trentmkelly/LessWrong-43k huggingface dataset:
Trouble with Bayes Theorem? (The actual math is confusing)
by TheatreAddict — 2011-09-25T04:49:49.990Z

This is probably going to sound utterly ridiculous, but I have a sad confession.

I've read Yudkowsky's post on Bayes' Theorem (http://yudkowsky.net/rational/bayes) five times. I've written down the equation. Tried to formulate an answer.

I still don't understand it. That being said, I've lived my entire life under the false mentality that maths is boring and painful, and it's just recently I've tried to actually understand the concepts I learn in school, and not just temporarily memorize them for the next exam.

Here's the problem, on Yudkowsky's post:

"1% of women at age forty who participate in routine screening have breast cancer. 80% of women with breast cancer will get positive mammographies. 9.6% of women without breast cancer will also get positive mammographies. A woman in this age group had a positive mammography in a routine screening. What is the probability that she actually has breast cancer?"

When Eliezer changes the percentages to real numbers:

"100 out of 10,000 women at age forty who participate in routine screening have breast cancer. 80 of every 100 women with breast cancer will get a positive mammography. 950 out of 9,900 women without breast cancer will also get a positive mammography. If 10,000 women in this age group undergo a routine screening, about what fraction of women with positive mammographies will actually have breast cancer?"

When I see this equation, I can properly make the answer come out to 7.8 percent. I do this, by taking the 80 women, and dividing 80 women by the 80 women plus the 950 women, so 80/80+950 (or 80/1030=.078). So I get 7.8%, which should be the right answer.

But when I try to do the same with percentages, it all gets sort of screwy. I take the 80 percent of women (.8) divided by that same 80 percent (.8) plus 9.5 percent of women without cancer who test postive for it (.095). So I get .8/.8+.095=89%.

I feel like I'm making a really, really stupid error. But I just don't know what it is. >_>
[SEQ RERUN] The "Outside the Box" Box
by MinibearRex — 2011-09-25T03:40:39.165Z

Today's post, The "Outside the Box" Box was originally published on 12 October 2007. A summary (taken from the LW wiki):

When asked to think creatively there's always a cached thought that you can fall into. To be truly creative you must avoid the cached thought. Think something actually new, not something that you heard was the latest innovation. Striving for novelty for novelty's sake is futile, instead you must aim to be optimal. People who strive to discover truth or to invent good designs, may in the course of time attain creativity.

Discuss the post here (rather than in the comments to the original post).
This post is part of the Rerunning the Sequences series, where we'll be 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 Cached Thoughts, 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.
Useful Things Volunteers Can Do Right Now
by lukeprog — 2011-09-24T23:33:14.743Z

Per Kaj's suggestion, I'm posting my list of useful things volunteers can do right now. Without help, most of these things won't occur, because I need to be spending my time writing papers, promoting the Singularity Summit, collaborating with other researchers, improving Singularity Institute's transparency, etc.

Previously, I tried to have volunteers contact me so that I could assign people tasks, but that has become too time consuming (as Eliezer predicted), largely because (in my experience) the odds that a volunteer will actually perform a task given that they've agreed to perform it are very low.

So, I'll post my list here and hope that a few people self-organize to get some of them done. It's worth a shot! My sincere thanks to anyone completes any task on this list.

Translate the Singularity FAQ into other languages, besides English and Italian.

I have about 8 fashion photos each from 3 minicampers, which need to be shown in random order to 5 straight females (in meatspace) who will judge which they prefer. I have the exact experimental design and the photos. Please email me [lukeprog at gmail] if you'd like to do this; it's perfect for somebody social.

Begin to develop a list of AI technology predictions; a step on this path is to create a list of sources for AI technology predictions. We want to eventually be able to write up a report of correlates between predictions and the properties of prediction-makers at the time of their predictions.

Find out how much money the U.S. government/military has spent researching machine ethics (e.g. via Ronald Arkin), and how much of that money was given to whom and for which projects (citing sources along the way).

Work with XiXiDu to interview (via email) more AI researchers about AI risks; see here.

Come up with ways to illustrate the idea of an intelligence explosion or friendly ai with a static graphic or a very short animation; create those graphics or animations if possible.

Make a list of additional media for IntelligenceExplosion.com (e.g. summit videos).

Find a free tool that backs up all your Google Docs, and is available for Mac, Linux, or PC. (thanks Dreaded_Anomaly!)

Research nootropics for rationality, especially for increasing cognitive reflectiveness / need for cognition. Make a list of recent, useful papers on the topic.

