Talk:Many-worlds interpretation/Archive 5

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Archiving

I just ruthlessly archived about 90K of discussion, almost all from 2007, into ./Archive 3. I tried to keep sections together, and put then in chronological order, but there was one place where I found some posts starting with very early (Feb 2007) dates in a much later section, so they must have got jumbled in an earlier re-ordering. I put those in a new section at the beginning, but note that their comments seem to go on into October. Those later comments may possibly belong with a later section altogether.

Does anyone have an appropriate archiving interval for the future? For this article 30 day seems short, but it still might work if there have been no further comments after that interval. Two or three months would likely be fine. Wwheaton (talk) 22:55, 29 December 2008 (UTC)

Hawking does believe the other worlds are real

I have a book with essays and lectures given by Hawking. In one lecture, Hawking claims in another universe Germany won WWII. Every Everett world does not necessarily generate every historical outcome that humans can think up. All the quantum worlds ought to look remarkably the same, as most quantum divergences do not impact the macro world. Schrodinger's Cat is an exception to the rule.

When Hawking was asked if humans have free choice, he answered, "Ultimately we don't have free choice since every quantum possiblity is realized. But we don't know which universe we are in, so for all practical purposes we do have free choice."

It reasonable and logical to believe that the universe contains more rather than less.

No one should comment on Hugh Everett's Many-Worlds until they have read Max Tegmarks's articles in Scientific American, and his other articles on the subject. 29 December 2008 (User:66.229.53.158)

Hi 66.229.53.158, can you please use four tildes, "~", to sign & date your posts. I have added the date you started this section above. Also, it is usual & helpful to put the later sections at the end, so this needs to be moved to the bottom of the file. (Clicking on the "New section" tab does this automatically.) Thanks. Wwheaton (talk) 05:35, 1 January 2009 (UTC)

A funny thing happened on the way to the . . .

Hugh Everett's Many-Worlds does not claim "every possible outcome" exists in some universe. That would be Max Tegmark's AUH, "All Universe Hypothesis." Every quantum possiblity is far less than every possible outcome. Please read Max Tegmark's articles in Scientific American. When I edited this article to say that "Many-worlds claims to resolve SOME of the 'paradoxes'" others here went ballastic and reverted my edit. A "paradox" is nothing more than an apparant contradiction. Therefore, there is no need to have quotes around the word "paradox." Otherwise, there always ought to be quotes around the word.

My comment refers to this line in the article:

"Many-worlds claims to resolve all the 'paradoxes' of quantum theory since every possible outcome to every event defines or exists in its own 'history' or 'world.'

I'd like to see more of Michael Clive Price's Hugh Everett FAQ in this article. This article keeps going through many incarnations. This is not the best one. —Preceding unsigned comment added by 66.229.53.158 (talk) 18:06, 29 December 2008 (UTC)

my problum with the above statment is that "Every quantum possiblity" would equal more, not less than all possible outcomes, because all possible outcomes could have an infinite number of quantum varriations.98.217.227.114 (talk) 17:54, 1 June 2009 (UTC)

The many-worlds interpretation has nothing to do with the anthropic principle

Under advantages of the MWI on wikipedia this is listed:
"* MWI (or other, broader multiverse considerations) provides a context for the anthropic principle which may provide an explanation for the fine-tuned universe."

However the MWI has nothing to do with physical constants changing and no indication shows that physical constants would change in a MWI style multi-verse, this is often confused with the chaotic inflation theory multi-verse, where physical constants would change

Why does wikipedia make such a blatantly inaccurate statement about the MWI? --129.2.175.79 (talk) 20:48, 8 April 2009 (UTC)

Many sources disagree with you.--Michael C. Price ^talk 07:27, 9 April 2009 (UTC)

Which source is that that disagrees with me? The sources I see disagreeing are the same ones that confuse the MWI with the chaotic inflation theory, usually sources not coming from actual physicists. There's no indication that physical constants could/would change in the many-worlds style multi-verse. Paul Davies and other physicists are referring to the chaotic inflation theory style multi-verse which has absolutely nothing to do with the MWI. Can you provide any source from a physicist or peer reviewed journal which shows that in the many-worlds style multi-verse physical constants will change?

Why does wikipedia make such a blatantly inaccurate statement without any sources? Wikipedia's own article on the multiverse is much more accurate and explains exactly what I'm saying. Why would wikipedia insist upon inserting such a blatantly inaccurate misleading statement about the many-worlds interpretation deceiving people into thinking in the many-worlds physical constants change? How or why is this statement an accurate "advantage" of the many-worlds interpretation? --141.156.133.161 (talk) 12:57, 9 April 2009 (UTC)

1. Davies is not confusing chaotic inflation theory with MWI.
2. It is not known which "constants" are constants by fiat (non-MWI) and which are the result of spontaneous symmetry breaking (MWI). Hence the demarcation between the MWI / non-MWI multiverse with respect the nature of the physical constants is unknown.

1. The anthropic principle is not just about physical constants. The initial conditions are also within its scope. cf Rare Earth hypothesis.

--Michael C. Price ^talk 13:49, 9 April 2009 (UTC)

It's just like I said absolutely no reliable source claims that physical constants can change in the many-worlds style multi-verse. It's no wonder wikipedia is known for inaccuracy and foolishness. If it has nothing to do with physical constants why does it say it's an advantage for an explanation of a "fine-tuned universe"?. A fine-tuned universe specifically refers to physical constants, and it falsely lists the MWI as an explanation of this Paul Davies does not use the many-worlds interpretation to explain the fine-tuned universe or physical constants. So in conclusion the statement still remains blatantly inaccurate and misleading since fine-tuning and physical constants have nothing to do with the MWI.--141.156.133.161 (talk) 13:58, 9 April 2009 (UTC)

What part of 2 & 3 do you not follow? --Michael C. Price ^talk 15:11, 9 April 2009 (UTC)

The part of 2 & 3 I don't follow is that in the wikipedia article it specifically states that the MWI explains the fine-tuned universe which refers to physical constants changing. Which is ofcourse a blatantly inaccurate foolish statement. A fine-tuned universe refers strictly to physical constants. The MWI does not explain the physical constats of the fine-tuned universe as listed. The statement made says that the MWI "may provide an explanation for the fine-tuned universe" which is obviously false and inaccurate. Do you know what a fine-tuned universe means or refers to? All the MWI can at best show is that all things that can possibly occur, occur. So why is the statement under advantages not changed to not be misleading and foolish? It's no wonder wikipedia's accuracy is known as laughable with the most unnaturally foolish wiki editors, even after proven wrong, knowing that the MWI does not explain a fine-tuned universe as the article falsely claims, they still insist it should remain listed. So unnaturally foolish

The statement "may provide an explanation for the fine-tuned universe" which is blatantly inaccurate should be removed it and should say that the MWI may only solve anthropic problems not involving physical constants in order to be accurate and not misleading

"The fine-tuned Universe is the idea that the conditions that allow life in the Universe can only occur when certain universal physical constants lie within a very narrow range, so that if any of several fundamental constants were only slightly different the universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is presently understood."--141.156.133.161 (talk) 02:42, 10 April 2009 (UTC)

You're repeating yourself, yet nowhere have you addressed point 2 about Spontaneous symmetry breaking. --Michael C. Price ^talk 06:03, 10 April 2009 (UTC)

No physicist or peer-reviewed source claims that physical constants could/would change in the MWI style multi-verse, your point about spontaneous symmetry breaking refers only to the chaotic inflation theory not the many-worlds and does not belong in an Encylopedia, some how by some unknown means you still believe physical constants could/would change based off faith or "belief without proof". How does such a claim belong on Wikipedia? All your statement does in encourage confusion between the the MWI and other style multiverses. The fine-tuning problem is not solved by the many-worlds either way you look at it.

No where have you ever answered the question and your response can be reduced to "It's unknown if other multiverse theories where physical constants change are true" so I put it there" so foolish--71.191.50.222 (talk) 14:59, 11 April 2009 (UTC)

(deindent) Inflation, being a quantum process, is subject to MWI splitting. Ergo any spontaneous symmetry breaking and resetting of constants is subject to MWI. --Michael C. Price ^talk 23:55, 11 April 2009 (UTC)

You would only have to pre-assume that other style multi-verses are true in order to believe that physical constants can change in a MWI style multiverse, if the MWI alone is true and the other multiverses are false, then no physical constant changes, no peer-reviewed source ever indicates that physical constants change in the MWI, and Paul Davies does not claim constants change in a MWI style multi-verse to date, where did you get this idea?--68.163.64.202 (talk) 01:32, 22 September 2009 (UTC)

From his book, Other Worlds, chapters 8 The Anthropic Principle & 9 Is the Universe an accident? --Michael C. Price ^talk 10:24, 22 September 2009 (UTC)

BTW Paul Davies was not referring to inflation on his Other Worlds book. No Mention of it at all. Not surprising since it was published in 1980. And he makes the same point I've made above -- that the constants may vary. --Michael C. Price ^talk 00:12, 12 April 2009 (UTC)

The style of the anthropic principle Paul Davies is referring to has nothing to do with physical constants changing at all--68.163.64.202 (talk) 01:32, 22 September 2009 (UTC)

See Other Worlds, chapters 8 & 9 The Anthropic Principle & Is the Universe an accident? --Michael C. Price ^talk 10:24, 22 September 2009 (UTC)

If Paul Davies really did claim that constants can change in a MWI style multi-verse then he is obviously mistaken, do you have a quote from the book? When the electrons split in the double slit experiment nothing indicates that the constants would change and all experiments have them having the same physical constants. Spontaneous symmetry breaking would not occur. To date wikipedia is the only source which claims that constants can change in a MWI style multi-verse. --71.191.139.37 (talk) 11:18, 26 September 2009 (UTC)

The idea is that the dynamical symmetry breaking was a quantum process that happened at a certain point in time, and MWI implies that the result was a realization of all possible symmetries. The symmetries don't re-break now when worlds split, but there are worlds "out there" where the symmetry breaking went a different way. -- BenRG (talk) 13:11, 26 September 2009 (UTC)

Advantages and Objections sections

There is in my opinion a serious problem with the Advantages and Objections sections. This is supposed to be an encyclopedia article, not a bulletin board. These sections read like someone just cut and pasted some debate from the talk page onto the actual article page. Completely inappropriate.--76.167.77.165 (talk) 03:26, 6 May 2009 (UTC)

Only one of the points has been copied from an on-line FAQ, and it is referenced. The rest have been composed here on wikipedia.--Michael C. Price ^talk 07:36, 6 May 2009 (UTC)

I didn't say that it *was* copied from a bulletin board, merely that it read as though it had been. The style is completely inappropriate.--76.167.77.165 (talk) 21:17, 6 May 2009 (UTC)

I agree, i fell that a style overhal is needed i was confused by this section at first, i though that the computer had jumped to the talk page for a minute98.217.227.114 (talk) 17:56, 1 June 2009 (UTC)

I also object to the structure of the Advantages and Objection (what is now the "Common Misconceptions") sections. They are presented in a very un-encyclopedic style with the bulleted lists and the Objection/Answer format. Moreover (and this is even more relevant given the renaming of the section to "Common Misconceptions"), the current format gives the impression that there is nothing wrong with the MWI. Even worse, it gives the impression that those who think that there's something wrong with MW don't have criticisms, but merely suffer from misconceptions of the view.
This, as far as I am aware, simply isn't true. There are a number of physicists and philosophers of science that do not accept this view because they believe that it suffers from major flaws. Ignoring these positions (as is done in the propagandically named and non-sequitor filled "Acceptance among Philosophers" section) or sweeping them under the header of "Misconceptions" is responsible for this article's apparent bias and dogmatic tone. Is there a reason that this article lacks an Objection or Criticism section that isn't filled with Everettian responses ensuring that the view's defenders always get the last word? ZRPerry (talk) 20:20, 18 November 2009 (UTC)

What used to be called the "disadvantages" section has been renamed so many times by various people for various reasons that I don't really care anymore. If you want to have another go I don't care (you won't be the last either, I'm sure).

However I would object to watering down the content on some mistaken idea of what NPOV means. For instance, it is a common misconception that MWI violates conservation of energy or Ockham's razor, and has been amply rebutted many times. So why shouldn't we say that? And it is all pretty well sourced.

As for getting the last word, well come up with a coherent rebuttal of a rebuttal and add it. But you can't stop that being rebutted either. I see nothing unencyclopedic about nested bullet points; on the contrary they add clarity to a confused subject - it up to the reader to judge their validity. (It was a similar case in the Bohm article where in a similar section (now sadly lost) the Bohmite POV got the last word; some readers commented that it was the best part of the article.... I've been holding my tongue about the sad decay of the clarity of the Bohm article on the talk page, but I won't be so quiet here.)

I didn't see "acceptance amongst..." as a loaded term, but if you want to change the title, go ahead. BTW I think the philosophers and physicists sections should be merged together. --Michael C. Price ^talk 21:28, 18 November 2009 (UTC)

That's actually very illuminating, Michael. I was under the impression (from things I had seen on the talk page while the Bohm article still had that Q/A section) that this format was undesirable in a Wikipedia article. If you think that this sort of format is appropriate, then I stand corrected. I do think, though, that this sort of format is more susceptible to editor bias than a typical "Criticisms" section.

I have no problem with keeping the parts of the article that clear up common misconceptions. My objection is that there are legitimate objections which seem to have been assimilated into the misconception section, and there is no bona fide Criticism section to put them. As the article stands, the only place to put a dissenting view is in a section whose title flatly asserts that the views contained within it are baseless. That sounds like POV.

Once again, I'm happy with clearing up common misconceptions. However, there are worries that opponents of the MWI have which aren't just common misconceptions. Making sense of probability in the Everett picture is an obvious example, but it's not the only one. I'm not knowledgeable enough to crank out such a section in its entirety, but I'll look around, when I have time, to see if I can find one or two good surveys of the problems with MW that aren't obviously based on ignorance.

