Talk:Schrödinger's cat/Archive 3

The problem with Wikipedia's science articles
Complexity. The articles are written for experts, and experts already know all this stuff. The overwhelming majority of people in the world are not experts in physics, chemistry, biology, etc.

To me (and I'm sure the majority of readers), this article is gibberish from beginning to end. You need a lot of information to understand, something most people don't have, and even if you follow the links to understand some basics, the 'basics' are just as complicated and difficult to understand.

When it comes to science articles, Wikipedia is practically useless. —Preceding unsigned comment added by PsychoticClown (talk • contribs) 12:23, 28 July 2008 (UTC)


 * While I agree that this article has been scrubbed of any simplification at the expense of authentication, I feel that most science articles in Wikipedia are readable and understandable. However, this one is definitely not written to be comprehensible by 99.9 % of the general population. The number of people in the world that actually understand the concepts of quantum mechanics has to be infinitesimal; consequently, this article might be acceptable to scholars in the field, but what happened to the egalitarian ambiance of Wikipedia?  The average Joe could not read this article and understand anything about it; consequently, he would never read about this very interesting concept.  Intellectual snobbery is alive and well.--Bill Spencer (talk) 19:26, 29 July 2008 (UTC)


 * Quantum mechanics is a notoriously difficult subject. The editorial question is whether the article is harder to follow than is strictly necessary given the topic. 1Z (talk) 19:42, 29 July 2008 (UTC)
 * Quite. Whilst we strive to make article comprehensible we must recognise that some subjects -- and this is definitely one -- are intrinsically difficult. I would venture to guess that even most physics grad students don't understand the experiment. Any confusion or complexity in the article is definitely not snobbery. --Michael C. Price talk 20:40, 29 July 2008 (UTC)
 * Appropriately, the the original comment is both right and wrong. There is a tendency for some experts to write science articles for each other, but there are also plenty of useful science articles on Wikipedia which can be understood by high school students. I don't think there are any guidelines on Wikipedia on the level of articles other than to say it's an encyclopedia -- am I right on this? It's therefore up to us. It obviously depends on the subject matter -- some topics are clearly only encountered in undergraduate or postgraduate courses. My feeling is that the lead-in paragraphs should enable a general reader with a high school education to feel informed on the scope of the article. Topics which are likely to be encountered by high school students should have general sections understandable by them with separate advanced sections going up to undergraduate level if necessary. (In some cases there may be an argument that an article could be split into separate general and specialised articles). Strayan (talk) 03:57, 8 August 2008 (UTC)

In order to be properly explained, some things just can't be simplified any further. Not everything is simple enough for the average person to understand. We have to accept that fact. We all have the right to attempt to understand things, but don't blame Wikipedia for your lack of ability to grasp a concept. It's not the teacher, it's you. You're just not smart enough. Neither are most other people (including myself). And of the people that claim to understand, most of those probably understand the least because they don't even know enough to grasp the full complexity of the experiment. Then there is the small minority that do fully understand. You likely don't know any of those people. They're rare. Like lightning strike victims. —Preceding unsigned comment added by 206.186.240.194 (talk) 14:47, 20 November 2008 (UTC)

Fuck off, faggot, I understand this completely.

Original research (August 2008)
Please read the last few lines of the section "The thought experiment": Note that no charge of gunpowder is mentioned in Schrödinger's set-up, which uses a Geiger counter as an amplifier and poison instead of gunpowder; Einstein was probably thinking of his keg of gunpowder suggestion. When I see the words "probably" or "one can only come to the conclusion" or "what they meant was", and I don't see a valid citation sourcing the statement, it leads me to believe that the statement was written by an editor, which makes it original research by definition. While the conclusion may or may not be correct, it is not up to Wikipedia to draw a conclusion for its readers. Wikipedia simply presents the facts, which then allows readers to draw their own conclusions based on the facts. "Note that no charge of gunpowder..." is a fact, pointed out to allow the reader to come to a conclusion about what Einstein meant. "Einstein was probably thinking of..." is a conclusion based on the idea that someone knows what Einstein was thinking, which, without a cited source, does not belong in Wikipedia. — OranL (talk) 17:29, 5 August 2008 (UTC)
 * But my point was that this wasn't a conclusion; hence the word probably. Would you be happier with the phrase it is possible?  I really think that without some pointer to a possible solution that readers can get confused here.  Or would you be happier with a double note paragraph?

Note that no charge of gunpowder is mentioned in Schrödinger's set-up, which uses a Geiger counter as an amplifier and poison instead of gunpowder; and note that Einstein had originally referred to a keg of gunpowder in his suggestion to Schrodinger 15 years ago.


 * It seems a horribly contrived structure. --Michael C. Price talk 18:13, 5 August 2008 (UTC)
 * In my opinion, the whole statement should be removed, starting from "Note that no charge..." to "...his keg of gunpowder suggestion." The explanation is not necessary, because it is pointing out a minor flaw in Einstein's text. The point of this section is to show that Einstein agreeed with Schrodinger's thought experiment, and the fact that Einstein included the wrong apparatus in his agreement is trivial at best. The only source I could find that even comes close to pointing out the fact that Einstein might have written the wrong thing by accident is this blog, where the author adds "[release of hydroacid]" before "charge of gunpowder". All in all, the statement "Note that no charge..." serves only to point out something that is not relevant to the current topic, and in my opinion should be removed. — OranL (talk) 19:19, 5 August 2008 (UTC)


 * This is an important quote with a trivial error, and it is perfectly reasonable to point out that error in a note, properly qualified by 'perhaps', to make it more comprehensible to readers. I don't think that is 'independent research'.   The correspondence doesn't make much sense without assuming the 'gunpowder' reference is an error.  Besides, the reference OranL found supports it, so it is no longer unsupported.  This topic is confusing enough without further baffling readers with trivial errors.  I think it should be left as it is.  -- Chetvorno TALK CONTRIB   20:06, 5 August 2008 (UTC)


