trentmkelly/LessWrong-43k huggingface dataset:
Dutch Books and Decision Theory: An Introduction to a Long Conversation
by Jack — 2010-12-21T04:55:40.303Z

For a community that endorses Bayesian epistemology we have had surprisingly few discussions about the most famous Bayesian contribution to epistemology: the Dutch Book arguments. In this post I present the arguments, but it is far from clear yet what the right way to interpret them is or even if they prove what they set out to. The Dutch Book arguments attempt to justify the Bayesian approach to science and belief; I will also suggest that any successful Dutch Book defense of Bayesianism cannot be disentangled from decision theory. But mostly this post is to introduce people to the argument and to get people thinking about a solution. The literature is scant enough that it is plausible people here could actually make genuine progress, especially since the problem is related to decision theory.1

Bayesianism fits together. Like a well-tailored jacket it feels comfortable and looks good. It's an appealing, functional aesthetic for those with cultivated epistemic taste. But sleekness is not a rigourous justification and so we should ask: why must the rational agent adopt the axioms of probability as conditions for her degrees of belief? Further, why should agents accept the principle conditionalization as a rule of inference? These are the questions the Dutch Book arguments try to answer.

The arguments begin with an assumption about the connection between degrees of belief and willingness to wager. An agent with degree of belief b in hypothesis h is assumed to be willing to buy wager up to and including $b in a unit wager on h and sell a unit wager on h down to and including $b. For example, if my degree of belief that I can drink ten eggnogs without passing out is .3 I am willing to bet $0.30 on the proposition that I can drink the nog without passing out when the stakes of the bet are $1. Call this the Will-to-wager Assumption. As we will see it is problematic.

The Synchronic Dutch Book Argument

Now consider what happens if my degree of belief that I can drink the eggnog is .3 and my degree of belief that I will pass out before I finish is .75. Given the Will-to-wager assumption my friend can construct a series of wagers that guarantee I will lose money. My friend could offer me a wager on b where I pay $0.30 for $1.00 stakes if I finish the eggnog. He could simultaneously offer me a bet where I pay $0.75 for $1.00 stakes if pass out. Now if I down the eggn...
The Santa deception: how did it affect you?
by Desrtopa — 2010-12-20T22:27:37.348Z

I've long entertained a dubious regard for the practice of lying to children about the existence of Santa Claus. Parents might claim that it serves to make children's lives more magical and exciting, but as a general rule, children are adequately equipped to create fantasies of their own without their parents' intervention. The two reasons I suspect rest at the bottom line are adherence to tradition, and finding it cute to see one's children believing ridiculous things.

Personally, I considered this to be a rather indecent way to treat one's own children, and have sometimes wondered whether a large proportion of conspiracy theorists owe their origins to the realization that practically all the adults in the country really are conspiring to deceive children for no tangible benefit. However, since I began frequenting this site, I've been exposed to the alternate viewpoint that this realization may be good for developing rationalists, because it provides children with the experience of discovering that they hold beliefs which are wrong and absurd, and that they must reject them.

So, how did the Santa deception affect you personally? How do you think your life might have been different without it? If your parents didn't do it to you, what are your impressions on the experience of not being lied to when most other children are?

Also, I promise to upvote anyone who links to an easy to register for community of conspiracy theorists where they would not be averse to being asked the same question.
Solve Psy-Kosh's non-anthropic problem
by cousin_it — 2010-12-20T21:24:01.066Z

The source is here. I'll restate the problem in simpler terms:

You are one of a group of 10 people who care about saving African kids. You will all be put in separate rooms, then I will flip a coin. If the coin comes up heads, a random one of you will be designated as the "decider". If it comes up tails, nine of you will be designated as "deciders". Next, I will tell everyone their status, without telling the status of others. Each decider will be asked to say "yea" or "nay". If the coin came up tails and all nine deciders say "yea", I donate $1000 to VillageReach. If the coin came up heads and the sole decider says "yea", I donate only $100. If all deciders say "nay", I donate $700 regardless of the result of the coin toss. If the deciders disagree, I don't donate anything.

