What is Probability

  title={What is Probability},
  author={Simon Saunders},
Probabilities may be subjective or objective; we are concerned with both kinds of probability, and the relationship between them. The fundamental theory of objective probability is quantum mechanics: it is argued that neither Bohr's Copenhagen interpretation, nor the pilot-wave theory, nor stochastic state-reduction theories, give a satisfactory answer to the question of what objective probabilities are in quantum mechanics, or why they should satisfy the Born rule; nor do they give any reason… 
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Quantum mechanics under the Copenhagen interpretation is one of the most experimentally well verified formalisms. However, it is known that the interpretation makes explicit reference to external
Everett and evidence
Much of the evidence for quantum mechanics is statistical in nature. Relative frequency data summarizing the results of repeated experiments is compared to probabilities calculated from the theory;
Everettian Probabilities, The Deutsch-Wallace Theorem and the Principal Principle
  • H. Brown, G. Porath
  • Philosophy
    Jerusalem Studies in Philosophy and History of Science
  • 2020
This paper is concerned with the nature of probability in physics, and in quantum mechanics in particular. It starts with a brief discussion of the evolution of Itamar Pitowsky’s thinking about
Objective Probability in Everettian Quantum Mechanics
  • Alastair Wilson
  • Philosophy
    The British Journal for the Philosophy of Science
  • 2013
David Wallace has given a decision-theoretic argument for the Born Rule in the context of Everettian quantum mechanics (EQM). This approach promises to resolve some long-standing problems with
Branch-counting in the Everett interpretation of quantum mechanics
  • S. Saunders
  • Physics
    Proceedings of the Royal Society A
  • 2021
A defence is offered of a version of the branch-counting rule in the Everett interpretation (otherwise known as many worlds interpretation) of quantum mechanics that both depends on the state and is
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Some notes about quantum physics, an interpretation if one wishes, are put forward, insisting on ‘closely following the mathematics/formalism, the ‘nuts and bolts of what quantum physics says’.
The Everett Interpretation: Probability
The Everett interpretation of quantum mechanics is, inter alia, an interpretation of objective probability: an account of what probability really is. In this respect, it is unlike other realist
Constructor theory of probability
  • C. Marletto
  • Mathematics
    Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2016
It is proved that the unpredictability of measurement outcomes necessarily arises in superinformation theories, and sufficient conditions are established for a superinformation theory to inform decisions as if it were probabilistic, via a Deutsch–Wallace-type argument.
Many worlds: decoherent or incoherent?
The incoherence problems presented necessitate either the provision of a new, non-probabilistic empirical grounding for the notions of robustness and emergence in the context of decoherence, or the abandonment of the Deutsch–Wallace–Everett programme for quantum theory.
The Quantum Mechanical Frame of Reference
Everett demonstrates the appearance of collapse, within the context of the unitary linear dynamics. However, he does not state clearly how observers are to have determinate measurement records, hence


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The demonstrations of von Neumann and others, that quantum mechanics does not permit a hidden variable interpretation, are reconsidered. It is shown that their essential axioms are unreasonable. It
Theory of Games and Economic Behavior.
This is the classic work upon which modern-day game theory is based. What began more than sixty years ago as a modest proposal that a mathematician and an economist write a short paper together
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