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Dirac_Delta00

I'd like to solicit the help of physicists here.

I am in the process of watching Professor Walter Lewin's MIT lectures on Electricity and Magnetism. In Lecture 20, during the first fifteen minutes, Prof. Lewin criticized many textbook authors for misapplying Kirchhoff's rule when analyzing LR circuits, and clarified that Faraday's Law should be used instead. My study partner insisted that Prof. Lewin was wrong, and that Kirchhoff's rule applied in this case because the inductance came from within the circuit itself.

I would really appreciate it if anyone here could help me understand (with linked sources if necessary) whether Kirchhoff's rule is applicable here. If not, why? Can you explain it in a way that would make my study partner understand it?

Thank you in advance for all your help!

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[anonymous]00

Dr. Lewin's technically correct (which is the best kind of correct), but I doubt it much matters. Did you look at the lecture supplement? He gives a lot more detail there.

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[-]Qiaochu_Yuan80

There seems to be a pretty sharp lower bound on how cheap a living situation (e.g. rent on an apartment) can be in the parts of the United States I'm familiar with. I would have thought that there would be demand for cheap-but-bad housing on the part of people with low income. Here are some hypotheses I've come up with for explaining this, and I'd appreciate anyone who has relevant knowledge commenting if I'm on track:

  • There is in fact very little such demand in the US because people who can afford any kind of rent at all have grown accustomed to a certai
... (read more)
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[-]palladias120

There's also zoning laws. For instance, I live in DC, where there's a height cap on buildings, which makes it impossible to build towering, cheap, apartment buildings. (much to my sorrow).

That zoning law exists to keep buildings from blocking views of the Capitol, but a lot of other zoning laws exist exactly to prevent cheap apartments, because the people active in the zoning process don't want to live near the kind of people who would live in cheap apartments.

Robert Moses, from my home state of NY, is particularly famous for this kind of things. In addition to zoning, he also made sure that buses weren't allowed on some Long Island roads, or that bridge overpasses would be too low to fit buses under, to prevent people who rely on public transportation from traveling to certain neighborhoods and beaches.

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3Douglas_Knight
Height caps are overrated. Paris is five times denser than DC, but I believe that its height limits were stricter in the 20th century.
[-]gwern100

The cost of complying with health and safety regulations makes it too expensive to price rent below a certain amount even at the worst the rental situation is legally allowed to be.

There's also zoning and other issues, and subtler ones like licensing of construction trades, etc. But this seems to be a big part of the story. From last year http://www.psmag.com/navigation/politics-and-law/how-the-trailer-park-could-save-us-all-55137/

By any name, they are the largest source of unsubsidized affordable housing in the country. There are seven million manufactured homes housing 18 million people. In some counties they make up 60 percent of dwellings. Approximately one out of every 12 Floridians lives in a manufactured home. Units built since 1976, when the Department of Housing and Urban Development started regulating their construction, can last as long as site-built homes when they’re well built and maintained. Yet they cost far less: $41 per square foot versus $85 per square foot and up. At least one study, from the University of Illinois-Chicago, on trailer parks in Omaha, Nebraska, found that crime rates in mobile-home parks are the same as the rest of the community; the parks d

... (read more)
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8Douglas_Knight
Not paying rent is the least of the problems with bad tenants. There is a long tail of risk, such as destroying the building.
7Barry_Cotter
The middle class would prefer that people be homeless than that they have permanent dwellings that do not reach their standards. None of your explanations is correct but the second comes closest. See Flophouse. I believe Matthew Yglesias has written on this and there's a commenter on slatestarcodex, St. Rev, who may or may not have a blog, who's homeless.
6Dagon
* The opportunity cost of the land may be higher than you think. How far from a major population area are you looking? * Transaction costs (an expansion of your third point) are higher than you think. Do an estimate of what it would take for you to set up a group home in the areas you are willing to live. If you're lucky, you will be able to find partners and get it going for a bit under going rental rates. If not, you'll learn a lot and be able to report back here.
5[anonymous]
What do you mean by "bad" housing? One possible reason is that many of the relevant aspects of good or bad housing are governed by building codes (plumbing, HVAC, bathrooms, room size, etc.) which put a (often high) lower bound on how cheap a building can be built. In addition, the organization of the construction industry (many specialized subcontractors) means there's a fairly high fixed cost for any new construction. While this mostly applies to new construction, it can apply to existing buildings as well.
-7mickytallor
4Nornagest
You may be looking in the wrong places. SRO arrangements are still a thing, albeit a declining one, but as far as I can tell they don't get advertised anywhere a middle-class tenant would find them.
4[anonymous]
What parts are you familiar with? This makes a drastic difference.
0knb
You also have to take into account public housing projects and rent assistance programs.
[-]polymathwannabe80

How do I organize a LW meeting in a city (and perhaps the entire country) where I strongly suspect nobody else visits LW.com?

