# Schrodinger's Cat **URL:** \ **Category:** Factual Questions\ **Created:** [January 3, 2012, 4:03pm UTC](https://boards.straightdope.com/t/schrodingers-cat/608260 "2012-01-03T16:03:55Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![whc.03grady](https://avatars.discourse-cdn.com/v4/letter/w/a6a055/32.png) [@whc.03grady](https://boards.straightdope.com/u/whc.03grady)\ **Post date:** [January 3, 2012, 11:19pm UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/41 "2012-01-03T23:19:52Z")
> [@Candyman74](#): > > Relativity sounds absurd. But your GPS works, so it’s clearly not. Quantum computers work, so it can’t all be nonsense. And Newton’s Laws are all wrong, but I can still use them effectively to lob shells at the bad guys on the other side of the hill. And Ptolemy’s theory is wrong, but I can use it to figure out where Jupiter will be next week. So what? ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [January 3, 2012, 11:22pm UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/42 "2012-01-03T23:22:13Z")
> [@whc.03grady](#): > > …(Those who are inclined to quote Whitman here can save their keystrokes. :)) But I am large!!! This is what the Cat says in the box: _I know I have the best of time and space, and was never measured and never will be measured._ ---
**Author:** ![whc.03grady](https://avatars.discourse-cdn.com/v4/letter/w/a6a055/32.png) [@whc.03grady](https://boards.straightdope.com/u/whc.03grady)\ **Post date:** [January 3, 2012, 11:29pm UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/43 "2012-01-03T23:29:23Z")
> [@clairobscur](#): > > I heard it about a liberal art major, an engineer or physicist and a mathematician (respectively saying “sheeps are white”, “at least 20 sheeps are white” and “at least 20 sheeps are white on one side”, so showing that the mathematician totally ignores common sense) Maybe that’s where Heinlein got it–remember in _Stranger…_ when the Fair Witness is asked about the color of a house across the way: “It’s white on this side.” ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [January 3, 2012, 11:34pm UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/44 "2012-01-03T23:34:01Z")
> [@whc.03grady](#): > > The assertions of quantum physics don’t just sound weird. That’s the understatement of the year. To be told that a thing can both be something and not be something, at the same time, well, that’s a lot (a **LOT** ) weirder than being told the Earth goes around the Sun and not vice versa. And yet all evidence points to it being the case. The universe is weird at certain levels, and this is one of them. And it’s just as weird as general relativity; there is stuff there that simply doesn’t make sense to the everyday world. But experiment after experiment has shown that it is the way the universe works. Deal with it. 🙂 **It’s never going to to make sense on an instinctive level.** It just isn’t. Lots of scientists had and have trouble with QM because it goes against their common sense. But you can’t really argue with experimental data. Well, you can, but either you show the data is wrong or your change your mindset and move on. ---
**Author:** ![Mgalindo13](https://avatars.discourse-cdn.com/v4/letter/m/ea5d25/32.png) [@Mgalindo13](https://boards.straightdope.com/u/Mgalindo13)\ **Post date:** [January 3, 2012, 11:37pm UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/45 "2012-01-03T23:37:16Z")
> [@whc.03grady](#): > > The assertions of quantum physics don’t just sound weird. That’s the understatement of the year. To be told that a thing can both be something and not be something, at the same time, well, that’s a lot (a **LOT** ) weirder than being told the Earth goes around the Sun and not vice versa. Weirdness is all relative. You may not think the Earth going around the sun is weird, but not too long ago it was an absurd idea that humans weren’t the center of the universe. Similarly, pilgrims would find it ludicrous to suggest that one day man would walk on the moon. And now you find it weird that a particle can be in two states at once, despite a mountain of evidence to support that it is true. You really can’t base an objection to scientific theory on what might be considered “weird” by some people. That’s not to say that you have to accept it as true, but do some additional research, understand QM a bit more. You’ll find a lot of things that will blow your mind, the aforementioned double slit experiment is what really attracted me to the field (if only as a hobby). The overall point that you should take away from this discussion is that logical reasoning and classical physics don’t always apply in the QM world. ETA: Telemark seems to have beaten me to this point… ---
