, Volume 102, Issue 2, pp 235–266

Time, quantum mechanics, and decoherence

  • Simon Saunders


State-reduction and the notion of “actuality” are compared to “passage” through time and the notion of “the present”; already in classical relativity the latter give rise to difficulties. The solution proposed here is to treat both tense and value-definiteness as relational properties or “facts as relations”; likewise the notions of change and probability. In both cases “essential” characteristics are absent: temporal relations are tenselessly true; probabilistic relations are deterministically true.

The basic ideas go back to Everett, although the technical development makes use of the decoherent histories theory of Griffiths, Omnès, and Gell-Mann and Hartle. Alternative interpretations of the decoherent histories framework are also considered.


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  1. Albert, D.: 1992,Quantum Mechanics and Experience, Harvard University Press, Cambridge.Google Scholar
  2. Albert, D. and B. Loewer: 1988, ‘Interpreting the Many-Worlds Interpretation’,Synthese 77, 195–213.Google Scholar
  3. Bell, J.: 1987,Speakable and Unspeakable in Quantum Mechanics, Cambridge, Cambridge University Press.Google Scholar
  4. Belnap, N.: 1992, ‘Branching Space-Time’,Synthese 92, 385–434.Google Scholar
  5. Bohr, N.: 1934,Atomic Theory and the Description of Nature, Cambridge University Press, Cambridge.Google Scholar
  6. Bohr, N.: 1935, ‘Can Quantum Mechanical Description of Reality be Considered Incomplete?’,Physical Review 48, 697–702.Google Scholar
  7. Bohr, N.: 1949, ‘Discussion with Einstein on Epistemological Problems in Atomic Physics’, in Schilpp (1949, pp. 201–41).Google Scholar
  8. Daneri, A., A. Loinger, and G. Prosperi: 1962, ‘Quantum Theory of Measurement and Ergodicity Conditions’,Nuclear Physics 33, 297–319.Google Scholar
  9. Davies, P. C. W.: 1981, ‘Time and Reality’, in R. Healey (ed.),Reduction, Time and Reality, Cambridge University Press, Cambridge, pp. 63–78.Google Scholar
  10. Davis, M.: 1977, ‘A Relativity Principle in Quantum Mechanics’,International Journal of Theoretical Physics 16, 867–74.Google Scholar
  11. Deutsch, D.: 1985, ‘Quantum Theory as a Universal Physical Theory’,International Journal of Theoretical Physics 24, 1–41Google Scholar
  12. Deutsch, D.: 1986, ‘Three Connections between Everett's Interpretation and Experiment’ in R. Penrose and C. Isham (eds.),Quantum Concepts in Space and Time, Clarendon Press, Oxford, pp. 215–25.Google Scholar
  13. DeWitt, B.: 1970,Physics Today 23(9); reprinted in DeWitt and Graham, 1973, pp. 155–67.Google Scholar
  14. DeWitt, B.: 1993, ‘How Does the Classical World Emerge from the Wave Function?’, in F. Mansouri and J. J. Scanio (eds.),Topics on Quantum Gravity and Beyond, World Scientific, Singapore.Google Scholar
  15. DeWitt, B. and N. Graham: 1973,The Many-Worlds Interpretation of Quantum Mechanics, Princeton University Press, Princeton.Google Scholar
  16. Dieks, D.: 1989, ‘Quantum Mechanics without the Projection Postulate and its Realistic Interpretation’,Foundations of Physics,19, 1397–423.Google Scholar
  17. Dowker, H. F. and J. J. Halliwell: 1992, ‘Quantum Mechanics of History: The Decoherence Functional in Quantum Mechanics’,Physical Review D46, 1580–609.Google Scholar
  18. Dowrick, N. J.: 1993, ‘Path Integrals and the GRW Model’, preprint, Department of Nuclear Physics, Oxford University.Google Scholar
  19. Dummett, M.: 1969, ‘The Reality of the Past’, inTruth and Other Enigmas, pp. 358–74, Harvard University Press, Cambridge.Google Scholar
  20. Everett III, H.: 1957, ‘Relative State Formulation of Quantum Mechanics’,Reviews of Modern Physics 29, 454–62, reprinted in DeWitt and Graham, 1973, pp. 141–50.Google Scholar
  21. Fahri E., J. Goldstone and S. Gutman: 1989, ‘How Probability Arises in Quantum Mechanics’,Annals of Physics 192, 368–82.Google Scholar
  22. Finkelstein, D.: 1963, ‘The Logic of Quantum Physics’,Transactions of the New York Academy of Science 25, 621–37.Google Scholar
  23. Finkelstein, J.: 1993, ‘Definition of Decoherence’,Physical Review D47, 5430–3.Google Scholar