....Okay, so I just noticed you merged the "Acceptance among.." sections and renamed them "Reception". I support this move wholeheartedly. I also think that this might be a good place to include some of the objections which don't obviously belong in the "Misconceptions" section. Hats off to you, good sir. You have addressed (most of) my concern before I had even managed to voice it. Good show! ZRPerry (talk) 17:54, 19 November 2009 (UTC)

undue weight placed on testability

I think there is a problem with the article, which is that it seems to place undue weight on claims that interpretations of quantum mechanics such as MWI are testable. The view of the overwhelming majority of physicists is that interpretations of QM are *not* testable.--76.167.77.165 (talk) 03:36, 6 May 2009 (UTC)

Nevertheless the claim of testability has been made by reliable sources.--Michael C. Price ^talk 07:38, 6 May 2009 (UTC)

I didn't say that it hadn't been made by reliable sources, I said that it gave undue weight to an obscure point of view: These are two separate WP policies: Wikipedia:UNDUE and Wikipedia:Verifiability --76.167.77.165 (talk) 21:22, 6 May 2009 (UTC)

It is not obscure within the MWI field. --Michael C. Price ^talk 21:27, 6 May 2009 (UTC)

Huh? The MWI is testable as all it assumes is unitary time evolution, while CI says that time evolution is, in general, not unitary, because it allows for violations of unitary time evolution during observations. So, if you lock an observer up in a perfectly isolated box and that observer performs measurements, then, according to CI, the isolated box will not undergo unitary time evolution.

This then implies that any isolated system containing a large number of particles will not evolve according to the Schrödinger equation, because you can always expand the state vector of such a many particle system in a basis that can be interpreted as containing some observer who is measuring something.

Any non unitary time evolution will show up as decohorence in the absense of any coupling to the environment, therefore the MWI is falsifiable. Count Iblis (talk) 16:01, 6 May 2009 (UTC)

You're right, MWI is testable in that it is unitary and the CI is non-unitary. But some Copehangenists claim that CI would predict the same results Deutsch claims for the split-mind experiment. Not because of any deficiency in MWI but rather because CI is a slippery woolly beast that can predict whatever you want it to predict. So I think it fair to say that the claim of testability is contested.--Michael C. Price ^talk 20:15, 6 May 2009 (UTC)

Count Iblis, WP's Wikipedia:UNDUE policy doesn't have anything to do with whether you can make your own plausible argument about this.--76.167.77.165 (talk) 21:36, 6 May 2009 (UTC)

Dear 76.167.77.165, an argument based on reason is appropriate for a science article. A logical argument will be repeated in the literature, as is the one Count Iblis makes.--Michael C. Price ^talk 04:51, 7 May 2009 (UTC)

The measurement problem

Why do the particles act the way they do when the are observed? They must think they can do whatever the hell they want. Well not when im watchin. Its obvious that these guys will just mess around unless you force them to behave accordingly. I did a double split experiment today, i used an A4 sheet of paper, taped to the window with two slits cut in it. When observed they acted like expected, but sure enough when i looked away they started acting erratical again. Basically i would like to hear some methods on how to control the particles, i propose building a quantum scarecrow that would trick them into behaving how i want. Would this work? If not why not? Any other ideas? —Preceding unsigned comment added by 193.120.116.147 (talk) 12:42, 23 May 2009 (UTC)

See the link in the section title. --Michael C. Price ^talk 08:12, 2 June 2009 (UTC

Falsifying MWI

Neither Afshar not Cramer have succeeded in publishing this claim, which is pretty non-sensical, although for different reasons. In Afshar's case he claimed that the MWI violated conservation of momentum, and Cramer's claim of busting MWI relied on the arbitrary claim that the photon couldn't intefere with itself because it was already in different universes. Anyway, big claims like this require a least some degree of peer-review which both are entirely lacking.--Michael C. Price ^talk 20:50, 13 August 2009 (UTC)

And is every other claim in the article peer reviewed? 1Z (talk) 21:01, 13 August 2009 (UTC)

The scientific claims, yes. Do you have any in mind? --Michael C. Price ^talk 21:06, 13 August 2009 (UTC)

That;s what? Scientific as opposed to interpretive?

I noticed you added a snip to the Ashfar article that Cramer's claim was not peer reviewed. However, most of the objections to Afshar in that article aren't peer-reviewed either. You are not going to buy yourself anything this way.1Z (talk) 21:09, 13 August 2009 (UTC)

If the objections are not peer reviewed I have no problem with that being stated as well. --Michael C. Price ^talk 21:13, 13 August 2009 (UTC)

Maybe you could do so. Or maybe you could consult on WP:Reliable sources/Noticeboard‎ 1Z (talk) 21:15, 13 August 2009 (UTC)

I'll leave that to others, since it doesn't directly affect the Cramer claim. As I said, Cramer's claim is a big one; that it's not peer reviewed is significant.--Michael C. Price ^talk 21:29, 13 August 2009 (UTC)

THere are a lot of big claims in the article. If I were you I would make sure the ones you agree with are peer-reviewed too. Or just go for the normal standards of notability. 1Z (talk) 21:37, 13 August 2009 (UTC)

Lemesee--about 7 references to your own FAQ....1Z (talk) 21:39, 13 August 2009 (UTC)

All added by other people.--Michael C. Price ^talk 21:43, 13 August 2009 (UTC)

That's crashingly irrelevant. If you really think that everything in the article should be peer reviewed, you should be removing them and the claims they support as well. It is blatantly obvious that you are only removing material that opposes you POV. 1Z (talk)

About as irrelevant as your original attempt-at-a-snide-comment, yes.

If you're unhappy with any claims made, tag them. I am always happy to improve the sourcing of the scientific (which includes interpretational) claims. --Michael C. Price ^talk 22:03, 13 August 2009 (UTC)

I don't see any need to tag evey claim so long as they are supported by WP:RS and WP:V. It makes the article difficult to read. I am quesitoning your invention of a policy that is specific to peer-review, and your selctive application of it. 1Z (talk) 22:52, 13 August 2009 (UTC)

Controversial scientific claims normally require peer-reviewed sourcing. Claiming to have falsified an interpretation of QM is pretty controversial. Removing such a claim, or explicitly stating that it isn't peer-reviewed, is consistent with WP:RS and is usual practice. --Michael C. Price ^talk 07:39, 14 August 2009 (UTC)

The falsehood and the truth of MWI are controversial. There is a huge difference between writing that so-and-so has been falsified, and writing that so-and-so has claimed it has been falsified. 1Z (talk) 08:34, 14 August 2009 (UTC)

(deindent) The status of every interpretation is controversial (that's why they are only interpretations), but claiming to have falsified an interpretation is a higher order claim, and extraordinary claims require extraordinary proof. Writing that so-and-so claims something is a partial solution, but so is stating whether so-and-so's claim has been peer-reviewed. --Michael C. Price ^talk 08:47, 14 August 2009 (UTC)

You didn't qualify the claim in the many worlds article, you deleted it. 1Z (talk) 08:48, 14 August 2009 (UTC)

Yes, because the views of Cramer and Afshar are so fringe as to be irrelevant to MWI. Relevant to Afshar experiment, but not to the wider world. Also note the line "Exceptional claims in Wikipedia require high-quality sources.[6] If such sources are not available, the material should not be included." This material fails the high-quality source test.--Michael C. Price ^talk 09:03, 14 August 2009 (UTC)

The whole subject is fringe. The claim being made is that someone said something. 1Z (talk) 09:37, 14 August 2009 (UTC)

MWI is not fringe.--Michael C. Price ^talk 09:44, 14 August 2009 (UTC)

Peer-review is necessary to establish something as scientific fact. It is not necessary to establish that so-and-so said such-and-such.1Z (talk) 08:57, 14 August 2009 (UTC)

True, but the claims themselves still fail WP:REDFLAG. I can find claims that the MWI implies telepathy or that we pass between worlds when we dream, but we don't include them in the article. --Michael C. Price ^talk 09:03, 14 August 2009 (UTC)

I doubt that such claims were made buy scientists. What do you mean the claims fail? 1Z (talk) 09:37, 14 August 2009 (UTC)

They were made by scientists. --Michael C. Price ^talk 10:01, 14 August 2009 (UTC)

I notice your latest edit summary is a bit of WP:OR about the status of interpretations. There are in fact grey areas. I have seen varying claims about the falsifiability of MWI, Bohm, COpenhagen ,e tc. You don't get to edit onthe basis of your own WP:POV of what is or is not an interpretation. 1Z (talk) 09:41, 14 August 2009 (UTC)

It is actually fairly mainstream that interpretations can't be falsified by experiments that preserve the canonical equations. This is not OR. This is especially relevant to the MWI which rejects all processes except the canonical equations. This is also not OR. --Michael C. Price ^talk 10:01, 14 August 2009 (UTC)

BTW, you have made 3 reverts in 24 hours.1Z (talk) 09:46, 14 August 2009 (UTC)

IP edits don't count, especially when they are of low-quality. For instance an IP edit just claimed that poll results require peer-review publication. They don't because a poll result is not a scientific claim.--Michael C. Price ^talk 10:19, 14 August 2009 (UTC)

It would be helpful to start a discussion based on first principles instead of just quoting from articles (that may be flawed). To see that Afshar and Cramer are talking nonsense, you really need to do that. See also: Wikipedia:Editing scientific articles (which isn't complete yet, so comments are welcome). Count Iblis (talk) 15:15, 14 August 2009 (UTC)

Yes, I was thinking that myself, with your essay in mind. I'm sure there are lessons here that can find their way into the essay.

Coincidentally, I have just unearthed a reference that lays the Afshar experiment to rest, which also renders Cramer's opinion rather moot as well.--Michael C. Price ^talk 17:31, 14 August 2009 (UTC)

Deleting sections

I'm thinking of deleting some sections from the article that I feel are generally not very accessible. They are:

6 Brief overview

7 Relative state

9 Axiomatics

10 Example

11 Partial trace and relative state

To someone who doesn't understand QM they are gibberish. And to those that do, I'm sure a far simpler explanation must be possible.

Some of the material (e.g. Bloch sphere) has it own article.

Anyone have any objections? --Michael C. Price ^talk 00:24, 23 November 2009 (UTC)

IMO "6 Brief overview" and "7 Relative state" are Ok.--Dc987 (talk) 08:04, 24 November 2009 (UTC)

Okay, I'll leave them in. --Michael C. Price ^talk 08:58, 24 November 2009 (UTC)

A science fiction reference in the introduction?

A map from Robert Sobel's novel For Want of a Nail. It's nice, but it belongs to "Many worlds in literature and science fiction". --Dc987 (talk) 08:07, 24 November 2009 (UTC)

I did think about that. But the point is that it is fact as well - if we take MWI seriously then these alternate histories actually exist. Also I felt it was more accessible to the general reader than the text.--Michael C. Price ^talk 08:10, 24 November 2009 (UTC)

After encountering the science fiction reference the reader would simply think that the rest of the article is also a science fiction. --Dc987 (talk) 08:30, 24 November 2009 (UTC)

I felt that the demands of instant accessibility outweighed that danger, but it is a judgement call, I'll grant. --Michael C. Price ^talk 09:06, 24 November 2009 (UTC)

I think it would be beneficial if this article was: less accessible for crackpots; taken seriously by physicists/students. Referencing science fiction and instant accessibility doesn't help here. --Dc987 (talk) 10:59, 24 November 2009 (UTC)

I would like it more accessible generally (yes, even for crackpots). But who are the general readers? They are (I guess) mostly non-physicists. Statements about collapsing wavefunctions and decoherence will mean nothing to them (and probably not much to most freshers either).

Ideally I would like a graphic such as the ones in some popularisations that show cartoon strips diverging, but I can't find any in the public domain.

--Michael C. Price ^talk 11:36, 24 November 2009 (UTC)

What do you want to be shown on the film frame? It's fairly easy to make a graphic like this in the Google SketchUp (3d modeling tool). --Dc987 (talk) 20:11, 24 November 2009 (UTC)

Cartoon strip: [1] And my favourite, although I doubt Nature would release copyright, [2] I'll try the artist. --Michael C. Price ^talk 21:44, 24 November 2009 (UTC)

I can make one like this [3]. In fact I can do much better, with more realistic 3d. But I don't like the idea of people to be shown on the frames. It's weird. What is acceptable in popularizations is not suitable for an encyclopedic article. I'm not going to make a graphic with people and I would object to placing it in the article.

If you would agree to tone down it a bit and show a pencil falling in two directions, or a cat, or electrons taking both paths, or something like that - I can make an illustration. --Dc987 (talk) 22:19, 24 November 2009 (UTC)

We shall have to disagree about popularisations. However cats would be a good topic, and since we both seem to like that idea, let's go with cats. --Michael C. Price ^talk 22:26, 24 November 2009 (UTC)

Ok. I'll use this [4] as a starting point. --Dc987 (talk) 22:52, 24 November 2009 (UTC)

Combined with splitting cartoon strip, that would be good. --Michael C. Price ^talk 23:09, 24 November 2009 (UTC)

Here it is:

--Dc987 (talk) 05:24, 25 November 2009 (UTC)

Cool. Is it possible to flesh out the cat a bit more? Looks a bit ghostly. --Michael C. Price ^talk 10:20, 25 November 2009 (UTC)

Er.. Flesh out? Make it black? Pink? --Dc987 (talk) 10:53, 25 November 2009 (UTC)

I just mean more realistic or photographic-like (this might not be easy?). Like this? Don't get me wrong, it's good as it is, but if we can make it better before release... --Michael C. Price ^talk 11:07, 25 November 2009 (UTC)

Personally, I'd go with the cat as it is. A photorealistic cat would clutter the image. Gabbe (talk) 16:10, 25 November 2009 (UTC)

My only concern is that the cat is a grey, ghostly silhouette, whereas the other objects are shown in more detail and are coloured. I sure some people will read some significance to that. One thing I've learnt is that if there is some way to misunderstand MWI, no matter how stupid it might seem to us, then it will be misunderstood. --Michael C. Price ^talk 17:27, 25 November 2009 (UTC)

Ok. I'll try fixing it. BTW, the full resolution image, does it look ghostly? --Dc987 (talk) 21:43, 25 November 2009 (UTC)

Shadowy might be a better word. --Michael C. Price ^talk 22:23, 25 November 2009 (UTC)

It's difficult to vectorize the image, too many details and the resulting vectorization is simply too large. That could have improved the detail level of the preview.

