trentmkelly/LessWrong-43k huggingface dataset:
The Present State of Bitcoin
by jimrandomh — 2011-06-21T20:17:13.131Z

Last Sunday, the largest BitCoin exchange, MtGox, was broken into. Reported details are complicated and possibly unreliable, but a fair amount is known. Trading is suspended while the exchange's source code is checked for vulnerabilities. All MtGox accounts are being put through a verification process and mandatory password reset. According to MtGox's support page, a compromised account with 500k coins did a massive sell-off, clearing the order book and driving the price down to 0.01; MtGox has announced that trades around this time will be rolled back. A database of hashed usernames, email addresses, and passwords was leaked on or before June 17 (several hashes from the leaked database were posted on a forum). There is also a report that a cross-site request forgery vulnerability existed, and was being used to steal from users, probably for weeks. There are also highly plausible reports of a SQL injection vulnerability. MtGox has claimed that only $1000 worth of coins were lost, but this is unclear; the large sell-off may have been an attempt to work around the withdrawal rate limit, by making the rate-limiter use an incorrect exchange rate. Analysis of the blockchain seems to suggest that MtGox does still control its coins, or at least a large number of coins.

In the best-case scenario, MtGox reopens for business in a couple days, some traders who would have profited from the sell-off will be angry, and the Bitcoin economy, such as it is, continues as before. In the worst case, MtGox is insolvent, either because they lost more coins as a result of this attack or an earlier attack than they've acknowledged, or because the coming run on the exchange exposes an undisclosed fractional reserve policy.

Meanwhile, TradeHill, the second-largest exchange, is trading at 13.2 USD/BTC with greatly increased volume, compared to 17.5 before this all started. The EFF has stopped accepting BitCoins, in response to these events, and donated their Bitcoin holdings to the Bitcoin faucet. Botnet herders have started hunting for Bitcoin wallets, and allinvain (real name unknown) reported losing 25kBTC from an unencrypted wallet that way.

And I, with a significant amount of both US dollars and Bitcoins frozen on MtGox, am having a very hard time focusing on cell phone app development.
EFF stops accepting Bitcoins
by JoshuaZ — 2011-06-21T15:57:35.441Z

The EFF has stopped accepting Bitcoins primarily out of concern with the possible legal issues. I presume that the EFF has a better understanding of any possible legal risks than organizations like the SIAI. It seems that the SIAI should probably at least for now put a hold on accepting bitcoin donations until these issues are resolved.
Two working memories, one on each side of the brain [link]
by NancyLebovitz — 2011-06-21T13:41:23.627Z

Not a working memory of four, it's really two plus two.

Tl, dr: It's easier to remember four things if you've got two on one side of your visual field and two on the other. Three or four on one side can cause overload errors.

Working memory for other senses hasn't been explored yet on this level.
Fort Collins, Colorado Meetup Wednesday June 22 7pm
by EvelynM — 2011-06-21T00:53:50.957Z

Last week's meeting was a success, with two people in attendance who had read most of Harry Potter and the Methods of Rationality as well as the Sequences.
I'm assigning a 50% chance of a successful meeting this week at the Bean Cycle.
Next week will be the last meetup I organize until August, when I expect to return to weekly meetings.
Evelyn
Melbourne Meetup: Friday 1st July 7pm
by matt — 2011-06-20T18:17:59.335Z

When: Friday 1st July, 19:00 (recurring on the first Friday of each following month)
Where: TrikeApps office, lvl 2, 55 Walsh St, West Melbourne 3003 (http://trikeapps.com/contact)

Directions:
Enter the somewhat unfriendly building, climb the stairs to the top (2 floors), and turn left. If the front door in locked, look for a sign that includes my number, and someone will let you in.
No wheelchair access (sorry).

Discussion: http://groups.google.com/group/melbourne-less-wrong

Note: This post duplicates the fancy new meetup post.
Considering all scenarios when using Bayes' theorem.
by Alexei — 2011-06-20T18:11:34.810Z

Disclaimer: this post is directed at people who, like me, are not Bayesian/probability gurus.

