Customer Reviews

The End of Time: The Next Revolution in Physics

5 star:		(13)
4 star:		(16)
3 star:		(7)
2 star:		(12)
1 star:		(14)

 

 

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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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.

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.

The history of science has been the explanation of phenomena that were previously the domain of philosophers, and this is true of Julian Barbour's book, "The end of Time". Barbour's simple idea is that time does not exist in nature. But since time is explicitly entwined with motion, Barbour faces a much more monumental task--banishing the very motion responsible for the abstract concept of time itself. This he does quite convincingly. Newton believed motion was relative to absolute space; Einstein proposed that space and time must be considered together; and Barbour calls space and time redundant. There is nothing that lies within our physical universe, no internal change relative to the universe as a whole. Rather, all that we "see" as objects in motion "within" the universe are in fact part of the whole universe itself. Movement is simply different configurations of the holistic universe in total. Therefore, there is no motion, and by defintion no time. This is the intuitve concept that Barbour presents. Though I believe it could have been presented in a shorter format, it is certainly worth the read.

Of course people may have trouble with this book! It grapples with one of the most counter-intuitive hypotheses ever pondered. Unsurprisingly, befuddled readers will readily point fingers at the author's "poor exposition". When someone fails to understand Joyce or Faulkner, it's the reader's fault, but when someone can't understand a science author, then it's the writer's fault....

The fact is that if the author (or anyone else, for that matter) understood the nature of time well enough to spoon-feed us with a crystal-clear, airtight argument (together with its attendant implications, as some readers demand) such insight would already be in the news as the single greatest breakthrough in the history of physics. As it is, the ideas presented in the book are speculative and unstructured. They may even be flawed. So what? To date, they constitute one of the few (if not the only) non-technical discussions of current thoughts on the most baffling aspect of physical reality.

This book is clearly meant for those who want to "read about it first", whenever some interesting idea first appears in print, no matter how undigested. As for those readers who would rather wait for the Discovery-Channel version of everything, their stance is legitimate, but can hardly be blamed on a book.

A great introduction to Shape Space but not a very good theory. That is how I would be inclined to describe this book. It's major shortcoming is the refutation to Barbour's theory by Abner Shimony (available in The Geometric Universe). This complete and utter destruction of the timelessness theory is given a very brief spot in the notes for CHAPTER 3: A TIMELESS WORLD (p. 343).

By not giving the proper credit to Shimony's theory, Barbour does himself in. Later the book uses a method to prove timelessness that Shimony has already proved is mere rhetoric.

As I read further and further on I also get the feeling Barbour really isn't exactly sure what his theory really is! He has difficulty upon difficulty even making it apparent to someone like me with a strong mathematics/physics background.

All in all the book is structured to prove itself correct while ignoring weather or not there is any evidence for it's correctness. A tough read I imagine for any beginner and filled with self-promotion especially repeated (and repeated and repeated) mentions of the author's website. A blatantly obvious attempt to mirror the success of The Emperor's New Mind. Yet it fails so badly at this that it is almost laughable. Instead of laughing however I imagine most readers will simply stop reading after the first few chapters. It gets three stars only because it is one of the best lay introductions to Shape Space in print.

Barbour's thesis is that time is an illusion, and doesn't really exist. According to Barbour, the universe is a timeless thing existing in configuration space; it doesn't "move through time," but rather exists as an infinitely dimensioned manifold (my word, not his, and I may not have accurately captured his meaning) in configuration space, where each point on the manifold represents the universe in a unique configuration.

Many of the key concepts in this timeless universe were developed by earlier scientists, particularly Mach. Indeed, one of the benefits of reading this book is the many historical highlights and anecdotes provided by the author. Even if you don't subscribe to his timeless universe hypothesis, the books background material in Newtonian dynamics, special and general relativity, and quantum mechanics makes it worth reading.

The first part of the book lays out general concepts, including the notion of configuration space. I particularly liked Barbour's method of using three points (a "universe" with just three points) as a metaphor for the timeless universe he imagines. In this simplified three-point universe one can define a history as just a path through configuration space - thus eliminating the need for a time variable (at least as far as describing a history is concerned, anyway).

One of the traps in both reading and writing this book is that the concept of time is so permanently ingrained into our minds that it seems impossible to discuss the issue without recourse to phraseology pregnant with the very thing (time) that Barbour says doesn't exist. His wording is literally dripping with time-impregnated words as he describes a timeless world. He understands, even apologizes for the problem - but it persists and was a source of distraction and confusion for me throughout the book.

I think the author does a better job of showing how to eliminate time (or at least think in terms of a timeless universe) within the context of Newtonian dynamics, than in a relativistic and quantum universe. The explanations from an Newtonian point of view are pretty straight forward, but as he progresses through special and general relativity, and on to quantum dynamics, the picture - and figures - become more sparse and (it seems) more dependent on speculation.