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[-]philh180

Pick a date, time, and location that seems sensible. Post a meetup. Say "I'm flexible about details, if this point in spacetime doesn't work for people". At the specified time, show up with something identifiable, and a book or some work that you can do to keep you occupied for, say, two hours in case nobody shows up. Hope somebody shows up.

Or feel free to say "I will only be there if I get at least N replies", where my own preferences would place N at one or two but YMMV. That reduces the probability of being bored and alone, but also reduces the probability of successfully meeting someone.

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[-]Viliam_Bur140

If you wanted low-level technical details, this is how I do it:

I have a phone number to a cafe, where I already did some meetups, so I call them to reserve a table for me on Monday from 18:00. They have no problem with it, even if I say "I am not sure how many people will come, at most 10 but maybe much less", because on Mondays they are half-empty anyway.

When I did this the first time, I used google and recommendations from my friends about nice places in the city. Then I visited personally (to see the place, and to be able to negotiate in person) and asked whether it would be okay to have a table reserved there. -- I specifically emphasised that most participants will be students who don't have much money and just want to talk, so they shouldn't expect a big revenue from this; and I asked whether that would be acceptable. (It's better to have a feedback in advance than a misunderstanding later.) -- Then I picked a Monday cca 2 weeks in future.

I post an announcement on LW, and also to the local LW mailing list. Sometimes I send personal e-mails to people I think could be interested. (Mostly they don't come, but sending the e-mail is so cheap and sometimes they come, that... (read more)

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9Viliam_Bur
There are two problems here: (1) Increasing the visibility of LW among minds which could be positively influenced by it. (2) Coordinating the already interested minds to meet at one point in the timespace. You asked specifically about the latter, but I want to make it explicit that the former is a meta-strategy for the latter. The more people know about LW, the easier it is to get some of them to the meetup. (These is a chance -- although I wouldn't rely on it -- that with popularity big enough, someone else would organize the meetup.) As a data point, the first meetups in Slovakia had between 4 and 6 people. And even that was because there were already 2 organizers (me and my girlfriend, and she did it partially to make me happy), and at that time there were no regular meetups in neighbor countries, so we regularly had one or two visitors from other country. It took more than a year to create a relatively stable community of about 10 local people. And I had to make some trade-offs; for example a few of them are not fluent in English, so we speak in Slovak, which excludes the potential foreign visitors. I am saying this to prepare you not to be disappointed by smaller participation. On the other hand, there are a few possible strategic moves I have ignored so far (such as doing a LW presentation at a local university), so a better strategy could possibly bring higher participation.
[-]ThisSpaceAvailable50

Can anyone explain the Olympics' tournament system to me? Team A beats Team B and advances to the finals. Team C beats Team D and advances to the finals. Team A beats Team C. Team B and Team D now play for third place, and Team B wins. Team A is awarded the gold medal. Team C is awarded silver. Team B is awarded bronze. What's up with that? Team B and Team C have the same win/loss record. They both beat Team D, and lost to Team A. Why does Team C get the silver?

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9Crude_Dolorium
I've wondered about this too. I once tried to organize a round-robin tournament, and discovered that all the other players preferred single elimination despite its vulnerability to noise and lack of a meaningful second place. In the ensuing argument, I discovered that they do know about problems like this, but they don't care, for two reasons: 1. They don't care much about accuracy. Tournaments ostensibly rank teams by quality, but they're used mostly as ritual contests: the audience wants to know who won, not who would most likely win. 2. They don't like complexity or novelty. They're suspicious of any design they don't understand, because they're afraid it might be gamed, or might have perverse incentives (e.g. where losing a match helps you win the tournament), and because they want everyone, even the dumb jocks, to understand the rules.
3V_V
from Wikipedia
3RowanE
Well, on the surface level, Team B lost their first match and won their second, while team C won their first match but lost their second, so clearly order matters. On the more meta level, a format optimised for selecting one winner has been poorly adapted to the task of selecting three winners and ranking them. Adjusting the format to fairly select silver and bronze would add complexity and cost and time, and apparently not enough people care enough about fairly selecting silver and bronze for this to have happened.
0Metus
[Delted: Didn't think about the question properly]
[-]moridinamael40

I'm trying to figure out if I

  • have an average memory, but the availability heuristic biases me toward finding examples of other people remembering things that I don't remember, or

  • I have a below average memory.

I guess I think this is a stupid question because how are you supposed to help me answer it via online message board? But it seems like kind of a typical problem to have, being unable to tell the difference between "I'm performing fine but I disproportionately notice my mistakes" and "I am actually performing poorly."

