Brian Greene's previous books are exemplars of what science writing should be: clear, wide-ranging in discussion and respectful of the intelligence of his audience. The Elegant Universe and The Fabric of the Cosmos are two of my three favorite popular science books. The third, Kip Thorne's Black Holes and Time Warps, is another superb example of science writing at its best. Now Brian Greene has added another masterpiece to the list. Everything that distinguishes Greene's writing style is in evidence in The Hidden Reality. His elegant prose is enjoyable to read. His brilliant ability to explain difficult abstract ideas in everyday language using easily understood examples still amazes me. And his use of vivid word pictures that always seem perfectly matched to the topic he's discussing propels his narrative forward so that the reader is never bored.
Yes The Hidden Reality is more accessible than his previous books. This book seems easier to read and is readily understandable. In his earlier books, I often read a paragraph several times in order to fully comprehend what Greene was attempting to communicate. That is something science and math majors are used to doing when reading textbooks but difficult for those not as scientifically adept. Greene's first two books dealt with Quantum Mechanics, String Theory and Einstein's Special and General Theories of Relativity: vast math-intensive topics that he was able to distill masterfully. The Hidden Reality inhabits a more abstract world, a conceptually challenging world. I quickly found Greene's more casual approach extremely helpful, even comforting, when I felt slightly adrift. The topics he discusses begin with the geometry of the universe: whether it is spherical (or positively curved), flat (with zero curvature) like a tabletop, or negatively curved like a Pringle.
The book devotes considerable time to the critical question of whether the universe is finite or infinite in size, something which has profound scientific and philosophical implications. It is a statistical certainty that in an infinite universe, regions of local space like ours will be endlessly repeated. In other words, assuming an infinite spatial universe with an expanding big-bang beginning, there are only a finite number of possible matter and energy configurations because the amount of energy and matter is finite. But there is an infinite amount of space within which those configurations will play out. Greene uses the example of a friend named Imelda whose passion for clothing has her purchasing 1000 pairs of shoes and 500 dresses. If Imelda is blessed with an infinitely long lifespan then, despite her vast wardrobe, if she changes outfits daily, within 1400 years she will have exhausted all possible new combinations. Imelda will be forced to repeat her sartorial choices. Philosophically, of course, all of that repetition of stars, planets and life's building blocks suggests that there are an infinite number of doppelgangers of each and every one of us. These infinite duplicates of ourselves would inhabit similar worlds that are forever hidden from mutual observation because the speed of light is finite. As Einstein showed in his Special Theory of Relativity, light-speed (300,000 km/sec) is the fastest rate by which information can be communicated. The bottom line: in an infinite universe the overwhelming bulk of reality remains hidden from its inhabitants by vast distances or by parallel dimensions harboring realities of every possible configuration.
In a finite spherical universe, on the other hand, the light from distant objects should ultimately traverse it several times, leading to multiple images of galaxies, for example. This hasn't been observed as yet, suggesting that the universe is either finite but huge or actually infinite in size. Though the size and shape of the universe remain undetermined, scientists when cornered tend to believe its size is infinite. Recent data also suggests that the universe is flat like a tabletop in shape.
Greene discusses all of the current hot topics in cosmology: brane-worlds, the multiverse, the holographic universe, unseen parallel worlds in dimensions separated by millimeters, our universe as a super-advanced computer program, the essentially hidden nature of reality. These are topics that have been discussed in other books but seldom with the passion for communication and clarity of thought that Greene exhibits in this one. The topics here are abstract concepts that exist at the very boundaries of human thought but Greene somehow manages to bring them down to earth. Even if you don't understand everything, the scientific vistas that Greene offers in this superb book are breathtaking in their intellectual beauty. You will find your personal horizons exponentially expanded. The Hidden Reality is replete with excellent illustrations that illuminate the material and are fun to look at. If this kind of science intrigues you then you will love this book. Brian Greene has written another masterpiece in a difficult genre.
