Probability in Quantum Mechanics

Special Issue of Studies in History and Philosophy of Modern Physics

Volume 38, Issue 2

Guest Editors: Roman Frigg and Stephan Hartmann



The formalism of quantum mechanics provides us with the probabilities for certain events to occur – this much is uncontroversial. But how are we to understand these probabilities? The essays in this special issue approach this question from different angles. The first three contributions take as their point of departure the philosophy of probability and discuss what the two main outlooks – objective and subjective interpretations of probability – have to offer in the context of quantum mechanics. The following five papers explore the question of how probabilities in particular interpretations of quantum mechanics – modal interpretations, relative state interpretations, Bohmian mechanics, and GRW theory – can be interpreted. The last three essays address specific issues: non-standard probability and algebraic quantum field theory, quantum propensities, and the relation decoherence and the interpretation of probability.

We would like to thank the editors of Studies in History and Philosophy of Modern Physics, Dennis Dieks and Jos Uffink, for their sustained support of the project of putting together a special issue on the topic of  probabilities in quantum mechanics. Some of the papers here published were first presented at a conference on quantum probabilities that we organised at the London School of Economics in February 2004. We would like to thank the participants of the conference for their contributions to the discussions, as well as the British Society for the Philosophy of Science (BSPS) for financial and the Centre for Philosophy of Natural and Social Science (CPNSS) for logistical support. Last but not least, we would like to thank the anonymous referees for many careful and detailed reports, which were invaluable in the production of the contributions to this issue.



Jeff Bub: Quatnum Probabilities as Degrees of Belief.

Carlton Caves, Chris Fuchs and Rüdiger Schack: Subjective Probability and Quantum Certainty. 

Tim Maudlin: What Could Be Objective About Probabilities?

Dennis Dieks: Probability in Modal Interpretations of Quantum Mechanics.

David Wallace: Quantum Probability from Subjective Likelihood: Improving on Deutsch's Proof of the Probability Rule.

Meir Hemmo and Itamar Pitowsky: Quantum Probability and Many Worlds.

Craig Callender: The Emergence and Interpretation of Probability in Bohmian Mechanics.

Roman Frigg and Carl Hoefer: Probability in GRW Theory.

Miklós Rédei and Stephen J. Summers: Quantum Probability Theory.

Mauricio Suárez: Quantum Propensities.

Guido Bacciagaluppi: Probability, Arrow of Time, and Decoherence.