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If time slows down proportionally, the closer to the speed of light you travel, does that mean that time has no existence to a light wave in a perfect vacuum? | I've been getting WAAAAAAY into the cool parts of science lately. Rewatched every through the wormhole episode, currently halfway through "Physics of the Impossible" by Michio Kaku, watched tons of episodes of Nova, and one question I haven't seen answered(yet), is whether time exists at all for a light wave travelling in a perfect vacuum? | Do you understand mathematical limits?
If you take the function, then yes the limit approaches "zero" or "no time".
**HOWEVER**, nothing moving at c can have a valid reference frame, because the equations are undefined at c.
So the answer is "light waves in a vacuum cannot have a reference frame", and also "as you get closer and closer to c, time slows down more and more to a complete standstill, but never gets there" | 22 | 47 |
CMV:There's no reason to wash your hands after going number 1. | For the record, I always wash my hands. But it is partly as a social courtesy. The other part is psychological. If I don't wash my hands, I "feel" like they are dirty.
That said, if you've only urinated, then your hands are not any dirtier than before you went to the bathroom. A man can pee and touch nothing more than his belt buckle. I assume most people are able to use the facilities and touch nothing more than toilet paper or clean skin. I say clean skin, because I feel like our hands are dirtier than most of our body. So I don't think they become significantly germier in the course of normal business.
I believe hand washing is 97% psychological. I think we do it because it makes us "feel" clean, and because if other people don't do it, we "feel" like they are unclean.
I'm not very interested in debating exceptions or fringe cases. I'm talking about the standard. I'm open to changing what I view as the standard. But basically, if you have an exceptional need to wash your hands, I don't believe that responsibility impacts my argument.
Edit: For clarity, my position is that urinating does not make your hands significantly dirtier. I think hand washing is a good habit as a separate issue from restroom use. I'm not likely to respond to further comments about the convenience of washing your hands while you happen to be by a sink.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Washing hands, in general, is a way to keep the spread of germs down. A typical person will go #1 3-5x each day. And if you just wash your hands each time you do that, you're washing off the germs you accumulated over the last few hours. So it's less about washing off germs you got in the 2min you were in the bathroom and more about taking advantage of the fact that you're near a sink and soap already so why not take a step towards general cleanliness. | 72 | 51 |
ELI5 Why does sunlight darken skin but lighten the colour of other surfaces? | Sunlight can breakdown the molecules that give things their coloring, lightening them. This works for objects because they are not alive, and so can't replace the destroyed color molecules.
You, however, are alive. Your body will actively choose to produce more skin pigment molecules if you get exposed to a lot of sunlight. It does this because the pigment protects you from the damage sunlight can do to you. | 86 | 27 |
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Is there any reason other than "for looks" that long hair on females became a social norm? | Is there any reason as to why females have almost always had long hair, at least compared to males, throughout history? Was there any kind of advantage this offered? Is male hair different than female hair? | Anthropology major here (graduating senior), long hair on women is a signal of reproductive health for women in western society. It is has links to youth and vitality, which are indicators of reproductive health.
A citation for clarity and accuracy
Hinsz, Verlin B., David C. Matz, Rebecca A. Patience. Does Women's Hair Signal Reproductive Potential?. Journal of Experimental Social Psychology, Volume 37:2 (2001), 166-172. | 38 | 47 |
Super-hydrophobic walls in Hamburg, Germany, reflect urine back at the evildoer. How does this work? | https://www.youtube.com/watch?v=uoN5EteWCH8
Apparently the product in question – a simple shelf product – is called Ultra Ever Dry.
To think they called it the *Peeback*. Wow. | Water forms hydrogen bonds, polar interactions, and dispersion interactions with stone that cause it to stick to the wall. The product is a mix of polymers and hydrocarbons and some other things like ketones that don't do hydrogen bonding and polar interactions to a high degree so don't stick to water.
When the urine hits the wall it as such bounces off like a ball bouncing off a wall, and hits feet. | 13 | 132 |
ELI5: How are living DNA and cells formed out of atoms and dust? | I always found it weird how atoms and dust can suddenly become life, and I know the right conditions are needed, etc. But how does rock dust or tiny little atoms suddenly "come alive"? or form a complex helix of DNA?
If it is made out of literal minerals and atoms, how come we're not as heavy-duty as them? How does DNA carry genetic information from nowhere? | There are theories about how life started, but we don't know for sure. Laboratory experiments with a mixture of chemicals in water have resulted in some rather complex organic chemicals that ARE part of life, but so far we have not observed an entire cell assembling itself and starting to "live".
Otherwise, we do chemistry by dumping 10^23 or more atoms of one kind into 10^23 atoms or molecules of another kind, and they react because atom energy levels are "better" if they complete their electron orbitals by joining with other atoms.
Cells, on the other hand, do chemistry internally atom-by-atom: the proteins function like little robots that literally assemble molecules together. Cellular function is extremely complex, but in simple terms, sections of the DNA (master recipe) get copied to RNA (recipes) and proteins get created or used to *do* what the instructions say, with other parts of the cell acting as "sensors" for "too little or too much" and to control the reactions.
The cell is a factory, basically. | 30 | 25 |
[Star Trek] Bridge officers = away team: Is this normal for the Federation? | You would think that on a large starship with hundreds of crew members, there would be dedicated, specially trained away teams. Sending the captain and/or next several officers in command down to the planet every week seems like an unnecessary risk for such vital crew members. Is this SOP for the Federation, or just on ships named "Enterprise"? | In normal situations, usually one officer, maybe two officers, would be sent down in command with a team of regular crew.
Of course, what you see in the history vids isn't usually the mundane missions, it's only the exciting or exceptionally interesting missions. As the various Enterprise's were both vessels pushing the frontier of known space and flagship vessels often given important tasks, these were more common than on other vessels.
In unusual or dire situations sending down the most experienced and well trained crew available is necessary, those crew are usually the officers.
As for sending down the captain, sometimes it's necessary, as in negotiations or anything formal or diplomatic, or the odd situation where the captain actually needs to be in direct command, usually it's more a case of noone being able to tell the captain no. | 25 | 35 |
How do I get productive while programming? | I have the ambition to program, but every time I open up my IDE, I just procrastinate for what seems like forever. Any suggestions? | Why do you open your IDE if you don't know what you're going to do?
Really the most effective approach here is to scratch an itch. But you need to have an itch first. It might be stupid small but that's enough to trick your brain into throwing an over-engineered solution at it. | 27 | 28 |
Could a bright enough light shine through metal? | So, light waves can be either absorbed or reflected by a material, or can go through a material. However, no material reflects or absorbs 100% perfectly. At least a few photons will go through (correct?).
Anyway, say I write a message on a white piece of paper, and cover it with a black piece of paper. I can't see the message anymore, but if I went in a dark room and shined a light under it I could.
If I did the same thing but covered the message with aluminum foil, it wouldn't work. What if I bought one of these expensive flashlights with thousands of lumens, would it work then?
Is there any amount of light that would make it possible to see through the aluminum foil? Or a different wavelength of light? Somehow "x-ray" it?
| Up to the plasmon frequency most metals will be an essentially perfect reflector/blocker of light given a reasonably thick cross section.
Beyond that frequency you get diffraction and scattering to lesser and lesser degrees as you increase in frequency.
In thinner sections there isn't enough material to fully cancel the electric field of the photon internally, resulting in nonzero transmission. | 22 | 27 |
Why do our eyes handle HDR situations fine (ex. looking own a hall at a bright window) but a camera needs a special mode? | Your eyes do several things that cameras don't.
1. Your eyes are constantly adjusting the effective "exposure" they're getting in real time. Your pupils are constantly expanding to let in more light and contracting to block it out, depending on what you're looking at moment to moment. Squinting in bright light can take this even further.
2. Your brain does a lot of postprocessing to create the illusion of a constant stream of vision, correcting brightness is only one part of this. Your brain edits out your nose, and the blindspots caused by your optic nerves. It corrects for color, brightness, and contrast. It covers up the blur that happens when you move your eyes or blink. It ignores the fact that only the central ~15 degrees of your vision is sharp and full color, and stitches together an approximation of the rest of your field of view from mental models and your blurry peripheral vision.
3. You actually have 2 different light sensing cell types, that have very different sensitivities, and you automatically switch which ones are dominant. Cones are responsible for full color, sharp, detailed vision, but need a lot of light (relatively) to work. Rods only sense light vs dark, and don't form as sharp of an image, but work with extremely small amounts of light (starlight with no moon for example) and are very good at detecting movement. This is why you can navigate at night, but you can't read: your rods let you see objects, but not details as small as most text. | 62 | 34 |
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Are there any other species that use tools to "improve" their environment? | Adam Savage pointed out that humanity's ability to adapt to our environment (and adapt our environment to ourselves)^1 has been a major evolutionary advantage. Clothing seems like the earliest example of this kind of adaptation. Unlike tool use for hunting/gathering, which definitely predated homo sapiens and shows up in other species, is use of tools for creating habitats unique to us?
1) https://www.youtube.com/watch?v=vjOOD70T_fM#t=13m39s | Beavers essentially create habitat for themselves by building dams, and creating ponds. Those ponds provide a relatively safe watery environment to inhabit and build their lodges.
That said, beavers kind of do one thing really well, and they don't have the power to invent new tools and concepts like we do. No chance of a high tech beaver empire for now.
Still, they totally fit your question of using tools (dams, sticks, mud) to create habitats imo. | 37 | 15 |
What is the relationship of quantum field theory to quantum mechanics? | The way I see QM is as a sort of general "protocol" for making predictions at the quantum scale. First, choose a Hilbert space representing all the possible states of your system; then choose a self-adjoint operator A representing the variable you want to measure; find the eigenvalues and eigenvectors of A; use the Born rule to calculate the probability distribution; exponentiate iA to find the time evolution.
My understanding of QFT is that it uses this protocol to model fields like the EM field, so that the basic procedure is the same; the difference is that you use classical fields as a guide for choosing Hilbert spaces and operators, and this leads to things like Feynman diagrams and whatnot. How correct is this? | Correct. QM is a framework in which to describe physical systems. QFT is basically a certain subset of QM where you
1. Can create and destroy particles, and
2. Treat things relativistically (as in *special* relativity).
To make a classical theory quantum, you just apply the postulates of QM. You describe your system as a state vector in a Hilbert space, you promote dynamical quantities to operators, and "have at it".
To turn a classical theory into a QFT following canonical quantization, you promote your fields to operators which create and destroy particles, and impose the canonical commutation relations.
To get from there to Feynman diagrams, you just consider time evolution and expand the time evolution operator (or the S-matrix for scattering problems) in a perturbation series. There are some cool tricks due to Feynman, which allows you to do everything in a relativistically invariant way, and Wick, which allows you to easily work out the kinds of diagrams you need to draw. | 19 | 46 |
[Matrix] Why do the agents miss their shots? | Any hacker worth their salt can make an aimbot.
What up?
Is it all a ploy to get Neo to the architect? | Agents can bend the rules but not break them. Pistols aren’t terribly accurate at range and hitting a moving target is hard. Or rather it’s hard to hold a pistol accurately. If they’re held in a clamp they’re accurate up to hundreds of yards.
Copied from somewhere else, I’m no expert:
The Model 1911 .45 semi-auto, in its unmodified form, was rated by the Army as having an effective range of 50 yards. The Army definition of effective range was the range at which a soldier of average skill, trained with the weapon, could hit an enemy soldier anywhere on his body, with half his shots, if the enemy soldier were standing still in the open. | 19 | 16 |
Is Deleuze a post-structuralist, if so, how does his concept of difference differ from the structuralist concept of difference? | Oh boy this is a hard one, because Deleuze's relationship to structuralism is not stable through the course of his works, and even where - as with 'early Deleuze' - his takeaways from structuralism are unambiguously positive, they are always filtered through a Deleuzian vocabulary that makes his structuralism incredibly idiosyncratic. So, for instance, there's an early essay of Deleuze's, "How Do We Recognize Structuralism?", where he lays out six 'criteria' by which we can 'recognize structuralism'. What's fascinating about it is that if you read it along with his major works published soon after (*Difference and Repetition* and the *Logic of Sense*), that essay contains, in embryo, almost the entirety of what would become those works. In other words, if those 'criteria' are 'how we recognize structuralism', then we cannot help but 'recognize' Deleuze's early solo works as not only meeting those criteria, but elaborating and expanding upon them, in new and creative ways.
What's tough about it is that even while Deleuze self-identifies some of his major concepts as structuralist in this period, it's kinda hard to recognize them *as* structuralist from any 'orthodox structuralist' perspective. So for example, when Deleuze identifies one of his most important concepts from that period ('the virtual') as being nothing other than structure itself ("the reality of the virtual is structure" *DR*209), and then when he further goes on to identify the virtual with what he calls 'the problematic' and the 'Idea' (which have their own provenance in Plato, Kant, and Maimon), this chain of identifications is almost entirely original to Deleuze, even as it can be said to 'translate' the notion of 'structure' in a way more or less consistent with structuralism proper. So one might cautiously say that Deleuze is transcribing sturcturalist ideas into a 'non-strucutralist' vocabulary. Does this make him a 'post-structuralist'? Or is he rather elaborating and expanding the richness of structuralist concepts? Hard to say.
In his later works, Deleuze becomes positively hostile to, at the very least, the nomenclature of structure. In fact, a great deal of his conceptual vocabulary in the later period is defined by being engineered *explicitly* to be counterposed against any notion of structure: in *Anti-Oedipus*, 'Oedipus' is pretty much another name for structure ("Oedipus-as-structure" *AO*107), which means the book may as well be called 'Anti-Structuralism'. Elsewhere, 'machines', 'the rhizome', 'schizoanalysis' and 'the event' are all deliberately theorized as being alternative ways of thinking about things than in terms of structure (to quote the Deleuze scholar Daniel Smith, who himself is quoting Deleuze's biographer, Francois Dosse: "‘Machine’ is a veritable catchphrase that was meant to dethrone another catchphrase of the time: the notion of ‘structure.'" In contrast to the idea of "structure," which seems to suggest something fixed or static, activity seems to be built into the very notion of a 'machine'". Smith, "What Is the Body Without Organs?").