**Author:** ![whc.03grady](https://avatars.discourse-cdn.com/v4/letter/w/a6a055/32.png) [@whc.03grady](https://boards.straightdope.com/u/whc.03grady)\ **Post date:** [January 3, 2012, 11:53pm UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/46 "2012-01-03T23:53:01Z")
> [@Mgalindo13](#): > > Weirdness is all relative. You may not think the Earth going around the sun is weird, but not too long ago it was an absurd idea that humans weren’t the center of the universe. Similarly, pilgrims would find it ludicrous to suggest that one day man would walk on the moon. And now you find it weird that a particle can be in two states at once, despite a mountain of evidence to support that it is true. I hope you can see that there’s a huge, huuuuge difference between the weirdness of finding out the Earth isn’t the center of the universe (or that humans would some day walk on the moon) on the one hand, and finding out that a particle can be in two mutually-exclusive states at once on the other. But maybe I’m wrong about the mutually-exclusiveness of the states, as Omphaloskeptic suggests. Then it ain’t much weirder than anything else. ---
**Author:** ![whc.03grady](https://avatars.discourse-cdn.com/v4/letter/w/a6a055/32.png) [@whc.03grady](https://boards.straightdope.com/u/whc.03grady)\ **Post date:** [January 3, 2012, 11:59pm UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/47 "2012-01-03T23:59:30Z")
I mean, think of it this way. What if the scientific community told you, “You know, it turns out ducks are actually insects.” That’s weird. Believable, but weird. Now what if the scientific community told you, “You know, it turns out in some circumstances an object isn’t identical with itself.” That’s beyond weird. It’s something else altogether. That’s the difference I don’t think some are appreciating here. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [January 4, 2012, 12:04am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/48 "2012-01-04T00:04:38Z")
Didn’t one of the founding fathers of QM say something like “if you don’t realize the extraordinary weirdness of QM you don’t understand QM”? I’m almost sure somebody said that. ---
**Author:** ![Mgalindo13](https://avatars.discourse-cdn.com/v4/letter/m/ea5d25/32.png) [@Mgalindo13](https://boards.straightdope.com/u/Mgalindo13)\ **Post date:** [January 4, 2012, 12:05am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/49 "2012-01-04T00:05:20Z")
> [@whc.03grady](#): > > I hope you can see that there’s a huge, huuuuge difference between the weirdness of finding out the Earth isn’t the center of the universe (or that humans would some day walk on the moon) on the one hand, and finding out that a particle can be in two mutually-exclusive states at once on the other. > > Unless I’m wrong about the mutually-exclusiveness of the states, as Omphaloskeptic suggests. Then it ain’t much weirder than anything else. There’s not a difference, that’s my point. You personally may see a difference, but that’s a relative point of view. You grew up _knowing_ that the Earth was round and revolved around the sun, so it’s logical to you. For someone many years ago , it would be a completely foreign and absurd concept. Just because YOU think something is weird doesn’t make it a fallacy. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [January 4, 2012, 12:07am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/50 "2012-01-04T00:07:14Z")
I doubt a simple analogy will help resolve an issue this difficult, but I’ve heard superposition described by comparing it to spinning a coin. Heads and Tails are mutually exclusive states, but if you spin the coin on a table, it’s in a state of heads-tails superposition. You cannot simply say “the coin is either heads or tails, but we don’t know which” because that only makes sense when describing the observed outcome. There are experimental findings that back this up. Despite the affront to “common sense,” particles really are in a temporary superposition, and not just in a temporary statistical unknown. ---
**Author:** ![whc.03grady](https://avatars.discourse-cdn.com/v4/letter/w/a6a055/32.png) [@whc.03grady](https://boards.straightdope.com/u/whc.03grady)\ **Post date:** [January 4, 2012, 12:25am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/51 "2012-01-04T00:25:13Z")
> [@Mgalindo13](#): > > There’s not a difference, that’s my point. You personally may see a difference, but that’s a relative point of view. You grew up _knowing_ that the Earth was round and revolved around the sun, so it’s logical to you. For someone many years ago , it would be a completely foreign and absurd concept. > > Just because YOU think something is weird doesn’t make it a fallacy. If someone can’t see that every thing is identical with itself is true now, was true at the time of the dinosaurs, is true at the center of Mars, and is true regardless of how one is brought up, then I can’t help that person. To believe otherwise is to abandon rationality, to reject the fruits of scientific inquiry. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [January 4, 2012, 12:42am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/52 "2012-01-04T00:42:22Z")
