.