Beginning in the 16th Century, physics started to change from a purely scholastic mode of inquiry, in which questions were answered by argument from first principles and ancient authority, into a scientific one, in which observation and mathematical law predominated. With the introduction of Newton's work and his (and Leibniz') invention of the calculus, physics became a modern science, in which mathematics played a key role not only in testing theories, but in predicting phenomena as well. Even so, it was still possible for the non-scientist to understand much of the work of physicists, as it still dealt (for the most part) with laws and phenomena that could be observed, experienced, or at least imagined with the average person.
With the advent of relativity and quantum mechanics in the early 20th century, this all changed. Special Relativity dealt with velocities far beyond that which any human could ever experience. General Relativity dealt with interactions on a cosmic scale. And quantum mechanics dealt with scales far smaller than that which could be experienced or observed- even by physicists. What these new disciplines shared was that they they could only be truly understood by someone conversant with the mathematics involved. Although mass-induced curvature of space (for example) is commonly explained by analogy to a weight on a rubber sheet; that's at best, a weak metaphor. A ball bearing rolling on a rubber sheet is still being pulled down by gravity; it is not tracing a path in curved space that minimizes action.
As modern theories physics have become more complex, more purely mathematical, and further removed from the experience of the perceivable world, the books that attempt to explain things like inflationary cosmologies, string theory and supersymmetry have become increasingly less satisfying. And that brings us to the central failure of almost every popular book on modern physics I've ever read- the inability to actually explain the why and how. After reading countless books by popular authors like Tim Ferris, I realized that although many were, indeed, excellent writers, none of them actually understood the physics they were purporting to explain. At beast, they were simply repeating the metaphors they'd been given. They didn't understand the physics well enough to explain it.
There were a few exceptions- popular books written by actual physicists who also had a particular gift for teaching and explanation. To date, I've only found three who both have a deep understanding of modern physics, and who can convey more than a metaphorical understanding of this to a reasonably intelligent, but non-specialist, reader: Richard Feynman, Alan Guth, and Brian Greene. True, there are other physicists who write popular books, but most aim pretty low. They're satisfied to give a general sort of metaphorical explanation- curved space is like a curved rubber sheet, expansion is like inflating a beach ball, and strings are like... little strings. But Feynman, Guth and Greene each tried to really convey the real science.
The late Richard Feynman is still the master. His lectures- especially "The Character of Physical Law"- did a magnificent job of making clear even such difficult concepts as the quantum explanation of diffraction. Guth's "The Inflationary Universe" does a superb job of explaining topics like tension and negative energy in telling his story of the origins of cosmic inflation theory. And Brian Greene, author of the current volume under discussion, has now produced his third book attempting to explain some very difficult ideas to the lay reader. In "The Hidden Reality", Green tackles string theory, the multiverse, symmetry, group theory, and dozens of other topics, and he does so without resort to any "it's just like..." metaphors. He uses graphic representations when possible, to illustrate mathematical relationships without math when possible (although much of the real math can be found in the appendix.) He explains where and how contemporary cosmological theories originated, and gives the reader a good sense of exactly how we arrived at a position in which physics is largely dominated by untestable theories that make few predictions about the measurable universe- and why this is not necessarily a problem.
Greene is one of the principle authors of modern string theory, and he does a superlative job of conveying, for the lay reader, both the state of string theory, and its genesis. While to fully understand such notions as (say) the role of Calabi-Yu shapes in defining the topology of the multidimensional universe would no doubt require a real familiarity of topology, I think Greene comes as close as possible (or at least as close as I've seen) in conveying to the reader why it is that these shapes play a role in defining space, and how it is that physicists came to propose their existence. His explanation of quantum uncertainly and of Schrodinger's probability wave is probably the best non-mathematical one I've read.
This is not an easy book to read. I went as far as a few calculus courses and a semester of physics back in my undergraduate days, and I found this book fairly hard going. It's not terribly mathematical (except in the appendices) but the concepts are not easy, and there's little if any fluff to be found. This is not the sort of breezy reading found in the typical popular physics book (here's the atom, here's a quark, wasn't that cool?) The reader who attempts to simply skim through without trying to follow Greene's narration and really understand what he's trying to explain will quickly find themselves lost, reading words without a clue of what they mean. I've been reading it for two weeks, attacking a chapter (or part of a chapter) each day, and often backtracking to make sure I understand what Greene is trying to convey. The reader who is prepared to take this approach, and spend a lot of time reading, pausing, think about what they've read, and rereading each section to make sure they really understand what's going on, will find this a very rewarding book.
