The End of Time: The Next Revolution in Our Understanding of the Universe

BlackOxford

Rating: really liked it
Plato Rules OK?

I suspect that most of us have thought at some point about the mystery of time. But very few have considered seriously what it might be. And only a handful, perhaps, could explain in a comprehensible way how time is constructed. And, I’m sure, there are less than a handful who with any plausibility deny its existence entirely - Julian Barbour is one of these. And he makes an interesting case.

According to Barbour, time is a constructive illusion, a concept without any extra-linguistic existence. We use it like a ‘god of the gaps’ to explain that for which we have no other theory. The illusion is the sensory equivalent of a flat earth or the appearance of instantaneous gravitational action at a distance. What we experience, or name as experience, is our interpretation of various states of entropy, a measure of the disorder of the cosmos.

Time then is really the feeling of progression from states of lower to states of higher entropy, from relative order to disorder. Such a concept might seem a scientific splitting of hairs, except that it has a profound implication: the ‘direction’ of time depends on what ‘side’ of successive entropy states one happens to be. Successive states might be ‘before’ or ‘after’ each other depending on the perspective of the conscious being involved. Since the past is always the domain of lesser entropy, time, the gradient of entropy, can run in opposite directions simultaneously. The past is a conjecture, a supposition made on the basis of incomplete information, not a fact.

Barbour believes that there are evolutionary reasons for our creation of the idea of time. We are programmed to detect ‘records’, sequences of entropic states, at the expense of other perceptual sensitivities. We are able to manipulate, really order, these records through consciousness to great effect in finding food, establishing social structures, in ‘anticipating’ consequences. In short, time is a survival tactic, an expediency which may no longer be expedient. What it is not is a physical reality.

Perhaps the principle reason I am attracted to Barbour’s theory (in addition to its sheer provocation) is that it vindicates much of Platonic thinking. Plato’s ‘forms’ for example have a credibility inside a timeless universe which had been lost in the methods of Aristotelian science. Instants, what Barbour calls Nows, are things. Space and time are not more fundamental than things, in which things mysteriously float; they are part of the ‘configuration’ of things as they exist. This highly technical term of configuration seems remarkably similar, if not equivalent, to the Platonic ‘eternal ideas’.

The End of Time is challenging, but not because Barbour’s exposition is flawed or interrupted by technical scientific and mathematical proof texts. It is challenging because it reveals the depth of presumption about the world that we carry around with us nonchalantly. Exposing these unwarranted presumptions is often a matter of confronting not just common sense but an entire culture of thought that has worked reasonably well. In a sense, what Barbour is doing is equivalent to Luther’s nailing of his theses on the door of Wittenberg Cathedral. Neither Luther nor Barbour could have a clear idea of the consequences. Nevertheless, they’re bound to be exciting.

Postscript: for a good short summary of much of Barbour see: https://www.lesswrong.com/posts/rrW7y...

To see how badly the subject can be written about, consult this academic text on time. Its lack of literary skill, I’ll wager, is matched by its opaqueness of thought: https://www.goodreads.com/review/show...

Manny

Rating: really liked it
People who read pop science books will know by now that the physics world is rather like that of Star Wars. The dominant String Theorists are the Empire; led by the Vader-like Ed Witten, they control the corrupt funding agencies and rule science with an iron fist. Ranged against them, we have the eccentric and charismatic Rebels. Lee Smolin's Periphery Institute is clearly the main Rebel base, and Peter Woit comes across as a typical Han Solo figure. I rather fancy Roger Penrose as Obi-Wan Kenobi and Fotini Markopoulou as Princess Leia. Luke Skywalker, alas, does not yet appear to have turned up. But I've got no doubts about Julian Barbour: he can't be anyone but Yoda. Even something of a physical resemblance, wouldn't you say?





You may have trouble with some of this book, but try reading it aloud in a Yoda voice and much will become clear. "Time, an illusion it is. Platonia, a relative configuration space it is. A blue mist, collect over Platonia it does." The blue mist, which plays a large part in the book, could be glossed as the quantum mechanical probability density function, but you may well prefer to think of it as the Force; the wave function's real and imaginary parts are the red and green mists.

I am afraid that my fluency in Yoda is limited, so I will reluctantly switch to English and leave the translation as an exercise to a more linguistically gifted reader. Joking aside, the opening part of Barbour's argument is very sensible. He starts by considering the question of what "time" is, and comes up with some good answers. He wants to go back to Mach's Principle, and think only about relative measurements: the example used though much of the book is "Triangle Space", a toy universe with two dimensions of space and one of time, which contains just three objects moving under the influence of gravity. He asks you to consider what you can do if you're just given snapshots of instants ("Nows") in Triangle Space, and shows how you can reconstruct the notion of time from them in a straightforward and pleasing way.

