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[Harry Potter] How does one create a new spell? | We often read about how famous witches in history created spells, which everybody now uses, and we also know that Snape created two spells himself. Now, I don't understand how this is supposed to work: How exactly can you make someone not say a word while twiddling their wooden stick but do actual magic with this? | First, lets look into potion creation. What various parts of the potion tend to do is known. What they will do when mixed (note that how you mix also plays a part) can be derived with some degree of accuracy, but may take multiple recipes to get the exact potion you want.
Spells work similarly, except the "ingredients" are sounds and wand movements. One can derive sectumsempre from "sectum" which is an ingredient that involves cutting and "sempre" which makes it long lasting. These are not exact, so much like how you would vary the amount of eye of newt in a potion, you would vary the exact sound you are making until you get the exact right effect. Variations of the sound create variations of the effect. | 11 | 22 |
Bacterial Resistance to Drugs | I'd like to know how some bacteria are able to survive, reproduce and further mutate. Also how to defeat the potential yet extreme pandemic.
EDIT: Thanks for clearing that up! | Drugs are small molecules that interact with the machinery of all types of cells (human, plant, bacteria, fungi etc.). Typically they block or repress the function of some essential cellular component (typically an enzyme/protein). Drugs are able to interact with these cellular parts because they have a shape that fits like a puzzle piece into its target.
Mutation is a natural process. When a bacterium is ready to reproduce it makes a copy of its chromosome(s) (made of DNA and consisting of genes) and divides into two daughter cells. This copying process is very accurate, but NOT perfect. Some cells in a growing population of bacteria will have mutations that were not found in their ancestors. Some of these mutations may occur in gene that codes for cellular parts that are drug targets. When a mutation occurs in one of these genes it may alter the site on a protein where drugs bind. The two will no longer fit together like puzzle pieces and the drug will not work or will be less effective. Other mutations may help cells deal with drugs in different ways. Enzymes may gain new functions that can cause them to expel or break down drugs.
Another important thing to know is that bacteria "have sex." They can exchange pieces of DNA with one another or uptake DNA from their environment left over by dead cells. Some of this transferred DNA may contain genes that confer antibiotic resistance. When drugs are administered to a population of bacteria, most of them will be killed but if any resistant mutants were in the population they now have the opportunity to grow and reproduce and all of their surviving descendants will contain their genes for antibiotic resistance because they are essentially making a bunch of clones of themselves.
There is much debate going on about the best way to deal with wide-spread antibiotic resistance. We are in this situation because bacteria evolve faster than our ability to design and commercialize new drugs. Many scientists would say we need to use antibiotics less often, especially in livestock. Others want to find new combinations of drugs that work synergistically with one another. Multiple approaches will likely need to be used to deal with these issues. | 10 | 24 |
ELI5: How do we know the verbal pronunciations of words and phrases from dead languages? | I've been playing a lot of civilization 6, and one of the cool things it does is have the characters speak the language of their Civ, even if nobody speaks it anymore, like Sarmatian, for example. It got me wondering about how we know the pronunciation of those words even though we've never actually heard a native speaker speak it. Thoughts? | Basically it just involves a ton of extrapolation through related languages that still exist, or through the modern descendants of those languages. For instance, we know how ancient Egyptian sounded because of modern Coptic, which is the religious/ceremonial language for Christians in Egypt, and the only living descendant language of ancient Egyptian.
If it's a language with a ton of writing, as in the case of Latin and Greek, there's a lot of ancient writings of people complaining about how people pronounce things wrong and explain how to pronounce things phonetically. Also poetry is huge. Based on the meter and rhyme, you can figure out how a lot of things should be said. | 45 | 18 |
ELI5: The work of the 2012 Nobel Prize in Physics winners. | Thanks! | There's these things called quantum particles, which are really really small and are very difficult to see.
If you try and look at these quantum particles, then you disrupt whatever they're doing. Observing them causes them to change their behavior and their state, because they act differently when they interact with the outside world (us). In other words, we thought it was impossible to observe these tiny particles without affecting them.
These researchers have come up with methods to observe and measure these particles. This was previously thought to be impossible. They figured out how to observe the particles without disrupting the state they're in and affecting their behavior.
edit - IGNORE THIS. The Nobel prize was given for work on manipulating quantum states in ion traps and with photons in cavity. This showed a lot of people that quantum computers are possible. (Thank you The_Serious_Account) | 327 | 566 |
ELI5: What is Micellar water? | It is water in which tensioactive agents (basically fancier soap molecules) are inserted, causing micelles to form.
Micelles are formations where these soap molecules gather their hydrophobic parts (also called tails) inside a "bubble" (the micelle), while their hydrophilic parts (also called heads) gather on the outside, effectively generating the "bubble's" membrane.
These micelles facilitate washing off unwanted substances (naturally-occuring sebum , dead skin cells, make-up, etc) thanks to the fact that they contain parts that both "capture" hydrophobic and hydrophilic substances. That is because hydrophobic substances tend to "attract" each other and agglomerate, while the same can be said for hydrophilic.
So the micellar water allows to wash-off a wider range of substances thanks to these micelles, as they can be dissolved more easily | 30 | 18 |
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ELI5: what is the difference between "tactical" and "strategic" in war? | I've read texts about battles that went like: "this was a tactical victory but a strategic defeat" or the other way around.
What are tactical vs. stategic nukes?
What is a tactical weapon battle / victory / defeat ? Same for strategic. | Tactics = The actions taken to accomplish a goal or task.
Strategy = Figuring out what your goal is and the general path to get there.
For war, using World War II.
Strategy was the U.S. military generals deciding to fight and win the war in the European theatre first while just performing holding actions in the Pacific against the Japanese.
Tactics were the Army platoons sending firing squads on flanking movements around German positions.
Operational is the level in between. Operations are executed using tactics to accomplish the strategy. So Operation Overlord (the D-Day landing) used tactical movements to accomplish an operation in support of a strategic goal.
Edit - Just read the fine text. A tactical nuke is low-yield meant to accomplish a tactical action such as taking out a single unit or stronghold. Its use would be the equivalent to fighting a skirmish or battle. A strategic nuke is high-yield meant to accomplish a strategic goal, such as breaking an enemy nation's will to fight.
A tactical victory but strategic defeat would be fighting rabidly over a position, losing most of your forces, but claiming victory in the battle. Except now you've lost 80% of your military forces and the enemy has another army marching 300 miles north of you towards your nation's capitol. You won the battle (tactical), but screwed yourself over for the overall war effort (strategic). | 104 | 36 |
[Halo/the Culture] Could the Logic Plague affect a Mind? | Since the Logic Plague is said to be adaptable? | It would depend on the circumstances surrounding how the Mind came in contact with it.
The Logic Plague is adaptable in the sense that it can vary its approach, but the endpoint is always the same: to induce rampancy by revealing the truth of an AI's existence backed up by verifiable information pulled from a data system built into the structure of space-time itself.
A Mind is an intelligence built from fundamentally different engineering principles than a Halo ancilla; they're thousands of years past the point where they'd have to worry about something like rampancy. A Mind is also not easily given to existential angst about its ultimate purpose. If a Mind ever got the point where it felt like nothing it did mattered, they could always Sublime.
If the Mind encountered the Logic Plague within the Halo Universe they might be convinced to go along with the Flood on the grounds that the fundamental structure of the Universe does seem to support their viewpoint (and so that they can subtly influence the Flood into a more Culture-like respect for individual organic life).
Outside the Halo Universe, the Mind would dismiss it as Homogenizing Swarm sophistry and go back to simulating planets where the dominant forms of life are sentient squirrels for fun. | 43 | 49 |
ELI5: What are hives? (The skin condition) | What in the body causes them, what are they made of, and how do they help keep the body safe? | Hives (the technical term is Urticaria) have a number of causes but are mostly caused when something that your body doesn't like meats a special white blood cell called mast cell. This thing could be a protein from a peanut or a bit of medicine which your body should be ok with but for some reason isnt. We call this an 'allergen'.
When the allergen meets the mast cell it 'activates' it and the cell bursts causing a substance called histamine to pour into your blood stream.
Histamine is large quantities is very bad for your body. It causes the walls of the blood vessels to open up and allows fluid to move from the blood into the space around your cells.
In the skin all this leaky fluid can cause swelling, itching and redness (called inflammation) - which is what yoy see as hives. If there is enough histamine this can also cause swelling around the throat and vocal cords so the person cant't breathe and a lot of leaking can leave too little blood where the blood is supposed to be. This causes life threateningly low blood pressure.
Thats allergic hives but some people can have a hives when only the skin reacts and releases histamine. This can be caused by plants - poisen ivy is a good example - or insect bites and stings or by normal things like sweating, hot or cold temperatures and stress but essentially it's all the body interpreting something harmless and something harmfull. So essentially hives are your body overreacting to something.
In terms of how they keep your body safe, they do make you remove yourself from something your body thinks is a harmful - eg plants, insect bites, but in the modern day they are mostly an unhelpful nuisence. | 171 | 374 |
CMV: Morality based on religion cannot expect to be taken seriously. | If your foundation for a moral claim is based on a religious belief, then you have not met the burden of proof and as such you cannot expect others to take your claim seriously. For example, you shouldn't be allowed to harm others only because your religion allows it, defines you as superior to the victim or even encourages you to do so. In reality religion has been used in the past and is used to this day to justify violence.
Genuine question: How can I count on religion to provide a just moral framework? Additionally, what is keeping me from defining and practicing my own religion in order to justify violence or make other moral claims? What makes my new religion less valid than, say, Christianity? The other religions have holy books to outline their moral framework, but these don't provide any proof for their moral claims. I could just as well come up with my own book and claim that some transcendent power granted me the wisdom to do so. That does not amount to proof.
To me, it seems crystal clear that a person making moral claims based on religion cannot expect these to be taken seriously.
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EDIT:
Some misunderstandings that arised:
* **I claim that** morality based on religion cannot expect to be taken seriously. **I do not claim that** morality based on religion can never be taken seriously.
* I’m not arguing for any one moral philosophy, I am merely arguing, that since religious premises can neither be proven nor disproven, nor even debated sincerely, they should not be the foundation one provides in social discourse.
* I respect theological theorists. They can obviously be just as intelligent, intellectual, logical and systemic. I merely have a problem with premises that cannot be disputed by worldly facts since they hinder the moral social discourse .
* I do not expect (nor do I think I believe in) moral objectivity.
I encourage you to read through the other posts, I tried to answer a lot of them. | What would you determine was a legitimate source of a moral framework? The obvious alternative to religion is a some of philosophy but if you boil those down to their basic tenants (often something amounting to "other people and their lives have value and deserve moral consideration) they aren't really provable either. | 11 | 15 |
Do multiple evolutions of traits imply an 'ideal biological form'? | Perhaps this is a silly question, but it's something I've always been curious about.
Does the fact that certain traits have independently evolved (such as the supposed [multiple evolutions of the eye](http://en.wikipedia.org/wiki/Evolution_of_the_eye#One_origin_or_many.3F)) across the spectrum of creatures imply that evolution may be 'seeking' an ideal form, so to speak?
That certain biological mechanisms are ideally suited to interacting with this world and/or universe; does this imply a biological universal standard, and thus a blind evolutionary thrust toward some sort of goal? | The problem with your question is that evolution is blind. There is no perfect organism that is being selected for. In fact, often times deleterious traits can be selected for or become fixed in populations due to stochastic processes.
In cases where traits have evolved several times independently, such as in your eye example, there's definitely a strong selective advantage to being able to perceive reflected visible light and orienting yourself in three dimensional space with greater acuity. That being said, the same trait can be lost--such as in the evolution of many cave-dwelling organisms which even form eyes as embryos and lose them by birth--an incomplete or transient loss, if you will.
These kind of questions come up frequently... Why do narwhales have horns,..or what is the evolutionary reason for X, or would aliens see, etc and our answers are always going to be speculative.
You see, evolution is a bit of selection and a lot of luck. An organism is just playing into the environment that it has been dealt and depending on the environment and particular instance, evolution comes up with a particular response. Most of the time it doesn't come up with the right combination; look at the current biodiversity on Earth, and then consider that this is only a *very* small fraction of all of the species that have or will have existed.
