Talk:Philosophical interpretation of classical physics/Archive 1

message: Lamarckian evolution, with inheritance of acquired character, is a common misunderstanding of Darwinian evolution, in the popular mind.
That the world evolves in a random way when we are not measuring it, though not such a simple or important mistake, is a similar misunderstanding, by even experts, of quantum mechanics.  The probabilities are a property of experimental physics and not of nature.  I wish I could make this as clear as Messiah did.
I suppose biologists must have spent a lot of time learning to help people avoid that error.
The way to avoid the random nature error is to speak correctly about the philosophy of science.David R. Ingham
According to the "shut up and calculate" doctrine, this doesn't matter because we can't calculate it anyway, but who knows, it might matter.
Suppose Stephen Hawking had been right about entropy decreasing at the end of the universe.  The fact that quantum mechanics is internally deterministic might help to explain how this could happen.
Another problem with thinking that way is that it keeps one from understanding where the probabilities really do come from.
David R. Ingham 23:45, 22 September 2005 (UTC)
thread_title:  Analogy to Lamarckian evolution 

message: you say '"Physics and the Real World" by Carlos Bustamante, Jan Liphardt, and Felix Ritort, July, 2005' but don't give a journal. a google search finds http://www.physicstoday.org/pt/vol-58/iss-7/contents.html , but the article author is George F. R. Ellis; Bustamante et al is the previous article. If so, please fix.
other ref by Herbert P. Broida , looks like you may have copied and pasted a reference with the "[1]", but it didn't get pasted. Needs the full ref. GangofOne 20:37, 19 September 2005 (UTC)
thread_title: references?

message: Ħ Sentence by sentence, here are things I understand to be problematical:
Any process of measurement involves the application of outside forces to the object being measured, as when photons are directed at something and the paths of the photons are subsequently noted.  
::Ħ That is a very strong claim, hence it is difficult to maintain. How about measuring the dimensions of an object that radiates light by exposing photographic paper near to it and using similar methodologies?
If photons, electrons, or other quantum-scale entities used in the measurment process are described quantum mechanically, then the measurement process results in a deterministic description, i.e., a description that contains no probability factors. 
::Ħ It would be very helpful to have an operational definition of how a quantum mechanical description of a photon, electron, etc. is to be prepared.
However, to get the information into a notebook or (non-quantum) computer, it must be brought to the human scale where maintaining phase coherence is impossible. 
::Ħ Several items of information might be meant by “the information”: (1) The thus far undefined quantum mechanically defined (described?) photons or whatever that are used to make the measurements, (2) The measurements made.  What does it mean to “bring them to the human scale”?  If that were not enough, the reader is given no indication of why maintaining phase coherence would be desirable and why it is impossible.
::Ħ Why would a quantum computer be a better choice? If the mention of a quantum computer is a little joke here, then it will generally only serve to puzzle the average well-informed reader.
Because the classical approximation does not conform to the uncertainty principle, it must make mention of information that the quantum system, which does conform, cannot supply. 
::Ħ This statement promises much but delivers little to the average well-informed reader who cannot guess what information must be mentioned in a description made in terms of classical physics, nor does it even suggest how the inability to discuss one kind of information forces the fabrication of a second kind of information.
 This non-physical information is generated randomly. 
::Ħ Surely this is not something done by the experimenter with some kind of random number generator. But you’ve been speaking in terms of human intervention between physical system and human-intelligible report with words such as “must make mention.”
 In addition, phase information in the quantum description cannot be represented classically, and is lost.  
::Ħ If there is “information” or data, how can it be “lost”? Surely you must be talking about some feature of any experimental apparatus that can be used, but the reader has been totally misled up to this point
One of Messiah's examples involves measuring the position of an electron with light. 
::Ħ Citation, please.
 If the light's wave function is not known and hence cannot be included in the system wave function, then the predictions of the electron's position can only be stated in terms of probabilities, because the light photons exchange amounts of momentum with the electron which would then be unknown. 
::Ħ What if the light’s wave function is known?  
::Ħ And when you say  “which would then be unknown,” you have a pronoun that has an ambiguous referent. Do you mean that the momentum of the electron would be unknown?
Ħ I could try to guess appropriate ways of resolving all of these problems, but I would rather have the author’s response. P0M 15:08, 22 September 2005 (UTC)
replies: text: Good luck (whatever that means in QM terms ;-).  When you get back, please do provide citations to Messiah's book. I am working with our library to get the book back from someone so I can check it out. Volume 2, which I got today, does not seem to have the parts to which you refer.  I could start going through a dozen or so books that I have on hand, but even if they disagreed with you that might not be as useful as my understanding exactly what and how Messiah has stated things.  By the way, did Francis Weston Sears ever write specifically on this subject? I cursed my way through Sears and Zemansky, but the problem was not with the original work by Sears but because Zemansky had systematically reduced every bit of wonderful clarity in the original to a puddle of goo.  So I would like to see how Sears handles it. Haven't found anything so far, however. P0M 04:36, 28 September 2005 (UTC)
thread_title:  On the measurement paragraph 