Let me say from the get go, I am a huge Brian Greene fan, having read both his previous books and having found them deeply edifying. Few writers working today possess his ability to take complex material and explain it in ways that the interested layman can digest. When I learned of his new book, I was excited to dive-in.
Unfortunately, for reasons that are not entirely clear to me, "The Hidden Reality" is far more opaque than his previous books. Time and again I found myself rereading a particular section, unable to decipher what he was seeking to explain. This may result from my own short-comings, I suspect that they might just as well arise from those limitations that Greene, from the very beginning, admits bedevils the notion of the "multiverse." Even more so than in String Theory, this topic currently stands at a point of being little more than speculation. Yes, the math creates the possibility that these other realms exist, but no one has to date suggested a method of falsification for this theory, nor does it offer much in the way of testable predictions.
Sometimes when he tries to counter critics, Green proves to be his own worst enemy. Consider a chapter where he argues against those who point out the difficulty of testing the hypothesis of a "muliverse." In reply, Greene points to Einstein's theories and the inability to demonstrate their veracity through experimentation in the early 20th century when they first appeared. However, this ignores the fact that Einstein's theories offered obvious precise predictions that, even if not testable at the time, one could imagine appearing in the near future. Had these predictions not withstood tests, out would have gone the theory. To date, nobody can offer similar predictions through this theory that we are likely to be able to test anytime soon.
The result of these weaknesses is that I found myself often lost in the weeds, left with little more than the point that the math says that these things may be so. I can understand Greene's enthusiasm at the possibility of limitless realities beyond our own, but glorying at the possibility doesn't get me any closer to accepting -- or even understanding -- that these intriguing suggestions might prove real.
If you are a Brian Greene fan, then you may have read his previous books The Elegant Universe and the Fabric of the Cosmos, both of which are beautiful reads. In this his latest book, he lends his understanding of the most advanced concepts in physics and astrophysics to bring us into a world that scientists believe exist mathematically, but so far have not been able to substantiate with physical evidence. This book involves a whole slew of scientific disciplines that under normal conditions would be daunting to try to understand. They include:
* String Theory
* Subatomic particles
* Quantum physics
* Parallel worlds
* The Inflationary Universe
* Cyclic Multiverses
Perhaps you have experienced the same problem I have through the years. So many science writers want to impress you with how smart THEY are. They do this by introducing complex terms which I refer to as jargon. They give you mathematics which at one point years ago, you may have understood, but now you have no chance. In this book the author has planned it out thoroughly for the reader. He does this by introducing a topic at the beginning of the chapter, and telling you just what you need to know by way of background. He assumes no mathematical training on behalf of the reader, and teaches by metaphor, and analogy. He does not go off on tangents into areas that are both confusing and complicated. If he feels you need to know much more than what he has given as a preliminary background, he has relegated it to the notes in the back of the book. This is a kind author, and is one of the reasons why his works have sold so well through the years.
Just take a look at a couple of the very intriguing concepts that Greene expands upon in this book:
* Is there more than one universe? If so where are these parallel worlds? Could they be right next to us and we do not realize it because we cannot see them?
* Are they out there at the edge of the known universe?
* What about the concept of multiple universes? They are also known as parallel worlds, multiple universes, alternate universes, or the metaverse, multiverse, and megaverse.
* Depending upon the mathematics you use, we are getting some strange results indicating that what we believe we see is not what is actually going on. Thus the natural, intuitive understanding developed by Einstein did not follow though in Quantum Mechanics. When Quantum Mechanics clearly demonstrated that the scientific predictions are at best probabilistic as opposed to certain, it was earthshaking.
* The mathematics in vogue today is completely at odds with the single definite reality we all see? We're in trouble.
* It now turns out that Einstein when he created the concept of the mathematical constant may in the end be proven right.