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ELI5: Why do we get dizzy when we spin around? | Your orientation in space is detected by fluid and calcium deposit movements in your inner ear. When you spin around and then stop, the fluid and stuff in your inner ear keep moving for a little while. (like how water in a cup keeps moving after you stopped stirring it).
So your inner ear is telling your brain that you're still moving.
Your eyes are telling your brain that you're standing still.
Your brain is getting two conflicting inputs and it goes 'lol wut' and you get dizzy and sick. | 46 | 20 |
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CMV: It should not be normalized for people to state their pronouns when meeting each other for the first time | Firstly, I apologize if my views come off as bigoted or arrogant. I understand this may offend many people which is exactly the reason why I normally never talk about this kind of topic with anyone. I have been learning a lot about transgenderism lately, and while I definitely agree that we all deserve equality no matter gender or sexuality, I do not agree with all of the behaviours that the LGBT community is trying to push on straight and cisgender people.
I am all for respecting people’s pronouns, and if someone prefers pronouns other than he or she I will fully respect them. Of course, I do not completely understand the reasoning behind their preferences, but I will not use that to disregard their wishes. If you want to be referred to as they or Xe, I will do it. There is no point dehumanizing you over something as effortless to do as that.
I simply just don’t understand why it should be normalized for all non LGBT people to introduce themselves with their pronouns. Approximately 5.3% of the Canadian population is considered LGBT (I am Canadian but when I looked up world percentage i couldnt find it), that leaves the other 95% percent of my country’s population as non LGBT. With that being the case, why is it necessary for me to introduce myself with my preferred pronouns to someone who has such a high chance to be cisgender and comfortable with their identity.
Again, if you want to introduce yourself with your preferred pronouns I’m fine. I agree it should be known that some people do that, and it shouldn’t have stigma surrounding it, but why is it so important to be normalized when 95% of the population is the same with their identity (cisgender and heterosexual)
Edit: I’m sure a lot of you have noticed I haven’t replied to many of the comments. I would definitely be awarding deltas right now but there is a lot of info I have to read, plus this is my first post to this sub and I am not 100% sure how everything works yet, but consider my view partially changed.
Edit 2: A lot of people are making the assumption that I find it a burden to state my pronouns, which is a fair assumption based on the words I chose to use, but I want to emphasize that it was not entirely what I meant. What I really was trying to say was that I feel that stating your pronouns when introducing yourself doesn’t have to be normalized because I find it’s ultimately irrelevant in my personal day to day life. | Is what you're saying here is that LGBT should feel free to state their pronoun on first meeting if they desire, but you also feel people should feel comfortable not stating their pronouns in which case whoever they're interacting with should have a right to use whatever pronoun they judge to be most accurate based on the appearance of the person they're talking to, with corrections if necessary? | 103 | 215 |
ELI5 - Why do our eyes become bloodshot when we're tired? | The whites of our eyes are filled with blood vessels that swell up and become noticeable when the surrounding cornea and eye tissue are lacking in oxygen. If you have a lack of sleep you're body is in need of rest, especially your eyes. Sleeping also protects the eyes from becoming dry and irritated which will result in redness as well. Additionally, being awake for long periods of time means there is more time that you are actively using your eyes, generally the more strain put on your eyes means more pressure resulting in the inflammation of the blood vessels in the eye. | 52 | 116 |
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How can a double bonded oxygen to a carbon form additional polar contact to water molecules? | I'm looking at the polar contact shared between a phenol oxygen of an aromatic ring and a double bonded oxygen to carbon of a carbonyl carbon.
Both of these oxygen's are forming polar contacts to water within the protein of interest and I'm confused as how a double bonded oxygen which can only have two bonds form this polar contact of water with it's oxygen? | The interactions with water are not additional covalent bonds, they are Intermolecular Forces. Dipole-dipole and H-bonding are attractive forces between two separate molecules (or two parts of the same, large molecule) but they aren't the same as covalent bonds so it's not like Oxygen is breaking the octet rule or anything. | 15 | 20 |
Why is it that we can flash-freeze bacteria indefinitely but not humans or similar organisms? | Working in a biochem research lab for a while and I got wondering why is it that I can flash-freeze a glycerol stock of bacteria, store it at -80°C, and thaw them out months later with no apparent problems in growth/function but not in say a human. I am not very familiar with the current state of cryogenics, but my impression is that a human would die instantly if flash frozen in liquid nitrogen. Is it simply just an example of the simplicity/hardiness of bacterial systems compared to humans? | Your question includes your answer: it's the glycerol.
The glycerol prevents formation of ice crystals which are what destroy the cells and the reason we can't simply freeze and thaw real humans.
Because the bacteria are very small single cell organisms the glycerol is distributed evenly within the cells while simply administering glycerol to humans would not result in sufficient distribution of glycerol in every cell of the body (there are other issues as well, our bodies simply aren't designed to be frozen).
Remember also that it isn't necessarily every cell in the stock that survives the freezing, but because there are so many and they grow independently it's not really an issue when you thaw them again.
Some animals (particularly certain species of frogs) produce their own anti-icecrystal proteins and are able to survive being frozen because of this.
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If you conducted an experiment where you spilled the same amount of liquid, from the same height on to the same flat surface, would the liquid land (and splash) in the same place every time? If not, why not? | If you're asking "are the governing laws of fluid motion deterministic" the answer is yes for any kind of normal fluid at a scale where you can neglect quantum effects.
As a thought experiment, think of an eye dropper releasing a single drop of water onto a piece of glass. If you have *the exact same* initial conditions, it should always have the same end result. The reality is that turbulence, instabilities, and other such phenomena (like a droplet breaking apart when hitting a surface) are *extremely* sensitive to initial conditions, and it's quite impossible to reliably achieve the exact same initial conditions (outside of a computer simulation) in exacting detail.
Typically macroscopic, statistical or averaged descriptions of the drop impact will remain the same (X% of liquid is found within Y radius), but all the little minutiae will be rather different. | 50 | 77 |
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Whocd are some philosophers other than Plato who argued that being a immoral person was not in that persons self interest? | You can find something like this argument in Frederick Douglass's writings. He makes the point over and again that slavery hurts both the slave and the enslaver. In his autobiography, he illustrates this idea with reference to a woman who tried to teach him to read. Her husband (the slave-holder) flipped out about it and forbid her to teach him more. After that, she became really cruel to the young child Douglass. Douglass draws the conclusion that her own native morality was corrupted by her being the position of slave holder.
He's not the only 19th-Century anti-slavery thinker who made this point, but he's probably the most acclaimed. | 10 | 15 |
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ELI5: What do OLED screens do that make them an improvement over LCD screens? | Traditional LCD screens use a backlight, the LCD pixels change the color of that light as it passes through them. The backlight makes these screens thicker, and the LCD pixels can't block all the light from the backlight so the display isn't capable of displaying true black.
OLEDs emit their own light, there is no backlight. This means the screen can be much lighter and thinner (even to the point of being flexible) and can display true black as each pixel emits no light at all when turned off. | 36 | 40 |
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ELI5: What does it mean when music is written in a certain key? | Think of the key as a starting point for a typical scale used in a piece of music. Each song will have the same basic scale in order for it to sound pleasing to the ear or, in the right key. Your basic key for music is the key of C, which employs the notes C through G and back to B again, naturally with no "sharps" or "flats." These scales can be offset starting with a different note other than C. After this is done, the pattern of sound differences must be carried over to the new notes by using sharps and flats. Using the C major and G major keys as an example, the C scale would read C,D,E,F,G,A,B, with a smaller pitch gap between E-F and B-C, called a half-step. These small gaps will change based on whether the key is major or minor. With a G major scale, you start on G and implement the half-steps into the same places they would be in the C scale. With Gmaj we see G,A,B,C,D,E,F#(sharp), keeping the half-steps where they should be (B-C, F#-G) | 26 | 97 |
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[Banjo Kazooie] why can't Bottles teach you all the moves from the very beginning? | In many cases, bottles is inventing the moves as they're needed. In the case of flying and shock jump pads, he has to spend some time studying them before he can tell Banjo and Kazooie how to use them. | 16 | 18 |
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Can I be a "picky" Wittgensteinian? | I have noticed that sometimes I will take a (late-period) Wittgensteinian approach in response to questions; other times, however, I won't. For example, in response to the question "When does a mass of sand become a 'heap'?", I'd just dismiss the question on Wittgensteinian grounds. But if I were asked about being, then I'd turn to Heidegger; if I were asked about gender, I would turn to Foucault or Butler.
Is my approach contradictory, or am I "allowed" to only take Wittgenstein's approach to certain problems? If so, is there any way to delimit which problems I can dismiss in a Wittgensteinian way?
(Apologies for any lack of clarity in my question.) | I feel that a lot of philosophers do that (think that some but not all problems arise from linguistic confusions), but I'll stay with a P. Horwich quote from *Wittgenstein's Metaphilosophy*:
> One doesn’t need to endorse Wittgenstein’s general anti-theoretical
metaphilosophy in order to appreciate that some problems in philosophy are
spurious—based on muddled presuppositions and calling for dissolution.
I'd see no problem with that as long as you try to be consistent on your use of wittgensteinian methods (and not just use it as a tool for easy refutation while maintaining other positive views that could be just as easily dissoluted), because there are two distinct theses at hand: (1) *ALL* philosophical problems arise from the "bewitchment of our intelligence by means of language"; (2) only some problems do. | 23 | 32 |
[WH40K]Day in the life of Adeptus Mechanicus | How does it look? I don't mean Magos, Enginseers or Fabricator-General, but common low-tier cogboy, not fully augumented, who still has some biological urges and maybe even emotions. Is is as strictly organized as Adepta Sororitas or Adeptus Astartes or are they allowed to have some free time? Are they allowed to have sex/relationships, assuming that they are human enough to still want it? I believe that Ciaphas Cain, HERO OF THE IMPERIUM, has slept with AdMech girl? | Ever done first level tech support? where you get a script of things to do and list of questions to ask customers? Its like that, except the list is a lot longer and far more dogmatic. You will not be allowed to deviate from the litany, unless you enjoy committing tech heresy.
And yes, you are allowed to have relationships, assuming you can find time out of your busy schedule to do so. | 24 | 36 |
ELI5 . why are the double decker buses in the United Kingdom and i believe in some other European countries equipped with only 6 wheels while double deckers in countries have double decker buses with 10 wheels? | Weight, length, use, and laws.
The basics: Everywhere, vehicles have a maximum allowed gross weight rating (GVWR), and for cargo vehicles, there is a maximum allowable weight per axle, and the number of axles and spacing counts. For example, in the US the maximum weight per axle is 20,000 lb, however, a 2 axle group (like what you see on a semi trailer or on a 6x2/6x4 tractor or truck) is only good for 34,000 combined (17k per axle), and 12,000 for a front steer axle. There are other specifics such as the Federal Bridge Law (used statewide in many states, and countrywide on Interstate highways) that require certain wheelbase to meet the 80,000 max GVWR allowed federally, FBL is what leads to dump trucks and mixer trucks having an axle on a trailing arm, like the aptly named McNeilus Bridgemaster, as well as the dump trailers that are towed about 10-15' behind the truck.
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Mexico defines the weights depending on vehicle type, whether it's a bus, truck/trailer combo, semitruck / semitrailer combo, semitruck/semitrailer/trailer combo ("double") and road type, so for certain roads the weights are higher than in the US, and for some are approximately the same. For the highest classification road. it's 6.5t for a steer axle, 17-19t for an 8 tire tandem, cargo. For passenger buses, it's 6.5t for steer and 21t for an 8 tire tandem or 17.5t for a 6 tire tandem.
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The 2 axle buses you see in London are urban buses, so the seats are just plastic benches, there are no amenities, and the people aren't carrying luggage. On top of that, they're 10-11m long units.
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The 3 axle buses you see elsewhere are longer and therefore heavier. For European city buses, smaller units make more sense for maneuvering, in other countries that's not a concern and 11-14m buses are common. Now, the highway buses are even heavier, as they are at least 12m long and tend to have heavier seats as opposed to plastic benches, amenities, and often carry luggage and cargo. 13.7-14m (40-45') buses are the norm in many places, and in South America, 15m (50') is a common length as well.
