The Allure of the Multiverse: Extra Dimensions, Other Worlds, and Parallel Universes

by Paul Halpern

“A rich and rewarding history of one of the most astounding ideas in physics and astronomy” (Marcia Bartusiak) – that the universe we know isn’t the only one   Our books, our movies—our imaginations—are obsessed with extra dimensions, alternate timelines, and the sense that all we see might not be all there is. In short, we can’t stop thinking about the multiverse. As it turns out, physicists are similarly captivated.     In The Allure of the Multiverse, physicist Paul Halpern tells the epic story of how science became besotted with the multiverse, and the controversies that ensued. The questions that brought scientists to this point are big and Is reality such that anything can happen, must happen? How does quantum mechanics “choose” the outcomes of its apparently random processes? And why is the universe habitable? Each question quickly leads to the multiverse. Drawing on centuries of disputation and deep vision, from luminaries like Nietzsche, Einstein, and the creators of the Marvel Cinematic Universe, Halpern reveals the multiplicity of multiverses that scientists have imagined to make sense of our reality. Whether we live in one of many different possible universes, or simply the only one there is, might never be certain. But Halpern shows one thing for how stimulating it can be to try to find out. 

Genres: Science, Nonfiction, Physics, Audiobook, History, Philosophy, Quantum Mechanics

284 pages, Kindle Edition

First published January 16, 2024

About the author

Acclaimed science writer and physicist Dr. Paul Halpern is the author of fourteen popular science books, exploring the subjects of space, time, higher dimensions, dark energy, dark matter, exoplanets, particle physics, and cosmology. He is the recipient of a Guggenheim Fellowship, a Fulbright Scholarship, and an Athenaeum Literary Award. A regular contributor to NOVA's "The Nature of Reality" physics blog, he has appeared on numerous radio and television shows including "Future Quest" and "The Simpsons 20th Anniversary Special".

Halpern's latest book, "Einstein's Dice and Schrodinger's Cat," investigates how physicists Albert Einstein and Erwin Schrodinger battled together against the incompleteness and indeterminacy of quantum mechanics. Their dialogue inspired Schrodinger's famous thought-experiment about a cat in a box that is in a mixed state between life and death until it is observed. They struggled to find a unified field theory that would unite the forces of nature and supersede quantum weirdness. Sadly they would never find success and their efforts would lead to a fiasco.

More information about Paul Halpern's books and other writings can be found at:
phalpern.com

Reviews

[Jake · Rating 2 out of 5]

It's not really so much about multiverses?

The beginning gives an introduction and a history about the philosophical and theological roots of multiverse theory, and the end goes into the portrayal in science fiction. The very large middle is a deep dive into quantum mechanics, astronomy, and theoretical physics. Every so often there would be little aside about how this or that theory has something to do with the idea of a multiverse. But most of it feels like a primer on theoretical physics for theoretical physics's sake. Maybe I'm wrong. I don't have a background in physics, and everything I know about the subject comes from reading books by scientist authors such as Neil de Grasse Tyson and Carlo Rovelli. In other words, maybe I'm just a dumb-dumb and I really need it spoon fed to me just what all this stuff about Cosmic Background Radiation and the Mixmaster Universe has to do with Everything Everywhere All at Once.

I read an ARC and it may differ slightly from the final product.

[Peter Tillman · Rating 3 out of 5]

Excerpt from Science magazine review:
"Science fiction writers are fascinated by the idea of a multiverse. So, too, are physicists like Paul Halpern. In The Allure of the Multiverse, Halpern explores the science behind the popular plot device. As reviewer Melanie Frappier explains, the book introduces readers to all sorts of people who have played parts in multiverse theory, from a 19th-century French revolutionary to some of the most famous names in physics. But ultimately, it’s all in service of the science. “This is a book of physics, not of philosophy," Frappier writes.
Full review: https://www.science.org/doi/10.1126/s...

Book excerpt: designing a theoretically traversable wormhole:
https://lithub.com/the-physics-of-fic...