There are 322 pages of narrative in this book followed by 30 pages of notes, and then several pages of suggested readings. I think you will love this book. This is an adventure for the reader as the author whisks us along on a journey of the outer limits of our knowledge of the universe. It is completely readable even to the novice science reader. No math required just a fertile imagination and the desired to be entertained intellectually while absorbing a world of wildly interesting information. Good luck, and thank you for reading this review.
Richard C. Stoyeck
on March 26, 2011
I am writing this review from the perspective of a person who has some rudimentary knowledge of classical physics, relativity, quantum mechanics and cosmology (and so on). That is I read a lot of books by Physicists who try to make the subject comprehensible. This means that I cannot comment on the accuracy of the physics described in the book or how it might help physicists further understand the subject. On the other hand, if Greene's intention was to write a book that would get readers thinking about the concept of reality, then I think he has succeeded brilliantly. Essentially, he has taken the top end of speculative physics and, in a number of cases, stretched the level of speculation a notch or two. His thinking about the need to do this is sound; unless scientists (and others?) are willing to stretch their thinking into new zones of possibility, progress will not leave our current reality. Once reality was that the universe (whatever that was) revolved around the Earth - the stretch in thinking to view reality in any other way must have been amazing. In a sense, Greene is not asking for anything more than a similar "wrench" in our thinking. So my recommendation is, don't worry too much about the physics, read the book and enjoy the ride.
Dunedin, New Zealand
on May 16, 2011
Brian Greene is truly an excellent science writer. Though there are many ideas that cant be communicated to the lay reader and specifics almost never can, Brian Greene manages to illustrate the general ideas behind what many physicists are thinking and working on and why. The Hidden Reality is an overview of where modern day physics has taken us in terms of the potential nature of reality. In particular he explores the potential initial configurations of the universe and as well the subsequent potential mechanics and what these potentials mean for the nature of reality. He also discusses the nature of reality from the perspective of general relativity, string theory and quantum mechanics. I realize this is vague, but its hard to give a specific overview of what is talked about as the author is almost as concise as he can be to convey the ideas he attempts to. Nonetheless i'll give it a try.
The book starts out with the first example of how if we consider our planet and current aggregate configuration and history as unique, then the law of large numbers might cause some alarm in an infinite universe. In particular if we do thought experiment of assuming the universe is truly infinite (spatially with matter in all regions) then it implies that there must be copies of us out there. This results can be deduced from several vantage points and in the book, it is the fact that any negligbly small probability will be hit an infinite number of times if we have an infinite number of experiments. Though the "initial conditions" presented are just a hypothesis, this first chapter sets an eerie start which the book continues to build momentum on. The author then discusses inflationary universes and how they too give rise to multiverse scenarios in which parallel universes will remain unseen as they have inflated at distances that will never be reached. He also discusses what seem to be paradoxes of differing views of infinity, for example, those inside an expanding universe will consider it infinite space with finite time whereas outside they will consider it finite space with infinite time. One gets a glimpse of some of physicists insights but the ideas can be tough and i think to truly understand much of it deeply requires studying the math. The author then gives a brief outline of string theory and gets into the potential multiverse of branes that we might live in (i wont bother to try to paraphrase this part). Subsequent to this the author then introduces what I thought was the first model for parallel universes which is the quantum multiverse in which there is no collapse of the wave function and all possibilities are realized and the wave patterns we see are the parallel worlds interfering. The history of this is given as well as the philosophical misgivings of many scientists. The author then gets into the holographic universe which is pretty hard to grasp, (im pretty sure its hard to grasp even for the expert!) in which our sensations might all be a product of what happens on a lower dimensional space as there is a mathematical mapping between information of a surface with its higher dimensional body. This evolved from some blackhole information theory result... Clearly the book discusses things which are pretty out there but does a good job in trying to communicate what can be communicated to the reader. The book then ventures further into philosophy rather than science and discusses some ideas about what is the "reality" of a computed world and what is the "reality" that mathematical equations exist in.
