Quantum probability and many worlds

Meir Hemmo, Itamar Pitowsky

Research output: Contribution to journalArticlepeer-review


We discuss the meaning of probabilities in the many worlds interpretation of quantum mechanics. We start by presenting very briefly the many worlds theory, how the problem of probability arises, and some unsuccessful attempts to solve it in the past. Then we criticize a recent attempt by Deutsch to derive the quantum mechanical probabilities from the non-probabilistic parts of quantum mechanics and classical decision theory. We further argue that the Born probability does not make sense even as an additional probability rule in the many worlds theory. Our conclusion is that the many worlds theory fails to account for the probabilistic statements of standard (collapse) quantum mechanics.

Original languageEnglish
Pages (from-to)333-350
Number of pages18
JournalStudies in History and Philosophy of Science Part B - Studies in History and Philosophy of Modern Physics
Issue number2
StatePublished - Jun 2007

Bibliographical note

Funding Information:
We thank the Israel Science Foundation (Grants Numbers 879/02 and 240/06) for supporting this research.


  • Many worlds
  • Quantum probability
  • Rational decision theory

ASJC Scopus subject areas

  • History
  • General Physics and Astronomy
  • History and Philosophy of Science


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