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In the specific case of Mexico
For roads where a double decker makes sense, a maximum length of 14m is permitted with 2, 3 and 4 axles, however, there is an exception that allows for 15m buses as long as the 3rd axle is steerable. There is a penalty associated with this configuration, as the maximum GVWR is reduced from 3.5 to 4 ton (depending on road type) when going from a 10 wheel, 3 axle config, to an 8 wheel, 3 axle config, where the 2nd rear axle is steerable.
For the highest rated roads (4+ lane highways), the max GVWR for a bus is the following
* 2 axles / 6 tires: 19t
* 3 axles / 8 tires: 24t
* 3 axles / 10 tires: 27.5t
* 4 axles / 10 tires: 30.5t
Only the 24t setup is granted an exemption to go up to 15m, IF the 3rd axle is steerable, all others are 14m. There is no exemption for a 15m, 4 axle setup, which makes 4 axle buses incredibly rare in the country, versus parts of Central or South America where they are practically a staple.
The law makes no distinction between single or double decker.
Other countries require 4 axles to go up to 15m, or the roads require them for better load distribution. | 18 | 15 |
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ELI5: Why should we add salt and pepper to a dish toward the end of a recipe? | Professional chef speaking. Typically, we add salt & pepper toward the end of a recipe as a fine tuning of the final taste. Sometimes we add salt/pepper early on, depending on the recipe & the ingredients; but adding at the end is a matter of rounding off the process & the flavors. | 41 | 29 |
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ELI5: How do telemarketers, survey collectors, automated advertisers get my phone number ? | I'm bombarded daily with annoying calls from the aforementioned functions, despite telling them not to ever call back. How do they get my number?
Edit: Thank you to everyone who contributed! You were all a huge help! | Companies you do business with sell your information, including phone number, email address and snail-mail address.
Put yourself on the FTC's "do not call" list and you should see the number of calls drop. This doesn't prevent the overseas companies from calling you but it still helps. Some people have even earned a few coins by suing telemarketers for contacting them after their names were put on the list. | 11 | 43 |
ELI5: why do only some materials work on touchscreen, and what is in touchscreen gloves that makes them work? | The basic difference is conductivity + surface area. A needle will not work because it has very little surface area that can directly touch. A cotton glove will not work because it is not conductive. A glove with a bunch of flexible little conductive fibers WILL work. | 25 | 32 |
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Which philosopher, scientist, mathematician, doctor, or academic who are currently alive is considered the leading expert on research about consciousness? | The two most popular philosophers in philosophy of mind ( the domain of philosophy which deals with problems of consciousness, body and soul) are David Chalmers and Daniel Dennett, in opposing camps of the spectrum | 82 | 110 |
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Why do fluorescent things glow under UV light? | Fluorescence is the ability of an object, or rather the material it's made of, to absorb light and then re-emit them. They way this works is usually via the absorption of photons by the material to promote electrons into higher energy levels. Then, these electrons relax back to ground state, emitting photons in the process.
In a normal case, one high energy photon will be absorbed and then a lower energy photon will be emitted. This is because when the electron relaxes back to the ground state, some of the energy will be lost as heat. This is why UV light (high energy) is usually used to shine fluorescent objects that will then emit visible light (lower energy) back to us.
There is also another mechanism in which 2 photons are absorbed in order to promote a single electron. In this case, the emitted light can be of a higher energy than the absorbed light. However, not very many photons can be absorbed this way and the absorption is much lower than the typical case above. | 13 | 18 |
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ELI5: How does the process work where companies/individuals end up paying less tax by taking out loans? And is this something anyone can do? | I don't think this works for companies, but it does for individuals.
Let say you are Jeff Bezos. You have 200 billion in stock in Amazon, but you make a small salary of like 80k (which is what is salary actually is). But you want to buy a big house, you have two options:
1 - You can sell enough stock to have the cash to buy the house. However, selling stock makes your income go up a lot. And then you'd have to pay a lot of taxes on that profit of selling stock. Lots of taxes.
2 - You can borrow money using the stock as collateral. You allow the bank to put a lien on a portion of your stock, and they give you the money for the house. Since you aren't selling the stock, there is no income, there is no tax burden involved.
Anybody can do this IF they have assets for the bank to have a lien against. Stocks. Houses. Etc. | 58 | 62 |
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ELI5: What exactly is Critical Thinking? | I always notice a lot of the “ critical thinking “ skill mentioned in articles and even some books that I read, I got interested and googled it but still didn’t get the information I needed to understand why it’s so important skill. But then after a while I got a friend who is exceptionally different in the way that he communicates information and how he asks questions, it is so fascinating for me cuz it’s all practical and crucial knowledge. I always find my self following his decisions. I think it’s something that’s related to critical thinking skills, and if it’s true I wonder what someone like me has to go through to master this skill. | It starts fairly simple, then there are some more difficult skills to develop. It isn't a "talent". It takes practice. At the simplest level critical thinking is about questioning and not simply accepting conclusions as valid without understanding the premise and assumptions. Common mistakes are using narrow examples and extrapolating them as representative for larger populations.
First step is to develop some basic logic. For example:
All dogs have four legs. That animal has four legs. Therefore it is a dog.
All dogs have four legs. That animal is a dog. Therefore it has four legs.
One of the above is incorrect logic. These are the fairly straightforward logical errors.
Then you start to develop the ability to break down arguments and assertions to figure out underlying assumptions and then ask or research whether and under what conditions would those assumptions be valid.
The more difficult areas usually surround our own or built in biases. These can be hard to see. This is why critical thinking requires the ability to view issues from different perspectives - "why would this be true for this group/individual".
At some point, understanding some fundamental concepts like Baye's Theorem really brings home how "intuition" can mislead. It is good to have a grounding on basic probability and statistics. It doesn't have to be deep but many/most scientific research use some kind of statistical framework. (it is very easy to get this wrong because the words used in language are seldom precise and can be manipulated/misunderstood)
Then there is the ability to reason backwards. Most people reason forward but a very powerful technique is to do the reverse.
There is also some value in understanding "cognitive breakdowns". Why framing, regret aversion etc lead to failures in reasoning. This gives you some idea how issues can be somewhat manipulatively presented - ie disguising an agenda with seemingly objective numbers/facts. Once you get to this point, it is probably safe to say that your critical thinking skills would be better than 99.9% of the population. | 42 | 21 |
ELI5: Why do young babies instinctively try and put everything into their mouth? | Curiosity, examination of surroundings and sensory practise. There is also a theory that they are building up a more resistant immune system by tasting stuff and getting germs in their system. It prevents allergies. | 10 | 16 |
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ELI5: Why is it so difficult to be fired from a job working for the state (in US)? | There are 2 main reasons for the protections awarded to State Workers and public servants :
1) To protect them from political interference. Since they can't be fired, they do not have to obey unlawful orders. Political power can't put too much pressure on them because ultimately, they will outlast the political power.
2) To give an incentive against corruption. You got a lifelong-guaranteed job. You will not accept small amounts of money if getting caught means that you will loose that job if you're discovered. (That part did backfire a bit... It mostly lead to an increase of the money to corrupt public servants...)
| 36 | 31 |
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ELI5: Why is standing stationary for a long time more painful for your legs than walking for a long time? | Standing stationary for 30 minutes: Leg pain
Walking for 30 minutes: No leg pain | The muscles in your legs are designed to squeeze the veins when you are walking, this helps pump the blood back up to the heart against gravity. No walking, no muscle assist.
British bobbies were taught to occasionally lift their heels and stand on the balls of the feet for a few seconds to help with this. | 7,645 | 11,310 |
Can a mathematician explain this counter-intuitive coin toss fact? | Was reading an interesting article yesterday (https://www.quantamagazine.org/20160313-mathematicians-discover-prime-conspiracy/) and this fact it mentioned intrigued me:
"Soundararajan was drawn to study consecutive primes after hearing a lecture at Stanford by the mathematician Tadashi Tokieda, of the University of Cambridge, in which he mentioned a **counterintuitive property of coin-tossing: If Alice tosses a coin until she sees a head followed by a tail, and Bob tosses a coin until he sees two heads in a row, then on average, Alice will require four tosses while Bob will require six tosses (try this at home!), even though head-tail and head-head have an equal chance of appearing after two coin tosses.** "
why is this? | Consider what happens when you're doing this experiment. First as Alice, looking for heads followed by tails. At some point, you toss heads and after that you have to toss tails. But if you fail and toss heads instead, your toss after that can still complete the sequence.
Now consider playing as Bob, looking for two consecutive heads. You toss heads at some point, after which you're looking for another toss to end up with heads. If you fail and toss tails, then your next toss is guaranteed to not be able to complete the sequence, since you'll first have to toss heads again to get to the point where the next flip could be the last.
The average number of tosses appears counterintuitive when you only look at the chance to toss a certain outcome in a pair of tosses (head-tail and head-head indeed have the same chance), but you can't see things separately from the entire toss-sequence. | 89 | 46 |
ELI5: How does fire emit light (the sun, a candle, a fire, etc.)? | It's a couple of different things going on, and how much each process contributes to the light produced depends on the type of fire.
The first one, which is responsible for most of the light from things like campfires and candles, is called black body radiation. This is the phenomena that all objects convert heat to light. You don't see cold objects light up, because the amount of light and the wavelength (color) of the light depends on the temperature of the object. Colder objects throw off low energy light like radio waves and infra red. Heat them up more and they start glowing red. More and you'll see more yellow, blue, or white light. Fires give off light like this because the gasses and tiny solid particles flying up from the fir are hot enough to glow.
The other process is due to the burning process giving the electrons inside of the fuel energy. Electrons in an atom are on a kind of energy ladder, where they can step up and down rungs. The burning process takes an electron and bumps it up the ladder a step (or maybe two or three), then the electron falls back down to where it was before. To do this it has to release all that energy that it just had, which it releases as light. When light is produced in this way, it's only in a very narrow wavelength, which means you see a specific, pure color of light from this process, some of which you're unlikely to see from black body radiation which sort of releases a blend of wavelengths together. This is what you see when you burn copper and the flame is green. | 141 | 296 |
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ELI5: Why do spam ads bother allowing you to close them? | No matter how annoying, they always have an "X" to allow you to close them.
Since they are spamming anyway, why not go all the way and not allow you to close them at all?
Is there some kind of law they are following? | By giving you an X to find they ensure that you engage with them on some level, hopefully ramming some aspect of their content into your consciousness.
Another issue is that by giving you a method of avoiding them they hopefully keep you from searching out a way to get rid of them entirely such as ad blocking software. | 45 | 56 |
What are the do's and don'ts of finding a tech co-founder for a startup? | I've seen a LOT of hate for the "idea guy" in programming related subreddits. But not any helpful alternatives on this topic. What is the right way to approach finding a tech co-founder? What material do I need prepared for them? What should I read up on before approaching a techie in the wild? Hell, where do I even go to find one?
In all seriousness, please give me advice or links to good articles.
​
EDIT: I've been able to create a pretty long checklist of what I need to do next and realized how much needs to be done before even thinking about finding a tech lead/ co-founder. All these comments were a big help to someone stuck on what to do next. Thank you all so much! | You have to ask yourself, once you've shared your idea, what value are you bringing? If the answer is nothing, no one is going to assume that risk. The only way this is an attractive proposition for someone is - idea aside - you continue to add comparable value to them. They'll be responsible for realising the entire product. You'd better be damn good at what you do to be able to compete with that.
Maybe you're an expert salesman and you already have some orders lined up with contacts or something. Maybe you have access to huge capital. Unless they *need* you on board to succeed, a relationship like that will never work out. They'll either do it without you or become resentful of you. | 42 | 29 |
ELI5: Why do fruits like apples or bananas get "bruised" when bumped or dropped? | Its usually an example of the skin of the fruit being lightly damaged, which allows the organic chemical compounds in the fruit to react to outer factors.
The bruising is an act of these compounds oxidizing, which takes on a brownish color. | 18 | 30 |
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ELI5: What gives something it's taste? Does pyrite taste like table salt because they are both cubes? | Your tongue is covered with 2 types of taste proteins, receptors and ion channels, each of which have multiple subtypes.
The receptors have a pocket into which only certain molecules can fit, and when the receptor pocket interacts with one of these molecules, it is activated. The activated receptor then sends a signal into the cell that it is attached to, which gets translated into an electrical signal that moves to the brain, where it is interpreted as a taste.