Bringing the question of 'difference' into it makes the problem yet more complicated. One way to think about what early Deleuze is doing with structuralism is as 'purifying' the notion of structure so as to expel any trace of either 'identity' or 'the negative' associated with the concept ("the difference between differences relate difference to itself without any other intermediary"). This in contrast to 'the structuralists' proper who are a little ambiguous about this. It's possible that, in Deleuze's later work (where the 'virtual' and 'the Idea' also recede in importance, if not disappear entirely), 'structure' itself become a constraint on thinking about difference that had to be sloughed off. Especially if one takes Deleuze at his word when he (and Guattari) simply identity Oedipus with structure (in which case *Anti-Oedipus* more or less details point by point why structure is no good). And even then, in a 'late' work like *A Thousand Plateaus -* written after *AO* \- perhaps the most important conceptual distinction that runs through the entire book (one of the few distinctions that remains stable throughout that sprawling, disjointed work - that between 'content' and 'expression') is drawn from noneother than the structural linguist, Louis Hjelmslev.
So is Deleuze post-structuralist? Er, it's complicated. | 36 | 21 |
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Does burning cash (literally, with fire to ashes) improves the strength of a currency? | If yes, then by how much?
is there a paper that deal with this scenario? | If by strength you mean its value to others. Well if you are creating too much that it is inflationary then destroying some to make it less inflationary could improve its value relative to others.
However the utility of money which is to act as a medium of exchange could be reduced if you do not have enough money for commerce. | 44 | 70 |
ELI5: Why do counties have different names in different languages? | Example: Deutschland is Germany in English. Why dosnt everyone just call a country by the name it gives itself? | Translation into other languages, including mispronunciation and physical inability to pronounce certain sounds.
1) Translation: countries like the United States are just words. You can directly translate them into a different language. In Spanish, it's Estados Unidos. The words just happen to have pretty direct translations.
2) Mispronunciation: Turkey in Turkish is pronounced probably closer to the spelling Turkia. It's not that hard for an English speaker to try saying. But they didn't. Keep in mind, too, that country names can be very old. So at some point, the mispronunciation is simply the way you say it in that language.
3) Inability to pronounce certain sounds: language is interesting. We're born being *able* to learn and produce all phonetic sounds of any language. But at a very young age, you lose your ability to say sounds that aren't familiar.
In English, R and L are very different. In Japanese, they're very similar. You actually lose the ability to even *hear* the difference if you aren't exposed to it as a child. In Hindi, there are 3 different ways to pronounce the letter D. It's really hard as an English speaker to even tell any difference between them. And this is proven by experiment: if you slowly transition an R to an L step by step with computer programs, English speakers have a clearer threshold where R becomes L. Japanese speakers have a lot harder time having a consistent threshold of detecting which is which. Same thing for English speakers and the D's. | 46 | 49 |
What do PhD graduates who get jobs in industry do differently in their PhD program than their peers who get academic jobs? | Options post-graduation basically boil down to academia and industry. I personally would like to go into industry. So what traits, experiences, etc do students tend to display during their PhD program that allows them to jump into industry afterwards? Was previous industry experience a factor or had they gone straight from BS to PhD? | Joining a research group that has placed people into industry. Usually the first position for a newly minted graduate is due to getting one's CV in the hiring manager's hand from someone inside of the company. I've seen this time and time again. Otherwise, you're battling extremely poor signal-to-noise ratios. | 24 | 35 |
Was scientific racism actually "bad science" by the methodological standards of the time? | Apologies if this has been asked before but I have searched around and been unable to find any good discussion on this point.
Obviously the racial science conducted in the 18th, 19th and early 20th centuries purporting to classify various races into scientific categories and measure them by their intelligence, brain size, savagery, etc was tremendously flawed and harmful. Today we know that our folk racial categories are very weak socially constructed proxies for complicated genetic patterns, that 'savage' and 'civilized' are not objective scientific terms, that geographic and ecological factors are mostly responsible for the technological, social and epidemiological advances which the West made over other countries, that those advances were smaller than the West realized at the time, that phrenology and craniometry do not provide any useful information, and so on. So a lot of people regard what was done in the old days as pseudoscientific.
But lots of other scientific inquiry conducted in other fields in those times was later discredited.
Obviously their conclusions were wrong, but to what extent can we actually say that their methodology was pseudoscientific by the standards of the time and rooted in racism? In other words, how do we know that they only came to the conclusions that they did because they were motivated by a desire to show that their race/country/religion was morally superior, as opposed to simply doing what made sense to them? They didn't know what we did now, and the empirical evidence available to them was that there were relatively distinct different races which had different technological and social capabilities. Is it likely that an unbiased inquirer, to the extent that we can hypothesize such a person in that historical context, would have come to similar conclusions?
Obviously I'm talking about work which was conducted in many different countries for more than a century and a half in various fields of natural and social science. So probably a generalization is not possible. But any information on this would be appreciated. | I would recommend you check out *The Mismeasure of Man* by Stephen Jay Gould. He wrote about this topic extensively. In his book, he analyzes the work of Samuel George Morton, a renowned race scientist of the 19th century who had the largest collection of human skulls in the United States and was dedicated to using craniometry and supposedly "objective" anthropometric methods to determine the limitations and qualities of each racial group. During his time, Morton was revered as an exemplary empiricist, relying only on the "evidence" of racial differences in the skeletal structures of human beings. Gould's fundamental conclusion, however, showed that even though Morton used quantitative methods, both his measurements and conclusions were biased by his racial-ideological conditioning. Though Morton measured skeletal structures, found the volume of different races' skulls, and generally took obscure measurements, Morton and his ilk failed to see the fallacies their work was based upon, however, because their social context limited their vision his set of unquestioned assumptions about what was true inevitably impacted his scientific conclusions despite the seemingly objective nature of his quantitative methods.
Gould reveals the race scientists' biases by reevalutating their measurements. Gould goes over the multitude of methodological failures of Morton. Firstly and most critically, Morton assumed that intelligence could be quantified. Since Morton believed it related to the physical size of the brain, measurements of the skull were interpreted as objective measurements of intelligence. However, there is *absolutely no proof that this is the case.* One's skull size holds no bearing upon one's abilities or potential. Morton, because of his historic notions of racial hierarchy tracing back to Aristole's Great Chain of Being, Carolus Linnaeus racist categorizing of people, and his upbringing in the slavery capitalism of the US, was unable to realize this fact. In beginning the process of measuring his subjects, Morton massaged his sampling to match his preconceptions. He unconsciously selected for whites with large skulls, but overrepresented Inca Peruvians with smaller ones. When measuring whites, Morton tended to sample male skulls, but mainly measured black female skulls. His results apparently showed a large gap between the skull sizes of whites and blacks. However, when analyzing these differences, Morton did not note that men simply have larger skulls than women. He inflated the racial differences in skull sizes in order to epistemilogically solidify American racial hierarchy Furthermore, Morton's measurements themself reveal a bias towards whites. Morton remeasured the volumes of the skulls in his collection with both pieces of lead and seeds. In the process of remeasuring, however, large discrepancies arose between his original seed measures and the newer volume readings he got using pieces of lead to take skull volume readings. It turned out that white skulls had heavily benefited from being measured with seeds as opposed to lead, coming out with far higher volumes than black, Indian, or Asian skulls. With seeds, skulls could potentially be shaken to settle them within the skull, or stuffed inside of the skull when measuring volumes. Morton could not do this with his lead measurements. However, whites always had consistently larger volumes over other races when measured with seed--a discrepancy that was largely erased when using lead. Gould suggests that this discrepancy could have originated in Morton's assumption that whites would simply have larger skulls than others, and naturally stuffed more seeds into those skulls, but would never have bothered with a black skull.
Gould argues that even though Morton used quantitative methods, and was in fact the standard of his time when it came to the quality of scientific endeavor, his work was nonetheless impacted by the social context of imperial racism that shaped his conclusions *and* even the measurements themselves. Most importantly, what Gould demonstrates is that even if scientists attempts objectivity using seemingly neutral methods of quantitative inquiry, scientists are always impacted by their settings. So to answer your question "was it bad science?" well, Morton's work was highly popular and widely accepted in academia when he was writing because he used the tools of objectivity to approve the dominant power structure of his time. But just because he used those tools does not mean that he was doing "good science, because his reliance upon numbers and measurements did not guarantee any actual truth value in his work. Rather, he validated the social structure he grew up in. | 70 | 88 |
CMV: Government spending should be referred to as money spent per person living in the country, not the absolute amount. | Lets take the latest US infrastructure bill as an example: 1 trillion dollars spent. That is an amount I can't really grasp. However if you were to divide it by the US population (330 million) it would come out to be $3030 spent per person living in the country. That's an amount I can actually relate to.
This could also be done state level i.e. state spending divided by state population.
Of course the amount wouldn't be exactly what you pay for it (in taxes) as thats obviously dependent on your income etc. but as a ballpark estimate it would still be way more relatable than the absolute amount.
Another reason against it would be that the US also taxes citizens living abroad which are therefore also paying for the spending but they won't be included when dividing by the population. However that would still be a small amount. And also this is specific to the US as other countries generally don't do that. | The idea seems good on its own, but how would you mandate it? News agencies often change the way they present numbers depending on whether they want to make it seem big or not, wouldn't they also choose whether to use this method or not based on what they want to make you think? | 232 | 1,522 |
What happens during near-death experiences? | First off: there isn't all that much known about NDE's apart from anecdotal experience.
Chemically, it is often said that during an NDE, there is a release of certain neurotransmitters in your brain, including the powerful psychedelic compound DMT. This is often used as the explanation of the NDE, and the effects of DMT do often correlate with those reported to happen during NDE's.
The 'typical' experience often involves floating above your body and looking at yourself from above; possibly flying around and visiting relatives etc. If you want to experience similar things, try lucid dreaming, meditation and even DMT itself. | 31 | 88 |
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ELI5: Why do employers want experience for entry-level jobs? | We've all heard of employers who demand a couple of years' experience for even entry-level positions, but I still don't understand why they do that. What's the logic behind wanting that much experience for an entry-level job? | proof that you can function in a work environment.
seriously... look around you, sad fact is that a sizable portion of our society cannot be relied upon to even show up consistently. Let alone perform semi complex tasks of some importance.
Truth is, they will always *want* experience, doesnt mean they require it. But if they can get enough applications with experience, why wouldnt they. there are internships and tertiary job fields that can provide the first foot hold. | 42 | 22 |
ELI5: How was it possible to build those highly accurate CNC machines we have today? | As the questions in the title says, how could we build those higly accurate CNC machines (or any other manufacturing machine) to that accuracy, assuming you need accurate machines to machine the accurate parts for the accurate machine?
Was it some kind of „make 10 parts, take the best one“ and repeating this and gaining the accuracy through that?
And to take the best part, you need good measuring tools and they needed manufacturing by accurate machines and so on.
Its like „what was first, the egg or the hen?“ | One of the most important parts of how very high precision machine tools are made is the fact that clever design allows relatively inprecise parts to be assembled into a machine that can make a more accurate part. A pretty good example of this is the micrometer, which uses a screw to measure parts with a significant level of precision. Screws are easy to make on even a relatively crude lathe, and micrometers can be used to check the accuracy of parts that will be made into a more precise machine. Another important part of making good machine tools is being able to make perfectly flat surfaces that can be used as beds, machine ways and reference planes. In theory it's possible to rub or scrape any three non-flat surfaces together in a specific order and eventually they will reach whatever level of flatness that is needed for their intended application, without any fancy tools or precision equipment required. | 18 | 19 |
What do software architects use to plan in advance? (UML tools?) | I'm a self taught Python dude (Biotech pivoting to bioinformatics) and I've been learning through building a procedurally generated video game. As the game gets larger, progress gets slower. I spend (imo) too much time drawing out class architecture and the flow of data, only to have things change the next time I add a feature. There's got to be (free) tools out there to make this easier, but I really don't know what those would be. My googling usually leads me to "3d modeling tools" or "software tools for architects/civil engineers". Even looking at the "best UML tools 2020" I don't know if that's actually what I want, or what the difference between a good and bad one is. I feel like I'm suffering from "I don't know what I don't know" syndrome since I've never taken actual classes or had a mentor. Any help is appreciated. | I've been a professional software engineer for 12 years now.
I would say that it's not super common to use UML class diagrams in big software companies. As you note, these things change frequently. It's just a fact of life - you can rarely plan the entire system from the beginning. Often you don't even know what you really want until you build it. For your example with a procedurally generated game, maybe you start with just a collection of objects in the world. But then you realize that's too slow, so you need some tiling system to generate new tiles as the player nears them. Then you need a way to unload old tiles (and maybe save enough state to regenerate them the same later).
Experience will help you get better at planning ahead for these things, but there will always be surprises.
In general, such diagrams are most useful to communicate designs between different members of a development team. Usually the class structure shouldn't be super complex, so it can be documented in comments or design documents (usually explaining what the code is trying to accomplish and why is the more important task).
I will say that state machine diagrams or sequence drawings can be pretty helpful. For state diagrams, it can be really helpful to list and explain all of the possible states and show what the transitions are. For example, in a multiplayer game, you might have states for players waiting to join a game, in active gameplay, waiting for respawn, etc. This is particularly useful since many different systems might need to deal with the state. | 17 | 30 |
Is learning RStudio better than MATLAB? | Currently an undergraduate student studying Genetics. I'm learning data computing in RStudios at the moment but I was wondering if other programs like Matlab are better or more helpful when I apply for Master's/PhDs? | Not a genetics student, but it's always valuable to learn a well supported open source language like R or Python.