Recently I found an opportunity to use the Bayes' theorem in real life to help myself update in the following situation (presented in gender-neutral way):

Let's say you are wondering if a person is interested in you romantically. And they bought you a drink.
A = they are interested in you.
B = they bought you a drink.
P(A) = 0.3 (Just an assumption.)
P(B) = 0.05 (Approximately 1 out of 20 people, who might be at all interested in you, will buy you a drink for some unknown reason.)
P(B|A) = 0.2 (Approximately 1 out of 5 people, who are interested in you, will buy you a drink for some unknown reason. Though it's more likely they will buy you a drink because they are interested in you.)

These numbers seem valid to me, and I can't see anything that's obviously wrong. But when I actually use Bayes' theorem:
P(A|B) = P(B|A) * P(A) / P(B) = 1.2
Uh-oh! Where did I go wrong? See if you can spot the error before continuing.

Turns out:
P(B|A) = P(A∩B) / P(A) ≤ P(B) / P(A) = 0.1667
BUT
P(B|A) = 0.2 > 0.1667

I've made a mistake in estimating my probabilities, even though it felt intuitive. Yet, I don't immediately see where I went wrong when I look at the original estimates! What's the best way to prevent this kind of mistake?
I feel pretty confident in my estimates of P(A) and P(B|A). However, estimating P(B) is rather difficult because I need to consider many scenarios.

I can compute P(B) more precisely by considering all the scenarios that would lead to B happening (see wiki article):

P(B) = ∑i P(B|Hi) * P(Hi)

Let's do a quick breakdown of everyone who would want to buy you a drink (out of the pool of people who might be at all interested in you):
P(misc. reasons) = 0.05; P(B|misc) = 0.01
P(they are just friendly and buy drinks for everyone they meet) = 0.05; P(B|friendly) = 0.8
P(they want to be friends) = 0.3; P(B|friends) = 0.1
P(they are interested in you) = 0.6; P(B|interested) = P(B|A) = 0.2
So, P(B) = 0.1905
And, P(A|B) = 0.315 (very different from 1.2!)

Once I started thinking about all possible scenarios, I found one I haven't considered explicitly -- some people buy drinks for everyone they meet -- which adds a good amount of probability (0.04) to B happening. (Those types of people are rare, but they WILL buy you a drink.) There are also other interesting assumpt...
existential-risk.org by Nick Bostrom
by XiXiDu — 2011-06-20T17:59:27.958Z

existential-risk.org

(Updated 2011-12-16 due to a comment by Nick Bostrom.)

'Existential Risk FAQ' by Nick Bostrom

(2011) Version 1.0

Short answers to common questions

Link: pdf html

'Existential Risk Prevention as the Most Important Task for Humanity' by Nick Bostrom

(2011) Working paper (revised)

ABSTRACT
Existential risks are those that threaten the entire future of humanity. Many theories of value imply that even relatively small reductions in net existential risk have enormous expected value. Despite their importance, issues surrounding human-extinction risks and related hazards remain poorly understood. In this paper, I clarify the concept of existential risk and develop an improved classification scheme. I discuss the relation between existential risks and basic issues in axiology, and show how existential risk reduction (via the maxipok rule) can serve as a strongly action-guiding principle for utilitarian concerns. I also show how the notion of existential risk suggests a new way of thinking about the ideal of sustainability.

Link: pdf html
The proper use of regret?
by sark — 2011-06-20T10:08:22.305Z

Bryan Caplan in Parenthood as the Trump of All Past Regret explains: whatever tiny alterations he makes to his life before he had his children, would result in him not having the precise children he has today whom he so dearly loves, and therefore he does not regret a thing.

This is seems to me like an entirely wrong use of regret. I think regret is useful when it suggests how you could have done otherwise, when having different such behavioral policy consistently leads to better results in structurally similar situations.

It's not exactly like the mistake of thinking that chaos theory should suggest you pay attention to every little thing in life. There the mistake was to think you could reliably and precisely enough predict how the little things being different leads to outcomes being different. Bryan is thinking about a very specific outcome in his life which he already knows has come to pass. He is counterfactually considering how it would not have been if everything in his past were not exactly as they were.