This is a good book, and the Science review is the one to read first. This is a topic I have been interested in for many years. My own training is as a geologist and chemist, and I am also an avid science-fiction reader. So much of the book was familiar territory to me. Halpern's writing, though very good, does get repetitive at times. But there was enough new-to-me stuff to add to the pleasure of reading. For me this was a 3.5 star read. I'm rounding my rating down because I skimmed familiar material. But the "wisdom of crowds" currently averages 3.85 stars, and you may well find this to be a 4-star or better book. Recommended reading.

[Jacquelyn Dohoney · Rating 5 out of 5]

The arc for this book came out right after I finished reading Blake Crouch’s Dark Matter so I was pretty excited to dive into it. I’m a fiction writer, but I can’t write sci-fi to save my life. The research behind sci-fi novels, though, is so fascinating to me. Shows like Sliders and Stargate SG-1, while entertaining and dramatic, have made millions of people wonder, “Is it possible?” While I don’t have the answer to that, I know that all of our science-based knowledge that we think of as law was at one time considered theoretical. The fact that earth is spherical and not flat was once considered fringe science. So who is to say that multiverses aren’t possible? I really enjoyed reading this book. It was interesting to see the part that the history of physics played in the field, from confirmed physics to theoretical physics, and the future of theoretical physics. And for someone who has taken a couple of physics classes (mostly forensic science, chemistry, and biology), this book was extremely easy to read.

Huge thanks to Basic Books and NetGalley for sending me this ARC for review! All of my reviews are given honestly!

[Ali · Rating 4 out of 5]

“As cosmologists try to fathom the unimaginably vast, high-energy theorists and experimentalists attempt to comprehend the extraordinary small: the realm of subatomic constituents, from quarks and leptons to exchange particles and the Higgs boson. Increasingly, physicists realize that there is a profound connection between the two extremes. In recent decades, the age-old quest for unity in the realm of subatomic entities and natural interactions has led to an astonishing link with the multiverse of bubble universes in eternal inflationary cosmology.”

Halpern attempts here to tell the story of how physics has arrived at the many worlds theory, ideas about multiverses and even the possibility (or not) of human backwards time travel. He starts back several centuries and brings us right up to M-theory, with each chapter tackling a different theme, but working forwards in chronological order (you get the feeling Halpern is of the no-backwards-time-travel view). It is an ambitious task, and I suspect that Halpern has done as good a job as it possible, even as the result can be more challenging than a general overview would generally (heh) want to be.
Part of the problem is that physics concepts are often mathematical in origin. Non-mathematicians unhelpfully don’t think in equations, so turning these ideas into language often involves a lack of precision. It always involves a lot of words, and Halpern has limited space for words in his need to keep us moving forward. He eschews metaphors and analogies - often the go-to option for science writers trying to explain theoretical physics. This makes sense when the audience you are writing for is one that wants to understand how the science informs the multitude (heh) of multiverse stories in popular culture - more metaphors hardly seems helpful. But the result is a lot of concepts, generally well explained, but piling on top of each other relatively rapidly. As a non-physicist who reads a lot of popular science, I was very grateful for having read clearer, book length treatment on several of the mentioned theories, and even then I was struggling to keep track at times of how it all fitted together.
Having said that, the book is fabulous at tying the story together into something that enables all of the various ideas to fit into a common history. This did help - immensely - to understand how we got to where we are, why these ideas remain contraversial any where theoretical construction is more trusted and where less. I wouldn’t recommend it as a starting point, but I would recommend it to someone at an early part of their journey (or like me, with an old brain things drop out of if not re-read). And it is admirable in its insistence that both believers and doubters deserve respect:
“Acceptance of multiverse models in science clearly is a matter of taste. Many noted figures—for instance, writer John Horgan—remain vehemently opposed to any type of multiverse, dubbing the whole notion “unscientific.” In contrast, other thinkers, such as Martin Rees, astronomer royal of the United Kingdom, feel reasonably confident—given the need to fine-tune of the constants of our universe, possibly by contrasting it with others—that a multiverse exists. As he remarked: About 15 years ago, I was on a panel at Stanford where we were asked how seriously we took the multiverse concept—on the scale “would you bet your goldfish, your dog, or your life” on it. I said I was nearly at the dog level. Linde said he’d almost bet his life. Later, on being told this, physicist Steven Weinberg said he’d “happily bet Martin Rees’ dog and Andrei Linde’s life.” Sadly, I suspect Linde, my dog and I will all be dead before we have an answer.”