MatLab costs a small fortune for a licence, and while in academia it shouldn't be an issue just generally there may be a time where it's not always available because of this reason. | 112 | 84 |
ELI5: Why is it hard for me to watch others embarrassing moments i.e. Embarrassing scenes in movies and such | It is because of empathy, of the ability to put oneself in another's shoes. Most humans have an innate sense of empathy, but the degree varies depending on how much a person develops the thinking habits. By default, though, many humans will not like seeing embarrassing things due to empathetic embarrassment. | 21 | 18 |
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Is there a chemical way to supress sexual feelings? | Wasn't sure if this was a better question for askreddit, but i'd like some more intelligent suggestions based off psychological knowledge or chemical/hormonal expertise. Have there been any drug studies of the sort? | Yes, several medications have been investigated for this purpose, and some are used. Certain anti-depressants were found to have a common side effect of diminished sexual arousal/desire and are used for treatment of things like premature ejaculation. Androgen antagonists are also used to treat more significant hypersexual disorders, especially in cases of criminal sexual deviance. | 12 | 15 |
ELI5: Why is it easier to gain back muscle after a period of not working out versus when you first started going to the gym? | The title. | There are two mechanisms for muscle growth. Hypertrophy and hyperplasia. The former refers to protein accretion, so think of it as muscle cells gaining mass. The latter refers to a form of proliferation, where you either get more muscle cells or the cells get more nuclei. Both lead to an increase in size, but when the muscle atrophies (loses size) due to lack of use or mechanical stress, size is lost because of a reduction in size of individual cells due to loss of protein content (and others), but number of cells and number of nuclei is more resistant and stays longer.
So when you lose muscle mass and want to regain it, it is easier to do when you already have more cells and more nuclei per cell. However, hyperplasia capacity decreases over age. Because satellite cells (muscle stem cells) decrease as you age. So if you gain muscle size at a young age, lose it, and train again, it's easier to regain the size than if you started training at an older age, lost it and tried to regain it again. | 46 | 29 |
CMV: Satan is the hero of the Bible. | I’m speaking purely in a literary sense interpreting the Bible as a narrative. I’m not religious I’m not a Christian or satanist. To me this is like discussing whether Hector or Achilles is the protagonist of the Iliad. This is not a novel idea. Paradise Lost essentially frames Satan as the protagonist but I think if you look at the stories of the Bible typically attributed to Satan (for example the serpent is not specifically mentioned to be Satan but has been interpreted that way culturally) Satan is the good guy of the Bible.
Genesis: Satan convinces the humans to eat of the tree of good and evil. This is framed as a bad thing because human beings now die and experience suffering. But I would argue this is a massive gift from Satan. Knowledge of good and evil gave us ethics and free will. We now could make choices which gives our lives meaning. And again without death it’s impossible for our lives to have any meaning. If we lived forever we’d do everything we could possibly do 100,000 times and we’d still have an eternity left. Death gives our lives purpose and meaning. It means what we do matters I consider that a great gift. Now every hero needs a villain and that villain is obviously god. The guy who made a bunch of creatures to worship him like an authoritarian psychopath and when one guy wanted independence he threw him into an eternal torture chamber. Real heroic stuff. Then after making people, tempting them with the fruit despite the fact that he chose to not give them a sense of right and wrong, he then decided to drown them all because the creature he designed was “wicked”. Then he kills a bunch more people for being gay, then he orders a few genocides in Joshua judges kings etc. our buddy Satan doesn’t show up again until
Job:
Not satans best look, but God sure looks like a douche here. God bets Satan that Job will praise him no matter what Satan disagrees, so God let’s Satan ruin jobs life. Eventually Job gets angry at god, the all knowing god somehow loses a bet then he goes to yell at job and basically tells him “your suffering is for reasons beyond your understanding” when in reality the reason was god wanted to win a bet which is a terrible reason
Finally we have the New Testament. Where god decides the only way he can ever forgive the creatures he made, is to sacrifice a perfectly innocent person in a brutal method of torture. That’s the only way his insatiable blood lust can be partially taken care of. But only for people who believe it on really weak evidence. God still needs some people roasting in hell to fill his nostrils. He couldn’t just go on a loudspeaker and tell the world hey I’m sending a sacrifice to die for you because I love you and want to be with you. You have to believe it because it’s in a book. But anyway Satan offers to give the perfect being Jesus all the power in the world. Imagine a world run by Jesus the most perfect loving human in existence. What kind of global government could he have made with Satan’s power helping him. He could’ve prevented the holocaust, Ghengis Khan etc. but instead nope this perfect beautiful human being needs to be slaughtered and tortured because God just hates his own creations so much he needs to see a perfect person tortured to be satisfied. So Satan tried to save an innocent person and institute a one world government led by gods incarnation on Earth. Sounds pretty heroic to me
Revelation:
God is preparing for his final solution of condemning the vast majority of humanity and creation to eternal torment in the lake of fire and establishing his thousand year theocratic dictatorship a thousand year reich you could say where His sycophantic Christians rule over all the rest of humanity as second class citizens. But then Satan has one last heroic attempt at rebellion. Even though he knows he’s doomed to fail. Even though he knows the cards are stacked against him he rebels anyway because he knows it’s better to die fighting than to die a slave. A tragic ending to a tragic hero | First, the Bible is a collection of disparate texts written by different authors in different centuries in different cultural contexts. Attempting to read it as if it is a unified whole is basically a theological viewpoint ("God-breathed scripture").
With that in mind, note that there isn't really a 'Satan' in the Tanakh. In Job, you have the 'ha-satan', or the accuser, and a similar figure appears in Zechariah. That's it. The idea of Satan developed in the Second Temple period as the ruler of evil, taking influence from Zoroastrianism and other pagan philosophies. In apocalyptic thought, which is where Christianity eventually developed from, Satan was the cause of evil in this world, and his eventual defeat would usher in the 'kingdom of God' where evil and death would be driven out.
All this is to say that he's not the protagonist because 1) there isn't a 'protagonist' of the Bible and 2) in the Christian conception he's very clearly the epitome and cause of evil. | 41 | 29 |
ELI5: What determines whether gas comes out your mouth or your butt? | It depends on where the air is released or generated in the metabolic process. If you drink a carbonated beverage, there's a lot of gas dissolved in the soda so you're more likely to burp it out. Other foods create gas as a metabolic by-product and that usually stays trapped in the digestive tract to produce flatulence. If gas is produced in the stomach, you are likely to belch it and if it is produced in the intestines, you would fart it. | 17 | 19 |
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ELI5: Why do we borrow money from China and give it to countries like Pakistan | How exactly is the juice worth the squeeze? | We don't do anything similar to that.
What you're referring to is bond sales and foreign aid, two topics that are merely tangential to each other.
Foreign aid is a topic in diplomacy and international relations. It's got both moral and pragmatic dimensions to it. On the one hand, the moral argument goes that those who have more should do more. It's pretty simple, and no different really from the basic moral arguments for charity or generosity … or even hospitality, when you get right down to it. The pragmatic argument is that foreign aid prevents conflicts.
Deficit spending is a *completely* different kettle of fish. It basically works like this: There are two ways, generally speaking, in which governments can fund their activities. One is taxation, and the other is the sale of bonds. All extant governments (worth talking about, anyway) use both of these methods in combination. Taxation is just what you think it is: taking money from the populace through the authority of law. But there are obvious downsides to that approach, both philosophical and economic. So taxation only gets you so far.
Bonds, however, are clear-cut. When a government wants to spend some money — whether it be on buying an aircraft carrier or paying the salaries of a police force or building a school to replace a madrassa in, yes, Pakistan — it issues a series of bonds and sells them on the open market. Anybody can buy bonds. In the United States, about half of all the outstanding Treasury bonds — nearly $8 trillion worth — are held by the government itself, one agency buying bonds from another in order to move money from bank account to bank account. So those really don't count, in any meaningful sense.
Of the rest of the bonds, the largest share — about $4 trillion — is held by *us,* the American people, in one form or another. Over $1 trillion of that is held by individual US citizens who have bought and own US Treasury bonds as personal investments. The rest is held by domestic institutions, like mutual funds, pension funds, insurance companies, state and municipal governments, commercial banks, credit unions and so on.
And the other quarter? That's held by those same kinds of holders — institutions, private citizens and governments, and most prominently central banks — in other countries.
So what about China's share? China's central bank holds about a quarter of the foreign-held US Treasury bonds — the largest share held by any one party, but just 8% of the total sovereign debt.
And *why* does China's central bank hold US Treasury bonds at all? Because US Treasury bonds are more valuable than yuan. The Chinese central bank can do a better job of managing China's economy if it converts as much of its cash reserves into negotiable instruments of stable value, and US Treasury bonds are the most stable negotiable instruments on the planet. If the US didn't sell Treasury bonds, China's central bank — as well as the central banks of Japan, Brazil, the UK, Switzerland, Taiwan, Russia and all the other economies that currently use the dollar as their preferred reserve currency — would just go shopping for the next best investment and put their money into that instead.
So long story short? The US sells Treasury bonds — "borrows money," if you like, though that's a really misleading way of looking at it, since it implies we're talking about personal debt — because there's a *huge* demand for them, and the revenue from bond sales lets the US do more each year than it could do if it relied on tax revenue alone. Since the American people generally agree — at least right now — that their government should be doing more rather than less, the sale of bonds is a very lucrative way of funding all those extra activities that we couldn't do if we just spent tax dollars.
And yes, one of those *myriad* extra activities is building schools to replace madrassas in Pakistan. | 17 | 16 |
ELI5: Why does our body sometimes moves or shakes when We remember a cringy situation from the past? | If the situation triggers a flight or flight response, the body's first impulse is movement.
A loud noise behind them will cause most people to start. This is your brain telling your body to fire up its muscles and get ready for whatever is about to happen.
Remembering a sufficiently unpleasant situation could trigger a similar flight or fight response, firing off muscles for the hardcoded classic danger response that nearly all mammals share. | 24 | 72 |
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[Anything really] Examples of druids that aren't named as druids? | Ancient Druids were the educated elite of the Celtic people, like doctors and poets, and were responsible for the religious aspect of Celtic society.
The more common interpretation of the druid is generally of someone who communes and lives in harmony with nature, often gaining magical abilities in the process, such as spells and the ability to shapeshift into various animal forms. They might worship nature itself directly, or a nature god/goddess, or they might simply strive to keep the 'balance' of the world between civilisation and the wilderness.
Radaghast the Brown from Middle Earth, while technically a wizard, is very similar to many of the more popular interpretations of what druids were like. He lives in the wild and is a little odd from being alone so long, can communicate with animals, etc. He just lacks the shapeshifting.
Malfurion Stormrage from Warcraft is another one, and he can shapeshift as well as use a whole host of other magical powers.
An argument could be made for Merlin being a druid in certain interpretations, though he's more commonly viewed as a wizard.
There are a bunch of D&D characters that are druids. First one to come to mind is Pikel Bouldershoulder, who's a *dwarf* druid. | 24 | 15 |
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Does fiber simply speed up our digestive system, or do our bodies want to expel fiber quickly? | Fiber acts as a bulking agent, and as mentioned by HonorAmongSteves, it carries water, creating a rather substantial mass that moves through one's digestive tract. Peristaltic movements by the colon and eventually defecation are stimulated by stretch receptors present in the wall of the colon. Due to the increased bulk in the colon, stretch receptors are activated, passage is expedited, leading to a faster mouth to anus transit. | 18 | 19 |
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Is it better to teach theories first before empirical research? | Hi everyone, I am new to teaching and currently working on a module on the sociology of education, which requires students to describe, apply and evaluate both theory and empirical research. I’m in a little bit of dilemma on how best to structure the content. I usually start by presenting data around a given topic before bringing in relevant theories to make sense of the data. However, I am wondering whether it is is better to first introduce perspectives and then consider research that both supports and challenges those perspectives? Any insight would be greatly appreciated. | Not your field, but I've had success with an illustrative case followed how different theories explain the case. Then more on the empirics. Case helps make the topic 'real' before revving analytic thinking with theories and using theories to understand the data. | 10 | 15 |
CMV: The gender pay gap is largely explained by factors other than gender. | When I first started hearing about the general consensus that women are underpaid compared to their male counterparts, (sometime around 2015) I was quick to believe that it was a result of deeply-rooted, institutional biases by employers and business models.
Since then, on several occasions, I have deep-dived, to try and find my own sources of information and get a clearer picture of what exactly was happening and why.
Unfortunately, the more I read, the more I find that
A- The wage gap is nowhere near as large as the general twitter-sphere claims it is (as much as 18%) and in reality it appears to be closer to 2%.
B- Most of the reasons for this gap are explained by factors OTHER than gender, such as education, experience and industry.
So, I have arrived at the conclusion that essentially, people are making a mountain out of a molehill and any attempt I make to point out that the pay-gap is not as widespread and gigantic as social-media clickbait would lead you to believe, I am made to feel like an ignorant misogynist.
I really do want to have my view changed on this. I'm generally very progressive, and I want to be presented with information that will unlearn this viewpoint I have.
I find myself at odds with my girlfriend over it and I can't bring myself to just lie and say "You're right, women are overpaid everywhere because sexism, the end".
Help me out, Reddit. | It depends on what you mean by including gender as a factor here.
On average, the main drivers of the "wage gap" are:
* Women on average tend to favor flexible hours over money. More women work part time than men. This is likely because women are still expected to do unpaid house and care work for their family should the need arise.
* Women tend to only apply to jobs they are fully qualified for. Men will apply to jobs that they are underqualified for.
* Women tend to be less bold in salary negotiations.
* Women tend to make different subfield choices than men, usually preferring more "people-centric" lines of work. For example, a roughly equal number of men and women graduate medical school, but more women tend to go into pediatrics afterwards, while more men go into anesthesiology. The latter pays more, so men in medicine will tend make more (because of all the aggregate subfield decisions in this direction.)