Join the Less Wrong Public Goods Team google group and work on, for example, t

...
Meetup : Seattle: Intro to Bayes' Theorem
by SarahNibs — 2011-09-24T21:15:02.606Z

Discussion article for the meetup : Seattle: Intro to Bayes' Theorem

WHEN:
25 September 2011 04:00:00PM (-0700)

WHERE:
Standard location at Robin's house, Seattle, WA

Intro to Bayes' Theorem. We'll go over several ways of intuiting Bayes' Theorem and practice applying it to update on evidence. There will be cheesecake and a whiteboard, and maybe Zendo afterwards.

Join http://groups.google.com/group/lw-seattle for address.

Discussion article for the meetup : Seattle: Intro to Bayes' Theorem
Meetup : Madison
by fiddlemath — 2011-09-24T20:24:22.882Z

Discussion article for the meetup : Madison

WHEN:
27 September 2011 06:00:00PM (-0500)

WHERE:
2100 Winnebago St, Madison WI

Another Madison meetup! This time, we'll do some probability calibration exercises. (These gave me some fairly surprising results; perhaps you'll learn something too!)

Barring real surprises, we'll hold this at Sector67.

If you're in or near Madison, Wisconsin, you should probably join the LessWrong Madison mailing list.

Discussion article for the meetup : Madison
100 transhumanists demanded immortality researh in the center of Moscow
by turchin — 2011-09-24T17:43:32.931Z

More photos here: http://ru-transhuman.livejournal.com/384043.html

This was first legally approved political action of Russian transhumanists. Symbolically it was near Karl Marx monument which is opposite to the Big theater.

Main slogans:

"Stop aging - it is main goal for the state".

"Live 150 years!"

"Immortality!"

"Right to live!"

"We are against death"

The main cognitive bias that played here was that we will be crashed by police. Nothing happened.
[SEQ RERUN] Cached Thoughts
by MinibearRex — 2011-09-24T03:24:13.958Z

Today's post, Cached Thoughts was originally published on 11 October 2007. A summary (taken from the LW wiki):

Brains are slow. They need to cache as much as they can. They store answers to questions, so that no new thought is required to answer. Answers copied from others can end up in your head without you ever examining them closely. This makes you say things that you'd never believe if you thought them through. So examine your cached thoughts! Are they true?

Discuss the post here (rather than in the comments to the original post).
This post is part of the Rerunning the Sequences series, where we'll be 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 Do We Believe Everything We're Told?, 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.
[link] Women in Computer Science, Where to Find More Info?
by magfrump — 2011-09-23T21:11:51.628Z

I recently ran across the following link:

A Campus Champion for Women in Computer Science

Which discusses a new president at Harvey Mudd College, and specifically her work in making the computer science major more accessible to women. This seems neat and interesting except... barely any details are provided whatsoever.

They mention that the introductory computer science course was split into different courses, one of which is taught in Python. Looking at Maria Klowe's webpage on Harvey Mudd she references that these steps were taken in a three part plan, and says "I encourage you to read more" but there are no obvious links on the page to any specifics.

Is anyone from Harvey Mudd that knows more or how to find out more? For example, did the increase in female computer scientists go along with an increase in the size of the program (as is implied) or was there a displacement of male computer scientists? Is the success limited to the one department, or are other engineering and science majors picking up women? I noticed the front page mentioning that Harvey Mudd was recently named the top engineering school in the US, so presumably the gains don't result from "dumbing down" the program, but I'd like to see more information.
The Apparent Reality of Physics
by ec429 — 2011-09-23T20:10:16.577Z

Follow-up to: Syntacticism

I wrote:

The only objects that are real (in a Platonic sense) are formal systems (or rather, syntaxes). That is to say, my ontology is the set of formal systems. (This is not incompatible with the apparent reality of a physical universe).

In my experience, most people default1 to naïve physical realism: the belief that "matter and energy and stuff exist, and they follow the laws of physics". This view has two problems: how do you know stuff exists, and what makes it follow those laws?

To the first - one might point at a rock, and say "Look at that rock; see how it exists at me." But then we are relying on sensory experience; suppose the simulation hypothesis were true, then that sensory experience would be unchanged, but the rock wouldn't really exist, would it? Suppose instead that we are being simulated twice, on two different computers. Does the rock exist twice as much? Suppose that there are actually two copies of the Universe, physically existing. Is there any way this could in principle be distinguished from the case where only one copy exists? No; a manifest physical reality is observationally equivalent to N manifest physical realities, as well as to a single simulation or indeed N simulations. (This remains true if we set N=0.)

So a true description requires that the idea of instantiation should drop out of the model; we need to think in a way that treats all the above cases as identical, that justifiably puts them all in the same bucket. This we can do if we claim that that-which-exists is precisely the mathematical structure defining the physical laws and the index of our particular initial conditions (in a non-relativistic quantum universe that would be the Schrödinger equation and some particular wavefunction). Doing so then solves not only the first problem of naïve physical realism, but the second also, since trivially solutions to those laws must follow those laws.