First let's work out what joint strategy you should coordinate on beforehand. If everyone pledges to answer "yea" in case they end up as deciders, you get 0.5*1000 + 0.5*100 = 550 expected donation. Pledging to say "nay" gives 700 for sure, so it's the better strategy.

But consider what happens when you're already in your room, and I tell you that you're a decider, and you don't know how many other deciders there are. This gives you new information you didn't know before - no anthropic funny business, just your regular kind of information - so you should do a Bayesian update: the coin is 90% likely to have come up tails. So saying "yea" gives 0.9*1000 + 0.1*100 = 910 expected donation. This looks more attractive than the 700 for "nay", so you decide to go with "yea" after all.

Only one answer can be correct. Which is it and why?

(No points for saying that UDT or reflective consistency forces the first solution. If that's your answer, you must also find the error in the second one.)
A fun estimation test, is it useful?
by mwengler — 2010-12-20T21:09:37.533Z

So you think its important to be able to estimate how well you are estimating something? Here is a fun test that has been given to plenty of other people.

I highly recommend you take the test before reading any more.

http://www.codinghorror.com/blog/2006/06/how-good-an-estimator-are-you.html

The discussion of this test at the blog it is quoted in is quite interesting, but I recommend you read it after taking the test. Similarly, one might anticipate there will be interesting discussion here on the test and whether it means what we want it to mean and so on.

My great apologies if this has been posted before. I did my bast with google trying to find any trace of this test, but if this has already been done, please let me know and ideally, let me know how I can remove my own duplicate post.

PS: The Southern California meetup 19 Dec 2010 was fantastic, thanks so much JenniferRM for setting it up. This post on my part is an indirect result of what we discussed and a fun game we played while we were there.
What can you do with an Unfriendly AI?
by paulfchristiano — 2010-12-20T20:28:33.665Z

Related to: The Hidden Complexity of Wishes, Cryptographic Boxes for Unfriendly AI, Shut up and Do the Impossible!, AI Boxing in general.

Suppose I give you a powerful genie, who is enormously more intelligent than all human scientists and engineers combined, but who unfortunately hates your guts and is out to destroy human civilization. Fortunately for you, the genie is trapped inside a bottle, equipped with a magical filter. The genie can only interact with the world by speaking to you through the filter, and you can have the filter do whatever you want to the genie's messages before it lets them out.

Of course, you can't hope to gain anything by interacting with such a genie. If it thinks you could trick it into helping you, it can always choose to remain silent. So let's give you some leverage by introducing something the genie cares about more than destroying human society. Suppose that you, as the owner of the bottle, have the power either to free the genie into whatever otherworld it came from (from which he cannot interact with the human world) or to cast the bottle into the fires of Mount Doom, destroying the genie irrevocably. More than anything else, the genie would rather be released than destroyed. Since we are now liable to destroy a lot of genies, lets suppose that we can conjure up new ones at will.

So how well can you use this leverage? The most natural problems to attack are constraint satisfaction problems. In such problems we want to find a message which simultaneously satisfies many automatically verifiable constraints. For example, we may want a message which encodes a proof of the Riemann hypothesis, or a message which encodes a physical theory which accounts for some large body of previously inexplicable experimental evidence.

A first try is to just tell the filter to screen out any message which isn't a solution to the constraint satisfaction problem, and then to precommit to destroying the genie if it doesn't give us a solution (and freeing it as soon as it gives a solution). This has an obvious problem; a proof of the Riemann hypothesis might be valid but still contain an encoding of some terrible threat which would trick us into giving the genie more influence. A program which correctly predicts the motion of galaxies might also coincidentally be a destructi...
Mystical science
by PhilGoetz — 2010-12-20T18:28:35.371Z

Recently I heard an author interviewed on NPR about his book. I can no longer remember the book's name or topic; but I remember that a couple of times during the interview, the author made puzzling categorizations. One of them was approximately: "Throughout history, there are two forces that act on humanity: One bringing us together into large civilizations, and one that breaks down these civilizations, like in the fall of Rome or the Black Death."