 * The more I read the statement, the more I don't like it. The statement is pointing out that Einstein made a mistake. There is no purpose for this, as far as I can see, other than to say "Hey look! Einstein made a mistake!" When editors of other non-biased publications want to correct an error or omission in a direct quote, they use brackets to insert what is generally assumed to be the intention of the quoted source. If you are adamant about pointing out this mistake, I suggest removing the statement after the quote and changing the quote to look like the blog entry's quote or to look like this:

Their interpretation is, however, refuted most elegantly by your system of radioactive atom + amplifier + charge of gun powder [cyanide] + cat in a box, in which the psi-function of the system contains both the cat alive and blown to bits [poisoned].
 * Either way, I suggest you do not cite the blog entry as a source for Einstein's assumed meaning, because no one will accept it as a valid source. — OranL (talk) 20:48, 5 August 2008 (UTC)
 * The statement is pointing out that Einstein made a mistake. There is no purpose for this, as far as I can see, other than to say "Hey look! Einstein made a mistake!" Actually I don't regard it as a mistake by Einstein, just that he was referring to his original conception of the experiment.  As for the purpose, I would have thought that is obvious.  The statement shows the high regard in which Einstein held the experiment, but it necessary to explain the reader why he referred to gunpowder, even though there is no reference to gunpowder in Schrodinger's paper. Simply putting the "corrected" quote in []s is not self-explanatory the general reader.
 * The point Chetvorno makes about needing absolute clarity in the article is well made, as a glance at the history of the article demonstrates.--Michael C. Price talk 05:58, 6 August 2008 (UTC)
 * This discussion has been listed on No original research/noticeboard.


 * Personally, I wouldn't change the quote, because I would trust the reader enough to allow them to figure out that Einstein was referring to something other than Schrodinger's experiment, but if I was to change the quote, I would put it like this: "Their interpretation is, however, refuted most elegantly by your system of radioactive atom + amplifier + [cyanide] + cat in a box, in which the psi-function of the system contains both the cat alive and [dead]."
 * The fact that you don't believe that Einstein made a mistake, while I do, shows the ambiguity of the quote and the need for a valid reference for any statement that tries to explain what he meant. The quote itself is showing how highly Einstein regarded the Schrodinger thought experiment, so another statement after that would be unnecessary. Finally, brackets are frequently used by mainstream publishers when quoting material. I think you aren't giving the reader enough credit. [[Image:smiley.png|15px]] — OranL (talk) 16:50, 6 August 2008 (UTC)
 * You may think these things are self-explanatory but I can assure you the past history shows that virtually nothing about S's cat is self-evident and everything must be explained in great and painful detail. BTW I don't approve of changing quotes -- surely that is an even more egregious example of OR, especially as it seems there is no such published interpretation of the Einstein quote.  What you are suggesting is more OR than the current text, since your interpretation is blandly presented as fact, whereas at least the current text has a conditional "perhaps" in place. --Michael C. Price talk 17:07, 6 August 2008 (UTC)


 * WP:NOTOR supports the use of square bracket corrections in quotes only for typographical or proofing errors, which this isn't. The last section on that page, 'Caveats about expert material' makes clear that raising questions about contradictions or errors in expert material is not OR, and suggests addressing the contradiction with a note in the text, as has been done here.  -- Chetvorno TALK 20:48, 6 August 2008 (UTC)
 * While it is both logical and reasonable to assume that Einstein probably made a mistake... to actually say so requires a third party source. I would be very very suprised to discover that Wikipedia is the first to mention it (and if it is, then mentioning it is OR).  Blueboar (talk) 00:15, 7 August 2008 (UTC)

I've quickly read the section in question and find this debate rather a waste of everyone's time. The material that has generated this discussion is perfectly reasonable. I'm sure the article could be improved, but this point you are debating certainly doesn't contribute. If you all simply must resolve the matter through some sort of compromise, why not simply paraphrase the quote and skirt the part you can't agree on? I don't think it's essence would be thereby lost and the use of block quotes, in any case, is generally inelegant writing. Calamitybrook (talk) 01:54, 7 August 2008 (UTC)


 * You have a great idea. What if the section was rewritten to look like this (note this is just a drafted idea, feel free to change it if I am missing something):

Each alternative seemed absurd to Albert Einstein, who was impressed by the ability of the thought experiment to highlight these issues; in a letter dated 1950, he praised Schrödinger for the experiment's elegant refutation of what he called a "risky game…with reality" on the part of most other contemporary physicists. He wrote that Schrödinger and Laue are the only ones "who [see] that one cannot get around the assumption of reality—if only one is honest" and "[n]obody really doubts that the presence or absence of the cat is something independent of the act of observation." — OranL (talk) 03:45, 7 August 2008 (UTC)


 * I feel this quote is one of the best things in the article. Einstein's objection to the paradoxical nature of quantum superpositions - in the urgency of his own words - is an important part of the history of quantum mechanics.  I would object very strongly to it being eviscerated by paraphrasing or any other tampering. -- Chetvorno TALK 04:36, 7 August 2008 (UTC)
 * I agree that the quote is too important to be eviscerated. Let it stand as it is, for heavens sake.  As for the issue of whether Einstein made a mistake or not -- how irrelevant; the article does not say he made a mistake, please everyone stopping bringing the issue up for gawd's sake. --Michael C. Price talk 07:32, 7 August 2008 (UTC)
 * Consulting WP:NOTOR and common sense, here's how I see it:
 * It is clearly acceptable to amend an error in the original text by making some kind of note, as Chetvorno stated above. "Wikipedians are not mere copyists."  Pointing out an obvious error in Einstein's text is not OR in any way.
 * I disagree with Chetvorno that a [sic] should only be placed in the event of a typographical or grammatical error. The NOTOR essay recommends a [sic] in these instances, but does not limit or proscribe its use in any way.  [sic] is a textual note, and can be used for any textual abnormality as a way of making clear to the reader that the original text does indeed read in such a manner, as well as alerting the reader to a possible discrepancy or error.
 * I agree that there is a WEIGHT issue with having a two-sentence note on this minor issue.
 * I agree that paraphrasing this interesting quote is sub-optimal and should be avoided.
 * Therefore, I suggest that we address this minor textual error with the insertion of a minor textual note, a [sic] insertion after the "charge of gun-powder" phrase. This is the simplest and best solution.  Mr. IP  《 Defender of Open Editing 》 17:41, 8 August 2008 (UTC)
 * I have already amended the "note" so that there is no whiff of OR around it. --Michael C. Price talk 17:42, 9 August 2008 (UTC)
 * Looks good to me, MCP!  Mr. IP  《 Defender of Open Editing 》 20:41, 9 August 2008 (UTC)