[Doctor Moss · Rating 4 out of 5]

Multiverse theory is hot, both within physics and astrophysics, and within popular culture. Halpern’s title, while no doubt a marketing choice, conveys a theoretical pull toward multiverse theory in physics and astrophysics.

Halpern rightly traces the history of the “multiverse” back prior to current physical theories. The term originated with the philosopher William James’ moral theory in the late nighteenth century, but the idea goes much farther back, even to classical thought. The term “universe” itself has a complicated history, much less the idea of a multiplicity of them. Until the early twentieth century, galaxies, once discovered to be external to our own Milky Way galaxy, were referred to as “island universes.”

There are different types of multiverses, even within physics. Hugh Everett’s interpretation of quantum theory, called the “Many Worlds Interpretation,” refers to a branching of realities as quantum probabilities are resolved, producing new “worlds” in which each possible value of a measurement is realized. The Many Worlds theory gives rise to popular depictions of “alternative universes,” like in the novel, The Man in the High Castle, or in the Marvel Comics stories.

Everettian theory is increasingly mainstream within physics, and Halpern spends some time on it, but it’s not really the focus of his discussion.

His discussion follows a reconstruction of the conceptual developments that lead in physics to solutions to problems in Big Bang cosmologies. Those theories, particularly addressing problems in accounting for the uniformity of our observed universe, its flatness, and its fine-tuning of seemingly variable factors, like the strength of gravity or our universe’s vacuum energy, toward the formation of galaxies, planets, life, and us.

One solution to that apparent coincidence of fine-tuning, proposed in the later parts of the twentieth century is the “anthropic principle.” In various forms, that principle provides a filtering mechanism to explain how it is that our universe is so well-suited to life (and us). We could not exist in any universe that did not permit the development of galaxies, stars, planets, and life, so we must exist in one that does. There may well be many universes “out there” much more poorly suited for those things, or entirely excluding them. We must be in this one, or at least in some small subset of universes that permit our existence.

In the late twentieth century, Alan Guth and collaborators developed what was thought to be a solution that preserved a single universe theory and did not necessitate anything so boggling as the anthropic principle. Inflation, as a speculative description of the very first moments (really nano-moments) of the universe’s existence, explained many of those coincidences.

But as inflation theory developed, it actually led to a multiverse theory itself, “eternal inflation.” If inflation happened, there is no reason to suppose it must have happened only once, or that it must have stopped anywhere and everywhere. Our universe could, and likely by theory, would be one of many “bubble universes,” some of which continue to inflate, some of which exclude the development of galaxies, stars, planets, life, and us, and some of which afford that development.

Thus the “allure” of the multiverse. Theory keeps leading us back to it, even when we think we’ve found a way to escape it.

The supposition that ours is not the only “universe” strains, for many, the limits of properly scientific theory. By their very nature, we will never experience those other universes, Everettian or inflationary. No one will ever get into some sort of universe-traversing ship, visit another universe, and come back. So their existence remains entirely hypothetical, unconfirmed, and beyond empirical verification by its very nature.

Setting aside for the moment suggestions for how evidence of the existence of bubble universes other than our own might be detected (“bruising” or, less dramatically, detection of intersections or collisions between expanding universes), it’s interesting to think a little bit about this debate over the scientific status of multiverse theory.

