trentmkelly/LessWrong-43k huggingface dataset:
[link] Why We Reason (psychology blog)
by  — 2012-04-18T11:40:26.079Z

Why We Reason is an excellent psychology blog that has a great deal of subject matter in common with Less Wrong. Some of the topics discussed on the blog include social psychology, judgement and decision making, neuroscience, cognitive biases, and creativity. And there's even a hint of the kind of "cognitive philosophy" practiced on Less Wrong.

The author, Sam McNerney, is blessed with the rare gift of being able to distill psychology topics for a lay audience, and his posts are very lucid.

There's also a handy archive of every post on the site.
If you can't be right, at least be relevant
by Stuart_Armstrong — 2012-04-18T10:17:32.110Z

We've done the motivation, and the warm-ups, and it's now time to get to the meat of this arc: relevance logics. These try to recapture a more intuitive meaning to the material implication, "if... then..." and "→". Consider for instance the following:

"It rains in Spain" → ("Darwin died for our sins" → "It rains in Spain")

("It rains in Spain" and "It doesn't rain in Spain") → "Ravens are the stupidest of birds"

Both of these are perfectly acceptable classical logical theorems. The problem is that there doesn't seem to be any connection between the different components: no logical leap between rain, Darwin or ravens. These are all tautologies, so we could substitute any other propositions in here and it would still be true. In common speech, "if A then B" implies some sort of relevant connection between A and B. Relevance logics attempt to do the same for the formal "→".

Unfortunately, it is easier to motivate relevance logics, and write formal axiomatic systems for them, than it is to pin down exactly what "relevance" means - see the later section on relevance semantics. One oft-mentioned requirement is that the expressions on both sides of "→" share propositional variables. A propositional variable is a basic sentence such as A:"It rains in Spain". Sharing A would mean that the whole expression would be something like:

(blah ∧ blah ∨ A ∧ blah) → (blah ∧ ¬A ∨ blah ∧ blah)

Unfortunately, though this is a necessary condition for relevance, it is not sufficient. Even the hated disjunctive syllogism (the very thing we are trying to avoid) shares variables. In theorem form, it is:

(A ∨ B) ∧ ¬B → A

So let's defer worrying about what relevance means, and look at what relevance is.

Axioms of relevance

When we rejected the disjunctive syllogism, we lost a lot of useful stuff. And not all of that loss was necessary: we can add a bit back without returning to the principle of explosion. Hence the axiom schemas of relevance logics tend to be longer than that of classical logic, as we put in by hand all the useful results we want to keep. "Dialectical logic" is one example of relevance logics; it uses thirteen axiom schemas:

A → A

(A → B) ∧ (B → C) → (A → C)

...
[SEQ RERUN] On Being Decoherent
by MinibearRex — 2012-04-18T05:06:36.445Z

Today's post, On Being Decoherent was originally published on 27 April 2008. A summary (taken from the LW wiki):

When a sensor measures a particle whose amplitude distribution stretches over space - perhaps seeing if the particle is to the left or right of some dividing line - then the standard laws of quantum mechanics call for the sensor+particle system to evolve into a state of (particle left, sensor measures LEFT) + (particle right, sensor measures RIGHT). But when we humans look at the sensor, it only seems to say "LEFT" or "RIGHT", never a mixture like "LIGFT". This, of course, is because we ourselves are made of particles, and subject to the standard quantum laws that imply decoherence. Under standard quantum laws, the final state is (particle left, sensor measures LEFT, human sees "LEFT") + (particle right, sensor measures RIGHT, human sees "RIGHT").

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 Where Experience Confuses Physicists, 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.
Harry Potter and the Methods of Rationality discussion thread, part 16, chapter 85
by FAWS — 2012-04-18T02:30:26.958Z

The next discussion thread is here.

This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 85. The previous thread has long passed 500 comments. Comment in the 15th thread until you read chapter 85.

There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)

The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15.

As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.

Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically:

You do not need to rot13 anything about HP:MoR or the original Harry Potter series unless you are posting insider information from Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).

If there is evidence for X in MOR and/or canon then it’s fine to post about X without rot13, even if you also have heard privately from Eliezer that X is true. But you should not post that “Eliezer said X is true” unless you use rot13.
Visual maps of the historical arguments in the topic, "Can computers think?"
by Logos01 — 2012-04-18T00:55:31.081Z

Located here: http://www.macrovu.com/CCTGeneralInfo.html

Map 1: Can computers think?
Map 2: Can the Turing test determine whether computers can think?
Map 3: Can physical symbol systems think?
Map 4: Can Chinese Rooms think?
Map 5, Part 1: Can connectionist networks think?
Map 5, Part 2: Can computers think in images?
Map 6: Do computers have to be conscious to think?
Map 7: Are thinking computers mathematically possible?

