Comments on: Open Thread http://www.overcomingbias.com/2007/08/open-thread-22.html Overcoming Bias is economist Robin Hanson’s blog, on honesty, signaling, disagreement, forecasting, and the far future. Sat, 11 Feb 2012 23:03:19 +0000 hourly 1 http://wordpress.org/?v=3.1.3 By: steven http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417379 steven Fri, 10 Aug 2007 18:10:02 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417379 Nick, what you're doing feels strongly like cheating, but I can't quite put my finger on how. If you're allowing a 15/16 probability that self-sampling *isn't even applied*, why not do the same thing in many-worlds? Nick, what you’re doing feels strongly like cheating, but I can’t quite put my finger on how. If you’re allowing a 15/16 probability that self-sampling *isn’t even applied*, why not do the same thing in many-worlds?

]]> By: Hopefully Anonymous http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417378 Hopefully Anonymous Fri, 10 Aug 2007 14:32:41 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417378 Nick, I'll put my further replies to this on my anonymous blog, so as not to overrun overcomingbias with it. Nick, I’ll put my further replies to this on my anonymous blog, so as not to overrun overcomingbias with it.

]]> By: Nick Tarleton http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417377 Nick Tarleton Fri, 10 Aug 2007 14:20:24 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417377 <i>Also, it becomes irrational to devote any effort into minimizing existential risk or maximizing personal persistence odds.</i> Not really. What if existential risk is so likely that my most likely subjective continuity is in a world with no other humans? That's no fun. Also, it becomes irrational to devote any effort into minimizing existential risk or maximizing personal persistence odds.

Not really. What if existential risk is so likely that my most likely subjective continuity is in a world with no other humans? That’s no fun.

]]> By: Hopefully Anonymous http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417376 Hopefully Anonymous Fri, 10 Aug 2007 14:07:34 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417376 Combine MWI and a theory of conservation of subjective conscious experience, and it becomes rational to always put desired outcomes over preservation of life. Also, it becomes irrational to devote any effort into minimizing existential risk or maximizing personal persistence odds. One could essentially free ride off of an infinite (or a large number) of other subjective conscious selves. If only we were 100% certain that this particular model was accurate. *sigh* Combine MWI and a theory of conservation of subjective conscious experience, and it becomes rational to always put desired outcomes over preservation of life. Also, it becomes irrational to devote any effort into minimizing existential risk or maximizing personal persistence odds. One could essentially free ride off of an infinite (or a large number) of other subjective conscious selves. If only we were 100% certain that this particular model was accurate. *sigh*

]]> By: Hopefully Anonymous http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417375 Hopefully Anonymous Fri, 10 Aug 2007 13:51:18 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417375 I've been thinking about quantum suicide too. It intuitively feels plausible to anyone who has been around a little while -we can think of all the possibly mortal accidents we avoided. Since quantum immortality is a default option, like the "we're all doomed" default option, I think we should probably focus on the but-for option, namely but for our best efforts to maximize our persistence odds, we're all doomed. Of course, one could perhaps argue that an equally likely scenario is but for our best efforts to maximize our persistence odds, we're all immortal, but if we engage in those exact efforts, we're all doomed, but I think that's probably recursive to the "we're all doomed" default option. So I'd go for the positive but-for option in terms of guiding our actions. I’ve been thinking about quantum suicide too. It intuitively feels plausible to anyone who has been around a little while -we can think of all the possibly mortal accidents we avoided. Since quantum immortality is a default option, like the “we’re all doomed” default option, I think we should probably focus on the but-for option, namely but for our best efforts to maximize our persistence odds, we’re all doomed. Of course, one could perhaps argue that an equally likely scenario is but for our best efforts to maximize our persistence odds, we’re all immortal, but if we engage in those exact efforts, we’re all doomed, but I think that’s probably recursive to the “we’re all doomed” default option. So I’d go for the positive but-for option in terms of guiding our actions.

]]> By: Nick Tarleton http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417374 Nick Tarleton Fri, 10 Aug 2007 13:28:10 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417374 If ~M, there is a 1/16 chance that there is still a living Alice, and therefore that AL occurs. ~AL doesn't mean "Alice observes not existing"; ~AL just means "AL doesn't happen". But you're right, that is confusing. If ~M, there is a 1/16 chance that there is still a living Alice, and therefore that AL occurs. ~AL doesn’t mean “Alice observes not existing”; ~AL just means “AL doesn’t happen”. But you’re right, that is confusing.

]]> By: steven http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417373 steven Fri, 10 Aug 2007 04:16:02 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417373 "P(AL|~M) = 1/16" Where is this coming from? Surely, if there are no living Alices, it is not the case that a randomly chosen living Alice observes not existing; rather, there is then no such thing as a "randomly chosen living Alice" and so your entire framework breaks down. “P(AL|~M) = 1/16″

Where is this coming from? Surely, if there are no living Alices, it is not the case that a randomly chosen living Alice observes not existing; rather, there is then no such thing as a “randomly chosen living Alice” and so your entire framework breaks down.