The author probably thought he was being scientific in perceiving patterns. But someone who takes the fall of Rome, and the Black Death, and says they are both manifestations of a single force, is doing mystical science. Science says that things with the same underlying causes form a category. Saying that things having the same effects form a category is mysticism.
Estimation is the best we have
by KatjaGrace — 2010-12-20T17:19:04.000Z

This argument seems common to many debates:

‘Proposal P arrogantly assumes that it is possible to measure X, when really X is hard to measure and perhaps even changes depending on other factors. Therefore we shouldn’t do P’.

This could make sense if X wasn’t especially integral to the goal. For instance if the proposal were to measure short distances by triangulation with nearby objects, a reasonable criticism would be that the angles are hard to measure, relative to measuring the distance directly. But this argument is commonly used in situations where optimizing X is the whole point of the activity, or a large part of it.

Criticism of utilitarianism provides a good example. A common argument is that it’s just not possible to tell if you are increasing net utility, or by how much. The critic concludes then that a different moral strategy is better, for instance some sort of intuitive deontology. But if the utilitarian is correct that value is about providing creatures with utility, then the extreme difficulty of doing the associated mathematics perfectly should not warrant abandoning the goal. One should always be better off putting the reduced effort one is willing to contribute into what utilitarian accuracy it buys, rather than throwing it away on a strategy that is more random with regard to the goal.

A CEO would sound ridiculous making this argument to his shareholders. ‘You guys are being ridiculous. It’s just not possible to know which actions will increase the value of the company exactly how much. Why don’t we try to make sure that all of our meetings end on time instead?’

In general, when optimizing X somehow is integral to the goal, the argument must fail. If the point is to make X as close to three as possible for instance, no matter how bad your best estimate is of what X will be under different conditions, you can’t do better by ignoring X all together. If you had a non-estimating-X strategy which you anticipated would do better than your best estimate in getting a good value of X, then you in fact believe yourself to have a better estimating-X strategy.

I have criticized this kind of argument before in the specific realm of valuing of human life, but it seems to apply more widely. Another recent example: people’s attention spans vary between different activities, therefore there i...
Money Circulation in Games
by slimemold4 — 2010-12-20T16:22:01.408Z

I recently heard that they regulate the amount of money circulating in certain MMO games, which seems to me like a far fetched thing. Let us assume that you are a player in a game where you can kill monsters and gold is the currency. Each monster drops a set amount of gold each time you kill it, assuming that the monsters re-spawn, you could continue to pick up the gold dropped by each monster until you had an X amount of money.

Take Runescape for example. In your inventory you have 24 32-bit slots, each slot can hold 2,147,483,647 (or 231-1)gold pieces, but there is no limit to how many stacks of 231-1 gold pieces you can have. The only limit to the amount of gold you can have hear is the size of your banking account, and how many slots it can hold. In a member banking account, there are 516 spaces, which can each hold 2,147,483,647 gold, limiting you to 1,108,101,561,852 gold.

In another game, let us assume that monsters drop not just money, but also items. Let us also assume that there are shops you can sell the items too. If you kill monsters for said items and sell them to said shops, would you place limits on the amount of money said shops had in stock? What would happen when you wanted to sell and the shop had no money left to give you? In Fallout 3 (Which wasn't an MMO game but an XBox 360 game) each shop only had a set amount of "bottlecaps," the currency, and you supplied it to them by buying things from them. If they ran out of gold and you sold your items, then you would just give them away for free. If you were to incorporate this feature into an MMO game, then the result would probably be outrage from many players.

