Posts

Cheat codes 2010-12-01T21:19:39.547Z
Sam Harris' surprisingly modest proposal 2010-10-06T00:46:05.838Z
Five-minute rationality techniques 2010-08-10T02:24:48.246Z

Comments

Comment by sketerpot on Technocracy and the Space Age · 2022-08-02T20:40:13.768Z · LW · GW

And also computationally impossible for a space endeavor of any size until the late 90’s (citation needed here and would love to hear from someone with experience).

I looked into it and, yes, this looks basically correct with a caveat: it's computationally very expensive to get those first stages to land on their own at a convenient, precisely chosen location. We've been doing propulsive landings for decades with e.g. the Apollo moon landers and the Viking Mars probes, the latter of which had to be fully autonomous because of speed-of-light delays. Landing a big long rocket is a bit harder because of its somewhat unwieldy shape, but inverted pendulum control problems are definitely not a new thing.

So where does it get computationally hard? There are two parts to it. The first part is computing a trajectory and a flight plan -- when you should fire up the engines, which way you should be pointing them, what the aerodynamic control surfaces should be doing -- which should get you to the desired landing location. This is a tricky optimization problem, with a bunch of annoyingly non-convex control constraints. The second hard part, and the reason you can't just precompute the flight plan on a really big computer before launching the rocket, is that you need to adjust the plan in realtime. There will inevitably be unpredictable deviations from the original plan caused by things like wind or variation in atmospheric density. If you don't compensate for them, those deviations will add up; the Curiosity Mars rover, for example, was a big improvement over its predecessors because its predicted landing zone was an ellipse that only measured 20 km by 7 km.

The algorithm (PDF) that I hear SpaceX is using does require some pretty serious processing power if you're going to be recomputing your entire flight plan several times per second.  A version suitable for realtime use wasn't flight-tested until the early 2010s.

Comment by sketerpot on Lies Told To Children · 2022-04-16T21:15:24.585Z · LW · GW

There's also variation in the amount of children's television watched by people in the test population. The protagonist mentions seeing "less children's television than most children in our age cohort", and it's a safe bet that this was tracked as part of the data set.

Comment by sketerpot on Lies Told To Children · 2022-04-16T21:13:25.316Z · LW · GW

Not just genetic tendencies; it was also meant to look at shared environment, like the TV shows subtly but thoroughly pushing a certain worldview, and the words from teachers saying it explicitly. From the story: they wanted "to find out how well we were doing environment-wise and heredity-wise on people's kindness and resistance to conformity-pushed cruelty".

Comment by sketerpot on Don't Be Afraid of Asking Personally Important Questions of Less Wrong · 2015-04-05T19:20:29.679Z · LW · GW

Ah. That web site throws out too many claims to investigate fully -- who has the time? -- but if you google around for a sampling of them you'll notice that they tend to crumble under scrutiny. The sections mentioning quantum mechanics are especially blatant: they're gibberish, total incoherent misuse of terminology.

EDIT: There's a sequence of articles called Mysterious Answers to Mysterious Questions which is relevant here. One that applies in particular is Fake Explanations, which could be summarized as "If you are equally good at explaining any outcome, you have zero knowledge." When people talk about "etheric worlds on different frequencies", or "energy vortices swirling faster than the speed of light on the earth plane", what does this predict? What, concretely, does it mean? If it can explain anything, then it predicts nothing.

Comment by sketerpot on Don't Be Afraid of Asking Personally Important Questions of Less Wrong · 2015-04-05T18:29:15.616Z · LW · GW

Did you mean to post a link here? I'm not seeing one.

Comment by sketerpot on Stupid Questions March 2015 · 2015-03-08T05:45:34.957Z · LW · GW

If you were to try and search the space of all possible inputs for MD5, you'd quickly(ish) find an input that collided with the Obama Werewolf input, but it'd be garbage.

Really? Last I checked, the best known preimage attack against MD5 was too slow to be practical. Finding collisions is drastically easier, though I don't know any method for doing it with arbitrary plain-text English sentences.

Comment by sketerpot on Harry Potter and the Methods of Rationality discussion thread, February 2015, chapter 108 · 2015-02-22T21:42:56.504Z · LW · GW

Not just modern sexual attitudes, but specifically the sexual attitudes you see in the Harry Potter fanfiction community. And I'm sure it was meant to be jarring. Magical Britain's culture is subtly but deeply different from that of the muggle country that shares its borders; it would be profoundly weird if there were no surprises, no culture shock.