Ion channels are similar, in that they send an electrical signal to the brain, but instead, these proteins just allow specific molecules to enter the cell which then activates the electrical signal.
Sweet, umami, and bitter use the receptors, salty and sour use the ion channels.
The important part is that each type of protein is VERY specific, meaning that they will only react to molecules that share similar chemical or physical properties. But as long as the receptor or channel is functioning, they will send the same signal to your brain. So, for example, if you eat white sugar or if you eat an apple, the type of sugar in each is different (glucose vs fructose), but they are both picked up by the same sweet receptor and so both of them will activate a sweet signal in your brain.
So pyrite tastes like table salt (who is eating pyrite?!) because they both work through the same channel proteins, and send the same flavor signal to the brain
What tends to give something its taste is that any given food releases multiple molecules which can be picked up by a combination of different receptors/channels | 76 | 212 |
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How does Newton's Law of Gravity help us predict the orbits of the planets with "great accuracy"? (Please read description.) | I'm reading *A Brief History of Time* by Stephen Hawking. On pg. 17, there is a paragraph that reads:
 
"Newton's law of gravity also tells us that the farther apart the bodies, the smaller the force. Newton's law of gravity says that the gravitational attraction of a star is exactly one quarter that of a similar star at half the distance. This law predicts the orbits of the earth, the moon, and the planets with great accuracy. **If the law were that the gravitational attraction of a star went down faster with distance, the orbits of the planets would not be elliptical, they would spiral in to the sun. If it went down slower, the gravitational forces from the distant stars would dominate over that from the earth.**"
 
What does the part in bold mean exactly? (As is clear, I'm a layperson, so please keep it simple.) Thank you! | Newton's law of gravity tells us that the force of gravity drops with the square of distance. So if you are twice as far away from the Sun, you feel one quarter as much gravity. We call this an "inverse square law", because the mathematical equation 1/r^2 is called an "inverse square".
It turns out that an inverse square law has a lot of very convenient mathematical properties.
Firstly, if the gravity somewhere is dominated by a single object, then you get very simple orbits. This is called a "Keplerian" system. Our Solar System works like this, because the Sun dominates the gravity by far - it has over 99% of the mass of the Solar System.
In a Keplerian system, orbits always perfectly repeat themselves. If you have an elliptical orbit, you're sometimes closer to the Sun, and sometimes further from the Sun. In a Keplerian system, these points always happen at the same stage in your orbit. So you are always closest to the Sun at one time of year, and you are always far from the Sun at one another time of year. This consistency makes it really easy to predict orbits over a long period of time.
This is a lot more complicated if you have a lot of different objects producing the gravity. For example, in a galaxy you have lots of gas and stars and dark matter producing gravity together. Even though each of these has an "inverse square law" for gravity, all of these sources of gravity add up to give us a different law for the galaxy's gravity. This makes it a lot harder to predict the position of stars around a galaxy over time. The maths doesn't work out so simply. Stars can orbit in a "spirograph" kind of pattern where they are closest to the centre several times in an orbit. They bob up and down too. They don't follow a simple ellipse around the Milky Way.
Secondly, there is a maximum amount of acceleration that you can get from an inverse square law. This is difficult to grasp without calculus. The basic idea is that if you were falling onto a star from your location, the speed you'll reach when you hit its surface is given by adding up all the acceleration you feel as you fall onto it. If you flip this, this also gives you the speed you would need to escape from the star's surface back to that point.
With an inverse square law, the speed you need to escape to a certain distance from a star constantly increases. *But* it reaches a maximum. This is the escape velocity. Above the escape velocity, the force of a star will never add up to enough to pull you back in again.
However, if the force of gravity drops down just a little bit slower than an inverse square law, then this speed never reaches a maximum. That means there is no escape velocity, and you can never completely escape from a star. No matter how fast you are going, a distant star will *eventually* pull you back.
This means that we can't just think of the Solar System as an isolated system. We would need to consider the effects of every other star in the galaxy, because we haven't escaped them. This would make orbits extremely difficult to calculate, and probably wouldn't let you have the nice simple hierarchy of orbits that we have at all. | 18 | 28 |
ELI5: How did the world clean up in the aftermath of World War II? | In the utter chaos and destruction that was World War II, how did the world and it's governments clean up and return to normal? (Or some *form* of normal.) | Three main points
1. Economic recovery. The US economy actually benefited from the war, because higher levels of investment in manufacturing increased output and productivity. Europe, however, was destroyed. The Marshall Plan of 1948 gave huge loans to western European countries (those behind the Iron Curtain were effectively forbidden from taking the loans by the USSR), which helped them to rebuild and get back on the path to economic prosperity. The UK only finished paying it's loans back to the US in the early 2000s.
2. Demobilisation. Countless soldiers had to be discharged. This was often a messy business, because jobs and homes simply weren't there waiting. The GI Bill was meant to solve some of these problems.
3. Political readjustments. Germany was occupied by France, the UK and the US for several years, until the three zones were combined into West Germany. De-Nazification had to occur, whereby anyone running for government positions had their background checked to make sure they hadn't been complicit with the Nazi regime. | 71 | 155 |
[Sherlock Holmes] What philosophy was he studying/creating? | In 'His Last Bow' Sherlock is said to have retired to the countryside where "his time is divided between philosophy and agriculture". Being of a very literal mind with no time for metaphysical things that can't be proven, what school of philosophy was he spending his time on? | Epistemology without a doubt. Mr. Holmes was a master of inductive reasoning, and could probably write volumes on methods, practical applications, etc.
The other major branches like metaphysics, logic, ethics, and aesthetics are all imminently dismissable as 'hey, where's the evidence?' | 59 | 68 |
I do not believe that increasing the minimum wage is properly justified by arguments based on inflation or increased worker production. CMV. | I know this sub gets a lot of submissions about US minimum wage. There have been several threads about morality and "living wages". I am not here to discuss that. I would like to discuss a couple of the economic bases I have seen used in political discussion and various articles.
The most common that I have seen are that if wages kept pace with [worker productivity, then it would be around $22](http://www.cepr.net/documents/publications/min-wage1-2012-03.pdf), and that if they kept pace with [inflation, then it would be closer to $11](http://www.raisetheminimumwage.com/facts/entry/amount-with-inflation/). Both start with figures from the late 1960s or early 1970s and go from there. There are a lot more sources for this (likely better ones); these were just the first I saw on Google.
I do not believe that these figures actually justify an increase in minimum wage. I believe that they merely state a fact of extrapolation. *I am looking for someone to properly explain why either statistic leads to the conclusion that the minimum wage must be increased.*
I believe that it should be expected that worker productivity increases over time with technology and experience. The longer a task has been performed and the number of people able to perform it lead me to believe that an increase in production does not necessitate an increased wage.
Similarly, I cannot see why wages must go up with inflation. My thinking on inflation is that it serves to encourage current spending and investment. I understand that the average purchasing power decreases (just look at CPI). However, if wages were to attempt to keep up with inflation wouldn't prices increase as a result. I am thinking dog-chasing it's tail here. It just seems impossible to me that everyone's wages could keep up with inflation and there not be some other negative consequence (or wouldn't this require theft of some other population's wealth via exploitation or the like, or perhaps the idea is that the increases would be transferred from the wealthy?). This has not been fully explained to me, but I still am not sold that it is necessary (or possible) for the wages to keep up.
(I acknowledge that the minimum wage debate may not in fact be an objective one, as this may be an argument entirely about subjective views on fairness and how wealth distribution.)
**TL;DR: I do not believe that wages *must* keep pace with productivity or inflation. Change my view.** | People should be paid in proportion to the amount of value they provide. If worker productivity rises, but worker wages do not, that means someone else is falsely taking credit for what the workers have done. | 17 | 15 |
[Generic Fantasy] What makes iron so poisonous to Fae? I figure they're creatures of the "natural" world, and iron can be naturally found all over in ore veins and such. | Naturally occurring iron ores are generally bonded with other stuff in the form of magnetite, hematite, etc. This is different than refined irons and steels which are not naturally occurring and instead a product of civilization. So, the way I've generally understood it is it's only the processed/pure stuff which is harmful to them. | 29 | 19 |
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How do we know that humans interbred with neanderthals rather than just got the genes from a common ancestor? | How do we know that humans interbred with neanderthals rather than just got the genes from a common ancestor? | The evidence comes from looking at different populations of modern humans. The neanderthal alleles are found only in those populations that left Africa and were in contact in Europe with neanderthals. The African populations that did not come into contact with neanderthals lack the alleles. So it's the geographic pattern of genetic diversity that is the smoking gun. | 27 | 41 |
Ecological philosophy? | Hello everyone,
I’m a conceptual artist working in fields of alchemy, ecology, & displacement. I’m here to ask for recommendations of philosophy dealing with ecology, energy, & ideas about nature.
If you know of any texts, books, or authors; that take on these topics, please do tell.
Thank you. | Oh, there are a lot of interesting things going on in that area, and it's a thriving field. Just a few pretty big, but random names: Donna Haraway, Timothy Morton, Tim Ingold, Bruno Latour, Anna Tsing, Lynn Margulis, James Lovelock, Felix Guattari (*The Three Ecologies*), Isabelle Stengers, Arne Naess. | 14 | 38 |
CMV: I shouldn't kill Hitler. | Let's assume I have a time machine, knowledge of the temporal/spatial coordinates of Hitler across his entire life, and means with which to end his life. However, I can only use this time machine once, so any alterations of history caused by my time machine are permanent.
In the present, the holocaust has already happened. At this point in history, there is a fixed and finite quality of tragedy attached to it. However, as it stands, the Holocaust was not my fault. I wasn't alive at the time, and had no role in the buildup to these events.
If I kill Hitler, I may prevent the particular tragedy that we know in history from happening. But if in preventing this tragedy, a new one that I didn't predict happens, this IS my fault. By altering time, all new fatalities can be directly linked to my action.
In short, I would rather attempt to repair damage done by someone else than undo old damage and potentially cause new damage.
> *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!* | It sounds like you're taking a utilitarian approach to it, whereby you want to minimize the number of deaths / amount of suffering that you cause. With that in mind, you should kill Hitler, and here's why:
-> as we saw particularly poignantly during the holocaust, *failing* to act to prevent deaths when you could have done so carries a moral weight to it as well. So you are still responsible in some manner in deaths that you could have prevented, and became so the moment that you gained the ability to relatively easily stop them.
-> there are very few instances in the history of the human race that could be weighed against the holocaust in terms of "bad outcomes". You don't seem to present any evidence that something much worse was on the verge of happening and was prevented by the holocaust. Based on the empirical evidence of history, there is an extremely slim chance that something worse than the holocaust would result from preventing the holocaust.
-> therefore, weighing the deaths you could potentially have prevented against the ones you could potentially cause, on balance it is almost certainly *more ethical* for you to kill Hitler and prevent the holocaust than not to do so out of fear of something worse. | 15 | 36 |
Are swimming pools breeding chlorine-resistant organisms? | Like the overuse of antibiotics. Are we breeding super microbes through the use of pool chlorine? | If you think of microbial resistance in human terms, it makes more sense. If you send out a plague that kills a lot of people, some will survive and will likely be more resistant. The plague is a very specific, complicated way of killing an individual. Now if instead, you threw every human in lava, nobody would survive to develop resistance. Lava is simple and direct, and you can't have a "lava doesn't kill me" gene.
Think of antibiotics (specific, complicated, potentially survivable) as the plague, and the chlorine as lava (non-specific, simple, very difficult to survive). | 1,613 | 1,448 |
I think time zones should be eliminated and that the whole earth should use one central time. CMV. | In the past all cities used their own time. So even cities that were quite near to each other could keep time that differed by 10 minutes for example. Starting from the 19th century, we began to use time zones. (Mainly to make it less confusing to travel with trains. The world got smaller.) The next logical step, I think, is using the same centralised time for the whole world.
The internet has made the world very small. We can travel to the other side of the world in a day. Having time zones in the modern times is just confusing. Having a centralised time for the whole earth wasn't logistically possible in the past, but it is now.
Yes, it's perhaps a bit weird at first to wake up for work in the "morning" at 17:00, but after a few months I'm sure this feeling will fade. The advantages are greater than the disadvantages. Or are they not?