Please add to "In Popular Culture"
In TV show Stargate: SG1, the physicist character names her cat Schrodinger. Fry-kun (talk) 02:34, 19 September 2008 (UTC)

Interesting video
I came across an interesting video on this subject, which explains it n a very easy to understand way, perhaps it should be included in the external links?



Alecjw (talk) 13:33, 5 June 2009 (UTC)

Getting bogged down in semantics
Though I am more polymath than specialist, the individual obsessed with the "Transitional State" concept is starting to get to me. As well argue as to the colour of the cat's coat. Please correct me if I am wrong, but unless my explanation is being muddled by over-simplification, the whole thought experiment is a rhetorical question intended to point out that, whatever the state of the cat, dog, horse, zebra, emu, or baby brother within the opaque container, the two (or three, if I have misjudged the validity of a Transitional State) possible end conditions cannot simultaneously exist, as the idea of a cat that is simultaneously alive and dead, which, as clearly stated by the quote of the thought experiment, cannot be in a single reality. A thing is either alive or it is not. This poses a problem, but only for Copenhagenists. Unless, again, I am undone by oversimplification, the cat that adheres to the Many Worlds Interpretation would exist in all states, each in its own dimension. The whole thought experiment is designed to point out the folly of the Copenhagenist Interpretation, in that it accords not at all with the reality we inhabit. The summation, at least, or the introduction, should contain the observation that its author intended it as a reductio ad absurdium to illustrate the weakness of the Copenhagenist Interpretation of QM. Again, unless I'm mistaken, this thought experiment is no more than a simple analogy cloaked in the form of a scientific experiment; the cat is either alive or dead, and cannot be both simultaneously in the reality in which we exist, operate, and experiment. It's not about the cat, but about the existence of multiple simultaneous states, which is difficult, if not impossible, to reconcile with the Copenhagenist Interpretation, and that Many Worlds ties up, if not succinctly, then at least neatly enough for laymen grasp. 99.233.29.111 (talk) 08:31, 9 July 2009 (UTC)


 * The article makes it clear that Schro's thought experiment was a reductio ad absurdum critique of the Copenhagen interpretation: Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility, quite the reverse.... -- Chetvorno TALK 10:59, 9 July 2009 (UTC)

Location of Article
Why was this page moved from "Schrödinger's Cat" to "Schrödinger's Cats"? It seems to me that this is some kind of mistake or bad decision and it should be reverted. I don't know how to do that though so if anyone knows how to and agrees with me please do it. For the time being I've fixed the redirect placed on "Schrödinger's Cat" to actually redirect to this article. —Preceding unsigned comment added by Eblingdp (talk • contribs) 20:19, 10 July 2009 (UTC)
 * It needs an admin (AFAIK), because the redirect page has to be got rid of first. I've requested this. --Old Moonraker (talk) 20:22, 10 July 2009 (UTC)
 * Fixed. Thanks User:Bubba hotep. --Old Moonraker (talk) 06:25, 12 July 2009 (UTC)

Better Overview?
I believe the following, taken from http://whatis.techtarget.com/definition/0,,sid9_gci341236,00.html, serves as a much better summary of the subject: Schrödinger's cat is a famous illustration of the principle in quantum theory of superposition, proposed by Erwin Schrödinger in 1935. Schrödinger's cat serves to demonstrate the apparent conflict between what quantum theory tells us is true about the nature and behavior of matter on the microscopic level and what we observe to be true about the nature and behavior of matter on the macroscopic level.

Perhaps something similar can be written here. —Preceding unsigned comment added by 146.232.65.6 (talk) 21:29, 20 September 2007 (UTC)

You have a ignorant understanding of quantum theory. 203.59.213.54 (talk) 05:34, 14 August 2009 (UTC) Harlequin

Yikes! We’ve been Wikipedia-ed!!!
Well, let’s count our positives. We have a great picture of a real live cat. . .  meow. . .  meow. We have a great picture of a cartoon cat, who is simultaneously both alive and dead (the superposition!). We have a good quote by Erwin Schrodinger, and another by Steven Weinberg. And we have a lot of good writing.

Now, we are a little bit too formal, a little bit too much emphasis on including words in blue. But, that goes with the territory, that’s kind of the wikipedia disease. In point of fact, we are much better than average. We don’t really need to take much if anything out. We just need to add some good, clear English description when appropriate. Every so often, just give yourself permission to write with a little verve. Communicate with me as clearly as if I were sitting across the table from you.

And now, someone goes and archives our discussion (still very much there, but in an archive, kind of the psychological, human-interactional equivalent of superposition!). And we are told, “This is not a forum for general discussion of views on Schrodinger’s cat. . .  ”  Hmphh! Fiddlesticks! Horse manure!!! So, what are we, a religion, is that it? Oh, no, we can’t think for ourselves, we can’t question the received wisdom, all we can do is, what, wordsmith the article? (And the comparison is actually unfair to religion! Most mature religions advocate both faith and reason, although in a fashion that kind of stacks the deck, in my opinion, that is, in my opinion.  Other people might see it differently, and that’s perfectly fine.)  So, anyway, in an article on Schrodinger’s Cat, I feel that it is reasonable and realistic to discuss. . .  Schrodinger’s Cat! And we can discuss quantum physics, and physics in general. Now, if the discussion branches far afield, say that graduate programs are unnecessarily restrictive, and we find that we’re really spending a lot of time on that, well, we can address that situation when it comes up.

