Description vs simulated prediction 2020-04-22T16:40:02.999Z · score: 27 (7 votes)
The unexpected difficulty of comparing AlphaStar to humans 2019-09-18T02:20:01.292Z · score: 129 (47 votes)
Welcome to Less Wrong! (11th thread, January 2017) (Thread B) 2017-01-16T22:25:56.482Z · score: 1 (2 votes)
Stupid Questions August 2015 2015-08-01T23:08:49.398Z · score: 7 (8 votes)


Comment by grothor on Solar system colonisation might not be driven by economics · 2020-04-24T21:04:05.257Z · score: 5 (3 votes) · LW · GW

Vastly cheaper average cost for resources that can be mined in space might open up opportunities for economically valuable things that we currently won't do on account of the Earth cost of those resources. To use your glass/lake metaphor, if all we have available for water is a dozen glasses per day per person, we probably won't have much of a swimming pool or sprinkler system industry. If we find ways to pipe water from the lake, we might see much more demand for large volumes of water.

Comment by grothor on Discontinuous progress in history: an update · 2020-04-14T20:19:23.558Z · score: 6 (4 votes) · LW · GW

I agree that it would be interesting to look at evidence from further in the past or from non-Western progress.

Unfortunately, we found researching progress from before roughly 1700-1800 (and sometimes even later) to often be quite difficult. Most sources are vague, disagree with each other, or have clear signs of unreliability. Even when we have good accounts of what the state of the art was at some particular time, it was difficult to establish a progress trend leading up to it.

You're probably right that professional historians would be good at sorting some of these problems out. Usually when we did contact subject matter experts during the investigation, they could at help us to reality check out findings, but we did not try to get them to actually do work for us.

Comment by grothor on Rohin Shah on reasons for AI optimism · 2020-04-02T05:10:17.063Z · score: 2 (2 votes) · LW · GW

Neat idea!

If someone here thinks this is easy to do or that they can make it easy for us to do it, let me know.

Comment by grothor on What will be the big-picture implications of the coronavirus, assuming it eventually infects >10% of the world? · 2020-03-02T21:42:38.707Z · score: 4 (2 votes) · LW · GW

Those predictions are based on 80% of cases being mild. My claim is that if 90% of cases are undiagnosed, then substantially less than 20% will be severe.

Comment by grothor on What will be the big-picture implications of the coronavirus, assuming it eventually infects >10% of the world? · 2020-03-01T19:30:13.827Z · score: 5 (3 votes) · LW · GW

I'm also arguing that we might just have many fewer severe cases than these right-tail estimates are indicating. So far, Hubei has only had .1% of their population get confirmed cases, for example, and I think that many scenarios in which >10% of people are infected globally are ones in which the actual number of cases in Hubei is much larger than .1%.

I also think there are more reasons for expecting fewer severe cases in many parts of the world than in China, like the increased prevalence of smoking in China, relative to places like the US.

Comment by grothor on What will be the big-picture implications of the coronavirus, assuming it eventually infects >10% of the world? · 2020-03-01T18:20:20.149Z · score: 13 (9 votes) · LW · GW

I think the estimates in your links are not central estimates, even conditioning on 10% of the world being infected. The analysis in the Medium article basically assumes the worst case on every axis. So yeah, that will look pretty bad. And I think it is a good way to get a picture of what the right tail on this looks like. But it's pretty far from the most likely outcome. Mitigating factors that are ignored:

  • China got a lot better at managing the epidemic over time, and everyone can learn from that. (See the WHO report linked in the reddit post:

  • Related to the above, we're starting to get a sense of how it spreads, which should help us to slow the spread

  • Fatality rates so far may be much smaller than these worst case estimates, if the number of mild cases that were not detected is large. This is more likely to be true in Wuhan, where capacity for testing may have been stressed as well as capacity for treating. It is also more likely in the worlds where where ~50% of people become infected

  • Most published estimates of R0 are closer to the smaller end of the scale reported in that Medium article (2-2.5 from the WHO, 2-3 from JAMA, vs 1.4-3.8), and for comparison to influenza, 1.28 is on the smaller end of flu outbreak R0 estimates (~1.5 for the 2009 outbreak, and why did he use a point value with three significant figures for such an imprecisely measured thing?)

  • Any measure to slow down the virus will spread out the stress to hospitals. It's not as if we'll wake up one morning and half of all people in our town will be infected. We should be less concerned about how many people will be infected and more concerned about how many people will be infected at once.

  • Warmer weather usually makes these things less bad, which may slow the spread over the coming months

  • There is some evidence that east Asian populations are more susceptible (

If it looks like I'm reaching for arguments for not being worried, that's because I kind of am (though I do think everything I said here is true). But that's how the Medium article reads to me. It is very unlikely that all of the bad things will happen and none of the good things will happen.

Comment by grothor on AlphaStar: Impressive for RL progress, not for AGI progress · 2019-11-15T14:14:35.425Z · score: 1 (1 votes) · LW · GW

I'm not sure how surprised to be about middle of training, versus final RL policy. Are you saying that this sort of mistake should be learned quickly in RL?