The debate rests centrally on this point of whether or not multiverse theory is subject to empirical test. Scientific theories, in one mainstream view of the job of science, must in principle be falsifiable, i.e., there must be crucial empirical tests whose outcome will show the theory to be validated or invalidated. Otherwise, the theory is not scientific and not worth entertaining.

Can we be sure that an adequate theory of the universe (of “reality” if you want to call it that to avoid limitation to one universe) is subject to empirical test?

The universe may well be beyond observation. In fact it is, regardless of whether our universe is part of a multiverse. The universe, owing to its expansion, is larger than the portion of it that we can observe. And that observable portion becomes smaller and smaller, in relation to the whole, all the time.

More importantly, once we draw back to consider the general relationship between observability and reality, to say that multiverse theories cannot be valid descriptions of reality because they would defy observational test is very odd. The universe is what it is, and what we can observe is, or may be, something else. Having observability rule reality has the two in the wrong order.

That doesn’t mean speculation should be licensed without bounds. Sometimes physicists deride “unscientific” theories as “philosophy.” Philosophers do not abide unbounded speculation. In fact, there are works by philosophers of science that specifically address the evaluation of scientific theories on non-empirical bases. See for example Richard Dawid’s String Theory and the Scientific Method (Dawid is a former physicist who found physics needing resolution to philosophical questions to proceed on its way).

A consequence of a recognized rupture between reality and observability would be that physical cosmology (or “scientific” cosmology) would need to give up any claim to describe all of reality, if scientific theory requires test by observation.

That would be interesting.

[Annarella · Rating 5 out of 5]

Multiverse makes me think about Pratchett but there's more to this world than that.
It's an informative and well researched book, not always easy to follow but fascinating and intriguing.
Highly recommended.
Many thanks to the publisher for this ARC, all opinions are mine

[Steve · Rating 4 out of 5]

There are certain aspects of the book I really liked. The best part of the book was the discussion of falsifiability and what constitutes science. Halpern uses some great analogies to get his points across and he couples this with a conversational tone and some humour. There is also a lot of history of science and some pop culture references. Despite the strengths in the writing, there were some areas that were over my head but I am not sure that better explanations are possible without pages and pages of equations - happily this book had none. Overall, this was a worthwhile read. Thank you to Netgalley and Basic Books for the advance reader copy.

[Craig Werner · Rating 2 out of 5]

Disappointing in large part because the title's deceptive. The vast majority of the book consists of a fairly garden variety summary of the evolution of 20th and early 21st century Physics. The book begins with a quick and mostly obvious survey of how parallel universes, etc., show up in pop culture. But what I wanted was something serious about how the questions raised by the approach play out in much more specific terms than Halpern offers.

[Ryan Berger · Rating 3 out of 5]

To avoid any misunderstanding: this is emphatically *not* a book that delves into the philosophy, narrative, spirtual or spiritual consequences of the capital M (and possibly trademarked) Multiverse and is instead a recap of the last 100 years or so in experimental physics and mathematics and explains why there is scientific appeal in barking up a tree where nothing is observable or testible.

For writing that deals more in what I feel the title of this book is promising, I recommend tracking down essays on parallel universes by the brilliant Ted Chiang and Sasha Sagan, both of which appear in the underrated " A Vast, Pointless Gyration of Radioactive Rocks and Gas in Which You Happen to Occur". This deals more directly with the fantasy of paths not chosen, parallel worlds, and dopplegangers.

These, of course, are all complete fabrications which have minimal bearing on what even the most out-there "real" science is suggesting. Nobody is suggesting there is a membrane we can slip between and end up in a nearly-identical parallel universe with its own Earth-2 in it.

What the multiverse actually refers to is a hypothesis suggesting that there are multiple "universes," best viewed as different regions or sectors, all governed by different laws of physics. This would help explain why our universe is the way it is and why it feels so specific in producing our way of life. It seeks to achieve uniformity among all physics and act as a "theory of everything".

Which would be very convenient if it were true, as having a unified basis of physics would make more of the universe make sense.