How about the white cat? Any better? --Dc987 (talk) 23:37, 25 November 2009 (UTC)

Not really, it's the relative lack of detail (e.g. eyes, whiskers, colour variation) that looks odd. --Michael C. Price ^talk 00:09, 26 November 2009 (UTC)

Eyes and whiskers... Mmmm... Wouldn't that be a move towards CCC? --Dc987 (talk) 01:24, 28 November 2009 (UTC)

No, it was the radioactive decay that started the split, not the cat.--Michael C. Price ^talk 05:07, 28 November 2009 (UTC)

---

"These alternate histories actually exist" <- extraordinary claims require extraordinary evidence. --Dc987 (talk) 08:32, 24 November 2009 (UTC)

Everett's PhD thesis is that evidence. --Michael C. Price ^talk 09:06, 24 November 2009 (UTC)

Ok. The text is better now. --Dc987 (talk) 10:59, 24 November 2009 (UTC)

Approximation

It could be worth mentioning that MWI (and QM in general) is an approximation in a sense that the time parameter is: 1) not compatible with GR; 2) shared between the branches. --Dc987 (talk) 10:10, 25 November 2009 (UTC)

1) is a tricky point (since quantum gravity is incomplete). 2) is certainly true until you start trying to incorporate GR as quantum gravity. Then it suffers from 1). Any sources in mind? --Michael C. Price ^talk 10:25, 25 November 2009 (UTC)

Many worlds is not every possible alternative history

"all possible alternative histories actually exist.[1]"

This is not actually quite correct. "Many" worlds is not the same as "all possible" worlds. (And I note that the reference says that "all possible outcomes of an experiment'' exist, not all possible histories.)

The map is only tangentially relevant to the MWI; I'm going to move it down to the science fiction references section. Any reason to not put the DSC987 image actually in the article? Geoffrey.landis (talk) 15:04, 27 November 2009 (UTC)

Well, if you'd been reading the talk page, it's not quite finished.

The "an experiment" is an unnecessary qualifer, since MWI is not anthromorphic. Anyway, the main text includes the de Witt line about every transition in every star etc splits the universe. So it's obviously not just experiments that split us. --Michael C. Price ^talk 16:19, 27 November 2009 (UTC)

That is not obvious at all. "every transition in every star splits the universe" may be de Witt's line, but it most certainly is not Everett's interpretation of Everett's concept. And the words "an experiment" is quoting from the deWitt reference; so you should talk to him about it, not me. (However, it's true that the word "observation" does tend to be misleading when you're translating quantum mechanics into English.) Geoffrey.landis (talk) 21:35, 27 November 2009 (UTC)

Unfortunately it is impossible to speak to either Everett or de Witt any more, so we have to go with what they said and what others said and say about them. According to various reports (which I'm happy to source) Everett subscribed to de Witt's presentation of Everett's theory. So if de Witt was an extreme "splitter" - and we seem to agree he was - then so was Everett. If you have a source that says that Everett and de Witt disagreed about this, then I'd like to see it.--Michael C. Price ^talk 22:00, 27 November 2009 (UTC)

My inclination would be to suggest that if you want to know what Everett thought, you should read what Everett actually wrote. Geoffrey.landis (talk) 18:29, 28 November 2009 (UTC)

Have read everything he wrote and ever published on many-worlds. Same as de Witt, just different terminology. --Michael C. Price ^talk 19:55, 28 November 2009 (UTC)

Excellent. Then, since Everett never said nor implied that "every transition in every star splits the universe", let's not attribute that to him. Geoffrey.landis (talk) 00:46, 30 November 2009 (UTC)

He never made that exact quote, but that's not the same as not implying it. And anyway, it is attributed to the theory, not the man. --Michael C. Price ^talk 00:56, 30 November 2009 (UTC)

The article is about Many Worlds Theory, not about Everett. If De Witt said it, it goes in the article.- Wolfkeeper 01:24, 30 November 2009 (UTC)

If, in fact, De Witt says something that's significantly inconsistent with what Everett says, no, I don't see why it should be put in the article with a statement "this is what the MWI says". Geoffrey.landis (talk) 00:01, 1 December 2009 (UTC)

You may not, but extending or reinterpreting or reformulating parts of a theory after it has been invented is a pretty normal part of science. For example Planck's constant was originally derived on the assumption that the speed of light was not constant. Newtonian mechanics will have certainly grown after his death, and Maxwell's equations are now expressed very differently.

Also, the wikipedia works by adding significant facts that are associated with the topic of an article, and de Witt is certainly notable.- Wolfkeeper 00:46, 1 December 2009 (UTC)

Wolfkeeper's point is well taken, but in fact although DeWitt and Everett expressed themselves differently at times, I'm not aware of any inconsistent positions they held. --Michael C. Price ^talk 00:58, 1 December 2009 (UTC)

I am finally happy

I am finally happy with the way this article is written. I am glad Lethe (or whatever his name was) is no logner involved with it. Rod Sterling got there first. Many Twilight Zone episodes postulate the existance of paralllel universes. One can't help but wonder if The Twilight Zone planted a seed in the mind of Hugh Everett. —Preceding unsigned comment added by 174.48.138.88 (talk) 01:38, 15 December 2009 (UTC)

I'm glad you like the changes. I'm still concerned about some of the content of "brief overview" and "relative state", but at least they are short. As for Rod Sterling I can definitely say that he was no influence on Hugh Everett, since the TZ came out after Everett's work was published. --Michael C. Price ^talk 20:52, 15 December 2009 (UTC)

The words below sound like something I wrote here eons ago. I must be (User:66.229.53.158) I hope by encountering my former self here, I don't create some sort of paradox that unravels the universe.

There are two theoretical ways to travel back in time. If anything were to travel back into time taking its own original time-line, it would come into existence where it once existed. For example, if you were to travel one second back in time, and materialized, you would materialize where once existed provided you are not moving (whatever that means). The atoms of the body that traveled back in time will occupy the exact same place as the atoms of your body that existed one second ago. This would not be a good thing, since two protons cannot occupy the exact same space. However, there is another way to travel back in time without encountering your own history. That could happen if time was a spatial dimension. With apologies to Hartle and Hawking: for example, if every longetude line on a globe was a time-line, and the South Pole represented the beginning of time, you could reach the North Pole then continue on in a straight line to the S. Pole. You would travel back in "time" without actually retracing your steps.

Some physicists claim that entropy creates the arrow of time. When entropy increases that is an indication the universe is expanding or vice versa. When the universe contracts entropy decreases. It is interesting to imagine what would be the case if you stretched a globe into a torus by stretching it out so that the north and south pole touched at a point, and the equater was antipodal. What makes this case so interesting? That would be like joining the big bang singularity with the big crunch singularity. Of course, there is not going to be a big crunch. But if there were . . .

Hawking does believe the other worlds are real I have a book with essays and lectures given by Hawking. In one lecture, Hawking claims in another universe Germany won WWII. Every Everett world does not necessarily generate every historical outcome that humans can think up. All the quantum worlds ought to look remarkably the same, as most quantum divergences do not impact the macro world. Schrodinger's Cat is an exception to the rule.

When Hawking was asked if humans have free choice, he answered, "Ultimately we don't have free choice since every quantum possiblity is realized. But we don't know which universe we are in, so for all practical purposes we do have free choice."

It reasonable and logical to believe that the universe contains more rather than less.

No one should comment on Hugh Everett's Many-Worlds until they have read Max Tegmarks's articles in Scientific American, and his other articles on the subject. 29 December 2008 (User:66.229.53.158) —Preceding unsigned comment added by 174.48.138.88 (talk) 01:24, 15 December 2009 (UTC)

All the quantum worlds ought to look remarkably the same, as most quantum divergences do not impact the macro world. Schrodinger's Cat is an exception to the rule. That depends in what you mean by "microscopic". The butterfly effect will normally magnify small diveregences without limit. --Michael C. Price ^talk 14:35, 16 December 2009 (UTC)

The butterfly effect can occur in classical mechanics but doesn't occur in quantum mechanics - - a small change in an initial statevector produces a relatively small change in the final statevector;this is a one liner from the Heisenberg equation.Rekcana (talk) 23:00, 4 February 2010 (UTC)

You are confusing the linearity of the wavefunction with the non-linearity of the many-particle states. The butterfly effect occurs in QM, just like CM; it has to since QM can model CM. --Michael C. Price ^talk 02:00, 7 February 2010 (UTC)

Rekcana's link

But I'm not here to wow the crowd. I would like to make several points. The qu idelines for wikipedia articles are incredibly vague - no original research, no unverifiable material, no non neutral content.

Jumping Jehozaphat!! There is original research in Wiki all over the place. For example, do you believe Lev Vaidman or Bennett believe their external links to MWI aren't research.University employees don't waste time on publications they can't justify as research. No unverifiable material - - that's also a fine one. The whole last thirty years of physics is largely unverifiable but, I assume, wikipedia has articles on string theory. Finally, just because a contributor does or doesn't cite a pound of verbiage elsewhere in agreement with her/his wikipedia entry is not the final determinant of verifiability. I'd rather think that verifiability preferably rests on whether one states assumptions and arrives at conclusions either by proffered logic and math or at worst citation of some other source that does. Introducing a derivation or two is good, not bad. I don't think I even have to comment about how hopeless it is to avoid nonneutrality. Affiliated academics pretty nuch always block unaffiliates from peer review journals.Everybody wants to contribute their two cents and how can this not be true for Wikipedia. How can any biliographic(i.e., ext link) or footnote reference to an authored work NOT contribute to someone's curriculum vita ? I think it is just not possible.

Now I have had a very short comment within the MWI article's main body for about a year pointing to my website hosted by Bravehost.com which I believed improved some of the extant explanations. Since the contributed sentence or two was rather peremptory in claiming to be an improvement I understood when it was edited out. But I firmly believe it is pretty much on topic, verifiable in the way I've discussed above, and doesn't explicitly blow the author's own horn anymore than many another external link - - so that is where I put it back at the end of January 2010. Since then the author of the FAQ external link has seen fit to edit my external link out at every opportunity.

So he and I are now at a Mexican standoff, editing each other out and ourselves in as fast as possible. Because I don't think either of us benefits from a prolonged contest of wills of this nature, today I offer the olive branch by leaving his piece in and just reentering mine. Can't we both agree that two contributors to the external links section commit an ethical breach involving conflict of interest by continuing in such fashion to edit out each other? I notice also that some of the participants in this discussion page are willing and able and perhaps eager to debate for ages some issue or another. Not me. I'm 61 years old. Especially on something as relatively minor as an external link why not let anybody have their say? At the end of the day, why not give the reader an opportunity to do their own filtering? I, for example, think a good portion of the Wiki article is dubious - - but I'm not looking to deny anyone their say. The only other comment I have to make at this time is - - c'mon - - I got a 99 percentile in every verbal aptitude test I ever took and I just don't think blanket characterization of my link as insufficiently literate flies. I am willing, for my part, to retract characterization of my antagonist's FAQ external link as "juvenile", a "book report", etc.(I still am not that familiar with the voluminous descriptions of how edits of one type or another work so for that reason I will perhaps repetitiously mention I have username rekcana(David Anacker) and this is 2:43PM USA Pacific Time, 2/4/2010.)Rekcana (talk) 23:00, 4 February 2010 (UTC)

1. Your link is poorly written. Even the first sentence of the abstract is ungrammatical.
2. Says nothing. Only that we can calculate the wavefunction. Big deal, we know that, and that says nothing about whether MWI is true. The whole link is just irrelevant.
3. Has been reverted by multiple editors, even bots. --Michael C. Price ^talk 01:55, 7 February 2010 (UTC)

I note the bot has just kicked in again. --Michael C. Price ^talk 02:45, 7 February 2010 (UTC)

Reception

This section features a quote attributed to Stephen Hawking from a British television program.

... "In all these twitters and Universes of the Multiverse are they as real as this one seems to be to me?" Cut to footage of Hawking and Campbell. Hawking says "Yes. [pause, Campbell looks stunned; Hawking continues] According to Feynman's idea, every possible history and ken is equal real. It is just that some histories are more probable."[72].

"Twitters" and "ken"? I first assumed this was vandalism but it turns out that the original edit was made on 29 January 2010 by user Hunter2005 and includes the same quote. This shows when the edit was made:

http://en.wikipedia.org/w/index.php?title=Many-worlds_interpretation&diff=340707895&oldid=340631962

The link in the footnote is dead (http://www.windfallfilms.com/productions/production-details/reality-rocks.html)- archive.org shows the website did exist but the interview is not accessible.

However, the show is on YouTube - http://www.youtube.com/watch?v=S3aadgf0GH8&feature=related - the relevant section starts at 2:58. He definitely doesn't say twitters!

What Hawking says in reply is "Yes. According to Feynman's idea, every possible history of Ken is equal (sic) real". "Ken" is the guy who is interviewing Hawking: Ken Campbell.

Assuming that Hawking's statement is important enough to be included in the article, I think the quote needs to be tidied up a bit. At the moment it's a mess. Pinglis (talk) 10:13, 28 April 2010 (UTC)

An earlier editor seems to have misheard "trillions" as "twitters". I moved most of the dialogue into the reference string -- it seems to easy to summarise. --Michael C. Price ^talk 11:36, 28 April 2010 (UTC)

The section is ridiculous

Quantum suicide Main article: Quantum suicide There is a rather more dramatic test than the one outlined above for people prepared to put their lives on the line: use a machine which kills them if a random quantum decay happens. If MWI is true, they will still be alive in the world where the decay didn't happen and would feel no interruption in their stream of consciousness. By repeating this process a number of times, their continued consciousness would be arbitrarily unlikely unless MWI was true, when they would be alive in all the worlds where the random decay was on their side. From their viewpoint they would be immune to this death process. Clearly, if MWI does not hold, they would be dead in the one world. Other people would generally just see them die and would not be able to benefit from the result of this experiment.

