The von Neumann–Wigner interpretation says that consciousness causes collapse. Sometimes it is just called von Neumann interpretation. I don't believe that von Neumann ever said anything in that direction. There is a passage in his book Mathematical Foundations of Quantum Mechanics where he describes the Heisenberg cut and the arbitrariness of its exact position in great detail, but makes it quite clear that the cut has to remain in the physical world. Wigner indeed published a philosophical article (Remarks on the Mind-Body Question) where he argued that consciousness is the thing about whose existence we can be sure (following Descartes' cogito ergo sum), that if the body influences the mind, it is only natural to assume that the mind also influences the body, and where he introduced his friend doing the observation and argued that assuming his fiends mind to be in a superposition of having observed incompatible outcomes would be unfriendly. It was written (and argued) in the typical style of a philosophical article. In later years, Wigner changed his mind and rejected the interpretation he proposed earlier.

Claims that quantum mechanics (or the Copenhagen interpretation) would say that consciousness causes collapse feel troubling to me. I wondered before why some pop-sci accounts of quantum mechanics claim this. But then I read that same claim in Steven Weinberg's article The Trouble with Quantum Mechanics, this time clearly attributed to Eugene Wigner. Luboš Motl wrote both about Weinberg's article and the questionable interpretation, used those occasions to say some true and enlightening things about quantum mechanics1, but pretended that they just used confusing words:

Consciousness is just a "spiritually sounding" synonym of the ability of an observer to be aware of a measured value of an observable.

These views were associated with Wigner and von Neumann and their usage of the word "consciousness" made their comments provocative and famous in the broader scientific public.

Does this interpretation really deserves the honour to be associated with the names of von Neumann and Wigner? Why and how did it happen historically that this interpretation was named after them? (Wigner's article even refers to an article by Fritz London and Edmond Bauer from 1939 as source for the proposed interpretation.) Is my belief correct that von Neumann never wrote or said anything resembling that interpretation?

1For example: "Weinberg correctly says that "objective probabilities" are untenable. Yes, probabilities at a particular situation must always refer to the state of mind of someone who knows something – and it depends whom we pick. Probabilities at a given moment are always observer-dependent or subjective."


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I now checked all references (and external links) from the wikipedia article (except the few behind pay walls), and none of them used that unjustified name. The closest was a single use of von Neumann-Wigner quantum theory and multiple uses of von Neumann quantum theory in the article of H. Stapp from 2001

The name von Neumann interpretation was apparently created on 10 January 2010 on wikipedia by the mistake of a single contributor which didn't write anything else on wikipedia. The name Wigner was added on 21 February 2010 in an apparent attempt to fix the previous mistake. Hence this interpretation doesn't deserve the honour of the names of von Neumann and Wigner, one reason being that this honour wasn't even granted intentionally.

  • $\begingroup$ Maybe a side note but: Do you also suggest that something should be done about the wikipedia page? $\endgroup$ Commented Feb 14, 2017 at 9:55
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    $\begingroup$ @MikaelFremling I corrected the wikipedia page with the original mistake now. Maybe I will later also try to correct some of the other places to where the mistake has propagated like Luboš Motl's blog, or Quora, assuming my changes are just accepted silently. $\endgroup$ Commented Feb 14, 2017 at 22:42
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    $\begingroup$ I just know of the term today, but it has a separate Wikipedia page now: Von Neumann–Wigner interpretation $\endgroup$
    – Ooker
    Commented May 29, 2018 at 6:38

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