The “rule” is anticipating a problem that will only occasionally be present. Yes, it is possible that a discussion might go far afield. Discussions have a way of doing that. So, if and when that happens, we can gently guide it back on track.

I think we have had a very good discussion. And if only 10%, or less, of it finds its way into the article, or if it merely helps the people writing the article to see what the rest of us understand and don’t understand, that’s all for the good.

So, what I recommend is that bit by bit we move our previous discussion back here, and in the process refresh it. That is, we turn a potentially negative situation into a positive. And at the same time, we remain very, very open to new discussion.

I will take the first step. I’m taking my piece previously entitled, “All interpretations, including Copenhagen, take one step beyond current science?” and moving it back here, and including a longer version of the quote. And I do wish to apologize for previously getting the page number wrong. The quote is from Dan Hooper’s DARK COSMOS. The correct page number is 58.

Happy thinking, everyone! And happy writing! FriendlyRiverOtter 22:11, 1 June 2007 (UTC)
 * This really isn't a page for general discussion of quantum mechanics; there are better places for that, where you won't make it more difficult for editors to improve the article. See the talk page guidelines for more information. I really will start deleting discussions if they continue here. Maybe try starting discussions in the science part of WP:RD or something if you want to keep the discussions inside Wikipedia. --Philosophus T 04:55, 2 June 2007 (UTC)


 * I ask that you please not delete my contributions, nor the contributions of anyone else who is sincerely trying.  FriendlyRiverOtter 03:30, 4 June 2007 (UTC)
 * What are you trying? How does it benefit the project? You are sincerely trying, but that doesn't mean that the contributions are useful. I apologize for my exasperated tone about this, but I've met far too many people in the general public who, after learning my profession, try to discuss these topics with me with the assumption that they understand the topics. In general, such people try to ponder the physics just from the knowledge they have learned from popular descriptions, without knowing the actual theories and math, and as a result their conception is so distorted that they are nearly irredeemable. --Philosophus T 07:00, 4 June 2007 (UTC)
 * If "wikipedia discussion page for Schrodinger s cat" is not a correct place to discuss on Schrodinger s cat, I can understand that. But could we be directed to some serious forum dedicated to that? Thanks. Pascal. 28 July 2009 —Preceding unsigned comment added by 87.231.105.167 (talk) 21:52, 28 July 2009 (UTC)

Keep it simple
This is a great article, unfortunately, some people are getting confused by it. Those with minds understand the confusion, but that's not relivent. As such, to comply better with Wikipedia, I think it would be best if it was simplified. As such, the article would not try to explain how the thought experiment works, rather just what it is (i.e. an argument between physicists). Schrödinger's explanation should still be in there, but no other. That way if people get confused, they can only blame Schrödinger and not the article. If readers want to know more, they can follow the links about quantum mechanics and such. Furthermore, this article is a great start for a more in depth study that should be on Wikiversity.--98.182.28.191 (talk) 21:47, 13 August 2009 (UTC)

Error in interpretting the meaning of observation
When Schrödinger says, "If one of the atoms decays, the counter tube discharges and through a relay ...." This is nothing but observation!

... And when I say this they tend to remind me that Schrödinger was a great physicist and I'm not!!! OK, I am not a physicist at all but have a good understanding of what scientific reasoning is and how and how not a thought experiment be considered a paradox or scientific discovery or non conclusive.

People go great lengths discussing it like "... what happens when the first observer tells the second observer before the later opens the box...". Are you kidding me!! Observation in quantum physics is not equal to human sight and hearing, not even close. Quantum superposition and observation leading to a random state (as per the probability) is a valid concept, but here observation is not what it is interpreted my most, and I am sorry to say, not even by Schrödinger himself... at least not in this thought experiment. --Vinnie (talk) 07:20, 16 October 2009 (UTC)

confused
What color was the cat? —Preceding unsigned comment added by 65.167.146.130 (talk) 21:29, 17 February 2009 (UTC)
 * This is not relevant to the article--Jakebathman (talk) 02:42, 28 February 2009 (UTC)


 * Perhaps black, so one can't be sure in the dark box if the cat is walking alive or lying dead. —Preceding unsigned comment added by VinnieCool (talk • contribs) 07:07, 16 October 2009 (UTC)

Abuse of Animals!
$$\frac{1}{\sqrt{2}}|Alive\rang + \frac{1}{\sqrt{2}}|Dead\rang = |Cruelty\rang$$

How can you calmly accept a 50% chance of a murdered cat??!!! This is butchery! Remember: Quantum decoherence is murder! - Survivors of Schrödinger 65.96.201.130 (talk) 04:01, 8 March 2009 (UTC)


 * Perhaps Hugh Everett III can give you comfort. Eeekster (talk) 04:06, 8 March 2009 (UTC)


 * That's certainly no excuse! One universe with a dead cat is one universe too many. Stop the madness! 65.96.201.130 (talk) 04:13, 8 March 2009 (UTC)


 * Personally, I'd be more worried that when they opened the box, the cat would still be simultaneously dead and alive, which in turn could be the trigger for a major disaster should it escape... Wardog (talk) 14:35, 23 March 2009 (UTC)

Would it be useful to consider a transition state for the cat? Since death by exposure to hydrocyanic acid will involve a measurable time interval, for the sake of this discussion, let’s assume it will take 30 seconds for the cat to perish. If a light on the outside of the box is illuminated at the same instant the relay releases the hammer (to alert an observer) and precisely 15 seconds later a small, opaque cover is opened exposing a small glass window, an observer looking through this window could view the subject cat in a state transitioning from live to dead. At that instant, the cat would be half alive and half dead. Comments? —Preceding unsigned comment added by 68.157.140.49 (talk) 01:28, 15 May 2009 (UTC)

One thing that enrages is me is it's always a cat in these type of expeirements. Oh sure, like it's even worse to kill a dog or rabbit. --141.158.180.49 (talk) 18:20, 16 May 2009 (UTC)