  24. Gell-Mann, M. and J. B. Hartle: 1990, ‘Quantum Mechanics in the Light of Quantum Cosmology’, in W. H. Zurek (ed.),Complexity, Entropy, and the Physics of Information, Reading, Addison-Wesley, pp. 425–59.Google Scholar
  25. Gell-Mann, M. and J. B. Hartle: 1993, ‘Classical Equations for Quantum Systems’,Physical Review D47, 3345–82.Google Scholar
  26. Geroch, R.: 1984, ‘The Everett Interpretation’,Noûs 18, 617–33.Google Scholar
  27. Gödel, K.: 1949, ‘A Remark about the Relationship between Relativity Theory and Idealistic Philosophy’, in Schilpp (1949, pp. 555–63).Google Scholar
  28. Graham, N.: 1973, ‘The Measurement of Relative Frequency’, in DeWitt and Graham (1973, pp. 229–553).Google Scholar
  29. Griffiths, R.: 1984, ‘Consistent Histories and the Interpretation of Quantum Mechanics’,Journal of Statistical Physics 36, 219–72.Google Scholar
  30. Grünbaum, A.: 1971, ‘The Meaning of Time’, in E. Freeman and W. Sellers (eds.),Basic Issues in the Philosophy of Time, Open Court, La Salle, pp. 195–228.Google Scholar
  31. Grünbaum, A.: 1973,Philosophical Problems of Space and Time, Chap. 10, Boston Studies in the Philosophy of Science, Vol. XII, D. Reidel, Dordrecht.Google Scholar
  32. Halliwell, J. J.: 1994, ‘Aspects of the Decoherent Histories Approach to Quantum Mechanics’, in L. Diósi (ed.),Stochastic Evolution of Quantum States in Open Systems and in Measurement Processes, World Scientific, Singapore, pp. 54–68.Google Scholar
  33. Hartle, J. B.: 1968, ‘Quantum Mechanics of Individual Systems’,American Journal of Physics 36, 704–12.Google Scholar
  34. Hartle, J. B.: 1993, ‘Reduction of the State Vector and Limitations on Measurement in the Quantum Mechanics of Closed Systems’, preprint UCSBTH-92-16.Google Scholar
  35. Healey, R.: 1984, ‘How Many Worlds?’,Noûs 18, 591–616.Google Scholar
  36. Heisenberg, W.: 1959,Physics and Philosophy: The Revolution in Modern Science, Allen and Unwin, London.Google Scholar
  37. Hepp, K.: 1972, ‘Quantum Theory of Measurement and Macroscopic Observables’,Helvatica Physica Acta 45, 237–48.Google Scholar
  38. Isham, C. J. and N. Linden, 1994: ‘Quantum Temporal Logic and Decoherence Functionals in the Histories Approach to Generalized Quantum Theory’, Imperial College Preprint, Imperial /TP/93–94/35.Google Scholar
  39. Jammer, M.: 1974,The Philosophy of Quantum Mechanics, Wiley, New York.Google Scholar
  40. Joos, E. and H. D. Zeh: 1985, ‘The Emergence of Classical Properties through Interaction with the Environment’,Zeitschrift für Physik B59, 223.Google Scholar
  41. Kent, A.: 1990, ‘Against Many-Worlds Interpretations’,International Journal of Modern Physics A5, 1745–62.Google Scholar
  42. Kuchař, K. V.: 1992, ‘Time and Interpretations of Quantum Gravity’, in G. Kunstatter, D. Vincent and J. Williams (eds.),Proceedings of the 4th Canadian Conference on General Relativity and Relativistic Astrophysics, World Scientific, Singapore.Google Scholar
  43. Lockwood, M.: 1989, ‘Mind, Brain, and the Quantum, Basil Blackwell, Oxford.Google Scholar
  44. Lockwood, M.: 1992, ‘What Schrödinger Should have Learnt from his Cat’, in M. Bitbol and O. Darrigol (eds.), Erwin Schrödinger: Philosophy and the Birth of Quantum Mechanics, Editions Frontières, Cedex, pp. 363–84.Google Scholar
  45. London F. and E. Bauer: 1939,La théorie de l'observation en mécanique quantique, No. 775 ofActualités sceintifiques et industrielles, P. Langevin (ed.), Hermann, Paris; translated in Wheeler and Zurek, 1983, pp. 217–59.Google Scholar
  46. Maudlin, T.: 1994,Quantum Non-Locality and Relativity, Blackwell, Oxford.Google Scholar
  47. Maxwell, N.: 1985, ‘Are Probabilism and Special Relativity Incompatible?’,Philosophy of Science 52, 23–43.Google Scholar
  48. McCall, S.: 1976, ‘Objective Time-Flow’,Philosophy of Science 43, 337–62.Google Scholar
  49. Murdoch, D.: 1987, ‘Neils Bohr's Philosophy of Physics, Cambridge University Press, Cambridge.Google Scholar
  50. Ochs, W.: 1977, ‘On the Strong Law of Large Numbers in Quantum Probability Theory’,Journal of Philosophical Logic 6, 473–80.Google Scholar