He takes this idea as his starting point, and then applies it to successively more complicated models of physics. It's easy to do it in Special Relativity. General Relativity is much harder, and he only sketches the argument. The problem is that a "Now" in General Relativity is a very slippery notion, since you can cut up space-time in infinitely many different ways. But I believe him when he says he's found a way to make it work there too.

He runs into the real problems, though, when he adds quantum mechanics to the mix. Here, the reasoning became hard to follow, but, as I understand him, it goes something like this. The normal (time-dependent) Schrödinger Equation makes integral reference to time, which it sharply distinguishes from space. This clashes violently with General Relativity, which views them both as parts of the same thing, and, despite repeated attempts, no one can figure out how to pull apart the four dimensions of General Relativity into three space-like ones and one time-like one in a way that will mesh with the Schrödinger Equation.

Barbour says that's because it can't be done. Instead, he makes the radical suggestion that the Universe's structure is better modeled by a version of the time-independent Schrödinger Equation, which describes static solutions to the normal Schrödinger Equation. These static solutions are the "Nows", the instants of time. The motivation is not implausible: as another reviewer points out, the time-independent Schrödinger Equation is supposed to be appropriate in situations where energy is constant and there are no external inputs. Those conditions evidently apply to the whole Universe. It's very hard to know whether to believe the argument. Your first response is that it has to be a technical trick. However, as Barbour points out, there are many examples in physics where things which at first looked like technical tricks turned out to be deep insights, and it's often best to trust the math and see where it goes.

So the Universe is technically static, and consists of a gigantic collection of "Nows". Motion is an illusion; it springs from the fact that the "Nows" are related to each other, and, crucially, that there is a tendency for them to contain "time-capsules", by which he means structures which look like records of past events; as he says, we only believe in the past because we have memories and other records of it. He illustrates using a nice example with a charged particle moving through a cloud chamber, where the track of water droplets is the time-capsule. He also compares with Leibniz's philosophy; in Leibniz's terms, the "Nows" are, roughly, monads, and there is pre-established harmony between them due to the fact that they are all solutions to the same equation.

As the book progresses, it becomes more and more mystical and Yoda-like. I had real trouble believing the final sections, which to me came across as the purest hand-waving and poeticising. In particular, he admits himself that he doesn't have a clear explanation of why the "Nows" containing "time-capsules" should tend to get high probabilities, something that is essential to the theory. But there's no doubt that he's asking interesting and original questions, and I'm certainly not competent to judge whether the answers make sense. Maybe he's right, and "time" is just one of those approximations which hold in our everyday world where quantum and relativity effects can safely be ignored, but break down in more extreme situations. If you want to read a really unusual physics book which takes the fundamental issues seriously, you might want to check this one out.

Barry Cunningham

Rating: really liked it
A fabulous book that really made me think about previously accepted concepts - everyone interested in this sort of science should read this book, they will be glad they did!

Rob

Rating: really liked it
if you love Roger Penrose and Lee Smolin, and REALLY UNDERSTAND WHAT THEY ARE TALKING ABOUT, you might like this book. basically, the paradoxical incongruity between quantum theory and general relativity is attacked once more. i was blown away. the strongest argument, for me, that time does not really exist was this: if you look at any ISOLATED quantum system with CONSTANT ENERGY, you will expect it to be in a STATIONARY STATE. think of any isolated atom, with all its electrons sitting in orbitals. you will always use the time-INDEPENDENT schrodinger equation to find the possible states. time will simply not enter into the problem. BUT THIS IS EXACTLY THE SITUATION WITH THE WAVEFUNCTION FOR THE ENTIRE UNIVERSE. constant energy? check. no interaction with 'something else'? check. ergo, the wavefunction of the entire universe should not contain time. it doesn't evolve! holy crap!

he talks a lot about Machian mechanics and tries to explain how and why we might have the mistaken (extremely convincing) impression that time does, in fact, pass. i will definitely be going out and reading every word by Julian Barbour i can get my hands on.