message: A recent addition to the section on measurement says:
Some of the early failures of classical physics were direct consequences of its failure to limit the degree of detail in nature.
Physics cannot limit nature.  P0M 17:38, 22 September 2005 (UTC)
thread_title:  Unintended consequence of unclarity 

message: The current introduction mentions the need for a new "philosophical interpretation" of classical physics, due to quantum physics, which is fairly clear.  
Later, however, the article mentions a "direct interpretation"... but does not say what this means, or even what is being interpreted here--are we still talking about interpretations of classical physics or have we slipped into something else?  Does "direct interpretation" mean probablistic interpretation of quantum physics?
I suppose this is confusing to me because I am used to hearing about different interpretations of quantum physics, not different interpretations of classical physics.  In my opinion, the article needs more precision when talking about interpretations, especially using when using new terms.  Perhaps you should also mention which interpretation of quantum physics you are using, or whether this new interpretation of classical physics would be needed regardless of your interpretation of quantum physics.  WhiteC 20:33, 28 September 2005 (UTC)
replies: text: Thanks for fixing the problem, and making the article in general easier to read.  I would say you could get rid of the 'too technical' flag now, but I don't know who put it there in the first place.  WhiteC 19:19, 7 October 2005 (UTC)
thread_title:  Clarification of 'interpretation' needed 

message: "Some of the early failures of classical physics were not dynamical at all ..."
:There is a link for "dynamical," but it does not clarify the problem for the general reader which is: what kind of problems or failures are "dynamical"? What does this word mean in this context? What would be a synonym for it? P0M 23:24, 23 September 2005 (UTC)
replies: text: Do you mean that Time_evolution is not the problem? or what? P0M 04:48, 28 September 2005 (UTC)

text: Please paraphrase the original statement then. P0M 20:25, 8 October 2005 (UTC)

text: I think this sentence is o.k. now. P0M 01:19, 18 October 2005 (UTC)
thread_title:  point by point (1)

message: I have been mining Albert Messiah's Quantum Mechanics for citations and quotations. I am extremely impressed with the lucidity of his writing and recommend his book to others who may be interested in helping with this article. 
By the way, the conceptual difficulties that lie behind the need for this article also come up very clearly in quantum entanglement discussions. The common stumbling point is our macro-world assumption of the inevitability of simple location. Twins may become identical, but tickling the one in Africa does not make the one in S. America laugh, and between diving board and pool neither one of them will fail to move in a continuous manner as a function of time.  If one individual disappeared from the starting block and "materialized" at the finish line a very short time later, one would quite naturally suspect twins. (Especially if his time was d/c for the mile ;-) P0M 18:26, 1 October 2005 (UTC)
thread_title:  Kudos for Albert Messiah 

message: Quantum mechanics was discovered by the instruments of classical physics, just a chemistry was discovered with the instruments of alchemy and the first chicken hatched from an egg laid by some other type of bird.David R. Ingham 23:39, 7 October 2005 (UTC)
thread_title:  " highly refined instruments of modern physics" 

message: Our use of notebooks and (non-quantum) computers depends on the classical approximation to the operation of these devices and to the information stored in them.
This statement seems to be intended to say that quantum computers could be used to obtain reliable predictions regarding quantum phenomena that could not be obtained by our current crop of computers. If a classical computer can accurately simulate a quantum computer, and the difference between classical and quantum computers is one of speed and scale of operations that can be performed, how would moving the problem to a quantum computer give a fundamentally different kind of result? P0M 01:24, 11 October 2005 (UTC)
thread_title:  Quantum computer? 