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6Qiaochu_Yuan
What do you plan on doing with an answer to this question?
3Sherincall
This seems easily testable. Though I cannot recommend any, I'm sure there are online memory tests that let you know how you performed relative to all the other subjects. Maybe not good enough, as there is a selection bias in the sample of people who take those tests, but it will give you some info. However, I think that you have an above average memory and are only noticing this because you usually hang around people who have above average memory as well[1]. Perhaps a more useful test would be getting your friends to take the test as well and compare the results. Maybe ask on LW for subjects? I'd participate. [1] Assumptions: * You have an above average IQ. I a priori assume this of all LWers. * There is a positive correlation between IQ and memory. A quick search gives results in favor of the assumption, but I didn't dig deeper. * You hang around people of similar IQ.
1ChristianKl
I think most of them test short term memory. In a lot of cases we care about long term memory.
0hyporational
Memory is a complex process and there are different kinds of specialized memory modules in the brain. Have you noticed that you have a problem with specific kinds of memories? Do you have problems with attention? You might not encode the memories in the first place.
0ChristianKl
There are a lot of different kinds of memory. You might have a good memory for some facts that you care about and a bad memory for facts that you don't care about.
0mickytallor
Memory is always related with the interest in the specific subject. A survey suggest that people remember each and every detail of their favorite thing. For example, men always know more about cars.
0[anonymous]
There are tests of working memory that you can seek out, if this really bothers you.
-2knb
Do you have many more memories of other people remembering things when you don't remember them than you have memories of things you remember that others don't remember?
[-]FiftyTwo40

Given the low probability of curing death in our lifetimes isn't psychological acceptance of death more likely to make one happy?

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6Ishaan
The anti-death argument you are implicitly referencing only states that "Death is bad", not "we have to feel negative emotions in response to death". There's nothing wrong with coming to terms with it, as in "this bad thing will probably happen to me, and I accept that it must be so". It's like if you lose a limb - its possible to come to terms with that even if it's clearly bad.
6RomeoStevens
If we end biological aging we still have accidents. If we end accidents we still have suicide. If we end suicide we still have the heat death of the universe. Making peace with death isn't a terrible use of time regardless of circumstance.
7Creutzer
Also, a pretty disgusting totalitarian regime.
6RomeoStevens
Or it is still an option but no one ever takes it because existing is universally awesome.
5pan
Along these lines, if we pretend there is actually a zero percent chance of curing death in our lifetime, how should we rationally act differently? Often people use the cliche 'if you were going to die tomorrow what would you do differently today?' as a thought experiment, seemingly implying (to me at least) that we're already living rationally for an ~80 year lifetime and that only changes in behavior should come from learning you have a very short time to live left. I often wonder if I too easily approximate ~80 years as infinity in my reasoning about life, and that I'm not appropriately taking into account an 80 year life span (or much shorter if you subtract sleep, how old you are now, and years of life you think you'll be healthy enough to have control over). TLDR: I think it's hard to reason about spans of time that are longer than we've experienced but shorter than infinity, and I don't know what to do about it.
8itaibn0
Your intuitive notion of how long a year is already takes into account time lost from sleep, so you shouldn't explicitly subtract that off.
3Viliam_Bur
Imagine a large paper divided into 100 x 100 squares. One of those squares, most likely at the bottom part of the paper, contains an invisible mark. Every day you remove a square. When you remove the one with the invisible mark, you die. (If you are a student, you have more expected days remaining, but you should be aware that they will be on average less useful than the ones you have now, because generally, as you grow older, you have gradually more duties and worse health. So you probably should imagine 100 x 100 days, even if you have more, to compensate for this bias.) Too much or too little? Think about the activities and plans you were doing recently, to calibrate yourself how many squares would each of them cost. (Include the days when you were too tired or too busy to do anything useful, because those days passed too.) This gives you an idea about how much can you do. Now think about the things you did 10 years ago; how happy you are you did them; how many of them do you even remember. This gives you an idea about how you will feel 20 or 30 years later about how you spend your time now.
1ChristianKl
I don't think that probability is low. But even if it would be low, not tormenting yourself with the idea that you will die is not the same thing as completely accepting death.
1Qiaochu_Yuan
Not if you think slightly increasing the probability of death being cured is more important than being happy. (I'm not saying I think this.)
0blacktrance
And if you think that being happy (as a result of psychologically accepting death) reduces the probability of death being cured.
[-]devas40

Okay, I believe I have a very stupid question I need to ask:

Why isn't there more research in progress on how to wake up people from cryonics? Or, rather, why aren't more people sticking hamsters and dogs under liquid nitrogen*, then trying to revive them and bring them back to "full life", and seeing if dear ole Spot remembers all the tricks we taught him?