Comment by sketerpot on Harry Potter and the Methods of Rationality discussion thread, February 2015, chapter 104 · 2015-02-16T07:06:42.156Z · LW · GW

He's the Super Hufflepuff! He's taking all the electives, which is physically impossible without a Time Turner! He was mentioned right before Harry started making thorough off-screen preparations, and then conspicuously forgotten for the rest of the chapter! Dramatic logic dictates that he's got to show up at some point, probably in some way that involves time travel.

... Unless the whole thing was a throwaway joke about how useless Cedric was in Goblet of Fire, in which case yeah, I guess it was pretty funny.

Comment by sketerpot on Harry Potter and the Methods of Rationality discussion thread, February 2015, chapter 104 · 2015-02-16T06:57:10.008Z · LW · GW

An alternate interpretation is that Voldemort was strengthening a few of the spells that Sprout cast, as well as the spell that Tonks used to win the battle, and this use of his own magic was what caused Harry's doom-sense to tingle. If that's the case, then there would be none of his magic on the troll.

Comment by sketerpot on The morality of disclosing salary requirements · 2015-02-11T00:55:29.058Z · LW · GW

Other useful dummy values are $1, $42, $1,000,000, $9999999999999.95, and "'; DROP TABLE salary; --". As someone who has written input validation code for web forms on a few occasions, I personally give you my blessing to subvert them.

Comment by sketerpot on Does the Utility Function Halt? · 2015-01-28T04:30:35.810Z · LW · GW

I'm not entirely sure what your argument is yet, but here's a simple example utility function that might be interesting as a baseline:

def utility(universe):
    return 42

This function halts for all inputs, and assigns each input a desirability value that can be compared with others. What sort of utility function are you imagining?

Comment by sketerpot on Rationality Quotes October 2014 · 2014-10-04T02:48:19.054Z · LW · GW

It would definitely be a rationality quote if it went on to quote the part where Eric Flint decided to test his hypothesis by putting some of his books online, for free, and watching his sales numbers.

Comment by sketerpot on [moderator action] Eugine_Nier is now banned for mass downvote harassment · 2014-07-04T19:49:36.304Z · LW · GW

The Reddit guys really, really dislike doing schema updates at their scale. They were getting very slow, and their replication setup was not happy about being told to, say, index a new column while people are doing lots of reads and writes at the same time. So they eventually said "to hell with it; we'll just make a document database, with no schema, and handle consistency problems by not handling them. Man, do not even ask us about joins." This seems to have made them much happier than the 'better' database design they used to use, which is important when you're a too-small team dealing with terrifying scaling issues, and you know that a lot of people are watching you because they are the ones causing the scaling issues.

This design sure does make writing SQL queries a pain, though, and it's less than ideal for a site like Less Wrong, which doesn't do much changing the code.

Comment by sketerpot on Rationality Quotes June 2014 · 2014-06-21T22:26:09.142Z · LW · GW

"Focus on the future productivity of the asset you are considering. [...] If you instead focus on the prospective price change of a contemplated purchase, you are speculating. There is nothing improper about that. I know, however, that I am unable to speculate successfully, and I am skeptical of those who claim sustained success at doing so. Half of all coin-flippers will win their first toss; none of those winners has an expectation of profit if he continues to play the game. And the fact that a given asset has appreciated in the recent past is never a reason to buy it."

-- Warren Buffett, in some thoughts on investing.

Comment by sketerpot on A puzzle concerning CS major vs. engineering major salaries · 2014-04-10T04:13:42.964Z · LW · GW

If it makes you feel better, I studied computer science but frequently feel a sense of inadequacy because it feels less hard core than "real engineering".

Your sense of inadequacy is probably unjustified. I studied electrical engineering and computer science. Within both fields there's a wide range of hardcore-ness. In both fields you can find people who do incredibly difficult things, and a much larger group of people who do the bare minimum, and people everywhere in-between. I have seen some startlingly incompetent people with engineering degrees, so the lower bound here is pretty low.

Comment by sketerpot on A puzzle concerning CS major vs. engineering major salaries · 2014-04-10T04:02:55.996Z · LW · GW

So if coming from a top school makes SV employers think (correctly or incorrectly) that you're a top programmer, this could go a way towards explaining the salary thing.

This also works if coming from a top school correlates with some factor that makes SV employers think you're a top programmer. The most obvious example of such a factor is programming skill: you'd expect people at top schools to program better, on average, than people from obscure schools.

Comment by sketerpot on Rationality Quotes January 2014 · 2014-02-03T08:54:40.058Z · LW · GW

Have you heard a baby being born? A baby is all like "AAAAA! AAAAA! AAAAAAA!", except less textual and more piercing in pitch. Show me a definition of "dignified" which encompasses such shrieking, and I'll show you a definition of "dignified" which lacks mainstream recognition.