  51. Omnès, R.: 1988,Journal of Statistical Physics 53, 933.Google Scholar
  52. Omnès, R.: 1990, ‘From Hilbert Space to Common Sense: A Synthesis of Recent Progress in the Interpretation of Quantum Mechanics’,Annals of Physics (N.Y.)20(1), 354–447.Google Scholar
  53. Omnès, R.: 1992, ‘Consistent Interpretations of Quantum Mechanics’,Reviews of Modern Physics 64, 339–82.Google Scholar
  54. Parfit, D.: 1984,Reasons and Persons, Oxford University Press, Oxford.Google Scholar
  55. Pearle, P.: 1990, ‘Towards a Relativistic Theory of Statevector Reduction’, in A. Miller (ed.),Sixty-Two Years of Uncertainty, Plenum Press, New York, pp. 193–214.Google Scholar
  56. Putnam, H.: 1967, ‘Time and Physical Geometry’,Journal of Philosophy 64, 240–47, reprinted inPhilosophical Papers. Vol. 1, Cambridge University Press, Cambridge, 1975, pp. 198–205.Google Scholar
  57. Putnam, H.: 1981, ‘Answer to a Question from Nancy Cartwright’,Erkenntnis 16, 407–10.Google Scholar
  58. Rimini, A.: 1992, ‘A Framework for a Relativistic Theory of State Reduction’,Foundations of Physics Letters 5, 499–515.Google Scholar
  59. Saunders, S.: 1993a, ‘Decoherence, Relative States, and Evolutionary Adaptation’,Foundations of Physics 23, 1553–85.Google Scholar
  60. Saunders, S.: 1993b, ‘Decoherence and Evolutionary Adaptation’,Physics Letters A 184, 1–5.Google Scholar
  61. Saunders, S.: 1994, ‘Remarks on Decoherent Histories Theory and the Problem of Measurement’, in L. Diósi (ed.),Stochastic Evolution of Quantum States in Open Systems and in Measurement Processes, World Scientific, Singapore, pp. 94–105.Google Scholar
  62. Schilpp, A. (ed.): 1949,Albert Einstein, Philosopher-Scientist, Open Court, La Salle.Google Scholar
  63. Schrödinger, E.: 1935, ‘Die Gegenwärtige Situation in der Quantenmechanik’,Die Naturwissenschaften 23, 807–12, 823–28, 844–49; translated in Wheeler and Zurek (1983, pp. 152–67).Google Scholar
  64. Shimony, A.: 1993, ‘The Transient Now’, inSearch for a Naturalistic World View, Vol. 2, Cambridge University Press, Cambridge, pp. 271–87.Google Scholar
  65. Squires, E.: 1990,Conscious Mind in the Physical World, Adam Hilger, New York.Google Scholar
  66. Stein, H.: 1968, ‘On Einstein-Minkowski Space-Time’,Journal of Philosophy 65, 5–23.Google Scholar
  67. Stein, H.: 1984, ‘The Everett Interpretation of Quantum Mechanics: Many Worlds or None?’,Noûs 18, 635–52.Google Scholar
  68. Stein, H.: 1991, ‘On Relativity Theory and the Openness of the Future’,Philosophy of Science 58, 147–67.Google Scholar
  69. Wheeler, J. A. and W. H. Zurek (eds.): 1983,Quantum Theory and Measurement, Princeton University Press, Princeton.Google Scholar
  70. Wright, C.: 1993,Realism, Meaning, and Truth, 2nd. Ed., Blackwells, Oxford.Google Scholar
  71. Yourgrau, P.: 1991,The Disappearance of Time; Kurt Gödel and the Idealistic Tradition in Philosophy, Cambridge University Press, Cambridge.Google Scholar
  72. Zeh, H. D.: 1992,The Physical Basis for the Direction of Time, 2nd. Ed., Springer-Verlag, Berlin.Google Scholar
  73. Zeh, H. D.: 1993, ‘There are No Quantum Jumps, Nor are there Particles’,Physics Letters A172, 189–92.Google Scholar
  74. Zelicovici, D.: 1986, ‘A (Dis)Solution of McTaggart's Paradox’,Ratio 28, 175–95.Google Scholar
  75. Zurek, W. H. (ed.): 1990,Complexity, Entropy, and the Physics of Information, Addison-Wesley, Reading.Google Scholar
  76. Zurek, W. H.: 1991, ‘Decoherence and the Transition from Quantum to Classical’,Physics Today 44(10), 36–44.Google Scholar
  77. Zurek, W. H.: 1993, ‘Negotiating the Tricky Border Between Quantum and Classical’,Physics Today 46(4), 13–15, 81–90.Google Scholar
  78. Zurek, W. H.: 1994, ‘Preferred States, Predictability, Classicality, and the Environment-Induced Decoherence’, to appear in J. J. Halliwell, J. Perez-Mercader, and W. H. Zurek (eds.),The Physical Origins of Time Asymmetry, Cambridge University Press, Cambridge.Google Scholar

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • Simon Saunders
    • 1
  1. 1.Department of PhilosophHarvard UniversityCambridgeUSA

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