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Misinterpretation of the Bohrian view
I believe that this article incorrectly attributes a positivist slant to Bohrs interpretation. Although this is indeed the view taken by his student Heisenberg, and is often taken as being representative of the copenhagen interpretation, it is not true of Bohrs ideas (regardless of whether they make it into the definition of the cophenhagen interpretation). I myself still struggle to come to terms with Bohrs relationist notions of measurement and reality, but I am certain that it is unfortunately not as simple as a positivism.
Also with regards to whether interpretations of QM is a subject for physics or metaphysics, it is as much physics as Einsteins deriving of the lorentz transformations (ie. special relativity). Both attempt to clarify and extend an existing operationally adequete although conceptually incomplete theory by questioning what relation the theory has to reality.
Nic.
Made a few corrections
Mainly POV things.
I removed the phrase
"Einstein's Relativity demonstrates that "instantaneous" has meaning only for observers sharing a single reference frame. No universal time reference exists so the "instantaneous wave function collapse" of the Copenhagen Interpretation is left undefined."
since it builds on the misunderstanding that the wave function collapse should be understood as a physical process (it should not). The "instantaneous wave function collapse" is not really a problem in quantum field theory or relativistic quantum mechanics, and in the various "delayed choice" experiments as well as in Einstein and Rosens article on the subject from 1931 we see that the shift involved in the observation/reduction of the wave function is so fundamental it actually stretches backwards in time.
edit summary for undoing of an edit that linked to Occasionalism
For this undo, the edit summary reads "No, it is not part of the Copenhagen interpretation that all events are taken to be caused directly by the divine."
For obvious reasons I am not simply undoing that undo, but I am here saying that it was not good enough that it was not accompanied by a proper talk page explanation. Moreover, I am saying that it is reasonably defensible or well-arguable that it was a wrong undo.
Albert Einstein is well known to have said and thought that the Copenhagen interpretation was a religion. Moreover, the article to which the undone edit linked, Occasionalism, has as the second sentence of its lead, "(A related theory, which has been called "occasional causation", also denies a link of efficient causation between mundane events, but may differ as to the identity of the true cause that replaces them.<Steven Nadler, 'The Occasionalism of Louis de la Forge', in Nadler (ed.), Causation in Early Modern Philosophy (University Park, PA: Pennsylvania State University Press, 1993), 57–73; Nadler, 'Descartes and Occasional Causation', British Journal for the History of Philosophy, 2 (1994) 35–54.>)"
There are plenty of reliable sources that more or less agree with Einstein and that parenthesis. The link was a see also. It it reasonable to allege that the Copenhagen interpretation is a religious or philosophical doctrine. It is not proper Misplaced Pages neutrality to censor out that allegation. It may be appropriate to present argument against the allegation, but simple censorship is contrary to Misplaced Pages policy. One may agree with a vast number of physicists, in the opinion that Einstein after 1927 was a doddery old fool, but as a Misplaced Pages editor one must accept that it is no more than a notable opinion or point of view. Rosenfeld says that Einstein's name on the EPR paper made it "a bolt from the blue" to Bohr. Bohr is said to have had a horseshoe by the front door of his country house, and when challenged that he shouldn't believe in such things, to have replied that he didn't believe in them, but that the horseshoe worked even if one didn't believe in it.
I think the undone see also link should be restored.Chjoaygame (talk) 01:23, 21 January 2015 (UTC)
- An entertaining but nonsensical argument when applied to a hard science page in an encyclopedia. Why not cite Lao Tze or Confucius, both of whom made comments which could conceivably be construed as connected to particle physics? The difficulty, Chjoaygame, is as comedian Steven Wright said: "You can't have everything. Where would you put it?" If every Misplaced Pages editor's personal philosophical hobbyhorse has to be linked to every Quantum Physics page, it dilutes the value of the factual content in favor of random babbling. JacquesDelaguerre (talk) 06:37, 21 January 2015 (UTC)
- You have not offered an argument that calls for a reply.Chjoaygame (talk) 07:18, 21 January 2015 (UTC)
- You have offered a fanciful explanation for why a page about superstition should be linked from a hard science page. No argument is needed. Feel free to edit philosophy and religion pages, but please don't "improve" the science pages with nonsensical material. JacquesDelaguerre (talk) 15:59, 21 January 2015 (UTC)
- You have not offered an argument that calls for a reply.Chjoaygame (talk) 07:18, 21 January 2015 (UTC)
- It takes quite a stretch of the imagination to find the relevance in the linked page. I see there is a mention of an author who describes a similarity between occasionalism and the Copenhagen interpretation, though the parallel there is between a god and an observer, so the metaphor seems confused. If one allowed speculative links like this, as JacquesDelaguerre implies, the 'see also' section would be longer than the article. Besides, the main thrust of occasionalism appears to be to ascribe a godlike will behind the course of events, which appears to be directly contrary to the Copenhagen interpretation. The Copenhagen interpretation says absolutely nothing about the causation of any particular observation being selected, only about probabilities. I agree with the removal of the link. —Quondum 17:25, 21 January 2015 (UTC)
physical interpretation
A new edit writes "The Copenhagen interpretation is a loosely-knit informal collection of axioms or doctrines that attempt to express in quotidian language the mathematical formalism of quantum mechanics."