Now the question is: are women making these choices because they reflect their authentic desires, or because they feel pressured to? If you think that the difference in choice is primarily driven by how women are socialized, then there is still an issue here that could be resolved. It just pushes advocacy back a step to advocacy for cultural and norm changes. We could normalize women not taking time off to take care of their families, being workaholics who work 50 hours a week, etc.
On the other hand, if you think that women and men have naturally different psychological tendencies on average, then you might say the world is close to being just, even if we have different outcomes. | 126 | 164 |
ELI5: What is the difference between theory and law in science? | For example: theory of relativity and law of gravity.
I googled this but answer wasn’t clear to me. | In science a law is a **description** of an observed phenomenon. Often this takes the form of a mathematical equation describing the relationship between observed phenomenon.
A theory in contrast is an **explanation** of why a phenomenon exists or what causes it. They run the range of completely untested guesses to enormously supported explanations accepted by basically everyone as correct; there is no "graduation" from one thing to another via consensus or evidential support, a theory is always a theory no matter how well or little it is accepted. | 44 | 18 |
Do philosophers have a moral obligation to follow their own school of thought? If not, is there a rationale for not doing so? AKA why aren't all philosophers vegan? | This question primarily stemmed from my pondering on whether there was any argument to be made to support the eating of meat. I have search through both /r/askphilosophy and /r/philosophy and the consensus seems to be that no, there is almost no philosophical justification for eating meat if there's no nutritional need to do so (which for most adults there doesn't seem to be).
But I also got the indication that while most philosophers (assuming at least some fraction of people posting in these subs have a background in it) agree that eating meat is not morally acceptable, they still do so themselves. That raises a more fundamental question? Do philosophers today follow whatever school of moral rules they believe makes most sense to the extent that it does apply directly to their life? Did philosophers of the past do so at least? And if a philosopher chooses not to "drink his own Kool aid" in the parlance of our times, is there a moral justification they can give for not doing so? | Interestingly, ethicists *are* more likely to be vegan than laymen, in addition to being more likely to hold the ethical position for which veganism is one consequence.
Nonetheless, even among the philosophers who agree with the ethical position, a majority are not vegan.
To me, this really seems like a question about human psychology and how people rationalize/how our beliefs do or do not motivate our actions. | 28 | 22 |
[ELI5] With supply-chain delays of trucks, ships, etc. costing "millions of dollars per day," who exactly is it costing? | I'm reading about the backup of trucks at the border between Mexico and Texas, which was said to be costing $100 million a day (when trucks were stopped), and now $2.4 million per day with the inspections. But none of the articles explain how the economics of this work out.
While I understand it has an economic impact, I'm a little unclear on who it is "costing". Is it the trucking companies, because they have to pay drivers for more time? Or the companies who sold the goods? The ones buying them? (Or all three?)
Like, if a truckload of apples rots while sitting at a checkpoint, who pays for that? I would assume the trucking companies have insurance. Or are the buyers having to pay for rotten apples? Or do the sellers have to eat the cost of lost product?
I know costs could eventually hit consumers due to shortage of supply, but that seems like a different issue. | Many businesses rely on estimates of what they expect to receive and sell, not having the product to sell while still having costs to pay (like payroll) means they count each day of lost sales as direct monetary loss | 55 | 62 |
ELI5: If a fever, coughing, vomiting or diarrhea are the body’s defenses fighting an infection, why do OTC drugs offer to combat the symptoms? Wouldn't you want the body to do its job? | I understand that deaths related to Spanish Fever were caused by the body's overreaction, but most symptoms of a sickness are the body’s defenses fighting the battle. Shouldn't they be aided and not suppressed or is it all just marketing and they are really just drugging you with a small dose of DXM? | The symptoms you list might be *part* of an immune response, but the real work in fighting the infection is being done at the cellular level by your immune system. Stopping these symptoms does not stop the immune response.
If you have a cold and you stop the runny nose by taking something, the immune system hasn't shut down. It is still actively fighting the virus. But you just aren't as miserable.
In more extreme cases, like high fevers where the fever does actively help the body, the issue is that the body can push the fever past the point of helpfulness and into a dangerous realm. We don't know why it does this. We do know that you can suffer long term consequences from running a very high fever for an extended period of time, so the fever gets treated alongside the illness.
Some symptoms, like vomiting or diarrhea, might help flush out the issue, but again, can cause harm to the body as well (dehydration being the main one here). They are also not fun symptoms to experience. But even though these are part of the immune response, they are not the whole thing. The real work is being done at the cellular level. | 37 | 41 |
How has the understanding of exoplanets changed since the first were detected in 1988? | Among various discoveries:
* Exoplanets seem to be very common for many types of stars - other than failing to detect planets due to technological limitations, just about everywhere we've looked for planets, we've found them. We've even observed what are believed to be the remains of destroyed planets around white dwarfs, the dead remnants of stars.
* Planets can exist both much closer and much further from their stars than we see in the Solar System. The discovery of "hot Jupiters" (and then hot Saturns, hot Neptunes, hot Super-Earths...) came as quite a surprise, and their formation mechanism is still an open question.
* Planets come in all shapes and sizes. Whilst there is quite a gap in size between Earth and Neptune in the Solar System, we've found plenty of planets with intermediate masses and radii. There is still debate as to whether these are Super-Earths, Mini-Neptunes, or an entirely different type of planet.
* Exoplanet atmospheres are also diverse. We've seen clear atmospheres, hazy atmospheres, thick cloud decks, no atmospheres, atmospheres visibly being boiled off by a star - again, attempting to describe these variations and work out what types of clouds exist are hot topics in research.
* Multi-planet systems are common, especially for rocky planets. Once again, a feature that is unlike the solar system is how close some of the known planets are to one another - theoretical work implies that they are about as close as they can be without disastrously affecting each other's orbits. | 24 | 17 |
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Why we are more flexible when we’re younger? What changes as we age so it’s harder for us to stretch? | NAD or licensed professional but am a exercise science major + working under a physical therapist + occupational therapist.
Our bodies lose a small amount of flexibility as we age due to natural aging processes. This can occur due to a variety of factors such as a loss of water in our tissues and spine, increased stiffness in our joints, and a loss of elasticity throughout the muscle tendons and surrounding tissue.
Because the amount of lubricating fluid inside your joints decreases and the cartilage thins as you age, joint movement becomes stiffer and less flexible. Ligaments also shorten and lose flexibility, causing joints to feel stiff. | 140 | 248 |
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CMV: Artificial intelligence can't become conscious. | I believe that it is not possible for a mere computer program, running on a Turing-equivalent machine, to ever develop consciousness.
Perhaps consciousness is a fundamental force of nature, like gravity or magnetism, in which case it lies outside of the domain of computer science and therefore artificial intelligence. Alternatively, perhaps our brains are capable of [hyper-computation](https://arxiv.org/ftp/math/papers/0209/0209332.pdf), but this is not a serious field of research because all known models of hyper-computers can't exist in our universe (except possibly at the edges of black holes where space-time does weird things, but I think it's safe to say that humans aren't walking around with black holes in their heads). I shall consider these possibilities outside of the scope of this CMV, since AI research isn't headed in those directions.
My reason for believing this was inspired by [a bunch of rocks](https://xkcd.com/505/).
The way we design computers today is totally arbitrary and nothing like how a human brain operates. Our brains are made up of a large network of neurons connected via axons and dendrites which send signals chemically through a variety of different neurotransmitters. Modern computers, by contrast, are made up of a large network of transistors connected via tiny wires which send binary electrical signals. If it was possible to write a program which, if run on a computer, develops a consciousness, then this difference would imply that consciousness likely doesn't depend on the medium upon which the computations are performed.
Computers of the past used to be based on vacuum tubes or relays instead of transistors. It's also possible to design a computer based on [fludic logic](https://en.wikipedia.org/wiki/Fluidics), in which signals are sent as pressure waves through a fluid instead of an electrical pulse. There are even designs for a [purely mechanical computer](https://en.wikipedia.org/wiki/Analytical_Engine). The important point is that you can build a Turing-equivalent computer using any of these methods. The same AI software could be run on any of them, albeit probably much more slowly. If it can develop a consciousness on any one of them, it ought to be able to develop a consciousness on all of them.
But why stop there?
Ultimately, a computer is little more than a memory store and a processor. Programs are stored in memory and their instructions are fed one-by-one into the processor. The instructions themselves are incredibly simple - load and store numbers in memory, add or subtract these numbers, jump to a different instruction based on the result... that's actually about all you need. All other instructions implemented by modern processors could be written in terms of these.
Computer memory doesn't have to be implemented via electrical transistors. You can use dots on a sheet of paper or a bunch of rocks sitting in a vast desert. Likewise, the execution of program instructions doesn't have to be automated - a mathematician could calculate by hand each instruction individually and write out the result on a piece of paper. It shouldn't make a difference as far as the software is concerned.
Now for the absurd bit, assuming computers could become conscious.
What if our mathematician, hand-computing the code to our AI, wrote out all of his work - a complete trace of the program's execution? Let's say he never erased anything. For each instruction in the program, he'd simply write out the instruction, its result, the address of the next instruction, and the addresses / values of all updates to memory (or, alternatively, a copy of all memory allocated by the program that includes these updates).
After running the program to completion, what if our mathematician did it all again a second time? The same program, the same initial memory values. Would a consciousness be created a second time, albeit having exactly the same experiences? A negative answer to this question would be very bizarre. If you ran the same program twice with exactly the same inputs, it would become conscious the first time but not the second? How could the universe possibly remember that this particular program was already run once before and thereby force all subsequent executions to not develop consciousness?
What if a layman came by and copied down the mathematician's written work, but without understanding it. Would that cause the program to become conscious again? Why should it matter whether he understands what he's writing? Arguably even the mathematician didn't understand the whole program, only each instruction in isolation. Would this mean there exists a sequence of symbols which, when written down, would automatically develop consciousness?
What if our mathematician did not actually write out the steps of this second execution. What if he just read off all of his work from the first run and verified mentally that each instruction was processed correctly. Would our AI become conscious then? Would this mean there exists a sequence of symbols which, if even just *read*, would automatically develop consciousness? Why should the universe care whether or not someone is actively reading these symbols? Why should the number of times the program develops consciousness depend on the number of people who simply read it?
To change my view, you could explain to me how a program running on a modern/future Turing-equivalent computer could develop consciousness, but would not if run on a computationally equivalent but mechanically simpler machine. Alternatively, you could make the argument that my absurd consequences don't actually follow from my premises - that there's a fundamental difference between what our mathematician does and what happens in an electronic/fluidic/mechanical computer. You could also argue that the human brain might actually be a hypercomputer and that hyper-computation is a realistic direction for AI research, thereby invalidating my argument which depends on Turing-equivalence.
What won't change my view, however, are arguments along the lines of "since humans are conscious, therefore it must be possible to create a consciousness by simulating a human brain". Such a thing would mean that my absurd conclusions have to be true, and it seems disingenuous to hold an absurd view simply because it's the least absurd of all others that I currently know of.
* EDIT:
A few people have requested that I clarify what I mean by "consciousness". I mean in the human sense - in the way that you and I are conscious right now. We are aware of ourselves, we have subjective experiences.
I do not know of an actual definition for consciousness, but I can point out one characteristic of consciousness that would force us to consider how we might ethically treat an AI. For example, the ability to suffer and experience pain, or the desire to continue "living" - at which point turning off the computer / shutting down the program might be construed as murder. There is nothing wrong with shooting pixellated Nazis in Call of Duty or disemboweling demons with chainsaws in Doom - but clearly such things are abhorrent when done to living things, because the experience of having such things done to you or your loved ones is horrifying/painful.
My CMV deals with the question of whether it's possible to ever create an AI to which it would also be abhorrent to do these things, since it would actually experience it. I don't think it is, since having that experience implies it must be conscious during it.
An interview with Sam Harris I heard recently discussed this topic more eloquently than I can - I'll post a link here when I can find it again.
EDIT EDIT:
Thanks to Albino_Smurf for finding one of the [Sam Harris podcasts](https://www.youtube.com/watch?v=AaNLX71Hl88) discussing it, although this isn't the one I originally heard.
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> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | How do you prove consciousness? We have tests that can be performed, but we must design the test and determine what criteria is needed in order to pass it. Does consciousness have to be biological? Why does it even need to exist from our understanding of it? Why do humans get to set the standard of what conscience is? How can we assume that we're the bar/standard/perfect form of it?
I don't think it's about whether we will create consciousness or not, but whether we can create something that simulates it to a point where we can't tell the difference. Since the human brain is limited with evolution over hundreds of thousands of years, the growth of computing ability certainly will surpass it at some point in the future if it hasn't done so already, just waiting for a good-enough program. It doesn't need to simulate the human brain, it just needs to trick it to beat us.
We can't focus on *how* it was created, or the source of the code. Knowing that fact would change your opinion of whether something is conscious or not, regardless of how well it performs.
It doesn't matter whether humans are truly conscious, or whether computers can replicate whatever that may be. We gradually work on AI improving it iteration by iteration. It doesn't need to simulate a human brain. All it needs to do is to create an output that convincingly matches it. And once we get to that point which is inevitable, it should be able to live-test itself and to further identify weaknesses and improve itself, to the point where it's questioning and testing whether we're actually conscious...
I think the point is if conscience is some objective state that is a binary yes/no, then maybe computers can't reach it, but it can act in a way that we won't be able to tell the difference. If it's a continuous spectrum, then certainly computers will be able to step by step progress to a point where it surpasses whatever stage humans are currently, and continue to develop faster. | 20 | 85 |
ELI5: Why are waiters/waitresses paid below minimum wage in the U.S.? Isn't a tip not a tip anymore when you're essentially paying their living wages and subsidizing the restaurant's payroll? | 1. Servers used to be paid normal wages.