To minimize objections by animal rights types, I recommend replacing the cat with a rat. The thought experiment would then be called "Schrödinger's rat"; perhaps a more acceptable alternative for everyone. Will someone modify the main text and diagram accordingly? —Preceding unsigned comment added by 68.190.44.127 (talk) 22:06, 6 September 2009 (UTC)

As far as I know, no one has bothered to actually do the experiment. There is no need as the thing on it's own is quite enough to understand the point. 79.78.76.72 (talk) 21:14, 12 October 2009 (UTC)

Why bother?
Science isn't democratic, it's the best explanation is better than the next best. Or survival of the fittest, if you like. Why not give Schrödinger's explanation, and reference to others? What's the point of people rushing to beliefs about an article meant to be informative. I don't believe this is a correct interpretation of quantum theory, but then again, I don't believe in huge amounts of crap either. —Preceding unsigned comment added by 91.152.238.199 (talk) 23:44, 3 November 2009 (UTC)

Confusing the Masses
Would it be possible to dumb the content of this article down? While I comprehend it in its current state, I fear, as an encyclopedia entry, it's inaccessible to the vast majority of people who read it. --K10wnsta (talk) 21:46, 20 November 2009 (UTC)
 * That's not easy without it seeming pointless. But perhaps an "outline" section could be added. --Michael C. Price talk 22:13, 20 November 2009 (UTC)


 * I tried writing a more elementary introduction for the article, you can see it at User:Chetvorno/work4. I don't want it used because it isn't up to the standards of the rest of the article; I don't have the expertise of someone like Michael.  But maybe it would give someone some ideas.  I'd be interested in any comments, please leave them on my talk page. -- Chetvorno TALK 23:48, 20 November 2009 (UTC)


 * I like your version. The problem is how to incorporate it here (which is why I'm commenting here). We could put it all into its own section here and then remove any obvious overlap from the rest of the article (e.g. not have two diagrams).--Michael C. Price talk 04:32, 21 November 2009 (UTC)


 * The problem I see is that it encourages the reader to apply common sense to qm. I don't think that is good, even on first aquaintance.  It also shares problems I mentioned in my previous entry.David R. Ingham (talk) 16:45, 3 December 2009 (UTC)


 * The question, a bit more generally, is "How does one go from a quantum description to a classical one? And more specifically "What time, if any is associated with the change from one description to the other?" The article should say, early on, that he did not believe that nature ever really is classical.  This leads to his position that there is no harm in putting off the (complete) transition from qm to intuition, as long as one doesn't loose track of the quantum information in the mean time.  A clear qm result is always good, but intuition and classical physics have to be used with caution.David R. Ingham (talk) 17:09, 3 December 2009 (UTC)

So let me get this straight
The Schrödinger's cat thought experiment is just a simplification of quantum mechanics in an attempt to "point out" the absurdity of it, even though the thought experiment is ignorant of how quantum mechanics works and thus must simplify it to ridiculously concepts in order to convey that absurdity. Making the entire thing pointless in relation to quantum mechanics in the first place and NOT a serious flaw in how quantum mechanics is theorised.

Well why didn't you say so! 203.59.213.54 (talk) 02:32, 14 August 2009 (UTC) Sutter Cane


 * Thanks goodness the article is better written than your contribution. --Michael C. Price talk 08:29, 14 August 2009 (UTC)

Ah, another person who insists the thought experiments pathetic simplifications and ignorance should be pushed as "viable" regardless of how quantum mechanics works or people like sad little Michael here can understand. 203.171.196.1 (talk) 13:40, 25 August 2009 (UTC) Harlequin

I suggest you read and digest thought experiment. --Michael C. Price talk 15:56, 25 August 2009 (UTC)

This is a widely accepted part of quantum mechanics, there are thousands of people more qualified than yourself that have taken into account this problem. VincentCalci (talk) 00:07, 26 March 2010 (UTC)

Dismissing everything contradicting the basis for the simplified thought experiment isn't "taking into account this problem", nor would they be "more qualified" if they intentionally ignored contradicting problems when addressing (ie: agreeing with, which is not addressing) the thought experiment. But I suppose that ridiculous fallacy you just spewed should be expected from someone who ignores the Shrodinger cat fallacy.

The cat is not alive AND dead. It is alive OR dead. That something hasn't been observed does not make both possibilities true. This applies for quantum mechanics also. However quantum mechanics relies on accepting both are true in theorising, since changes are spontanious and it would be completely futile in practice to establish theory for only one outcome when both are possible. That is feasibility only and has no bearing on the science of quantum mechanics. It is the application, not the science itself. It would be like complaining about pencils and making a ridiculous fallacy regarding them because a scientific experiment was written down using them. Try again. 124.169.119.39 (talk) 10:38, 26 September 2011 (UTC) Sutter Cane

Purpose of Talk Page
I thought the purpose of a Talk Page was to discuss the accuracy and scope of the article, not enter into debate onto the implications (logical or otherwise) of the subject or a person's own understanding of the subject, areas which are more suited to one of the many messageboards on the web, rather than in an encyclopaedic work such as Wikipedia? --JohnArmagh (talk) 08:22, 28 August 2009 (UTC)

Off the track again
Coming back to this article after some time, I see again what I am quite sure is a different point of view about qm than Schrodinger's. I have been reading the 1935 article (in the English translation that is linked in this article) even more carefully than I did the first time through.

First, the cat is discussed early in the long article, so one should assume that it is not intended to be one of its subtler parts, that he did not intend the cat to solve the measurement problem single handed. All that the reader is expected to gather from it on the first reading is that qm at least appears to lead to the "absurd". Of course it also supports what he says later on.

As mentioned in the The Feynman Lectures on Physics, Schrodinger and Heisenberg were the first to accept that the real world is quantum mechanical and not classical at all--that classical physics must be reduced to the status of an approximation to qm. One can conjecture that this was each of their intentions, even before they arrived at the actual mathematical form of the theory. Physicists are that egotistical!