These are available, apparently, for purchase in their full (wall-poster) size.
[META] Alternatives to rot13 and karma sinks
by HonoreDB — 2012-04-17T20:01:45.447Z

rot13 is... (Results)
A quaint internet tradition that I quite enjoy
So annoying
Easy to use because I have Leet Key
Vapbzcerurafvoyr

In November, DanielVarga complained about rot13.com as a way of hiding spoilers, and suggested some specifications for an alternative web service, with an algorithm that can operate on any character. I whipped up two, one using a bitwise not and the other using a password. These have a usability advantage over rot13.com: they automatically generate a decode link, so that people who don't have an add-on such as Leet Key (get Leet Key! or d3coder if you're on Chrome!) on whatever device they're on can still use them. The advantage over using a site like pastebin is that all of the text is encoded in the url, so if makefoil.com is down or you're offline you can still extract it with a bit of work. Both algorithms are in unobfuscated javascript; feel free to host your own version.

Recently, I had the thought of doing a similar thing with polls. This site doesn't have built-in polling functionality, and the project to create it seems to have stalled. People generally solve this by creating a comment for each option, asking people to upvote the comment of their choice, and asking people to downvote another comment to balance the karma. It's elegant as these kludges go, but it's still visually confusing in a comment thread, clogs the "Top Comments" lists, and somehow rarely ends up balancing correctly.

Here's the site I used to create the above poll. Those vote buttons will turn into vote counts once you vote (you may need to refresh). The site outputs poll syntax in two formats: html, which you can use by creating an article and clicking the html button on the top tool bar, or markdown, which is for comments. The markdown display is a little different because the Less Wrong functionality for having an image be a link seems to be broken; the image gets double-encoded or something.

I hope you'll consider using markdownSpoiler or passwordXor when sharing secret info on the next Harry Potter and the Methods of Rationality chapter, and getting input with a makefoil poll.

Notes:

If you use the password version, the spoilered output includes some ascii special characters that LessWrong will automatically wrap in multiple <code> tags. It works, but it's not as pretty as the oth

...
Meetup : Big Berkeley Meetup
by Thausler — 2012-04-17T19:17:11.527Z

Discussion article for the meetup : Big Berkeley Meetup

WHEN:
18 April 2012 06:30:00PM (-0700)

WHERE:
2011 Shattuck Ave, Berkeley, CA

WHEN: 18 April 2012 06:30:00PM WHERE: 2011 Shattuck Ave, Berkeley, CA This will be a joint dinner with the MPHD seminar folks. We'll meet at Biryani House on Shattuck Ave.

Discussion article for the meetup : Big Berkeley Meetup
Question: Being uncertain without worrying?
by fiddlemath — 2012-04-17T13:56:30.274Z

I currently face a pretty major life decision. After some careful analysis, I've concluded that my final decision depends on the answers from some queries that I have made, but whose answers I won't receive for days or perhaps weeks.

In the meantime, I've had great difficulty not obsessing over the pending decision. It warps my priorities and kills my motivation; I'm doing less, with less vigor, and enjoying it less. I've noticed, in the past, that compulsion to worry correlates tightly with depressed mood; given what I know about the mind, I assume that each can cause the other.

In general, this connection seems to make changing one's mind painful, and probably conditions people to hold their ideas with certainty, rather than uncertainty. As such, ways to stave it off should be of major use to this community...

I know some things to do to stave off a depressed mood (e.g. get exercise, eat well, talk to friends, achieve small-but-satisfying goals). I don't know any ways to avoid the compulsion to worry about an uncertain future decision, except, possibly, to notice the worrying and tell myself, verbally, that uncertainty is ok. Which brings me to my

Question: Does anyone know any methods for avoiding fruitless worrying over properly-uncertain facts or actions?
Who's afraid of impossible worlds?
by Stuart_Armstrong — 2012-04-17T12:56:40.358Z

In order to clarify the semantics of paraconsistent and relevance logics, we need to make a detour into impossible worlds - a fruitful detour opening up fun new vistas. Note that this is an intuitive introduction to the subject, and logic is probably the area of mathematics where it is the most dangerous to rely on your intuition; this is no substitute for rigorously going through the formal definitions. With that proviso in mind, let's get cracking.

