You're looking at Less Wrong's discussion board. This includes all posts, including those that haven't been promoted to the front page yet. For more information, see About Less Wrong.

ike comments on Probabilities Small Enough To Ignore: An attack on Pascal's Mugging - Less Wrong Discussion

20 Post author: Kaj_Sotala 16 September 2015 10:45AM

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

Comments (176)

You are viewing a single comment's thread.

Comment author: ike 16 September 2015 05:40:15PM 3 points [-]

So, um:

Which axiom does this violate?

Comment author: Sebastian_Hagen 17 September 2015 01:59:27PM *  5 points [-]

Continuity and independence.

Continuity: Consider the scenario where each of the [LMN] bets refer to one (guaranteed) outcome, which we'll also call L, M and N for simplicity.

Let U(L) = 0, U(M) = 1, U(N) = 10**100

For a simple EU maximizer, you can then satisfy continuity by picking p=(1-1/10**100). A PESTI agent, OTOH, may just discard a (1-p) of 1/10**100, which leaves no other options to satisfy it.

The 10**100 value is chosen without loss of generality. For PESTI agents that still track probabilities of this magnitude, increase it until they don't.

Independence: Set p to a number small enough that it's Small Enough To Ignore. At that point, the terms for getting L and M by that probability become zero, and you get equality between both sides.

Comment author: hairyfigment 17 September 2015 12:58:02AM 0 points [-]

Theoretically, that's the question he's asking about Pascal's Mugging, since accepting the mugger's argument would tell you that expected utility never converges. And since we could rephrase the problem in terms of (say) diamond creation for a diamond maximizer, it does look like an issue of probability rather than goals.

Comment author: ike 17 September 2015 01:19:50AM 0 points [-]

Theoretically, that's the question he's asking about Pascal's Mugging, since accepting the mugger's argument would tell you that expected utility never converges

Of course, and the paper cited in http://wiki.lesswrong.com/wiki/Pascal's_mugging makes that argument rigorous.

And since we could rephrase the problem in terms of (say) diamond creation for a diamond maximizer, it does look like an issue of probability rather than goals.

It's a problem of expected utility, not necessarily probability. And I still would like to know which axiom it ends up violating. I suspect Continuity.

Comment author: hairyfigment 17 September 2015 09:43:51AM 0 points [-]

We can replace Continuity with the Archimedean property (or, 'You would accept some chance of a bad outcome from crossing the street.') By my reading, this ELU idea trivially follows Archimedes by ignoring the part of a compound 'lottery' that involves a sufficiently small probability. In which case it would violate Independence, and would do so by treating the two sides as effectively equal when the differing outcomes have small enough probability.