I therefore disagree with, for example "Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; quite the reverse." He believed, I think correctly, that he had re-defined the world and that everything had possible quantum mechanical descriptions, some of which could be found and some of which had useful classical approximations.

To go on with what he said later on in the article, a qm experiment always requires a classical result, that can be written down, from some sort of qm system. So at some point one must always go from a qm description to a classical one (which always involves classical approximations}. So one must find cases in which the qm and classical descriptions meet, and preferably overlap.  So there is nothing wrong with a partial quantum description of a cat, except that it is not useful in this case.

On to EPR, it seems that a similar absurd description of the EPR paradox is useful, in that it avoids the non-locality or loss of local "reality". So perhaps the half dead cat is to harden us, to prepare us for the realization that the world we think we know is only a crude approximation of the real physical world. David R. Ingham (talk) 17:15, 3 December 2009 (UTC)

Finishing the article, he doesn't actually make the claim of solving the EPR paradox, even though he has outlined the framework for an answer and pointed out difficulties with other approaches. He ends on another negative note, followed by speculations about field theory.David R. Ingham (talk) 17:59, 3 December 2009 (UTC)

He Calls the Copenhagen Interpretation what is translated as "the reigning doctrine" and "the official teaching". He disagrees with the idea that wave function collapse must be treated as a fundamentally different process from the usual smooth development, and instead says: "in the realism point of view observation is a natural process like any other and cannot per se bring about an interruption of the orderly flow of natural events." For "wave function collapse", he substitutes "through embedment in a combined catalog [wave function] for instrument and object."

So he disagrees with the Copenhagen Interpretation by being farther from intuition, not closer as this article seems to suggest. This leads to a program of gradually including more in the qm and less in the intuition, in order to broaden the scope of experiment, and now days even potential direct applications. So his point of view is not only preserves local reality, but also has proven extremely practical. David R. Ingham (talk) 21:24, 3 December 2009 (UTC)


 * I appreciate the edits and certainly don't object to changes being made. A couple of thoughts though ... when you change "highlighted" to "pointed out a philosophical problem with" (the strange nature ...) this is suggesting to me that there is a fundamental problem with the theory, i.e., that it doesn't "work" ... I know you're not suggesting this but the prior text reads more like "strange but true" and your text suggests (to me) "strange and inconsistent".  Similarly when you change to "the problem was with the Copenhagen ..." the word "problem" is loaded, especially to a casual reader, it suggests something isn't working ... I know you're not suggesting the concepts/theory is broken but the edits start to set that as a tone.  Your line about "subtle mockery" sounds too much like synthesis to me and your making such a point which, true or not, really requires a reliable external source reference.  I don't mean to come off as critical, it is admirable that you're working hard on improving the article and admirable that you are being bold in doing so. BobKawanaka (talk) 16:00, 4 December 2009 (UTC)

I realize that I reversed the meaning of this section in one edit. Perhaps I didn't wait long enough for a reply, before going ahead. I think I did say enough here to justify the edit.

There is a problem with the Copenhagen Interpretation. People call it something like "local realism" or "spooky nonlocality". See the Weinberg quote in the Copenhagen interpretation article and other material on Wikipedia. The problem need not be fatal, but there is a better way which is to take the "Interpretation" as a rule of thumb, for which it has adequate philosophical justification, but keep the equations as the fundamental physics and fall back to them where the Interpretation doesn't apply. It does work for what it was intended for, but it isn't basic physics. Not everyone agrees with all of this but it is exactly what the article says, which is what we need here. The article is a bit hard to read, but it does say all of this directly.

The other problem is the Copenhagen Interpretation's dependence on a conscious observer to define an experiment. Maybe it can be formulated to get around this, but it at least appears to be very odd for a law of physics. As to "subtle mockery", I am quite sure that is what he intended because I already read it that way before my last reading of the article and other people's discussion of the subject. I can't insist on the strong language. If other editors don't see that in the article itself, perhaps it does need a reference. I think it adds a lot to the article, which is about the literary and pedagogical as well as the scientific and philosophical value of the cat. So I hope others will keep their eyes open to help find a reference. In the mean time, would others be willing to leave in something like that as a conjecture? We really do need something that sheds light on why he used a cat, rather than a brick, for the example. If he wanted to emphasize the large size, he would have used a house or an elephant. The special thing about a cat is that we are not sure whether it is conscious or not. So it must be a reference to the Interpretation's dependence on a conscious observer. Probably, that wasn't included in Einstein's gun powder version because E. thought the problem was in S's equation.

As the name of the thread implies, I worked on this article once before when it was missing Schrödinger's meaning, but it drifted back. So I have been careful this time to justify what I am doing and to present a clear picture of what was going on then, that has made the cat famous. David R. Ingham (talk) 18:25, 4 December 2009 (UTC)

I am no longer convinced that I know what he meant by using a cat as his example, and I haven't found anything that illuminates it. I still think it is a very interesting question. It does seem that it turned out to be a bad choice, because it allowed people to dismiss the whole example as irony, while he actually meant it exactly as he said it.

I am thinking I did the right thing by making my post to the article when I did, because if your (or y'all as my wife would say) were too busy to work on the article now, at least it was a clear improvement over what was there, and if you were ready to work on the article you needed to have your attention called to the severity of the problem, which you might not notice quickly from my lengthy posts here.

