orthonormal comments on Pascal's Muggle: Infinitesimal Priors and Strong Evidence - Less Wrong

43 Post author: Eliezer_Yudkowsky 08 May 2013 12:43AM

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

Comments (404)

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

Comment author: Jiro 06 May 2013 01:05:14AM *  4 points [-]

If someone suggests to me that they have the ability to save 3^^^3 lives, and I assign this a 1/3^^^3 probability, and then they open a gap in the sky at billions to one odds, I would conclude that it is still extremely unlikely that they can save 3^^^3 lives. However, it is possible that their original statement is false and yet it would be worth giving them five dollars because they would save a billion lives. Of course, this would require further assumptions on whether people are likely to do things that they have not said they would do, but are weaker versions of things they did say they would do but are not capable of.

Also, I would assign lower probabilities when they claim they could save more people, for reasons that have nothing to do with complexity. For instance, "the more powerful a being is, the less likely he would be interested in five dollars" or :"a fraudster would wish to specify a large number to increase the chance that his fraud succeeds when used on ordinary utility maximizers, so the larger the number, the greater the comparative likelihood that the person is fraudulent".

the phrase "Pascal's Mugging" has been completely bastardized to refer to an emotional feeling of being mugged that some people apparently get when a high-stakes charitable proposition is presented to them, regardless of whether it's supposed to have a low probability.

1) Sometimes what you may actually be seeing is disagreement on whether the hypothesis has a low probability.

2) Some of the arguments against Pascal's Wager and Pascal's Mugging don't depend on the probability. For instance, Pascal's Wager has the "worshipping the wrong god" problem--what if there's a god who prefers that he not be worshipped and damns worshippers to Hell? Even if there's a 99% chance of a god existing, this is still a legitimate objection (unless you want to say there's a 99% chance specifically of one type of god).

3) In some cases, it may be technically true that there is no low probability involved but there may be some other small number that the size of the benefit is multiplied by. For instance, most people discount events that happen far in the future. A highly beneficial event that happens far in the future would have the benefit multiplied by a very small number when considering discounting.

Of course in cases 2 and 3 that is not technically Pascal's mugging by the original definition, but I would suggest the definition should be extended to include such cases. Even if not, they should at least be called something that acknowledges the similarity, like "Pascal-like muggings".

Comment author: orthonormal 06 May 2013 03:57:24AM *  2 points [-]

2) Some of the arguments against Pascal's Wager and Pascal's Mugging don't depend on the probability. For instance, Pascal's Wager has the "worshipping the wrong god" problem--what if there's a god who prefers that he not be worshipped and damns worshippers to Hell? Even if there's a 99% chance of a god existing, this is still a legitimate objection (unless you want to say there's a 99% chance specifically of one type of god).

That argument is isomorphic to the one discussed in the post here:

"Hmm..." she says. "I hadn't thought of that. But what if these equations are right, and yet somehow, everything I do is exactly balanced, down to the googolth decimal point or so, with respect to how it impacts the chance of modern-day Earth participating in a chain of events that leads to creating an intergalactic civilization?"

"How would that work?" you say. "There's only seven billion people on today's Earth - there's probably been only a hundred billion people who ever existed total, or will exist before we go through the intelligence explosion or whatever - so even before analyzing your exact position, it seems like your leverage on future affairs couldn't reasonably be less than a one in ten trillion part of the future or so."

Essentially, it's hard to argue that the probabilities you assign should be balanced so exactly, and thus (if you're an altruist) Pascal's Wager exhorts you either to devote your entire existence to proselytizing for some god, or proselytizing for atheism, depending on which type of deity seems to you to have the slightest edge in probability (maybe with some weighting for the awesomeness of their heavens and awfulness of their hells).

So that's why you still need a mathematical/epistemic/decision-theoretic reason to reject Pascal's Wager and Mugger.

Comment author: private_messaging 06 May 2013 04:54:04AM 2 points [-]

What you have is a divergent sum whose sign will depend to the order of summation, so maybe some sort of re-normalization can be applied to make it balance itself out in absence of evidence.

Comment author: endoself 06 May 2013 11:40:44PM *  4 points [-]

Actually, there is no order of summation in which the sum will converge, since the terms get arbitrary large. The theorem you are thinking of applies to conditionally convergent series, not all divergent series.

Comment author: private_messaging 08 May 2013 02:59:59PM *  2 points [-]

Strictly speaking, you don't always need the sums to converge. To choose between two actions you merely need the sign of difference between utilities of two actions, which you can represent with divergent sum. The issue is that it is not clear how to order such sum or if it's sign is even meaningful in any way.

Comment author: orthonormal 06 May 2013 02:30:16PM 0 points [-]

Without discussing the merits of your proposal, this is something that clearly falls under "mathematical/epistemic/decision-theoretic reason to reject Pascal's Wager and Mugger", so I don't understand why you left that comment here.