But given determinism, everything is already decided. This does not rule out free will, but it does suggest a proper use for counterfactuals. According to Vladimir Nesov: The meaning of a thing is how you should be influenced by it (the most succinct expression of LW philosophy imho). According to Gary Drescher: Why should you consider alternatives when making a decision, given that your ultimate actions are already determined? Because counterfactually-speaking if you did not consider such alternatives, you wouldn't have decided the way you did. So the use of counterfactuals, and in particular regret, is for us deciding how to behave. I don't see how Caplan's regret makes use of this.

And of course, there are other aesthetic uses to counterfactuals. Fiction, to take an obvious example. But am I missing something here in thinking that Bryan's regret is quite useless?
Foma: Beliefs that Cause Themselves to be True
by atucker — 2011-06-20T05:13:54.325Z

tl;dr: Sometimes it seems like in order to accomplish something, you need to hold a particular belief. However, the effect of your beliefs on what you accomplish can be screened off from what you actually do.

Also, thank you to Benquo for reading over a rough draft of this and providing very helpful comments.

Foma: Beliefs that Cause Themselves to be True

Live by the foma [harmless untruths] that make you brave and kind and healthy and happy ~ Cat's Cradle

When I was younger, I had formed an idea that there were some beliefs that, when believed, caused themselves to be true. I even had a name picked out for them – foma. These are just a few examples of how I came to think that.

“This is awkward” very often makes things awkward.

Consider walking through a room with a group of people that you don't know very well all talking and laughing. One or two look at you, and you just sort of stare back. “Well,” you think, “this is awkward”.

You stare blankly before letting out an uneasy laugh, and you go on your way. You can feel people watching you walk out the door.

If you just walk through the room without thinking about it at all, its not even emotionally salient enough for you to wonder how it feels.

When I got over my fear of public speaking, it was basically because of a fluke. I decided to do a presentation on the mistakes of Odysseus' crew in character as Odysseus. People then assumed that my shaky arms, legs, and voice were the result of me doing a good portrayal of a shaken Odysseus, rather than my being nervous.

After that, I thought public speaking wasn't so hard as long as I feel comfortable doing it. Taking a few steps to mitigate my physical signs of nervousness (like walking around, or standing behind a podium), I quickly became pretty comfortable doing it.

“I'm not a good public speaker” worsened my public speaking skills, and “I can do this” strengthened them. Areas like self-confidence seem to possibly be foamy.

However on closer reflection, that model is incomplete.

Anticipations Influence Action

Clearly, there are beliefs that don't cause themselves to be true. Foma that work in some instances don't work in others. If I thought I that I was such a great speaker that I could go in front of a group, stare at the ground, and then stutter into some note cards while mumbling offensive ...
DC Meetup: Sunday June 26th, 1:00 PM
by Benquo — 2011-06-20T02:35:33.660Z

Sunday June 26th
Core hours: 1 PM - 3PM
Apartment #1005
3001 Veazey Terrace
Washington, DC 20008

Please note this meetup is now regularly scheduled; you can see the Wiki for details, any changes will be sent out to the mailing list. If you're not on the list, and you want to know about future meetups, you should add your email to the list.

Notes:
Core hours are 1-3, but many people stay around longer than that.

Topic TBA.
See us also at lesswrong-dc@googlegroups.com
[SEQ RERUN] Making Beliefs Pay Rent (in Anticipated Experiences)
by Tyrrell_McAllister — 2011-06-20T00:34:27.940Z

Today's post, Making Beliefs Pay Rent (in Anticipated Experiences), was originally published on 28 July 2007. A summary (taken from the LW wiki):

Not every belief that we have is directly about sensory experience, but beliefs should pay rent in anticipations of experience. For example, if I believe that "Gravity is 9.8 m/s^2" then I should be able to predict where I'll see the second hand on my watch at the time I hear the crash of a bowling ball dropped off a building. On the other hand, if your postmodern English professor says that the famous writer Wulky is a "post-utopian", this may not actually mean anything. The moral is to ask "What experiences do I anticipate?" not "What statements do I believe?"