Comment by grothor on AlphaStar: Impressive for RL progress, not for AGI progress · 2019-11-14T14:47:50.631Z · score: 9 (2 votes) · LW · GW

The replay for the match in that video is AlphaStarMid_042_TvT.SC2Replay, so it's from the middle of training.

Here is the relevant screen capture:

Comment by grothor on A Personal Rationality Wishlist · 2019-10-30T08:38:37.965Z · score: 3 (2 votes) · LW · GW

One thing that might be learned from bicycles is that their wonderfulness is partially contingent how you come to use them, and how much you seek out improvements in your relationship with them.

Most people ride with the saddle too low and their tire pressure too low (though recreational cyclists on road bikes will often have too much air in their tires). People tend to ride too close to the side of the road, and ride in too high of a gear (that is, they pedal too slowly). These are not universal. Many people get some or all of these things right or have good reasons for not doing them.

I'm not entirely sure why people get these things wrong so often, but it is at least partially because the wrong way feels intuitively correct, at least to begin with. And things like saddle height and gear ratio seem to have a lot to do with how the bike was configured when the person first started riding it. But all of these are things that can easily be learned from talking to experienced people, which most people never do.

So I think the lesson is: Seek out the correct ways of doing things, even in cases where you can just look at a thing and see basically how it works, so that it seems hard to get it wrong, and where it seems pretty wonderful even without help.

Comment by grothor on The unexpected difficulty of comparing AlphaStar to humans · 2019-10-01T11:31:17.435Z · score: 1 (1 votes) · LW · GW

Sorry I worded that really poorly.

It's all good; thanks for clarifying. I probably could have read more charitably. :)

That cognitive process of visual recogniton and anticipation is simply inseparable of the athleticism aspect.

Yeah, I get what you're saying. To me, the quick recognition and anticipation feels more like athleticism anyway. We're impressed with athletes that can react quickly and anticipate their opponent's moves, but I'm not sure we think of them as "smart" while they're doing this.

This is part of what I was trying to look at by measuring APM while in combat. But I think you're right that there is no sharp divide between "strategy" or being "smart" or "clever" and "speed" or being "fast" or "accurate".

Comment by grothor on The unexpected difficulty of comparing AlphaStar to humans · 2019-09-20T17:52:38.362Z · score: 2 (2 votes) · LW · GW

Being dumb and fast is simply more effective than smart and slow.

But it is unclear what the trade-off actually is here, and what it means to be "fast" or "smart". AI that is really dumb and really fast has been around for a while, but it hasn't been able to beat human experts in a full 1v1 match.

Much of the strategy in the game is build around the fact that players are playing with limited resources of athleticism (i.e. speed and accuracy) so it follows that you can't necessarily separate the two skill categories and only measure one of them.

The fact that strategy is developed under an athleticism constraint does not imply that we can't measure athleticism. What was unexpected (at least to me) is that, even with a full list of commands given by the players, it is hard to arrive at a reasonable value for just the speed component(s) of this constraint. It seems like this was expected, at least by some people. But most of the discussion that I saw about mechanical limitations seemed to suggest that we just need to turn the APM dial to the right number, add in some misclicking and reaction time, and call it a day. Most of the people involved in this discussion had greater expertise than I do in SCII or ML or both, so I took this pretty seriously. But it turns out you can't even get close to human-like interaction with the game without at least two or three parameters for speed alone.

Comment by grothor on The unexpected difficulty of comparing AlphaStar to humans · 2019-09-18T20:20:17.165Z · score: 2 (2 votes) · LW · GW

Thanks! I've updated the version on our site ( and I'm working on updating the post here on LW.

Comment by grothor on Which parts of the paper Eternity in Six Hours are iffy? · 2019-05-20T19:00:41.204Z · score: 18 (4 votes) · LW · GW

In the order that they appear in the paper, these are a few of the parts that seemed iffy to me. Some of them may be easily shown to be either definitely iffy, or definitely not-so-iffy, with a little more research:

As for nuclear fusion, the standard fusion reaction is 3H +2H→4He +n+ 17.59 MeV. In MeV, the masses of deuterium and tritium are 1876 and 2809, giving an η of 17.59/(1876 + 2809) = 0.00375. We will take this η to be the correct value,because though no fusion reactor is likely to be perfectly efficient, there is also the possibility of getting extra energy from the further fusion of helium and possibly heavier elements.

I'm not sure what existed at the time the paper was written, but there are now proposals for fusion rockets, and using the expected exhaust velocities from those might be better than using the theoretical value from DT fusion.

The overall efficiency of the solar captors is 1/3, by the time the solar energy is concentrated, transformed and beamed back to Mercury.

I feel like I'm the only one that thinks this Dyson sphere method is a little dubious. What system is going to be used to collect energy using the captors and send it to Mercury? How will it be received on Mercury? The total power collected toward the end is more than W. If whatever process is used to disassemble the planet is 90% efficient, the temperature required to radiate the waste heat over Mercury's surface area is about 7000K. This is hotter than the surface of the sun, and more than twice the boiling point of both iron and silica. In order to keep this temperature below the boiling point of silica, we would either need the process to be better than 99.98% efficient, to attach Mercury to a heat sink may times the size of Jupiter, or to limit power to about W. If melting the planet isn't our style, we need to limit power to about W.

