Michael's Reviews > The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos

The Hidden Reality by Brian Greene
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's review
Sep 18, 2012

it was amazing
bookshelves: non-fiction, science, physics, astronomy

Outstanding update of the current status of modern physics and the projections of parallel universes from various advances. I would have loved to have Greene for a teacher in college. The tour is suitable for laymen with some understanding of physics, as he provides plenty of concrete examples to explain challenging concepts and gives an opportunity to skip more technical sections. For the more knowledgeable reader, a copious appendix is available, replete with the relevant math equations.

Greene works his way through the history and logic behind eight different models of parallel universes and their status in terms of development and progress toward potential verifiability. The only one that I was really familiar with, from a college course on quantum physics 40 years ago, Everett’s 1956 Many-Worlds Hypothesis, is the only one that really bothers me, with its continual “splitting” off of parallel realities at every point where uncertain outcomes like the position of an object is resolved. Greene makes it clear how the interpretation is simpler and more elegant than Bohr’s interpretation. The latter calls for the probability wave of a particle to mysteriously collapses when it is detected or interacted with, effectively throwing out Schroedinger’s equations out whenever a “measurement” is made and restricting their applicability only to very small objects. Despite Occam’s Razor favoring Everett’s hypothesis (the quantum mechanics equations apply deterministically at all times), the interpretation of possible alternative states as each being somehow “real” has always been too absurd to be true to me. It’s a relief then that there is still scientific resistance to the notion and demonstrations of problems with the theory. Greene notes: “I don't expect theoretical or experimental consensus to come in my lifetime concerning which version of reality-a single universe, a multiverse, something else entirely—quantum mechanics embodies.”

The other theories are fascinating and do not call for my alternative choices to have an existence in parallel universes. It was great to get a perspective on the excitement and challenges with string theory and its promise for helping unify the gravitational force with the other forces already in the fold of quantum field theory. The discovery that our universe is undergoing an acceleration in its expansion, and the need for some kind of anti-gravity force (“dark energy”) was a shock to me, so the recent successes of the theory of empty space having an “inflaton” field was satisfying to read about. Greene’s coverage of recent work on the meaning of entropy and information in physical systems was also a pleasure for me.

For a sense of the content of this book, here is a thumbnail sketch of the seven other parallel universe theories covered, as laid out in Greene’s summary chapter:
Quilted Multiverse: Conditions in an infinite universe necessarily repeat across space, yielding parallel worlds
Inflationary Multiverse: Eternal cosmological inflation yields an enormous network of bubble universes, of which our universe would be one
Brane Multiverse: In string/M-theory’s braneworld scenario, our universe exists on one three-dimensional “brane”, which floats in a higher-dimensional expanse potentially populated by other branes—other parallel universes
Landscape Multiverse: By combining cosmology and string theory, the many different shapes for string theory’s extra dimensions give rise to many different bubble universes
Holographic Multiverse: The holographic principle asserts that our universe is exactly mirrored by phenomena taking place on a distant boundary surface, a physically equivalent parallel universe
Simulated Multiverse: Technological leaps suggest that simulated universes may one day be possible.
Ultimate Multiverse: The principle of fecundity asserts that every possible universe is a real universe…These universes instantiate all possible mathematical equations.

The summary chapter was also satisfying to me in attempting to address the following questions:
Is the Copernican pattern fundamental? --Following the 500-year trend that ”the more we understand, the less central we appear”, we now approach the perspective that “our universe itself may not be central to any cosmic order”.
Can scientific theories that invoke a multiverse be tested? --The worry is that ”by invoking a multiverse, we enter the domain of theories that can’t be tested”. He argues that well founded multiverse theories should be able to make predictions which are likely to be testable in our own universe, and hence falsifiable.
How does the multiverse affect the nature of scientific explanation? Traditional approaches for physics aims to use mathematical expressions of physical laws and a set of constants and initial conditions to project what measurable things will be like at a subsequent time. Multiverse theories usefully explore variability in these conditions and laws which must be accepted as a given in a single-universe theory.
Should we believe mathematics? Based on past progress, mathematical theories have had a huge impact on guiding science toward hidden truth. Despite problems in testing the multiverse theories, pushing on them is likely to lead to progress.
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Reading Progress

September 18, 2012 – Started Reading
September 18, 2012 – Shelved
September 21, 2012 – Finished Reading
September 22, 2012 – Shelved as: non-fiction
September 22, 2012 – Shelved as: science
September 22, 2012 – Shelved as: physics
October 7, 2016 – Shelved as: astronomy

Comments (showing 1-7 of 7) (7 new)

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message 1: by Doug (new)

Doug Bradshaw Good grief. I'm barely smart enough to read your review let alone the book. From my minimal knowledge in Physics, all of this seems ridiculously theoretical. Where does god fit in? I admire the way you take so much time to write such a nice review.

message 2: by Michael (last edited Sep 22, 2012 12:55PM) (new) - rated it 5 stars

Michael Man, you're a science fiction fan! You know how daring it is to think of hidden, parallel universes. From the Twilight Zone on down. There is no real math in the body of the book.