I think that the Copenhagenist interpretations are not so much aimed at producing quotidian language, as they are aimed at matching the mathematical formalism with physical meaning.
- I don't know two quantum physicists prominent in the field who agree on the physical meaning! :) JacquesDelaguerre (talk) 21:28, 12 February 2015 (UTC)
- I guess you are right about that.Chjoaygame (talk) 01:58, 13 February 2015 (UTC)
It is true that, for this purpose, Copenhagenism demands the use of ordinary language; for example Bohr writes "Here, it must above all be recognized that, however far quantum effects transcend the scope of classical physical analysis, the account of the experimental arrangement and the record of experimental observations must always be expressed in common language supplemented with the terminology of classical physics."
- Bohr, N. (1948). On the notions of complementarity and complementarity, Dialectica 2: 312–319.
The language, however, is just the vehicle for the interpretive task, which is to express the physical meaning of the mathematical formalism. For example, non-commutativity of operators is a simple mathematical fact. The interpretative question is what does that mathematical fact mean in physical terms? The call for supplementation by the terminology of classical physics signals a call for physical interpretation, beyond only quotidian language. In ordinary language, non-commutativity means that 'multiplication' depends on the sequential order of the 'factors'. This is not yet a physical meaning. The non-commutativity has the physical meaning that no laboratory apparatus can bring about physical coexistence of the respective physical states represented by the non-commutative operators.Chjoaygame (talk) 13:35, 12 February 2015 (UTC)
Key is that the account of the apparatus not use quantum theoretical ideas or language. It's a specific kind of arcane language that is to be avoided, namely quantum mechanical language. This is well explained by Günter Ludwig. I would like to emphasize the positive duty of interpretation: to tell how to build apparatus that embodies given items of the mathematical formalism, and how to find the mathematical formalism to describe given apparatus. The fellows in the workshop making the apparatus know nothing of quantum mechanics, and should positively avoid learning its concepts, as a matter of principle. They speak ordinary language laced with classical physical ideas.Chjoaygame (talk) 18:08, 12 February 2015 (UTC)
- I do not disagree with much of what you have said, merely asserting that the revised text is a little better than what stood there before. Along the lines of the CI itself, let's strive to keep the article reasonably intelligible to the layman ... so if you can improve the intro without making it longer, go ahead! JacquesDelaguerre (talk) 21:26, 12 February 2015 (UTC)
- You are right that we should strive to keep the article reasonably intelligible to the layman. All three, Bohr, Heisenberg, and Born, explicitly said that the quantum postulate has big philosophical implications, perhaps more or less unrecognised by professional philosophers.Chjoaygame (talk) 02:31, 13 February 2015 (UTC)
fact not perception
A new edit writes "The fundamental axiom of the Copenhagen interpretation is the "postulate of the quantum", that subatomic events are only perceptible as indeterministic physically discontinuous transitions between discrete stationary states."
I think that Copenhagenism intends much more than how things are perceived. I think Copenhagenism refers to how things happen. For example, Bohr writes of "the discontinuous exchange of energy between atoms required by the quantum postulate." Born writes "Every process consists of elementary processes, which we are accustomed to call transitions or jumps". Born and Heisenberg report "a (spontaneous) change of state consists, also in the continuous spectrum, in a “jump” of the system from a point W′ to another W′′ ".
- Bohr, N. (1928). The quantum postulate and the recent development of atomic theory, Nature 121:580–590.
- Born, M. (1927). Physical aspects of quantum mechanics, Nature 119: 354–357.