I don't think this kills their overall picture. It "only" means the whole process takes a few orders of magnitude longer.

Of the energy available, 1/10 will be used to propel material into space(using mass-drivers for instance [37]), the rest going to breaking chemical bonds, reprocessing material, or just lost to inefficiency. Lifting a kilo of matter to escape velocity on Mercury requires about nine mega-joules, while chemical bonds have energy less that one mega-joule per mol. These numbers are comparable, considering that reprocessing the material will be more efficient than simply breaking all the bonds and discarding the energy.

The probes will need stored energy and reaction mass to get into the appropriate orbit, unless all the desired orbits intersect Mercury's orbit. Maybe this issue can be mitigated by gradually pushing Mercury into new orbits via reaction force from the probes. Or maybe it's just not much of a limitation. I'm not sure.

Because practical efficiency never reaches the theoretical limit, we’ll content ourselves with assuming that the launch system has an efficiency of at least 50%

This seems pretty optimistic. In particular, making a system that launches large objects at .5. Doing this over the distance from the sun to Earth requires an average force of about N per kg. For .9 and .99, it requires about 8 and about 35 this force/mass, respectively. I don't know what the limiting factor will be on these things, but this seems pretty high, and suggests that the launcher would need to be a huge structure, and possibly a bigger project than the Dyson swarm.

I also have some complaints about the notation, which I will post later, and possibly other things, but this is what I have for now.

Comment by grothor on What are questions? · 2019-01-09T19:03:26.330Z · score: 4 (3 votes) · LW · GW

Do animals ever 'ask questions'?

I've seen animals do things that seem like they are trying to resolve uncertainty (like a cat batting at some unfamiliar object with his paw), or make a request (a dog begging for food) which both seem similar to asking questions.

Comment by grothor on Reflections on Berkeley REACH · 2018-06-13T22:12:36.174Z · score: 11 (7 votes) · LW · GW

I slept on a couch while I was in town for EA Global. I'm glad that I did. My sleep quality wasn't great, mainly because I'm sensitive to light and sound and I forgot to bring an eye mask or earplugs. But I was reasonably well rested during the conference, nonetheless. Having Soylent available in the morning was nice, too, because I didn't have to spend time or mental energy finding something to eat before heading to SF for the conference.

But mostly, I liked the people. There were always friendly, interesting, and helpful people around, and everyone made me feel welcome from the beginning. We discussed things and played games, and I made some friends. When I needed to go to sleep in the main space while others wanted to keep talking, we quickly found a solution and nobody made me feel guilty.

A few minor complaints:

  • It's tough to coordinate things with six or seven people and one shower, especially when everyone is on the same schedule in the morning. I had been warned about this, and it's not clear to me what could be done, but it was a problem nonetheless.
  • When I reserved the couch, it wasn't clear to me what would be available, in terms of bedding, towels, etc. I just assumed I would be on my own, but it might be good to communicate this more explicitly.
  • There was some slight confusion about who was in what room and what was reserved. It might be good to have some simple way to designate this. Maybe a place to stick a name tag outside the doors to the rooms, or above the couches?

All in all it was great, and I hope I can come back soon!

Comment by grothor on Welcome to Less Wrong! (11th thread, January 2017) (Thread B) · 2017-03-29T04:12:17.962Z · score: 1 (1 votes) · LW · GW

I think one of my problems is that I don't actually think that much about what I read.

Do you mean that you don't put much thought into deciding what to read, or that when you read something you don't reflect on it?

Comment by grothor on Stupidity as a mental illness · 2017-02-12T16:06:35.459Z · score: 0 (0 votes) · LW · GW

They do, but there are also efforts to develop tests that measure other important aspects of cognition, which have an important bearing on things like how well you can function in society and how much of a risk you are to other people (these tests are, more or less, measuring what the rationality community might refer to as rationality). See, for example, What Intelligence Tests Miss: The Psychology of Rational Thought by Keith Stanovich.

Comment by grothor on Welcome to Less Wrong! (11th thread, January 2017) (Thread B) · 2017-02-09T02:18:07.324Z · score: 0 (0 votes) · LW · GW

(Also, the place to ask this sort of question might be the current Open Thread:

Comment by grothor on Welcome to Less Wrong! (11th thread, January 2017) (Thread B) · 2017-02-09T02:16:34.552Z · score: 1 (1 votes) · LW · GW

I do this too. I don't think that it is abnormal

Same here. I find that simulating other people's reaction to my arguments, mistakes, or work that I've done is helpful. When I want to find logical errors in my arguments, I imagine explaining them to someone with a strong background in philosophy. When something isn't working well in the lab, I imagine explaining the situation to someone with experience, and if I feel embarrassed or like they're about to offer a super obvious solution, it usually means I've made some silly mistake. Also, getting back to Sandi's question, some of the most helpful people for me to simulate are people that I met through the LessWrong meetup in Austin.

you could consider enrolling in graduate school

My classmates in grad school are often, but not always, a good source of more productive intellectual conversations. There is still sometimes an issue of differences in the style of thinking that people appreciate, or the kinds of topics they're interested in. And, of course, just because someone has had enough success in graduate school to stick around and be a friend for a few years doesn't mean they don't succumb to a variety of biases that can make it harder to have the kinds of conversations you're seeking.