Intertwined throughout the book is the authors discussion of what is science. How much of these interesting ideas about the universe is science rather than philosophy. Much theoretical physics, in particular string theory, has come under a lot of pressure for producing no real testable experiments to its validity (though the experiments being thought up are getting closer to testable) and the author discusses his ideas as to what is legitimate and what is not. The book is primarily on various multiverse possibilities for the universe and how basically all modern theories have multiverse interpretations. Embedded in the writing is also the authors philosophy to legitimize his views on science - he includes some fairly out there theories of computational universes (ie extraordinarily complex simlife type computations) and the multiverse of logically correct statements and equations to show where he draws the line. I pretty much think this is a 5 star book but it is not always consistent. For example, infinity is a complicated issue as there are levels of infinity, integers are countably infinite, the real line is not. In his first chapter, the author argues as to why a multiverse will have a copy of us, he invokes quantum mechanics to legitimize the discreteness of space and thus uses a limiting exercise in the countable sense to get to the conclusion. In the last chapter though he questions this implicitly (but doesnt discuss how it affects his previous arguments) by using the continuum of schrodingers equations values to say we cant escape an infinite configuration space. This is obviously subtle and in aggregate this is a very interesting read in which complicated arguments and phenomenon are well described and the nature of reality and ideas are tackled. I learned a lot and I think everyone can get something out of it.
on February 1, 2011
First a disclaimer: Brian Greene is my favorite writer of layman's books on cosmology and theoretical physics. I have enjoyed all three of his books. I consider myself an interested lay person with no formal education in physics or mathematics beyond high school. Greene writes in a clean and easily understood manner and has a gift for using everyday analogies or pictures to describe difficult concepts. I should add that he usually includes more detailed and mathematical explanations in the end notes. Even if you don't get the math (as I don't) these end notes can add a lot to the text.
Green explores all the various types of parallel universe that have emerged from cosmological, quantum and string theory with each type getting is own chapter or chapters of explanation. My dilemma with this book is that it's value really depends on whether you already know something about cosmology and parallel universes or whether you are coming at this cold. While Greene's writing is excellent as always, the book does not really break new ground, mainly because there isn't much new ground to be broken in the absence of major advances in theory or experimental evidence in the last few years. So if you have read other works in this area in recent years including Michio Kaku, Lisa Randall, Alexander Vilenkin or even Greene's previous book, I don't think you will find much that is new here and so only three stars. Nonetheless, as a lay reader I find the concepts of cosmology slippery and difficult to grasp and so Greene's lucid explanations always help even if I have read similar works in the last couple of years. However, if this is your first foray into cosmology then this is a great starting point for you and is worthy of five stars.
I'm absolutely fascinated by the idea that there are potentially other universes out there, perhaps even containing a copy of myself in them. I mean you just can't make this stuff up!
I am very intrigued by the new theories in science. Although I have an advanced degree, I am not by any means a math/science type of person. I was hoping with this book to understand better the ideas of parallel universes, string theory, multiverses, etc. This book didn't do it for me.
The text, even though the author claims is dumbed it down, was difficult to understand. I suspect someone who has more of a physics background will be better able to assimilate the information. Still, there is one thing I do understand. If these theories are even close to the truth we are in for a whole new way of viewing our existence. Some people still have a hard time with evolution, wait until they get hold of this stuff!
The concepts are fascinating, exhilarating, and will make humans question everything about what we perceive is reality.
The Hidden Reality speaks not only of the Universe and possible Universes but also has other scientists and physicists opinions and theories on Universes and Multiverses. It delves into parallel worlds and doppelgangers, particles, string theory, cosmology, holograms, black holes and talks about whether the Universe is infinite or finite.
The question is, what won't you learn from this book?- After reading this book you will walk away a lot more enlightened in general. I learned a ton of info just reading the first 30 pages and afterwards had a discussion with someone who had a question regarding The Universe, they thought I was an expert.. And this is just from the knowledge I learned on the first 30 pages.
If you read this book you'll feel like an expert in quantum mechanics, quantum physics, science and relativity by the time you're done reading this. If not that, you'll be more informed on the subjects.
Brian Greene has an unbiased yet curious passion for finding out the truth about reality while still remaining objective and giving it to the reader in an interesting and entertaining way using analogies and comparisons.
If you have a very open mind and want to read about these different scientific theories you will enjoy it. He explores nearly every possibility... scientific possibility for existence and every possible Universe theory imaginable. Also contains pictures, some very interesting ones regarding his points.