message: I still think that it is essential to provide readers with volume number and page number whenever Messiah is claimed as the authority for some statement.  P0M 01:34, 11 October 2005 (UTC)
replies: text: Page numbers will still help. If there should happen to be one version with 594 pages in volume 1 and you were to cite page 332/594 and quote a sentence or two it would be no great problem to find the material.  In the version I have, the section to which you just made mention turns out to begin on p. 139, and once I knew that I was actually looking for a section by that title it wasn't hard to find even though it is not exactly at the beginning of the book. P0M 08:02, 11 October 2005 (UTC)
thread_title:  Footnotes needed for Messiah's book 

message: No, I don't think  helps at all.  It is not a matter of experiment.  The point is that classical physics not only does not provide a framework for expressing interaction.  The very description of nature itself leads to contradictory or at least ridiculously unphysical predictions without even including any forces or other interactions.
:Is "It is not a matter of experiment" basically what you wanted to say? That it is essentially a matter of a conceptualization that fails so badly to fit the reality it was intended to describe that it produces only nonsense? 
I am thinking that this should drive home the point that one should not seriously think in such a way.
David R. Ingham 03:53, 11 October 2005 (UTC)
replies: text: What is the intended referent for "this"?  What is the intended referent for "such a way"? Sorry if I appear thick-headed, but I have found that assuming I can guess what somebody else intended to say is a fairly reliable way to get myself even more confused. P0M 08:41, 11 October 2005 (UTC)
thread_title:  Dynamics versus kinematics. 

message: The article currently says, "One of Messiah's examples involves measuring the position of an electron with light. If the light's wave function is not known and hence cannot be included in the system wave function, then the predictions of the electron's position can only be stated in terms of probabilities, because the light photons exchange amounts of momentum with the electron which would then be unknown."  Where does he say that? Thanks.  P0M 01:17, 13 October 2005 (UTC)
replies: text: You don't mean the discussion starting on p. 45 that discusses how the wavelength of light that would be useful in such an attempt would be in the x-ray range, and then discusses the difficulty of measurement purely in terms of how strong a perturbation would be produced on an electron by that radiation, do you? P0M 02:37, 13 October 2005 (UTC)
thread_title:  Request for citation 

message: I don't think "implies" is the right word.
David R. Ingham 03:15, 15 October 2005 (UTC)
replies: text: Fixed. P0M 01:03, 18 October 2005 (UTC)
thread_title:  http://en.wikipedia.org/w/index.php?title=Philosophical_interpretation_of_classical_physics&curid=2690589&diff=25388356&oldid=25323074 

message: The expression "brought to the human scale" needs an operational_definition.  P0M 06:52, 30 September 2005 (UTC)
replies: text: This statement, too, needs to be redone. As it stands it does not have any clear meaning. P0M 20:27, 8 October 2005 (UTC)

text: I understand what your intent is, however, I do not know what the statement means. If you know what it means then it should be possible to explain what it means to other people. As it stands it cannot guide understanding. It serves only to obfuscate the discussion. P0M 23:24, 19 October 2005 (UTC)
thread_title:  Point by point  (2) 

message: The article claims: "The Copenhagen interpretation holds back from declaring quantum mechanics primary and from downgrading classical physics to the status of an approximation that uses terms for which there are no true referents." (Emphasis is mine.)  What terms without true referents does it use? P0M 01:01, 18 October 2005 (UTC)
replies: text: No. If you are going to claim that there are terms (words) without true referents, then you have to be willing to say what those words are. What words that classical mechanics uses have no true referents? Mass, energy, momentum, position in space, position in time? Name a few, please. P0M 02:41, 20 October 2005 (UTC)
thread_title:  Point by point (4) 