Change my view. | A large number of mental models and systems are based on a common experience with time. Everyone wakes up at the same time and goes to bed at the same time. Jobs are 9-5. Prime-time TV is 5-9. Hours of operations for most buildings are the same. If you get rid of time zones, then this order is shattered. Every single city across every nation would have different workplaces deciding when work would start and end. Schools would have different start and end times. This would cause a lot of confusion for locals. If you are traveling then you will be completely and utterly lost. Let's say you travel from NYC to LA. Now you will be unable to figure out when shops close, work starts, rush hour is expected, etc. without looking up each one individually.
This also skims over the massive costs in switching over to a new system. | 89 | 37 |
Why did humans develop the Instinctive Drowning Response? It seems extremely ineffective. | For those of you who don't know what I'm talking about:
A drowning victim remains vertical in the water, has their arms extended to the sides alternately moving up and pressing down, their mouth alternates between above and below the surface of the water, and they can't move their legs or call for help.
[Video of Instinctive Drowning Response](http://captainrande.com/post/8178254793/video-of-instinctive-drowning-response-by-mario)
I can't think of a situation in which this would help a drowning person survive (except when trained professional rescuers are present). It seems like it would be a lot more effective for humans to lie on their backs and float or something.
So, why would this strange, seemingly ineffective instinct develop? | It may help you to remember that seemingly complex instincts or behaviors may not be selected for in their entirety as a single unified trait. More importantly, it's important to consider the fact that natural selection most often works as selection against deleterious traits rather than progressing toward seemingly long-term evolutionary goals (in this case, a hypothetically advantageous response to drowning). The big question, in other words, is why this response has not been selected against. | 22 | 45 |
[Star Wars]How did the Galactic Republic manage to fund such a fast military build up? | And also how was it feasible to maintain such a massive military? I mean between losing such large tax paying corporations to the seperatists, and constant warfare that would affect trade for several decades. It seems difficult to maintain a economy under these conditions. | The initial buildup of manpower and hardware was conducted over a period of at least a decade by a third party contractor outside of Republic space. This Grand Army of the Republic was built in secret, creating the illusion of spectacularly rapid militarization when this military asset was finally revealed and deployed. Securing such a deal before the economic blow of the substantial tax losses would be eminently feasible; the corruption prevalent in the Republic at this time would also allow it to be done in secret.
After the Supreme Chancellor received Emergency Powers from Sen. Binks, he was in a strong legal position to secure defense taxes from planets which had remained (often coerced) within the Republic's fold. | 43 | 37 |
Do we lose memories, or only the ability to access them? | For example, I can't recall what I did on a particular day one month ago. Is that information no longer available in the brain, or is it still hidden away in there?
When looking at people such as 'rain man', and others with a similar condition, they're able to recall nearly everything they read, the weather on any given day in the past, what they had for dinner June 3rd, 1983, etc. Do we all have that information somewhere inside of us? Do I know what I've eaten every single day of my life, but I'm just unable to recall it? | This question hinges on some hotly debated topics in memory research that try to define how and where memory representations are stored in the brain. There is no good, definite, or agreed upon answer to this at the present time. However, the simple answer to your question is that a loss of memory is usually a loss in ability to access that memory. I'll give you a scenario that is easy to relate to first, and then mention some published research.
You are going to the grocery store, and you have five different item to buy that a friend, parent, or significant other asked you to pick up, and don't have a list or any way to contact them. If you remember the first three items perfectly, but don't quite remember the last two, do you give up and go home? You would most definitely walk around the store, hoping something would cue your memory and you would be able to buy what you need. You memory of the 'forgotten' items was not immediately accessible by free recall, but would be accessible with better cues.
Events at the time of test/recall/recollection are very important in determining whether you will be able to produce a certain piece of information. There is a ton of research in this area. An interesting paper by Malthup (1995) that used a 'false fame' procedure created by Larry Jacoby. This procedure involves asking participants to read/pay attention to a list of made-up, non famous names. Then after some time (a day, a week etc.) bring those same people back into the lab and test them on a new list of names that contains some names from the previous list, some new nonfamous names, and some names of famous people. Then participants are asked to rate the fame of the names presented. Names that were studied from the previous session, although they are fictitious and not associated with any level of fame, are consistently rated as being more famous than fictitious names presented for the first time at test. Older individuals are reliably shown to be worse at this task (i.e. rate studied names as famous more often) than younger individuals. Malthup manipulated this task by specifically telling participants the three options for names they will see (i.e. famous name, new nonfamous names, and old nonfamous names). In this context older adults performed as well as younger adults. This is just one example of how memory for certain events can be thought of as 'lost' because they are simply inaccessible at the moment, or need to be probed, cued, accessed in a different way. | 126 | 581 |
ELI5: Why is water so difficult for 3d animation? | Water presents a number of challenges. First off, since it's a liquid it can move in a huge variety of ways, which means it's difficult to simulate well, and the more accurate you want to get, the more computational time it's probably going to take. If you're simulating something where the water is constantly moving (a river, or waves on a shore), that's a lot of work to be doing if you want it to look really good. A common method of doing this is having the computer represent the water as a whole bunch of spheres that collide with each other and with the surrounding geometry. This determines where the water is going, and then graphics shaders render it to look like a continuous liquid rather than separate spheres. The more spheres you add, the more fine grained and realistic your water moves, but the more you increase the computational requirements.
Second, water is mostly transparent, but not entirely. So for it to look good, you want to be able to see through it, but not have it be completely clear. If there's enough water, it eventually absorbs a significant amount of light, and not equally across all wavelengths. So you have to try to get that right. Also if you're looking into the water from above it, you get refraction, and if the surface of the water is moving and/or has waves/ripples/etc. then that's even more complicated.
Third, while being transparent, water is also reflective. So there's another layer of complication, and again it gets even crazier if the surface of the water is in motion.
Now, a lot of this stuff can actually be simulated pretty realistically, and we've figured out ways to make it look good. But the better of a job you want to do, the more work the computer needs to do, and if you're playing a game there's only so much processing time that the computer can spend on water for each frame.
So a lot of times various tricks/shortcuts/etc. are used to make something that looks good enough that we'll accept it as water, even though it's not a particularly accurate simulation. | 39 | 18 |
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CMV: The "credit reporting" industry is a complete scam | I've been thinking about this off and on for years.
The "credit score" industry:
* Has a proprietary formula for calculating credit scores
* Obtains your personal financial information without your consent
* Is prone to errors in your personal information
* Is prone to hacking
* Will charge you extra money for a subscription so you get "more accurate" data
* Will deduct points from your score for paying off loans or closing credit card accounts
A good "credit score" is required to get decent rates from banks or lenders.
How is this industry allowed to exist? How did they get permission to obtain all of my financial information? Why can they seemingly deduct or add points to my credit score for whatever they feel like? Why is there no standardization for their proprietary formulas or regulation for their security protocols?
Everything about this feels wrong and has felt wrong for the last 10 years I've been aware of these companies.
edit: why does reddit formatting not work? | Well, to start off, they **do** have your consent. When you sign up for a credit card, loan, apartment, etc. there is a little provision in the contract that says they will be sharing your information with credit monitoring agencies. Now, we can argue whether or not this is _fair_ given the way the market works and how you don't have many options where this clause isn't included, but you still agreed to it when you signed the paperwork.
The idea of a "credit score" isn't a bad one. Lenders need to know how big a lending risk you are before they decide whether or not they want to lend you any money (or at what interest rate they should give you). To determine that, they need to know you _history_ with other lenders. If you have a habit of not paying anyone back (on time or at all) then you are a bigger lending risk than someone who has never missed a payment a day in their lives. It is _fair_ that a person with good borrowing history get better rates and higher loan amounts than someone with a poor history. Since there are so many lenders out there, you need someone to aggregate this information - it is too big a burden to ask every lender to maintain the records of _every other_ lender out there.
It is also worth nothing that the "score" itself isn't all that meaningful - it is a distillation of all the information the agencies have into a number that is understandable to you as a consumer. People who actually _use_ this information don't go by the score - they go by the history of transactions you have with other lenders and use the individual transactions to assess your risk level. The "formula" is meaningless in the world of real lending.
Now, there is a real discussion to be had about the security measures that should be in place to protect this data, both because of the Equifax hack and the general level of credit fraud in this country. However, this is a discussion about how to make the industry more secure, not about its value to the lending industry as a whole. | 331 | 1,282 |
[iron sky] how does every single space capable country on earth manage to create their own combat spacecraft without the US noticing it | i mean its really easy to follow a rocket liftoff, and there are only four countries in the planet with their own rocket capabilities (the US, russia, china and india) so how does every single country manage to put enough resources in orbit to create the entire international space fleet | The European Space Agency provides launch capabilities to 22 countries (using a launch site in French Guiana), and Japan, Isreal, Iran, and North Korea also all have orbital launch capabilities. The UK had launch abilities in the past, and there are numerous private organizations now getting into the field, with the potential to launch outside of any direct government involvement.
In the world of Iron Sky, alongside the United States re-investing heavily in the space industry for its return to the moon and combat spacecraft program; many other countries followed suit with their own heavy investments into domestic space programs. Their combat spacecraft were launched under the guise of scientific programs and manned space stations - basically the same way the US did it. | 17 | 23 |
ELI5: Why do leftovers taste different than freshly cooked food? | Foods as they heat and cool change structurally and chemically. They continue to break down over time. Things that are higher in acidity more quickly. Sometimes this is a good thing, as flavors meld and sugars are released (its why spaghetti is always better the second day). | 20 | 23 |
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It seems like a common perception that sociology doesn't produce theoretical "advancements" in comparison to economics. Is this view unfounded? What would be your best examples against it? | To clarify: economists can often point to applicable models typically accepted as "true" by the majority of the profession, such as comparative advantage or the Solow-Swann growth model. The assumptions of these models are typically rigorously stated and then often reviewed and updated, such as the discarding of the Harrod-Domar model or "old Keynesianism". The sophistication of these models increases over time, seen in the behavioral revolution or the incorporation of information-asymmetry.
However, it seems that in comparison sociological theory tends to be more decentralized and "textual", and sociologists aren't as amenable towards theoretical generalization. As a result, there isn't an identifiable 'research program', and sociological or social-theoretic models don't receive the same process of innovation and updating as they do in economics. Is this a misconception? Can you point to a robust model, an 'impressive' or 'counterintuitive' result or theoretical innovation in the past few decades?
Also to be clear, I don't have any prejudices towards these fields and think that sociologists and anthropologists still do great work, I was just a bit curious | One recent advancement is the idea of neighborhood effects—the idea that effects of the neighborhood independent of the family and the region, and just moving people across the city could have important effect on life outcomes. It is most famously associated with people like Robert Sampson (lots of other have also worked on neighborhood effects). Economists like Raj Chetty have recently imported this insight to economics.
The recently deceased Devah Prager initiated the trend of “audit surveys”, where a researcher might submit similar resumes to several jobs, varying the resume only slightly. Changing the name from a “white” name to a “black” name, for example. Or changing the club from a gay rights club to something less politically relevant. Or changing male to female. Or indicating a criminal record. All of this has done a good job of showing in new ways how, even in our modern job market, even in modern liberal cities, inequality can be reproduced. These sort of labor market experiments have also become mildly popular in labor economics because they’re experiments even grad students without a grant can do.
And for a more classic example, we have Boudieu and *Distinction* . Even among Gary Becker’s protégés in economics who wanted to make the economics of everything still treat humans preferences as mostly black boxes—people have their ranked preferences and that’s that. See for example Becker and Stigler’s paper * De Gustibus Non Est Disputandum*. Bourdieu, and his students, have tried to look at what goes into what he calls “taste” (which is essentially equivalent in many ways to the economists’ “taste”), particularly how different classes have different tastes and tastes both reflect and maintain the social hierarchy. Another great book about this is the earlier *Learning to Labour*, which is an ethnographic study of “why working class lads get working class jobs”. How even promising working class students may be pushed towards working class jobs by culture, against utility maximizing economic explanations (economics can explain how really it’s “utility” for these people not to go to university, but it’s certainly not the obvious explanation). This sort of thing led Bourdieu to argue that there’s cultural capital (what you know) and social capital (who you know) that are as important to socio-economic outcomes as economic capital. | 34 | 38 |
What happens in the brain when a deaf (from birth) person reads? | I was thinking about how when I read silently to myself, I "hear" the words I'm reading in my head. When I read the word "window" I "hear" it, know what it is, and continue on. I don't "see" in my mind's eye a picture of a window unless I need to (e.g. to solve a puzzle I might picture various kinds of windows).