Comment by sketerpot on Rationality Quotes January 2014 · 2014-01-29T02:51:33.515Z · LW · GW

I'd say that the process of childbirth is a clear, up-front warning that it definitely won't be.

Comment by sketerpot on How to become a PC? · 2014-01-27T04:54:33.979Z · LW · GW

Not only does exercise become its own reward, but skipping exercise becomes its own penalty -- you feel physically crappy if you go too long without getting your fix. I see this as a good thing.

Comment by sketerpot on How to become a PC? · 2014-01-27T04:51:19.289Z · LW · GW

Exercising with someone is also an great way to socialize if you're a quiet person, and ill-at-ease with small talk. Pauses in conversation are natural when people are breathing heavily, there's always at least one shared topic you can talk about, and the exertion tends to make people more cheerful.

Comment by sketerpot on Physics grad student: how to build employability in programming & finance · 2014-01-11T17:31:44.318Z · LW · GW

Seconded; that's the book I learned from, and would have been my runner-up recommendation. In particular, its pictures are excellent, and there are loads of them.

Comment by sketerpot on Physics grad student: how to build employability in programming & finance · 2014-01-10T19:59:52.115Z · LW · GW

I don't know specific techniques to design good algorithms for problems.

I would suggest reading an introductory book on algorithms and data structures. There are a number of good ones, and none of them is strictly better than the rest, but for your case I would recommend Steve Skiena's Algorithm Design Manual, which can probably be found in your university library. It's very readable, discusses how to go about solving algorithmic problems, and has a lot of breadth.

This is some of the higher bang-for-the-buck knowledge in CS, and surprisingly relevant to the Real World.

Comment by sketerpot on Handshakes, Hi, and What's New: What's Going On With Small Talk? · 2014-01-03T21:38:34.713Z · LW · GW

I believe SMTP uses "HELO", actually (or "EHLO" to enable some extensions). The server then indicates that it heard the HELO command, often with a cheery remark like "Pleased to meet you! I'm a server! :-D"

This is one of the more charming aspects of the internet's plumbing.

Comment by sketerpot on Harry Potter and the Methods of Rationality discussion thread, part 28, chapter 99-101 · 2013-12-14T20:17:22.992Z · LW · GW

"Verres" came from combining "Vassar" and "Herreshoff". Here's the thread you're remembering.

Comment by sketerpot on Rationality Quotes December 2013 · 2013-12-03T06:22:44.834Z · LW · GW

If we could achieve eternal life through the clever use of linguistic ambiguity, then post-structuralist continental philosophers would have defeated death long ago. What would the world be like, I wonder, if all forms of cleverness were useful? A candidate for weirdtopia, probably.

Comment by sketerpot on 2013 Less Wrong Census/Survey · 2013-11-25T04:52:44.664Z · LW · GW

Took the survey. Cooperated because most puzzles which explicitly use the words "cooperate" and "defect" have been created in such a way as to make cooperation the better choice.

(Considering my fairly low chances of winning, a deep analysis would have had only recreational value, and there were other fun things to do.)

Comment by sketerpot on Open Thread, September 23-29, 2013 · 2013-09-26T05:56:00.574Z · LW · GW

Look into cloud computing. It's new enough not to have made it into many curricula yet.

For a decent summary, here's a pretty well-written survey paper on cloud computing.. It's three years old now, but not outdated.

Comment by sketerpot on Open Thread, September 23-29, 2013 · 2013-09-24T23:16:30.770Z · LW · GW

It's a good start, but I notice a lack of actual programming languages on that list. This is a very common mistake. A typical CS degree will try to make sure that you have at least basic familiarity with one language, usually Java, and will maybe touch a bit on a few others. You will gain some superpowers if you become familiar with all or most of the following:

  • A decent scripting language, like Python or Ruby. The usual recommendation is Python, since it has good learning materials and an easy learning curve, and it's becoming increasingly useful for scientific computing.

  • A lisp. Reading Structure and Interpretation of Computer Programs will teach you this, and a dizzying variety of other things. It may also help you achieve enlightenment, which is nice. Seriously, read this book.

  • Something low-level, usually C.

  • Something super-low-level: an assembly language. You don't have to be good at writing in it, but you should have basic familiarity with the concepts. Fun fact: if you know C, you can get the compiler to show you the corresponding assembly.

You should take the time to go above-and-beyond in studying data structures, since it's a really vital subject and most CS graduates' intuitive understanding of it is inadequate. Reading through an algorithms textbook in earnest is a good way to do this, and the wikipedia pages are almost all surprisingly good.