message: This section is, of course, why I, perhaps optimistically, deleted the "too technical" symbol.  Probably, for most readers who make any sense of the article at all, this will be the understandable part.
Perhaps it might be more conventional to put the easiest part at the top, but I like getting to the point first and explaining it below, as is done now.
In this context, the statistical mechanics paragraph is a bit technical and not essential, but I like it because it makes the point that it was the classical description of nature itself that first failed, not just its incompatibility with the accurate dynamical forces.  This seems to me to drive home the theme of the article.
-- Ingham
:I know where I got the information that I put in this section and can easily add citations. As a matter of fact, most of what I added is so much a commonplace of the discussions on quantum mechanics that multiple citations could be provided. But we have to be willing to try to live up to the standards of someone like Greene who can write about these matters with perfect clarity, and we have to be able to give accurate citations. P0M 02:56, 20 October 2005 (UTC)
thread_title:  Explanation 

message: Not only is this page difficult to understand but it is original research as the essay does not provide verifiable sources for the claims that are made, etc. I think this article should be deleted, but I am willing to see if it can be improved to something that is both understandable and verifiable. Trödel|talk 00:44, 20 October 2005 (UTC)
replies: text: Thanks for the suggestion. I can easily supply citations for the garden variety stuff I have tucked in here and there. Do you have suggestions for citation style? I think there is a way to make regular footnote superscript numbers and have them pop the reader down to a section of notes at the bottom of the article. P0M 03:00, 20 October 2005 (UTC)

text: An article that "presents it in a way" that has an orientation other than the neutral point of view is by definition a work of original research. Encyclopedic articles should present the information available on a subject not provide a new orientation to the subject at hand. If Messiah is the only source then there should be an encyclopedic article on him where this is one of the items discussed. Trödel|talk 03:27, 20 October 2005 (UTC)

text: I am of the opinion that if something can not be explained well to an educated person (in my case an educated college graduate with a B.S. in Physics) then it needs more editing. However, I am not sure that this article would survive a AfD vote since it is too much like original research. Thus I am not willing to invest the time in trying to more clearly articulate the ideas for intelligent non-scientists unless it will survive a challenge to its verifiability (and generally one source is not enough to create an article on). Trödel|talk 03:27, 20 October 2005 (UTC)

text: When there is only one reputed source, and repeated requests for page numbers are met with claims that it "is all in there somewhere. Just worry about making it correct and clear," then there does not seem to be any way to go forward. P0M 16:39, 20 October 2005 (UTC)
thread_title:  Difficult to understand 

message: I looked up footnotes.  The one I just added seems good to me.
I hope Interpretation of quantum mechanics will adopt the same style.
Or are there other suggestions?David R. Ingham 18:09, 20 October 2005 (UTC)
thread_title:  Footnote style 

message: There is not yet a clear division, here, between the quantum and classical descriptions of the measurement process.
The classical description must have been studied closely, in the dawn of quantum physics, to argue the uncertainty principle, but is less interesting now.
The quantum description may be an active subject of research, because of its complexity and its relevance to entanglement and to quantum computing.David R. Ingham 05:55, 21 October 2005 (UTC)
thread_title:  The measurement process 

message: Suppose we rename Interpretation of quantum mechanics to History of the interpretation of quantum mechanics, rename this article to "Subtleties of the relation between quantum an classical descriptions of nature]], and archive this entire article and re-write it, closer to its text book sources but without plagiarizing?
There is good historical material in that other article, but its title, as it is, is misleadingly outdated.  Its category would change from physics to history of physics.
Part of the objective for the new article should be to help understand entanglement, if possible.
Text book authors work hard to make it believable to people who did not grow up understanding quantum mechanics, and maybe there is much more of that quality that can be taken without adhering too closely.  This would allow this article to be checked sentence by sentence against its sources, as people here want, but would still be representative of a modern view.
David R. Ingham 10:50, 26 October 2005 (UTC)
replies: text: As I mention on the Wikipedia:Articles for deletion/Philosophical interpretation of classical physics page, this article is mis-named, as it fails to mention any topic that is normally discussed when the "philosophy of classical mechanics" is discussed. This article seems to be enitrely about quantum.  I would think the the Stanford encyclopedia of philosophy might provide a good example of what this article should look like. linas 15:17, 26 October 2005 (UTC)

text: For example  and  and  and  for a 'mainstream' view of classical physics philosophy.linas 15:25, 26 October 2005 (UTC)
thread_title:  Toward agreement on a neutral point of view 