Fascinatingly, this flexibility a multiverse theory provides is also why it attracts scrutiny from some in the physics community (to get a sense for how wide the acceptance of a multiverse is, Halpern uses a scale asking other scientists if they'd bet their goldfish, their dog, or their life on the existence of a multiverse. At this time, consensus appears to settle on "bet the dog"-- perish the thought). Skeptics say it is all too easy to chase phantoms and find mathematical safety-valves and loopholes that makes the work look mighty fine if you just add another annex to a formula similar to the way people stitch wings onto a house, regardless of what it does to the overall composition.

Similarly, that "allure" of the multiverse inspires Ahab-like devotion to proving the whitest of all whales in experimental physics that also would seem to have next to no practical value for humanity, even if we could prove it were true. We stand to gain very little by proving that multiverses exist as we currently understand them (and again-- nobody has suggested with a straight face that anything like multiverses in fiction is anything remotely plausible). The result is a theory that attracts glory-seekers motivated by achievement rather than practicality.

Unfortunately, I'm making the book seem more interesting than it is. While Halpern is not completely incomprehensible to a layperson, his writing is wholly unbeautiful and does not rely on metaphor or analogy and instead lays brick after brick, building on top of itself with theory after theory. It is fairly boring much of the time as Halpern is not especially interested in giving lip service to the stakes and the politics of this field, but rather a history of how we arrived at the theories we're currently playing around with today. As a result, it's hard to know who exactly is going to get a lot out of this book. It would seem to me that Halpern is somehow both inaccessible (or at least, does not write for people without a familiar background in physics and mathematics) and also not thorough enough, offering precious little commentary in favor of a recap of the story so far.

The final concluding chapter is a rather clumsy survey of the moment Multiverse fiction is having right now. It is never more plain that Halpern is not the writer to channel what I might call the "romantic" or "thematic" appeal of a multiverse than in this concluding chapter, though I did genuinely laugh and nod my head when he suggests that the major appeal of multiverse fiction appears to be what it does for franchises and sweet sweet cameos. Drag that damn cinematic universe, Halpern!!

A good frame that asks why we should even care if a multiverse, in the hypothesized form, exists--though learning a bit more about it killed much of my interest in finding out more.

[Dan · Rating 4 out of 5]

My thanks to both NetGalley and the publisher Basic Books for an advanced copy of this look at the history of one of the most intriguing, controversial, and through media most popular and yet misunderstood ideas in physics, parellel worlds.

All of my science learning and knowledge has probably come from reading books and ingesting science fiction in all shapes and forms. My school was not big on the idea of science, in fact education seemed to get in the way of pep rallies, and all sorts of other noneducational times at school. College I might have taken some classes, but I was going to change the world of literature so Id didn't take science classes out of what I needed. As I have become older I have read a lot more and enjoy many of the books I have come across. However it is probably science fiction writers that have been been teachers. And that is both good and bad. My first experience with the idea of parallel worlds was either the Mirror Universe in Star Trek, or the stories of Earth 1 and Earth 2 in DC comics. My understanding is from a story I read years ago by the great writer Larry Niven. All the Myriad Ways was a story about people realizing there were worlds were they might or might not exist, alone, happy, sad, the same of different. And what happens after. Read the story, it's quite good, and will stay with you. For a better understanding of the idea of multiple universes I highly recommend this book,The Allure of the Multiverse Extra Dimensions, Other Worlds, and Parallel Universes by writer and physicist Dr. Paul Halpern. Dr. Halpern looks at the history of this controversial idea, the many arguments for against, and how media has used it for story telling purpose, while still leaving people in the dark about what it truly means.

The book begins with a look at the worlds around us and the skies above. While we are still learning so much about what is out there, we are in a way limited in how we can find out. Our rockets are still slow, technology can only go so far, and while we keep discovering strange new worlds, most of them will remain as images. Halpern looks at the idea of wormholes, also made popular in movies, and the importance of mathematics has in these grand new ideas. Halpern discusses the idea of the Many Worlds Interpretation which is basically there are many worlds which exist in parallel to us at the same time and place. Many of the names will be known, arguments for and against are presented and shown. In addition the influence of these ideas on popular media, especially in books and movies is examined.