Discuss the post here (rather than in the comments to the original post).

This post is part of the Rerunning the Sequences series, in which we're going through Eliezer Yudkowsky's old posts in order, so that people who are interested can (re-)read and discuss them. The previous post was Two More Things to Unlearn from School, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.

Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.
Utility Maximization and Complex Values
by XiXiDu — 2011-06-19T16:06:49.106Z

Does expected utility maximization destroy complex values?

An expected utility maximizer does calculate the expected utility of various outcomes of alternative actions. It is precommited to choosing the outcome with the largest expected utility. Consequently it is choosing the action that yields the largest expected utility.

But one unit of utility is not discriminable from another unit of utility. All a utility maximizer can do is to maximize expected utility. What if it turns out that one of its complex values can be much more effectively realized and optimized than its other values, i.e. has the best cost-value ratio? That value might turn out to outweigh all other values.

How can this be countered? One possibility seems to be changing one's utility function and reassign utility in such a way as to outweigh that effect. But this will lead to inconsistency. Another way is to discount the value that threatens to outweigh all others. Which will again lead to inconsistency.

This seems to suggest that subscribing to expected utility maximization means that 1.) you swap your complex values for a certain terminal goal with the highest expected utility 2.) your decision-making is eventually dominated by a narrow set of values that are the easiest to realize and promise the most utility.

Can someone please explain how I am wrong or point me to some digestible explanation? Likewise I would be pleased if someone could tell me what mathematical background is required to understand expected utility maximization formally.

Thank you!
Much-Better-Life Simulator™ - Sales Conversation
by XiXiDu — 2011-06-19T12:44:16.628Z

Related to: A Much Better Life?

Reply to: Why No Wireheading?

The Sales Conversation

Sales girl: Our Much-Better-Life Simulator™ is going to provide the most enjoyable life you could ever experience.

Customer: But it is a simulation, it is fake. I want the real thing, I want to live my real life.

Sales girl: We accounted for all possibilities and determined that the expected utility of your life outside of our Much-Better-Life Simulator™ is dramatically lower.

Customer: You don't know what I value and you can't make me value what I don't want. I told you that I value reality over fiction.

Sales girl: We accounted for that as well! Let me ask you how much utility you assign to one hour of ultimate well-being™, where 'ultimate' means the best possible satisfaction of all desirable bodily sensations a human body and brain is capable of experiencing?

Customer: Hmm, that's a tough question. I am not sure how to assign a certain amount of utility to it.

Sales girl: You say that you value reality more than what you call 'fiction'. But you nonetheless value fiction, right?

Customer: Yes of course, I love fiction. I read science fiction books and watch movies like most humans do.

Sales girl: Then how much more would you value one hour of ultimate well-being™ by other means compared to one hour of ultimate well-being™ that is the result of our Much-Better-Life Simulator™?

Customer: If you ask me like that, I would exchange ten hours in your simulator with one hour of real satisfaction, something that is the result of an actual achievement rather than your fake.

Sales girl: Thank you. Would you agree if I said that for you one hour outside, that is 10 times less satisfying, roughly equals one hour in our simulator?

Customer: Yes, for sure.

Sales girl: Then you should buy our product. Not only is it very unlikely for you to experience even a tenth of ultimate well-being™ that we offer more than a few times per year, but our simulator delivers and allows your brain to experience 20 times more perceptual data than you would be able to experience outside of our simulator. All this at a constant rate while experiencing ultimate well-being™. And we offer free upgrades that are expected to deliver exponential speed-ups and qualitative improvements for the next few decades.

Customer: Thanks, but no thanks. I rather enjoy the real thing....
What are the best news sources to read for *insightful* discussions?
by InquilineKea — 2011-06-19T08:28:25.260Z

I generally agree with Bryan Caplan that news is generally useless:

However, there are some analytical sources of news that are exceptions.