]]> By: Nick Tarleton http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417372 Nick Tarleton Fri, 10 Aug 2007 02:01:44 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417372 Steven, even if you can't anticipate not experiencing anything, P(AL|M) = 1 because all the Alices observe that Alice is alive. I have a feeling that this paradox indicates a problem in the whole notion of 'anticipated experience', relating to deep misconceptions about personal identity. Steven, even if you can’t anticipate not experiencing anything, P(AL|M) = 1 because all the Alices observe that Alice is alive.

I have a feeling that this paradox indicates a problem in the whole notion of ‘anticipated experience’, relating to deep misconceptions about personal identity.

]]> By: Nick Tarleton http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417371 Nick Tarleton Fri, 10 Aug 2007 01:58:45 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417371 I'll try to shut up and calculate. Say Alice is the victim, Bob is the observer, 4 rounds of the experiment are performed with a 1/2 chance of death on each round, and the prior probability of MWI is 1/2. AL = a randomly chosen living Alice observes 'Alice lives' BL = a randomly chosen living Bob observes 'Alice lives' M = MWI is true, or universe is infinite, or generally all possible events occur P(M) = 1/2 P(AL|M) = 1 P(AL|~M) = 1/16 P(M|AL) = P(AL|M)*P(M)/(P(AL|M)P(M) + P(AL|~M)P(~M)) = (1/2) / (1/2 + 1/16 * 1/2) = (1/2) / (17/32) ~ 0.94 P(BL|M) = 1/16 P(BL|~M) = 1/16 P(M|BL) = P(M) <i>(BL and M are independent)</i> = 1/2 The math seems to work, when cast this way. The living Alices increase P(M), and the Bobs don't change it. Initially I tried to use terms of the form 'some Bob observes that Alice lives', but that became confusing because P(someone observes X|M) = 1 for all X. Fortunately this seems unnecessary. The disagreement seems to come about because Bob can't observe AL. Or can he? If Bob sees Alice alive, doesn't he know this instance observes that Alice lives? Introduce another conditional probability: P(randomly chosen Bob observes AL|M) = 1/16. So, given M, AL is true but the probability of Bob knowing this is only 1/16, same as if ~M; so it can't be evidence for M; so AL being true is evidence to Alice but not to Bob. Huh? I have a feeling I'm missing something really simple. I’ll try to shut up and calculate. Say Alice is the victim, Bob is the observer, 4 rounds of the experiment are performed with a 1/2 chance of death on each round, and the prior probability of MWI is 1/2.

AL = a randomly chosen living Alice observes ‘Alice lives’
BL = a randomly chosen living Bob observes ‘Alice lives’
M = MWI is true, or universe is infinite, or generally all possible events occur

P(M) = 1/2
P(AL|M) = 1
P(AL|~M) = 1/16
P(M|AL) = P(AL|M)*P(M)/(P(AL|M)P(M) + P(AL|~M)P(~M)) = (1/2) / (1/2 + 1/16 * 1/2) = (1/2) / (17/32)
~ 0.94

P(BL|M) = 1/16
P(BL|~M) = 1/16
P(M|BL) = P(M) (BL and M are independent)
= 1/2

The math seems to work, when cast this way. The living Alices increase P(M), and the Bobs don’t change it. Initially I tried to use terms of the form ‘some Bob observes that Alice lives’, but that became confusing because P(someone observes X|M) = 1 for all X. Fortunately this seems unnecessary.

The disagreement seems to come about because Bob can’t observe AL. Or can he? If Bob sees Alice alive, doesn’t he know this instance observes that Alice lives? Introduce another conditional probability: P(randomly chosen Bob observes AL|M) = 1/16. So, given M, AL is true but the probability of Bob knowing this is only 1/16, same as if ~M; so it can’t be evidence for M; so AL being true is evidence to Alice but not to Bob. Huh?

I have a feeling I’m missing something really simple.

]]> By: steven http://www.overcomingbias.com/2007/08/open-thread-22.html#comment-417370 steven Fri, 10 Aug 2007 01:46:59 +0000 http://prod.ob.trike.com.au/2007/08/open-thread-22.html#comment-417370 Quantum Suicide obviously won't work -- if you expect 90% of worlds to be destroyed, you should anticipate with 90% probability that you will stop experiencing anything. If you don't think it's possible to anticipate not experiencing anything, what do you do if you expect 100% of worlds to be destroyed? The Doomsday Argument has both a Bayesian version (Carter, Leslie) and a non-Bayesian version (Gott). Quantum Suicide obviously won’t work — if you expect 90% of worlds to be destroyed, you should anticipate with 90% probability that you will stop experiencing anything. If you don’t think it’s possible to anticipate not experiencing anything, what do you do if you expect 100% of worlds to be destroyed?

The Doomsday Argument has both a Bayesian version (Carter, Leslie) and a non-Bayesian version (Gott).

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