But then why should we privilege our particular set of physical laws, when that too is just a source of indexical uncertainty? So we conclude that all possible mathematical structures have Platonic existence; there is no little XML tag attached to the mathematics of our own universe that states "this one exists, is physically manifest, is instantiated", and in this view of thi...
Cognitive Style Tends To Predict Religious Conviction (psychcentral.com)
by Incorrect — 2011-09-23T18:28:28.154Z

http://psychcentral.com/news/2011/09/21/cognitive-style-tends-to-predict-religious-conviction/29646.html

Participants who gave intuitive answers to all three problems [that required reflective thinking rather than intuitive] were one and a half times as likely to report they were convinced of God’s existence as those who answered all of the questions correctly.

Importantly, researchers discovered the association between thinking styles and religious beliefs were not tied to the participants’ thinking ability or IQ.

participants who wrote about a successful intuitive experience were more likely to report they were convinced of God’s existence than those who wrote about a successful reflective experience.

I think this is the source but I can't be sure:

http://www.apa.org/pubs/journals/releases/xge-ofp-shenhav.pdf

http://lesswrong.com/lw/7o4/atheism_autism_spectrum/4vbc

Reddit /r/psychology discussion
Silicon Valley AI/Machine Learning study group
by AlexMennen — 2011-09-23T17:18:02.239Z

I am organizing a study group for people in the Silicon Valley area who are taking the Stanford online AI or Machine Learning classes. I posted this to the Tortuga LW meetup google group, but in case there are people here who are interested in such a study group but are not subscribed to it, I'm cross-posting it here. Anyway, I've made a google group for the study group. Please join if you are interested: http://groups.google.com/group/silicon-valley-ai-ml
Weekly LW Meetups: Washington DC, Baltimore, Houston, Seattle, Edinburgh
by FrankAdamek — 2011-09-23T16:37:22.534Z

There are upcoming irregularly scheduled Less Wrong meetups in:

University of Maryland: 16 September 2011 06:00PM
BALTIMORE: Anyone wanna meet up?: 17 September 2011 03:00PM
Houston: 17 September 2011 03:00PM
Seattle Biweekly Meetup: Occam's Razor, Repetition and Time's Up: 19 September 2011 04:00PM
Edinburgh Weekday LW Meetup: 21 September 2011 01:00PM

Cities with regularly scheduled meetups: New York, Berkeley, Mountain View, Cambridge, MA, Toronto, Seattle, San Francisco, Irvine, Austin, Washington, DC, London, Oxford, and West Los Angeles.

If you'd like to talk with other LW-ers face to face, and there is no meetup in your area, consider starting your own meetup; it's easy (more resources here). Check one out, stretch your rationality skills, and have fun!

Despite the handy sidebar of upcoming meetups, we've decided to continue posting an overview of upcoming meetups on the front page every Friday. These will be an attempt to collect information on all the meetups happening in the next weeks. The best way to get your meetup featured is still to use the Add New Meetup feature, but you'll now also have the benefit of having your meetup mentioned in a weekly overview. These overview posts will be moved to the discussion section when the new post goes up.

Please note that for your meetup to appear in the weekly meetups feature, you need to post your meetup before the Friday before your meetup!

If you check Less Wrong irregularly, consider subscribing to one or more city-specific mailing list in order to be notified when an irregular meetup is happening: London, Chicago, Southern California (Los Angeles/Orange County area), St. Louis, Ottawa, Helsinki, Melbourne, Vancouver, Madison, WI.
Particles break light-speed limit?
by Kevin — 2011-09-23T11:00:36.866Z

http://www.nature.com/news/2011/110922/full/news.2011.554.html

http://arxiv.org/abs/1109.4897v1

http://usersguidetotheuniverse.com/?p=2169

http://news.ycombinator.com/item?id=3027056

Ereditato says that he is confident enough in the new result to make it public. The researchers claim to have measured the 730-kilometre trip between CERN and its detector to within 20 centimetres. They can measure the time of the trip to within 10 nanoseconds, and they have seen the effect in more than 16,000 events measured over the past two years. Given all this, they believe the result has a significance of six-sigma — the physicists' way of saying it is certainly correct. The group will present their results tomorrow at CERN, and a preprint of their results will be posted on the physics website ArXiv.org.

At least one other experiment has seen a similar effect before, albeit with a much lower confidence level. In 2007, the Main Injector Neutrino Oscillation Search (MINOS) experiment in Minnesota saw neutrinos from the particle-physics facility Fermilab in Illinois arriving slightly ahead of schedule. At the time, the MINOS team downplayed the result, in part because there was too much uncertainty in the detector's exact position to be sure of its significance, says Jenny Thomas, a spokeswoman for the experiment. Thomas says that MINOS was already planning more accurate follow-up experiments before the latest OPERA result. "I'm hoping that we could get that going and make a measurement in a year or two," she says.

