The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos [Kindle Edition]

Brian Green's fascinating book "The Hidden Reality: Parallel Universes and the Deep laws of the Cosmos" is about a growing body of work that is steadily converging around a proposal that our universe is actually one of many universes. He admits that the subject of parallel universes is highly speculative. No experimentation or observation has been established. The point of the book is not to convince us. Its intention is to lay out the intellectual steps and the chain of theoretical insights that led physicists from a range of perspectives to consider the possibility that ours is one of many universes.
He says some people recoil at the notion of parallel worlds. They feel it marginalizes our place and importance in the cosmos. Green's take is different. What matters is whether there exists exciting realms that challenge convention by suggesting what we thought to be the universe is only one component of a far grander mostly hidden reality. The journey so far takes us through nine variations of the multiverse theme - the Quilted, Inflationary, Brane, Cyclic, Landscape, Quantum, Simulated and Ultimate. Each envisions our universe as part of an unexpectedly larger whole, but the complexion of the whole and the nature of the member universes differ sharply. Some are separated by enormous stretches of space and time, other hover millimeters away, in others the very notion of their location proves parochial, devoid of meaning.
Over the course of five centuries we've had to give up our belief in the earth's centrality among our cosmic neighbors, the sun's centrality in the galaxy, the Milky Way's centrality among the galaxies, and even the centrality of protons, neurons and electron in the cosmic recipe.
Greene says, "It's at once humbling and stirring to imagine just how expansive reality may be. If we're part of a multiverse, at best we can learn about our universe, our corner of the cosmos...I don't know how it will turn out. But it's only through fearless engagement that we can learn our own limits."

If you ever wonder what possessed the medieval world to defend and embrace the Ptolemaic view of the cosmos against all comers until the time of Copernicus and for some time thereafter, then this book should provide many people with that same level of discomfort that the defenders of Ptolemy must have felt when faced with the idea of a heliocentric cosmos. It is relatively easy to be wise after the event and scorn the ignorance and stubborness of Ptolemy's guard; even Einstein found the idea of an expanding universe (which is what his original equations told him was happening) to be unacceptable; at least until Hubble provided him with the proof. In a similar vein, Brian Greene's The Hidden Reality takes one on a mind-expanding journey through contemporary versions of Parallel Universes held within the community of astrophysicists and mathematicians who spend their time delving into such matters. At first blush, one might be foregiven for thinking that such concepts are to be taken no more seriously than the world of Alice in Wonderland; at least in terms of their representing our 'Hidden Reality.' However, Greene leads us through each proposal in a clear and concise manner to reveal such concepts as:
The Quilted Multiverse
The Inflationary Multiverse
The Brane Multiverse
The Cyclic Multiverse
The Landscape Multiverse
The Quantum Multiverse
The Holographic Multiverse
The Simulated Multiverse
The Ultimate Multiverse
Along the way, ideas from quantum mechanics and string theory are addressed, along with consideration in the final chapter to the question of the Limits to scientific enquiry about these concepts; most of which might prove impossible to ever actually 'test' in a scientific manner.
This book is not an easy read, although given the nature of the concepts under discussion this is hardly surprising. However, Greene manages to provide a relatively clear explanation of the concepts, without resorting to the need to drown the reader in complex equations and mathematics. At the same time, anyone with a reasonable grasp of scientific methodology and some background in physics and mathematics will probably find this a fascintating read. To really get to grips with the subject matter would involve a more careful rereading and study of the contents, but for an overview of the ideas an initial diligent read will suffice.
Certainly, I should recommend this book to anyone interested in finding out about current thinking and ideas around this subject. I totally disagree that this book could have been reduced to 20 pages and that the remaining 95% is waffle as suggested by one other reviewer. This is not light reading, but nor is it waffle. Indeed, it is impressive precisely because it keeps focused throughout and ties the various ideas together in a coherent and meaningful manner. Above all, even if you regularly read books about philosopy of mind, metaphysics, epistemology, science fiction relating to parallel universes, newtonian and quantum mechanics the ideas in this book will certainly provide some stimulating and entertaining food for thought.

"When we hand over the steering wheel to the mathematical underpinnings of the major proposed physical laws, we're driven time and again to some version of parallel worlds." - from THE HIDDEN REALITY

When I entered college and foolishly took over the wheel of the vessel "Engineering Major" that would presumably steer me towards my life's profession and gainful employment, I soon ran hard aground on the reef of Differential Calculus. It wasn't until I abandoned the wreck and transferred to the good ship "Life Sciences Major" that I safely arrived at where I am today. I've never gotten over that perilous time on the rocks. So, it was with some trepidation that I picked up THE HIDDEN REALITY by physicist Brian Greene. As an occasional buff of sci-fi lit, the concept of parallel worlds has always been of casual interest, but perhaps, with Greene's book, I was setting sail into dodgy waters once again.

Over the course of his discourse, the author discusses nine parallel universe, or "multiverse", concepts derived from the mathematics (as opposed to direct observations) of the Relativity, Quantum and String Theories: Quilted, Inflationary, Brane, Cyclic, Landscape, Quantum, Holographic, Simulated, and Ultimate. I'm not even going to attempt a further summary of the material as it would only invite ridicule and cause my subsequent humiliation.

The surprising fact is that I managed to make it through to the end, albeit clinging desperately by my fingernails to the edge of an event horizon such that I didn't fall screaming into the Black Hole of Total Bewilderment. This ultimate survival I attribute solely to Greene's skill at conveying the concepts without resorting to descriptive (to some) mathematical formulae. (Ok, ok, he threw out an E = mc2 equation once or twice, but anything heavier he relegated to the Notes at the end for interested numbers geeks. Suffice it to say, I didn't even glance at that section.) Rather, he illustrated key points with drawings and examples that can likely be appreciated by math-challenged readers such as me. Perhaps this is what makes him a best-selling author.

Now that I've finished THE HIDDEN REALITY, to say that I've a comprehensive grasp of the topic would be a mind-boggling overstatement. Were I to take a test on the volume's contents, I might manage a C-, and that's if it was multiple choice format and not essay. I consider this passing grade, rather than an F, to be a solid accomplishment attributable mostly to Greene's teaching skills. And though I've not read any other expert on the subject to whom I can make comparison, I suspect he's a much better teacher than most. Therefore, five stars for the didactic quality of his book. Don't look for any cheeky humor, though; Greene is no Bill Bryson of A Short History Of Nearly Everything.

Now, if I go outside and gaze at the night sky perhaps visible through the Greater Los Angeles light reflected off the haze and/or smoke, I'll most certainly think to myself, "Wow, could there be more than one those?" One must always be open to a sense of wonderment.

And, in case you're curious, a "flop singularity" is a spherical portion of space compressed to an infinitesimal size.