If such things are underway, why aren't there more news and data on this?

*gross oversimplification is funny

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[-]gwern160

Who would be willing to fund this research? The cryonics organizations usually run at losses (membership and preservation fees do not pay 100% of expenses) and don't have the money for much research. And the public doesn't care - have you donated to the nearest available equivalents like the Brain Preservation Prize? If you haven't and are unwilling, then you have your answer.

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8[anonymous]
Because anything bigger than a cubic centimeter or two that you try to vitrify always comes out of vitrification full of massive cuts and chemical toxicity and ice crystals and leaky membranes to the point that calling it temporarily 'alive' is a stretch. This is not a problem with the revival process, but with the preservation process. Even freezing samples of cultured cells has a mortality rate.
3ChristianKl
Because cryonics is not simply about putting people under liquid oxygen. It also involve given people a highly toxic substance that prevent ice crystals from forming inside their brains. The substance does no harm if you are frozen is ice but if you would just try to revive people the substance would kill them. You need nanotech to remove it. Cryonics needs nanotech to revive patients. Currently there no good nanotech for doing so. It makes more sense to wait till we have good nanobots and then attempt to revive organisms.
5Pfft
Well, but for sufficiently small things one may be able to get by without too toxic cryopreservants? Famously, things like embryos and even rabbit kidneys have been frozen and then "revived". If this could be scaled up to e.g. a mouse (something which is big enough to have nontrivial memories), that would resolve lots of worries about there not being enough information preserved in a vitrified brain.
1[anonymous]
You can freeze nematodes and water bears fairly easily. Notably both of these are evolved to survive dessication and freezing in their normal life cycle and have their largest dimension on the order of one mm. Its a bit of a stretch to call what some frogs can do naturally in the outdoors 'freezing' but again, massive evolutionary pressure. If you try to freeze a complicated structure bigger than a few cubic centimeters that isn't the ridiculously vascularized and quite small and very homogenous in terms of water content rabbit kidney, you come up with something that is so damaged by the freezing process that it falls apart physically and chemically upon unfreezing. The unfreezing part is not the limiting factor, because there just isn't a paused functional organism left behind by the freezing process.
0InquilineKea
What about the wood frog?
2Alsadius
Because it's a very small industry, and nobody has the money for it?
2DanielLC
I'm told that there have been brains with no activity that have been revived, showing that that at least isn't where all the information is stored. It doesn't prove that cryonics is possible, but it disproves the most obvious reason why it wouldn't be.
5[anonymous]
Indeed, no neurologists propose that activity is important for anything but short-term memory and, of course, all normal functions. Memory and what a bit of tissue is capable of come from physical structure.
[-]solipsist30

Meta

This post is part of an experiment aimed at relieving pressure on the open thread. If you have any comments on this thread itself, leave them here.

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[-][anonymous]20

(Why) should I follow my moral intuitions?

(Inspired by Yvain's Consequentalism FAQ.)

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[-]Larks20

I currently use Mnemosyne 1.2.2, and have a deck of over 2,000 cards, including pictures, html, LaTex, etc. Ideally I'd like to be able to review these on my android phone, but whenever I've tried this, I've run into sufficient problems that I've given up.

  • I tried upgrading from Mnemosyne 1 to Mnemosyne 2, but a large fraction of the cards were damaged in the translation (for example, I'd often made double-sided cards, then deleted one side, in Mnemosyne 1, but Mnemosyne 2 was not happy about this).
  • I've had trouble getting Mnemogogo to work, and it seem
... (read more)
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0gwern
I occasionally deleted one half a of a double-sided card and I do not recall any odd behavior when I upgraded to 2.x... Have you tried exporting your cards with learning history and importing them to a 2.x installation? Or brought this up with Peter?
[-]Adam Zerner20

Is there a formal fallacy of taking something that's overrated, and concluding that it sucks? (Because you overreact to the fact that it's overrated)

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8Locaha
We can call it Hipster Fallacy, maybe?
3Viliam_Bur
Seems like a specific case of reverting stupidity (but that's not a formal name).
1polymathwannabe
Perhaps specific examples could help. Can you name something that is clearly overrated and clearly doesn't suck?
4Adam Zerner
Good point! Someone who thinks that looks are overrated, and then concludes that they don't matter at all. Someone who thinks that a basketball player is overrated, and then concludes that he sucks.
1polymathwannabe
Most of my friends are big fans of heavy metal, but I abhor it ardently. I can match your example by saying heavy metal is unduly overrated, plus I do happen to think it sucks. One part of my head feels inclined to say that a judgment of sucking is a necessary component of the judgment of overratedness. However, I also think Finding Nemo is overrated, but I don't think it sucks. This leads me to think there are degrees of overratedness; i.e. my tastes place Finding Nemo on a much higher position of enjoyability than all of heavy metal. My friends who love heavy metal will accuse me of committing your proposed fallacy; they could say I'm not justified in saying heavy metal sucks just because it fails to please me. But if someone else says Finding Nemo sucks, I won't blame them, even if my dislike for it doesn't go that far. It's difficult to name a formal fallacy of personal tastes. It's one thing to detect a flaw in matters of true/untrue, but quite another to say that there can be flaws in matters of like/dislike.
[-]Darklight10

Should I take a proper IQ test?

