Armok_GoB comments on Maximizing Cost-effectiveness via Critical Inquiry - Less Wrong

20 Post author: HoldenKarnofsky 10 November 2011 07:25PM

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Comment author: Armok_GoB 11 November 2011 08:01:16PM 0 points [-]

This model doesn't seem to work well for extreme values. Most illustratively if gives zero for infinite outcomes. Zero is not a probability.

Comment author: HonoreDB 12 November 2011 01:52:38AM 3 points [-]

Not in my comfort zone here, but surely you have to allow for probabilities of 0 when building any formal mathematical system. P(A|~A) has to be 0 or you can't do algebra. As an agent viewing the system on a meta level, I can't assign a personal probability of 0 to any proof, but within the system it needs to be allowable.

Comment author: dlthomas 12 November 2011 02:08:20AM 2 points [-]

Much discussion of this generally and this point in particular.

I don't know that the results there are necessarily correct, but they are certainly relevant.

Comment author: Armok_GoB 12 November 2011 06:20:49PM 0 points [-]

Thanks for linking those, they are exactly what I were referring to.

Comment author: Jack 13 November 2011 07:00:12PM 0 points [-]

How to deal with deductive uncertainty is an open problem.

Comment author: [deleted] 11 November 2011 08:33:43PM 2 points [-]

Nor is infinity a possible outcome for a charity.

Comment author: Armok_GoB 11 November 2011 10:59:49PM 3 points [-]

It's not a probable outcome, but there literally is no such thing as an impossible outcome.

You donate to the Corrupt Society For Curing Non-existent Diseases in Cute Kittens, the money is used for hallucinogens, the hallucinogens are found by the owners kid, who when high comes up with a physics kitchen experiment which creates an Zeno Machine, and mess around with it randomly. This turns out to simulate an infinite amount of infinitely large cheesecakes, and through a symbolism that you haven't learnt about yet simulated chesecakes have according to your utility function an utility equal to the logarithm of their weight in solar masses.

Comment author: [deleted] 12 November 2011 12:14:38AM 0 points [-]

Who said my utility function was unbounded? (Which, BTW, is the same as my reply to the Pascal's Mugger in the wording “create 3^^^3 units of disutility”.)

Comment author: dlthomas 12 November 2011 12:21:23AM *  3 points [-]

No one - he just said you don't have infinite confidence that your utility function is bounded.

Comment author: Armok_GoB 12 November 2011 06:23:37PM 0 points [-]

Yup. Thanks for handling that one for me.

Comment author: thomblake 11 November 2011 08:10:08PM 0 points [-]

If you're going to have a probability distribution that covers continuous intervals, 0 has to be allowed as a probability.

Comment author: Armok_GoB 11 November 2011 11:01:06PM 0 points [-]

That just looks like a proof you can't have probability distributions over continuous intervals.

Comment author: thomblake 13 November 2011 05:24:44PM *  1 point [-]

0 shouldn't be assigned as a probability if you're going to do Bayesian updates. That doesn't interfere with the necessity of using 0 when assigning probabilities to continuous distributions, as any evidence you have in practice will be at a particular precision.

For example, say the time it takes to complete a task is x. You might assign a probability of 20% that the task is finished between 2.3 and 2.4 seconds, with an even distribution between. Then, the probability that it is exactly 2.35 seconds is 0; however, the measured time might be 2.3500 seconds to the precision of your timing device, whose prior probability would be .02%.

Edit: I need a linter for these comments. Where's the warning "x was declared but never used"?

Comment author: Armok_GoB 13 November 2011 09:08:43PM 0 points [-]

I know that. But any possible interval must be non-zero.

Also, some exact numbers are exceptions, depending on how you measure things: for example, there is a possibility the "task" "takes" EXACTLY 0 seconds, because it was already done. For example, sorting something that was already in the right order. (In some contexts. In other contexts it might be a negative time, or how long it took to check that it really was already done, or something like that)

Infinite utility seems like it might be a similar case.