At an intuitive and philosophical level I find myself largely in agreement with Barbour. There's something weird about time. It doesn't quite fit. I've often caught myself toying with the notion that it's an illusion. On the other hand, we can measure it, and all our measurements seem to be consistent. It's hard to see how we can measure a second so precisely if it's just an illusion.

On another level I'm almost inclined to think the whole thing is based on semantics. After all, if someone told me that pain is an illusion - that it's really just electrical impulses transmitted to my brain - I'd reply that that's an explanation of what pain is, not an argument that it doesn't exist. Similarly, the universe may exist in timeless configuration space, but my consciousness certainly doesn't. Maybe what we mistook for the universe (and us) moving through time is really just us - our consciousness - moving through configuration space. We mistake our travel through configuration space as movement through time the same way someone floating down a river might mistakenly think the trees are moving past them, and they are just standing still. In fact, I wonder if that might be a characteristic of consciousness - something that moves through configuration space - and perhaps the "laws" of the universe look the way they do because our consciousness is constrained, by virtue of its existence, to travel through configuration space along histories (paths in configuration space) that have certain characteristics (increasing entropy, for example).

That's just speculation, of course, but that's what a lot of Barbour's book is, too; a lot of speculation. Not that that's particularly bad, it's just that, in the end, there's nothing really testable here to evaluate.

Oddly, the most succinct and lucid statement of Barbour's theory comes, not from him, but from a reader whose email he quotes in the footnotes at the end of the book: "All moments are simultaneous ... My conscious mind feeds them to me in a linear sequence strung out with a bunch of other moments in an illusion of a continuous flow of action." (p. 340, trade paperback edition) Barbour comments that this reader's views are "often very close to my own position."

I see two problems here. First, the hypothesis seems essentially solipsistic - it's not clear if it can ever be tested, proved, or disproved. Second, how can "my conscious mind feed these moments to me" in a world of total stasis, a world where everything is frozen and motionless? Either consciousness itself is exempt from the timelessness of the rest of the system (but Barbour seems to think it isn't) or consciousness, being part of a timeless reality, is frozen and unable to engage in any processes - including the process of "feeding" moments to me. In other words, if time is an illusion created by a filmstrip of single frames being run in our heads, then what is running the movie, and how can the movie run at all when nothing can move?

The theory seems to raise more questions than it answers. Still, questions are always valuable, so - three stars!

For the general reader who is neither mathematician nor physicist, this book is a real stretch, but what a great stretch it is! Barbour understands this and takes mostly successful pains to help us along. And just as the body feels invigorated and stronger after a good workout, so does the mind on finishing Barbour's book.

The central thesis is that the role played by time in physicists' descriptions of the world, has to go. Its departure will open the way to unifying the hitherto unbridgeable gap between classical physics and quantum physics. As Barbour explains with fascinating clarity, both are obviously correct and verified descriptions of how things work; they just don't mesh! This, for physicists who believe deeply in the unity of nature, is cause for deep frustration.

Any book that sets out to address the big questions about `the ultimate arena of the universe' is not without ambition. That is what led me forward through some tough going early on because, hey, if this guy is really about to advance a description of how the universe works, I want to hear it! Well, he delivers. For Barbour, time, or rather the experience of change and movement, which require time to be real, is an illusion created by the existence of an infinity of possible simultaneously-existing and unchanging `nows'. These nows are configurations of the complete universe in a multi-dimensional configuration-space. Quantum-probabilistic laws govern which nows are experienced, and all the laws of physics can be re-cast in terms of this version of how the universe works.

Put your reservations aside and consider the argument. It's persuasive. After all, our experience of history is only through records and memories, which of course are part of any now we experience. After all, we don't truly look `into the past'. We simply look at records and memories available to us at this instant, and in Barbour's thesis these indeed can reflect other nows, which are other places in the universe, but not other times. The corollary of this is that nothing moves, nothing changes, in this model of the universe. We don't travel from one now to the next and experience life like watching a movie made up of multiple still snapshots. We just are. The rest is illusion.

This last is where things don't quite work for this reader. What we are seeing is a heroic attempt to reconcile the way this thesis works as a piece of theoretical physics, with a macro-description of the facts of existence and human experience. Like other such attempts one encounters in this neighborhood of ideas, it hits the shoals of philosophy, not of science. Here's what I mean: movement and change are facts of existence. The role of science is to understand their nature, but it is not the role of science (nor philosophy) to deny that they exist. That's out of bounds. To put it another way: if you assert that movement and change as we experience them are illusory, what you have done is to redefine the meaning of the word `illusory' in a somewhat arbitrary way. Again, out of bounds. And it may just be that Barbour's physics is right, just his attempt to bring it back to a correspondence with our daily realities that is flawed.

So give this one a shot and stretch your mind!

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.