Possible worlds: the meaning of necessity

Modal logics were developed around the concept of necessity and possibility. They do this with two extra operators: the necessity operator □, and possibility operator ◊. The sentence □A is taken to mean "it is necessary that A" and ◊A means "it is possible that A". The two operators are dual to each other – thus "it is necessary that A" is the same as "it not possible that not-A" (in symbols: □A ↔ ¬◊¬A). A few intuitive axioms then lead to an elegant theory.

There was just one problem: early modal logicians didn't have a clue what they were talking about. They had the syntax, the symbols, the formal rules, but they didn't have the semantics, the models, the meanings of their symbols.

To see the trouble they had, imagine someone tossing a coin and covering it with their hand. Call wH the world in which it comes out heads and wT the world in which it comes out, you guessed it, tails. Now, is the coin necessarily heads? Is it possibly heads?

Intuitively, the answers should be no and yes. But this causes a problem. We may be in the world wH. So if we agree that the coin is not necessarily heads, then it is not necessarily heads even though it is actually heads (forget your Bayescraft here and start thinking like a logician). Similarly, in wT, the coin is in actuality tails yet it is possibly heads.

Saul Kripke found the breakthrough: necessity and possibility are not about individual worlds, but about collections of possible worlds, and relationships between them. In this case, there is a indistinguishability relationship between wT and wH, because we can't (currently) tell them apart.

Because of this relationship, the statement A:"the coin is heads" is possible in both wT and wH. The rule is that a statement is possible in world w if it is true in at lea...
Question about brains and big numbers
by XiXiDu — 2012-04-17T11:57:22.405Z

From time to time I encounter people who claim that our brains are really slow compared to even an average laptop computer and can't process big numbers.

At the risk of revealing my complete lack of knowledge of neural networks and how the brain works, I want to ask if this is actually true?

It took massive amounts of number crunching to create movies like James Cameron's Avatar. Yet I am able to create more realistic and genuine worlds in front of my minds eye, on the fly. I can even simulate other agents. For example, I can easily simulate sexual intercourse between me and another human. Which includes tactile and olfactory information.

I am further able to run real-time egocentric world-simulations to extrapolate and predict the behavior of physical systems and other agents. You can do that too. Having a discussion or playing football are two examples.

Yet any computer can outperform me at simple calculations.

But it seems to me, maybe naively so, that most of my human abilities involve massive amounts of number crunching that no desktop computer could do.

So what's the difference? Can someone point me to some digestible material that I can read up on to dissolve possible confusions I have with respect to my question?
How accurate is the quantum physics sequence?
by Paul Crowley — 2012-04-17T06:54:18.488Z

Prompted by Mitchell Porter, I asked on Physics StackExchange about the accuracy of the physics in the Quantum Physics sequence:

What errors would one learn from Eliezer Yudkowsky's introduction to quantum physics?

Eliezer Yudkowsky wrote an introduction to quantum physics from a strictly realist standpoint. However, he has no qualifications in the subject and it is not his specialty. Does it paint an accurate picture overall? What mistaken ideas about QM might someone who read only this introduction come away with?

I've had some interesting answers so far, including one from a friend that seems to point up a definite error, though AFAICT not a very consequential one: in Configurations and Amplitude, a multiplication factor of i is used for the mirrors where -1 is correct.

Physics StackExchange: What errors would one learn from Eliezer Yudkowsky's introduction to quantum physics?
[SEQ RERUN] Where Experience Confuses Physicists
by MinibearRex — 2012-04-17T03:42:03.342Z

Today's post, Where Experience Confuses Physicists was originally published on 26 April 2008. A summary (taken from the LW wiki):

It then turns out that the entire planet of Ebbore is splitting along a fourth-dimensional thickness, duplicating all the people within it. But why does the apparent chance of "ending up" in one of those worlds, equal the square of the fourth-dimensional thickness? Many mysterious answers are proposed to this question, and one non-mysterious one.

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 Where Physics Meets Experience, 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.
Explanations of mathematical explanation
by KatjaGrace — 2012-04-17T02:08:04.000Z

I recently read Mathematical Explanation [gated], by Mark Steiner (1978). My summary follows, and my commentary follows that. I am aware that others have written things since 1978 on this topic, but I don’t have time to read them right now.

***

We seem to think there is a distinction between explaining a mathematical fact and merely demonstrating it to be the case. We have proofs that do both things, and perhaps a sliding scale of explanatoriness between them. One big question then is what makes a proof actually explain the thing it proves? Or at least what makes it seem that way to us?