What if a game company were to add a feature which was more lifelike, where all jobs in the world were done by people. If you choose to run a shop, then you buy supplies from a warehouse, which is owned by the game company, and you cannot sell back to them. Assuming you made this game, this would be one way to help regulate money. Another way may be to add banks to a game that could loan you out X amount of money for your business, which you would have to pay back. This seems very realistic though, which may not be what people are looking for in a game (Though if anyone can produce this, I'll buy a copy ^.^).

Is there any real way to regulate currency in a gam...
Copying and Subjective Experience
by lucidfox — 2010-12-20T12:14:22.173Z

The subject of copying people and its effect on personal identity and probability anticipation has been raised and, I think, addressed adequately on Less Wrong.

Still, I'd like to bring up some more thought experiments.

Recently I had a dispute on an IRC channel. I argued that if some hypothetical machine made an exact copy of me, then I would anticipate a 50% probability of jumping into the new body. (I admit that it still feels a little counterintuitive to me, even though this is what I would rationally expect.) After all, they said, the mere fact the copy was created doesn't affect the original.

However, from an outside perspective, Maia1 would see Maia2 being created in front of her eyes, and Maia2 would see the same scene up to the moment of forking, at which point the field of view in front of her eyes would abruptly change to reflect the new location.

Here, it is obvious from both an inside and outside perspective which version has continuity of experience, and thus from a legal standpoint, I think, it would make sense to regard Maia1 as having the same legal identity as the original, and recognize the need to create new documents and records for Maia2 -- even if there is no physical difference.

Suppose, however, that the information was erased. For example, suppose a robot sedated and copied the original me, then dragged Maia1 and Maia2 to randomly chosen rooms, and erased its own memory. At this point, neither either of me, nor anyone else would be able to distinguish between the two. What would you do here from a legal standpoint? (I suppose if it actually came to this, the two of me would agree to arbitrarily designate one as the original by tossing an ordinary coin...)

And one more moment. What is this probability of subjective body-jump actually a probability of? We could set up various Sleeping Beauty-like thought experiments here. Supposing for the sake of argument that I'll live at most a natural human lifespan no matter which year I find myself in, imagine that I make a backup of my current state and ask a machine to restore a copy of me every 200 years. Does this imply that the moment the backup is made -- before I even issue the order, and from an outside perspective, way before any of this copying happens -- I should anticipate subjectively jumping into any given time in the future, and the probability of...
Medieval Ballistics and Experiment
by lucidfox — 2010-12-20T10:13:18.283Z

I'm reading a popular science encyclopedia now, particularly chapters about the history of physics. The chapter goes on to evaluate the development of the concept of kinetic energy, starting with Aristotle's (grossly incorrect) explanation of a flying arrow saying that it's kept in motion by the air behind it, and then continuing to medieval impetus theory. Added: The picture below illustrates the trajectory of a flying cannonball as described by Albert of Saxony.

What struck me immediately was how drastically different from observations its predictions were. The earliest impetus theory predicted that a cannonball's trajectory was an angle: first a slanted straight line until the impetus runs out, then a vertical line of freefall. A later development added an intermediate stage, as seen on the picture to the left. At first the impetus was at full force, and would launch the cannonball in a straight line; then it would gradually give way to freefall and curve until the ball would be falling in a straight line.

While this model is closer to reality than the original prediction, I still cannot help but think... How could they deviate from observations so strongly?

Yes, yes, hindsight bias.

But if you launch a stream of water out of a slanted tube or sleeve, even if you know nothing about paraboles, you can observe that the curve it follows in the air is symmetrical. Balls such as those used for games would visibly not produce curves like depicted.