This is some of the stupider shit I have seen on Wikipedia. Just because something is low probability doesn't mean it is impossible! Plus it has no cites and I can't imagine an actual physicist would say something like this. I'm deleting it if others agree.

Delete it, not just because it's quite possibly the dumbest thing I've ever read in my life, but because it betrays a complete misunderstanding of the multiverse theory (your consciousness is not at all a special property from the perspective of physics, and there's no reason to assume that you'll be lucky enough to follow only those paths through the tree of universes where you don't die), and lastly because it's not cited. As far as we know, some guy just wrote it and he's the only person in the world who thinks this idea is worth writing down anywhere, let alone in something that purports to be encyclopedic. Please delete away. Birge (talk) 21:24, 13 October 2010 (UTC)

You know what, I'm just going to delete all mention of Quantum Suicide. It's bad enough there is a page about it, but if it's valid metaphysical speculation for the "philosophers" it's completely out of place in a physics page, as it's certainly an untestable theory by anybody other than a subjective individual. That makes it, by definition, out of the domain of science since it's not replicable by others. Birge (talk) 21:32, 13 October 2010 (UTC)

Max Tegmark talks about it. Morbid... but it's nice to see someone giving the poor cat a break. It shouldn't say there's anything special about consciousness, or that any particular path is "followed". In the infinite number of universes where the experimenter doesn't just-so-happen to die, they'll either win a Nobel Prize or start their own Jackass franchise. Maybe I should read it... it can be cited however.—Machine Elf 1735 (talk) 22:29, 13 October 2010 (UTC)

How about addressing my statement that it's not even remotely scientific, as it's completely untestable? Furthermore, it is arguably nonsensical. There is an implicit assumption that your consciousness can only follow paths where you're not dead. This is analogous to saying your consciousness can only follow paths where you're conscious. Anybody who's been under general anethesia can attest that they've experienced paths where they were not conscious for a while. How much debate does one need before we can get rid of this? If somebody decides to write "Howard Stern rules!" on this page, is Michael C. Price going to insist we debate this for months before deleting it? I'd argue that the quantum suicide idea is equivalent in its apparent ludicrousness. Is it fun speculation? Maybe. Is it science? By definition, absolutely not. If nobody deletes this, it will be a perfect example of why Wikipedia is often accused of being not trustworthy or a serious source. Birge (talk) 22:27, 23 October 2010 (UTC)

How about arguing it over at the quantum suicide article? --Michael C. Price ^talk 03:22, 24 October 2010 (UTC)

LOL, what was I thinking, of course it has it's own article, in addition to one for fictional use. The text of the lead there would be an improvement to the remaining text here. I completely agree the removed text was very misleading and ridiculously sensational.—Machine Elf 1735 (talk) 17:32, 25 October 2010 (UTC)

Lead is obscure

IMO the current lead is obscurantist. Text such as

"all projectable future states of particles can be considered real and part of the "world" (or "universe") of the particle, even though there are many possible and deterministic alternatives allowable via quantum uncertainty and indeterminacy."

in the first paragraph is not helpful to the general reader. --Michael C. Price ^talk 16:00, 12 July 2010 (UTC)

I disagree. The current text "asserts the existence of the wavefunction, but denies the reality of waveform collapse" is itself so obscure as to mean little or nothing "to the general reader." My intro at the very most says what it actually is. -Stevertigo (w | t | e) 16:10, 12 July 2010 (UTC)

So is the collapse explanation, especially since it was all linked. The question is, which is more accessible?

Let's examine the proposed statement:

that all projectable future states

Eh? Projectable? Means nothing. A link or two would be helpful here.

of particles

Real particles, virtual particles? Ghost particles? What about fields?

can be considered real

Can be? Yes, or no? This is just technobabble padding. "can be considered" is prohibited by the MOS.

and part of the "world" (or "universe") of the particle,

Eh?

etc etc

--Michael C. Price ^talk 16:24, 12 July 2010 (UTC)

Firstly, you appear to concede that the extant formulation is inaccessible. If so, that means we can move on to working on something that works. You wrote: "So is the collapse explanation, especially since it was all linked. The question is, which is more accessible?" - What "collapse explanation?" In your line-by-line retort:

1 "Eh? Projectable? Means nothing. A link or two would be helpful here."

"Projection" does mean something, and I agree that a link or two is warranted.

2 "Real particles, virtual particles? Ghost particles? What about fields?"

Understanding of field-particle duality is assumed. The issue with using "particle" instead of something like a cat is that the theory has actual functional application at the small scales than at large ones, and therefore its relevance is one confined to particle physics. Your criticism is one directed more toward the inherent problems with regarding everything as a "particle," and I agree with it.

3 "Can be? Yes, or no? This is just technobabble padding. "can be considered" is prohibited by the MOS."

It was previously "must be." I changed that because a theory is not an activist promotion, it simply suggestive of a new way of looking at the issue. In other words one can see something like time as relativistic, but even in rigorous context we cannot say they must see it that way.

4 "part of the "world" (or "universe") of the particle," Eh?

You are right with this one, and I went to bed with a mental note to fix this, which essentially requires a rewrite. Good catch.

5 etc etc

What "etc?" -Stevertigo (w | t | e) 20:14, 12 July 2010 (UTC)

PS: The current version reads:

Many-worlds is an interpretation of quantum mechanics that asserts the objective reality of the wavefunction, but denies the reality of wavefunction collapse. It is also known as MWI, the relative state formulation, Everett interpretation, theory of the universal wavefunction, parallel universes, many-universes interpretation or just many worlds.

Which, Im sure you agree, is inadequate. -Stevertigo (w | t | e) 20:26, 12 July 2010 (UTC)

No, I do not agree that the old intro was inadequate. The problem lies in your statement "Understanding of field-particle duality is assumed." You are making a lot of assumptions about the reader, which are false, since most readers do not understand field-particle duality. All the talk about particles is unnecessary, and just obscures the message.

The current lead:

asserts that all imminent future states of particles can be considered real —each representing a possible "world" (or "universe") of deterministic alternatives —even though there are many allowable possibilities according to quantum uncertainty and indeterminacy.

can be reduced to:

asserts that all possible futures are real —each representing an actual "world" (or "universe")

without loss of content.

--Michael C. Price ^talk 22:29, 12 July 2010 (UTC)

Michael, you wrote: "You are making a lot of assumptions about the reader, which are false, since most readers do not understand field-particle duality. All the talk about particles is unnecessary, and just obscures the message." - So am I to understand that you think (notation mine) "..asserts the [[Philosophical realism|objective reality]] (easter egg to philosophical concept) of the wavefunction (a QM math tool), but denies the reality of wavefunction collapse (a QM paradigm)" is writing that is "accessible" to "most readers?" -Stevertigo (w | t | e) 02:47, 13 July 2010 (UTC)

Since you have not responded to my substantive point, about trimming unnecessary verbiage, I assume you accept the point of effective writing, that "less is more". In answer to your question, I thought the previous lead was adequate since it was adjacent to a prominent graphic with an explanation of how it pans out in the schrodinger cat case. But in the spirit of comprise I've added your reduced description to the lede as well.--Michael C. Price ^talk 05:38, 13 July 2010 (UTC)

Good and "effective" writing is not mostly about "trimming unnecessary verbiage" - it cannot be done without expertise, and in any case writing should be about explanations, and not about one-sentence leads that don't actually say anything about what it is. So, if you can think about it, what is the "many-words" theory exactly, in just one long sentence?

I appreciate your wanting to find consensus here. You should note though that your issue with the word "particle" means that the current wording

"denies the reality of wavefunction collapse, which implies that all possible futures are real —each representing an actual "world" (or "universe")"

...doesn't actually make sense, because the real scope of the interaction is quantum (not cat) and therefore, colloquially, regarding a particle (not cat), and the "worlds" or "universes" refers the those particles' various possible future-states —which are also generally described as particles (not cats). -Stevertigo (w | t | e) 15:46, 13 July 2010 (UTC)

Actually good and "effective" writing is mostly about "trimming unnecessary verbiage". But leaving that aside, I don't get your explanation about what particle adds to the description. You're saying "everything's a particle, so we must mention them". I'm saying that "everything's a particle, so we don't need to mention them". The particle content is not what distinguishes MWI from the alternatives; it's the lack of wavefunction collapse that does that.

A single, one sentence description: "All possibilities are realised."

--Michael C. Price ^talk 17:08, 13 July 2010 (UTC)

You can't be seriously _____ that ____ words ____ better ______. The art of writing is not a deletionist concept - its a constructionist one. There is some legitimacy in the idea that certain things which are deemed superfluous don't need to be included, but you have yet to make a case for why certain writing (particularly regarding the particles) is superfluous. By raising the issue of removing unnecessary words, perhaps you better mean removing unnecessary concepts. I construct writing from the ground up based on what I think needs to be included, and later I do in fact trim out anything which might present too much information, or what might belong in a secondary or tertiary sentence. I disgree with the absolute reductionist approach because its often too compact and non-explanationist. All that said, I greatly appreciate the line-by-line approach, and think it works well to isolate issues and controversies. So Im glad that were making progress.

The issue of particles is difficult. I dislike the term myself, but that is of course the term that physicists use, to refer to absolutely anything of dimension. The standard model idea of "force particles" for example is a kludge, or perhaps better said as a misnomer for a 'localization and quantification of force.' In that context, your issue of being more specific - "which particles" - is well made. But I don't know how we can decide the issue here, since ultimately Many-worlds is about time and how IRL looks from a holographic perspective. Referencing the anyon specifically might work, but that would require dealing with holography, not to mention correspondence — which on face value might be not what the "general reader" can deal with. -Stevertigo (w | t | e) 17:42, 13 July 2010 (UTC)

I don't really want a debate here on effective writing, but last time I checked policy it endorsed similar sentiments - and if you go on courses for such things (and I speak from experience) they will say the same, viz the art is to cut ruthlessly (and that means both words and concepts).

Back to particles and we see the problem with talking about them, since particles probably aren't fundamental entities a la string theory. (You mentioned correspondence in this regard.) Many-worlds is not dependent on the latest TOE; by mentioning particles (or p-branes) we are tying it to an outmoded (or speculative) model of reality. We should just excise the whole concept from the lead (and article).

--Michael C. Price ^talk 20:51, 13 July 2010 (UTC)

The "less is more" argument only goes so far, and while there may be certain competitive aspects to editing, "ruthless"ness is not a virtue in any context and never leads to anything good. We work toward consensus, not ruthlessness.

I disagree with the idea that the concept of a "particle" is so strange as to be entirely foreign to common speakers. Rather I think the opposite: It's about the only term we can use to confine MW to the scope of quanta (other than "quanta" itself) that has both common and theoretically advanced definitions. Whether these meanings are truly orthogonal with each other depends entirely on the reader and how much they understand concepts like wave-particle duality. (Good writing works for both, and gives just a flavor of the more advanced definition to the novice). Again I find it entirely ironic that you oppose the concept of the particle, considering your support for the previous wording which was vastly more obscure. I will agree to dealing with more precise terms but only as a parenthetical to augment the meaning of "particles." -Stevertigo (w | t | e) 23:33, 13 July 2010 (UTC)

We seem fated to talk at cross-purposes.

Ruthless editing applies as much to one's work as others' - it has nothing to do with competitive editing.

I have no idea where you got the idea that the concept of a "particle" is so strange as to be entirely foreign to common speakers. My points were that the concept is 1) irrelevant to MWI and 2) not fundamental. Hence to be avoided here.

--Michael C. Price ^talk 02:11, 14 July 2010 (UTC)

"..fated to talk at cross-purposes" - I don't think so. I raised the issue of improving the lead, and you agreed with that. You raised the issue of particles and I'm agreeing with you in part. Furthermore any two people are different and not necessarily of crossed "purposes."

"My points were that the [particle] is 1) irrelevant to MWI and 2) not fundamental." - What would you say is the "fundamental" unit of dimension, ie. a fundamental object? Would you say that MWI is irrelevant to physics? Continuing in that vein, would you say that particles are irrelevant to particle physics? The issue is that even in the graphic, as well as in the usage of the terms "worlds" and "universes," the actor in the given model is always some kind of macroscopic object (like a cat). In reality the manifest effects of MWI are only macroscopic in the sense of deterministic outcome, and its better to use the particle model. Its not about causality and ultimate effect, rather its about particles in a holographic dimension which have certain statistical interactions with the higher dimensional form.-Stevertigo (w | t | e) 22:02, 15 July 2010 (UTC)

Yes the graphic illustrates a cat splitting because

1. that is easy to illustrate,
2. is sourced (DeWitt used a similar graphic and so did John Gribbin).

But more fundamentally, MWI is a macroscopic effect. When a cat splits, it splits irreversibly; down at the subatomic level there is no irreversible splitting, it's all just a mesh of sum over histories of p-branes, strings, point particles or whatever. It's only when you scale up that thermodynamic effects (such as decoherence) arise, and worlds or timelines can be said to have diverged.

What would you say is the "fundamental" unit of dimension, ie. a fundamental object? I have no idea, and am content to await the TOE before I decide.

--Michael C. Price ^talk 22:17, 15 July 2010 (UTC)

MP wrote: "MWI is a macroscopic effect." It isn't. The only way parallel universes actually exist is as holographic echoes. There is no serious way to claim that a massively multidimensional object (like a cat) can be corresponded in the way that that makes MWI a macroscopic theory. The macroscopic effects idea contradicts the sublime insight of MWI. There is no superposition of deterministic states or sum over histories except at the holographic level and at scales which defy a naive macroscopic perspective.

MP wrote: "I have no idea [what is the "fundamental" unit of dimension, ie. a fundamental object], and am content to await the TOE before I decide." - We can't wait on a "TOE" - in any case it takes decades for any theory to creep up on people. But consider how a high-level physicist uses the term "particle" - its often quite multimentional - and thus not as simplistic as you claim it to be. What do you think of the word "quanta?" -Stevertigo (w | t | e) 00:20, 16 July 2010 (UTC)

I have no idea of why you say that the holographic principle is required. MWI predates the holographic principle, and it not dependent on it. MWI is simply the superposition principle appled to everyday objects.

