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Comment author: Multipartite 27 October 2017 02:05:06AM *  0 points [-]

Running through this to check that my wetware handles it consistently.

Paying -100 if asked:

When the coin is flipped, one's probability branch splits into a 0.5 of oneself in the 'simulation' branch, 0.5 in the 'real' branch. For the 0.5 in the real branch, upon awaking a subjective 50% probability that on either of the two possible days, both of which will be woken on. So, 0.5 of the time waking in simulation, 0.25 waking in real 1, 0.25 waking in real 2.

0.5 x (260) + 0.25 x (-100) + 0.25 x (-100) = 80. However, this is the expected cash-balance change over the course of a single choice, and doesn't take into account that Omega is waking you multiple times for the worse choice.

An equation for relating choice made to expected gain/loss at the end of the experiment doesn't ask 'What is my expected loss according to which day in reality I might be waking up in?', but rather only 'What is my expected loss according to which branch of the coin toss I'm in?' 0.5 x (260) + 0.5 x (-100-100) = 30.

Another way of putting it: 0.5 x (260) + 0.25 x (-100(-100)) + 0.25 x (-100(-100)) = 30 (Given that making one choice in a 0.25 branch guarantees the same choice made, separated by a memory-partition; either you've already made the choice and don't remember it, or you're going to make the choice and won't remember this one, for a given choice that the expected gain/loss is being calculated for. The '-100' is the immediate choice that you will remember (or won't remember), the '(-100)' is the partition-separated choice that you don't remember (or will remember).)

--Trying to see what this looks like for an indefinite number of reality wakings: 0.5 * (260) + n x (1/n) x (1/2) x (-100 x n) = 130 - (50 x n), which of the form that might be expected.

(Edit: As with reddit, frustrating that line breaks behave differently in the commenting field and the posted comment.)

Comment author: wedrifid 14 March 2012 03:40:29AM *  0 points [-]

Why does it need to be aim along the planet?

No particular reason. It's just that the arbitrary task of planetary self destruction that Multipartite specified happens to be that of destroying the planet with a bomb on the surface. If you were just trying to destroy the planet then doing so from the surface seems like a terrible idea.

Comment author: Multipartite 14 March 2012 10:49:17PM 0 points [-]

(For thoroughness, noting that the other approach was also wondered about a little earlier. Surface action is an alternative to look at if projectile-launching would definitely be ineffective, but if the projectile approach would in fact be better then there'd no reason not to focus on it instead.)

Comment author: MartinB 04 March 2012 11:40:15PM 3 points [-]

Any kinetic energy an object has, it has to get first. If you compare the size of satellites with their respective rocket it looks difficult to make an object of any reasonable mass get any significant speed. You can trick a bit with swing by maneuvers, but as far as I understand no man made object makes any more than a little sound at the atmosphere while entering. You could however poison the planet with a nice substance.

On the other hand it might be possible to use a man made satellite to deflect a bigger object so that it crashes into earth. But please do not try this on your home.

Comment author: Multipartite 14 March 2012 01:22:05AM 2 points [-]

A fair point. <nods> On the subject of pulling vast quantities of energy from nowhere, does any one country currently possess the knowledge and materials to build a bomb that detonated on the surface could {split the Earth like a grape}/{smash the Earth like an egg}/{dramatic verb the Earth like a metaphorical noun}?

And yes, not something to try in practice with an inhabited location. Perhaps a computer model, at most... actually, there's a thought regarding morbid fascination. I wonder what would be necessary to provide a sufficiently-realistic (uninhabited) physical (computer) simulation of a planet's destruction when the user pulled meteors, momentum, explosives et cetera out of nowhere as it pleased. Even subtle things, like fiddling with orbits and watching the eventual collision and consequences... hm. Presumably/Hopefully someone has already thought of this at some point, and created such a thing. <curiously goes looking>

Comment author: [deleted] 04 March 2012 08:12:16PM *  2 points [-]

Challenge accepted.

(Now all I need to do is to review perturbative orbital dynamics, find a way to launch a spacecraft even though NASA said it would take them two years to do so and it is scheduled to be at closest approach next February, and develop a mechanism for changing the albedo of an asteroid with paint. In space.)

Comment author: Multipartite 04 March 2012 09:17:17PM *  2 points [-]

Not directly related, but an easier question: Do we currently have the technology to launch projectiles out of Earth's atmosphere into a path such that, in a year's time or so, the planet smashes into them from the other direction and sustains significant damage?

(Ignoring questions of targeting specific points, just the question of whether it's possible to arrange that without the projectiles falling into the sun or just following us eternally without being struck or getting caught in our gravity well too soon... hmm, if we could somehow put it into an opposite orbit then it could hit us very strongly, but in terms of energy... hmmm. Ah, and in the first place there's the issue that even that probably wouldn't hit with energy comparable to that of a meteor, though I am not an astrophysicist. In any case, definitely not something to do, but (as noted) morbidly fascinating if it turned out to be fairly easy to pull off. Just the mental image of all the 'AUGH' faces... again, not something one would actually want to do. <clears throat>)

In response to Acausal romance
Comment author: Multipartite 01 March 2012 01:10:25AM *  5 points [-]


In practice, this seems to break down at a specific point: this can be outlined, for instance, with the hypothetical stipulation "...and possesses the technology or similar power to cross universe boundaries and appear visible before me in my room, and will do so in exactly ten seconds.".

As with the fallacy of a certain ontological argument, the imagination/definition of something does not make it existential, and even if a certain concept contains no apparent inherent logical impossibilities that still does not mean that there could/would exist a universe in which it could come to pass.