Perhaps the end of the era of the light cone and beginning of the era of the neutrino cone? I'd be curious to see your probability estimates for whether this theory pans out. Or other crackpot hypotheses to explain the results.
Living bias, not thinking bias
by crazy88 — 2011-09-23T08:30:55.493Z

1. Biases, those traits which affect everyone but me

I recently had the opportunity to run an exercise on bias and rationality with a group of (fellow) university students. I wasn't sure it was going to go down well. There's one response that always haunts me when it comes to introducing bias: That's an interesting description of other people but it doesn't describe me.

I can't remember the details (and haven't been able to track them down), but I once read about an experiment on some bias, let's say it was hindsight bias. The research team carried out a standard experiments which showed that the participants were biased as expected. After, they told these participants about hindsight bias. Most of the participants thought this was interesting and probably explained the actions of other people in the experiment but they didn't think it explained their own actions.

So going into the presentation, this is what I was worried about: People thinking these biases were just abstract and didn't affect them.

Then at the end, everyone's comments made it clear that this wasn't the case. They really had realised that these were biases which affected them. The question then is, what led them to reach this conclusion?

2. Living history, living bias

All of the other planets (and the Earth) orbit the Sun. Once upon a time, we didn't believe this: We thought that the these planets (and the Sun) orbited the Earth.

Imagine that you're alive all that time ago, when the balance of evidence has just swung so that it favours the theory that the planets orbit the Sun. However, at the time, you steadfastly insist that they orbit the Earth. Why? Because your father told you it did when you were a child and you always believe things your father told you. Then a friend explains all of the evidence in favour of the theory that the planets orbit the Sun. Eventually, you realise that you were mistaken all along and, at the same time, you realise something else: You realise that it was a mistake not to question a belief just because your father endorsed it.

If you think about history, you learn what beliefs were wrong. If you live history, you learn this and then you also learn what it feels like to mistakenly endorse an incorrect belief. Maybe next time it occurs then, you can avoid making the same error.

In teaching people about biases, I think its best to help students to live biases and not jus...
Syntacticism
by ec429 — 2011-09-23T06:49:40.818Z

I've mentioned in comments a couple of times that I don't consider formal systems to talk about themselves, and that consequently Gödelian problems are irrelevant. So what am I actually on about?

It's generally accepted in mathematical logic that a formal system which embodies Peano Arithmetic (PA) is able to talk about itself, by means of Gödel numberings; statements and proofs within the system can be represented as positive integers, at which point "X is a valid proof in the system" becomes equivalent to an arithmetical statement about #X, the Gödel number representing X. This is then diagonalised to produce the Gödel sentence (roughly, g="There is no proof X such that the last line of X is g", and incompleteness follows. We can also do things like defining □ ("box") as the function from S to "There is a proof X in PA whose last line is S" (intuitively, □S says "S is provable in PA"). This then also lets us define the Löb sentence, and many other interesting things.

But how do we know that □S ⇔ there is a proof of S in PA? Only by applying some meta-theory. And how do we know that statements reached in the meta-theory of the form "thus-and-such is true of PA" are true of PA? Only by applying a meta-meta-theory. There is no a-priori justification for the claim that "A formal system is in principle capable of talking about other formal systems", which claim is used by the proof that PA can talk about itself. (If I remember correctly, to prove that □ does what we think it does, we have to appeal to second-order arithmetic; and how do we know second-order arithmetic applies to PA? Either by invoking third-order arithmetic to analyse second-order arithmetic, or by recourse to an informal system.)

Note also that the above is not a strange loop through the meta-level; we justify our claims about arithmeticn by appeal to arithmeticn+1, which is a separate thing; we never find ourselves back at arithmeticn.

Thus the claim that formal systems can talk about themselves involves ill-founded recursion, what is sometimes called a "skyhook". While it may be a theorem of second-order arithmetic that "the strengthened finite Ramsey theorem is unprovable in PA", one cannot conclude from second-order arithmetic alone that the "PA" in that statement refers to PA. It is however p...
[SEQ RERUN] Do We Believe Everything We're Told?
by MinibearRex — 2011-09-23T03:46:20.415Z

Today's post, Do We Believe Everything We're Told? was originally published on 10 October 2007. A summary (taken from the LW wiki):

Some experiments on priming suggest that mere exposure to a view is enough to get one to passively accept it, at least until it is specifically rejected.

Discuss the post here (rather than in the comments to the original post).
This post is part of the Rerunning the Sequences series, where we'll be 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 Priming and Contamination, 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.