the funny (not ha ha funny) thing is that even though this was an AMAZING book, i'm not at all surprised that it has a horrible rating both here and over at amazon. Barbour seems to have tried to make his book accessible to the "educated layman", but people who don't have a degree in physics will probably find this book to be totally impenetrable. and frankly, i wish he hadn't tried. his thesis is both astounding and very well-supported (that the passage of time is an illusion), but it is based on some extremely advanced principles. yet he has tried to lay it out without a single equation. NO MATH! instead of talking about the real and imaginary components of complex wavefunctions and the corresponding probability amplitude, he introduces the analogy of a 'red mist', 'green mist', and 'blue mist' which pervade space. he waxes poetic at every turn, bringing in soaring lines from shakespeare and keats and many others, as well as spinning some purple prose of his own, in order to broaden the appeal of the book.

unfortunately, this alternates with arguments that i think simply cannot mean much if you don't have a very good grasp of both QM and relativity. it was a five-star book for me, but yeah, not for you, most likely.

Robert

Rating: really liked it
I got interested in this book after attending a seminar given by Barbour at the University of New Brunswick.

THIS REVIEW HAS BEEN CURTAILED IN PROTEST AT GOODREADS' CENSORSHIP POLICY

See the complete review here:

http://arbieroo.booklikes.com/post/66...

Bria

Rating: really liked it
I strongly suspect the main problem is that I was too stupid and distractable to do a good job reading this, but as far as I could glean:

This book contains, in order of most pages devoted to the least:
-Holding the reader's hand and reassuring them that it's not too hard to understand it
-Referring to what will be explained and made much clear later in the book
-Repeating or rephrasing minor points or peripheral frameworks in order to make the ideas easier to picture
-Brief summaries of or mere references to concepts in physics
-Bafflingly irrelevant personal stories
-Lamenting the state of the system that won't accept the ideas of outsides because they are too wedded to the status quo
-Actual substance on how time might not exist

Okay, the actual substance could probably be moved up two or three slots, but if you take into account that the vast majority of it is just reiteration, it's still down pretty low. I know that there is legitimacy to the claim that being inside the system that defines the status quo can make people more reluctant to accept different or difficult ideas, but that is not evidence either way for whether that different or difficult idea is true. And maybe it does make sense to sort of pepper the entire human landscape with your ideas by presenting them to public. I just don't know if writing this pop science book really helped. I've noticed this problem, where a scientist tries to educate non-scientists by writing a book, because that is the best way to get to the public, except that the book just goes on and on and could have been much clearer and more effective if it had been concise, like an article. Is it that people won't buy a pop science book if it's too short? I mean, if you're going to take out absolutely all of the actual science and dumb it down for the public to read, why make them read 300 pages if there's not that much information left? I would have gladly read an entire book on the subject, if the entire book had been illuminating and explanatory.

Wren

Rating: really liked it
This is absolutely one of my favourite science books. I picked it up initially because the premise fascinated me. The nonexistence (as an objective reality, mind you) of time was something I've always sort of intuited, and to see physics exploring the same conclusions immediately sparked my interest. Ironically, though, that is not the strongest part of this book.

I think any good science book should not only explain to you a theory and its application, but give you the context as well. A good science book will teach you why the idea it presents is important, what its impact might be if true, and most importantly it will teach you anything you need to know about the subject (in this case, Physics) to understand the idea, from the ground up. And a good science book will do this without dumbing things down.

This is a good science book, for all those reasons and more. In fact, this book taught me much of what I know about theoretical physics.

Barbour's history as a science historian also shows, as he explores not only the idea but his personal story of how he began to come to these conclusions and his quest to find a way to test them.

At its heart, this book espouses a whole philosophy about the universe, and a revolutionary one at that. It is a counter argument to both string theory and western religion. It is one of the most fascinating things you will ever read, if you have the tenacity to make it through to the end.

But the best thing about this book is that it understands its own ideas may not be true, and in fact (in the great tradition of science) probably aren't. And it goes on to tell us that this is okay, because that is how science works, and because these are things we need to be exploring anyway.

This book will teach you physics, challenge your philosophy, and leave you with a new appreciation for science and the universe. Barbour is a credit to the world.

P.S. During the reading of this book was the first and probably only time in my life when I have ever uttered the phrase "aww, poor quantum wave packets!"