In the past I've only ever taken those questionable online IQ tests, and managed to get something like 133 from them, but they're obviously not the most reliable source.

The only other really IQ-like test I've ever taken was the Otis-Lennon test in grade 4, which I only got 114 on. But I also remember misunderstanding the instructions and thinking I wasn't allowed to skip questions, so I only actually answered 50 of the 75 questions on the test (I got stuck on question 50 for a long time).

I also more recently managed exactly ... (read more)

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1Nornagest
I wouldn't bother. If you're old enough to be taking the LSAT, a high IQ score won't be opening any worthwhile doors for you; at a younger age you might have been able to leverage it into admission to some useful programs, but now it's only good for bragging rights. And it's not something that it's socially acceptable to brag about in most contexts. (I don't remember ever mentioning mine past high school, except on the mostly-anonymous LW surveys.)
[-]Viliam_Bur10

Which are the most beautiful mathematical or physical equations?

I am interested in the elegance of the equation itself (not its visualization, e.g. the Mandelbrot set). Yeah, I know that there is a difference in opinions, but I hope there will be some correlation among experts. I would like to have, let's say, 5 candidates.

This is a specific example, and a very good candidate, IMHO:

e^(i π) + 1 = 0

I would like to have about 5 equations, not just one, so even if you agree with my choice, please post even the equations that seem a bit less impressive, but the... (read more)

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4Stabilizer
This equation blew my mind.
3Squark
Off the top of my head: Physics: * Einstein-Hilbert action: * Expectation values using Feynman's path integral: * Yang-Mills Lagrangian: * Deformation quantization (not sure what's the proper name for this, maybe Dirac's rule): * Fundumental thermodynamic relation: Mathematics: * Stokes' theorem: * Riemann's functional equation: * L'Hopital's rule: * Taylor's series: * Lefschetz-Hopf theorem (unfortunatelly couldn't find one image of both sides of the equation):
0Viliam_Bur
Thank you!!!
2Richard_Kennaway
For a right-angled triangle, x^2 + y^2 = z^2.
2gjm
Are you interested in elegance given physical relevance? For instance, Maxwell's equations aren't anything all that special in themselves, but when you discover that they explain approximately all of electricity, magnetism and light it's a different matter.
0Viliam_Bur
I didn't think about this part, because originally I was only thinking about math. Thank you for giving specific examples, so I can test my intuition to them. Uhm... I'd say that "Δ . B = 0" doesn't trigger my feeling of awesomeness, however important it may be. Even "E = m * c^2" doesn't, and that has a lot of applause light connected with it. They are just too simple; they feel like "a + b = c". On the other hand, I realized that if I don't know what the equation means, I can't decide whether it is good enough. So the meaning is a part of the utility function, but mathematical elegance is another part (the feeling of "oh, this is really equal to that?" like when the pieces of puzzle suddenly fit together) -- and I want the equations that satisfy both criteria. Squark's examples are already great enough and probably all I need, so if you had some specific examples in mind, please post them here, but otherwise I already have what I wanted.
0bramflakes
The tau version for Euler's Identity is slightly more elegant. e^(iτ) = 1
0A1987dM
S = k ln W
[-]dunno10

If suffering has far greater dis-utility for you than happy living has utility, is it logical to conclude that it'd be a good thing if the universe ceased to exist, thereby preventing all future suffering at the cost of all future life?