Comment by grothor on Open thread, Feb. 06 - Feb. 12, 2017 · 2017-02-06T21:44:49.749Z · score: 0 (0 votes) · LW · GW

It's not an escape orbit, it's just a more eccentric orbit (unless it is much higher). Still, you are correct that my second solution will not work (see my second edit).

I started solving the trajectory for an exponentially decaying air density and a drag force that scales linearly with density and quadratically with velocity, but I did not immediately see the solution to the resulting differential equation, nor did I see a clever trick for avoiding the calculation. I'll look at it again later.

Comment by grothor on Open thread, Feb. 06 - Feb. 12, 2017 · 2017-02-06T21:07:57.354Z · score: 1 (1 votes) · LW · GW

Air density drops with increasing altitude. The object dropped from a higher altitude reaches a higher speed before reaching the denser air where object B is dropped. I'm not sure if a realistic density profile will allow object A to arrive first, but it is easy to show that there is some air density profile which will cause this to happen. I suspect that a necessary condition is that object A is already above the terminal velocity at object B's initial height when it reaches that height.

Or, if you interpret "free fall without any initial relative velocity against the planet" to say that it is stationary with respect to both the Earth's center of mass and the Earth's surface, then drop B from a geostationary orbit, and A from a higher position, where it will have insufficient angular velocity to be in orbit. It will fall to Earth, while B's orbit will decay.

Edit: It is permitted to assume that they are dropped over the equator, since the problem says "Central Atlantic".

Edit 2: Wait, I did this wrong. If object A has a rotational velocity of 1/day, and it is at an altitude higher than a geostationary orbit, it will be in some larger more eccentric orbit, so it won't fall to Earth any sooner than object B.

Comment by grothor on Stupid Questions December 2016 · 2017-02-06T18:24:46.212Z · score: 1 (1 votes) · LW · GW

I recently had a dream in which an unspecified organization was anticipating trouble from an unspecified group of people. One member of the organization remarked that, should things get bad, they had seven gay 400 lb game theorists that could be called in on a moment's notice.

What sort of problem is solved by the deployment of unusually heavy game theorists? Does it matter that they are gay? What kind of organization would have such resources at its disposal?

Comment by grothor on Open thread, Jan. 30 - Feb. 05, 2017 · 2017-02-04T17:22:48.538Z · score: 1 (1 votes) · LW · GW

It is completely unsurprising to me that there is an amount of energy use that makes one feel clearer and more productive compared to the sedentary graduate student, and that that can vary from person to person and over time in the same person as their physiological state adapts and changes.

I don't think that anybody here is surprised by this. What's surprising is not that there is an amount of exercise that is required for me to feel alert and productive, it's that the relationship between my mood and my exercise seems to follow a single, simple, specific rule. You explain the reasons why this should be surprising in your first paragraph. To illustrate why this seems surprisingly simple, here is a list of things that seem not to affect my productivity, holding total work constant:

-Heart rate


-Time of day

-Eating before or during the ride*

-How fatigued I am from the day before**

-Average Power

-Normalized power

-My functional threshold power at the time (a measure of fitness)

-"Training Stress Score"

The last three of these are metrics that are part of a physiological model. The model is somewhat simplistic, given the complexity of humans that you have mentioned, but the metrics have proven to be useful for athletic training (anyone who is interested in a more detailed description, which is still written for the layman, should check out Training and Racing with a Power Meter by Coggan and Allen). More to the point, there's no particular reason (that I can see) to expect total work to win out over any of the other things on this list.

But I do notice two things, having actually written down this list. First, each of these does seem to have a small non-zero effect. As I already mentioned, doing a little more than 1000kJ over a longer duration does seem to be okay, and my FTP does seem to shift my ideal amount of work a bit. Second, these are tightly coupled to each other. You can boil duration, average power, total work, normalized power, TSS, and FTP down to four variables, one of which is total work, and another of which will usually be 90% determined by total work. Furthermore, fatigue and how much I eat will have an effect on how much of a work I'm able or willing to do on a given day. This all means that it would be very easy to mistake a more complex relationship between some or all of these factors and my mood/cognition as a simple one, especially a simple rule that is bent slightly by external factors. I feel like this eliminates much of the confusion for me (the lesson here being that when I'm confused, I should stop, write down my confusion, and stare at it). However, it does not offer a strategy for venturing too far from the 900kJ rule without consequence.

Comment by grothor on Infinite Summations: A Rationality Litmus Test · 2017-02-02T19:57:58.061Z · score: 1 (1 votes) · LW · GW

When this sum hit the mainstream interwebz a while back, we had some discussion about it in the physics department where I work. The consensus was that it was misrepresented as a spooky non-intuitive fact about adding numbers, when really it's closer to a particular notation for assigning a finite value to a diverging sum that happens to be useful in physics*. Some of us were annoyed, because it feels like it's reinforcing this idea that math is impossibly opaque, a notion that we have to deal with on a regular basis when trying to teach physics to undergraduates.