Quanta come from the Einstein-DeBroglie observation that

$p_{u}=i\hbar d/dx^{u}$

--Michael C. Price ^talk 04:32, 16 July 2010 (UTC)

Bohm's conjecture (holographic paradigm) is the relevant concept here and that far predates MWI. I disagree that MWI "is simply the superposition principle." Thats a bit simplistic, and I'm sure others would disagree with it. -Stevertigo (w | t | e) 19:15, 16 July 2010 (UTC)

Now I see why you're so interested in particles. They are core to Bohm's interpretation, but not to Everett's (who referred to MWI as the "pure wave theory" by contrast).

PS Bohm's holographic paradigm does not "far predate MWI". There's only five years between them (1952/1957). --Michael C. Price ^talk 20:04, 16 July 2010 (UTC)

Yes, the "physical system" Everett says is "described completely by a state function $\psi$" that is "an element of a Hilbert space" would itself seem to be a "particle" of some kind. -Stevertigo (w | t | e) 01:06, 20 July 2010 (UTC)

Yes, $\psi$ forms a point in an infinite dimensional Hilbert space, especially in the MWI, that's true - the physical state is usually (e.g. Copenhagen interpretation) identified with rays in Hilbert space - but it is not a particle in the vernacular sense. That is to say, N-particle states are points in classical phase space (6N dimensions in a real-valued vector space) but fields in Hilbert space if we think of the Hilbert space as 3N dimensional complex-valued space, because the probability amplitude is smeared out. --Michael C. Price ^talk 05:05, 20 July 2010 (UTC)

I'm not at all clear (IANAP) on how a statistical picture of possible phases corresponds to a complex field of compact dimensions. The picture between 6N real and 3N complex spaces is pinched and hard to see - real space only corresponds to complex space via real points, unless.. hm. Note that probability smearing is probably just the result of looking at the picture from a lower dimension - in a higher dimension the smearing should have some kind of compound effect. -Stevertigo (w | t | e) 21:51, 20 July 2010 (UTC)

(deindent) This a point that deserves more clarification, either here or at universal wavefunction. Perhaps the link in the lead should be to universal wavefunction and not just wavefunction for starters. --Michael C. Price ^talk 03:16, 21 July 2010 (UTC)

---

IMO the current lead is obscurantist. Text such as

"all projectable future states of particles can be considered real and part of the "world" (or "universe") of the particle, even though there are many possible and deterministic alternatives allowable via quantum uncertainty and indeterminacy."

in the first paragraph is not helpful to the general reader. --Michael C. Price ^talk 16:00, 12 July 2010 (UTC)

I disagree. The current text "asserts the existence of the wavefunction, but denies the reality of waveform collapse" is itself so obscure as to mean little or nothing "to the general reader." My intro at the very most says what it actually is. -Stevertigo (w | t | e) 16:10, 12 July 2010 (UTC)

IMHO "asserts the existence of the wavefunction, but denies the reality of waveform collapse" statement is very intuitive. Undergrad level. And the "future states of particles" statement is grad level (AFAIK requires some understanding of QFT). --Dc987 (talk) 06:01, 27 July 2010 (UTC)

Ha. Whether an explanatory piece of writing is undergrad or grad level depends entirely on the what prerequisites the reader has under their hat. If well explained, even our average reader should have little problem with understanding the concepts - time, particles, holography, correspondences, etc. - but to actually have a picture of the wavefunction and its collapse is 'undergrad level' only if the undergrad is about year 3, and if someone grad level has given them a grad level picture as a prerequisite. ;) -Stevertigo (w | t | e) 03:00, 1 August 2010 (UTC)

Many-minds: Not as irrelevant as its single-sentence section suggests.

I don't like the current sentence about the Many-minds interpretation. Here's my beef: The many-minds interpretation was originally presented as an "interpretation" of the many worlds interpretation (in Loewer and Albert's "Interpreting the Many Worlds Interpretation"). Basically it was an attempt to make sense of the Everettian picture in a way that didn't open you up to certain really bad-looking objections. Standard many-worlds, as a deterministic theory, has no obvious way of accounting for the quantum mechanical probabilities, even though it is through experimentation suggesting that the world obeys these probabilities that we came to accept the quantum mechanical picture in the first place. The Many-minds interpretation adds an explicitly indeterministic feature to many-worlds, which allows it to avoid this problem. In the many-minds picture, (in addition to the wavefunction) there are non-physical minds which evolve stochastically over time in a way that (by design) corresponds to the probabilistic predictions of QM (minds don't enter superpositions, even when the brains they are associated with do). The many-minds view shares the advantages of MWI and can account for the probabilities. The only problem with the many-minds view is that it's totally, unforgivably insane.

I would prefer if the article (1) mentioned the trouble that MWI has accounting for the probabilities which are a central part of QM and (2) mentioned that, rather than merely having a similar-sounding name, the many-minds interpretation is very relevant to the MWI, since it factors into an argument against MWI: if the only way of getting the right results from MWI is to interpret it as many-minds, then, since many-minds is utterly preposterous, MWI is either false or equally preposterous.

The article, as it stands, is structured so bizarrely that I'm at a loss as to where an addition of this sort could even fit in. I'm also not sure whether such an edit would last, since it involves a non-scarcrowified objection to the MWI, something conspicuously absent from the article as it stands. ZRPerry (talk) 21:55, 13 August 2010 (UTC)

1. The article already mentions probability within MWI in some detail.
2. Many-minds has been abandoned by one or both of its founders. The theory is essentially "dead".
3. There is ambiguity about what many-minds means (it exists in two distinct forms).

For these reasons it is better discussed in its own article, with just a short non-judgemental summary here. --Michael C. Price ^talk 05:07, 14 August 2010 (UTC)

PS I agree that this article has a bizarre structure. Some of the sections don't really help the reader. I tried to remove them, but the consensus was "keep". --Michael C. Price ^talk 05:10, 14 August 2010 (UTC)

My bad timing, as the issue had just been sorted... But actually, I was hoping you might (a) clarify whether Many–Worlds is a meta–interpretation, an interpretation, or a number of different meta–interpretations and/or interpretations... and (b) comment if a suitably abstract "MWMI" would be Physics or Metaphysics or ? (in terms of Instrumentalism/Entity realism). Thanks—Machine Elf 1735 (talk) 15:51, 14 August 2010 (UTC) (φύσις amateur)

According to Everett, with whom I agree, MWI is a meta-theory and a theory. Whether you want to call that an interpretation is debatable. To be an interpretation suggests that we have some freedom to adopt other viewpoints, but I don't think we have - although all adherents to other interpretations would disagree, of course. --Michael C. Price ^talk 18:01, 14 August 2010 (UTC)

---

Could someone clarify for me, isn't Many Worlds a meta–interpretation? Apart from the many franchises, isn't there a version abstract enough to permit probabilities to be calculated with whatever run of the mill math is accompanied by a straight face? If MWI is untestable (?) but addresses the paradoxes in a more logically salubrious way than alternatives, is it Physics?

Of course, the ontology is always sensationalized, (Multiverse makes a four course meal of that though). I think adding even one mini mind is much more extravagant when, "by design", why not have magic QM corresponding eyeballs collapse your wave function? Besides, we'll want that mind busy jumping from world to world finding our lotto numbers.

Is there anything useful about MWI that isn't ruined by mini minds?—Machine Elf 1735 (talk) 05:12, 14 August 2010 (UTC)

Unmentioned Thought Experiment.

I don't know if this is original, but a quantum random bit generator's ASCII output would appear intelligent in some world-lines. Could there be religious objections to the many-worlds interpretation? —Preceding unsigned comment added by Mister Mormon (talk • contribs) 02:05, 14 November 2010 (UTC)

Criticism Section

This article appears to be heavily biased towards the MWI; there exists only a section addressing common objections to the MWI based on misconceptions. Perhaps the article would benefit from a return to neutrality in the form of a 'Criticism' section, which mentions some of the main objections to the MWI which aren't ill founded. 220.235.96.106 (talk) 03:20, 21 March 2011 (UTC)

Can you think of any? (And can you source them?) -- cheers, Michael C. Price ^talk 07:42, 21 March 2011 (UTC)

I strongly agree that the article is heavily biased towards MWI, and in particular the "Criticism" section does not accurately represent the whole range of published views on the subject. Just doing a random review of six books on quantum mechanics and its interpretations, I find that all six of them are decidedly NOT favorable toward MWI, and some of them are outright derisive. These books are by recognized scholars and experts in the field, so they ought to be accurately reflected in this article, regardless of whether we agree with them.AIMW32 (talk) 14:07, 31 August 2011 (UTC)

There isn't a section called criticism. 1Z (talk) 14:35, 31 August 2011 (UTC)

Right, the section is called "Reception", and the point is that the section (as presently written) is preposterously biased in favor of MWI. According to Wikipedia policy, the section needs to be evenly representative of the reputable sources and literature on this subject. Most of the reputable sources are decidedly not favorable to the MWI interpretation, but a reader of this Wikipedia article, as presently written, would never suspect this. So the section needs to be re-written to be more balanced and representative.AIMW32 (talk) 04:43, 2 September 2011 (UTC)

I do not call having informative responses to criticisms "preposterously biased". However, if in the interests of "balance" you wish to include quotations from the six books that "are are decidedly NOT favorable toward MWI, and some of them are outright derisive.", go ahead; it is true that many "experts" are derisive - and the fact of their derision is worth reporting - although whether they still form a majority is not so clear. -- cheers, Michael C. Price ^talk 07:15, 2 September 2011 (UTC)

Welcome to Wikipedia, I hope you like it here and decide to stay. Here are some guidelines:

1. WP:CITE your sources, don't just make it up.
2. Or at least, make it is plausible. You did not find that most "scholarly literature on quantum mechanics and its interpretations" WP:DONTLIKE MWI from your "cursory" survey.
3. And see WP:OR before embarking on an extensive survey. It won't get any traction either. Cite one from an WP:RS.
4. Try to resist editorializing, but honestly, if you want to say MW-haters talk a lot of smack, I don't think that's likely to be challenged.—Machine Elf ¹⁷³⁵ 09:50, 2 September 2011 (UTC)

Specific conditions of time travel.

Regardless of artificial or natural time travel claims, if time travel (wormholes) exists then parallel realities precisely make sense period. —Preceding unsigned comment added by 196.20.160.72 (talk) 09:13, 31 March 2011 (UTC)

The "Reception" Section

As mentioned above, I think the section on "Reception" needs to more accurately reflect the available reputable sources. Here is the kind of section that I think would be appropriate and representative of the views of the scientific community.

Reception

From the beginning, the response to the many worlds interpretation of quantum has been quite varied. Hugh Everett’s thesis advisor, John Wheeler, originally looked favorably on the idea, but in later years withdrew his endorsement. In an interview in 1986 Wheeler said “I supported this to begin with, because it seemed to represent the logical follow-up of the formalism of quantum theory. I have changed my view on it today because there's too much metaphysical baggage being carried along with it, in the sense that every time you see this or that happening you have to envisage other universes in which I see something else happening. This is to make science into a kind of mysticism.” Also, when (at Wheeler’s urging) Everett visited Neils Bohr in Copenhagen in 1959, hoping to convince Bohr of the soundness of the idea, Bohr and his circle reacted very negatively, even derisively. (This may have contributed to Wheeler’s loss of confidence, since he was a great admirer of Bohr.) Bohr's close colleague, Leon Rosenfeld, wrote in 1959 after meeting with Everett “This work suffers from the fundamental misunderstanding which affects all attempts at ‘axiomatizing’ any part of physics. The ‘axiomatizers’ do not realize that every physical theory must necessarily make use of concepts which cannot in principle be further analyzed. … The fact, emphasized by Everett, that it is actually possible to set-up a wave function for the experimental apparatus and a Hamiltonian for the interaction between system and apparatus is perfectly trivial, but also terribly treacherous; in fact, it did mislead Everett to the conception that it might be possible to describe apparatus + atomic object as a closed system. … This, however, is an illusion.”

In his book "Particles and Paradoxes, The Limits of Quantum Logic" Peter Gibbins remarks that the MWI "is taken very seriously by a few physicists and philosophers, and not at all by most others", and he follows this with a review of the range of criticisms.

Similarly in “The Structure and Interpretation of Quantum Mechanics”, R. Hughes says the MWI has been subjected to each of four types of criticisms: "(1) the internal consistency of MWI can be challenged, (2) it's philosophical coherence can be doubted, (3) one can object to the lack of fit between MWI and other physical theories, and (4) one can critize it on general methodological grounds." In particular Huges discusses what he regards as a problem concerning the lack of a valid probability measure for the outcomes of events. He says that those who contend MWI solves the measurement problem typically imagine that the probability distribution for the various possible outcomes of a sequence of quantum events can be associated with the relative number of future “worlds” that contain one set of outcomes versus another, but according to Huges there is no suitable principle of individuation to distinguish “worlds” in such a way that their relative numbers can be "counted" in any statistically meaningful sense. He concludes that the MWI does not provide us with any new understanding of the measurement process, because each observer is still faced with the dualism that the interpretation sought to eliminate. The only difference is that any "apparent" transition not governed by the Schrodinger equation "is now accompanied by an ontological cloudburst beside which the original modest dualism of von Newmann looks unremarkable, if not pusillanimous".

Euan Squires has written that "the general view of the theoretical physics community has been to reject the many-worlds interpretation...[although it] has become more fashionable in recent years". After reviewing again the problem of a lack of a suitable probability measure, Squires sums up his view as follows: "The many worlds interpretation of quantum theory only makes sense if some notion of selection, generally at random and probably associated with consciousness, is added to the theory."

Likewise, Roger Penrose comments : "It seems to me a theory of consciousness would be needed before the many worlds interpretation can be squared with what one actually observes... Claims have been made that the 'illusion' of [quantum jumps] can, in some sense, be effectively deduced in this picture, but I do not think that these claims hold up. At the very least, one needs further ingredients to make the scheme work. It seems to me that the many worlds view introduces a multitude of problems of its own without really touching upon the REAL puzzles of quantum mechanics."