When you're learning git, get a GitHub account, and use it for hosting miscellaneous projects. Class projects, side projects, whatever; this will make acquiring git experience easier and more natural.

I'm sure there's more good advice to give, but none of it is coming to mind right now. Good luck!

Comment by sketerpot on Large introductory science classes · 2013-09-17T00:43:10.152Z · LW · GW

As far as I can tell, a significant fraction of the people in every major don't really understand it, don't care very much, and are continually half-assing everything. The problem with just flunking these guys is that they can still be valuable to employers, and their tuition money is nice to have.

Comment by sketerpot on Mistakes repository · 2013-09-09T21:28:45.781Z · LW · GW

A good, lightweight rule of thumb: before making a major life decision, spend at least an hour googling around for relevant information, especially from people who've done the thing you're contemplating. Chances are, your experiences will not be so different from theirs.

Then, seriously consider at least one alternative.

Comment by sketerpot on Mistakes repository · 2013-09-09T20:58:29.215Z · LW · GW

Further, people outside the nerd community have a broader emotional repertoire.

I would be very interested in hearing more about this -- my set of friends has a decidedly nerdy bias. Am I missing out on some feelings?

Comment by sketerpot on Types of recursion · 2013-09-04T19:10:01.367Z · LW · GW

Formally, I believe the first form can be produced by a regular grammar, but the second form can not. Check out the Chomsky hierarchy for a rundown on the power of each type of grammar.

Comment by sketerpot on Rationality Quotes September 2013 · 2013-09-04T08:31:22.191Z · LW · GW

That's an surprisingly forgiving thing to say. She lives in a place where eating legs to prevent starvation is a venerable military tradition, and a non-zero number of people end up in the Girls' Working School.

Comment by sketerpot on Harry Potter and the Methods of Rationality discussion thread, part 27, chapter 98 · 2013-08-29T02:40:20.808Z · LW · GW

This also has the advantage of being cheap in bulk, since it has so many industrial uses. Current prices are under $400/ton.

Comment by sketerpot on Open thread, August 26 - September 1, 2013 · 2013-08-28T22:11:34.476Z · LW · GW

Maybe a naive question, but you've got me curious: why is it the standard of care at some heart centers, rather than most or none? Is it a matter of cost, or are the benefits you mentioned not well-established, or are heart centers slow to change their standard of care? Or is it some fourth thing I didn't think of?

Comment by sketerpot on What Bayesianism taught me · 2013-08-13T22:13:46.536Z · LW · GW

This is actually a really tidy example of Bayesian thinking. People send various types of emails for a variety of reasons. Of those who send penis extension pill emails, there are (vaguely speaking) three possible groups:

  1. People who have invented penile embiggening pills and honestly want to sell them. (I've never confirmed anybody to be in this group, so it may be empty.)

  2. Scammers trying to find a sucker by spamming out millions of emails.

  3. Trolls.

If you see emails offering to "Eml4rge your m3mber!!", this is evidence for the existence of someone from one or more of these groups. Which group do you think is largest? Those spam emails are evidence for all of these, but not such strong evidence for choosing between them.

Comment by sketerpot on [LINK] Hyperloop officially announced — predictions, anyone? · 2013-08-13T03:19:29.955Z · LW · GW

An interesting bit about the economics of it:

By building it on pylons, you can almost entirely avoid the need to buy land by following alongside the mostly very straight California Interstate 5 highway, with only minor deviations when the highway makes a sharp turn.

The pylons are the single biggest cost, but by building it this way, they can avoid almost all the expense and delays that come from buying land and trying to get a right-of-way -- they can just use one that already exists. Upon hearing this, the cost estimates no longer sound too good to be true.

Comment by sketerpot on Rationality Quotes August 2013 · 2013-08-03T02:22:52.447Z · LW · GW

Such a threat can also be effective for asymmetrical violence -- no matter which way the asymmetry goes.

Comment by sketerpot on Rationality Quotes August 2013 · 2013-08-03T02:21:26.659Z · LW · GW

He just needs to get Saber to say it. Saber often tells people, in a bluntly matter-of-fact way, that they're making a mistake. Rin knows this. If Shiro said it, though, she'd think it was some kind of dominance thing and get mad.

(Maybe I'm over-analyzing this.)