I was a little vague in my summation as there is a lot going on in this book, and being a layperson I am afraid of presenting wrong information. I enjoyed this book quite a bit. Some sections might have made me read something a few times, but all in all this is a very well written history of a very large idea in physics. Some of this might not be new to veteran science readers, but much was new to me, and explained in such a way that I was able to understand what was presented. Halpern has a nice style, one can tell Halpern is familiar with the subject, and he presents everything in a way that makes sense. The controversies were kind of amusing, as I am sure only a few people even understood the ideas behind it at the time. Though one can see why there could be a problem, with such a radically strange idea.

A very well written history about science and physics that will be of interest to many people. One I think is well-written and well-presented. A book to keep the brain thinking while the snow is falling. And makes one wonder what the you on a parallel world might be reading.

[Brian Clegg · Rating 5 out of 5]

What with multiverses and metaverses, you just can't move for verses at the moment (amusingly, the 'verse' part essentially refers to a turn, which makes no sense in either case). 'Multiverse' as a concept was always going to be a trifle confusing, as 'universe' is supposed to refer to everything in existence, but as we will see, there are plenty of different ways, both philosophically and physically, that the term is applied to something beyond the familiar, four dimensional universe.

Paul Halpern packs plenty into this book - in order to put the various kinds of multiverse concept into context he pretty much goes through quantum physics, Big Bang cosmology and string theory (plus a touch of loop quantum gravity) in a fair amount of detail. We see how the most straightforward multiverse concept of a series of bubble universes in the same normal spacetime has been used to explain the fine tuning of the universe or is put forward as a consequence of the contentious notion of eternal inflation. But we also get the quantum multiverse of the Many Worlds Interpretation, the potential for brane universes that collide, the multiverses that are effectively generated by adding extra dimensions to the familiar ones, and the statistical multiverses where a theory such as string/M-theory gives us inconceivably vast numbers of alternate possibilities for the state of a universe.

Halpern tries hard to be neutral, always pointing out that there is not a consensus acceptance of any one of these theories - they all have plenty of cosmologists and physicists who think they don't make sense. We get both sides of the argument, though you do get the feel that the author would rather like a multiverse theory to be true, if only for the fun of it. Many of these theories are considered by their detractors to be ascientific in the sense that while they (to some degree) fit what observe, there is no way of disproving them - they can feel like clever people playing with maths that will never be anything more than mathematical puzzles and diversions.

Although Halpern's writing style is approachable, he does pack in so much that you sometimes have to let statements go over your head and just get on with it in the hope it will eventually all make sense (on the whole, it does). I'm disappointed he doesn't mention the mathematical error in the strong anthropic principle argument that says fine tuning implies a multiverse. He also revivifies the Bruno myth, referring to the 'assertion by sixteenth-century Italian philosopher Giordano Bruno that there are myriad worlds in space - which led, in part, to him being burned at the stake.' Bruno was martyred for religious views - his cosmological speculations were suspiciously similar to those of Nicholas of Cusa from 100 years earlier, who suffered no such fate, instead being made a cardinal.

I am not a great fan of highly speculative 'science' that is never likely to have evidential claims that can be falsified. However, I surprised myself by very much enjoying this journey through the weird and wonderful speculations of some leading cosmologists and mathematicians. Recommended.

[Esther · Rating 3 out of 5]

I have mixed feelings about this one!

It's an exploration of the history and development of scientific theories regarding multiverses and parallel dimensions. I was very excited to get into that! There were some very fascinating sections, such as Nietzsche's eternal return theory and how scientists and philosophers of different eras went back and forth on how 'out there' MWT needed to be to actually take every variable into account. The writing style was quite conversational at times, which was both enjoyable and a great aid in making complex theories easier to grasp.