> [@Mgalindo13](#): > > There’s not a difference, that’s my point. You personally may see a difference, but that’s a relative point of view. You grew up _knowing_ that the Earth was round and revolved around the sun, so it’s logical to you. For someone many years ago , it would be a completely foreign and absurd concept. > > Just because YOU think something is weird doesn’t make it a fallacy. > [@whc.03grady](#): > > If someone can’t see that every thing is identical with itself is true now, was true at the time of the dinosaurs, is true at the center of Mars, and is true regardless of how one is brought up, then I can’t help that person. To believe otherwise is to abandon rationality, to reject the fruits of scientific inquiry. Mgalindo is completely correct. There is no conceivable reason why the underlying workings of the very tiniest and very largest scales should have any connection at all to our understanding, our “common sense” interpretation of what happens in the middle scales we live in. You only find QM weird because you haven’t studied it, you don’t understand it, and it contradicts some simplistic and limited view of matter that is a ridiculously minor fraction of the universe. The only thing that’s weird is that we’ve been able to develop mathematics that in any way describes how the real universe works. That this mathematics doesn’t have an easy and glib translation into common English and that it doesn’t correspond to mundane reality is the most totally **expected** thing I can think of. It really is you who’s at issue here. Or rather, it really is that you are merely human that’s at issue. Humans never see the quantum world. It is what it is, without regard to any aspect of humanness. The universe is math, not culture. If you find math weird that unfortunately says more about you than it does about math. ---
**Author:** ![Mgalindo13](https://avatars.discourse-cdn.com/v4/letter/m/ea5d25/32.png) [@Mgalindo13](https://boards.straightdope.com/u/Mgalindo13)\ **Post date:** [January 4, 2012, 12:46am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/53 "2012-01-04T00:46:27Z")
> [@whc.03grady](#): > > If someone can’t see that every thing is identical with itself is true now, was true at the time of the dinosaurs, is true at the center of Mars, and is true regardless of how one is brought up, then I can’t help that person. To believe otherwise is to abandon rationality, to reject the fruits of scientific inquiry. No one asked for your help, you started this thread asking “please tell me where I’ve gone wrong.” You’re not grasping the underlying concepts of quantum mechanics and it’s not something that any number posts on an Internet message board can correct. If you’re really committed to understanding the topic there’s a bounty of information available online and if you’re the self-learning type you can even try OpenCourseWare from MIT that has some great courses/materials on quantum theory. ---
**Author:** ![Candyman74](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@Candyman74](https://boards.straightdope.com/u/Candyman74)\ **Post date:** [January 4, 2012, 1:47am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/54 "2012-01-04T01:47:45Z")
> [@whc.03grady](#): > > If someone can’t see that every thing is identical with itself is true now, was true at the time of the dinosaurs, is true at the center of Mars, and is true regardless of how one is brought up, then I can’t help that person. To believe otherwise is to abandon rationality, to reject the fruits of scientific inquiry. I think the problem here is that people have tried to explain it to you, but you just reject their attempts to explain it out of hand. All that’s left is to advise you to go read up on quantum theory, because our superficial attempts aren’t doing the trick - and we can’t teach a course in it here (well, I couldn’t anyway - I understand the concepts, not the mathematics). It’s not that you’re after help in where you’ve gone wrong; you’re after an opportunity to tell us where _we’re_ wrong. It’s kinda like the My Problems With Relativity thread, where someone thinks he’s proved Einstein wrong. He hasn’t, but he won’t accept that. In order to refute a theory, you need to understand it first. Otherwise how do you even know what it is you’re refuting? I mean, you know you’re refuting a 3-sentence description of what quantum mechanics is to you, but quantum mechanics is not a 3-sentence description; it’s a million equations, experiments, observations, and fulfilled predictions. _Those_ are what you have to refute, not a soundbyte description you heard; and to refute them, you have to understand them very well indeed. You have to intimately know the equations, what they mean, how they were derived, how they are used. Then you can point out what’s wrong with them. ---
**Author:** ![Animastryfe](https://avatars.discourse-cdn.com/v4/letter/a/8797f3/32.png) [@Animastryfe](https://boards.straightdope.com/u/Animastryfe)\ **Post date:** [January 4, 2012, 2:04am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/55 "2012-01-04T02:04:13Z")
> [@WarmNPrickly](#): > > Probably a physicist can fill in the gaps here, but when they first measured the speed of light, it was quite astounding that no matter how you measured it, you got the same number. That is not something that fit into any classical physics scheme. Ah, I understand now. I was thinking that you were referring to the numerical value of c. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [January 4, 2012, 2:19am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/56 "2012-01-04T02:19:02Z")
