## Posts

Stupid Questions August 2015 2015-08-01T23:08:49.398Z · score: 7 (8 votes)

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

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: 10 (6 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

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

-Duration

-Time of day

-Eating before or during the ride*

-How fatigued I am from the day before**

-Average Power

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

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.
3. Browser on a desktop. Occasionally smartphone.

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

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 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.

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: https://en.wikipedia.org/wiki/Geometric_series

The proof (derivation?) is here: http://imgur.com/vSfABHk

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:

http://lesswrong.com/lw/o5z/on_the_importance_of_less_wrong_or_another_single/di1g

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: 3 (3 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: https://en.wikipedia.org/wiki/Fluid_and_crystallized_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?)

Comment by grothor on Rationality is about pattern recognition, not reasoning · 2015-05-28T07:07:22.066Z · score: 2 (2 votes) · LW · GW

I do not think the entire post was too long, but I do think reading the short version first was helpful. It's sort of like reading an abstract before diving into a journal article. If nothing else, it helps people who are uninterested save some time.

People who agree with you don't need to be convinced. People who disagree with you aren't going to be swayed by your arguments.

I'm not convinced this is true, but regardless, what about people who neither agree nor disagree? To a large extent, explaining why your viewpoint is right is exactly the same thing as explaining in detail what your viewpoint is.

Comment by grothor on Stupid Questions February 2015 · 2015-02-05T00:21:44.346Z · score: 4 (4 votes) · LW · GW

An update:

I decided to test the "not fun" part of the cost, by doing some cleaning and really asking myself how I felt while I was doing it. The answer was "not bad, almost relaxing". So I will try to update my model.

Comment by grothor on Stupid Questions February 2015 · 2015-02-05T00:19:00.938Z · score: 4 (4 votes) · LW · GW

Ah, okay, this helps a lot.

The issue is that, normally, there is a sharp transition from "enough clutter to feel messy and be hard to find things" to "clean enough that I can find things and it doesn't feel cluttered". This transition is in the last 30 minutes or so of the 3 hours. This means that:

on day 1 collect all things and put them into a temporary basket, and on day 2 take a few random things from the basket and put them where they belong.

will help solve the first half of the problem (feeling cluttered), even though it won't help as much with the second half (finding things). The trick will be to actually go back and unpack the temporary clutter storage space. I expect this won't be too hard, since I will be reminded every time I need something that is inside of it.

Comment by grothor on Stupid Questions February 2015 · 2015-02-05T00:12:31.623Z · score: 1 (1 votes) · LW · GW

Yes, this is what I try to do, and it is what I am able to do for, typically, a couple months at a time. Having someone else remind me that this is better than three hours all at once is good though. For some reason, I find myself slowly ignoring this advice from myself if I don't hear it from somewhere else every now and then. (avoiding this problem might be another good "stupid question"...)

Comment by grothor on Stupid Questions February 2015 · 2015-02-03T19:07:31.518Z · score: 1 (1 votes) · LW · GW

Yes, I've read that. Thanks for the reminder.

I think I'm having trouble with the 'expectancy' part of the equation. That is, I know that I will fail to complete the task now. Or, maybe you would say that the immediate value is almost zero.

Comment by grothor on Stupid Questions February 2015 · 2015-02-03T18:42:38.825Z · score: 4 (4 votes) · LW · GW

I have this issue with motivation. I need to clean my house, but I have a difficult time getting myself to do it, unless I think I can finish it all at once. For example, based on past experience, it takes me around three hours of focused effort to get things from where they are now to satisfactory, but I only have ninety minutes. While I could get half-way there now, and finish up sometime later in the week, I imagine myself working hard for 90 minutes, and still having a messy house. Then I do something else instead, unless I'm in a state where cleaning seems less unpleasant than usual.

Does anybody have advice for combating this problem?

(edited for a typo)

Comment by grothor on Open thread, Jan. 19 - Jan. 25, 2015 · 2015-01-21T22:05:24.201Z · score: 2 (2 votes) · LW · GW

I am taking a graduate course called "Vision Systems". This course "presents an introduction to the physiology, psychophysics, and computational aspects of vision". The professor teaching the course recommended that those of us that have not taken at least an undergraduate course in perception get an introductory book on the subject. The one he recommends, which is also the one he uses for his undergraduate course, is this: http://www.amazon.com/Sensation-Perception-Looseleaf-Third-Edition/dp/0878938761 Unfortunately, this book goes for $60-75 for used loose leaf, all the way up to$105 for new hardcover. I'd rather not pay that, unless I can get an independent recommendation for it, or for some other book on the subject.

Does anybody here have a recommendation? Are there good course notes available on the web somewhere?

Comment by grothor on 2015 Repository Reruns - Boring Advice Repository · 2015-01-10T02:41:55.109Z · score: 4 (4 votes) · LW · GW

Delayed response is also great to cool off heated discussions.

I've had this experience as well. Usually a five to ten minute wait is long enough for me to chill out and say something less inflammatory when things start getting bad.

Comment by grothor on Exams and Overfitting · 2015-01-08T19:15:28.671Z · score: 7 (7 votes) · LW · GW

I used to teach physics to pre-med students (a nearly-identical situation to [2] in the original post). I tried to write my exams so that simply memorizing a large set of very specific algorithms for solving a problems wouldn't work, but nobody would have to be very clever in order to get a good grade.

In addition to this, I looked at the course material and asked "Is there anything thing on here that a doctor really needs to know?". I decided it was good for doctors to know how half-lives work, since this is important for things like drug dosing, as well as probably other things I don't even know about (since anything who's rate of decay is proportional to it's value will behave the same way). So, I explained to my students that a discharging capacitor was mathematically identical to the way that some drug concentrations decrease over time, and that there absolutely, positively would be a question about it on the exam. I didn't say anything else very specific about what would be on the rest of the exam. That exam had one question about a discharging capacitor, followed by a second question that was the same as the first, but reworked in terms of drugs. Most students got the first one right, but fewer got the second.

I think that part of my distaste, as an instructor, for students knowing a lot more about what is on the exam was that I wound up talking a lot more about the same things, and it got boring.

Comment by grothor on Exams and Overfitting · 2015-01-08T18:52:23.288Z · score: 1 (1 votes) · LW · GW

I think the argument is that it is desirable for the optimal strategy for learning to be very similar to the optimal strategy for getting a good grade. Greater information about what is on the exam increases the difference between the two.

Comment by grothor on 2014 Survey Results · 2015-01-06T17:18:13.880Z · score: 0 (0 votes) · LW · GW

Literally every group had at least one member who supplied a P(God) of 0 and a P(God) of 100.

Okay, I'll bite: What does someone mean when they say they are Atheist, and they think P(God) = 100% ?

Comment by grothor on 2014 Survey Results · 2015-01-05T01:02:30.065Z · score: 0 (0 votes) · LW · GW

I would expect for asexuals to be overrepresented

Why do you expect this? It seems reasonable if I think in terms of stereotypes. Also, I guess LWers might be more likely to recognize that they are asexual.