2. People gave them tips.
3. Restaurant owners noticed that the servers got roughly as much in tips as they did in wages. They saw a cost-cutting opportunity.
4. Restaurant owners successfully lobbied Congress to put in an exemption to the federal minimum wage law, citing that servers made plenty of money on tips alone.
5. And here we are. | 71 | 85 |
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Is the Cornell note taking method actually superior to alternative forms of note taking? | I have read that the Cornell method helps stimulate the mind, as it involves more interaction with the written material. Is there any truth to this?
Additionally, why are hand written notes superior to typed up notes? | You are asking questions of subjective experience as if it were objective truth.
The Cornell method requires a certain additional interaction, as you note. Additional interaction is correlated with better retention. That's generally "superior" to just writing things down once, but there are plenty of "alternative" forms that also encourage additional interaction, and good study habits involve additional interaction regardless of note-taking techniques.
Good study requires interaction with the material - reading, interpreting, synthesising. The Cornell style builds that into the note-taking, but there are plenty of other ways to do it, so the Cornell style isn't innately "superior". There are plenty of ways to get that interaction without Cornell. Scribbling random notes down as the lecturer talks and never coming back to them is not one of those ways, however. | 13 | 20 |
CMV: The “Don’t Say Gay” bill does not discriminate against the LGBT community | First, the bill is called “Florida House Bill 1557: Parental Rights in Education”. From my understanding, the part that is the most controversial is the fact that it prohibits the discussion of sexual orientation and gender identity in classroom settings from kindergarten to third grade.
I think this is exactly as it should be. Kids are only 5-8 in these grades. This bill doesn’t limit sexual education in any way as it allows for the typical sex ed classes in middle/high school.
Even if you think discussions about sexual orientation and gender identity should take place prior to middle school, this bill also limits the discussion of heterosexuality and cis gender identity, so this doesn’t harm LGBT people any more than it does straight people. | Sexual orientation and gender identity aren't just or even mostly about sexual intercourse. For example, discussing a person with two fathers or two mothers, a person in a same-sex relationship, romantic feelings, etc would be "banned", all while it's perfectly fine to have the same discussions about opposite-sex relationships.
How is that not discriminatory? | 1,700 | 784 |
How does synthetic food flavoring work? How is it that ,for example, pizza flavored chips sort of taste like actual pizza? | Chemists determine what molecules are responsible for what our bodies recognize as "pizza" or "grape" or whatever flavor they want to duplicate, then either isolate these compounds from natural sources (for natural flavors) or synthesize them from other compounds (for artificial flavors). Often what we think of as "pizza" or "grape" is more than one compound that is mixed together. However, some flavors are very recognizable from one compound (e.g. "grape soda" flavor is methyl anthranilate).
There are lots of laws that govern what kinds of compounds can be used, and what they must be labeled as (natural flavors, natural with other natural flavors, artificial, etc.) that vary from country to country.
Flavor chemistry is as much an art as a science, and flavor companies pay lots for people that are able to blend compounds in the right proportions to duplicate the flavors we taste in nature. A flavor chemist would be an interesting AMA. | 10 | 15 |
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How can railway cables be kilometres long without a huge voltage drop? | I was wondering about this, since the cables aren't immensely thick. Where I live there runs a one phase 1500V DC current to supply the trains with power, so wouldn't there be an enormous voltage drop over distance? Even with the 15kV AC power supply in neighbouring countries this voltage drop should still be very significant. | Part of designing such systems is allowing for fairly substantial swings in actual supply voltage compared to the nominal.
(The IEC 60850 standard, for instance, specifies that a nominal 1500 VDC system is in spec as long as the voltage on the line is anywhere between 1000 and 1800 VDC.)
System design considerations include the selection of suitably-large, low-resistance conductors, as well as regular placement of substations to connect the high-voltage AC grid to the railway's overhead wires. | 2,298 | 3,306 |
How do we know genetically modified foods are safe for human consumption? | Taking BT corn for example. Assuming the necessary animal and human trials have been conducted to demonstrate the cry1Ac protein is safe for human consumption:
This protein is 1178 AA in length, yet the gene it is encoded in is 75 Kb. That would suggest only 4.7% of this gene codes for the cry1Ac protein.
How thoroughly do we understand the structure and function of the other 95.3% of the gene?
Are all the other coding, non-coding, promoter, etc sequences thoroughly studied to make sure no unexpected effects could occur? And what about epigenetic factors?
In my graduate biotechnology course I was told we did not fully understand how most non-coding DNA operated, and we were just beginning to get a grasp on epigenetic mechanisms. If we do not fully understand what these non-coding genes do, how can we say it is absolutely safe for human consumption?
edit: [data source](http://www.uniprot.org/uniprot/P05068) | You are asking the wrong question:
**How do we know that foods which are not genetically engineered are safe for human consumption?**
***
First the GM crops
The only mechanism by which DNA can harm us is by the proteins that it encodes. DNA itself can do nothing, it just gets digested. DNA is DNA no matter it's source.
The proteins that we want a GE organism to express are very well understood. That is the point of selecting them.
The plants then are tested extensively for allergens and if there is even the slightest chance somebody could be allergic to the protein, then it doesn't get approved.
***
For non-GM crops
No testing is done with non-GM crops and some of these are lethal to some people, such as peanuts.
There is no guarantee that a traditionally bred plant isn't poisonous, after all 1000s of genes are being modified, and none of these are tested.
Many hybrid plants are mutagens, that is they were created by radiation, chemical or other type of mutating agents. Again 100s of genes can be altered in random ways. These are also untested and many are grown as "organic".
***
**So ask yourself, why can a person use radiation to randomly alter the genome a plant and it is ok to sell that as organic without testing. But if a scientist changes a single gene in a lab, then it suddenly requires major legal and regulatory hurdles?** | 18 | 16 |
ELI5: Why does Catalonia want independence from Spain? | Catalonia is a culturally and linguistically distinct group. The Catalonian language is actually very different from default Spanish or its regional dialects.
Plus, the economy in Catalonia and especially Barcelona is in much better shape than the rest of Spain, so the locals feel it's unfair that they have to pay taxes to central authorities that then subsidize other regions. | 44 | 68 |
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ELI5: How do scientists detect the DISTANCE of source of radio waves coming from different regions of universe? | Simply: Light stretches and the further away something is, the more the light stretches
Less simply:
Waves stretch in accordance to how fast an object is moving towards/away from you, called the doppler effect.
To gauge distance, we must first relate the specific waves (as objects emit more than one, this is very important) to an object. The detected wavelengths are then matched to an existing similar object that is not moving relative to earth.
Using the mathematics of the doppler effect, we can form an estimate of how fast an object is moving away from us. From there, it is possible to estimate the distance from you to the object. This is because there is a natural law in the universe where objects are moving away from you faster the further away you are from it.
Also, different light wavelengths stretch by the same amount for a unit of speed, so the detected spectral lines just need translating to the left or right. | 90 | 342 |
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ELI5: When looking at a flame, what exactly is the orange part? How does flame work? | Everyday combustion, like burning a candle, involves carbon and other chemicals in the combustible material reacting with oxygen in the air. This reaction is exothermic, meaning that it gives off thermal energy, or heat. Given enough heat, electrons in the atoms off the gas start to become excited, ie they reach a higher energy level. This arrangement is unstable, and the electrons will collapse back to their previous energy level, and in doing so they will release their excess energy as electromagnetic radiation. The wavelength of this radiation is determined by what you're burning and how much energy the combustion released, but for everyday materials like wood and candlewax, the wavelengths will be long enough to produce visible yellow, orange and red light as well as infrared light, which you can feel as heat when you get close to the flame. | 10 | 15 |
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How did Henry Cavendish manage to calculate the Earth's mass back in 1798? | Basically, he created a balance that was able to isolate and measure the gravitational force between two small objects of known mass. From there, he was simply able to weigh one of the objects (aka measure the gravitational attraction between it and the Earth) and compare the magnitude of the force between the two small objects and one of the small objects and the Earth. The ratio of the force on the object from the other object of known mass to the force on it from the Earth allowed a calculation of Earth's mass. | 17 | 15 |
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ELI5: What actually changes in your body when you build cardio endurance? | How does endurance actually work? Why do you have to actually run to gain endurance for a marathon instead of just doing strength training? What changes in your physiology when doing endurance training besides getting muscular? | Endurance comes from a process that converts glucose and oxygen into energy.
There are many steps in that conversion process, and each of them gets optimized in a certain way.
A top endurance athlete will have more red blood cells to carry oxygen, a bigger heart muscle to pump the blood faster, and more mitochondria (the little furnaces that combine glucose and oxygen) inside each cell.
There are other adjustments as well, but those three are the most important. Note that none of these adjustments involve any physical change in the size of the muscles, other than the heart.
As for strength training, that primarily involves an energy pathway that does NOT use oxygen. Bigger muscles will not help much with endurance, as long as the athlete has enough basic strength to keep the body stable. Otherwise, big muscles just end up as added weight and bulk that can slow down an endurance athlete. | 24 | 46 |
ELI5: How are random numbers generated by computers? | I've heard they're not truly random, but I don't know how that would work either, because they obviously appear random. | Computers use special math functions to generate random numbers. You know what a function is, right?
for example:
f(x) = x^2
When you plug in 3 to this equation you get
f(3) = 3^2 = 9
The functions computers use are much more complex. also, knowing the input number generally doesn't help you figure out what the output number is going to be. In the above case we know certain things about the output number. It's going to be a square number, it won't be prime, it will be larger than our input... etc.
Alright, so the random numbers come from the output of this magic function. Where do the input numbers come from? Usually the function will use the *last* random number generated to produce the next random number.
So you may ask "where does the *first* input come from?". Good question. That depends on the programming language and the programmer. If the programmer doesn't give the computer one, it may just start with 0 or 100 or some other constant number. This produces a problem though. If you were to run this program multiple times, the "first" random number would always be the same so the pattern of "random" numbers would always the the same. Not very random, huh?
So there are some tricks programmers use to generate a good "first" random number. The most common practice is to use the current time as the first random number. As long as the program runs at different times, the generated numbers will be random.
Alternatively, the programmer may use something human generated (like the last movement of the mouse or the time since the last keyboard key was pressed) to generate the first random number.
One final method. There is a web site called www.random.org which is dedicated to producing "true" random numbers (randomness is actually a super interesting topic, but kind of outside the scope of your question). random.org grabs atmospheric data to produce numbers... it's kind of like they are sitting somewhere rolling a bunch of dice. It's "more" random than what computers do because no function or set of rules is being followed to generate the numbers.
| 16 | 27 |
ELI5: Why can quitting drinking kill an alcoholic? | With heavy/long-term use, alcohol creates big changes in the alcoholic's brain chemistry and body. When an alcoholic suddenly stops drinking, the brain's systems basically go haywire with the sudden change. Areas that were constantly excited by the constant alcohol are now pretty quiet, and other areas that were constantly quieted by the alcohol "wake up" and freak out, leading to seizures, heart strain, shaking, anxiety, etc. While that alone can be fatal, if the alcoholic has other health issues, the extra strain on the body can cause problems there and lead to death, particularly with underlying heart issues.
As an aside, a friend was just talking about this the other day and said that quitting alcohol is so dangerous compared to quitting other drugs because of how deeply the alcohol penetrates into the brain. Other drugs are slowed/stopped by the blood-brain barrier, remaining mostly on the surface of the brain or in the bloodstream, but alcohol is able to pass through. | 61 | 105 |
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Can someone explain to me why Plato's work isn't terrible? | To elaborate on the title,
I understand that Plato was vital to the development of philosophy, and that he has incredible historical significance. I think that through a historical lens, all of the praise that Plato recieves is justified—he was ahead of his time. That being said, I'm completely dumbfounded as to why people would ever, ever recommend Plato for the actual content of his writings, devoid of their historical context.
This is an exerpt from Republic, Book I, starting from 333e:
*Socrates: "Then, my friend, justice cannot be a thing of much worth if it is useful only for things out of use and useless. But let us consider this point. Is not the man who is most skilful to strike or inflict a blow in a fight, whether as a boxer or elsewhere, also the most wary to guard against a blow?”*
*Polemarchus: “Assuredly.”*
*Socrates: “Is it not also true that he who best knows how to guard against disease is also most cunning to communicate it and escape detection?”*
*Polemarchus: “I think so.”*
*Socrates: “But again the very same man is a good guardian of an army who is good at stealing a march upon the enemy in respect of their designs and proceedings generally.”*
*Polemarchus: “Certainly.”*
*Socrates: “Of whatsoever, then, anyone is a skilful guardian, of that he is also a skilful thief?”*
*Polemarchus: “It seems so.”*
*Socrates: “If then the just man is an expert in guarding money he is an expert in stealing it.”*
*Polemarchus: “The argument certainly points that way.”*
This point is later ended by the following dialogue:
*Socrates: So justice, according to you and Homer and Simonides, seems to be a kind of stealing, with the qualification that it is for the benefit of friends and the harm of enemies. Isn't that what you meant?”*
*Polemarchus: “No, by Zeus,” he replied. “I no longer know what I did mean."*
Do I really need to point out how lazy and absurd this conclusion is? The relationship between a skill and an inverse skill just doesn't apply to moral values or personality traits—"justness" is not a profession. The most introverted person is not also the best at being extraverted. The most charitable grandmother is not the best at being selfish, etc.
I don't want to harp on too long about this particular exerpt, but I think it does a good job of encapsulating the formula of the arguments in Plato's work—Socrates draws shifty comparisons to prove or disprove a point, they often go completely unchallenged by the braindead strawmen that he's arguing with, and at the end they're left speechless.
There are obviously good bits here and there, but the overwhelming majority of Plato's works read like some fantasy he had in the shower of what he *wished* would've said in an argument he had a couple of years ago and can't stop thinking about for some reason. Am I just crazy here? | Plato's dialogues are a fairly accessible way of showing philosophy being done as an activity without relying on any prior knowledge of philosophy or any technical, specialized terminology.
