I am learning about EPR and local realism in physics. However, in that context, nobody talks about the philosophical implications and deeper meaning of local realism, objective reality, hidden variable, entanglement and the logic required to understand these phenomena.

I was wondering if you could provide some references for a few papers/books that cover these concepts from a philosophical point of view. I would like to know more about them. It would be appreciated to list a few references ranging from beginner to more advanced materials.

  • 1
    Tim Maudlin is self described as sticking close to the ancient Greek idea of physics (“nature”), and if that speaks to you I’d recommend him. He also self describes as making a living explaining EPR and John Bell. I’d recommend What Bell Did and that will help find other good papers.
    – J Kusin
    Jul 2, 2022 at 16:38
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    The Internet Encyclopedia of Philosophy has a good article on EPR and its relation to later ideas like Bell's theorem (note that the EPR paper doesn't show that QM is incompatible with local realism, it just argues that QM is incomplete and we need more variables to satisfy something the article terms the 'reality criterion'). For Bell's work I recommend the collection of his papers Speakable and Unspeakable in Quantum Mechanics, especially the paper "La Nouvelle Cuisine" which discusses locality in terms of light cones.
    – Hypnosifl
    Jul 2, 2022 at 22:40
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    Also see Bell's paper on the EPR paradox here. One other point is that advocates of the Everett interpretation sometimes argue that it actually restores locality by exploiting a a loophole in Bell's proof where he assumed that each pair of measurements yield a single definite pair of results as soon as both measurements are complete.
    – Hypnosifl
    Jul 2, 2022 at 22:43
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    @NikosM. Something like 10.1 of this: plato.stanford.edu/entries/qm-action-distance or like this post physicsforums.com/threads/… (I’m sure there’s more out there just what I could find easily).
    – J Kusin
    Jul 5, 2022 at 18:22
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    @JKusin - Maudlin believes there is an objective truth about which direction on a time-like worldline constitutes "past-to-future" but he says "a foliation is not required for there to be a lapse of time" (although he does think a preferred foliation may be needed for a coherent interpretation of quantum mechanics; as you mentioned he favors some kind of pilot-wave). See his discussion on p. 116-117 of philocosmology.rutgers.edu/images/uploads/TimDavidClass/…
    – Hypnosifl
    Jul 5, 2022 at 18:45

3 Answers 3

  1. Tim Maudlin's book Philosophy of Physics: Quantum Theory.

  2. Look at Gerard T'Hooft's (Nobel Prize Winner, 1999) posts and responses on Physics Stackexchange on the subject of determinism, as he is probably the most notable (living, RIP Weinberg) physicist who understands the philisophical implications of the quantum measurement problem. He has his own profile on there, which is just his name. Steven Weinberg also had some interesting philisophical papers about the measurement problem too.

  3. Primary Sources of the EPR paper, and the responses to it, Bell's original papers, and look into the phenomena of decoherence, in conjuction with Wocjeich Zurek's ideas of einselection and quantum darwinism.

  4. SEP page on the subject.


A good pointer to the EPR-problem is the Wikipedia entry. The article contains links to download

  • the original paper of Einstein, Podolsky and Rosen
  • the reply of Bohr in the same journal
  • a corresponding entry in Stanford Encyclopedia of Philosophy

You find even more references in the article, in particular to Bell's papers. I recommend also "Andrew Whitaker: Einstein, Bohr and the Quantum Dilemma. Cambridge (1996)", Ch. 6 and 7.

Added after reading the EPR-paper: The EPR-paper starts with two useful statements which link physics and natural philosophy:

  • Physical reality: „If, without in any way disturbing a system, we can predict with certainty […] the value of a physical quantity, then there exists an element of physical reality corresponding to this physical quantity.

  • Complete theory: „[…] the following requirement für a complete theory seems to be a necessary one: every element of the physical reality must have a counterpart in the physical theory.“

The problematic term from natural philosophy is the term „physical reality“.

The authors do not define the term, their second statement does not fix the kind of relation between the physical quantity from the theory and the corresponding element of physical reality.

Their first statement requires the existence of a map from a certain subset of physical quantities of the theory to the set of elements of physical reality.

While their second statement goes the other way round. It requires for a complete theory the existence of a map from the set of all elements of physical reality to a certain subset of physical quantities of the theory.

  • I do not quite get how this is not a definition of physical reality. Yes, of course there needs to be a mapping from the physical quantities to the elements of physical reality. This mapping is naturally evolving in the pragmatic context of experimentation, measurement, and theory as a standardized system of human practice "against" nature (or physical reality) - the Deweyan "Experience". Or am I wrong here? If so, a complete theory would mean nothing less than that we can accurately describe and predict every element of reality we have pragmatic experience with, even allowing for extension.
    – Philip Klöcking
    Jul 5, 2022 at 15:52
  • @ Philip Klöcking For an explanation see „Franco Selleri: Die Debatte um die Quantentheorie, Vieweg 1983.“ Referring to the EPR-paper Selleri states on p. 83 „Außerdem könnte das, was uns unmittelbar als räumliche Ausdehnung erscheint, aus Eigenschaften folgen, die sich von unserer Wahrnehmung unterscheiden und zu einer Empfindung führen, welche die wahren physikalischen Eigenschaften topologisch entstellt.“ 1/2
    – Jo Wehler
    Jul 5, 2022 at 17:15
  • @Philip Klöcking In my words: E.g., we know that the experience of impenetrability of a solid body is created by the electric forces between its atoms. The latter seems a better approximation to an element of physical reality then the mechanical property of impenetrability. 2/2
    – Jo Wehler
    Jul 5, 2022 at 17:15
  • Yes, but why does physical reality have to be eternal and fundamental? Why cannot it be just about however reality discloses itself to us, may it be in immediate sensual experience or mediated through instruments? Why does it have to be "wrong" that a thick titanium plate is impenetrable for most kinetic effects below significant relativistic speeds, just because our description of the fact changes? Of course, the definition is about modern physics but the core of what "reality" and "completeness" means in these citations seems to me inherently contextualised by possible (ie. past) experience.
    – Philip Klöcking
    Jul 5, 2022 at 18:16
  • @Philip Klöcking The description of impenetrability from your example does not seem „wrong“ to me. But it is the description of an observation, not the explanation of an observation. We approach elements of physical reality by explaining our observations on the basis of physical theories. - Possibly I did not get your point. Therefore: What about elaborating your comment to a separate question?
    – Jo Wehler
    Jul 6, 2022 at 3:58

David Bohm (1917–1992) followed the implications of EPR to its cosmic conculsion. e.g. books. Ervin László comes to mind too - review. All interesting but very speculative. The EPR that can be named is not the enduring and unchanging name.

Bohm's Gnosis: The Implicate Order

Bohm believes that the bizarre behavior of the subatomic particles might be caused by unobserved subquantum forces and particles. ... [He] believes that this "hiddeness" may be reflective of a deeper dimension of reality. He maintains that space and time might actually be derived from an even deeper level of objective reality.

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