Erik

Rating: really liked it
Julian Barbour is the foremost representative of the Machian view of physics, epitomized by the idea that time disappears on the cosmological view replaced by the comparison of changes with changes within time. There is no time for the universe itself. Turns out he can defend that view with a timeless view of both GTR and of QM by way of the stationary state DeWitt-Wheeler equation. He also has an explanation of why there seems to be time in terms of traces and time-capsules which result from quantum measurements or branching depending on your view. I'm sympathetic to Barbour, but if you were not, he doesn't do a very good job of discussing alternatives and a crucial issue, the relativity of rotation does not get mentioned. He just formulates GTR in a timeless relational framework and I guess the physical invariance or relativity of rotating reference frames you are supposed to get out of that. I didn't see that however, nor did I see a mechanism for the exchange of inertia and gravitation in different rotating frames. I did see an interesting explanation of inertial or force-free frames as islands within a dynamical universe, and the so-called un-Machian solutions of GTR would then be interpreted as such islands seemingly free of force, but really just special cases of a dynamics of matter, space and force.

Richard Thompson

Rating: really liked it
My math stops at second year college calculus and linear algebra, with a smattering of group theory, and I never took a college level physics course, though I have read a lot of popular books on physics, including several that push my math to its edge and bit beyond, so I am not qualified to judge Barbour in a rigorous way. But I have long been fascinated by the theory of the pre-Socratic philosopher Parmenides that motion and time are illusions, so I was immediately drawn to the idea of a serious theory of physics based on the idea that tine does not exist. And I believe that this kind of daring out of the box thinking that questions such a fundamental concept as time is more likely to be the basis for the next great strides in physics than more and more diddling with non-falsifiable string theory.

Barbour doesn't completely do away with anything resembling time. He sees the universe that we perceive as a pathway through an infinite number of static instances of reality which each contain a record of other instances along the path that we perceive as time. Maybe. I don't know. In the end it didn't appeal to me. I saw how his concept could simplify and solve some difficult points in other theories, but I felt that his construction of the pathway through instances was a little strained, as was his idea that all of the instances that we inhabit must be "time capsules" with built in histories that we perceive as the past. From my position of relative ignorance, it seems more likely that time does exist and that it is an expression of entropy and incomplete information as advocated by Carlo Rovelli in The Order of Time.

I also found Barbour's effort at writing a popular science book for a broad audience to be less than it might have been. It was both too complicated and too simple. He stays completely away from math, but his attempts to provide simplified non-mathematical explanations were not as good as top quality popular science writers like Stephen Hawking and Murray Gell-Mann. I found I had to reread his simplified explanations to understand them, when I would have been able to instantly grasp the same points if he had been a better writer or if he had favored us with a few equations.

Nevertheless, my hat is off to anyone willing to challenge time and to do his physics on a farm giving up an academic career that would have been frustrated by his dedication to a cool theory that sits so far outside of the mainstream.

Nicholas

Rating: really liked it
I was too far into this before it became a chore, and feeling unable to rescind the investment I'd made, I ploughed on.The problem for me was mainly one of clarity and lack of allegorical description when dealing with complex theories, which I felt should have been present in a work aimed at a lay readership a part of which I presumed myself to be. There seemed to be a lack in the consistency of the intellectual level of to whom the book is addressed. On the one hand you are reminded of Pythagoras's theorem and the Two Slit experiment and on the other you are asked to perform arduous visualisations to grasp interconnections of theoretical particles in multiple dimensions.
A greater part of the book is dedicated to the retreading of Relativity theory, Quantum theory, Mach's Principle and Schrodinger's equations, which I guess would be familiar to most readers who get past the notes on the back cover and are covered far more lucidly by other popular authors. It is then shown how the established theories can still remain relevant within the authors newer conceptual framework of a Timeless Configuration Space, where our experiences are constructed by the action of Probability Waves on Time Capsules under the influence of Psychophysical Parallelism.
Although I comprehended most of it in a "general way", I felt that the author, who works independently of the scientific community, was aiming primarily at academic recognition through a rigorous and credible exposition of his theory, which was won at the expense of clarity to the general reader.

Cassandra Kay Silva

Rating: really liked it
I mean the idea behind the book was really good. I was excited to read about a whole new way to excuse ourselves from this time like track forward we seem to find ourselves in. Some of the backing seemed pretty sound from my grasp of these issues. The problem is, I was left with kind of giant question mark at the end? The conclusion was frankly so poorly written that I found myself re reading the original entry chapters to kind of tie MYSELF back to the context since the author didn't do it for me. Perhaps everyone does not need this kind of hand holding but frankly I was a bit lost. It wasn't a boring book though and I think he made a lot of interesting points, although I when it got the the latter half even I found it started to meander and the backing seemed to get thinner and thinner for the ideas he was trying to present. I think that's why this book really could have used a better ending. Just to really tie all these loose ends together and give some kind of final shabang to the whole Ending of time as it were.