message: There were problems with the old introduction, but this one fails to identify the central point that the classical description includes more information than can be observed.David R. Ingham
Trying to fix that, I see that we have deviated from the issue.  Sorry if I don't always have time or express myself clearly enough to keep things on track.
The subject is not just the verbal representation of classical physics, it is that the mathematical form itself contains untestable information.  This is the point that is philosophical in nature.  (Quantum mechanics does not suffer from this problem, in this case.)  The uncertainty principle is a failure of classical physics and not of quantum physics.  (Perhaps my previous sentence is all that is needed for than introduction.)  As Feynman puts it, the fact that the information is not testable does not in itself condemn classical physics to the status of an approximation, what does is that its predictions are wrong.  The statistical mechanics examples show that some of these failures follow directly from the classical description itself.
* page 2-9 of The Feynman Lectures on Physics, Vol. III
* Albert Messiah, Quantum Mechanics, English translation by G. M. Temmer of Mécanique Quantique, 1966, John Wiley and Sons, p. 45
David R. Ingham 21:23, 30 October 2005 (UTC)
replies: text: The section on the measurement process is in need of help too. Please see the discussion page for the rfd where I have listed problems. P0M 04:45, 31 October 2005 (UTC)
thread_title:  Introduction 

message: I looked this up :"Physics and the Real World" by George F. R. Ellis, Physics Today, July, 2005 I don't see what the error you refer to is. Maybe you could write one of your essays and post it to your personal website , or to wikinfo.org where original research is ALLOWED (along with an unmangled version of this Phil Interp. of Cl Phys. page while you're at it.) GangofOne 03:14, 3 November 2005 (UTC)
thread_title:  Physics and the Real World (is that a tv show?) 

message: The current text says:
The Copenhagen interpretation was formulated while quantum mechanics was new and no one was used to it, so it describes quantum mechanics in terms of classical physics in a way that is adequate for practical purposes. The Copenhagen interpretation holds back from declaring quantum mechanics primary and from downgrading classical physics to the status of an approximation that uses terms for which there are no true referents at the micro scale. That is, it still spoke as though the uncertainty principle were a part the the quantum theory itself rather than part of nature.
After reviewing Heisenberg's Physics and Philosophy, among other early works, I believe the above statement does not correctly reflect the facts. Note that no citations have been provided. The passage consists of groundless assertions made in support of one point of view. P0M 08:10, 3 November 2005 (UTC)
thread_title:  Point by point (6) 