If some scientists are making a huff about the Higgs Boson recently, don't you want to know about this so-called "God Particle". And first they said the universe would slow down and grativy pull everything back for endless cycles of big bangs. But now they scare us with all the galaxies accrelerating away endelessly until it is a dark cold nothing. And they blame it on dark matter spawning expansion of space itself. Yeah, you could open you mind for inflaton fields, and learn to feel better about quantum jitters and tunneling creating new "bubble universes." Just as good as sci-fi for perking your sense of mastering the universe. B-D

message 3: by Will (new)

Will Byrnes What fun. Of course in another universe it might be even more fun!

message 4: by Jimmy (new) - added it

Jimmy Shroff To Doug Bradshaw : god is the joy and light we crave more of..... and the good news is that all of this theory, all the multiverses in the omniverse, each in its own dimension, can be experienced eventually since we each have potential bodies corresponding to the 'density' / 'frequency of vibration' of each of the dimensions. As far as the human beings on this planet, we have developed our three dimensional bodies, plus are continuously making use of at least two more refined bodies: since these two bodies and the two corresponding dimensions are not named by physics, metaphysics has stepped in and named them : emotional and mental... such names avoid 'ridiculously theoretical' ideas by giving instant recognition and instant value for lay persons.
The dimensions interpenetrate, making it possible for us to feel and think even while we are on physical earth. When we come to the end of use of our physical body, we continue feeling and thinking, thus experiencing a continuity of consciousness. However even the emotional body (called astral, like a star, named by the Greeks who had managed to penetrate these mysteries practically, and the higher mental body, are not everlasting although they can be used for a very long time if required by the individual.

There are more refined bodies in germ form ... household names of those human beings who trained themselves to develop these bodies (names such as signified by their designations of Christs, Buddhas, Christnas, and a couple of thousand humans whose names are not well known).... these two dimensions may be termed Intuional and Spiritual All the theory and mathematics may be perceived first hand in these dimensions.... right now we just receive a trickle ...enough to keep our brains and hearts busy.


Michael Jimmy wrote: "To Doug Bradshaw : god is the joy and light we crave more of..... and the good news is that all of this theory, all the multiverses in the omniverse, each in its own dimension, can be experienced..."

Thanks for your synthesis. I do regret the idea of universes we can know nothing about, so it's a lovely idea for such an "interpenetration."

message 6: by Stuart (new) - added it

Stuart Michael, I just discovered your really excellent review since I recently saw the 2013 documentary Particle Fever about the LHC launched by CERN in Geneva. It got me enthused about quantum universes and such, but the only layperson books I've read are A Briefer History of Time, The Grand Design, and A Universe from Nothing. Brian Greene's the big string-theory proponent and his books look pretty difficult, but I still want to read this at some point, though all the theories sound incredibly far-fetched, though the problem may be the limitation of our cognitive abilities. Either way, any real hard SF fan will want to sample what "real scientists" theorize about quantum physics, including this book. There's also a rival school that seems intent on debunking this type of work, including Lee Smolin's The Trouble with Physics. Maybe they can have a rap battle for supremacy. Check the Large Hedron Rap: https://www.youtube.com/watch?v=f6aU-...

Michael Stuart wrote: "Michael, I just discovered your really excellent review since I recently saw the 2013 documentary Particle Fever about the LHC launched by CERN in Geneva. It got me enthused about quantum universes..."

Really glad you responded. This was quite accessible, yet disturbing for how much is not settled and how hard it is to feel comfortable with the attempted solutions. Literature, including sci fi, is still struggling to accommodate the Neils Bohr model. Aside from a license to play with parallel universes like in Anathem, The Long Earth, and Dark Matter, and alternative histories a la Dick and Tutrledove, the cosmological physics of the last 100 years has proven largely indigestible by literary imagination. The division into two cultures of science and the arts which so concerned C.P. Snow over 50 years ago is even more at play now. We need writers like Greene to interpret as best they can the story of modern physics for a larger audience. Thanks for the Smolin reference and link.

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