- Born, M., Heisenberg, W. (1927/1928). La mécanique des quanta, pp. 143–181 of Électrons et Photons: Rapports et Discussions du Cinquième Conseil de Physique, tenu à Bruxelles du 24 au 29 Octobre 1927, sous les Auspices de l'Institut International de Physique Solvay, Gauthier-Villars, Paris, p. 152.
I think these people are talking about fact, not perception.Chjoaygame (talk) 15:15, 12 February 2015 (UTC)
- Interesting point. I was trying specifically in that edit to avoid the mistake of confusing our perception (through our instruments and measurements) of the "quantum universe" with any existential reality, which is it seems, precisely what Bohr was saying when he suggested to Einstein that "we may have reached the limits of the usefulness of visualization". QM doesn't tell us what's happening, what it looks like, what it smells like "down there" in Subatomia :) It gives us a schematic mathematical tool for a limited description, which doesn't begin to meet up with anything tangible to the human organism until about the point of angular bonds in chemistry. So I used the word "perception" which, to judge from your comment, may be too loaded a term for this article. I will not be offended if you improve my prose which, I firmly believe, was an improvement on the previous somewhat tangled introduction which I found yesterday on this page. Thank you for your comment! JacquesDelaguerre (talk) 17:02, 12 February 2015 (UTC)
- Thinking a little more about this. Copenhagenism recognizes three elements in a report of an atomic phenomenon. (1) the atomic object itself. This is mostly imperceptible to naked sensation, and is even an inference rather than an ordinary macroscopic physical object. That doesn't make it unreal or unfactual or entirely imperceptible or merely a subjective interpretation. It is perfectly real, though perhaps not too easy to describe, or even may be unvisualisable. (2) the apparatus that prepares and detects the atomic object. This is an arrangement of ordinary perceptible, enduring, and real physical objects. (3) the many members of the laboratory team who read and re-read and check and discuss and agree about the instrumental record of the phenomenon. There can be agreement about the results because they are easily perceptible, because of the design of the apparatus. No subjectivity remains here if the laboratory team is working well. I think Wigner missed this point. It is true that there is room for interpretive difference about where there boundary is drawn between (1) and (2), but that is neither mysterious nor essentially subjective: one can report on it in a perfectly objective way.Chjoaygame (talk) 19:45, 20 February 2015 (UTC)
- Léon Rosenfeld writes
- "... It is essential to realize that any observation involves a sharp separation of the nondescript flow of events into two parts: the observer and the observed system. It is by performing—or rather imagining—this cut, that the observer takes up a “detached” position which enables him to speak of the observed system “objectively”, i.e. in the same way as any other observer taking his place. Cuts of this kind can be made in many ways—one may look at the same thing from many points of view—but the concepts framed to state the results of the observations are related to the standpoint of the observer in such a way that it is always possible to pass from any one standpoint to any other, full objectivity is thereby ensured. In physics, where we confine ourselves to the aspects of experience from which all manifestation of life is excluded, the only part of the “observer” that enters into the picture is itself a physical system, an apparatus which records signals or permanent marks left in it by the observed system, and which any real observer (or sufficiently complex “brain”) can examine and “read” at leisure whenever he wishes."
- Rosenfeld, L. (1967), pp. 122–123.
- Rosenfeld, L. (1967). Niels Bohr in the thirties: consolidation and extension of the conception of complementarity, pp. 114–136 of Rosental, S. (1967).
- Rosental, S. editor (1967). Niels Bohr. His life and work as seen by his friends and colleagues, North-Holland, Amsterdam.Chjoaygame (talk) 08:37, 21 February 2015 (UTC)
Typo or unusual language
"10.In the present state of physical knowledge, the intestinal workings of atomic and subatomic processes are not open to visualization in ordinary space-time or causal pictures.". Intestinal is probably an autocorrect, but not being knowledgeable in the field, I just wanted to make sure that word isn't one of those imaginative uses of language that physicists are given to. David Brooks (talk) 17:50, 20 February 2015 (UTC)
- The word 'intestinal' here is neither a typo nor an autocorrect. It is an echo of the use of the word by Antoine Lavoisier and Pierre-Simon Laplace in their classic Mémoire sur la chaleur (Mémoires de l'Académie des sciences (1780), pp. 355–408) on their caloric theory, used also more recently with the same meaning by Clifford Truesdell. The reason for the use here is rhetorical, to bring the reader to pause and reflect on the essential inaccessibility to direct observation of the mechanisms of atomic and subatomic processes. True, it has a colourful or slightly eccentric or obsolete or as you say imaginative feeling about it, and is not the most routine language. Perhaps there is some reason why Misplaced Pages should avoid such scientific literary allusion or such oddity. If you feel so, I will not object to replacing it by some less colourful word such as for example 'inner'.Chjoaygame (talk) 19:17, 20 February 2015 (UTC)
language
The lead currently starts with this sentence: "The Copenhagen interpretation is a loosely-knit informal collection of axioms or doctrines that attempt to express in everyday language the mathematical formalism of quantum mechanics."