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6Baughn
No, since there may be far more happy living than suffering. Not on its own, at least.
3Creutzer
You might want to look at the writings of David Benatar. He's a professional philosopher who argues something similar in spirit. His position it that it would be better for there to not be (and never have been) any sentient life. He is not as crazy as this may sound; the problem is just that he has one premise that is totally intuitive to some people while others completely fail to see its appeal, and there's no real reason for or against accepting it other than intuition. The shortest thing to read would be his paper "Why It Is Better Never to Come into Existence". He also has a book titled "Better Never to Have Been: The Harm of Coming Into Existence".
2MugaSofer
No. Not purely from that knowledge about your utility function, anyway. Unless suffering has infinite disutility, then enough happiness would outweigh all the suffering in the world. If we reach a Good Future, then it would be worth it even if the average modern human has negative utility - which seems far from obvious itself, even given the premise; most human lives could still experience sufficiently more happiness than suffering.
1RowanE
Only if you also do not expect there to be enough happy living to outweigh the amount of suffering.
0dunno
This just doesn't seem right. Perhaps no amount of happy living outweighs suffering beyond a certain amount.
3RowanE
Well, that sounds obviously wrong - it would mean you could start with a universe you liked, scale up the population without changing average quality of life at all, and end up with a universe in which you want to destroy all life.
0dunno
What makes this obviously wrong? I mean, aside from preferences, why would it not make sense to start with a universe in a current state you like and end up with a state you dislike?
0RowanE
The universe you dislike is in the same state as the one you like, there's just more of it.
1Creutzer
I think you're talking past each other. Rowan is assuming the amount of happiness and suffering to be distributed across several people, where adding another person with the same suffering/pleasure ratio shouldn't change anything, and dunno is, I believe, talking about a single person's perspective where, once you've reached a certain amount of suffering, it might be impossible to outweigh it.
1Dagon
In that case (which I believe is not true for almost any modern human, so this is a purely theoretical answer), it's logical to conclude that it'd be good for you to cease to exist. In order to prefer that others so cease (assuming you're a utilitiarian), you'd need to believe that every individual has a similar weighting.
0dunno
If I ceased to exist there would still be people that suffered without a choice. Ceasing to exist wouldn't change this while if everything ceased to exist, it'd change.
0Alsadius
All that implies is that we ought to tolerate suicide. Those with negative net value attached to living can reset it to zero pretty easily.
[-]Scott Garrabrant10

Is there an easy way to make my phone alert me when there is a new discussion or main post? What about a new response to my comments?

Reply
6palladias
I haven't used it, but I think If This Then That might be helpful. It's a way to link triggers (like an RSS feed) with other actions (like a text).
0Douglas_Knight
The keywords to search under are "rss" and "feed." This is a format intended for computers to read and learn about updates to a website. There are feeds for main and discussion. I don't know any particular tools, but there are certainly ways of turning an rss update into an email or a text message. There are probably apps for your phone that make an alert when they notice something new in the feed, too. The inbox has a feed, too, but that link only works if you are logged in, which may be difficult to do in the feed reader.
[-][anonymous]00

How private are private PredictionBook predictions? Does there exist a moral system based on reciprocity?

Reply
1Lumifer
The Golden Rule is one: "Do unto others as you would have them do unto you".
0[anonymous]
Apparently it is, but it implies that everybody is basically the same person, which is rather dubious. Is it still a Golden Rule if I paraphrase "One should treat others as one would like others to treat oneself." to "One should treat others as they would like to be treated"?
0Lumifer
I think most (but not all) people will say "yes", but why would you care about a label as long as you're clear as to what you are saying?
0[anonymous]
:(
0[anonymous]
Apparently it is, but it implies that everybody is basically the same person, which is rather dubious.
[-]Dirac_Delta00

I'd like to solicit the help of physicists here.

I am in the process of watching Professor Walter Lewin's MIT lectures on Electricity and Magnetism. In Lecture 20, during the first fifteen minutes, Prof. Lewin criticized many textbook authors for misapplying Kirchhoff's rule when analyzing LR circuits, and clarified that Faraday's Law should be used instead. My study partner insisted that Prof. Lewin was wrong, and that Kirchhoff's rule applied in this case because the inductance came from within the circuit itself.

I would really appreciate it if anyone her... (read more)

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0[anonymous]
Dr. Lewin's technically correct (which is the best kind of correct), but I doubt it much matters. Did you look at the lecture supplement? He gives a lot more detail there.
0Dirac_Delta
I have, but my study partner insists that Prof. Lewin is wrong, and I don't know how to explain it in a way that would make it understandable to him.
[-]polymathwannabe00

I've been trying to wrap my head around arguments involving simulations, e.g. what to do if Skynet (replace with whatever AI you prefer to hate) threatens to torture a large number of simulations of you, etc.

Here is my stupid question: why can't we humans use a similar threat? Why can't I say that, if you don't cooperate with my wishes, I'll torture imaginary versions of you inside my head? It's not like my brain isn't another information processing device, so what is it about my imagination that feels less compelling than Skynet's?