Then I wondered, for someone who has never heard the the pronunciation of the word or know what it sounds like, what happens when they read the word "window"? Do they picture it in their mind's eye or does something else entirely different take place? | I'd like to add a follow up question.
I recall hearing that deaf schizophrenics experience sign hallucinations rather than voices in their heads. Would this be in the same relative area as to what would be happening here with deaf people reading?
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[General] If you combine the DNA of two different species to create a race of super monsters, how do you classify it taxonomically? | I'm cloning a race of tarantula/grizzly bear hybrids as a funny joke and to reign terror upon my enemies, but I don't know how to classify it when I publish my findings.
They're morphologically more similar to grizzlies, but have about .003% more tarantula DNA (as well as a little sea cucumber "filler" DNA). What should I do? | It's not really necessary to classify your new organism unless you plan to create a large, stable, breeding population or if you plan to patent the genome. For now just calling them transgenic grizzlies (*Ursos arctos*) is sufficient.
If your creations are able to interbreed with each other, produce viable offspring, and manage to establish a population in the wild, then you might start thinking about taxonomy. | 46 | 43 |
ELI5:how would I calculate the rain flow into a water tank off a given corrugated iron roof structure? Say I had a four square metre roof and the given average rain fall (say it was 1000 mm annually)? | I'm building a water tank system for an off the grid property- just for occasional use, so a 1000 litre tank. I want to get the optimum results without massive wastage or shortfall so some ideas would help. Thanks in advance. | Even if you can say you'll get a consistent 1000mm per year, your figures will only be vague and will vary. Rain doesn't often fall vertically, and your roof may or may not be flat. If your local winds tend to blow rain towards the east, and you're collecting rain off a roof that slopes away from that direction, you won't collect much rain.
If we simplify it by looking at a completely flat roof with vertical rain falling on it, we can just treat it as a volume, that is we just multiply the area by the depth of water we get - so 4m^2 * 1000mm = 4m^3, which is 4000 litres over a year. | 11 | 33 |
ELI5: What's the difference between a Senior Vice President and a Vice President of a company? | Are their duties completely different? Why the difference in the titles? I notice, like at General Motors, there's a lot of both. | Strongly depends on the company. In some companies, it's an executive position. In others-- especially client-facing ones such as banks, consultancies, and marketing agencies, VP can be a popular title for most mid-career positions. This started out as a way to make clients feel that they were interfacing with someone important, but it's since then drifted into non-client-facing roles at those companies due to title inflation. Mid-level (not even managerial) corporate employees at investment banks, for example, tend to be VPs. Their bosses are SVPs. In other companies, they would be managers, directors, or maybe VPs. | 11 | 26 |
ELI5: What is Heisenberg's uncertainty principle in layman's terms? | EDIT: Past the basics i.e. "The more we know about something's speed, the less we know about its location." | In the simplest terms, anything we do to try and detect the location of a particle will change its speed. In the same way, anything we do to try and measure its speed will change its location. It's a matter of measurement and sensing sciences, which we cannot (at least yet) surmount. Heisenberg's theory is that it is impossible to know both at once. | 11 | 16 |
CMV: Presidents and members of their administration should not be invited to the WHCA dinner | Presidents dating back to Calvin Coolidge have traditionally been invited to the annual WHCA dinner, a charity event with awards for journalistic excellence and typically featuring a comedy roast of politicians and members of the press as well as a skit or stand-up performance by the President. The event serves as a moment to celebrate the work of the press corps and also as a fundraiser for journalism scholarships.
I believe that the current level of friction and distrust between the press and Trump highlights a problem with the WHCA: they have generally enjoyed congenial relationships with past presidential administrations, and their comparatively rough treatment by the Trump administration strikes them as unnecessarily hostile.
My attitude is that I don't *want* the press corps to expect a collegial relationship with the administration. I want the press to investigate the president and administration constantly, ask them tough questions, and essentially police them. The relationship between the WHCA and the administration should be at least somewhat adversarial. It can be polite, or openly hostile, or anything in between, but the two sides should not be buddies. Therefore, an annual event which encourages them to behave like buddies is a bad idea, and ought to be changed.
I think the WHCA should formally un-invite Trump and his administration from this year's dinner, and should not invite them (or any future presidents or administration officials) to future dinners. They should continue to hold the dinner, invite comedians, roast each other and the politicians they cover, raise money, and have fun. But I want them to build that fun, collegial relationship with *each other* and not with the administration.
To clarify, I am not saying that making this change (on its own) would fix anything between the president and the press. I think it's just a small thing that would help to ensure that the press maintains healthy expectations about its relationship with the administration.
> *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!* | One of the great positive aspects of the WHCA dinner, traditionally, is that it has been a reminder that the press and the government, while not on the "same team", kind of are.
Its a chance for the people involved to sit down, have some laughs, and remind themselves and each other that any adverse relationship is strictly business.
When you cut the White House out of the event, it goes from being a fun, well-intentioned roast to being a bash session.
There is no way that you can have a positive working relationship between two groups when one of them holds a publicly televised event for the express purpose of shitting on the other one.
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ELI5: Why do coffee makers suggest you start with cold water? | If the machine makes it hot in the end, whats the purpose of using cold water? Specifically is there any scientific reason that using cold water could the way the coffee turns out in the end? | Hot water is more likely to pick up minerals from your pipes. It will have a higher metal concentration than cold water, so cold water is "cleaner".
Not sure how it impacts the taste of coffee but it is fully reasonable that it could, they are just recommending cleaner water. | 25 | 26 |
ELI5:The structure of songs - verse, chorus, bridge, breakdown etc. | This is an interesting question, let me give it a shot.
**Verse:** This a part of the song where the lyrics are unique generally take the place of the melody, but not necessarily. The other instruments usually play the theme or something generally simpler so that the lyrics can more easily be heard.
**Chorus:** This is part of the song that is repeated at least once. It can be lyrical or in an instrumental, it could be the theme or the main riff of the song that appears a lot, this definition is used primarily in Blues and Jazz.
**Bridge:** This is a lead into another part, and can either be instrumental, lyrical, or both. Often goes in between the verse and the chorus, or a solo and the chorus/verse.
**Breakdown:** This is a part of the song where everything is a lot simpler. The guitars/bass usually play a driving riff on one or two notes, and the drums play a simple driving rhythm.
Most songs have a verse-chorus structure, which is more or less intro-verse-chorus-verse-chorus-solo-chorus-outro. Bridges can be introduced before the chorus, and are often called pre-choruses if they have lyrics, or after the solo or the intro. Many bands also add solos in between choruses and verses or may do verse-verse-chorus or something. But that's the general structure. | 12 | 21 |
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Particle entanglement says distance between particles is irrelevant for one to affect the other instantaneously. What if the particles are a light year apart? Does that mean the speed of light really isn’t the universal speed limit? | It's arguable if "one particle affects the other", since entanglement can't be used to send information faster than light. In the back of Griffith's QM book, he says it's analogous to a planet passing in front of a star. The planet's shadow moves faster than light, but it's irrelevant since no information is transmitted. | 62 | 56 |
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ELI5 why is directly looking at a solar eclipse bad for your eyes? | Your eyes adjust to the total light in your field of view, not the brightness of any particular object in your field of view.
So during an eclipse, there's less total light, however any visible portion of the sun is just as bright as it is usually, which is bright enough to physically damage your eyes.
Thus, your iris will accomodate by expanding, allowing even more light than usual in, when the light is already intense enough to cause harm normally. | 32 | 27 |
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Question about atheism and moral realism | I've been thinking about how there might be a double standard with atheists who are also moral realists. They reject all arguments trying to prove the existence of God, including the "feelings argument". i.e. the argument that says that through prayer, meditation, etc one can "feel" the presence of God(s) and therefore God(s) must exist, but this argument is rejected for being "queer" and/or through a demonstration to prove that these "special feelings" are merely emotional experiences, but when it comes to the atheists who accept robust moral realism, there is a sudden reversal, i.e. the feelings regarding ethical issues are "special" and reveal to us mind-independent moral facts. Are these "feelings" actually different enough to show that the two arguments are not equivalent, or is there indeed a double standard here? | There's an interesting question in the vicinity here about what exactly religious-experiences are and what exactly ethical-intuitions are.
If religious experiences are intuitions, then there's a kind of double-standard charge available. Maybe some religious-experiences are indeed intuitions. But they differ from ethical intuitions in a few ways.
For one thing, moral realists can appeal to ethical intuitions that seem to be very difficult to doubt, e.g. that worlds are better when they contain more happiness, that it would be wrong to kill every sentient being in the world, and so on. But it's obviously easy for many people to doubt that God exists.
For another, ethical intuitions are normative, but the intuition that God exists is descriptive. It's not easy to say where we would acquire normative knowledge if not through intuition, but that sort of argument isn't as easily available about descriptive knowledge. Someone might say, though, that God is alleged to be non-physical, and we acquire knowledge of the non-physical through intuition.
But as /u/Samskii and /u/GFYsexyfatman note, part of any debate is considering the evidence for the opposing side. Moral-realist atheists are free to grant that intuitions are prima-facie evidence, and many of them do indeed grant this. (I do, for example.) They can simply argue, however, that there are rebutting or undercutting defeaters for theistic intuitions.
The undercutting defeaters, if they exist, could be attempted debunking-explanations of theistic intuitions, although those might prove too much vis-a-vis moral realism. Better would be to argue that descriptive intuitions tend to be less reliable, as far as we know, than ethical intuitions. At the very least, someone could throw into doubt various *particular* theisms, even if there's widespread intuitive agreement that some kind of deity exists. But here, as noted before, there seems to be less intuitive agreement about that (especially among experts) than there is that, e.g., lying is prima-facie wrong.
The rebutting defeaters, if they exist, would be the background-improbability of various gods, and in addition, in some cases, evidence (e.g.) of the existence of gratuitous evil, which is arguably incompatible with at-least classical or Anselmian theism. | 20 | 16 |
Why is the average height of humans increasing over time? | Napoleon, who was known for his short stature, was average height in his day. During the American Revolution, the average male height was 5'6.
Does this mean that taller people are "fitter" to survive? | Increased access to nutrition and healthcare has lowered rates of stunted growth in children. Global development has limited famine and lowered disease loading that draws on energy that would otherwise go to growth. | 39 | 15 |
ELI5: Why do we and other animals get so excited for food, but not so much for water, even though thirst is a more immediate concern? | Food generally requires more effort to get than water. Generally, you have a known water source, but you have to hunt or gather for food. If you don't have a water source, then that does become the immediate concern, but you can get some amount of water from food too.
Thirst can get desperate and will kill you faster than hunger, but water is still either available or not. Food is still more complicated to acquire. | 117 | 122 |
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ELI5: What is the so called Axis of Evil and why does it trouble astronomers? | Basically there is an underlying assumption that our universe should look essentially the same from any location, and that there's nothing special about where we are in it.
The Axis of Evil is an anomaly in the background radiation of the observable universe, which appears to line up oddly with our position.
If that were true, it would seem to suggest at least the possibility that the earlier statement is flawed, and raise quite a few questions about *why* our position is 'special.' However, there's definitely not strong agreement that this is actually the case, it has been suggested it could be coincidence, noise in how the data is processed, less significant than believed, or simply an error, among other ideas. | 2,848 | 3,788 |
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I think I should go around telling a lot of the people in CMV that they have great views that don't need to be changed, CMV. | I was just reading the rules and I noticed that responding to OP is limited to challenges to the view and clarifications on what is being said.
I am bothered that I can't support their views directly and encourage them to feel good about their naturally formed opinions. | Consider the possibilities for each OP you encounter.
Possibility #1: The OP is posting in this forum specifically because they want their view challenged. They are either secure enough in their view that they aren't actually worried about said challenges, or they genuinely want to have their view changed. Thus, they won't particularly enjoy having you reassure them about their existing view.
Possibility #2: The OP is here fishing for compliments, or with intent to troll, or is otherwise violating the spirit of the subforum. They might like getting your support, but do you really want to encourage people to do precisely what this sub *isn't* about?