The problem here is not whether to use the words 'quotidian' or 'everyday'. The problem here is that the sentence is not focused on what needs to be said. The interpretation is an expression of a match between mathematical formalism and physical meaning. The concept of physical meaning is not explicitly mentioned in the sentence. It is nearly trivially true that the expression is to be in ordinary language supplemented with the concepts of classical physics. But the attempt is at expressing a match between mathematical formalism and physical meaning, not at putting mathematics into ordinary language.Chjoaygame (talk) 15:45, 22 February 2015 (UTC)
Heisenberg writes about the early days when the Copenhagen spirit was being developed:
"... But I noticed that mathematical clarity had in itself no virtue for Bohr. He feared that the formal mathematical structure would obscure the physical core of the problem, and in any case, he was convinced that a complete physical explanation should absolutely precede the mathematical formulation."
- Heisenberg, W. (1967), p. 98.
- Heisenberg, W. (1967). Quantum theory and its interpretation, pp. 94–108 in Rozental, S. (1967).
- Rosental, S. editor (1967). Niels Bohr. His life and work as seen by his friends and colleagues, North-Holland, Amsterdam.Chjoaygame (talk) 17:03, 22 February 2015 (UTC)
"the intestine workings of atomic and subatomic processes"?
I'm curious about the use of the word "intestine" here. My edit was reverted (with the edit comment: reverted to classical physical terminology, this is not purple prose; see Lavoisier and Laplace, Truesdell). Since these names are not mentioned in the article, and my Googling seems to turn up only biology-related books, could I have a pointer to an example of this use in a physics text? —Quondum 00:08, 10 March 2015 (UTC)
- I have above on this page cited the use of the word by Lavoisier and Laplace in their classic work on their caloric theory. Also I have pointed to its use by a respected recent author, Clifford Truesdell. Right here I don't have hard copies of those sources, which I previously borrowed from the library. But now I Google it at your request. I find as follows.
- I find I was problably working from the original French. I find also on the internet an English translation that uses the more colourless English word 'internal', so in English I have only the example of Truesdell, who is a fine writer of English and a reliable source on thermodynamics. He uses the word seven times in his The Tragicomical History of Thermodynamics 1822–1854, Springer, New York, ISBN 0387904034. The word is an ordinary word of the English language (see OED), and Misplaced Pages uses ordinary language. I don't think Misplaced Pages has a rule that one must use the most colourless word, as long as one represents the meaning of the source accurately. So I think it reasonable to use the word 'intestine' here for the present purpose.Chjoaygame (talk) 01:34, 10 March 2015 (UTC)
the word 'locality'
With reference to this present article, the word 'locality' is currently under discussion at Talk:Interpretations of quantum mechanics#Non-locality in Copenhagen Interpretation. A few notes about it might be useful here, since the present article is perhaps not quite explicit on that word. I think the word in the present context is largely an invention of later scholars, not part of the original Copenhagen language. Thus it may be problematical to discuss whether Copenhagenism is "localist" or not.Chjoaygame (talk) 00:43, 10 March 2015 (UTC)Chjoaygame (talk) 01:41, 10 March 2015 (UTC)
Bell 1964
The Introduction reads
- "THE paradox of Einstein, Podolsky and Rosen was advanced as an argument that quantum mechanics could not be a complete theory but should be supplemented by additional variables. These additional variables were to restore to the theory causality and locality . In this note that idea will be formulated mathematically and shown to be incompatible with the statistical predictions of quantum mechanics. It is the requirement of locality, or more precisely that the result of a measurement on one system be unaffected by operations on a distant system with which it has interacted in the past, that creates the essential difficulty."<Bell, J.S. (1964). On the Einstein Podolsky Rosen paradox, Physics 1: 195–200.>Chjoaygame (talk) 00:43, 10 March 2015 (UTC)
Wigner 1976
In lectures quoted by <Wheeler, J.A., Zurek, W.H., eds. (1983), Quantum theory and measurement, Princeton U. Press, 1983>, Eugene Wigner says