Also, FWIW, I don't recall seeing this presented in my QFT class, but then again, I only took one semester.

*I think you're actually characterizing a it a little differently and a little more precisely, as a way of actually evaluating the sum, while subtracting off a term of order infinity, in a way that allows for certain kinds of manipulations that happen to be useful in physics.

Comment by grothor on Open thread, Jan. 30 - Feb. 05, 2017 · 2017-02-02T16:17:49.556Z · score: 2 (2 votes) · LW · GW

Could there be other substantial moderating differences between the days when you generate ~900 kJ and the days when you don't? (E.g., does your mental state before you ride affect how much energy you generate?

This could be the case, or there could be a common cause between the total work I do and my mood for the day. What makes me think this is less likely is that, when I'm following a training plan, the total work for the ride is largely determined days or weeks ahead of time. Then again, I will modify the day's workout on a training plan if I'm feeling shitty. Or it could just be that I noticed the pattern once when it happened by chance, then I expected it to continue, so it did (that is, it's more of a placebo than anything else). Then again, it wouldn't be hard for small effects like this to add up to the observed effect.

I actually did think about blinding it. I could modify some existing software to give me an intensity or duration that I don't know ahead of time, and that I don't have in front of me while I'm riding, and I could even not look at what it was until days or weeks later when I'm analyzing the results (or I could get even more hardcore and have someone else analyze it). The problem is that most of the motivation mechanisms I have for actually doing a worthwhile ride indoors require me to have access to a lot of this data. It would sort of be like trying to stay motivated in a game where you have no access to your score or whether you've eliminated another player.

Comment by grothor on How often do you check this forum? · 2017-02-01T23:20:20.574Z · score: 2 (2 votes) · LW · GW

I check once or twice most days.

  1. On average I'll maybe read two or three posts per day, comment once per week (though it comes in spurts), and vote once per day.
  2. Maybe 1/3-1/2 of link posts. Oftentimes, they're links to things I've already seen posted elsewhere (like Facebook)
  3. Browser on a desktop. Occasionally smartphone.
  4. SSC is the obvious answer. Also a few Facebook groups*, or people I follow on Facebook.

Much of the time, I'll just look at the recent comments to see what's getting activity. But when I look at the actual discussion posts, I usually find things worth clicking that I wouldn't have found by only looking at recent comments. I don't know why I do this. Maybe commenting about it here will make me stop.

Also, I feel like the LW meetup in Austin meets some of my need for the sorts of discussions that might otherwise be met by the website.

*Optimal Memes for Cosmopolitan Teens has become an unexpectedly useful place to hang out.

Comment by grothor on Open thread, Jan. 30 - Feb. 05, 2017 · 2017-02-01T21:03:20.860Z · score: 7 (7 votes) · LW · GW

I'm a cyclist and a PhD student, and I've noticed some patterns in the way that my exercise habits affect my productivity. I get a lot of data from every ride. While I'm riding, I measure heart rate and power, and if I'm outside, I also measure distance and speed. I've found that the total amount of energy that I produce, as measured by the power meter on my bike, is a useful metric for how I should expect to feel the rest of the day and the next day. In particular, if I generate between 800 kJ and 1000 kJ, I usually feel alert, but not worn out. If I do less, I feel like I've not had enough exercise, and I either feel restless or like my body is in lazy recovery mode. If I do more, I feel physically worn out enough that it's hard to work for an extended period of time, especially on the days that I am working in the lab.

What I think is most curious about this is that it is relatively independent of my fitness or the intensity of the ride. If I go balls-out the whole time, it takes slightly fewer kJ to make it hard to focus, and if I go super easy, it takes a bit more. It's the same with fitness. The difference between the power I can sustain for an hour when I'm in form for racing vs when I've barely been riding at all is about 25-30%, but the difference in the amount of mechanical work to make me unproductive is about 10%. (You might notice this gives me an incentive to stay in shape; I can do the same amount of work for the same productivity boost in less time when I'm more fit.)

So, what's definitely true is that the amount of work I put in on the bike is a useful metric for maximizing my productivity. What's unclear is if the amount of work is in some way fundamental to the mental state that it puts me in. The most obvious possibility is that it mainly has to do with the number of calories I burn; this is consistent with the finding that I need to do more work to feel tired when I'm more fit, since training will make you more efficient. But it's not obvious to me why this would be the case. When I'm in poor shape, an 800 kJ ride will have a much more drastic effect on my blood sugar than it will when I'm fit enough to race. It would be useful to venture outside the 800-1000 kJ range on days when I need to get work done.

I don't really know enough physiology to get any further than this. Does anybody else have experience with this sort of thing? Does anyone have empirically testable hypotheses? (Non-testable or not-testable-for-me hypotheses may be interesting as well.)

Comment by grothor on Feature Wish List for LessWrong · 2017-01-17T06:47:00.082Z · score: 2 (2 votes) · LW · GW

It would be helpful to have a few threads that are sticky, or otherwise easy to find. For example, the current open, welcome, and stupid questions threads. Today when I created that spurious welcome thread, I noticed a post made by a new user that seemed appropriate for the welcome thread and I wanted to link them to it. The link to the welcome thread at points to a 2015 edition. I tried a few different searches in the Google search bar, then checked a few of the tags that customarily go along with the welcome threads. Then I got anxious that I was double posting, and checked again. So I finally posted it, and within two hours, before I was even aware that I'd double posted, the thread got two new users posting on it, even though the original had sat idle for over a week.

