/
Article

Is the Moon There When Nobody Looks? Reality and the Quantum Theory

APR 01, 1985
Einstein maintained that quantum metaphysics entails spooky actions at a distance; experiments have now shown that what bothered Einstein is not a debatable point but the observed behavior of the real world.
N. David Mermin

In May 1935, Albert Einstein, Boris Podolsky and Nathan Rosen published an argument that quantum mechanics fails to provide a complete description of physical reality. Today, 50 years later, the EPR paper and the theoretical and experimental work it inspired remain remarkable for the vivid illustration they provide of one of the most bizarre aspects of the world revealed to us by the quantum theory.

This article is only available in PDF format

References

  1. 1. Daniel Greenberger, discussion remarks at the Symposium on Fundamental Questions in Quantum Mechanics, SUNY, Albany, April 1984.

  2. 2. A. Einstein, B. Podolsky, N. Rosen, Phys. Rev. 47, 777 (1935).https://doi.org/PHRVAO

  3. 3. Quoted by M. Jammer, The Philosophy of Quantum Mechanics, Wiley, New York (1974) p. 151.

  4. 4. A. Pais, Rev. Mod. Phys. 51, 863 (1979).https://doi.org/RMPHAT

  5. 5. The Born‐Einstein Letters, with comments by M. Born, Walker, New York (1971).

  6. 6. J. S. Bell, Physics 1, 195 (1964).

  7. 7. D. Bohm, Quantum Theory, Prentice‐Hall, Englewood Cliffs, N.J. (1951) pp. 614–619.

  8. 8. A. Aspect, P. Grangier, G. Roger, Phys. Rev. Lett. 47, 460 (1981). https://doi.org/PRLTAO
    A. Aspect, P. Grangier, G. Roger, Phys. Rev. Lett. 49, 91 (1982). https://doi.org/PRLTAO
    A. Aspect, J. Dalibard, G. Roger, Phys. Rev. Lett. 49, 1804 (1982).https://doi.org/PRLTAO

  9. 9. For a discussion of the views of today’s physicists toward the meaning of the quantum theory, see the interesting and provocative essay “Cognitive Repression in Contemporary Physics” by E. F. Keller, Am. J. Phys. 47, 718 (1977).https://doi.org/AJPIAS

  10. 10. L. Rosenfeld in Niels Bohr, His Life and Work as Seen by His Friends and Colleagues, S. Rozental, ed., North Holland, Amsterdam (1967) pp. 114–36.

  11. 11. G. Zukav, The Dancing Wu‐Li Masters—An Overview of the New Physics, Morrow, New York (1979) p. 282. On the same page it is also said that “Bell’s theorem is a mathematical construct which as such is indecipherable to the non‐mathematician,” a view that I hope the rest of this article will dispel.

  12. 12. H. Stapp, Nuovo Cimento 40B, 191 (1977).

  13. 13. A. Pais, “Subtle is the Lord…” The Science and the Life of Albert Einstein, Oxford U.P., New York (1982) p. 456.

  14. 14. N. Bohr, Phys. Rev. 48, 696 (1935).https://doi.org/PHRVAO

  15. 15. What follows is a somewhat refined version of an argument I published a few years ago in Am. J. Phys. 49, 940 (1981), incorporating some improvements suggested by Richard Friedberg. https://doi.org/AJPIAS
    For other elementary treatments see J. S. Bell’s, beautiful essay, “Bertlemann’s Socks and the Nature of Reality,” J. Phys. (Paris) 42, C2‐41 (1981), https://doi.org/JOPQAG
    B. d’Espagnat’s article in the November 1979 Scientific American, or d’Espagnat’s recent book, In Search of Reality, Springer‐Verlag, New York (1983).

  16. 16. For a survey of other attempts to realize the EPR experiment, and the variants of Bell’s original argument used to interpret experimental tests, see J. F. Clauser, A. Shimony, Repts. Prog. Phys. 41, 1881 (1978).https://doi.org/RPPHAG

  17. 17. R. P. Feynman, Int. J. Theor. Phys. 21, 471 (1982).https://doi.org/IJTPBM

More about the authors

N. David Mermin, Cornell University.

In These Collections
Related content
/
Article
Since 2008, more than 100 colleges and universities in the US have stopped offering an undergraduate physics major. What happened?
/
Article
The thermodynamic and quantum mechanical properties of topological insulators provide a path toward scalable energy storage in information-based batteries.
/
Article
At the end of the turbulent 1960s, the postwar funding boom in US physics came to a crashing halt. The lessons learned then may be helpful to today’s physicists.
/
Article
Interviews with 22 successful early-career physical scientists and engineers reveal that networking has been one of the most critical ways to nurture their careers.
This Content Appeared In
pt-cover_1985_04.jpeg

Volume 38, Number 4

Get PT newsletters in your inbox

pt_newsletter_card_blue.png
PT The Week in Physics

A collection of PT's content from the previous week delivered every Monday.

pt_newsletter_card_darkblue.png
PT New Issue Alert

Be notified about the new issue with links to highlights and the full TOC.

pt_newsletter_card_pink.png
PT Webinars & White Papers

The latest webinars, white papers and other informational resources.

By signing up you agree to allow AIP to send you email newsletters. You further agree to our privacy policy and terms of service.