One suggestion has been the level of generality or abstractness. Perhaps if we show a particular fact follows from some much bigger theory, the fact feels more explained. But then consider this fact:

1+2+3+…+n = n(n+1)/2

There is an inductive proof of this:

S(1) = 1(1+1)/2 = 1

S(n+1) = S(n) + (n + 1) = n(n+1)/2 + 2(n+1)/2 = (n + 1)(n+2)/2

This is not taken to be very explanatory. Whereas this is:

O O O O O

O O O O O

O O O O O

O O O O O

[the black circles make a triangle of 1+2+3+4. Any such triangle can be made into a rectangle of area n x (n+1) with another identical triangle. So the triangle is half of n(n+1).]

It seems the latter is if anything less general, yet it seems a much better explanation (I remember learning it this way as a preteen in book about fun math magic). There are other examples.

This case and others, suggest being able to visualize a proof is key to its seeming to be an explanation. Steiner discards this immediately as being too subjective, and claims there are also counterexamples.

He also quickly dismisses a third hypothesis that others have forwarded: that a proof is explanatory if it could have been used to discover the fact, rather than just to verify it. His counterexample is the Eulerian identity, which I shan’t go into here. I take it this hypothesis isn’t very plausible anyway, since often we discover a fact first then hope to explain it better.

Steiner offers his own theory: that a proof is explanatory if it makes use of a ‘characterizing property’ of an entity that is mentioned in the theorem. ‘Characterizing properties’ characterize an entity relative to other entities in some similar family. For instance, 18 might be characterized as 2*3*3, since other numbers don’t have that property. 18 might also be characterized as being one more than 17,...
The Blue School
by Voltairina — 2012-04-16T18:15:53.428Z

The Blue School appears to be a neuroscience driven playgroup for children to learn about their own neuroanatomy and emotional self-regulation and are given language to describe their feelings...

"So young children at the Blue School learn about what has been called “the amygdala hijack” — what happens to their brains when they flip out. Teachers try to get children into a “toward state,” in which they are open to new ideas. Periods of reflection are built into the day for students and teachers alike, because reflection helps executive function — the ability to process information in an orderly way, focus on tasks and exhibit self-control. Last year, the curriculum guide was amended to include the term “meta-cognition”: the ability to think about thinking.

“Having language for these mental experiences gives children more chances to regulate their emotions,” said David Rock, who is a member of the Blue School’s board and a founder of NeuroLeadership Institute, a global research group dedicated to understanding the brain science of leadership.

That language is then filtered through a 6-year-old’s brain.

Miles, one of the kindergartners drawing their emotions, showed off his picture and described the battle it depicted between happiness and anger this way: “The happy fights angry, but angry gets blocked by the force field and can’t get out.” Happiness could escape through his mouth, Miles explained. But anger got trapped, turning into sadness.

With ample research showing that negative emotions impede learning while positive emotions broaden children’s attention and their ability to acquire and retain information, strategies for regulating emotions are getting more emphasis in progressive schools across the country."
Using People's Irrationality To Do Good by Leslie John
by Utopiah — 2012-04-16T18:10:35.486Z

http://www.youtube.com/watch?v=MyRPL-QoZG8

Official description:

Identifying effective obesity treatment is both a clinical challenge and a public health priority. Can monetary incentives stimulate weight loss? Leslie John presents a study that examines different economic incentives for weight loss during a 16 week intervention.
Leslie John presented at the "The Science of Getting People to Do Good" research briefing at the Stanford Graduate School of Business, co-sponsored by the Center for Social Innovation.
Related Links:
http://csi.gsb.stanford.edu/special-event-science-getting-people-do-good
http://drfd.hbs.edu/fit/public/facultyInfo.do?facInfo=ovr&facId=589473

Simply sharing this resource here as it could start interesting discussions on moral and rationality.
Meetup : First Copenhagen meetup
by Nisan — 2012-04-16T15:53:37.975Z

Discussion article for the meetup : First Copenhagen meetup

WHEN:
29 April 2012 05:00:00PM (+0200)

WHERE:
Frederiksborggade 7, 1360 København, Denmark

Let's see how many Less Wrong readers there are in and around Copenhagen! The location for this meetup is the Barresso Coffee at Frederiksborggade 7, 1360 København. That's near the Nørreport metro station. Let's meet at 17:00. (The coffeehouse closes at 19:00.)

I will be there with a sign that says "Less Wrong". In addition to getting to know each other and talking about interesting things, we can have a discussion centered around the prompt "Describe a time when you felt belonging in a community." I look forward to meeting you!

Discussion article for the meetup : First Copenhagen meetup