For the most part, the whole book is good. Especially the beginning or first 50 pages, and also the end where he starts a little philosophizing about things and talking of computers and their role in our reality.
The bottom line is this guy knows his stuff... If you are into this subject matter or can handle reading this then i'd recommend it.
It's a book about revealing the true nature of reality and our existence and role in the Universe- How could I not give it 5 stars? He covered it all and did it well.
on March 10, 2011
Bruce Schumm: Deep Down Things: The Breathtaking Beauty of Particle Physics, Peter Woit: Not Even Wrong: The Failure of String Theory and the Search for Unity in Physical Law, Lee Smolin: The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next
Brian Greene is, by all accounts, one of the most gifted theoretical physicists and writers around, particularly on string theory. His earlier book on string theory, The Elegant Universe, is spellbinding, and reading it along with Roger Penrose's books on cosmology and Stephen Hawking's earlier books, you can get pretty well grounded on the state of post-relativistic physics and cosmology as it is currently accepted by the majority of the academic physics community.
That is just the problem. None of string theory may be true at all. There has been no experimental verification of any of the elements of mathematically based string theory after 30 years or so of work, and, in fact, the theory may not even be "falsifiable." That is, it appears not to be subject to the rigors of the experimental scientific method, although the string theorists hope that with higher energy colliders and the like it may, someday, be testable.
Heresy, you say! Yes, that is probably the correct word for it, since string theory, and derivatively, theories of multi-dimensions and multi-universes, have become the mainstay, the sine qua non, of the academic particle physics and cosmology community. It has even become, in a sense, politically incorrect to speak out against string theory. A young physics graduate student who rejects or even seriously questions this "theory of everything" may have major problems in finding an academic job in an already crowded field, especially in the U.S. Established physicists who have devoted their lives to string theory would be left out in the cold if this theory were ever to be discarded for lack of any experimental evidence to prove it correct, incorrect, or even just partially correct. It has, therefore, many of the attributes generally given to a religion or belief system that lacks any scientifically verifiable substrate. It could all be true, of course, but we may never know, one way or the other.
I suggest to potential readers of Greene's latest book, especially those without much background in physics or particle theory, that they start by reading the books listed at the top of this review, all written by recognized mathematicians and physicists in the field. The first, by Schumm, gives a solid grounding in the Standard Model of experimentally proven particle physics, with which no one, including string theorists, disagrees. (String theory is at one level an attempt to explain and refine the Standard Model.) Shumm's book is tough going, but by the time you have finished you will have a pretty good general idea of what the Standard Model is all about, including the complex "spaces" inhabited by the various particles like quarks, muons, etc. The second book, by Woit, assumes you already have some basic understanding of the Standard Model, and takes you through the development and (now) long history of string theory, including the "religious" and academic political aspects of it described in the 3rd text paragraph of this review. Woit pretty successfully debunks string theory, in my layman's opinion. He maintains an ongoing website based on the book (search "not even wrong") in which there are continuing posts by various string theorists trying to refute Woit's assertions, followed by clear and convincing responses by Woit. The third book, by Smolin, is less technical and more accessible, but makes the whole point quite well, if you want to get to the heart of the matter quickly. (Greene does not address the theory's critics in the body of the text, so far as I could see, and neither Smolin nor Woit is found in the index.)
Once you have read Schumm's and Woit's books, or even just Smolin's, you may well decide not to bother with "The Hidden Reality." That is why I gave it just one star, despite the characteristic "Greene-ian" elegance with which it is written. Neither theoretical nor expository elegance constitutes data or experimental proof, and that is what we are still lacking some 30 years into the theory.
N.B.: My review has been criticized in terms of its content and fairness (or lack thereof). I therefore suggest to the interested reader that you read the comments attached to the review, especially those of J. M. Ramirez and G. Wilson, and draw your own conclusions. Also, in one of the recent threads on Woit's blog, written two months after my original post of this review, he said that very few newly minted physicists in the U.S. were now string theorists, or even anti-string theorists, for that matter. Apparently the tide has shifted some within the field of physics in the four years since Woit's book was published.