It has also been pointed out to me by several email correspondents that there is a clear anticipation of some of my ideas about time in Fred Hoyle’s novel October the First Is Too Late, which Paul Davies discusses in his About Time. Sir Fred’s ‘pigeonholes’ are essentially my time capsules. American reviewers and correspondents also noted a similarity with the philosophy of time that underlies Kurt Vonnegut’s Slaughterhouse Five. Having now read the book, I can confirm that this is the case. Of course, as I make clear in the text, John Bell also formulated the idea of time capsules (without giving them any name) quite clearly long before me. Another correspondent, Andrew Clifton, regretted that I had not devoted at least a few words to demolishing the idea that there really is a ‘moving present’. I think he was right. Happily, David Deutsch has done the job very well in his The Fabric of Reality.
I should also like to thank Damien Broderick, who has reviewed my book for The Australian, for drawing my attention to various misprints.
It is also now clear to me that in the body of the text I should have said more about possible ways in which my ideas could be refuted. A theory is no use to science unless it is capable of disproof. In the email exchange with Fay Dowker, I did mention the possibility of mathematical disproof of my conjecture that the Wheeler—DeWitt equation concentrates its solutions on time capsules. However, I think that (in normal parlance) that might take decades. Something that might occur much sooner is a completely convincing definitive form of superstring theory (or some other unified theory) that reintroduces an external time (string theory does currently use background structures). That would kill my idea. My own feeling is that in fact superstring theory will, if and when it is found, turn out to be timeless.
Then there is one other quite different way in which my ideas could be disproved. This is if experimental evidence can be found that shows collapse of the quantum wave function to be a real physical process. In this connection, I should like to mention especially an experiment proposed by Roger Penrose to test this very possibility. He is developing it in collaboration with Anton Zeilinger, the Austrian physicist based in Vienna, who has performed so many incredibly beautiful quantum experiments. Penrose, very understandably, finds the many-worlds interpretation of quantum mechanics extremely hard to accept (see my comments about the death of Diana), and with great persistence is trying to find a way round it. He has certainly identified the greatest single issue in modern physics. If his experiment, which could perhaps be performed within a decade, works out in the way he hopes, it will be a huge development and destroy my approach (because it will show that quantum mechanics does not hold macroscopically). The volume containing my paper (Barbour 2000) also contains Penrose’s most important paper on the subject, and also a related paper by Joy Christian, who was a student of Abner Shimony. Joy, following Abner (see my Epilogue), is trying to establish transience as a real physical thing. I think that if collapse of the wave function could be demonstrated as a real physical phenomenon, that would be true demonstration of something that one might call transience.
JB
January 2001
FURTHER READING
Barrow, John, 1992, Theories of Everything, Oxford University Press, Oxford.
Barrow, John and Tipler, Frank, 1986, The Anthropic Cosmological Anthropic Principle, Clarendon Press, Oxford.
Bondi, Hermann, 1962, Relativity and Common Sense: A New Approach to Einstein, Dover, New York.
Coleman, James, 1954, Relativity for the Layman, William-Frederick Press, New York (1990, Penguin, London).
Coveney, Peter and Highfield, Roger, 1991, The Arrow of Time, Flamingo, London.
Davies, Paul, 1991, The Mind of God, Simon & Schuster, New York.
Davies, Paul, 1995, About Time: Einstein’s Unfinished Revolution, Penguin Press, London.
Deutsch, David, 1997, The Fabric of Reality, Penguin Press, London.
Eddington, Arthur, 1920, Space, Time and Gravitation, Cambridge University Press, Cambridge.
Einstein, Albert, 1960, Relativity: The Special and the General Theory. A Popular Exposition, Routledge, London.
Greene, Brian, 1999, The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory, Vintage Books, New York.
Gribbin, John, 1984, In Search of Schrödinger’s Cat: Quantum Physics and Reality, Corgi, London.
Guth, Alan H., 1997, The Inflationary Universe: The Quest for a New Theory of Cosmic Origins, Perseus Books Group, New York.
Lippincott, Kristen, Eco, Umberto, Gombrich, E. H. et al., 1999, The Story of Time, Merrell Holberton, London. [This is a splendid book on the most diverse aspects of time in culture and science.]
Lockwood, Michael, 1989, Mind, Brain and the Quantum, Basil Blackwell, Oxford.
Novikov, Igor, 1998, The River of Time, Cambridge University Press, Cambridge.
Penrose, Roger, 1989, The Emperor’s New Mind: Concerning Computers, Minds, and the Laws of Physics, Oxford University Press, Oxford.
Price, Huw, 1996, Time’s Arrow and Archimedes’ Point, Oxford University Press, New York.
Rees, Martin, 1997, Before the Beginning: Our Universe and Others, Simon & Schuster, London.
Rees, Martin, 1999, Just Six Numbers: The Deep Forces that Shape the Universe, Weidenfeld & Nicolson, London.
Smolin, Lee, 1997, The Life of the Cosmos, Weidenfeld & Nicolson, London (Oxford University Press, New York).
Thorne, Kip, 1994, Black Holes and Time Warps: Einstein’s Outrageous Legacy, Norton, New York.
Tipler, Frank, 1995, The Physics of Immortality, Doubleday, New York.
Weinberg, Steven, 1977, The First Three Minutes, Basic Books, New York (André Deutsch, London).
Weinberg, Steven, 1993, Dreams of a Final Theory: The Search for the Fundamental Laws of Nature, Vintage, London.
Wheeler, John Archibald, 1990, A Journey into Gravity and Spacetime, Scientific American Library, New York.
Will, Clifford, 1986, Was Einstein Right?, Basic Books, New York.
BIBLIOGRAPHY
Arnowitt, R., Deser, S. and Misner, C.W., 1962, ‘The dynamics of general relativity’, in Gravitation: An Introduction to Current Research, L. Witten (ed.), Wiley, New York.
Baierlein, R.F., Sharp, D.H. and Wheeler, J.A., 1962, ‘Three-dimensional geometry as a carrier of information about time’, Physical Review, 126, 1864.
Banks, T., 1985, ‘TCP, quantum gravity, the cosmological constant and all that . . .’, Nuclear Physics, B249, 332.
Barbour, J.B., 1989, Absolute or Relative Motion? Vol. 1: The Discovery of Dynamics, Cambridge University Press, Cambridge; reprinted as the paperback The Discovery of Dynamics, Oxford University Press, New York (2001).