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4Nornagest
I no longer find it totally implausible that imagined people might, if modeled in enough detail, be in some sense conscious -- it seems unlikely to me that human self-modeling and other-modeling logic would end up being that different -- but even if we take that as given, there's a couple of problems with threatening to imagine someone in some unpleasant situation. The basic issue is asymmetry of information. You might be able to imagine someone that thinks or even reliably acts like your enemy; but, no matter how good you are at personality modeling, they aren't going to have access to all, or even much, of your enemy's memories and experiences. Lacking that, I wouldn't say your imagined enemy is cognitively equivalent to your real enemy in a way that'd make the threat hold up. (Skynet, by contrast, might be able to reproduce all that information by some means -- brain scanning, say, or some superhuman form of induction.)
3tut
You can't simulate anything in the relevant sense. Personally I don't care about the threat you refer to even when it comes from skynet, but the thing that makes some people care is that the simulation contains all information that's in their conscious mind, and thus plausibly is conscious and suffers for real.
0TheOtherDave
My own thinking about this whole class of questions starts with: is the agent threatening this capable of torturing systems that I prefer (on reflection) not be tortured? If I'm confident they can do so, then they can credibly threaten me. Among other things, this formulation lets me completely ignore whether Skynet's simulation of me is actually me. That's irrelevant to the question at hand. In fact, whether it's even a simulation of me, and indeed whether it's a person at all, is irrelevant. What's important is whether I prefer it not be tortured. A lot of ill-defined terms ("person", "simulation","me") thus drop out of my evaluation. In principle I expect that a sufficiently capable intelligence can create systems that I prefer not be tortured, but I'd need quite a lot of evidence before I was actually confident that any given intelligence was capable of doing so. That said, the problem of evidence is itself tricky here. I expect that it is much easier to build a system I don't endorse caring about in the abstract, and then manipulate the setting so that I come to care about it anyway, than to build a system that I endorse caring about. That said, we can finesse the epistemic issue by asking a different question: is the intelligence capable of creating (and torturing) a system S such that, if I somehow became confident that S has the attributes S in fact has, I would prefer that S not be tortured? My confidence that humans have this ability is low, though (as above) in principle I expect that a sufficiently capable intelligence can do so. Certainly I don't have it, and I've never seen significant evidence that anyone else does. Have you?
[-]Dahlen00

"Is false when preceded by its quotation" is false when preceded by its quotation.

I feel stupid for this, but I can't quite wrap my head around it. Can somebody please ELI5? (I'm asking LW because it seems to have more than its fair share of math & logic whizzes.)

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0gjm
So first of all, a purely syntactic remark: this involves a rather unnatural construction, taking "X's quotation" to mean what you get by putting X in quotation marks. So far as I know, no one ever uses the word "quotation" in this way except when talking about Quine's construction (i.e., the thing we're talking about now). OK, let's proceed. The version of this I've seen is slightly different (and avoids Creutzer's complaint): So, let Q be the sentence-fragment "yields a falsehood when preceded by its quotation". Then for any sentence-fragment R we can construct a sentence ["R" Q], and what it says that ["R" R] is false. E.g., if you say ["foo" yields a falsehood when preceded by its quotation"] you're saying that ["foo" foo] is a falsehood. Now, of course in this particular case that's wrong because ["foo" foo] is just nonsense, not a falsehood. So ["foo" yields a falsehood when preceded by its quotation] is wrong. Or consider ["is a sentence fragment" is a sentence fragment]. That's true, so ["is a sentence fragment" yields a falsehood when preceded by its quotation] is wrong. So, in general, ["R" Q] is a sentence -- call it S -- saying what you get when you construct the possibly-a-sentence ["R" R] -- call that T -- and in particular claiming that it's a falsehood. That is: S says that T is false. Now, what happens when you let R=Q? Well, in that case S and T are both ["Q" Q] or, writing it out in full, ["yields a falsehood when preceded by its quotation" yields a falsehood when preceded by its quotation]. S says that T is false, but in this case S=T, so S says that S is false. In other words, it's an Epimenides-style paradox but without explicit self-reference. Instead we have a sort of self-reference by construction: we've got a sentence that says "Build a sentence according to such-and-such a recipe; the result is false", and it just so happens that when you do what it says the sentence you get is that sentence. This is quite closely analogous to how
0DavidS
The grammar of the sentence is a bit hard to follow. When I am presenting this paradox to friends (I have interesting friends), I hand them a piece of paper with the following words on it: I urge you to carry out the task. You should wind up with a paper that has the exact same words on it as the paper I gave you. If you believe that the statement on my paper is true, then you should believe that the statement on your paper is false, and vice versa. Yet they are the same statement! Assuming that you think truth or falsehood is a property of grammatical sentences, independent of where they are written, this should bother you. Moreover, unlike the standard liar paradox, the paper I gave never talks about itself, it only talks about a message you will write on some other piece of paper (which does not, in turn, talk about the original message) when you perform some simple typographical operations. Quine constructed this example to demonstrate the sort of subtleties that come up in order to invent a mathematical formalism that can talk about truth, and can talk about manipulating symbols, without bringing in the liar paradox. (To learn how this problem is solved, take a course on mathematical logic and Goedel's theorem.)
0Qiaochu_Yuan
Have you read the Wikipedia article?
4Dahlen
Yes, and I'm still not getting it. Hence the stupid questions thread.
0Creutzer
I suppse the intention is for this to be another version of This sentence is false, but it fails. The sentence (1) "Is false when preceded by its quotation" is false when preceded by its quotation. says that the string "Is false when preceded by its quotation" has the property of being false when preceded by its quotation. The sentence is, in fact, that string preceded by its own quotation. However, there is no paradox. The whole sentence (1) can be true, and then the italicised occurrence of the string "Is false when preceded by its quotation" is false. No problem there. Incidentally, it's dubious to ascribe "is false when preceded by its quotation" a truth-value anyway, since it's not a sentence, but merely a verb-phrase. One could change it to "yields falsehood when predicated of its own quotation". Then you get the sentence "Yields falsehood when predicated of its quotation" yields falsehood when predicated of its quotation, which looks more paradoxical. However, I'm not entirely clear that it really is a paradox, either. There might be some confusion there between predicates and strings that refer to predicates. It depends on how quotation in natural language really works...
[-]MarkusRamikin00