Perhaps the idea of verifying theories with experiments was only beginning to coalesce at that time, but what kind of possible thought process could lead one to publish theories so grossly out of touch with everyday observations, even those that you see without making any explicit experiments? Did the authors think something along the lines of "Well, reality should behave this way, and if it doesn't, it's its own fault"?
Meta: Cleaning the front page
by Tesseract — 2010-12-20T04:45:32.570Z

All the meetup announcements get promoted, so the front page ends up full of 'em: half of it right now (5/10) is meetup announcements, and with the addition of the quote threads only 30% of the front page is currently 'content'. While meetup announcements are all well and good, it seems counterproductive to have them up there after the meetup date, as is the case with four out of the current five -- it just clutters up the front page even more without providing any benefit.

If post promotion is reversible, it would seem to be a simple step for one of the moderators to depromote each meetup announcement once it's taken place.

(Apologies if this is the wrong place to put an organizational suggestion; I didn't find any obvious better place.)
London Meetup on 2011/1/2
by Alexandros — 2010-12-19T21:01:51.127Z

On Sunday, January 2nd 2011 there will be a meetup the London area. As with previous meetups, the venue is Shakespeare's Head. The meeting will start at 14:00.

In order to keep us organised for 2011, I'm putting together a mailing list for LWers around the London area. If you'd like to be added to the list, please send me your e-mail address via private message.
Christmas
by Richard_Kennaway — 2010-12-19T14:40:26.703Z

What does a rationalist do for Christmas (or whatever analogue is going on around you at this time)? Stay at home and grumble, "Bah, humbug! Stop having-fun-for-bad-reasons, and did you know that Láadan has a single word for that concept?"?

Attempting to light a candle instead, I am giving my teenaged nephew, who was into science but is now into history, "Guns, Germs and Steel", which combines both. Someone else (I haven't decided who) is getting "The Atheist's Guide To Christmas" which has chapters by Richard Dawkins, Ben Goldacre, Simon Singh, and the like.

What are you doing for Christmas?
Sleeping beauty, the doomsday argument and the error of drawing twice.
by  — 2010-12-19T10:06:23.782Z

Suppose there are ten white marbles in an urn. If I draw one of them, what was the probability that I would draw that specific one? If your answer is 1/10 you've just drawn twice. Once to determine the identity of the marble and once to draw it out of the others. If you only draw once, than "that specific one" simply refers to the marble that you drew making the "probability" 1. You cannot follow the identity back after you drew it, because drawing it was the cause for attributing an identity to it. Identity in this sense is in the map not the territory.

This is the same mistake that sleeping beauty makes. She draws once to determine her own identity and once again to draw out of the other "possibilities". The same mistake is behind the doomsday argument. You draw once to determine your own identity and once again to draw yourself out of all the humans. There is no 2/3 probability that Ogh the neanderthal was one of the last 2/3 of all humans. As soon as you say "But I am not Ogh the neanderthal" you are drawing a second time. Otherwise all marbles are white, i.e. all humans are conscious.
Humor
by NancyLebovitz — 2010-12-19T09:27:23.145Z

Reading the recent list of rationality quotes arranged by karma underlines the popularity of funniness, and being funny should probably be included in the pursuit of awesomeness.

My best guesses about characteristics of humor: If there's a word which makes the line funny, put it at the end. Phyllis Diller recommends that the word should end with a hard consonant (t or k).

If you can make a surprising statement extremely concise, there's a reasonable chance it will be funny especially if it includes an insult about an acceptable target.

Quasi-quote from Jim Davis, author of Garfield: "If I can't think of anything funny, I have one of the characters hit another." Any other principles of humor and/or methods for cultivating the ability to be funny?

ETA: The most recent thing that struck me as very funny-- how does it fit into the theories?
The Cambist and Lord Iron: A Fairy Tale of Economics
by Alicorn — 2010-12-19T02:05:22.137Z

Available in PDF here, the short story in question may appeal to LW readers for its approach of viewing more things than are customary in handy economic terms, and is a fine piece of fiction to boot. The moneychanger protagonist gets out of several sticky situations by making desperate efforts, deploying the concepts of markets, revealed preferences, and wealth generation as he goes.