- "The preceding argument shows that any theory of hidden variables conforming with the postulate of locality is in conflict with quantum mechanics."<p. 294 of Wigner, E.P. (1976/1983). Interpretation of quantum mechanics, pp. 260–314 in Wheeler, J.A., Zurek, W.H., eds. (1983).>Chjoaygame (talk) 00:43, 10 March 2015 (UTC)
Howard 2007
Howard writes
- "In brief, separability asserts the existence of independent real states of affairs in spatially separated regions, and locality asserts that the real state of affairs in one region of space cannot be affected super-luminally by events in another region. Locality is entailed not only by relativistic locality constraints but also by the requirement that theories be testable, for were locality not to obtain then there would be no principled way to distinguish the falsity of theory’s prediction about the outcome of a measurement from the effects of stray extraneous influences from afar. Separability is defended as a well-nigh necessary, a priori condition for the possibility of the objective individuation of physical systems (more on this below)."<Howard, D. (2007). Revisiting the Einstein–Bohr dialogue, The Jerusalem Philosophical Quarterly 56: 57–90.>Chjoaygame (talk) 00:43, 10 March 2015 (UTC)
Weihs et al. 1998
These authors write in their introduction
- "The assumption of locality in the derivation of Bell’s theorem requires that the individual measurement processes of the two observers are spacelike separated."<Weihs, G., Jennewein, T., Simon, C., Weinfurter, H., Zeilinger, A. (1998). Violation of Bell’s inequality under strict Einstein locality conditions, Phys. Rev. Lett. 81(23): 5039–5043.>Chjoaygame (talk) 00:43, 10 March 2015 (UTC)
De Muynck 1986
De Muynck writes
- "From the following, however, it should be clear that the mere existence of hidden variables is sufficient to yield the Bell inequalities. Hence not only local but also nonlocal hidden variables theories are incompatible with quantum mechanics. Local and nonlocal theories being on an equal footing it also follows that the Bell inequalities are completely irrelevant to the problem of (non)-locality in hidden variables theories."<De Muynck, W. (1986). The Bell inequalities and their irrelevance to the problem of locality in quantum mechanics, Phys. Lett. 114A: 65–67.>Chjoaygame (talk) 00:43, 10 March 2015 (UTC)
Tommasini 2002
Tommasini writes
- "In fact, any kind of “nonlocality” or instantaneous “distant influence” is unacceptable in a relativistic world: due to the relativity of the simultaneity, suitable observers would describe this influence (whatever it is) as an effect of the future on the past . Fortunately for science, there is a way to completely reconcile the quantum theory with locality, causality and special relativity. This solution is quite natural and is based merely on known physics."<Tommasini, D. (2002). Reality, measurement and locality in quantum field theory, J. High Energy Phys. 02(7): 039.>Chjoaygame (talk) 00:43, 10 March 2015 (UTC)
Bohr and Heisenberg
I did not find convincing evidence that either Bohr or Heisenberg habitually used the term 'locality' in the present sense. This looks to me like an argument that is is not useful to try to say whether Copenhagenism is or is not 'localist'.Chjoaygame (talk) 00:43, 10 March 2015 (UTC)
Comments
It is generally accepted that the quantum mechanical formalism uses a state description of which the domain is configuration space, not ordinary physical space-time. In this sense, one might propose that quantum mechanics is "non-local". On the other hand, 'non-locality' is sometimes interpreted or intended to mean 'in violation of the rule against spooky actions at a distance'. Some people then try to make out that quantum mechanics essentially entails spooky actions at a distance. Indeed there is a vast industry busy at this, with research money flowing. Others argue that the quantum mechanical formalism does not refer to or deny action at a distance, but simply does not explicitly trace space-time linkages, though the term 'locality' is not used. I think Bohr and Heisenberg were of this view. Whether you like to say they believed in locality is up to you, a matter of opinion, I would say. Misplaced Pages should avoid seeming to commit itself on the semantical question of whether or not Copenhagenism is "localist".Chjoaygame (talk) 00:43, 10 March 2015 (UTC)
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