Alistaire Rae’s response to the MWI was also negative. He wrote : "The idea of a near-infinite number of universes which can never interact with each other and whose existence can therefore never be verified seems to most scientists to be an extreme breach of this principle [of economy] and certainly greater than that implied by the de Broglie-Bohm hidden-variable theory." Rae goes on to say "In recent years a combination of “many worlds” and subjectivism has been suggested. This proposes that there is no collapse, the wave function evolves according to the time-dependent Schrodinger equation, and that is all there is in the physical universe. However, we conscious observers are incapable of seeing the world this way; it is in our nature that we can be aware of only one result of any measurement process so, although the others are still out there, we are unaware of them. One of the problems that this approach gives rise to is to explain how different conscious observers always see the same results, and indeed it has been suggested that this points to all our consciousnesses being linked to some 'universal consciousness', one of whose jobs is to see that this agreement occurs!"

J. C. Polkinghorne has this to say : "[In MWI], entities are being multiplied with incredible profusion. Such prodigality makes little appeal to professional scientists, whose instincts are to seek for a tight and economic understanding of the world. Very few of them, indeed, have espoused the Everett interpretation. It has, however, become more popular with what one might call the 'Gee-whizz' school of science popularizers, always out to stun the public with the weirdness of what they have to offer... Reality is not to be triffled with and sliced up in this way."

Huw Price has written "...quantum cosmologists have become enthusiastic supporters of the no-collapse view... Philosophers have been rather less enthusiastic, and there are a number of astute critical studies of the no-collapse proposal in the philosophical literature on quantum mechanics. One [criticism] that is well-recognized by the view's proponents is... the issue as to why the many-branched reality it envisages should appear classical... but I want first to draw attention to a problem which seems not to be recognized at all by the proponents of the no-collapse view... It concerns the notion of probability in a model of this kind." Price then goes on to recount the problem discussed above, pointing out the lack of a suitable probability measure. He also comments that the task of critiquing MWI is complicated by "the fact that the interpretation is ill-defined in a number of crucial respects (among them, the issue of what, if anything, actually 'splits')."

David Wick writes: "Many-worlds go, in my opinion, beyond the reasonable and into science fiction... Contemplating all possible worlds suggests hubris but is philosophically respectable; claiming that they all co-exist is not."

In a series of interviews with prominent quantum physicists in 1986, including John Bell, John Wheeler, John Taylor, and David Deutsch, the first three spoke negatively about MWI, and even Deutsch (regarded as a well-known proponent of MWI) conceded that “I now think Everett was slightly wrong.” According to Deutsch, Everett thought that his interpretation followed directly from the formalism of quantum mechanics, but Deutsch believes that “even in his interpretation, one requires a little bit of extra structure in order to arrive at the interpretation… it is the little piece of mathematics which provides the connection between the wave function… and the concept of the many parallel universes. I don’t think one can do without this extra structure”. Deutsch agrees that this “little bit of extra structure” is needed “to tell us something about how any individual universe in this vast stack of cosmic alternatives fits into the stack”. Furthermore, Deutsch believes Everett was wrong to claim that MWI is empirically indistinguishable from the other interpretations. Deutsch contends that quantum mechanics under the MWI is not empirically equivalent to conventional quantum mechanics, because he says a sufficiently sensitive consciousness actually would perceive a superposition of universes – just as many critics of MWI have always asserted. He said “If we had fine enough senses, then we could detect or feel (whatever that would mean) the presence of the other universes”, and he suggests that it may become possible to test this with artificial intelligence devices within a few decades.

John Bell, although saying the the MWI had “some merit”, did not view it favorably. He said “I have strong feelings against it… it’s extremely bizarre, and for me that would already be enough reason to dislike it. The idea that there are all those other universes which we can't see is hard to swallow. But there are also technical problems with it which people usually gloss over or don't even realize when they study it. The actual point at which a branching occurs is supposed to be the point at which a measurement is made. But the point at which the measurement is made is totally obscure. The experiments at CERN for example take months and months, and at which particular second on which particular day the measurement is made and the branching occurs is perfectly obscure. So I believe that the many-universes interpretation is a kind of heuristic, simplified theory, which people have done on the backs of envelopes but haven't really thought through. When you do try to think it through it is not coherent.”AIMW32 (talk) 16:03, 3 September 2011 (UTC)

Thanks for doing all this. One thing that worries me here is that the Bell quote seems to be talking about something different from MWI as it is described in this article (he seems to be talking about a form of MWI in which measurements have special status and branching is instantaneous). The same may be true of some of the other quotes. (I'm not sure what to do about this - I just wanted to point out the problem.) --Zundark (talk) 12:12, 4 September 2011 (UTC)

Bell was reacting to early work by Everett. Ideas of decoherence came later. 1Z (talk) 18:10, 4 September 2011 (UTC)

I agree that there is some difficulty here, due to the fact that, at various times, various people have expounded various concepts, all of which are commonly grouped under the header of "the many worlds interpretation", and it's difficult to talk about the "reception" of all those ideas in a single article. This goes back to the very beginning, because one could say DeWitt (after his brief initial opposition) quickly became a supporter of Everett's interpretation, and yet, as many people have pointed out, the interpretation that DeWitt described was not identical to what Everett described. Likewise the people who regard themselves as proponents of "many worlds" today usually have in mind some particular vairant that is different from both the Everett and the DeWitt conceptions. For example, as noted above, Deutsch says Everett was wrong to believe that a viable interpretation arises purely from the formalism of quantum mechanics, and he (Deutsch) now agrees with many of the critics of Everett who always insisted that some additional feature was needed to even have a coherent interpretation. Furthermore Deutsch believes a sufficiently sensitive observer actually WOULD sense the superposition of worlds, which Everett (and many current proponents of "many worlds") would vociferously deny. So is it correct to count Deutsch as a supporter of Everett's interpretation, or as a critic and debunker of it?

Despite the fact that many of the scientists I quoted above were addressing variants of "many worlds" that differ from the variant that is espoused by the "owners" of this Wiki article, all these scientists were giving their reaction to what had been presented to them as the "many worlds" interpretation, so I think this is legitimately part of the "reception" of many worlds. Maybe the best that can be done in this article would be to preface the "Reception" section with an explanation that a variety of ideas related to "many worlds" have been proposed, some differing from each other in significant ways, and this section surveys the reception of this whole class of ideas. In many cases, those who espouse one particular variant of "many worlds" actually agree with the criticisms of the other variants, even though (of course) they believe the criticisms do not apply to their own preferred variant.AIMW32 (talk) 15:38, 4 September 2011 (UTC)

If a notable source says "many Worlds", that should count for Wikipedian purposes. WP should not filter, although it may contextualise (see below) 1Z (talk) 18:10, 4 September 2011 (UTC)

I think it would be better to "stick to physics" and don't give too much weight to opinions of people, and instead explain the detailed mathematical arguments that have been published in physics journals. E.g. we can explain Deutsch's thought experiment that demonstrates how exactly one could in principle experimentally falsify the Copenhagen interpretation. Count Iblis (talk) 15:49, 4 September 2011 (UTC)

I disagree: There is endless complaint about physics articles being too dry and technical here.1Z (talk) 18:10, 4 September 2011 (UTC)

Agree with 1Z, we are not here "just" to report the science, but also to report on the response to the theory, place it in context etc etc. -- cheers, Michael C. Price ^talk 21:48, 4 September 2011 (UTC)

Hmmm... a "reception" section (which is fairly standard to be included in an article of this kind) is basically intended to report the views, expressed in reputable published sources, of scientists, giving a representative indication of how the subject theory has been received within the scientific community. This consists of reporting and/or summarizing the published views of a representative sampling of recognized experts in the field. I don't think it would be appropriate to suppress this information in the present article, even if some editors here don't agree with how the scientific community has viewed the subject. We have to guard against constructing a novel narrative, i.e., cherry picking published claims with which we (certain Wiki editors) agree, and suppressing the published reaction to those claims within the scientific community. For example, when you say above that Deutsch's thought experiment "demonstrates" how one could in principle falsify Cophenhagen, you seem to think this is somehow definitive and nothing more need to be said, whereas in fact there is nothing like universal assent to Deutsch's claims within the overall scientific community (nor even within the many-worlds community). The criticisms expressed by many scientists are precisely aimed at the claims of people like Deutsch. So, although I agree with you that the article should explain Deutsch's claims (noting that they contradict the views of Everett, et al), I don't think this obviates the Reception section.AIMW32 (talk) 16:18, 4 September 2011 (UTC)

My apologies for not suggesting WP:NPOV as well. It's difficult to be objective, sometimes it's only possible collectively, and that can look a lot like mistakes from a subjective point of view (WP:AGF). Still, your version would be the obvious example of "cherry picking" (even flippant remarks) with no real effort to represent a competing point of view. It self-consciously repeats purported faults needlessly, hanging a lantern on the disproportionate number of negative assessments given (vs. zero positive) which must seem absurd.

While it does allude to the possibility of outdated counter-examples, the backhanded concession is spoiled by inaccurately stating the reaction to MW from "the beginning" has been "quite varied". The initial reaction was emphatically negative, it was ridiculed and summarily dismissed, as was Everett: "undescribably stupid and could not understand the simplest things in quantum mechanics" [sic].

It goes out of its way to paint MW's advocates as opponents by misrepresenting qualified merits as unqualified defects or something of a renunciation and mia culpa. (It would need to provide more citations, not fewer, when contradicting other statements in the article; generally, anything likely to challenged should be cited. Also, the citations are inadequate; consider using citation templates, Template:cite, and please provide a page number where possible).

As was noted, it fails to distinguish between the various "theories" which have been associated with MW. It characterizing them all by the earliest versions or far-fetched attempts to fix it like "many minds", presumably the proper topic of several comments. However, these are portrayed as requirements of any MW interpretation, implying some kind of unscientific mystical (or otherwise disembodied) selection must be made.

Generally, the context of remarks is omitted, in effect, making it seem like other interpretations make better predictions ("selections") or anyway, that they make them at all. Perhaps the sources in question do mistakenly believe that MW doesn't use the square of the wave function, or that it dispenses with the wave function entirely. An accurate description is presented elsewhere in the article and its reception is not about what people mistakenly say it says. On the other hand, an "ontological cloudburst" is notably florid and stunningly wrong headed vis-à-vis hidden variables. In so far as the apparently metaphysical objection would be hypocritical, it may argue that some non-metaphysicists should "shut-up and calculate", foregoing a naïve appeal to Occam's razor, (i.e., instances of "world" count but instances of "particle" do not). But though interesting, it's not so much about MW's reception per se, it's about the irrationality of an individual's reaction, despite being a physicist (presumably).

Further, as an alternative to Copenhagen's fictional "collapse" (now recognized as philosophical dogma), MW provided an objective explanation of a subjective scenario. This is mischaracterized as the introduction of subjectivism by MW, rather than its refusal to ignore the issue. In so far as the fiction is science, similar charity is denied MW, because realism is not incompatible (another amateur foul vs. the null doxa; I don't think scientists should worry too much about paradox but MW is a philosophical slam dunk).

My advice would be to focus on how sources say it's been received, including the competing point of view.—Machine Elf ¹⁷³⁵ 23:31, 4 September 2011 (UTC)

The sampling of comments on MWI that I gave above was not cherry picked. I honestly grabbed – quite indiscriminantly - every book I could lay my hands on that said anything on the subject, and wrote down what they said. I didn’t choose the sources based on whether they were favorable or unfavorable towards the MWI. It just so happens that they were all unfavorable (with the partial exception of Deutsch’s comments, but he was arguably advocating something different from what this Wiki article describes as MWI). Nothing I can do about it, other than go hunting for more books that discuss the relative merits of various interpretations of quantum mechanics, and try to find some that view MWI favorably. It's true that some of the references I cited were from a time prior to when "decoherence" began to be cited by proponents of MWI in response to certain kinds of criticisms, but not all of them were.

By the way, the existing article doesn't seem to directly address the issue of whether MWI solves or elucidates the measurement problem. The Wiki article on decoherence says specifically that it does not, and includes external links to references defending that poition. Since this is evidently a controversial point, and a very important one, I think this article should contain an explanation of how the proponents think MWI elucidates the measurement problem, and also why critics think it does not.

One other comment/question: Is the image that appears at the top of this article, showing a little film strip of Schrodinger’s cat splitting at the point of decision into a live cat and a dead cat, really representative of how the proponents believe MWI works? If so, then they ought to accept criticisms of this version of MWI. If not, the image ought to be replaced with one that depicts an interpretation that the proponents are willing to defend.AIMW32 (talk) 16:45, 5 September 2011 (UTC)

I'm sure you see can see that the effort did not comply with WP:NPOV. Keep WP:SYN in mind with regard to “he was arguably advocating something different from what this Wiki article describes as MWI”. So he's not what you'd call a “proponent”… You're really going to need complete citations and you'll want to make them as easy as possible to verify by including page numbers. If you can't do anything about it, try something you "can" do… Maybe you should think about integrating smaller, fully-cited edits, into the existing material? It's not just going to go away… but that's a good thing. It saves you from having to "find" up-to-date sources "cited by proponents of MWI" ahem "in response to certain kinds of criticisms".

I wasn't aware the measurement problem could be solved, (or that elucidation expires). Hopefully, the physicists will review the claims being attributed to MWI over at decoherence. From your description, apparently it should be at measurement problem?

A picture of Schrödinger's cat means “the proponents” of MWI are here on WP and “so, then they ought to accept criticisms of this version of MWI.” Or… say goodbye to Mr. Quarkibottoms?!? Yikes, they can't say you didn't warn them.—Machine Elf ¹⁷³⁵ 19:53, 5 September 2011 (UTC)

It's been suggested that perhaps some of the references I quoted above were a bit out-dated, so I decided to do a google book search on "interpretations of quantum mechanics" and randomly select a relatively recent work on the subject, and report what they say about "many worlds". The top reference was "Foundations and Interpretations of Quantum Mechanics" (2001), which is a 981 page survey of all the interpretations, by Auletta and Parisi. The chapter devoted to Many Worlds concludes as follows:

"In conclusion, on physical and metaphysical grounds, MWI as a whole is not a sound theory because it does not overcome the greatest problems with which the QM theory of Measurement is faced, while posing many unanswerable questions. Its main weakness is that it does not consider the Measurement theory as a basic aspect of every physical theory, and particularly of QM, due to the peculiar problems that it poses."