And, in the dialogues, Plato pretty much maps out the general landscape of all philosophy to come, even if Plato's own theories are disagreeable and his characters flimsy. Like, yeah, *anamnesis* sounds like a silly theory to a modern reader but it's not hard to see how it foreshadows the discussion of innate knowledge ever since and into today's sciences of the mind. | 212 | 123 |
CMV: Democratic countries should have a voting system where voters can vote for as many candidates as they want | I have a couple reasons for why this is the best way to vote for any head official, like a president or prime minister.
I guess I should say how this would work though first.
So on the ballot there'd be around 5 blank lines for you to fill in candidates, you can fill in as many candidates as you want or as few. Each candidate you put on the ballot will add one vote to said candidate. If you put the same candidate twice it'll still count as only one vote.
Once all of the ballots are collected and counted the candidate with the most votes will win the election.
Here's and example to what this would look like:
There's a country with six million people in it and three candidates running, their names are 1, 2 ,3. This is country that is mainly a two party system where 1, 2 represent the two main parties that always get the most votes in a first past the post* vote and 3 represents more of a party on the middle of the political spectrum. The people vote and here is the result, 1 got three million votes, 2 also got three million votes, and 3 received 4.5 million votes and won the election.
Here are the reasons to why I believe this is the best voting system.
1. People would be able to for the party they most agree with even if that party isn't very popular or well known.
2. The candidate that the most people would at least tolerate would get chosen, thus more reflecting on the views of the country.
*In case you don't know first past the post is the voting system most countries use, 1 vote per person.
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> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | This voting system can lead to paradoxical outcomes where almost everyone prefers candidate A to candidate B, but nevertheless candidate B wins the election.
For example, suppose that there are three candidates, A, B, and C, and three kinds of voters.
The first kind of voter prefers A over B, and B over C. Additionally, these voters consider A and B tolerable, but not C, so they vote for A and B.
The second kind of voter prefers C over A, and A over B. These voters vote only for C.
A third, minority group prefers C over B, and B over A. These voters vote for B and C.
Now suppose that 80% of voters are in the first group, 15% of voters are in the second, and 5% are in the third. This means that A will receive 80% of the vote, B will receive 85%, and C will receive 20%. B will win the election. This is despite:
* The fact that a majority of voters, 80%, prefer A over all other candidates.
* The fact that almost all voters, 95%, prefer A over B.
* The fact that literally no voter prefers B over any other candidate.
This sort of pathological result makes your system undesirable.
| 17 | 26 |
CMV: I am of the strong opinion that capital letter should not be required at the start of a sentence. | capital letters fulfill their purpose in acronyms/initialisms and proper nouns. a name like Mark requires a capital to differentiate it from the regular word. capitals are not required to show a reader that a new sentence is beginning. the entire point of punctuation is to end a clause. a comma or semi-colon is not followed by a capital, because people are able to understand the with the punctuation alone that the ideas are separate. there are some debatable uses, like capitalizing titles.
TL;DR: capitalization has some uses, but starting a sentence with a capital is unnecessary, and should be left behind. | Capital letters fulfill their purpose in acronyms/initialisms and proper nouns. A name like Mark requires a capital to differentiate it from the regular word. Capitals are not required to show a reader that a new sentence is beginning. The entire point of punctuation is to end a clause. A comma or semi-colon is not followed by a capital, because people are able to understand the with the punctuation alone that the ideas are separate. There are some debatable uses, like capitalizing titles.
You may have a point. But which style was easier to read...? | 50 | 24 |
ELI5: Why can things like optical illusions “trick” our brain, even when you know for a fact what the reality is? Why is “what your brain thinks” not equal to “what you know”? | Our brain is HEAVILY optimized for pattern recognition and prediction. It happens without our even being aware of it.
So when something breaks set patterns that we're used to, that pattern has already been recognized and predicted by our brains well before we get to the point of conciously pondering the issue.
A lot of our thinking happens without us "thinking" about it at the level of a conscious internal monologue. It's the same place we get gut feelings we can't explain because they happen below that monologue level. | 22 | 26 |
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ELI5: If cat's and dog's hearing is so much more sensitive than human hearing, why are they not bothered by things such as traffic noise or TV noise? | I was thinking about this the other day when I was watching TV the other night and my dog was happily dozing next to me even though the TV was a bit too loud for me. | Cats and dogs can hear a wider range of sound frequencies. That does not necessarily mean that they will experience noice to be any louder then what we experience it to be. Also, dogs tend to not give a f*ck. | 53 | 52 |
What is the connection between critical theory and critical race theory? | As far as I can tell, they seem to be completely separate things. Some proponents of critical race theory seem eager to dismiss any connection between CRT and Marxism, presumably to anticipate and counteract some of the conservative conspiracy theories claiming that CRT is undermining Western Civilization (often through it's association with \*shudder\* Marxists. At the moment, I'm not really concerned with the conspiracy theories one way or the other, I'm just trying to understand what the two terms (CRT and CT) refer to and what, if anything, is the link between them.
So are these fields totally distinct? Is there a lineage from one to the other? Is there much overlap between the two in their contemporary instances? Does the "critical" in "critical race theory" mean the same thing it does in "critical theory"? What exactly is the connection here? | First, there's a difference between 'Critical Theory' as referring to the Frankfurt School body of work, which is Marxist, and 'critical theory' which comes out of this work but is not necessarily Marxist. It's by equivocation that conservative critics make the charge that critical theory is Marxist.
A critical theory seeks "to liberate human beings from the circumstances that enslave them. (Horkheimer 1982)," but this doesn't necessarily entail a commitment to Marxism, either in general or any specific way, nor a repudiation of it.
The connection between critical theory and critical race theory is critical legal studies, which is critical theory applied to law. Critical race theory came out of critical legal studies by focusing on the ways in which race works within laws to maintain racially-discriminatory power structures.
Critical theory is not a body of knowledge but an approach which challenges power structures, be it in states which are capitalist, socialist, autocratic, democratic, or whatever else. The connection is in the critique of power structures in the interest of liberating human beings from the circumstances that enslave them. In this way, critical race theory is critical theory applied toward the role that race plays in laws which perpetuate racial injustice, and this is done in the interest of reform. | 95 | 83 |
ELI5: Why do the spouses of celebrities get so much money in the case of divorce when it's clear they wouldn't make near so much money had the relationship never happened? | In the eyes of the court, a marriage means two people becoming one person.
Imagine a blue crayon marries a red crayon. The law no longer sees them as two separately colored crayons but as one purple crayon. A divorce would be like breaking the crayon in half. It doesn't turn back into a red and blue crayon but, instead, is two broken halves of a purple crayon.
I could explain it much more precisely, but you did come to ELI5. | 1,135 | 536 |
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Why are the primary colors for light different from the primary colors for paint? | In light, all colors come from green, red, or blue. In paint, all colors come from yellow, magenta (almost red), or cyan (almost blue). What is the reason for this difference? | The difference is that light is additive, while paint is subtractive. I'll try to explain.
If you mix all the colors of light, what do you end up with? White light. But if you mix all the colors of paint what color do you end up with? Black paint. This is the primary difference. With light, you are mixing wavelengths together, adding them up to some color. With paint, you are removing colors. For instance, red paint absorbs all wavelengths except for red. And if you have green paint, it will absorb all wavelengths except for green. So, mixing them together, you will absorb all wavelengths.
This is why with light you want to use the primary colors- colors which are a single wavelength, while with paint you want to use secondary colors- colors which reflect multiple wavelengths. For instance, yellow reflects red and green, while magenta reflects red and blue. So, mix yellow and magenta together, and you'll get red (since yellow absorbs everything but red and green, magenta everything but red and blue, leaving only red). | 136 | 128 |
ELI5: What causes “the chills” when you’re sick? And why do they sometimes alternate with “the sweats”? | When you develop a fever, your brain turns up your biological thermostat, increasing the setpoint of your core body temperature.
When that happens, your previously normal body temperature feels cold, and your body responds accordingly by shivering to increase your body temperature to the new setpoint. It also restricts your blood vessels to shunt blood deeper into your body, giving the characteristic chill sensation.
The sweats occur when that thermostat is dialed back to "normal"- suddenly, your increased body temperature is now too hot and your body compensates by sweating to radiate that heat away from your body as fast as possible. | 29 | 26 |
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ELI5: How do they find out the information that goes on Nutrition Facts labels? | Like number of calories, fat content, vitamin content, etc. etc. | There's a database of ingredients that has nutritional info for a variety of foods. When you make up a recipe you figure out the amount of nutrients and calories based on how much of each ingredient was used.
For each ingredient in the database, they dried out the food and burned it and measured how much energy was produced by the burning. The tool is called a calorimeter, and it's more or less an insulated box where you burn stuff in the bottom and have a bowl of water on top and measure how much the water temperature goes up (1 degree per cubic centimeter is a calorie).
For everything else, like vitamins, etc., they've worked out chemical procedures for separating out the materials in the food (generally by mashing and pouring a solvent over it and the pouring through a tube filled with special sand calleda "column"). They use special instruments that can identify the molecules and how much there is (the exact technique varies depending on the material).
The important part is that they don't run these tests on every food, just the basic ingredients. You can work out the nutritional content based on the recipe. Mind you, some of the cooking or processing might affect the nutritional content, so, in some cases they've tested foods cooked different ways. It's always an educated guess because foods vary in their nutritional value based on all sorts of things (like when it was harvested, how well it was watered, etc). | 151 | 291 |
Why does sweat have so much salt? | From a biological standpoint, why is salt excreted in sweat along with water?
From an evolutionary standpoint, why did sweat evolve to be an excretion of salt and water when potentially it could have evolved to be just an excretion of water? | From a chemical viewpoint, salt is excreted along with water because excreting water alone would increase the osmotic pressure inside the body (less water but the same concentration of salts, sugar etc. means the solutes become more concentrated), which would actually draw water back into the skin because of the concentration gradient. Evolving to excrete salt/water together means more water can be removed to allow for evaporation and thus cooling. | 16 | 38 |
CMV: "Rules as Written" when it comes to D&D and other tabletop games doesn't mean much, and DM's in fact *should* go through the rules and change anything they don't like. | So players in tabletop games like D&D like to talk about the rules, ways to break the game, etc, and often they'll use the phrase RAW or "Rules as written", but I think it's kind of pointless to argue this. D&D has always emphasized that DMs should change any and all rules that they want to.
I've been watching some funny youtube videos where people talk about "overpowered" spells, ways to break the game, best "combos", etc. And while they're funny, I'm also taking notes on what to change in my own game in order to prevent this kind of powergaming.
This brings me to another point that I wanted to include in the title (but it was already clunky) - even D&D 5e, arguably the most "streamlined" and "munchkin-proof" edition yet, is still written by mere mortals and has its share of balance problems. I think this is mostly due to the fact that the creators can't imagine every scenario, and sometimes they just make little mistakes, like allowing players to summon creatures that can polymorph them into killing machines for a long period of time.
In fact, I think the videos on youtube that show these kinds of balance issues should be used to construct a sort of "community patch" which could list out these issues and ways to correct them.
Maybe what I'm saying doesn't seem very controversial, but I know a lot of players can be "rules lawyers", so maybe it is. But I think each roleplaying system isn't perfect and needs a significant amount of tweaking from creative players and DM's to be brought to its fullest potential, there's no need to wait for new editions.
edit: I'm not talking about secretly changing the rules without telling your players, I would discuss the changes with them beforehand. | RAW is important because it is consistent. It is the base upon which any set of house rules is built. If there is going to be any discussion of how the game should play or be played, it will necessarily be in the context of what in the RAW does or does not work for a given group/DM.
A community patch also seems like a strange way to approach what you see as problems with the system. RAW is the base, and groups can and should modify them to suit their needs, but the needs and desires of each group are too varied for there to be some magical set of house rules that will improve the game for everyone.
Some groups want games that are more powerful. They let people roll stats in ridiculous ways, give them bonus feats and skills in character creation, and implement powerful variants like spell points, or allow incredibly powerful homebrew classes and subclasses.
Some groups want to emphasize exploration or some non-combat pillar and outright ban several spells and background options that can trivialize this like outlander and goodberry.
Some groups want to trim back the power of the optimized damage per round builds, and therefore ban or change the feats these builds make strong use of.
There can't be a real community patch to the game when there is no "community way" to play the game. Every groups modifications should be specific and to suit their needs and playstyle. To understand what those changes might be, it is important to discuss and understand RAW, so you can make informed decisions about what to change and why. | 27 | 95 |
[ELI5] Why do most software programs (web browsers, for example) display an error code that you have to look up instead of just telling you the error? | The use of error codes is considered a good practice in programming, because it allows different errors to be strictly defined and distinguished from one another. The name and explanation of that error can then be easily localized.
For example, HTTP error "404" has a detailed specification indicating when it should be issued. It happens to be called "Not Found," but a web site may choose to return a page with a different name and an easy-to-understand explanation if it wants to. Or a browser can choose to provide that information, even translate it based on the user's language. Either way, behind the scenes the web server and browser both understand just what is meant by "404." | 47 | 135 |
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CMV: Most Employers and the Military should be allowed to discriminate genders for physical/biological reasons | Science has proven that men and women are physically different from each other. Men tend to be stronger, larger, and faster while women tend to be more flexible, shorter, and more slender. Many jobs that require the employee to perform physically which in most cases mean that men would be better because of their tendency to be stronger. In the military, the PT standard for women is lower than that of men meaning that if everything else was equal, they would get the same job. Additionally, women can become pregnant which would mean they wouldn't be able to work for several months. However, I also think that employers should not be allowed to discriminate if the job has no relation to physical performance, like a basic desk job.