This is an excerpt from an English translation of S’s paper _The Present Situation in Quantum Mechanics_–which can be read in its entirety on line–where the cat first appears. It helps to get to primary sources. The intro graf helps get things going: That it is in fact not impossible to express the degree and kind of blurring of all variables in one perfectly clear concept follows at once from the fact that Q.M. as a matter of fact has and uses such an instrument, the so-called wave function or psi-function, also called system vector. Much more is to be said about it further on. That it is an abstract, unintuitive mathematical construct is a scruple that almost always surfaces against new aids to thought and that carries no great message. At all events it is an imagined entity that images the blurring of all variables at every moment just as clearly and faithfully as does the classical model its sharp numerical values. Its equation of motion too, the law of its time variation, so long as the system is left undisturbed, lags not one iota, in clarity and determinacy, behind the equations of motion of the classical model.the … Inside the nucleus, blurring doesn’t bother us. One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The _psi-function of the entire system_ would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts. [ital mine] That the lack of the excluded middle is justifiable is discuused in almost identical language by Heisenberg on page 124 of [Physics and Philosophy](http://www.naturalthinker.net/trl/texts/Heisenberg,Werner/Heisenberg,%20Werner%20-%20Physics%20and%20philosophy.pdf) (entire book online in PDF). ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [January 4, 2012, 2:31am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/57 "2012-01-04T02:31:14Z")
Post pickup after edit window cut off] > [@Leo\_Bloom](#): > > That the lack of the excluded middle is justifiable and necessary in the real world (in these contexts)–as posted above by a number of people–is discuused in almost identical language by Heisenberg on page 124 of his book [Physics and Philosophy](http://www.naturalthinker.net/trl/texts/Heisenberg,Werner/Heisenberg,%20Werner%20-%20Physics%20and%20philosophy.pdf) (the entire book is [online](http://www.naturalthinker.net/trl/texts/Heisenberg,Werner/Heisenberg,%20Werner%20-%20Physics%20and%20philosophy.pdf) in PDF). ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [January 4, 2012, 2:37am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/58 "2012-01-04T02:37:02Z")
> [@Cheesesteak](#): > > This is seriously the truth. You cannot rely on everyday logic for Quantum matters. > > A simple example is the [Double Slit Experiment](http://en.wikipedia.org/wiki/Double-slit_experiment) Scroll down to the first variation “interference of individual particles”. The experiment makes all kind of sense until you ratchet down the intensity to where you only have individual particles going through the slits at one time. At that point, they continue to show the same interference pattern, even though there isn’t any second particle/photon for it to interfere with. It makes absolutely no sense, but the effect has been known for over 100 years. It’s very surprising (or was anyway) but it’s not contrary to logic in any sense I can think of. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [January 4, 2012, 2:39am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/59 "2012-01-04T02:39:28Z")
> [@Leo\_Bloom](#): > > Post pickup after edit window cut off] I don’t think anyone in the thread has argued that excluded middle is violated by quantum phenomena, including superposition. And it’s not. 😉 ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [January 4, 2012, 4:19am UTC](https://boards.straightdope.com/t/schrodingers-cat/608260/60 "2012-01-04T04:19:22Z")
> [@Omphaloskeptic](#): > > I … > Of course what’s more likely than an inconsistency in logic is that there’s been an error in the attempt to translate from physical measurements to physical laws to logical statements; and this is what I think is wrong with your first statement. (This is especially easy to do if you’re reading popular accounts, which may not be terribly precise in their use of language.) You say that a cat must be either alive or not-alive (excluded middle), and implicitly count this as two distinct well-defined states exhausting all possibilities. At least one of these two properties is empirically shown to fail in quantum mechanics, however. The usual informal way in which physicists talk about this is to label two particular states of the cat system as “alive” and “dead” and then understand that quantum mechanics allows superpositions of these two states. Now you see that there’s not actually a logical contradiction. There are more than two possibilities, so excluded middle does not apply, and “not-alive” is not the same as “dead”. I was reading this. Did I get the wrong end of the stick? [Previous page](https://boards.straightdope.com/t/schrodingers-cat/608260.md?page=2) [Next page](https://boards.straightdope.com/t/schrodingers-cat/608260.md?page=4)