# Wei_Dai comments on Torture vs. Dust vs. the Presumptuous Philosopher: Anthropic Reasoning in UDT - Less Wrong

16 03 September 2009 11:04PM

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Comment author: 05 September 2009 03:56:03PM 1 point [-]

I don't get this either, sorry. Can you give an example where "You don't "update" on your own mathematical computations either" makes sense?

Here's how I see CM-with-math-coin goes in more detail. I think we should ask the question, suppose you think that Omega may come in a moment to CM you using the n-th bit of pi, what would you prefer your future self to do, assuming that you can compute n-th bit of pi, either now or later? If you can compute it now, clearly you'd prefer your future self to not give \$100 to Omega if the bit is 0.

What if you can't compute it now, but you can compute it later? In that case, you'd prefer your future self to not give \$100 to Omega if it computes that the bit is 0. Because suppose the bit is 1, then Omega will simulate/predict your future self, and the simulated self will compute that the bit is 1 and give \$100 to Omega, so Omega will reward you. And if the bit is 0, then Omega will not get \$100 from you.

Since by "updating" on your own computation, you win both ways, I don't see why you shouldn't do it.

Comment author: 05 September 2009 07:52:45PM *  1 point [-]

(I converted this comment to a top-level post. See Counterfactual Mugging and Logical Uncertainty. A little bit is left here in the original notation, as a reply.)

I assume you recast the problem this way: if the n-th bit of pi is 1, then Omega maybe gives you \$10000, and if the bit is 0, then Omega asks for the \$100.

If the bit is 1, Omega's simulation of you can't conclude that the bit is 0, because the bit is 1. Omega doesn't compute what you'll predict in reality, it computes what you would do if the bit was 0 (which it isn't, in reality, in this case where it isn't). And as you suggested, you decline to give away the \$100 if the bit is 0, thus Omega's simulation of counterfactual will say that you wouldn't oblige, and you won't get the \$10000.