Change my view
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> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | You're saying that they should be allowed to discriminate based on gender because there are differences in strength, on average, between genders. What you're neglecting is that the variation is pretty high. Not all men are stronger than all women. Why should employers be allowed to discriminate based on gender and hire a weaker man over a stronger woman?
I think your argument is better suited for the thesis "employers should be able to discriminate based on strength, regardless of gender." | 122 | 50 |
[Digimon] Was Angemon some sort of anomaly in the digiworld or digital code that made him so strong? | Angemon was his in champion form, but he was by farther stronger than any other Champion. He could even rival and defeat many Ultimates in his champion form. I read in the Digimon archives that the only Digimon Angemon is unable to defeat are those who are of the Mega level. And even then he could at least hold his own. And then when he turned into MagnaAngemon. It was game over man. | You may recall that there are 3 designations of digimon, vaccine, data and virus, and they have varying effectiveness of each other (vaccine > virus > data > vaccine) . Angemon (and others of his line) are a little special in that they take this to the extreme, being incredibly effective against virus digimon, especially those themed after demons or devils (who are themselves typically a bit more powerful than normal), explaining the disparity of power in the shown scenarios. The price for this is difficulty fighting other types(morally and power wise), and overall difficulty of digivolution. | 124 | 231 |
ELI5: Why are the elderly so susceptible to scams which are incredibly obvious to younger people? | I get that some of it is technology, but in general, why do old people seem to be more likely to believe an appeal of "something for nothing"? | You mean like student loans and college?
I keed.
Everyone is susceptible. We probably only hear about it more in regards to the elderly 1) because it's sad, 2) grifters know they have money, 3) the elderly might just want someone to talk to, and 4) your mental faculties wane as you age. | 30 | 38 |
CMV: Individual efforts have no effect on global-scale problems. | For example, say a person stops eating meat due to a belief that cultivating it leaves too large of an environmental footprint. If this is an average person with an average amount of influence over the people around them (i.e. not a celebrity), this would not make a difference whatsoever on the amount of meat that will continue to be grown for consumption. Yes, it would make a statement to the people around them, and draw more attention to the problem at hand, but in the large scheme of things, it would make absolutely no difference whether or not this person consumes meat.
A much more effective strategy would be to use their collective influence and manpower to try and change legislation, rather than trying to make others feel guilty for not following their ideals.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | I'd say instead that individual efforts have a *negligible* effect. Taken purely on an individual basis, then yes, the efforts of one person will have no apparent effect on large scale problems. However, when viewed in a broader context, there are no large scale efforts that are not carried out by individuals. The individual is the base unit of any other larger collective effort.
Therefore, if only large scale efforts have an impact, and such large scale efforts are the collective sum of individual efforts, then the logical conclusion must be that individual efforts are perhaps the *only* thing that can effect wide-scale change.
To further address your post, the collective efforts you describe still resolve to a base unit of individual persons. Armies only work when soldiers follow orders. Political movements only exist when numerous individuals voice support in unison. Legislation is only as effective as the individuals who carry it out. | 14 | 16 |
ELI5: Why is it so difficult for computers to truly randomly generate numbers? | Computers are just calculators; they do mathematical operations. Because of the nature of mathematics, you can't use simple math operations to generate truly random values -- math is inherently deterministic. However, you could design a function that is so complex that there's no immediately noticeable pattern in the numbers it generates. This is what computers do to generate random numbers. There is a tradeoff with different generator functions between speed and randomness, and depending on your needs you might choose different functions.
EDIT: it IS possible to generate random numbers by measuring something that is extremely complex, to the point where it is impossible to predict. For example, you can generate a number based on the amount of heat/electrical interference in a wire at a specific point in time. | 32 | 57 |
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ELI5: Why is ancient Mesopotamia described as a lush land but (the most equivalent) modern Iraq is mostly desert? | I've never been to Iraq and I know that the two regions don't exactly overlap, but still I'm surprised that a country that today is described as mostly desert in the past was the perfect area for agriculture and human wellbeing. | Civilization formed on riverbeds and river-valleys. Even modern day Iraq has plenty of lush areas fit for agriculture near rivers and sources of water: it's not all desert.
The cradle of civilization formed between the Tigris and Euphrates Rivers, meaning water was easy to get. The same was happening around the Nile, which floods with incredible regularity causing agriculture planning to be very easy for early civilization.
Additionally climate changes (not *that* climate change) is a thing. The Sahara desert for instance isn't a permanent desert, it has trough the lifetime of the earth flipped between being a desert and being covered in grasses, forests, and lakes as the African humid period went on. It's not impossible to think that the area you're referring to at one point had a very different climate. | 160 | 166 |
How do I not get too emotionally invested in a paper I'm writing? | I have final papers coming up in addition to a writing sample for PhD applications in philosophy and I realized that a major stumbling block is that I am too emotionally invested in my paper (both the topic and the outcome of my thinking) and it is getting in the way of my ability to complete it on time.Does anyone else have this issue or any tips on how to overcome it?
Edit: By emotionally invested I mean partially that so much of me getting in to a program hinges on the writing sample being good that it interferes with my writing.
But also (and the more general question) that I am super interested in and care a lot about the topic of the paper and I want to do justice to it and be up to date on the literature and have it be the most accurate portrayal and answer of the topic that it can be, but I don't have enough time to do it justice. So I feel paralyzed between the two. | No matter the point in your academic career, you'll have to "let go" of a manuscript so that it can be reviewed by editors/peers.
No matter the excellence of your argument, no matter how much time you've focused on perfecting it, other eyes will view it in potentially different light(s). Other minds will think on it from different perspectives, backgrounds, interests.
And you'll get feedback on that. Sometimes really positive, supportive, fantastic ideas. Sometimes reviewer 2 ruins your whole week or month.
But no matter what, it has to leave your hands and go out into the world. And you have to come to terms with letting go so that it can be strengthened as a result. | 19 | 23 |
CMV: It shouldn't be illegal or frowned down upon to sleep in your car! | When I was single I was considering living in the back of my Suburban. It's a nice place to sleep. I usually eat out anyway. 24hr gym membership for showers. Laundromat for laundry. Park in a quiet spot near work (or in work parking lot) for a short commute (if you have a regular job) or just hang out at Starbucks or somewhere else if you freelance (web design or whatever).
Thing is, it's often illegal, and if it isn't, it's definitely frowned down upon. Tell somebody you live in your car and they'll think your a homeless loser! They don't think of somebody who is simply saving a lot of money on rent to either invest in their savings for retirement or to start their own business or whatever. Let's face it - most single people rent a home or apartment just go to get home from work, eat, and go to sleep.
Sure, there is some problem with people who live in their cars/RVs/vans being loud, doing drugs, and leaving trash or excrement everywhere, but that's not everybody. A nice looking Suburban with tinted windows wouldn't bother anybody parked along the street or in some random parking lot that nobody is using at night anyway!
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Parking spaces are made available for a specific purpose. If you are living in a parking space, then you are using someone else's property in a way they don't want. You could rent out space on a camp ground or trailer park to live in your car legally.
The core idea here is that *you don't own the property*. Just because nobody appears to be using it at the moment, doesn't give you a right to it. You are saving money at the expense of other people. | 202 | 612 |
ELI5: ARM (RISC Architecture) vs. x86-64 (CISC Architecture) | Is this the reason why operating systems have to be created specifically for ARM processors?
I got my first Raspberry Pi the other day and was just curious. It has an ARM processor so the Linux distro's have to be designed to run on the ARM architecture, correct? This is why I couldn't download Ubuntu and run it off of my ARM RPi, since Ubuntu does not make an ARM compatible OS?
How does the CISC and RISC architecture come into play? They process data differently?
I tried reading even wiki pages but was quickly overran by information I couldn't understand. | Computer processors work on instruction sets, which are basically commands that tell the processor what to do. An example might be a command to move a value in to memory, or a command that multiples a value in one memory address with the value in another memory address.
When operating systems are created they are usually created in a higher level, more complex programming language (usually C). For the processor to understand these instructions, a piece of software known as a Compiler needs to take that code and translate it in to machine code that the processor will understand.
There are two main types of processor architecture as you identified - CISC (Complex Instruction Set Computing) used by x86 processors and RISC (Reduced Instruction Set Computing) used by ARM processors. CISC is designed to make complex operations easy for a programmer to achieve, giving greater flexibility and more features, but requiring more transistors on the chip (and therefore physically larger processors) and more power. RISC is designed with a simple instruction set that doesn't offer the same flexibility or number of features as CISC processors, but requires less transistors, less power and physically smaller processor packages.
Due to the entirely different capabilities of the two architectures, its not just a case of re-compiling an operating system for a different architecture. The difference in features usually means that an operating systems kernel will need to be re-written. For example some of the security features available in the CISC architecture are not available at all in the RISC architecture, meaning that if the Ubuntu kernel took advantage of those security features, they would need to be re-written and emulated in software on the RISC architecture.
RISC based (ARM) chips tend to be used in small, low power devices such as smart phones due to their low power usage, low footprint and relatively low cost - hence their use in the Raspberry Pi. | 19 | 17 |
CMV: If someone truly believes that abortion is murder, then that person is justified in non-violently protesting legal abortions. | **READ THIS EDIT:** Apparently I didn't explain myself very well, Here's a re-wording of my belief: **Given that someone believes that abortion is murder, there is nothing you can say to them that can convince them, logically, that abortion should be legal.**
First, disclaimer: Legally speaking, I am pro choice, and I support very open access to abortion services. I don't think that abortion is murder (or at least, I don't *think* I think it is), mostly because I believe it's impossible to make a morally sound judgment on the matter. When does a fetus become a human? I've been debating that question internally for years and years. So regardless of my political beliefs regarding abortion, I have a hard time supporting it on moral grounds. (This is very personal for me, though; I have never told someone that I think their abortion, or their idea about abortion, is wrong. That's insensitive and rude, at best.)
Here's what I *do* believe, though: If someone truly believes that aborting a fetus is, in fact, murdering a human being, then their protests against a system that allows that to take place are justified.
Here's a sample of the logic:
* A person believes that a human being is a living person beginning at conception.
* Killing a person is murder, so they have no choice but to conclude that abortion is murder.
* The government provides abortion services (which are not limited to life-threatening cases), so they have no choice but to conclude that their government sanctions and funds murder.
* Anyone supporting legal access to abortion would be considered in support of a government that encourages the choice of a parent to murder their child between its conception and its birth.
To other pro-choice folks, this might look somewhat ludicrous. But I don't think there's a decent logical, philosophical, or moral argument that would argue that abortion is *always* OK, or that a fetus is *never* a person until its birth. Believing that a fetus is a person, and that abortion is murder, are valid ideas. And given that someone believes those things to be true, then it's understandable that they would feel obligated to stand up and say something. In the same way that you might wish terrible things on a leader who condones hurting and murdering certain groups of its citizens, they might see some of our leaders as condoning hurting an incredibly vulnerable group of people, one that they believe must be protected. They shouldn't be faulted for that.
**Edit:** I should add that in cases where a mother's life is being threatened, and terminating the pregnancy can save her life, you're basically making the choice between two people's lives, and I think it's understandable to preserve the life of the one who already has agency. I believe abortion is always justifiable in that situation.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Clarifying question: I've never heard significant arguments that non violent protest against any topic (abortion-related or otherwise) should be prohibited or was unjustifiable.
What exactly are you arguing against here? | 15 | 25 |
How are demand curves empirically estimated in practice? | How can we hold consumer tastes constant in a regression model? What is the most practical way to estimate a market demand curve for a particular product?
I'm very interested in hearing personal experiences with regards to this (if anyone has had any, that is). Feel free to go into detail when it comes to invoking statistics. | One of two ways:
1. You are the firm selling that product and do small price experiments.
2. You use observational data and use instrumental variables as random quasi-experiments. That is, you want to get data on some variables that affect the supply of the product but not the demand (e.g., cost shocks). Then you use two stage ordinary least squares. There are more sophisticated methods that take lots of things into account. For example, you can also use structural multinomial choice models, adjust for measurement error, include random coefficients, and so on. But any method that you use will require instrumental variables that shift supply without affecting demand. | 40 | 78 |
ELI5: How does colored cloth retain its dye? | Sorry if this was already asked before, but as per my research, it hasn't. How does cloth retain its color? Especially in the washing machine. How can cloth be uniformly colored? This is something I have been wondering about for a while and was wondering if this community had any knowledge about it. Thanks for your help! | There are many different types of dyes (acid, azo, cation, mordant, sulfur, natural pigments, etc) with varying degrees of colorfastness.
The two strongest and most colorfast types of dyes are azo and reactive dyes. Reactive dyes react when they come in contact with the fibers, creating a new compound.
Azo dyes are similar, they use dye coupling to create the compound. The fabric is soaked in one chemical, and then a different one. The two chemicals react, creating the azo dye in the fabric.
With both these types, the dye is created inside the fibers and bonded with it, making it permanent, in contrast with traditional methods of dyeing - soaking fabric in a pigment and using a mordant to help it hold on to the fibers. | 10 | 36 |
Why do smartphones know the answer to (170!) but show as infinite the answer to (171!) ? | Computers (including smartphones) typically store numbers in variables of a fixed size. That size determines the range of numbers that can be stored. For example, a variable that uses 1 byte of memory can have 256 different values, so it can store numbers from 0 to 255 (or from -128 to 127).
If a calculation yields a result that "doesn't fit" in a variable, then several things may occur. Typically the variable "overflows", that is that it simply starts counting from 0 again. In this scenario, the sum 255 + 2 would give the result 1 if variables are single bytes (the result is obtained by incrementing 255 twice, the first increment should take it to 256, but this is outside the range so it overflows to 0, the second increment takes it to 1).
Well-designed software can recognize when this occurs and instead of displaying a seemingly incorrect outcome, it will simply display an error, or infinity. This is to let the user know that the outcome does not fit into the variable size that the program uses.
In the case of the question, 170! is the largest faculty that still fits within a 1024 bits (128 byte) number. 171! is just too big.