However I would caution that you'll need at least passing familiarity with/understanding of some foundational physics concepts to really grasp the theories discussed here. Physics has always been the science I struggled with the most, and that was definitely to my detriment when the book got into quantum theories and particle physics. It's a fascinating discussion, but there were definitely sections that just went over my head completely! I feel like if the writing style was more uniformly conversational, instead of dipping between that and strictly academic paragraphs, it might aid in facilitating understanding for readers who are less familiar with physics concepts.

[Patrick J. · Rating 4 out of 5]

As a part-time writer, I found the book to be an easily-read treatise on the concept of the multiverse. The author avoids English lit and physics jargon. He clearly presents how the multiverse concept relates to spiritualism, Hilbert mathematics and Nietzsche's infinity that emerged in the 19th and 20th centuries. He shows the heritage of the concept into the 20th century with multiple dimensions, Einstein's relativity theories, and quantum mechanics. He shows how the concept evolved differently among physicists and science fiction writers of the 1960s.
Understanding the origin, history, and arc of concepts seems like a good thing for a writer to know, but I wonder who else would find this book interesting? If you like understanding the history of ideas, then this is a book for you. Halpern includes a generous bibliography and useful footnotes. I will remember this book and look for other works by Halpern in the future.

[Phil · Rating 4 out of 5]

Not gonna lie. If I had signed up for a class on this topic in college and the first book to read was this one, then I’d have found myself running to the school administration building to drop the high level course and sign up for something a lot easier for a liberal arts guy like me. Perhaps something on, say, The Allure of American Pop Culture, which would be a lot more in my wheelhouse.

In the interest of time and prevention of a headache, I basically skimmed it. That’s not say it’s a bad book, but it’s just on a much higher level than I care to spend a lot of time on at the moment.

Probably best to keep this one on the shelf for digestion in small bites, unless you’re already well on your way toward completion of a Masters or PhD in physics. If that’s you, you’ll probably love it.

[David · Rating 3 out of 5]

While the subject is absolutely fascinating, the book mostly fails to be interesting. Rather than focus on the various types of "Extra Dimensions, Other Worlds, and Parallel Universes" as promised by the title, Halpern instead delves deep into the history of the development of various cosmological, quantum mechanics, and particle physics theories. This approach ends up as a mishmash of biographical profiles of the researchers and snippets of interviews with the actual theories and criticisms, all of which ends up being only tangentially related to the supposed topic.

As a result, it's difficult to get a good understanding of the science, and the philosophical commentary just makes it more abstract and doesn't really clarify the inherently weighty content.

[Gretchen · Rating 4 out of 5]

This was an interesting overview of various schools of thought surrounding multiverse theories, mostly in science but with a bit of philosophy thrown in. I'm not a physicist by any means - the most I've studied it was in Honors Physics in high school - but I knew enough to understand most of what was being explained. Overall, it's an interesting read that shows how much we don't - and probably will never - know. The discussion of multiverses in pop culture and how they bend the actual science was what I found most intriguing.

[Bill · Rating 3 out of 5]

I made it 2/3 through this book before stopping. There is a reason I couldn't make it through calc-based physics in college - trying to explain quantum mechanics and theory, etc. was going to be a leap of faith for me. A good start in trying to understand parallel universes, though I would have wanted to hear more about the dimensions than the scientists.

If you can understand the psychics behind this you will do just fine. I can understand some of it, just not ALL of it. I will try again...just a different book.

[Philemon - · Rating 3 out of 5]

This should have been a fascinating book. Too much of it was a plodding retell of 20th-century physics. The last sections contain everyone and his physicist brother's multiverse variations, not excluding sci-fi books and movies. By the end a reader may feel as if trapped in a popcorn machine.

It would have been better to focus on the pros and cons of each major flavor of multiverse (as Max Tegmark and Sean Carroll have summarized) as well as the anthropic principle and other arguing points that will ultimately decide whether the multiverse becomes a dominant paradigm.

