Julian Barbour
| Julian Barbour | |
|---|---|
| Born | 1937 |
| Residence | Oxfordshire |
| Citizenship | British |
| Fields | physics |
| Alma mater | University of Cologne |
| Known for | Time as illusion |
Julian Barbour (born 1937) is a British physicist with research interests in quantum gravity and the history of science.
Since receiving his Ph.D. degree on the foundations of Einstein's general theory of relativity at the University of Cologne in 1968, Barbour has supported himself and his family without an academic position, working part-time as a translator. He resides near Banbury, England.[1]
Contents |
[edit] Timeless physics
His 1999 The End of Time advances timeless physics: the controversial view that time, as we perceive it, does not exist as anything other than an illusion, and that a number of problems in physical theory arise from assuming that it does exist. He argues that we have no evidence of the past other than our memory of it, and no evidence of the future other than our belief in it. "Change merely creates an illusion of time, with each individual moment existing in its own right, complete and whole." He calls these moments "Nows". It is all an illusion: there is no motion and no change. He argues that the illusion of time is what we interpret through what he calls "time capsules," which are "any fixed pattern that creates or encodes the appearance of motion, change or history."
Barbour's theory goes further in scepticism than the block universe theory, since it denies not only the passage of time, but the existence of an external dimension of time. Physics orders "Nows" by their inherent similarity to each other. That ordering is what we conventionally call a time ordering, but does not come about from "Nows" occurring at specific times, since they do not occur, nor does it come about from their existing unchangingly along the time-axis of a block universe, but it is rather derived from their actual content. (In fact, the emergent ordering is probably not the single line of conventional time, but a branching structure like that of many worlds theory).
The philosopher J. M. E. McTaggart reached a similar conclusion in his 1908 The Unreality of Time. And in one of his last letters, Einstein wrote "People like us, who believe in physics, know that the distinction between past, present and future is only a stubborn, persistent illusion."[2]
[edit] Machian dynamics
Barbour also researches Machian physics, a related field. The Machian approach requires physics to be constructed from directly observable quantities. In standard analytical dynamics a system's future evolution can be determined from a state consisting of particle positions and momenta (or instantaneous velocities). The Machian approach eschews the momenta/instantaneous velocities, which are not directly observable, and so needs more than one "snapshot" consisting of positions only.[3] This relates to the idea of snapshots, or "Nows" in Barbour's thinking on time.[4]
[edit] Books
[edit] Sole author
- 1999. The End of Time: The Next Revolution in our Understanding of the Universe. Oxford Univ. Press. ISBN 0-297-81985-2; ISBN 0-19-511729-8 (paperback: ISBN 0-7538-1020-4)
- 2001. The Discovery of Dynamics: A Study from a Machian Point of View of the Discovery and the Structure of Dynamical Theories. ISBN 0-19-513202-5
- 2006. Absolute or Relative Motion?. ISBN 0-19-513203-3. Paperback reprinting of The Discovery of Dynamics.
[edit] Co-author
- 1982 (with B. Bertotti). Mach's Principle and the Structure of Dynamical Theories.
- 1994 (with Vladimir Pavlovich Vizgin) Unified Field Theories in the First Third of the 20th Century . ISBN 0-8176-2679-4.
- 1996 (with Herbert Pfister) Mach's Principle: From Newton's Bucket to Quantum Gravity. Birkhaueser. ISBN 0-8176-3823-7.
[edit] Scientific work by others bearing on Barbour's theories
- Anderson, Edward (2004) "Geometrodynamics: Spacetime or space?" Ph.D. thesis, University of London.
- -------- (2007) "On the recovery of Geometrodynamics from two different sets of first principles," Stud. Hist. Philos. Mod. Phys. 38: 15.
- Baierlein, R. F., D. H. Sharp, and John A. Wheeler (1962) "Three dimensional geometry as the carrier of information about time," Phys. Rev. 126: 1864-1865.
- Max Tegmark (2008) "The Mathematical Universe," Found. Phys. 38: 101-150.
- Wolpert, D. H. (1992) "Memory Systems, Computation, and The Second Law of Thermodynamics," International Journal of Theoretical Physics 31: 743-785. Barbour argues that this article supports his view of the illusory nature of time.
Barbour is cited in two books by Lee Smolin, his (1997) Three Roads to Quantum Gravity (pp. 119–121, 131) and his (2006) The Trouble with Physics (pp. 321–22).
[edit] References
- ^ "Julian Barbour - Contact". http://www.platonia.com/contact.html. Retrieved 1 October 2011.
- ^ Barry Parker, Lori Scoffield, Cosmic Time Travel: A Scientific Odyssey. Basic Books, 2001, p.v
- ^ Nature of Time
- ^ [It is utterly beyond our power to measure the changes of things by time ... time is an abstraction at which we arrive by means of the changes of things; made because we are not restricted to any one definite measure, all being interconnected. Mach himself was a sceptic about time: "It is utterly beyond our power to measure the changes of things by time ... time is an abstraction at which we arrive by means of the changes of things; made because we are not restricted to any one definite measure, all being interconnected."]
[edit] External links
- Julian Barbour's website.
- The End Of Time: A Talk With Julian Barbour
- Discover December 2000 From Here to Eternity
- Killing Time A 25-minute feature about the idea that time is an illusion, filmed by Dutch TV in December 1999 and first shown early in 2000
- Physics World profile
- The End of Time, Chapter One. (Requires free registration.)
- Video (with mp3 available) of Barbour discussion on Bloggingheads.tv