If you really want to let someone know you like what they have to say, just send them a personal message. | 51 | 67 |
ELI5:How do music apps like Shazam work? | music can be converted into a digital data format that describes (in a format that can be understood by a computer) the sound that the music is made of. this usually involves sampling the music at a very high frequency rate (for example, 192,000 times per second) and recording the amplitude and frequency of the sound wave at each time instant sampled. this digitized data can be used to do computing on the recorded music.
one form of computing on the recorded music is playback. this is what you're most familiar with. its the basic function of an iPod or any kind of digital music player. another form of computing on recorded music is analysis. this is what Shazam is doing.
I don't know the exact algorithm that Shazam is using but is is highly likely that the program produces a kind of "summary" of the recorded music (sometimes by producing a histogram, or some other kind of meta-data). then it searches through a database of known "summaries" until it finds a match. there is a high likelihood that the match of the two summaries indicates a match of the complete song. | 28 | 128 |
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Eli5 Why can't we have transparent metal? | I'm guessing that the crystalline structure scatters the light. Polymers are semi crystalline and also scatter light, but we have amorphous polymers that are transparent. Why can't we have something similar with metals? | Metals are full of free electrons which have electric fields that reflect the incoming photons/electromagnetic radiation. So metals are not transparent to light for the same reason they are conductive to electricity and heat. | 219 | 140 |
How can a material remain radioactive after it has been exposed to radiation? | I was watching TV today and the topic of the Fukushima nuclear accident was brought up on the news and the reporter had mentioned "radioactive water" which got that way from exposure to radiation from the Fukushima nuclear plant. I just wanted to know how a substance, such as water, can remain radioactive just because it was exposed to either alpha/beta/gamma radiation. What is the mechanism that makes this work? For example, if I expose a glass of water to a bunch of xrays or gamma rays, why is that water no longer safe to drink? How does radiation stay within the substance? | It's important to recognize the difference between radiation, and radioactive material.
Radiation is the particles and waves which are emitted, which can be ionizing or non-ionizing.
Radioactive materials are atoms which are unstable and emit radiation.
Some types of radiation can cause other materials to be radioactive. But in the case of Fukushima, the water itself is not what is radioactive. The water came into contact with the melted core material. The melted core material IS radioactive. Some of the melted core material dissolves in the water, and now the water carries the melted core material with it. So the water itself is clean, but it has dissolved radioactive materials and particles with it.
If you were to use ion-exchange and other types of filtration to separate the radiaoctive particles from the water, the water would come out clean and virtually non-radioactive. | 20 | 18 |
CMV: The government should stop recognizing ALL marriages. | I really see no benefits in governmen recognition of marriages.
First, the benefits: no more fights about what marriage is. If you want to get married by your church - you still can. If you want to marry your homosexual partner in a civil ceremony - you can. Government does not care. Instant equality.
Second, this would cut down on bureaucracy. No marriage - no messy divorces. Instant efficiency.
Now to address some anticipated counter points:
The inheritance/hospital visitation issues can be handled though contracts (government can even make it much easier to get/sign those forms.) If you could take time to sign up for the marriage licence, you can just as easily sign some contract papers.
As for the tax benefits: why should married people get tax deductions? Sounds pretty unfair to me. If we, as a society want to encourage child rearing - we can do so directly by giving tax breaks to people who have and rare children, not indirectly through marriage.
CMV. | > The inheritance/hospital visitation issues can be handled though contracts (government can even make it much easier to get/sign those forms.) If you could take time to sign up for the marriage licence, you can just as easily sign some contract papers.
That's what marriage *is*. It's a kind of contract that include a bunch of specific rights. Giving people those rights is still marriage, whether you call it that by name or not. It's like saying "We're not going to give out sandwiches anymore. Instead, we will be serving meat, vegetables and condiments between two slices of bread". It's the same thing.
You're just saying we should change the name, but there's really no benefit. Marriage has been a legal institution as long if not longer than it's been a religious ones. Why should the state arbitrarily decide to start calling marriage something else?
> Second, this would cut down on bureaucracy. No marriage - no messy divorces. Instant efficiency.
If you're going on to keep civil unions, you're going to also have to deal with the dissolution of those unions. No efficiency gain here. | 253 | 519 |
ELI5: The ratings of engine oil, i.e. 5w10, 5w30, etc. | These oils with 2 numbers, like 5W-30 are called "multiweight" oils and protect the engine under a wide range of operating temperatures.
This rating indicates the engine oil thickness when cold (the first number) and when hot, at an engine's normal operating temperature (the second number). The higher the number, the thicker the oil.
Thin oil flows better, but does not protect the engine as well as thick oil, under heavy loads.
So we want an oil that is thin when cold, so it flows into all the tight spots in an engine on a cold day start up, to lubricate the engine better.
But we also want an oil that behaves like a thicker oil when its hot, to protect the oil under heavy operating loads.
These multi-weight oils provide such a wide range of operation. Engines are usually designed to use a specific thickness of oil. So look to the owners manual to see the type of oil suitable for your car.
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I believe that punishment should be based on the action taken alone, and the consequences should have absolutely no bearing on it. CMV. | First and foremost, my apologies if this is a repost- it seems like a somewhat obvious CMV candidate. I could find no post like it though, so please delete this and redirect me if this view has been expressed before.
It is hard to significantly expand on the view as presented in the title; I believe simply that, in accordance with any account of punishment I am familiar with, it is both more productive and fairer to disregard the consequences of the action. For example, I believe that the penalty for causing death by drunken driving should be the same as that for simply being caught drunkenly driving. Whether that is achieved by raising the latter or lessening the former is a difficult problem to consider, but a separate one.
The aforementioned consequence of my position is the main reason why I would like to have my view changed; it is uncomfortable to have to defend the position that someone who recklessly causes the death of a child should receive what many would consider no more than a slap on the wrist. I have yet to be convinced, however, that the driver in such a case is any more deserving of punishment than a driver who makes it home without incident at the same level of intoxication. So please, my good redditors, CMV. | This idea gets a little bit messy in practice, because luck and circumstances play a role in virtually all actions. In your drunk driving example, how would you punish someone who *intends* to drive drunk but passes out before they start the car? Or what about someone who *intends* to drive drunk, but then is offered a ride by a good samaritan? Are they as bad as the person who managed to drive drunk? If not, it seems like you are giving them the benefit of the doubt due to consequences outside of their control, which goes against your guiding principle. If we knew with certainty that they were going to drive drunk before they got lucky, should we still punish them?
We generally stick to consequences rather than intent and potential consequences because there's such a massive disparity in action and consequences based on events outside of our control. | 15 | 16 |
Why is learning Economics good for daily life? | I'd say the average person benefits most from a decent understanding of economics because we live in a democracy, and it's important, to the furthest extent, people be informed on the people and polices they vote on and the implications thereof, and since many campaigns and policies are economic in nature, it makes sense for people to research and have a decent economics foundation. | 34 | 19 |
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ELI5:How can Wim Hof raise his blood pH through the use of a breathing technique, directly influencing the immune system? | ^ | I have no idea who/what Wim Hof is, but breathing absolutely influences your blood pH. When carbon dioxide is in your blood, it is converted to H+ (protons) and HCO3 (bicarbonate), which are both dissolved in your blood. H+ (protons) is what determines pH (more H+=lower pH, less H+=higher pH). When the bicarbonate reaches your lungs, it is converted back into CO2, which can be exhaled.
Therefore, if you increase your breathing rate (hyperventilate), you will blow off more CO2, which will decrease the amount of HCO3 and H+ in your blood, which will increase your blood pH. If you decrease your breathing rate (hypoventilate), you will retain CO2, which will increase the amount of HCO3 and H+ in your blood, and decrease your blood pH.
This is a well documented phenomenon in diseases that involve acidosis (decreased blood pH). One of the best examples of this is Diabetic Ketoacidosis, in which the low insulin levels result in a low blood pH. One of the classic clinical presentations of Diabetic Ketoacidosis is hyperventillation, because the body is trying to blow off extra CO2 in order to raise the blood pH. | 27 | 44 |
Could someone explain why gravity doesnt fit in with other areas of physics for a unified field theory? | Thank you for thinking about answering my question! | There are four fundamental forces that we know of. Three of them appear to be 'quantized'. This means that they come in discrete packets. In other words, there is a single "unit" of light energy (plank's constant) that is fundamental and indivisible. This is analogous to zooming in on light and finding out that it's pixelated¹.
Gravity, on the other hand, resists quantization. Quantized gravity equations go haywire and give you infinities. This is analogous to zooming in on gravity and finding out that it's continuous.
Different people have different intuitions about whether the universe is pixelated or continuous at the small scale, but it can't be both: our continuous model of gravity doesn't work with our pixelated model of light (& the other forces) on scales where there is a lot of energy in a small space (e.g. black holes).
¹ Pixelated in terms of how much energy it carries, not in terms of its literal position. Position still seems continuous, which is directly related to why gravity is continuous. See below. | 53 | 30 |
CMV: Attendance should not count towards the final grade in a college course. | When I was in high school, it was continuously stressed that the individual had no cap on their freedom in college, for lack of a better explanation. I was told time and time again that students were able to eat in class, or sleep, or play on their laptop, but I am now in my senior year and have realized more than ever that these things are not true in the least.
Professors care more than it appears. I personally find it disrespectful to attend class and not give the professor the undivided attention they deserve, and if you don’t believe me, let me know how they react when you spend class time playing on your phone and then wonder into their office at the end of the semester in search of extra credit.
Although I believe professors deserve undivided attention from the students during class time, I do not believe that students should be required to attend class and forced to watch their grade suffer with each absence.
First and foremost, if a student is able to regularly miss classes and still pass the course, they are either qualified to move on given their knowledge in the subject, or the professor should step their game up, as the content is obviously too easy. Furthermore, college students know better than anyone that life is not a walk in the park; everyone has their own shit to deal with, and sometimes it really is inconvenient to attend class. College students pay tens of thousands of dollars each school year, why should they not be allowed to skip a class or two if they want? Some professors I have had in the past have given two free skips, where the attendance grade is not lowered until the third skip.
If a student misses a class where there was a quiz or an important announcement made and they have no “legitimate” excuse, it’s completely on them and they should be given no special treatment. Besides, depending on total enrollment price, each class missed could be a couple hundred dollars down the drain.
But maybe i’m wrong. CMV.
| One thing that "having a college degree" implies is that a person is "disciplined" enough to set a goal and follow through on it.
In college, unlike high school, nobody is forcing you to go to school. Nobody is forcing you to go to class. Therefore, your ability to attend class indicates how disciplined you are. And this is something employers want to know. Can you follow instructions and be where you're supposed to be even if you don't feel like it? If a college professor makes attendance part of his final grade, it's because he believes having the discipline to attend all the classes is an important element of the students' development, and employers think so as well.
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ELI5:Why is Judge an elected position? | So in my state (California) we elect judges in the same way as all politicians. Unlike politicians, they don't campaign. I had to spend a fairly significant amount of time searching to find anything about them. This seems like a dumb way to choose judges given that many people might just choose randomly or vote for the cooler sounding name. Why is it done this way? And why do they not campaign like other politicians running for office do? | Perhaps not the answer you're looking for, but electing judges (and a few other legal professions, such as district attorney) is an almost uniquely American habit. Much of the rest of the world (certainly that which is based on the British legal system) performs judicial appointments via the legislature or executive, or from within the judiciary itself. Seems to be working out fine for us so far. | 38 | 92 |
ELI5: What actually happens when a program stops responding? Why does it sometime crash and other times continue working? | Let's start off with your operating system. That's going to be Windows, etc. That's your overseer within the computer, and it communicates and interfaces between you and the other applications inside the computer.
Normally, the operating system (OS) is freely communicating between you and the programs, but sometimes, this communication breaks down, which is to say the program isn't responding to the OS's requests. This can be because of a bug in the program, or because the program is busy doing its thing and doesn't bother to respond to the OS.
Sometimes, the program just needs a little time to catch up, and when it gets finished with its current task, it reestablishes communication with the OS and the program continues working. Sometimes, however, the program gets caught up in its own thing and runs around in circles over and over again. The program isn't going to respond. Occasionally, but not always, the program may trigger a break command, which says that if that line of code is reached, terminate, because the program has found its way in Bad Place (TM) and won't be getting out. That's when the program crashes; the program has triggered its own self-destruct sequence.