[Roy Kenagy]

DMPL. EXAMINED 2024_02_01. WORLD ENOUGH AND TIME. KIRKUS: "an ingenious slog that may enlighten those with college courses in relativity and quantum theory under their belts. Cutting-edge physics for the educated layperson." LJ STARRED: "This expert untangling of complicated concepts will kindle curiosity and awe for quantum physics. An excellent recommendation for both science-fiction enthusiasts and readers of popular nonfiction. PW: "thought-provoking if challenging..."

[Jerry Hillyer · Rating 4 out of 5]

A fun book if you're into science fiction. Not so fun if you're into actual science fact. This book is full of speculation and hypothesis, a lot of interesting and important history, but very little 'truth' about the so-called multiverse. Halpern isn't overly hostile to religion which was refreshing, but he's not wholly supportive of metaphysics either.

It was a good read, but of the writing of speculation there is, apparently, no end.

[Bart Stuck · Rating 5 out of 5]

Phenomenal

This popularization of modern physics theories is exhaustive in scope yet very readable and compelling g using examples and analogies to describe cutting edge experiments and theories

The yoga sutas of patanjali describe in book 3.25 to 3.30 special capabilities obtained via deep meditation which enable direct observation of the start of this universe to answer the open questions raised in this book

[Ian Welke · Rating 5 out of 5]

It's rare that a book is exactly what you're looking for, but this came as close to what I was looking for as one might imagine. I wanted a book to help build on other books and essays I'd read on the subject as I'm prepping a book with a physicist point of view character and this did that. It also provided plenty of fairly trippy mind blowing paragraphs to enjoy. Even the cover art looks like a Yes song is about to play. Loved it.

[Elissa · Rating 3 out of 5]

I read this because I was looking for an explanation of scientific ideas about the multiverse for a popular audience. This was not quite that book. It was more about whether the idea of the multiverse can really be considered “science” or not. And in terms of the popular audience, this partly worked. The author writes in such a way that he brings in examples that are understandable—analogies—at times, but other times I felt myself getting lost in the technical jargon.

[Colleen · Rating 2 out of 5]

For a book suposedly about multiverse theories, not much of the book actually discusses multiverse theories and only briefly touches upon how pop culture depicts multiverses. The majority is a very hard-to-follow exploration about dimensions, and why/how the universe is expanding. It's not an easy read if you're not an astrophysicist or quantum physicist or whatever.

[Normandy · Rating 2 out of 5]

Way too much discussion of pseudo-scientific discussion of novels, short stories, movies, and TV was a waste of time. I wanted to dive into the multiverse stuff but spent hours listening to the backstory of the history of physics and quantum mechanics. This book is not for someone with more advanced knowledge of the area.

[James Hendrickson · Rating 4 out of 5]

Comprehensive for a novice

This is a thorough and comprehensive overview of quantum and string theory as it relates to multiverse ideas. It does a good job of covering the history of multiverse ideas and some very recent papers and treatments of it. I would say it was maybe a little too advanced for me but still really good just the same.

[Emily · Rating 4 out of 5]

Definitely would not recommend this to people not familiar with research and how academics talk about ideas, but I learned a lot about competing theories in astrophysics. And a lot of the stuff I learned in my undergrad astronomy course has a home now.

[Kate · Rating 4 out of 5]

I enjoyed the parts of this that I paid attention to very much. Unfortunately, I found the narrator easy to tune out. And that is very unfortunate because what I gleaned was entertaining, informative, funny and well written.

[Ian · Rating 3 out of 5]

3.5* I thought this was going to provide a cultural context alongside the evolution of the science, but in the end it is just another pop-science overview of some of the theories. Competent enough, but nothing much to distinguish it from many similar overviews out there.

[Emily M · Rating 4 out of 5]

25% being sick of multiverses in media, 75% actual explanation and history.

summarizing sentence: "in short, while many of the multiverse explanations sound weird, some of the major alternatives seem equally bizarre."