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Quantum Foundations

Quantum Foundations is an approach to the problem of interpretation of quantum mechanics, trying to formulate a theory that provides a suitable (if not the correct or missing) foundation for the theory itself.

DiVincenzo and Fuchs[1] wrote a paper with this title in honor of pioneering papers published in Rev. Mod. Phys. on the topics of quantum foundations and interpretations, which indeed is almost spooky on its own! Besides the tribute to the journal, that makes for an informative brief review of the literature. This did not please Ballentine[2] whose own RMP contribution on that topic[3] had been overlooked (they apologized for the omission but did not reply on the attacks on their formalism):

Unfortunately, DiVincenzo and Fuchs continue to mystify measurement in QM, as if it were some deep philosophical concept that must be treated before QM has even been fully formulated [...] And they give too much attention to two marginal interpretations: the many-worlds interpretation (MWI) and quantum Bayesianism (QBism) [...] The initial assumption of QBism is not valid.

Despite the clear offense taken, he also makes excellent points:

The usual role of an interpretation of QM is to begin with the established mathematical formalism and provide an intuitively comprehensible idea of the physical process that the math describes.

and also points to an interesting paper he wrote on various types of probabilities (his main attack being precisely on Fuchs' QBism).[4]


  1. Quantum foundations. D. P. DiVincenzo and C. A. Fuchs in Physics Today 72:50 (2019).
  2. Reviews of quantum foundations. D. Ballentine in Physics Today 73:11 (2020).
  3. The Statistical Interpretation of Quantum Mechanics. D. Ballentine in Rev. Mod. Phys. 42:358 (1970).
  4. Propensity, Probability and Quantum Theory. D. Ballentine in Found. Phys. 46:973 (2016).

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