This makes me think that I'm not the only one that had trouble finding it. The Google search that's integrated into the site is great for searching based on content and popularity, especially for older content, but it's slow to index, and sometimes the title of the link is misleading (it actually finds the original January 2017 Welcome thread, but the link shows up as January 2016). It looks like the way to have found it would have been ctrl-F on the discussion page. If the standard, regularly-reposted threads were sticky'd at the top, or had links on a sidebar or something, this wouldn't be an issue. A search that allows to filter by date would probably also suffice, so long as it indexes quickly enough.

I hope this doesn't sound like I'm making excuses; I made a mistake, and I feel appropriately embarrassed (and even as I type that, I get the mental image of Vaniver looking at me critically and saying "But do you?"). I realize that this may be mainly a case of me being bad at searching for things, and if I'm the only one who experiences this, then we can probably just not worry about it.

Comment by grothor on Open thread, Jan. 02 - Jan. 08, 2017 · 2017-01-16T22:28:26.263Z · score: 1 (1 votes) · LW · GW

I made the thread here:

I just copied all the text, added the same tags, changed the date and thread number (it's 11, but someone forgot to add tags on 10), and posted to discussion. If I somehow managed to miss that someone already made the post, then I assume you'll delete it or let me know and I'll delete it.

Comment by grothor on The Landmark Forum — a rationalist's first impression · 2017-01-07T07:27:20.527Z · score: 1 (1 votes) · LW · GW

Mostly, I just want TonyPaukar to come back and tell me more about this "10% satisfaction" guarantee.

Comment by grothor on Open thread, Jan. 02 - Jan. 08, 2017 · 2017-01-03T23:14:40.191Z · score: 1 (1 votes) · LW · GW

I may be misunderstanding the connection with the availability heuristic, but it seems to me that you're correct, and this is more closely related to the Dunning-Kruger effect.

What Dunning and Kruger observed was that someone who is sufficiently incompetent at a task is unable to distinguish competent work from incompetent work, and is more likely to overestimate the quality of their own work compared to others, even after being presented with the work of others who are more competent. What Viliam is describing is the inability to see what makes a task difficult, due to unfamiliarity with what is necessary to complete that task competently. I can see how this might relate to the availability heuristic; if I ask myself "how hard is it to be a nurse?", I can readily think of encounters I've had with nurses where they did some (seemingly) simple task and moved on. This might give the illusion that the typical day at work for a nurse is a bunch of (seemingly) simple tasks with patients like me.

Comment by grothor on Stupid Questions December 2016 · 2016-12-23T00:55:21.130Z · score: 0 (0 votes) · LW · GW

I don't think there is a one-size-fits-all answer for a "general audience" that would apply to all people around the world.

This is why I specified by education level (and I thought I'd specified Americans or Europeans, but apparently not), though I'll admit that I'd been thinking primarily in terms of English-speaking people (though this is an English forum, and I'm not likely to be writing for a non-English-speaking audience). I also didn't specify that I'm not really talking about cultural common knowledge; I'm not expecting a typical Londoner to have the same culinary knowledge as a typical person from Nashville.

However, the kinds of things that I think are generally regarded as common knowledge are also relatively culturally insensitive, and I do expect that the typical college graduate from London and the typical college graduate from Nashville have quite a lot of overlap in their secondary education curricula. When I say 'quite a lot', I just mean that, if you have a good understanding of one group's common common knowledge, you'll be able to use that with the other group, at least for things that are generally made for a "general audience". The main reason I think this is true is that watching British TV and watching American TV isn't any different, in terms of what I'm expected to know, apart from cultural references. Similarly, as an American, I've never really run into problems related to assumed knowledge while talking to non-Americans. (The main exception here might be history education.) Then again, a majority of the non-Americans that I talk to I meet either through either the rationalist community or academia, so there may be some selection bias. Also, it's possible that the wide proliferation of American media gives non-Americans a good sense of what they can assume Americans know. Am I wrong? Are American and European audiences sufficiently different that they usually require different accommodations?

There are few events aimed at a world audience - the Olympics, some United Nations events, so you could study some of those and see what they assume of people.

I like this idea, though I'm unsure how to find media that isn't written mainly for a particular nationality, and that assumes anything apart from English literacy. (That said, I do find the problem of making signage for an event like the Olympics to be interesting.)

Comment by grothor on Stupid Questions December 2016 · 2016-12-20T22:28:37.379Z · score: 1 (1 votes) · LW · GW

If there is the last member of the list, everything is just fine.

There is no last point between your nose and your monitor.

Let me pose a different problem, to demonstrate what I think is wrong with your argument.

You start with a reflective square slab that is half as thick as it is wide. You place another slab, which is half as thick as the first on top, then another half as thick as that. You continue doing this until your stack of slabs is as tall as it is wide. If you direct an ideal ray at this slab, along the symmetry axis of the stack, what does the ray do?