I mentioned that I didn't actually find a claim in the article that he had fixed the problem Einstein, et. al. pointed out, but that no longer bothers me because it is obvious that if one sticks to the mathematics, one won't have philosophical problems, only disagreements with observation and math errors. It is largely a review article but the part that was original, or at least not well known, is his start on the program that Weinberg mentions to derive the "usual probabilistic rules" from the mathematics without additional physical assumptions like wave function collapse. To the extent that his discussion of measurement was credible, the problem was clearly solved without further discussion.David R. Ingham (talk) 19:07, 5 December 2009 (UTC)


 * I will read your comments more thoroughly in a while and try to give a considered response. I disagree that there is a "problem" with the Copenhagen Intrepretation ... people may have trouble reconciling it with their "common sense" interpretations of the real world but when we start throwing words like "problem" around it suggests that Quantum Mechanics itself doesn't work which is clearly not the case.  We may have a problem figuring out how things happen in Quantum Mechanics (spooky action at a distance) etc. but so far, these principles have continued to pass scientific experimental scrutiny, so the only "problems" are the issues people have with making the ideas of the theory consistent with their everyday experience ... while there may be a level of discomfort with the philosophical issues, this is different from the scientific issues of the theory. I would also say that it is Original Reseach and Synthesis for this article to determine what his mindset was or what his goal was in setting the example.  If there are sources that have an opinion on that we can quote them and particular quotes from his own writing can be used, but this article should state his quotes on their own, and be careful not to deduce/synthesize/read-between-the lines what those quotes mean or suggest. BobKawanaka (talk) 22:48, 5 December 2009 (UTC)


 * I agree with BobKawanaka in general. The "problems" with the CI are dealt with in the Interpretations section. -- Chetvorno TALK 23:17, 5 December 2009 (UTC)

About there being a problem, see the Steven Weinberg quote in the objections section of the Copenhagen interpretation article. Also the article itself discusses philosophical problems with "the reigning doctrine".

I found where he refers to the cat later on: ''As to the instrument the catalog is far from complete, telling us nothing at all about where the recording pen left its trace. (Remember that poisoned cat!)'' He means that, just like the cat, the instrument has no unique classical description. By far from complete he means that the instrument is still entangled with the system being measured.

Than you for your attention.David R. Ingham (talk) 02:35, 6 December 2009 (UTC)

As to sources, the main question is whether an original physics research paper is a reasonable source for an encyclopedia. There is also the question of whether anyone else has the time and experience to read it, or at least the quotes I have put here. In any case we can't leave this article saying the opposite of what he says in that article. I am still looking for other sources but I don't know what I will find. The paper seems to have had much less effect than it should have, perhaps due to the politics of the time. In the worst case we could settle on saying that opinions differ on whether the cat was meant literally or as irony. David R. Ingham (talk) 03:02, 6 December 2009 (UTC)

"it suggests that Quantum Mechanics itself doesn't work": I mean the contrary to that. It work better than most people and a lot of physicists know. Much better than most physicists expected in the 1930s. That is what is really so special about this "cat" article.

"The 'problems' with the CI are dealt with in the Interpretations section." Yes, I have reffered above to a quote there. But we need to explain the context of the cat and agree whether it(he?) was meant in jest or literally, or at least say we don't agree. David R. Ingham (talk) 05:49, 6 December 2009 (UTC) David R. Ingham (talk) 05:49, 6 December 2009 (UTC)

I left a short note on the qm talk page asking for help on this issue. David R. Ingham (talk) 06:50, 6 December 2009 (UTC)

For the time being, why don't we just omit the sentence "Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; quite the reverse." that I originally complained about? David R. Ingham (talk) 06:54, 6 December 2009 (UTC)
 * Re your last point, because the sentence is cruical. The whole point of the thought experiment, to Schrodinger, was that dead-and-alive cats were not possible.  If you don't get that, you don't get the whole point.  Ergo the sentence must stay. --Michael C. Price talk 11:01, 6 December 2009 (UTC)

I think it is very important to call attention to this disagreement, both inside and outside Wikipedia. As I said in an edit summary, my conclusions from the original research article directly oppose conclusions that may be based on secondary sources. If there are indeed errors in secondary sources, we have an unusual opportunity here to point them out to the general physics community. David R. Ingham (talk) 20:19, 6 December 2009 (UTC)
 * Your original research conclusions are irrelevant to Wikipedia (and common sense). --Michael C. Price talk 20:28, 6 December 2009 (UTC)

The subject of the article can't be irrelevant to the article. David R. Ingham (talk) 22:19, 6 December 2009 (UTC)

The translation linked does say "ridiculous", but he can't have meant the whole article to be a spoof. Look how he refers to it later, as I quoted above. Do you know where to find it in German? David R. Ingham (talk) 23:03, 6 December 2009 (UTC)


 * I don't know how you you can be so far off beam on this, but I really don't care to waste my time debating something that is: 1) obvious 2) sourced 3) universally accepted. --Michael C. Price talk 23:09, 6 December 2009 (UTC)
 * PS have a look at the Einstein letter. Einstein and Schrodinger understood each other perfectly: "Nobody really doubts that the presence or absence of the [alive] cat is something independent of the act of observation." --Michael C. Price talk 00:17, 7 December 2009 (UTC)

I thank you again, Michael, for finally convincing me that the reading here is the usual one and this is not the place to discuss it further. The reason that I thank you is that you have shown me that I have found something more important than I had realized. I do ask that the banners should be left on the article for a while though, because my objections are well founded. They just can't be answered here. David R. Ingham (talk) 01:08, 7 December 2009 (UTC)

Can anyone make this page a little more understandable? It's just too filled with sciency words that most people don't know. How bout a simple "The cat is both alive and dead"? Is that so hard? —Preceding unsigned comment added by 96.244.229.223 (talk) 10:10, 18 March 2010 (UTC)

Schrödinger's silly question
The article says, quite correctly in my opinion, the following:

"Schrödinger's famous thought experiment poses the question, when does a quantum system stop existing as a mixture of states and become one or the other?"

This is exactly the same as saying:

"Schrödinger's famous thought experiment poses the question, when does a quantum system stop existing as one or the other and become one or the other?"

The two uses of the phrase "one or the other" - in my rephrasing - are identical. In the first case it refers to the mixture of states - ie. the unknown state of the cat. One typically says in everyday language, in such a context, that the cat is, well, dead or alive. The mathematical definition of entanglement captures this everyday usage. In the second instance there is an attempt to render the classical idea of the cat being dead, (or the cat being alive) but one can not render such a classical idea without re-introducing both possible facts - ie. without re-introducing the very concept of entanglement from which one was trying to disentangle oneself.