I suppose we can go on collecting published views from reputable sources on the subject, and I'm sure some favorable to many worlds will turn up, but I think it's fair to say, based on what I've seen so far, that many worlds is not well regarded by most experts on interpretations of quantum mechanics. If that's true, then the article needs to reflect that fact.AIMW32 (talk) 20:48, 5 September 2011 (UTC)

When a source is on Google Books, provide the link so it's easy for people to verify. You can link directly to page or to a search within a book. You don't provide the page number, and searching through 981 pages is no one's idea of a good time. Page 251… here it is in a citation template:

<ref name="AulettaParisi2001">{{cite book |first=G. |last=Auletta |first2=G. |last2=Parisi |year=2001 |title=Foundations and Interpretation of Quantum Mechanics: in the light of a critical-historical analysis of the problems and of a synthesis of the results |publisher=World Scientific |isbn=9789810246143 |url=http://books.google.com/books?id=lSAfY0LEKBMC&lpg=PA251 |page=251}}</ref>

And here it is live with the quote immediately preceding your selection.

References

They gets them a hankering to maintain a statistical value for the entire universe, tho admitting it's utterly ridiculous; they take charge, and deny the use of the wave function for "very big systems", and absolutely forbid it to be used by the universe. Never mind the disingenuous hankering for "very big systems" on which to "maintain some statistical value", they don't believe the wave function was involved in the big bang… for example… "because it is impossible—even in principle" not merely ridiculous from a human perspective. MWI won't deliver miraculous copies of the universe, collated and stapled. I bet it can't even fax a globular cluster.

I think it's fair to say you could go on selecting these remarkable anecdotes, but there's no virtue in randomly choosing sources, and you could select both favorable and unfavorable ones used in the article, anytime you please. WP:SOAP You may have mentioned your strongly held opinion repeatedly; it seems well established. I was rather hoping you'd explain your intentions regarding the cat.—Machine Elf ¹⁷³⁵ 02:16, 6 September 2011 (UTC)

I like to know where these 42 of 'leading cosmologists and other quantum field theorists' are hiding. They weren't at the 50 years Everett (perhaps only David Deutsch). Why are they in the closet? Are they so afraid to be called crackpot, though in the leading field they are in the majority according this poll. Do they come together in dark places? And why David Deutsch says in ted, and here in other words, that only ten percent maybe fewer, talk about parallel universes? http://193.189.74.53/~qubitor/people/david/structure/Documents/By%20Other%20People/PhilosophyNow.html Do the 10 percent consist of the leading ones? Being brilliant together but not in public? And why does David Raub call himself a political scientist, while this is the only poll you could possibly find of him? Can the authorities of the page answer this? — Preceding unsigned comment added by Willempramschot (talk • contribs) 14:05, 25 September 2011 (UTC) And if your answer is that the site just says 'cite' this poll, you're still given unnecessary credibility to this poll — Preceding unsigned comment added by Willempramschot (talk • contribs) 14:20, 25 September 2011 (UTC)

Because Raub's poll is already very widely cited, a mention on Wikipedia isn't likely to boost its prominence. Rather than exclude it, it should be refuted/contradicted, ideally by Deutsch. Even if it were utterly fabricated, the poll needs to be mentioned, because of the attention it has received. --Wragge (talk) 15:04, 25 September 2011 (UTC)

Very widely cited by who? Other than Frank Tippler, and What the Bleep? Both are extremely controversial. The only others are a bunch of internet-surfers, who take it to be true at first sight. And why should David Deutsch be ideally for a good refutation? He is not even mentioned in this poll. If someone claims there are Red Blue Purple Elephants, he has to prove that they are there, the only thing I have to do is show that it's very implausible, exactly what I did in my previous post with the poll of David Raub. At least you can mention that this poll is controversial. And this poll is refuted by Victor J Stenger in the unconscious quantum (I don't have a copy, so I can't quote it) — Preceding unsigned comment added by Willempramschot (talk • contribs) 17:32, 25 September 2011 (UTC)

I'm sorry but Tegmark is really a freaking ridiculous figure. I quote: Although the poll was highly informal and unscientific (several people voted more than once, many abstained, etc), it nonetheless indicated a rather striking shift in opinion compared to the old days when the Copenhagen interpretation reigned supreme. Perhaps most striking of all is that the Many Worlds interpretation (MWI), pro- posed by Everett in 1957 [1–3] but virtually unnoticed for about a decade [4,5], has survived 25 years of fierce crit- icism and occasional ridicule to become the number one challenger to the leading orthodoxy, ahead of the Bohm [6], Consistent Histories [7] and GRW [8] interpretations. Why has this happened? The purpose of the present pa- per is to briefly summarize the appeal of the MWI in the light of recent experimental and theoretical progress, and why much of the traditional criticism of it is being brushed aside. I summarize: Altough this is a completely unscientific poll, with people who did a workshop (wow that's impressive) voting freaking twice of which the staggering number of 8! people voted for many-worlds, I can conclude that many-worlds is worldwide the main contestant of Copenhagen. I'm sorry but this guy should become prime minister of propaganda. Elsewhere he says popper isn't right because scientists mostly do justifying of theories, in stead of falsifying. Well perhaps this view is where it went, and got you in all this dishonest psychosis babbling. Bah! And the guy is freaking immoral for publishing articles about quantum suicide. Bah bah bah. — Preceding unsigned comment added by Willempramschot (talk • contribs) 12:20, 28 September 2011 (UTC)

Quantum suicide is definitely a triple bah score. But did you notice the references and the following paper? Surely it wasn't to briefly summarize an admittedly poor anecdote. Still, around here, three out of four peg a marksman fair and square.—Machine Elf ¹⁷³⁵ 21:54, 28 September 2011 (UTC)

--Willempramschot (talk) 13:44, 19 October 2011 (UTC) I'm sorry to be posting this message three times now but I meant to post it here all along, but that went wrong so you can delete the other one (the one you haven't deleted yet) (sorry for keeping you busy).

the problem with this page is that it's

1 not objective, 2 suggests that it is, by showing some criticism by people who are not really high regarded and then with comments make the arguments seem , and not really meant to be taken seriously, or relevant .

• The only thing that makes it a little better is that david raubs poll finely is a little bit questioned.

- When a poll with 22 people shows that the people asked clearly disfavor the poll, then it states less then 40 (like that is THE limit for a good poll, I don't say that it isn't but let the people decide, please). I conducted a poll that cleary contradicts the polls that do favor mwi (I now you cannot post any reasearch by yourself, so I will leave that up to others. 3' Misleading in other ways: Mwi has a lot of definitions, and physicists don't always use the same term. This site only choses to explain the really 'literal' one (which would be my chose too, when you chose to describe only one) but then seems to suggests that everyone seems to use this term.

'Poll I conducted

I now I can't post research of my own on the 'article' page, so I will leave that up to others. (If you want more information about the poll you can post below this post.

It's a little small, but even with this small number of (I assure you randomly picked, all theoretical/and or astronomers/cosmologists. It clearly contradicts the image of the representation of the reception on this page.

This poll is fully honest. I think I interpreted correctly but you are free to interpret it yourself.

The people who participated in this poll: David spergel, Carlo Rovelli, David polizer, David Finkelstein, Richard Muller, M.J. Rees, George F Smoot the Third, Goldreich, James Daniel Bjorken, Richter Burton, John Preskill, Leon N. Cooper, Robert Wald, James Binney, Yakir Aharanov, Andy Fabian, Ulrich Becker, Jim Al-Khalili, Frank Close, Frank Wilczek, Rodolfo Gambini, Jorge Pullin, John Baez. Donald Lynden-Bell, Rafael D. Sorkin, Mark Sredniki, Warren Siegel

This is the mail I sent to all the participants of the poll, with the results . I assure you it's fully honest (the thick part are the results):

Highly regarded gentlemen, you are all part of the happy few who answered my question a: I subscribe to the MWI that contains many parallel universes that differentiate during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits earth) b: I subscribe to the MWI that contains many parallel universes that split during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits earth constantly being created) c: I don't subscribe to a or b, because I think they are both *(probably) false d: I don't prefer any of the above FIRST SOME REMARKS -2 said c/d, those where counted c 1/2, d1/2, -one said I can't do anything with the poll, cause this has no empirical evidence and therefore has nothing to do with physics, to avoid all accusations of being biased I didn't count him, -one said c with a minor change, I don't subscribe to a or b, to once again avoid all acusations of being biased I didn't count him in, -one said I don't like both descriptions a or b, to me mwi just means unitary evolution but I chose b, to avoid all accusations of being biased I did count him as b, tough this answer really annoyed me. If for you this is just a equation to solve and you don't worry about the consequenses fine. But I now for a fact some people (besides) me do think it's relevant and are disturbed by the notion that they might split every second or there are an infinite number of people. Sorry I now that it's not usual for a poll conducter to give criticism to it's participants, but I needed this to get of my chest. -one said a,but with a very weak meaning of parallel meanings 'existing', once again to avoid being depicted as biased I counted him as a - one didn't say c, but send me a video of him in which the explanation most suited c in my opinion. Though he is inspired by Hugh Everett's interpretation. - one said he thought the multiverse was true, but couldn't subscribe to the copies of universes and inhibiters of earth. He voted a. I decided to didn't count him as a, because his answer was to different from the option he said he subscribed to - one said c, but said he was open-minded -one didn't see a difference in a or b, but chose b because he thought the word 'split' was better (I now have added that in b you multiply as do universes, and c you already exist in many universes, but I think the description itself wasn't incredibly vague) - one said d, He does however subscribe to the Everett relative state interpretation, and does think that all possible universes exist in 'some sense'. He also gave criticism for making MWI sound stupid. Well if that's the case I think you think the MWI questioned in this poll is stupid. He refered to (no explicit) research about asking a question and how the way you do it greatly influenced the poll. Well I can't respond to 'research' that I didn't read, I can respond to good commen sense: maybe some tiny percent of the (c's) or (d's) where subscribing to any mwi with parallel universes that wasn't mentioned in the poll, But I think it's very unlikely (since I think the logical thing would be to make notice of that) It is important that to some of you c included *(probably) and some of you didn't. I did this because I feared people would be more inclined to vote d, even if they really disliked a or b, because they couldn't say c, because of the philosophical notion that you couldn't say an unubservable chimp with high heals is ruling the universe is false, because you cannot test it. This may have had some effect on the poll. Though before I did this (after I think approximatelly more than 15 answers, but I'm not really sure) , c also was most voted by far.

The results C: 18 D: 7 A: 1 b: 2

if you want to use this poll for things like wikipedia or other sources you're free to do that, I will vouch for the statement that this poll is fully honest, and I also vouch for the statement david raubs poll most likely isn't. I conducted the poll under the name 'Gertjan Kouweheuve' because I didn't wanted that any of my posts elsewhere would influence the poll. That's the only lie I permitted myself to, with this poll.

Thank you all very much for participating, including the ones I gave some harsh criticism Best regards, Edo Blaauw P.s I also had an answer of Leon N. Cooper, but I can't find his email-adress somehow, so if someone how knows him could send this to him that would be nice. P.p.s for your enjoyment: extra comments X1: I think the many worlds interpretation is nonsence. It does not survive Occham's Razor. !me! when asked what his response was to mwi-ers answer <Occam's razor actually is a constraint on the complexity of physical theory, not on the number of universes. MWI is a simpler theory since it has fewer postulates> he said (I don't understand it, but I think some will) !me! X1: Any theory that predicts enormous numbers of copies of the universe none of which are directly observable is introducing a huge redundancy for explaining one small effect. That to me is quite wrong and disobeys Occham's razor. It is easier to imagine that our concept of a particle or a quantum are wrong in some way. There are already hints of this from such matters as the spectra of diatomic molecules which are radically affected by whether the nuclei are identical or not. If as in Oxygen the nuclei are the same and of spin zero then every other line in the rotational spectrum of the molecule is missing! How does the molecule know its tiny nuclei are identical? X2 Sure, my answer is definitely "c". I do not think that MW is good or useful, in any variant. X3 The many-worlds theory is a silly mistake, mistaking possibilities for actualities. It comes from the attempt to deny the statistical meaning of psi vectors and regard them as real things, present in the individual system; and nevertheless to avoid the mistaken theory of "collapse" that such reification originally led to. The theory that people actually use has one world, no collapse, transition probabilities, and incomplete descriptions. X4 NO TO MWI X5 My best answer is c. The theory is false because it is inconsistent. X-CD1 a c/d vote said he considered it a argumentum absurdum, that we lack knowledge and he would have voted c if it not contained the phrase 'both false' XD one d said: If a parallel universe is unobservable even in principle, then it's meaningless, according to established scientific method. "Meaningless" means it's neither true nor false, since it's untestable

— Preceding unsigned comment added by Willempramschot (talk • contribs) 08:26, 19 October 2011 (UTC) Though of course you could bring the argument that Martin Gardner is highly regarded, but I mean not in physics. And Peres perhaps is in someway, and Roger Penrose surely is, but the sneaky quotes hat 'sneaky' makes the arguments seem not that strong, or relevant still remains. —--Willempramschot (talk) 13:44, 19 October 2011 (UTC)

Appearances to the contrary, please don't post such material on the ‘Talk’ page either, see WP:TALK, WP:NOT#OR, WP:SELFCITE and WP:RS. Thanks—Machine Elf ¹⁷³⁵ 22:51, 19 October 2011 (UTC)

Can This Article Be Improved?