Personally, what I find most stimulating is http://www.mckinseyquarterly.com/home.aspx . http://www.cato-unbound.org/ is also quite stimulating, although it isn't contemporary news. Then on the more non-news-y side, IEEE Spectrum and Communications of the ACM can occasionally be great. And while Scientific American has dumbed down in recent years, the featured articles in Science News (http://www.sciencenews.org/view/feed/type/article) are *amazingly* insightful. Two examples are below:

http://blog.sciencenews.org/view/feature/id/330593/title/Inside_Job http://www.comoogl.sciencenews.org/view/feature/id/74456/title/Healthy_Aging_in_a_Pill

You usually don't even get analyses like these in Science or Nature.

And http://www.newgeography.com/ is surprisingly insightful.

What do people here think of The Atlantic? It's better than other news sources, and I was impressed with it when I was in 8th grade. And some columnists, particularly Reihan Salam, are great (Reihan isn't in the position of supporting *any* politician or party, so that puts him in a position where I don't suspect him of twisting facts [even a little bit] to support his position - something that I do often suspect for people like Ezra Klein and other left-wing pundits). But even The Atlantic does seem to be too much in line with mainstream opinion.

Other than that, I get most of my analysis from Gene Expression and Information Processing. I'm not too much of an economist yet, so I don't really read the economics blogs. FuturePundit/ParaPundit is right on many things, but its blogposts don't contain too much depth in them.
[SEQ RERUN] Two More Things to Unlearn from School
by Tyrrell_McAllister — 2011-06-19T02:46:51.239Z

Today's post, Two More Things to Unlearn from School, was originally published on 12 July 2007. A summary (taken from the LW wiki):

School encourages two bad habits of thought: (1) equating "knowledge" with the ability to parrot back answers that the teacher expects; and (2) assuming that authorities are perfectly reliable. The first happens because students don't have enough time to digest what they learn. The second happens especially in fields like physics because students are so often just handed the right answer.

Discuss the post here (rather than in the comments to the original post).

This post is part of the Rerunning the Sequences series, in which we're going through Eliezer Yudkowsky's old posts in order, so that people who are interested can (re-)read and discuss them. The previous post was Are Your Enemies Innately Evil?, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.

Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.
Why No Wireheading?
by  — 2011-06-18T23:33:39.780Z

I've been thinking about wireheading and the nature of my values. Many people here have defended the importance of external referents or complex desires. My problem is, I can't understand these claims at all.

To clarify, I mean wireheading in the strict "collapsing into orgasmium" sense. A successful implementation would identify all the reward circuitry and directly stimulate it, or do something equivalent. It would essentially be a vastly improved heroin. A good argument for either keeping complex values (e.g. by requiring at least a personal matrix) or external referents (e.g. by showing that a simulation can never suffice) would work for me.

Also, I use "reward" as short-hand for any enjoyable feeling, as "pleasure" tends to be used for a specific one of them, among bliss, excitement and so on, and "it's not about feeling X, but X and Y" is still wireheading after all.

I tried collecting all related arguments I could find. (Roughly sorted from weak to very weak, as I understand them, plus link to example instances. I also searched any literature/other sites I could think of, but didn't find other (not blatantly incoherent) arguments.)

People do not always optimize their actions based on achieving rewards. (People also are horrible at making predictions and great at rationalizing their failures afterwards.)

It is possible to enjoy doing something while wanting to stop or vice versa, do something without enjoying it while wanting to continue. (Seriously? I can't remember ever doing either. What makes you think that the action is thus valid, and you aren't just making mistaken predictions about rewards or are being exploited? Also, Mind Projection Fallacy.)

A wireheaded "me" wouldn't be "me" anymore. (What's this "self" you're talking about? Why does it matter that it's preserved?)

"I don't want it and that's that." (Why? What's this "wanting" you do? How do you know what you "want"? (see end of post))

People, if given a hypothetical offer of being wireheaded, tend to refuse. (The exact result depends heavily on the exact question being asked. There are many biases at work here and we normally know better than to trust the majority intuition, so why should we trust it here?)

Far-mode predictions tend to favor complex, external actions, while near-mode predictions are simpler, more hedonistic. Our true self is the far one, not the near one. (Why? The opposite

...