207 of 221 people found the following review helpful:
3.0 out of 5 stars
The End of Time?, May 7, 2000
This review is from: The End of Time: The Next Revolution in Physics (Hardcover)
There are, historically speaking, only two concepts of time.
The first is the Space+Time vision of Kant, Newton, etc., with two small modifications. One is that of Einstein Time + Space are fused into the idea of Space-time. In Relativity theory Space-time can be 'cut' by a 'now'-plane in different ways, under different angles, so that simultaneity is no longer absolute, but dependent on the state of motion. But this vision is just a further mathematical elaboration of Space + Time, and does not contain any essential new insight into time itself.
The second minor modification is implicit in Quantum Mechanics. One of the four famous Heisenberg relations dE * dt > h implies, that 'now' is not 'absolute, and 'infinitely small', as commonly is believed, but has an extension that depends on the energy content of any existing objects. The more mass the object has, the more energy it has, (through E = mc2) and therefore the smaller its 'now'-interval is. This implies, that the 'now' of different objects is different; dependent on how much energy they consist of. From it you can explain how come that electrons that spin around these atoms do not radiate electromagnetic radiation. For if the time they need to revolve around the atom is equal to the 'now' interval, they essentially do not have the 'time' to complete that movement, so that, in a sense, you can say that they do not move. For if they do not move, they do not accelerate, and therefore do not radiate.
The second vision on time is the Leibniz vision. According to Leibniz, time is 'not really existing', but it is the conceptual order that our minds puts on existence. It is an ordering imposed on existence in terms of 'sooner and later'. In a philosophical sense this implies, that past, present, and future all `really exist'.
All of physics is based on the Space + Time vision. Newton used it, Einstein used it, Quantum Mechanics is based on it. Therefore physics has not changed the understanding of time significantly.
Basically, what Julian Barbour does, is nothing less than a total reconstruction of the whole of physics, based on the Leibniz vision of time. He first shows how classical physics can then be understood. Then he moves on to do the same with the special and general theories of relativity of Einstein. After having done that, he even moves on to quantum mechanics.
Does he succeed? I think he does. As such the book is very interesting. Next to these attempts, the book contains some interesting insights that only indirectly relate to time. Barbour shows, for example, that it is possible to integrate the two different visions of Newton and Leibniz about space by using Mach's principle. I find this part of the book the most fascinating I have ever read on the subject.
The only objection about Julian Barbour's approach is, essentially, the same you can rise against the Leibniz view of time as such. Philosophically speaking, if you begin by assuming that there is no real change, and that all change is `illusion', only `existing in the mind', then you have to explain how this `illusion' can arise, without introducing movement ANYWHERE. All such attempts have failed. To give an example: if we go to the cinema, to see `a picture', then what we see on the screen definitely `appears to move'. We all know, however, that the `the picture' consist of a lot of pictures that are all static. The movie projector, so to speak, creates the `illusion of movement' by showing all of these pictures `in succession', i.e., in time. It is able to do this, because it `operates in time'. In this way, change, and therefore time, is introduced `through the back door' so to speak. Besides, the static pictures themselves are a recording made of movements that have actually taking place. Therefore you can say, that the pictures are the RESULT of movements in the past, and not themselves identical with these movements. I think that the whole Leibniz vision on time is based on an inability to make exactly this distinction between movement and the result(s) of movement.
Physics is about finding answers to our questions. Philosophy is about understanding the questions first. Sound physics should therefore be preceded by sound philosophy. Julian Barbour's book is very strong in its physics department, giving at times very original insights. However, it is very weak in its philosophy. In fact, a philosophical treatment of a clarification of what we mean by the question: `what is time?' is almost missing in the book. The book goes straight to physics. Julian Barbour therefore fails to see, that the above `projection example' is a basic flaw in every explanation of time that is based on Leibniz philosophy. In other words, if you believe that Leibniz vision on time makes sense, then Julian Barbour shows how physics can be understood in terms of it. But if you think, as I do, that the Leibniz vision on time itself contains a basic flaw, then Julian Barbour's book fails to address this. For the book is primarily about the physics of time, not the metaphysics of time.