The "Reception" section discussion shows that the existing article is un-representative of the actual reception of MWI within the scientific community. This points out a larger problem, which is that all the rest of the article needs to be re-written to be consistent with the (soon to be updated) Reception section, which documents the fact that the intelligibility of MWI is disputed by most scientists and scholars who have considered it. Someone reading the existing article would get the impression that MWI is actually a viable and meaningful interpretation of quantum mechanics. There are certainly scientists who believe this (at least for their own personal vision of MWI, no two of which are mutually compatible), but there are many more who do not. I think the existing article tried to accommodate this (to some extent) by being careful to qualify all the claims of MWI enthuiasts with the word "claim", etc., and ideally each of these claims that are disputed by the majority of reputable scientists would be accompanied by an explanation (or reference to an explanation) of why most reputable scientists believe the claim is false (for example, the claim that decoherence resolves all interpretational issues).

My point is that not only does the Reception section need to to revised to accurately reflect the reception of MWI, but all the rest of the article needs to be revised to accurately represent the views of those whose "reception" is documented in the Reception section. This will inevitably lead to an article that appears less enthusiastic and less unequivocally favorable to MWI. However, I believe it will be more in keeping with Wikipedia editorial policy. Hopefully the MWI enthuiasists editing this article will understand that these changes are proposed only in the spirit of trying to make the article conform more closely to Wikipedia policy. I think we all understand that our own personal enthusiasms are not necessarily shared by the mainstream scientific community. This doesn't mean our views are wrong, but it isn't appropriate for us to try to use Wikipedia as a platform to propagandize or promote our own personal enthusiasms.AIMW32 (talk) 17:19, 17 October 2011 (UTC)

Will you be updating all the other interpretative QM articles also? See also my earlier response when you raised this issue. -- cheers, Michael C. Price ^talk 17:23, 17 October 2011 (UTC)

Your earlier comments missed the point. When I said the existing article is preposterously biased, you answered "I do not call having informative responses to criticisms 'preposterously biased'." Look, MWI makes certain claims, and these claims are criticized in the reputable literature, so we include those criticisms in the article, but then you add your "informative response to the criticisms", and then terminate the dialectic at that point. This convey the impression that MWI made claims, some people criticized those claims, those criticisms were exposed as fallacious, and hence MWI emerges triumphant. The end. But this is backwards from the actual state of affairs as it appears in the available reputable sources, which dispute the "informative responses". This is classic "novel narrative" of the kind that is expressly forbidden by Wikipedia editorial policy. I realize that you are merely trying to have the article convey what you regard as the truth, but what you regard as the truth is not what the great majority of reputable sources regard as the truth, and Wiki policy says the latter prevails.

Your earlier response went on to say "if in the interests of "balance" you wish to include quotations from the six books that 'are are decidedly NOT favorable toward MWI, and some of them are outright derisive', go ahead." Yes indeed, that's the plan, except that it isn't just "six books", it is the preponderance of the scholarly literature on this subject. However many it takes to make that point, that's how many will be cited.

You concluded your earlier remarks by saying "it is true that many "experts" are derisive - and the fact of their derision is worth reporting - although whether they still form a majority is not so clear." But the whole point of the Reception discussion was to show that the reputable literature makes it very clear that the derisive experts are still very much in the majority. My personal impression (not for inclusion in the article, obviously) is that enthusiasm for MWI - always a distinct minority - has been dwindling for many years, and that even the few remaining prominent proponents of MWI all have very different, and mutually exclusive conceptions of it - and none of them has ever succeeded in articulating their own conception in an intelligible way... but that's just me talking. I'm just trying to get you to see that your triumphalism is far removed from the verifiable material from reputable sources that is supposed to be the basis of this article.AIMW32 (talk) 18:48, 17 October 2011 (UTC)

Will you be updating all the other interpretative QM articles also? Michael C. Price ^talk 17:23, 17 October 2011 (UTC)

I advocate updating any articles that presently don't conform to Wikipedia editorial policy, and that present flagrantly biased views of their subject, at odds with the preponderance of the reputable literature on the subject.AIMW32 (talk) 18:48, 17 October 2011 (UTC)

WP:SPA/WP:NPOV/WP:SOAP/WP:IDHT… But “the dialectic” did not terminate at that point. You went on and on, ad nauseum, much as you're doing now, and you accomplished nothing apart from threatening the cat. Your WP:NPOV problem has been discussed at length, and you have refused to compromise in any way whatsoever. You're merely picking up exactly were you left off, so I've made this a subsection. Please review that discussion and reconsider the suggestion that “Maybe you should think about integrating smaller, fully-cited edits, into the existing material”. As I've already brought WP:SOAP to your attention, I've left a warning on your talk page. This is not a venue for you to voice your derision of “proponents” (now so-called “enthusiasts”) of MWI. WP:AGF, and try blogging.—Machine Elf ¹⁷³⁵ 23:05, 17 October 2011 (UTC)

AIMW32, if no MWIist has ever presented the theory in an "intelligible way" that presumably includes this article, in which case your help in improving it desirable. More likely, though, it is just a case that the adherents of one interpretation tend to find other interpretations incomprehensible. However your claim that the number of adherents is dwindling is not my experience, although your claim that every adherent has a different conception of MWI is undoubtedly true to some extent - the same situation exists with the Copenhagen interpretation, for which a myriad of sub-interpretations exists. As for being in the minority, well that is probably true of every interpretation. -- cheers, Michael C. Price ^talk 00:03, 18 October 2011 (UTC)

I think the article can be improved by explaining the Deutsch type thought experiments where measurements are undone and wavefuctions are uncollapsed in detail. As the article is written now, a reader can get the impression that operationally, the theory is the same as any other interpretation of QM. Only Quantum Suicide is mentioned explicitely, but the validity of that argument has been disputed. It's better to mention the Deutsch-type thought experiment in detail, as that argument only depends on unitary time evolution. Count Iblis (talk) 03:15, 18 October 2011 (UTC)

Yes, and probably enough content for its own article, probably. -- cheers, Michael C. Price ^talk 06:13, 18 October 2011 (UTC)

One further point about the Deutsch experiment - Everett wouldn't object "vociferously" to it, as AIMW72 claims, since Everett's original formulation allowed for interference effects between worlds (different elements of the universal wavefunction) to be restored (i.e. worlds merging) in principle, while acknowledging that this would be very hard in practice. -- cheers, Michael C. Price ^talk 08:00, 20 October 2011 (UTC)

I'm sorry to be posting this message twice, but I think it's better suited here (so you can of course delete it from 'the criticism and misconceptions' section: the problem with this page is that it's 1 not objective, 2 suggests that it is, by showing some criticism by people who are not really high regarden and then with that 'sneaky' makes the arguments seem not that strong, and not really meant to be taken seriously. The only thing that makes it a little better is that david raubs poll finely is a little bit questioned. 3 mwi has a lot of definitions, and physicists don't always use the same term. This site only choses to explain the really 'hard' one (which would be my chose to) but then seems to suggests that everyone seems to use this term. When a poll with 22 people clearly disfavoring the poll, then it states less then 40 (like that is THE limit for a good poll, I don't say that it isn't but let the people decide, please).

I conducted a poll that cleary contradicts the polls that do favor mwi (I now you cannot post any reasearch by yourself, so I will leave that up to others. It's a little small, but even with this small number of (I assure you randomly picked, all theoretical/and or astronomers/cosmologists (I think the last term isn't used very often) it clearly contradicts the image of the representation is being presented by yourself. I don't think it's really awful to be a 'little' biased yourself, but I do think you should at least admit that.

This poll is fully honest, I think I interpreted correctly but you of course can do your own interpretation. The people who participated in this poll: David spergel, Carlo Rovelli, David polizer, David Finkelstein, Richard Muller, M.J. Rees, George F Smoot the Third, Goldreich, James Daniel Bjorken, Richter Burton, John Preskill, Leon N. Cooper, Robert Wald, James Binney, Yakir Aharanov, Andy Fabian, Ulrich Becker, Jim Al-Khalili, Frank Close, Frank Wilczek, Rodolfo Gambini, Jorge Pullin, John Baez. Donald Lynden-Bell, Rafael D. Sorkin, Mark Sredniki, Warren Siegel

This is the mail I sent to all the participants of the poll, with the results.

— Preceding unsigned comment added by 213.10.212.48 (talk) 08:22, 19 October 2011 (UTC)

I assure you it's fully honest:

Highly regarded gentlemen, you are all part of the happy few who answered my question a: I subscribe to the MWI that contains many parallel universes that differentiate during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits earth) b: I subscribe to the MWI that contains many parallel universes that split during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits earth constantly being created) c: I don't subscribe to a or b, because I think they are both *(probably) false d: I don't prefer any of the above FIRST SOME REMARKS -2 said c/d, those where counted c 1/2, d1/2, -one said I can't do anything with the poll, cause this has no empirical evidence and therefore has nothing to do with physics, to avoid all accusations of being biased I didn't count him, -one said c with a minor change, I don't subscribe to a or b, to once again avoid all acusations of being biased I didn't count him in, -one said I don't like both descriptions a or b, to me mwi just means unitary evolution but I chose b, to avoid all accusations of being biased I did count him as b, tough this answer really annoyed me. If for you this is just a equation to solve and you don't worry about the consequenses fine. But I now for a fact some people (besides) me do think it's relevant and are disturbed by the notion that they might split every second or there are an infinite number of people. Sorry I now that it's not usual for a poll conducter to give criticism to it's participants, but I needed this to get of my chest. -one said a,but with a very weak meaning of parallel meanings 'existing', once again to avoid being depicted as biased I counted him as a - one didn't say c, but send me a video of him in which the explanation most suited c in my opinion. Though he is inspired by Hugh Everett's interpretation. - one said he thought the multiverse was true, but couldn't subscribe to the copies of universes and inhibiters of earth. He voted a. I decided to didn't count him as a, because his answer was to different from the option he said he subscribed to - one said c, but said he was open-minded -one didn't see a difference in a or b, but chose b because he thought the word 'split' was better (I now have added that in b you multiply as do universes, and c you already exist in many universes, but I think the description itself wasn't incredibly vague) - one said d, He does however subscribe to the Everett relative state interpretation, and does think that all possible universes exist in 'some sense'. He also gave criticism for making MWI sound stupid. Well if that's the case I think you think the MWI questioned in this poll is stupid. He refered to (no explicit) research about asking a question and how the way you do it greatly influenced the poll. Well I can't respond to 'research' that I didn't read, I can respond to good commen sense: maybe some tiny percent of the (c's) or (d's) where subscribing to any mwi with parallel universes that wasn't mentioned in the poll, But I think it's very unlikely (since I think the logical thing would be to make notice of that) It is important that to some of you c included *(probably) and some of you didn't. I did this because I feared people would be more inclined to vote d, even if they really disliked a or b, because they couldn't say c, because of the philosophical notion that you couldn't say an unubservable chimp with high heals is ruling the universe is false, because you cannot test it. This may have had some effect on the poll. Though before I did this (after I think approximatelly more than 15 answers, but I'm not really sure) , c also was most voted by far. The results

C: 18 D: 7 A: 1 b: 2

if you want to use this poll for things like wikipedia or other sources you're free to do that, I will vouch for the statement that this poll is fully honest, and I also vouch for the statement david raubs poll most likely isn't. I conducted the poll under the name 'Gertjan Kouweheuve' because I didn't wanted that any of my posts elsewhere would influence the poll. That's the only lie I permitted myself to, with this poll.

Thank you all very much for participating, including the ones I gave some harsh criticism

Best regards, Edo Blaauw P.s I also had an answer of Leon N. Cooper, but I can't find his email-adress somehow, so if someone how knows him could send this to him that would be nice. P.p.s for your enjoyment: extra comments X1: I think the many worlds interpretation is nonsence. It does not survive Occham's Razor. !me! when asked what his response was to mwi-ers answer <Occam's razor actually is a constraint on the complexity of physical theory, not on the number of universes. MWI is a simpler theory since it has fewer postulates> he said (I don't understand it, but I think some will) !me! X1: Any theory that predicts enormous numbers of copies of the universe none of which are directly observable is introducing a huge redundancy for explaining one small effect. That to me is quite wrong and disobeys Occham's razor. It is easier to imagine that our concept of a particle or a quantum are wrong in some way. There are already hints of this from such matters as the spectra of diatomic molecules which are radically affected by whether the nuclei are identical or not. If as in Oxygen the nuclei are the same and of spin zero then every other line in the rotational spectrum of the molecule is missing! How does the molecule know its tiny nuclei are identical? X2 Sure, my answer is definitely "c". I do not think that MW is good or useful, in any variant. X3 The many-worlds theory is a silly mistake, mistaking possibilities for actualities. It comes from the attempt to deny the statistical meaning of psi vectors and regard them as real things, present in the individual system; and nevertheless to avoid the mistaken theory of "collapse" that such reification originally led to. The theory that people actually use has one world, no collapse, transition probabilities, and incomplete descriptions. X4 NO TO MWI X5 My best answer is c. The theory is false because it is inconsistent.

X-CD1 a c/d vote said he considered it a argumentum absurdum, that we lack knowledge and he would have voted c if it not contained the phrase 'both false'

XD one d said: If a parallel universe is unobservable even in principle, then it's meaningless, according to established scientific method. "Meaningless" means it's neither true nor false, since it's untestable

— Preceding unsigned comment added by Willempramschot (talk • contribs) 08:26, 19 October 2011 (UTC)

Though of course you could bring the argument that Martin Gardner is highly regarded, but I mean not in physics. And Peres perhaps is in someway, and Roger Penrose surely is, but the sneaky quotes hat 'sneaky' makes the arguments seem not that strong, or relevant still remains. — Preceding unsigned comment added by Willempramschot (talk • contribs) 11:59, 19 October 2011 (UTC)

--Willempramschot (talk) 13:56, 19 October 2011 (UTC)

<big>Poll

I'm sorry this where the options, it got a little hard to read.

a: I subscribe to the MW I that contains many parallel universes that differentiate during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits earth)

b: I subscribe to the MWI that contains many parallel universes that split during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits earth constantly being created)

c: I don't subscribe to a or b, because I think they are both *(probably) false

and this where the results:

C: 18

D: 7

B: 2

A: 1