'All possible worlds' does not mean 'All imaginable worlds'. 'All possible people' does not mean 'All imaginable people'. Past a certain threshold of specificity, one goes from {general types of people who exist almost everywhere, universally speaking} to {specific types of people who only exist in the imaginations of people like you who exist almost everwhere, universally speaking}.

(As a general principle, for instance/incidentally, causality still needs to apply.)

Edit: <amuses self by imagining an immortal near-omniscient mind which would still engage in conversation with the exact replies that a mortal less-than-100-years human writing in a notebook would come up with, rather than say something more insightful/helpful or influenced by more experience/knowledge>

Comment author: lukeprog 28 February 2012 01:15:55AM 4 points [-]

Hey look! I "found" a copy that isn't paywalled.

In response to comment by lukeprog on Acausal romance
Comment author: Multipartite 01 March 2012 12:45:25AM 0 points [-]

(Absent(?) thought after reading: one can imagine someone, through a brain-scanner or similar, controlling a robot remotely. One can utter, through the robot, "I'm not actually here.", where 'here' is where one is doing the uttering through the robot, and 'I' (specifically 'where I am') is the location of one's brain. The distinction between the claim 'I'm not actually here' and 'I'm not actually where I am' is notable. Ahh, the usefulness of technology. For belated communication, the part about intention is indeed significant, as with whether a diary is written in the present tense (time of writing) or in the past tense ('by the time you read this[ I will have]'...).) enjoyed the approach

In response to Longevity Insurance
Comment author: gwern 20 February 2012 03:04:32AM 5 points [-]

You should really call this something else, since longevity insurance is already a thing.

(Don't feel bad; I actually invented them independently before finally learning that it was already a mature industry. Oops.)

In response to comment by gwern on Longevity Insurance
Comment author: Multipartite 21 February 2012 01:36:56AM 0 points [-]

To ask the main question that the first link brings to mind: What prevents a person from paying both a life insurance company and a longevity insurance company (possible the same company) relatively-small amounts of money each in exchange for either a relatively-large payout from the life insurance if the person dies early and a relatively-large payout from the longevity insurance if the person dies late?

To extend, what prevents a hypothetically large number of people to on average create this effect (even if each is disallowed from having both instead of just one or the other) and so creating a guaranteed total loss overall on the part of an insurance company?

<imagines a state in which a payment from company to customer would have to be less than twice the payment from customer to company...>


Comment author: DanielLC 10 February 2012 05:35:45PM 2 points [-]

what exact procedure is taken to increase the log probability by log(2) and return modified percentages?

The simplest way is to use odds ratios instead of log probability. 5% is 1:19. Multiply that by 2:1 and you get 2:19 which corresponds to 9.52%. If it's close to 100%, you get close to half the probability of failure. If it's close to 0%, you get close to double the probability of success.

This can be done with dice by using a virtual d21. You can do that by rolling a higher-numbered die and re-rolling if you pass 21. Since the next die up is d100, you can combine two dice to get d24 or d30 the same way you combine two d10s to get a d100. Alternately, use a computer or a graphing calculator instead of a die, and you can have it give whatever probabilities you want.

Comment author: Multipartite 11 February 2012 09:36:24PM 0 points [-]

Thank you!

In response to comment by gwern on Bayesian RPG system?
Comment author: DanielLC 09 February 2012 12:48:35AM 3 points [-]

That's a 49.995% chance of failure, and a 50.005% chance of success. Also 0.49995 is much closer to 50% than to 49%.

In any case, it should be nowhere near 50%. Increasing the log probability by log(2) would approximately halve the probability of failure if you're very likely to succeed, but it would double the chance of success if you're very likely to fail.

Comment author: Multipartite 10 February 2012 04:10:27PM *  0 points [-]

To answer the earlier question, an alteration which halved the probability of failure would indeed change an exactly-0% probability of success into a 50% probability of success.

If one is choosing between lower increases for higher values, unchanged increases for higher values, and greater increases for higher values, then the first has the advantage of not quickly giving numbers over 100%. I note though that the opposite effect (such as hexing a foe?) would require halving the probability of success instead of doubling the probability of failure.

The effect you describe, whereby a single calculation can give large changes for medium values and small values for extreme values, is of interest to me: starting with (for instance) 5%, 50% and 95%, what exact procedure is taken to increase the log probability by log(2) and return modified percentages?
<unfamiliar with log probabilities, and curious to decrease this unfamiliarity>

Edit: (A minor note that, from a gameplay standpoint, for things intended to have small probabilities one could just have very large failure-chance multipliers and so still have decreasing returns. Things decreed as effectively impossible would not be subject to dice rolling or similar in any case, and so need not be considered at length. In-game explanation for the function observed could be important; if it is desirable that progress begin slow, then speed up, then slow down again, rather than start fast and get progressively slower, then that is also reasonable.)

In response to Bayesian RPG system?
Comment author: Multipartite 08 February 2012 06:06:04PM *  1 point [-]

For what it's worth, I'm reminded of systems which handle modifiers (multiplicatively) according to the chance of failure:

<Google search>


For example, the first 20 INT increases magic accuracy from 80% to

(80% + (100% - 80%) * .01) = 80.2%

not to 81%. Each 20 INT (and 10 WIS) adds 1% of the remaining distance between your current magic accuracy and 100%. It becomes increasingly harder (technically impossible) to reach 100% in any of these derived stats through primary attributes alone, but it can be done with the use of certain items.


A clearer example might be that of a bonus which halves your chance of failure changing 80% success likelihood to 90% success (20% failure to 10% failure), but another bonus of the same type changing that 90% success to 95% success (10% failure to 5% failure). Notable that one could combine the bonus first in calculation to get a quarter of 20% as 5% with no end change.

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