--124.168.91.147 (talk) 12:44, 2 September 2009 (UTC)


 * They are not the same. Note that the word "mixture" is linked. --Michael C. Price talk 15:04, 2 September 2009 (UTC)
 * In my rephrasing they are the same. And my rephrasing does not (I argue) alter the meaning/lessness of the original statement. To continue ... —Preceding unsigned comment added by 124.168.125.43 (talk) 23:21, 5 September 2009 (UTC)

One can also rephrase it this way:

"Schrödinger's famous thought experiment poses the question, when does a quantum system stop existing as a mixture of states and become a mixture of states?"

Here, in the second instance, (of "mixture of states") there is no attempt to render the classical idea. The intended classical concept requires a statement (eg. the cat is dead) which can't be expressed without also mentioning the other possibility (the cat is alive), ie. restating the concept of entanglement.

--124.168.91.147 (talk) 20:04, 2 September 2009 (UTC)

The interesting point being made here is that it is not entanglement which is difficult to articulate but in how you would characterise the alternative? How do you represent a classical fact without framing such facts as but an example (ie. but one of two possible facts?)

For example you could ask:

"When does the cat stop existing as dead or alive and become dead?"

The rhetorical answer being:

"When does the cat stop existing as dead or alive and become alive?"

—Preceding unsigned comment added by 202.6.86.1 (talk) 07:07, 3 September 2009 (UTC)

How do we make a valid classical statement such as: the cat is dead, before we know whether that statement is correct, ie. before we know whether the cat is dead? We can't. And more to the point, how do we make such a statement without our statement being just one example of two equally possible statements? We can't.

Now we might like to imagine that once we know whether a cat is alive ( or dead ) that it is then definitely one ( or the other ) yet the very description of this apparent certainty re-introduces the very ambiguity we might have thought we eliminated. This is not a failure of language. If a theory can not be communicated (eg. through language) then what theory are we talking about?

Or not talking about as the case may be.

You can protest in silence if you think it makes any difference.

Every instance of an intended classical description suffer from this. Consider the following:

"(More technically, when does the actual quantum state stop being a linear combination of states, each of which resembles different classical states, and instead begins to have a unique classical description?) If the cat survives, it remembers only being alive."

To which should be added (for a complete description): If the cat does not survive, ...

Everywhere in the article (and this is not limited to the article) there is either a statement of both possible outcomes - which is not a classical description, or there is an ommission. Consider the following:

"Some interpret the experiment to mean that while the box is closed, the system simultaneously exists in a superposition of the states "decayed nucleus/dead cat" and "undecayed nucleus/living cat", and that only when the box is opened and an observation performed does the wave function collapse into one of the two states."

Which should be ammended to say (if we're to be honest, as Einstein would have us believe we weren't):

"... only when the box is opened and an observation performed does the wave function collapse into one or the other of the two states." —Preceding unsigned comment added by 210.84.32.160 (talk) 20:05, 7 September 2009 (UTC)


 * As far as I can see your alternative versions of the sentence; "...collapse into one of the two states." and "...collapse into one or the other of the two states." mean the same thing. -- Chetvorno TALK 06:34, 9 September 2009 (UTC)

Yes - they do mean the same thing. That is the point being made. The meaning is not changed by the omission of: "or the other". The only difference between the following two questions is that the former hides it's silliness, whereas the later makes it's explicit:


 * When does the cat cease being one or the other and become one.
 * When does the cat cease being one or the other and become one or the other.

122.108.178.221 (talk) 04:48, 1 May 2010 (UTC) Actually it is less ambiguous to say before the collapse of the superposition state (observation) that the cat is in a state of being both dead and alive. After the collapse the cat is either dead or alive.

Schrödinger's silly question.

Here is another example of what is being said here. Suppose you see a man (on TV) walking up to a woman in the street and asking her to think of a number between 1 and 100. The woman replys with, say, "43". The man then opens his coat and printed on his TShirt, in big bold letters, is the number "43". A trick. Yes. But what is the trick? Does he have a TShirt that can generate the number? Is the woman just pretending to be a complete stanger? Well, sure.

But what if the woman really was a complete stranger and the number on his TShirt really was always "43". Then how could he possibly do this trick?

He could simply ommit from showing us all the other people he tried this trick on - and who didn't say "43".

--210.84.46.189 (talk) 05:54, 20 September 2009 (UTC)


 * Do you have a criticism of the article? State which text should be changed, and what it should be changed to.  Then we can discuss this concretely.  -- Chetvorno TALK 06:14, 18 October 2009 (UTC)


 * When saying "one" (A) instead of "one or the other" (A XOR B) one is implying (incorrectly) that
 * (A XOR B) == (A AND NOT B)


 * But:
 * (A XOR B) == (A AND NOT B) XOR (B AND NOT A)


 * However saying "one or the other" would ammount to criticism/mockery of Schrodinger's question. But not saying so would ammount to an uncritical acceptance (and an actual error) in relation to his question. Both of which are a problem in terms of Wikipedia constraints. Therefore this discussion sits in the discussion page awaiting a solution (possibly indefinitely).--210.84.46.224 (talk) 23:08, 31 October 2009 (UTC)

Serge Haroche has done actual experiments that mimic the thought experiment, and shown that they are consistent with quantum electrodynamics. See Deleglise S., Dotsenko I., Sayrin C., Bernu J., Brune M., Raimon J.-M. et Haroche S., « Reconstruction of non-classical cavity field states with snapshots of their decoherence », Nature, 455, 2008, 510.

The central question may be phrased:


 * When does the system evolve from a quantum superposition of states to a classical statistical mixture of states?

The answer is that it does so because of coupling to the environment, and the experiment shows that evolution over time. That process is called "decoherence". Another key point of these experiments is that an observation does not have to give a classical result; one can observe a quantum superposition. In terms of the cat, it is perfectly reasonable to observe a state that is a superposition of live and dead, but that state will exist for an extremely short time, because there is always coupling to the environment that will destroy the state.

The article should have a section on how decoherence explains the thought experiment. Stephen leake (talk) 08:37, 12 May 2010 (UTC)