Sebastian

Rating: really liked it
In an unnerving moment of synchronicity, as I battled through the muddy trenches of page 299 of this fascinating book, scrunched up in the mottled shade of a pine forest on the painfully idyllic island of Mljet, a kingfisher landed on a nearby branch. At least I think it was a kingfisher – a relatively small bird with a bright blue “cape”, it tweeted a few times, loudly, as if demanding that I pay attention to it, and then flittered away.

“This means something”, I thought to myself, echoing Close Encounters, and then promptly shook off the feeling and went back to feeling inadequate, i.e. reading the book.

I have gotten to a gnarly point where I know enough about physics to wrestle with some very deep, foundational issues, such as Mach’s principle that forms part of the core of this book, and yet I do not know enough physics to grapple with these issues on a direct equations-on-blackboard manner. This leads to mental jiu-jitsu with books such as Barbour’s, written neither for a complete layman, who would, I suspect, quickly become mired in its technical (and philosophical) arguments, yet neither for an expert who would find his “red and blue mist stand for parts of a complex function” allegories annoying and distracting (as I did, knowing a bit of the “ole quannum”).

The idea of the book, that time is an illusion generated by a non-temporal best-match sequencing of 3d “frames” in an all-encompassing configuration space, generally seems solid as an idea, but I have no, heh, idea if the evidence is solid, or if the conjectures are in any way realistic – each part of the book started off very clear, then grew difficult, but understandable, and then slowly, at about the 80% mark, became incomprehensibly complex.

What I definitely did get out of the book and am very grateful for is the hammering-home of the idea of configuration spaces, and the way they are utilized in physical analyses – Barbour returns to this concept over and over, and emphasizes it particularly in relation to the Schrödinger equation in a way it was not emphasized in anything I’ve read before, providing a few eye-opening fringe benefits to reading this work.

I suspect, however, that this is a book I will return to once I’ve packed a few more tensors under the belt.

Jonathan Hockey

Rating: really liked it
I don't fundamentally agree with this notion of timelessness. I think, if anything what is shown is that the present is pregnant with the structure of its potential future and the memory of its past, and that we are in a perpetual state of becoming in the present, guided by all this structure. With that proviso in mind, I find a lot to agree with and to ponder in this book. A unique perspective and insight on some deep and current problems in theoretical physics. No conforming with standard approaches, he gives his own specific reasons for the views that he holds, although they may often be quite complicated. On that, I would criticise slightly the expression at times of the ideas seems a bit clunky and repetitive of certain points. Still, if you want an honest assessment of where theoretical physics is and where it may potentially be in the future, then this is a good book to go for and will not insult your intelligence like many of the popular science books around that are only interested these days in promoting over simplified narratives for people to conform to on authority and require little deep thought or introspection but give you merely a few gimmicky gotcha style points to attack "non-Scientists" with, with little interest in truth, reality and being reasonable. I point this out here, because I would say I have some bitterness at wasting some years of my life in the past, taking various popular science books to be a genuine and sincere search for the truth of something, when they have become just an industry for giving people comforting lies to stop thought. Julian Barbour is in that rare breed that is free of that industrialised mass produced form of popular science, along with the likes of Roger Penrose and Lee Smolin.

Pvw

Rating: really liked it
I have since long been open to the idea that time is only an illusion, a static extension in a complex multi-dimensional form. Barbour's book does no good job in promoting that idea, even though it wants to. All his babble about Platonia (Barbour's name for the static multiverse) and the existence of 'time capsules' (micro-sized qualities of atoms that allow observers to distinguish between past and future), is too far-fetched. Instead of opening readers' eyes to the possibility that all events past, present and future may actually co-exist in a higher dimensional shape, Barbour estranges the reader from it by elaborating on his terribly complex but unconvincing world view that no sentient being could go along with.

Jerry

Rating: really liked it
Not very convincing. Argument is that space-time doesn’t exist. It is an illusion. Like the sun seeming to orbit the earth. States of the universe exist and seem to order themselves in a temporal sequence. Life may really be more like an event simulation than like a continuous simulation. States move from one quantum state to another quantum state in a quantum “time”. States of existence may be probabilistic (like quantum physics) where the uncertainty is not in knowing what state the system is in but in fact the system is in more than one state simultaneously and one state is detected only in the process of observation (like Schrodinger’s cat, both dead & alive). Many-worlds interpretation: more than one world exists but we are only aware of one world.