Polish (or Polish-speaking) people help me out here: do we even have a word for mathematical odds? I distinctly remember learning about it in math class, but I can't for the life of me remember what the old hag called it, bless her grumpy soul. And the fact that this page... http://en.wikipedia.org/wiki/Odds ...has all those equivalents in other languages, but not Polish, is starting to make me seriously fear that we just don't have a word for it.

While we're on the subject, what words would you use to differentiate "proof" from "evidence" in Polish? Seems "dowód" is the only thing we have...

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0Aleksander
While we're on the subject, what words would you use to differentiate "proof" from "evidence" in Polish? "Poszlaki"?
-1Tenoke
http://translate.google.com/#en/pl/odds I really hope I am missing something and this isn't a sufficent answer to your question.
3MarkusRamikin
Yeah, tried that, and none of these words seem to be it. The word "kurs" does mean odds but only in a gambling context; it also means "exchange rate" when applied to currencies, it's that kind of a financial word. I'm looking for what a mathematician would use. Different languages don't carve reality the same way (which is why I find wikipedia a better dictionary than the piece of relative uselessness that is Google Translate, because if I understand both articles then I can be sure I have the right word for my meaning), but I'm still sure such a word must exist because it's a specific thing in mathematics. That's why I posted in the dumb questions thread. ;) EDIT: Aha. "iloraz szans". Can't remember ever hearing this term, but at least I know now why it's not linked to from the English article - because Polish wikipedia in its wisdom decided it's not worthy of its own article, and buried this info in an article about logistic regression.
0tut
What word do people who bet on horses use? Is there a difference between mathematical odds and gambling odds (other than what things you talk about odds for?
0MarkusRamikin
I don't bet on horses, but I figure they'd use "kurs". And the word means more the relation between bets and payoffs than the mathematical probability of winning, so it kinda makes sense that it's a different word.
[-]pan00

This is probably a stupid question:

How is rounding error not a fatal flaw in brain simulation? Meaning, even if you could copy the workings of someones brain perfectly, it's presumably still a calculation done on some computer in some way. So even if you store the first X digits of every number in the calculation, it would at some point diverge from what the real brain did, even if it took a very long time.

Therefore is it fair to call that copy that 'person' or rather do you have to switch to speaking in terms of fidelities: that copy is Y percent the original person and diverges at a rate of Z percent every so many steps?

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[-]gjm130

Yes, the two will diverge. But then, so they would even without rounding error, on account of quantum mechanics.

Neither of them is "the original person" (you are not, now, quite the same person as you were a year ago). Both are, so to speak, descendants of the original person. There are many (apparently) possible descendants -- you never know what might happen to you, after all. A good enough simulation would be as much like one of those as they are like one another. (I suppose that's a definition of "good enough".)

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[-][anonymous]110

You don't even need quantum mechanics. The closest thing you can use to describe the way that cells actually function is 'noisy differential equations'. With emphasis on 'noisy'.

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5ThisSpaceAvailable
Since humans have a finite lifespan, if the point of divergence takes long enough, then it doesn't matter. And even if one wishes to simulate an immortal being, if one has unlimited resources, one can perform a sequence of simulations, each one twice as long as the previous.
0ChristianKl
Even an actually person diverges from who they are at 20 years of age to who they are at 40 years of age. Calling the person over that timeframe the same person means that you do allow some changes. As far as I understand proponent of uploading think that the brain will be simulated enough that the changes in the person will be as trivial as a few years of learning.
[+][anonymous]-50
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