message: Failing to find any place in Messiah's book that actually fits the statement that "One of Messiah's examples involves measuring the position of an electron with light. If the light's wave function is not known and hence cannot be included in the system wave function, then the predictions of the electron's position can only be stated in terms of probabilities, because the light photons exchange amounts of momentum with the electron which would then be unknown," I have decided to track through the literature in more-or-less historical sequence to discover where there might be an actual assertion that is at least close to what has been claimed in the article. 
*The Revolution in Physics, Louis de Broglie.  Nothing even close.
*Atomic Physics and Human Knowledge, Niels Bohr. Chapter on "Discussion with Einstein on Epistemological Problems in Atomic Physics." This article is very well written, but difficult to comprehend unless one has thoroughly learned the exact definitions of many terms. It does not appear to support David's specific contentions, however.
*The Nature of the Chemical Bond, Linus Pauling, pp. 10-11:
The stationary quantum states of a molecule or other system are states that are characterized by definite values of the total energy of the system. These states are designated by a quantum number, represented by the number n, say, or by a set of two or more quantum numbers, each of which can assume any one of certain integral values. The system in the nth stationary quantum state has the definite energy value W[n] and is represented by the wave function ψ[n]. Predictions can be made about the behavior of the system known to be in the nth quantum state by use of the wave function. These predictions, which relate to the expected results of experiments to be carried out on the system, are in general not unique, but instead statistical in nature. For example, it is not possible to made a definite prediction of the position of the electron relative to the nucleus of a normal hydrogen atom; instead, a corresponding probability distribution function can be found.
:The bold print is mine. --P0M
:I believe that the above quotation is illustrative of a more general characteristic of the problems involved in locating an electron or other quantum domain entity by causing a second quantum domain entity to impinge upon it, and, subsequently, determining the location at impact of the second object on a detection screen. Neither the electron nor the photon has a location or a trajectory in the sense of the words as used in macro-scale discourse. Each has its ψ function. When the photon and the electron interact with each other, their ψ functions are both changed in some way. The energy of the light can be known because we can arrange an experimental apparatus that reliably emits light of a certain frequency.  The direction of the line between the light source and the target can only be determined (when there is no intervening electron or other light blocker) by observing its point of arrival on the target.  So if it hits the electron we can only be approximately aware of its "line of flight" because we do not know where the electron is except in a general way. Then the electron will strike the detection screen at some point at some verifiable point. That means that we have only two points out of three defined clearly. The "orbit" (to once again use figurative language from the macro world) of the electron will be changed by the impact of the photon. That is to say, its ψ function will be changed. So the ψ function of the electron, which originally had to have been unknown, has now been changed by the impact of the photon, which originally had an unknown ψ function. The resultant ψ function now has two unknown components. If we haven't hit it too hard with the photon, then we know what its orbital is, so we know what its frequency and energy are, but we do not know its position. Its position was precisely what we were trying to determine in the first place, and it seems that the one thing we can know for sure is that we have jarred it to someplace it wouldn't be if we had left it alone. I'm doing this in first-draft mode, thinking at the keyboard. Please correct what I have written if needed. P0M
Failure to give a citation may necessitate removing the statement quoted above. Emended,P0M 00:28, 17 October 2005 (UTC)
replies: text: I cannot help make it correct and clear unless you will tell me the source in Messiah or somebody who writes equally clearly like Francis Sears. I have scanned the two volumes of this text and looked in the obvious places. I have looked through the index. I have searched the other physics texts that I have on hand. Nowhere do I find a trace of the kind of discussion you mention. P0M 02:46, 20 October 2005 (UTC)

text: One note: the statement above: "Neither the electron nor the photon has a location or a trajectory in the sense of the words as used in macro-scale discourse. Each has its ψ function. When the photon and the electron interact with each other, their ψ functions are both changed in some way." is not the way QM works. To understand how two particles interact, one generally must construct a single wave function that describes both. There are special situations where one can simplify things. For example in solving the hydrogen atom, one normally ignores interactions with the proton and just calculates a single electron moving in the proton's static coulomb field. In general, however, you can't do that. For two entangled photons you need a wave function that includes both. The case of an electron and a photon gets even messier because photons can be created and destroyed in the process. --agr 10:56, 6 November 2005 (UTC)
replies: text: Thank you very, very much. At last some light on this subject. P0M 16:22, 6 November 2005 (UTC)
thread_title:  Point by point (3) 

message: Per Wikipedia:Articles_for_deletion/Philosophical_interpretation_of_classical_physics. Most were for delete, but could not agree on what form of deletion. --Woohookitty(cat scratches) 11:42, 5 November 2005 (UTC)
replies: text: So what now?Karol 09:05, 28 November 2005 (UTC)
replies: text: We need to decide what the article is intended to explain, and then we need to find a title that is clear.P0M 15:06, 28 November 2005 (UTC)
thread_title: Afd failed

message: I have not had new sources to add recently, but here is a very good one.
Physics Today, April 2006, "Weinberg replies", p. 16,  "... but the apparatus that we use to measure these variables—and we ourselves—are described by a wave function that evolves deterministically.  So there is a missing element in quantum mechanics:  a demonstration that the deterministic evolution of the wave function of the apparatus and observer leads to the usual probabilistic rules."
In principle the answer is given by the correspondence principle, but the details are very complicated, so there is not a clear derivation of "the usual probabilistic rules".  Theorists tend to be more often quoted than experimentalist and less involved with this issue.
David R. Ingham 05:57, 10 May 2006 (UTC)
thread_title:  New material 

message: To avoid repeating the same text again, I am putting a link to my comment about Schrödinger's cat:  [].
This is another example of how it is dangerous to think of our classical picture as real.  It is only an approximation to QM, and the rules about when it is valid can be subtle.  David R. Ingham 20:49, 23 August 2006 (UTC)
thread_title:  Entangled cat