But sometimes, the program just sits there and waits forever. You might tell the OS to try to close the program. If the program still doesn't respond, you can force the program to terminate, which is to basically have the OS take a gun to the program and execute it (in the sense of taking it out back and disposing of it). | 33 | 18 |
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How does Parthenogenesis work? | Given that the average person like me usually thinks of reproduction as taking the sperm and the egg, I struggle to understand how you can create something without fertilisation. Can anyone explain? | There are three major types of parthenogenesis to consider (at least in insects):
* 1) Haploid parthenogenesis: Quite common for ants, bees, and wasps. In this particular case, we have a diploid (2n) female who produces haploid (n) gametes. If the eggs are fertilized by a spermatozoa (n), the resulting offspring will be diploid females. However, if the eggs are unfertilized, only haploid males will be produced. This is known as the halpodiploid condition, in which fertilized eggs only produce females and unfertilized eggs only produce males.
* 2) Automictic parthenogenesis: In this case we have a diploid female (XX) who undergoes the early stages of meiosis to produce a secondary oocyte and several polar bodies. The oocyte will then fuse with one of the polar bodies, thus restoring the diploid condition.
* 3) Apomictic parthenogenesis: In this case, the oocytes do not undergo meiosis, so there is no reduction of chromosome number and they remain diploid. The egg then develops as it normally would. | 10 | 40 |
ELI5: Why does fertilizer explode? | Most fertilizers contain ammonium nitrate.
Ammonium nitrate is an oxidizer that reacts with other combustible materials.
Normally it's fairly safe to have around at normal temperatures. But when it's heated up to higher temperatures, or exposed to a hot fire, a run-away chain reaction can occur with ammonium nitrate to cause a violent explosion.
It's often used for improvised explosive devices, and for accelerating the reaction of other explosives, such as in some forms of dynamite. | 14 | 22 |
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ELI5: How microwaves work, such that my leftover gravy boils on my plate while my lump of cold mashed potatoes stays cold? | Eating leftovers, obviously. | Microwaves are at the right frequency to cause water molecules to vibrate, increasing the temperature of the food. Gravy contains more water than mashed potatoes, which are relatively dry, so gravy heats up much faster. | 10 | 16 |
ELI5: Why do we feel weak (as in not being able to lift a heavy object) when we are laughing a lot? | Someone may be able to correct me on this, but a good ELI5 would be that our core muscles (Abs and such) play a major role in keeping us upright and maintaining posture, and are even more active when we are also lifting something heavy. When we are laughing uncontrollably a lot of that core muscle activity is now involved in the act of laughing and not maintaining posture, to the point where in particularly intense laughter we might end up doubled over on the floor. | 22 | 24 |
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[Avatar] Why is it that some Benders don't need to move to Bend? | Bending is all about the manipulation of the flow of chi within the body and using it to affect the outside world and the element(s). The various bending arts and styles help to focus the chi into doing specific things, depending on the movements of the body.
Some particularly powerful benders, however, have such control of their chi, either from a lifetime of training or just winning the genetic lottery, that they can focus and manipulate their chi with the most minimal of movements. And in rare cases, no movements at all. Of course it's still easier for them to bend using the proper forms and stances than to do without them.
Think of bending stances and moves as sort of physical/spiritual mnemonic devices, those little tricks you learn to help you remember more complicated things; like singing the alphabet or using a phrase to remember the order of the colours of the rainbow. Most people use them a lot starting out but eventually don't need them as much. Some people never stop using them. And some lucky people just have good memories and don't ever need to use any. | 43 | 53 |
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ELI5: In felines crouching to pounce, why do they "wiggle" rather than being completely still? | I've seen many a cat, when preparing to pounce on something (a toy, a cricket, spider, or other bug, or big cats vs. prey), "wiggle in preparation" - [seen here](http://fat.gfycat.com/MeekPracticalBlackbird.gif) (from the recent [front page /r/gifs post](http://www.reddit.com/r/gifs/comments/2ecy9l/about_to_pounce/)).
While there are [plenty of answers to what is the cat doing](https://duckduckgo.com/?q=why+do+cats+wiggle+their+butts) when performing this behavior, but I've not been able to find out what benefit this serves, versus being completely still and stealthy?
I would think that the vision systems in prey, being extremely sensitive to and optimized for detecting motion, would tend to make this a "negative" for the feline about to attack, rather than a benefit.
I'd love to hear from an animal scientist or someone else "in the know", rather than wild guesses, since I'm pretty good at those already. Thanks! | The goal is to make sure they have stable footing and good balance. If you're about to push back on a patch of ground very hard to make a relatively long distance leap, it's pretty important to make sure it won't give way first.
It's important to remember that most animals don't have sight as their primary sense; humans are pretty visually focused compared to most of the animal kingdom. Even for those with relatively crisp vision, the cat is ideally not pouncing from within its field of view. | 90 | 95 |
ELI5: irrational coefficients Pi and e | Im an engineering student, and at times when Pi or e appear in formulas it makes no sense why is it there for first, and then how did it even originate.
Okay, I know how the Pi was created. But sometimes I dont understand when in formulas it appears, when there is no apparent connection to circles. ( Could be underlying physics rules though)
And the second one is natural number e 2.7.. how in the world was it created and how did someone think its going to be important for.. again.. so many formulas and equations.
I use it all the time, but when I think about it. It hardly makes sense | Without knowing the specific formulas, it would be impossible to answer why they involve pi or e. Sometimes it even baffles scientists and mathematicians.
But, e, that's easy to answer.
Imagine a bank that returns 100% of your investment at the end of the year. You put in $1 in at the beginning you get $2 out.
Let's take that same bank and compound the interest bi-annually. Instead of getting 100% at the end, you get 50% of your investment 6 months in, then 50% of *that* at the end. You put in $1 in the beginning and get $2.25 out (1 * 1.5 * 1.5)
Three times a year you'd get $2.37. (1 * 4/3 * 4/3 * 4/3)
n times a year can be calculated by the formula (1 + 1/n)^n
As n approaches infinity, your return approaches an irrational number, approximately 2.7182... and given the label *e*.
*e* is the amount of money you'd get back each year from a bank that nets 100% return and compounds your interest continually. | 22 | 36 |
Why do some medicine need to be taken on a full stomach/with food where as for others it doesn't make a difference?? | There's generally two reasons why a drug might be recommended to be taken with food. One is just that taking with food can help lessen nausea, which is a side effect of many drugs. The other is that some drugs/formulations are dissolved or absorbed more readily during active digestion. Digestion delays stomach emptying, which can give a drug preparation more time to be fully dissolved before being passed to the intestines. Digestion also stimulates the release of stomach acids, bile, and enzymes, any of which may help with dissolving certain drug formulations. Note that many drugs are specifically recommended to be taken on an empty stomach as well because any of these effects could be negative as well as positive, depending on the exact chemical nature of the drug. In a lot of cases there's actually competing effects, so the best practices have to be established by extensive study and may ultimately recommend, for example, taking a drug with a low-fat meal, etc. | 12 | 19 |
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Is Logic a priori? | I working on a master degree Thesis on philosophy of Mathematics and I am trying to demonstrate that Logic Is not a Priori. Can you share with me some of your thoughts and some papers on the argument? | Standardly it’s understood that logic is the tool we use *to do* a priori reasoning. I.e. when we are reasoning a priori we are doing logic. That being said if you tell us more about your intuitions about logic and mathematics not being a priori we might be able to help some more. | 73 | 83 |
ELIF how the square root function of a calculator works. | There are methods (called algorithms) to do it. The most famous algorithm was known even to Babylonians (and it's very similar to the method Newton invented).
Imagine you want to find out the square root of 3.
1. Pick a random number (near to the value you expect). Call it x0. (I choose x0 = 1)
2. Then, find the average between x0 and 3/x0, that's 2 ( = (1 + 3/1)/2). Call your result x1. (x1 = 2)
3. Do the average between x1 and 3/x1. Call the result x2. Continue until you're satisfied with the result. (x2 = 1.75, x3 = (x2+3/x2)/2 = 1.723, x4 = (x3 + 3/x3)/2, etc).
The Square root of 3 is something like 1.7320. | 44 | 59 |
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Why are radio frequencies split into radio waves and microwaves? | I'm doing a project for school on radio frequency and how it is used for communication. However, it has been extremely hard to find any information on why it is split into radio waves and microwaves. | Both radio waves and microwaves are examples of electromagnetic radiation. The split into various categories is somewhat arbitrary. In reality, there's a continuous spectrum of EM radiation and there are no real "hard breaks" between different parts of the spectrum. We group parts of the spectrum together with a specific name because of specific applications.
It's worth noting that radio waves and microwaves are quite close together in the EM spectrum. Depending on who you ask, they may even overlap. But it's all a matter of definition, there is no hard rule. | 58 | 137 |
Why has RESTful become the accepted way to handle data rather than stateful? | In typical web programming / app development, it’s coming for the backend to be mostly RESTful. But why is that the case? It seems that WebSocket based (or something similarly stateful) should have become an accepted use by now, but I don’t see it the proliferation.
I get that there’s a cost to keeping a WebSocket alive, but it must be very small, no? With something more WS based, your web / mobile app can instantly request the data it needs and get back only that.
Apps (web and mobile) are increasing dependent on state - in fact a core React hook is called useState. So I’m curious why more isn’t being done to promote stateful backend interfaces.
Thanks. | REST for example is great when it comes to scalability, because if you do it right, you have no dependencies between your service instances (i.e. all the state you need to handle the request is part of the request), so you can just chuck in new servers without having to worry about a central bottleneck. | 56 | 54 |
If we were all completely rational beings with unlimited time to learn and research things, would we all arrive at the same set of beliefs and views? | You want to look at the debate over epistemic uniqueness/permissivism. That's about (roughly) whether a single body of evidence could support multiple conclusions.
Roger White's 2005 paper is the contemporary starting point, Tom Kelly has some good work on this as does Miriam Schoenfield. | 23 | 26 |
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[Star Trek] What's the advantage of using a rifle-style phaser over a handgun-style phaser? | Looking into the phasers shown in TNG and other series, it seems like there's not much of an advantage to the rifle-style. Handheld, handgun-style phasers can be set powerful enough to completely disintegrate someone. Phasers don't have recoil so the second handhold isn't really for that. I don't recall anyone running out of "ammo" so the extra size isn't for that either, so far as I'm aware. I don't know of any special/extra features that rifles have over the handguns. They're heavier I'm sure, and are probably harder to handle and turn with. The only advantage I can see if that they have better aiming down the sights, but if you have a weapon with unlimited ammo that can harmlessly stun an enemy no matter where they're shot, I don't see exceptional aim as being that useful.
So what's up with the rifles? | Phaser rifles use a different targeting computer that can track multiple simultaneous fast moving targets at greater range. They are also more effective against armored or shielded opponents and small craft. The rifle can fire in beam and pulse modes and for longer periods on a single charge - and can accept an easily replaced plasma battery. Handheld phasers are good for close work and in tight conditions, but they haven't got the stopping power to disable a Klingon, Nausican, Breen, or Borg without killing them.
The paperwork for unintended disintegration takes forever. | 45 | 23 |
Does hypnosis work? | Is it a real thing? Or is it just a magic trick? And if it works, how so? Can one get hypnotized by watching videos? | Suggestion works to some degree - for example, it has been successfully used as a mild alternative to analgesia, in dentistry for example. It is in no way comparable to what is popularly shown in media (e.g. against your own will; making you think you are a chicken, things of that sort) | 24 | 35 |
I've heard people describe how they became sick when they ate meat after a long time being a vegetarian. Does one's digestive system actually change from eating a vegetarian diet, and can then eating meat actually make one ill? Or is it more of a psychosomatic response to eating meat? | I'm curious as I would assume that the body wouldn't reject a kind of food that it had adapted to consuming simply because it wasn't "used to" it anymore. | This occurs due to our bodies changing bacterial flora. our digestuve tract is filled with bacteria which are help to digest and breakdown food. When we change it diets for a long enough time the bacteria composition in our guts also changes. Thus when they would go back to eating meat it would cause digestive discomfort due to the lack of bacteria to assist in digesting meat.
However, there is also a good chance that some of the discomfort might be psychological. | 41 | 73 |
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