This situation is, once constructed, identical to the first ray described in your problem (the one that hits the face of the cube), but your argument would imply that the ray won't reflect back, because whichever slab it would reflect from has another slab shadowing it.

Comment by grothor on Stupid Questions December 2016 · 2016-12-20T21:32:16.292Z · score: 0 (0 votes) · LW · GW

By the symmetry you can argue that the ray hasn't reach the sphere.

Can you explain?

Comment by grothor on Stupid Questions December 2016 · 2016-12-20T21:29:04.838Z · score: 0 (0 votes) · LW · GW

This sounds familiar. Since every point between your nose and your computer monitor has the property X, that there exists another point between it and your computer monitor, no matter how many points you move your nose through, there's always more points it must go through before reaching the computer monitor. This is why, no matter how you try, you can never touch your nose to a computer monitor.

Comment by grothor on Stupid Questions December 2016 · 2016-12-20T21:19:44.713Z · score: 0 (0 votes) · LW · GW

The answer "cubes with no empty space are filled cubes" was perfectly decent, as was the verbal argument about limits that Viliam provided. But in case those weren't satisfying, I've written a more explicit version of the proof* that the ray travels zero distance between reaching the cube and reaching a sphere. It utilizes the solution to the geometric sum, which is proved using limits:

The proof (derivation?) is here:

I think you can just argue by symmetry that the ray must retro-reflect.

*At least, it looks like a proof to a physicist. It may not meet the standards of a proof to a mathematician.

Comment by grothor on Stupid Questions December 2016 · 2016-12-20T01:58:13.820Z · score: 1 (1 votes) · LW · GW

Is there a good way to find out what's common knowledge?

I feel like it would be handy to have a repository of things that, for example, a typical high school or college graduate knows. I think this would be useful for explaining things or writing about topics where you have too much domain knowledge to remember what it's like to be outside the field, and also for finding out if there are topics where you're lacking. Another case where I found myself wanting such a tool was when I recently got in a disagreement about whether a particular word was a niche thing that few people know, or a widely known word. Does anybody know of a good way of finding out what the "general audience" already knows? This kinda feels like a problem that writers have to solve all the time.

Comment by grothor on Stupid Questions December 2016 · 2016-12-20T01:32:42.042Z · score: 1 (1 votes) · LW · GW

Yeah, this is a thing, and I hear plenty of Americans make baffled complaints about it as well.

I don't know the answer, but this is my guess. A while back, there was a flurry of news sites talking about air conditioning being "sexist". The short version is that standards for climate control were all written when offices were full of men in suits. Times have changed, in terms of who's wearing what in which buildings, but things like building codes and temperature guidelines haven't caught up.

Comment by grothor on Feature Wish List for LessWrong · 2016-12-18T02:15:38.625Z · score: 7 (7 votes) · LW · GW

I very much like the idea of the Sunshine Regiment, as discussed by Vaniver, here:

As he's explained it to me, it sounds like it would need to be part of the code. From the outside, it would need to be a button on each post that would flag it as needing attention from a member of the SR. I feel like the flag should be visible to everyone, so that if things are getting out of hand, it can be put on pause until the SR takes a look at it, but it should not reveal publicly who flagged it. But maybe there is a better system for handling visibility and anonymity.

From the inside, it would need the features that Vaniver described, namely an issue-handling system for all the members of the SR to keep track of who's taking care of what, and which posts need attention. I'd think that SR should know who flagged a post, but maybe it could be anonymous to them as well.

(Or, maybe this has already undergone a more thorough discussion behind the scenes, in which case, you can just take this post as a vote in favor of SR support.)

Comment by grothor on Fact Posts: How and Why · 2016-12-12T05:52:50.208Z · score: 6 (5 votes) · LW · GW

I took a course in graduate school in which I interpreted a series of assignments as doing basically this (instead of something much more boring), but a bit less quantitative and a bit less focused on a single question. I found it to be so enjoyable that I spent entirely too much time researching things like trash-fired power plants and the problems associated with moving 400-ton power transformers around the country, and not nearly enough time doing actual science for my dissertation. The papers would need a little rewriting to be made into blog posts, but they're short and I should be able to make most of them work.

Or I could just learn more cool shit and write new ones.

Comment by grothor on Open thread, Sep. 14 - Sep. 20, 2015 · 2015-09-15T23:19:48.728Z · score: 2 (2 votes) · LW · GW

This sounds a lot like the theory of crystallized vs fluid intelligence:

As far as I know, by most any commonly used metric, both of these will increase well beyond four years of age. Vaniver mentions 15 years old, and I recall 19-20 years old being the number given for maximum fluid intelligence in the psychology textbook I had in undergrad.

Comment by grothor on Open thread, Sep. 14 - Sep. 20, 2015 · 2015-09-15T22:59:35.881Z · score: 8 (8 votes) · LW · GW

A while back, I was having a discussion with a friend (or maybe more of a friendly acquaintance) about linguistic profiling. It was totally civil, but we disagreed. Thinking about it over lunch, I noticed that my argument felt forced, while his argument seemed very reasonable, and I decided that he was right, or at least that his position seemed better than mine. So, I changed my mind. Later that day I told him I'd changed my mind and I thought he was right. He didn't seem to know how to respond to that. I'm not sure he even thought I was being serious at first.