Note that there are tools to allow software to work with arbitrarily large numbers. These typically allocate more space for storage as the number gets bigger. They're often quite a bit slower than fixed-size numbers and since such large numbers are rarely needed (in many cases, a computation can be reordered to avoid having such a large number as intermediate outcome), most software simply uses fixed-size numbers and will display an error in the rare situation that an overflow occurs. | 10 | 29 |
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CMV: Nationality is a pointless and detrimental sentiment | When I refer to nationality in the post, I'm referring to strong feelings of nationality mostly. I'd appreciate it if anyone who isn't a strong patriot does explain what kind of sense of nationality they feel and why
Okay, so my logic is that the sentiment that `since I happen to be born on this part of the earth, I pledge my everything to it` is absurd to me. And it's, imo, detrimental to the development of science\* and the progress of humanity. For instance, I live in India and I've been trying to promote a conference called PyCon Pakistan, and I've gotten a few messages saying that `you shouldn't promote it, you're an Indian`, which is an awful sentiment. I want a flourishing python community in Pakistan too, but this feeling of nationality prevents lots of people from engaging in helpful activities like the above.
Now, I understand that lots of people have this very strong feeling and I really do want to understand what motivates them? Like, objectively. What makes the country you were born in better than others? If you just happen to be born in another country, would you love it just as much as you do yours right now? If so, doesn't that mean that your sense of nationality isn't objective?
*I do acknowledge the fact that science in wars does advance much faster, like during the space race and nuclear physics research during world war II | People look for meaning.
If they happen to be born in a successful country, taking pride in that country, can boost moral an efficiency at work.
Furthermore, many countries wish to create a melting pot of cultures and unite them under one nationality to avoid internal strife.
So it wont matter black, white, yellow green, American first | 302 | 900 |
ELI5: Catholic religious orders (e.g. Jesuits) | Pope Francis is the first Jesuit pope. What differentiates the Jesuits from other orders, such as the Benedictines? | Well, think of the religious orders as factions within the church, all dedicated to certain goals that are shared within the order, and compatible with the goals of the church as a whole.
The easiest way to distinguish the Jesuits from the Benedictines is that the Jesuits are an apostolic ministry...They go out in the world and build schools and hospitals, and preach to people. They're loosely organized, and mobile.
On the other hand, the Benedictines are a monastic order (monks), tied hierarchically to their various abbeys and monasteries. The Benedictines have traditionally had a lot of the more influential thinkers in the church (which may seem odd since the Jesuits are known for education), but the Jesuits are much more worldly. | 12 | 32 |
Best PhD for teaching higher education STEM courses? | Hi everyone,
I work in academia as an hourly instructor/teaching assistant in the USA. My bachelor's degree was in molecular and cellular biology but I currently teach general chemistry courses because that's where my work experience lies. I've been teaching for about two years but I would like to move on to grad school soon and I need to pick a major.
Although research is alright, I love teaching and I'm willing to settle for a lower salary than the typical professor in exchange for the opportunity to teach full-time at a higher education institute, without being required to do research. I'm wondering what would be the best PhD (or master's, I suppose) to go for with that goal in mind.
I'm currently considering getting my PhD in either Science Education or Higher Education Teaching. Alternatively, I could get a master's in STEM education, or I could bite the bullet research-wise and simply get a PhD in molecular biology or a related science field. Is one of these options better than the other, assuming I would preferably like to end up as a teaching professor? Is a teaching professor position at a university likely, or do I need to set my sights lower (perhaps a teaching position at a community college, for example)?
Thank you for taking the time to read my post and I appreciate any advice you can provide!
Edit: Thank you everyone for the input! Some very good points were made and I'm grateful for the advice. The general consensus among responses seems to be that a PhD or master's in a specific science field is the best option. I will look into that more, thank you! | You'd be more competitive with the PhD in molecular biology (or whatever specialized field) and taking as many TAships, instructing classes, and doing teaching trainings offered by your grad institution as possible. You'll want to demonstrate high investment in teaching on your CV, but you'd be more competitive at most institutions (especially R1) with a subject-specific PhD than a Science Ed one. | 48 | 54 |
ELI5: If colds aren't caused by the cold, why do people get colds in the winter? | I've been wondering | Colds don't cause the cold, but coldness can negatively impact your ability to prevent and deal with diseases. But the primary reason why people get more sick in the winter is that we stay inside more and are in close quarters with other people more, which are ideal conditions to spread disease. | 45 | 51 |
If the liver can regenerate, how do people die from liver failure? | Liver failure can happen in two ways. First, the acute damage can simply be too serious for liver cells to deal with before the person dies. Second is a more protracted process, where damages accumulate.
Suppose that the liver has taken damages from infection/drug/alcohol/etc. **Then, instead of liver cells regenerating, scar tissues can form in the liver and replace them.** Scar tissue is tougher than cushy liver tissue, so this leads to hardened liver with reduced function. (Cirrhosis) If this damage keeps piling up, the liver will eventually be overwhelmed and lead to chronic liver failure. | 1,421 | 2,370 |
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[star trek]how does Earth's education system deal with races like Klingons who reach full adulthood in under 10 years? | They reach physical maturity, but the simple fact of it is that primary education up to Federation standards takes over a decade. We know that when Worf was 13 he was still playing youth league soccer-- and he accidentally killed another player. | 84 | 111 |
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Why does it take our eyes longer to adjust from light to dark than from dark to light? | Turning off lights in a room, will take eyes a few minutes to adjust and start to make out objects. turn light on and after initial sudden flare in eyes we can see everything. | The pigment protein in the rods of our retina, rhodopsin, is responsible for our low-light vision capabilities. When it absorbs light, it photobleaches, becoming inactive, until it is recharged by the biological processes in our eyes. When we are in bright light, all of the rhodopsin is photobleached and the rods no longer function, and our vision is dominated by the cone cells (which work in bright light). So, when dark conditions occur, the rhodopsin has a chance to regenerate, but this takes time (around 30 minutes or so to fully regenerate). Thus it takes some time before our ability to see well in the dark begins to work well again.
Photopsin, the pigments that work in our cones, have a similar process but they are much less light-sensitive. However, with really bright sources of light they can photobleach too, which is why when you see something really bright, it can leave a dark spot in the place where the bright image was for awhile. All the photopsin pigments in that area have photobleached out and need time to regenerate to re-enable normal vision. | 17 | 22 |
How can photons be 'massless'? | A photon can be thought of as a disturbance in the electromagnetic field which pervades all space. It propagates through space in a similar manner to a wave moving over the sea. We wouldn't say that the sea wave has mass itself, as it's just a disturbance in the water, and yet it does nonetheless transport energy from place to place (as evidenced when waves hit something).
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ELI5: How come cats can face off with animals way bigger and deadlier than them (like bears or crocodiles) and still manage to scare them off and assert dominance? | In ecology there is a concept that animals balance trade offs when foraging. For example, for a bear is risking getting his eyes gouged out by the cat worth killing the cat or take the cat's food? Most likely not. | 29 | 53 |
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ELI5: What is "irreducible complexity" in regards to the theory of evolution? | I've read a few things but still don't think I get it.
1. What does the term originate and what does it mean?
2. Why do creationists use this as "proof" against evolution?
| One of the main ideas of evolution is that small changes add up, resulting in big adaptive changes over time. For instance, fish using fins to crawl across land to new mud puddles, fins get bigger, blablabla legs.
Irreducible complexity is saying, "Well how would a creature incrementally evolve a wing? Half a wing won't help you fly, so it never would have been selected for in the first place. And what about an eye? 'Half' an eye is completely useless, so obviously a creature born with half an eye would not be selected for by evolution."
So, its saying that things like eyes and wings are "irreducible complexity." That is, they cannot be any 'less' and still have function. The conclusion being that incremental changes, as theorized by evolution, would never result in their existence. | 21 | 24 |
ELI5: Why is the order of operations in math PEMDAS? Why not another order? | The higher-priority operations are also the higher-order operations -- i.e. you construct multiplication out of repeated addition, you construct exponentiation out of repeated multiplication. So the ordering is high-order stuff first, then lower order stuff.
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I recently read Bowling Alone and am trying to understand some of the methodology behind it: what statistical methodology is used to a find a "best predictor"? | I feel like this is an embarrassing question to ask since I have a large econometrics background. I'm familiar with various forms of regression models and causal inference, but I feel like I'm missing something obvious here.
An example from Bowling Alone: "... the best predictor of which children successfully avoided such problems was the degree to which their mothers where enmeshed in a supportive social network, lived in a socially supportive neighborhood, and attended church regularly"
What statistical technique(s) is (are) used to find the "best predictor?" | it's hard to say without more specifics about his modeling strategies. Perhaps he's just using that as a shorthand of saying "the strongest correlation coefficient" or "the largest standardized beta"? | 19 | 23 |
ELI5: If oil and grease both act as lubricants for metal on metal contact; why can't you use them interchangeably? | Typically, oil is used in higher speed, lower stress applications, where heat build-up is more of a concern than stress on the moving parts, such as the fast-moving engine cylinders. Oil serves as both a lubricant, and a coolant, by continuously circulating fresh cool oil from a reservoir, often with an oil cooler similar to the radiator for water/antifreeze. Oil has to be thin enough to be pumped and exchanged. Grease is typically thick and semi-permanent, only occasionally being changed or added, and is used in more slow moving, but occasionally high stress applications such as the moving parts of the steering system. | 175 | 106 |
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Does the human eye's depth of field change with iris dilation? | In photography there's a metric called the F-stop that describes how wide the aperture of a lens is, and the narrower the F-stop, the wider the depth of field is (meaning more of a photo will be in focus). Is the same thing true of the human eye? Is more of a person's visual field in focus in brighter light when the iris is narrow (in photography terms, "stopped down") to restrict light coming in? | Yes.
You won't notice it because your eye flexes your lens to focus on what you are looking at, but the physics still applies: when you are in bright light and your pupil constricts, you get all the benefits of a small aperture. That's why old people like me can read small print at close distances in bright light. | 15 | 21 |
Judit Polgar, Hungarian chess Grandmaster, was apparently raised by her parents as an experiment to prove that children could make exceptional achievements if trained in a specialist subject from a very early age. Where there conclusive results of this and has it been done elsewhere? | Studies are quite consistent that by far the single biggest predictor of whether someone becomes a highly skilled chess player is how much time they spend playing chess - and this is true even for kids whose parents forced them to play, so it's not just a case of people who are naturally talented choosing to play more. What's true for chess isn't necessarily true of other fields, though.
Notably, Judit has two sisters who went through the same training, and she isn't the one who seemed most talented as a young child - just the one who played most. | 27 | 52 |
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ELI5: China vs Porcelain vs Ceramic vs Earthenware | Some of these may be overlapping categories but I have no idea. | All of these are examples of Ceramics, which covers the entire set of the other items you are asking about. Ceramics are typically any sort of hard shaped material formed at least partly out of Kaolinite Clay.
The main differences between the types of ceramics are:
* Earthenware, fired at lower temperatures than other types. It is not shiny, and is permeable to water.
* Stoneware, shiny types of pottery like toilet bowls, not permeable to water.
* Porcelain, which contains a high content of kaolinite. It's heated to the highest temperature resulting in a very hard shiny non-permeable surface.
* China, which is a type of soft-paste porcelain that is composed of bone ash, feldspathic material, and kaolinite. These extra ingredients give it a high strength relative to other types of ceramics, allowing for thinner products (dishes etc...) Other than that it is prepared the same way as Porcelain, and in fact many items referred to as "China" are actually "Porcelain" instead.
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ELI5: Why do employers reject applicants on the basis that they are overqualified? | I mean wouldn't that be a good thing? | The hope when hiring someone is that you will find a dedicated worker of an appropriate skill level, who will then get the opportunity to be promoted as their skills improve over time - ideally staying with the company long term allowing them to have a better understanding of the companies practises and systems, and removing the need to be hiring as many staff (which takes time, money and effort).
To hire someone overqualified, means they are likely accepting a job below the grade they actually want but have not yet been able to find, so are much more likely to view this job as a short term stand-in and leave to a preferable job as soon as they can.
If you have a decent engineering degree, you probably won't want to last out your time as a manual laborer in a lumber yard if you could use that job to keep you adjust for the moment until something better appears, while if you have no certification beyond high school, that job in a lumber yard is a better sounding prospect as it gives you the chance to increase your sales and management skills over time and incremental promotions. | 38 | 21 |
ELI5 why do humans and most (all?) animals have symmetrical bodies? | Bilateral (humans) or radial (jellyfish) symmetry helps keep you balanced so you can move with purpose, and reduces the needed genetic complexity.
You don’t need totally separate developmental pathways for your left arm and your right arm, just a genetic copy-paste.
You’ll just swim in circles with one large fin and one short fin.
Both the vertebrates and the arthropods settled on bilateral symmetry long ago, so practically all land animals are symmetrical like that.
Radial symmetry is more popular among the jellyfish/anemone/sea urchin types in the ocean.
Asymmetric anarchy like bivalves and sponges still has a few very ancient holdouts. | 33 | 22 |
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Is there a German equivalent to Gutting’s French Philosophy in the Twentieth Century? | I’m looking for something which covers a rough narrative of German philosophy as it developed in the twentieth century. I found gutting’s book to be very engaging and helpful and was wondering if there was parallel of it for Germany.
There might not be a clear history/narrative to German philosophy in the way that Gutting is able to find in French Phil. (I don’t really know), so perhaps books covering broad movements in Germany (like Phenomenology) would be good as well.
Thanks! | Young has a three volume *German Philosophy in the Twentieth Century* which does this, although unfortunately it's three volumes so it's not quite as accessible. But you could pick a volume that looks particularly interesting to you, to start with. Or you could go with Gorner's *Twentieth Century German Philosophy*, which is much narrower in its coverage but is only the one volume. | 14 | 20 |
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