Comment by sketerpot on A thought on the value of "rationality" as a value · 2013-08-01T06:38:48.554Z · LW · GW

Do you know what the best thing is? The best thing is when you habitually recognize the most common forms of human irrationality, and easily steer away from them. This works when you're short on will power, when you're sleepy, when you're drunk, when you're under the influence of religious experiences; whenever. It works because it doesn't require any real effort, in the moment. The effort comes when you try to train yourself to think like this, and you can do that beforehand, at your leisure.

(This isn't actually the Best Thing. The real Best Thing is practically unachievable, and only a superintelligent friendly AI can tell you precisely how unachievable it is. But this is still pretty great: a way to be reasonable without much depleting your supply of willpower. Reasonable by human standards, I mean.)

Comment by sketerpot on Rationality Quotes from people associated with LessWrong · 2013-07-30T04:24:13.147Z · LW · GW

There's a theorem which states that you can never truly prove that.

Comment by sketerpot on The Robots, AI, and Unemployment Anti-FAQ · 2013-07-28T21:09:58.108Z · LW · GW

You'd think that more severe punishment would have a correspondingly greater deterrent effect, but that doesn't seem to be the case. What matters much more than the severity of the punishment is its likelihood. Sure, you might starve in the streets if you get caught jacking off in some high-born lady's nether-garments -- if you get caught. And, let's be honest: you're probably not going to get caught, and if you get caught, you're probably not going to be reported to your employer.

In any case, all that talk of starvation is far-off, way in the future; the laundry is right here, and offers immediate gratification. IQ is pretty strongly correlated with the ability to delay gratification, and (though I don't have a citation for this) people seem to care about the future a lot less when they're horny.

Comment by sketerpot on Superrationality and network flow control · 2013-07-23T06:48:53.330Z · LW · GW

Unfortunately, since Reno backs off later than Vegas, a mixed Vegas/Reno network ends with the Reno machines consuming the vast majority of bandwidth.

Unless they're idle most of the time, that is. Anybody who's run a modern BitTorrent client alongside a web browser has been in this situation: the congestion control protocol used by most BitTorrent clients watches for packet delays and backs off before TCP, so it's much lower-priority than just about everything else. Even so, it can end up using the vast majority of bandwidth, because nobody else was using it.

Comment by sketerpot on Harry Potter and the Methods of Rationality discussion thread, part 20, chapter 90 · 2013-07-04T06:24:45.805Z · LW · GW

It does sound like exactly the kind of clever hack Harry would use to get an indefinite healthy lifespan, though.

Comment by sketerpot on Harry Potter and the Methods of Rationality discussion thread, part 20, chapter 90 · 2013-07-04T06:18:19.130Z · LW · GW

That post consisted of (fairly minor) Evangelion spoilers, encoded with rot13 for the benefit of people who haven't seen it yet.

(For completeness' sake: the language of Ente Isla is English with a bunch of letter substitution, and the language that Ledo speaks in Gargantia is a letter-substituted offshoot of German. They're similar to rot13, but much more pronounceable, since vowels map to vowels and consonants to consonants. More info here.)

Comment by sketerpot on Useful Concepts Repository · 2013-06-10T22:07:42.592Z · LW · GW

Thomas Schelling proposed a useful strategy: make small threats for small infractions, and then follow through on them. This gives credibility to your larger threats, without too much inconvenience for either party.

(And, of course, try to make the whole thing as predictable as possible; never be capricious with your own authority.)

Comment by sketerpot on Rationality Quotes June 2013 · 2013-06-02T10:14:33.891Z · LW · GW

Even if altruism turns out to be a really subtle form of self-interest, what does it matter? An unwoven rainbow still has all its colors.

Comment by sketerpot on Post ridiculous munchkin ideas! · 2013-05-19T20:58:49.098Z · LW · GW

1% fees are way too high. Vanguard has some good funds with fees as low as 0.1%.

That number is a bit out of date; they recently cut fees for many (most?) of their funds. Now I'm only paying 0.05% on my main index fund. I'm pretty cheerful about this.

Comment by sketerpot on Justifiable Erroneous Scientific Pessimism · 2013-05-08T22:27:59.740Z · LW · GW

It wasn't until the 1850s that Ångström discovered that elements both emit and absorb light at characteristic wavelengths, which is what spectroscopic analysis of stars is based on, so I'm leaning toward justifiable.

Comment by sketerpot on Googling is the first step. Consider adding scholarly searches to your arsenal. · 2013-05-07T22:51:02.623Z · LW · GW

Correct me if I'm wrong, but most of those look like the result of fishing around for positive results, e.g. "We can't find a significant result... unless we split people into a bunch of genotype buckets, in which case one of them gives a small enough p-value for this journal." I haven't read the studies in question so maybe I'm being unfair here, but still, it feels fishy.