Have other people had similar experiences with this? Is there a way to tell someone you've changed your mind that lessens this response of incredulity?

Comment by grothor on Stupid Questions September 2015 · 2015-09-03T21:13:23.405Z · score: 3 (7 votes) · LW · GW

Should I put my elephants in RAID 5, or should I just go with RAID 0, since they never forget?

Comment by grothor on Stupid Questions August 2015 · 2015-08-05T21:40:14.374Z · score: 3 (3 votes) · LW · GW

I will admit that when I wrote that, I was going off of blurry memories of seeing test scores. I will also admit that I kind of regret introducing the topic the way I did. I wanted to convey that I was comparing people who were both similarly removed from me culturally, but were from populations that would generally have different average intelligence from each other.

In that description, I was referring to literally just "some person who said they are in the fashion industry". This includes fashion designers, accountants, HR people, photographers, janitors, (materials engineers? computer graphics engineers?) etc. But sure, let's go with fashion designers.

Using IQ <==> SAT/GRE conversion tables, if you look up test scores for entering visual arts majors (I think that's what a college-educated fashion designer would study?), they average about 115 IQ, whereas GRE scores for entering psychology PhDs predict about 125-130 IQ (this one's hard, because I can only find "scaled" composite scores, rather than raw composite scores). This is about a one standard deviation difference.

I mainly believe in using SAT and GRE scores as a proxy for IQ because Scott Alexander believes in this enough to pay attention to it on the LW census. Also, I have skimmed some literature on it. I've not examined it carefully, and I'm interested to hear dissenting opinions.

This seems like clear evidence that your average college-educated fashion designer has a higher than average IQ, by a full standard deviation. Evidently, your average psychology PhD student (at the two competitive schools I looked at) has an IQ nearly a full standard deviation above that. Although what I said looks like the kind of thing someone would say if they thought fashion designers were stupid, that wasn't my intent.

Comment by grothor on Stupid Questions August 2015 · 2015-08-02T20:21:52.535Z · score: 2 (2 votes) · LW · GW

People who otherwise aren't intelligent often have somewhat smart things to say within their domain.

Right! And this is why I tried to get her talking about fashion. I think your suggestion of asking more specific questions is very helpful. I'll definitely try that next time I'm having trouble with the more generic "tell me about your expertise" type questions.

Comment by grothor on Stupid Questions August 2015 · 2015-08-02T19:45:37.730Z · score: 4 (4 votes) · LW · GW

After trying to imagine a way this would fail badly, I think you should make sure that whatever you do, you can remove it quickly. It's common for homemade electronics to get hot or catch fire, and you don't want to have any trouble getting if off your head if that does happen.

Comment by grothor on Stupid Questions August 2015 · 2015-08-02T19:37:16.741Z · score: 4 (4 votes) · LW · GW

What do you mean by "hard"? Difficult? Frustrating? Boring?

For a variety of reasons, I'm hesitant to share a specific example, but here is an exchange from the conversation I had recently:

Me: To me, the fashion industry is this black box that has people in it, and clothing comes out of it

Her (surprised, confused): It's not like that at all!

Me: What I mean is that I don't know anything about how it works, except that it involves people who design clothing, and then somebody buys it

Her (still confused): Yeah...

<at this point I decided trying to get her to tell me about it wasn't going anywhere, so I moved on to attempt at embarrassing my friend who was standing nearby, who then got lots of unwanted attention from her>

So I guess it's mainly frustrating or boring?

Comment by grothor on Stupid Questions August 2015 · 2015-08-02T19:16:08.705Z · score: 3 (3 votes) · LW · GW

I didn't mean to suggest that being in the fashion industry implies that someone is unintelligent. I've known plenty of smart people in industries that are not traditionally thought of as being full of smart people. For this reason, I usually approach a conversation assuming that someone is good at something they do, has thought about it deeply, and has something interesting to say about it. It's usually much easier for me to tease this out with smarter people.

Comment by grothor on Stupid Questions August 2015 · 2015-08-02T17:00:51.068Z · score: 6 (6 votes) · LW · GW

I work with infrared lasers, and the main safety advice I will give you is that 850nm light will look very dim, even if it is very bright. So be careful about shining it in your eyes, because how bright it looks is misleading. That said, it does take a very bright source of visible or IR light to actually damage your eyes.

Comment by grothor on Stupid Questions August 2015 · 2015-08-01T23:46:49.204Z · score: 8 (10 votes) · LW · GW

I was recently at a bar with some friends, most of which are from the same physics PhD program as me. We had a discussion about how hard it is to spend all your time around unusually intelligent people, and then go out into the real world and have conversations with normal people. It seems to be intelligence-related, because it's usually much easier to have a conversation with, for example, a psychology grad student from Singapore than with a fashion designer who lives in the same city as me.

Is this just because we have no practice talking to people of average-ish intelligence?

Is it because intelligence gaps are inherently difficult in social settings?

Is there some factor other than intelligence that's causing this?

Are we just socially inept?

(Is this more of an open thread question or stupid question?)