Conclusion: Do not expect, to find an explanation in this book how, philosophically speaking, `change' can be understood in terms of `the non-changing'. For it barely touches on this question. The only part of some awareness of this more basic problem of time I found in the book is by the idea of what Julian Barbour calls: `ephemeris time'. Essentially this idea of `ephemeris time' starts with the insight, that to understand what time is no more is required than an understanding of change. Ephemeris time follows from this as the ultimate result of change comparisons, through the use of the laws of physics that connect all changes with each other. This `program' is similar to an explanation whereby space can be seen as the ultimate result of length comparisons.
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54 of 57 people found the following review helpful:
4.0 out of 5 stars
Each petty pace.. to the last syllable of recorded time..., February 23, 2000
This review is from: The End of Time: The Next Revolution in Physics (Hardcover)
This is a complex and provocative field. I believe Mr. Barbour was also a Russian translator, and he clearly relishes mind games. The book is written primarily for physicists who are well-versed in quantum theory, eigenstates, Planck mass, Schrodinger's Q, Einstein, Mach, Leibnitz, Dirac, Minkowski, etc.. On Page 308 he states: "This book has been one long, sustained effort to shed redundant concepts". Barbour only gets to the heart of the issue in Chapter 15 after a long preamble of atom-splitting arguments. The re-dissection leads one into a reductio ad absurdum, where it goes beyond the bounds of (human) meaning, the Taoist domain of "everything is everything", where all analogies are inadequate. Basically he says the only way to unite macro-physics and quantum physics is to delete the whole notion of Time. I feel that the final chapter is weak, when he could have written it in a highly sensational manner. Is this just British understatement? Occasionally he seems to say Time is non-existent, but at other points, he proposes that it is time DIRECTIONALITY that is the illusion. All this is totally counter-intuitive but we are used to this by now. He claims all matter is governed by wave-functions that ping-pong back and forth in a kind of "phase-lock" and create frames-per-second mirages of motion and time or random configurations that are effectively timeless and directionless. There is no past or future as such (see Page 262) only "instants in time". Humans are totally beguiled by their earthbound reality that (appears to) move at a mere 70 frames/second, so how can they ever expect to gain command of near-light-speed microcosmic worlds of quantum particles? Barbour sees history as a collection of "time capsules" or "nows" which exist almost simultaneously in different regions of an eternal present which he calls Platonia. This "continent" is in "quantum stasis" (Page 305). Bizarre red, green and blue "mists" represent the unresolved areas of illusory becoming-ness that cannot be accessed directly. In these, he sees a shadowy deterministic force at work (quantum-ism) that forges the destiny of all things by moving along the lines of least resistance (maximum probability). In effect, this shadow-force is the one that replaces and mimics old Father Time in Barbour's universe. He also postulates (p.277) that particles can be auto-created out of Gaussian waves, in a kind of voodoo science, yet to be found.
Time can be defined in so many ways that writing about it is a near impossibility. Time is a self-referential human artifice which is utterly meaningless in quantum physical terms.
Denial of Time presents Barbour with some tricky problems e.g: the expanding universe, animal evolution, cause and effect, birds in flight etc..To explain the illusion of an expanding universe, he posits that Platonia has an "Alpha point" which is equivalent to the Big Bang, but is not of course the start-point in any real sense. There is also no Omega point.
Denial of Motion is the most controversial of Barbour's ideas and he admits this on page 261 - "This is the point at which my ideas part company with (comparative) orthodoxy."
I think Barbour is on the right scent. He needs more orderliness and decisiveness.
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176 of 200 people found the following review helpful:
4.0 out of 5 stars
Frustrating Read, March 20, 2000
This review is from: The End of Time: The Next Revolution in Physics (Hardcover)
There are currently several books dealing with new theories in physics, they are fascinating but I found the "End of Time" a bit disappointing after all the newspaper hype. What I want in a book of this type are three things, firstly to be educated on the general theoretical background, entertainingly presented the history of the subject up to the present day, secondly the author must, as succinctly as possible, explain their theory; show where it supports and where it overturns conventional ideas. Finally the books must present conclusions, sketch out the likely impact of the new concept. The "End of Time" devotes many pages to arguments in favour of the author's thesis, in a way that will bore the general reader but is unlikely to convince the physicist. Near the end of the book my feeling was ok ok you win, just tell me the implications, but that's the problem, the author refuses to speculate, possibly on the spurious grounds that predictions are impossible in a world without time. In summary a long, confusing and eventually a frustrating read. If you want to see how a book of this type should be handled read the unbelievably good "The Inflationary Universe" by Alan H. Guth.
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