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A carregar... ## Our Mathematical Universe (edição 2015)## por Max Tegmark (Autor)
## Pormenores da obraOur Mathematical Universe: My Quest for the Ultimate Nature of Reality por Max Tegmark
Books Read in 2019 (2,282) A carregar...
Adira ao LibraryThing para descobrir se irá gostar deste livro. Ainda não há conversas na Discussão sobre este livro. I never know how to review books like this. On one hand, some chapters were brilliant and got my mind spinning in a way that most books don't. On the other, my god was most of this book a slog. It suffers from the usual pop-sci problems: dumbed-down enough to not really represent the subject very well, but not far enough to be interesting to a layperson. As such it wobbles uneasily in limbo; taking four of its thirteen chapters to describe different kinds of multiverses---most of which turn out to be indistinguishable in the end :/ The first two chapters are quite good, and answered some of my burning curiosities in life. "How do we /know/ the universe is 14 billion years old?" It also presented quantum lensing in a way that really connected with me, along with some tests we can run to convince ourselves about it (though, interestingly, not tests we can ever tell anyone else about. Quantum weirdness at its weirdest!!!!) It ends in a philosophical mess of "maybe our universe IS REALLY MATH" and kind of waffles its way through what this means and what it would look like to humans. As best I could tell (I started skimming around here because boooooooring) the argument double- or triple- counts the anthropic principle as evidence for WE ARE REALLY AND TRULY MATH. And even if it does, like, who cares? There doesn't seem to be any testable hypothesis here, and Tegmark's beliefs don't seem to be paying rent. I'll leave you with this: if you're REALLY EXCITED about this book, you'll probably find something of value here. Don't be afraid of skimming along though; Tegmark sure could have used an editor who was sympathetic to the reader. If you're not REALLY EXCITED (or if you've read any amount of Yudkowsky/Bostrom) you're probably not going to find a lot here. I started reading Our Mathematical Universe in January 2014, and here I am, almost two years later, just now finishing it. On the first try, I was only able to get about halfway through, and in February of that year, I set it down (there are always, of course, other books to read). But I wanted to come back to it, and in December 2016, I started skimming through the parts I'd already read, and picked it up again. The book's strengths lie in Tegmark's provocative ideas; his apparent mastery of the history and present state of the subject matter; and his ability to bring dense and arcane topics to a general audience. However, the book is not without flaws, which leads to my four-star rating.Who am I to critique such a book? I'm neither a mathematician nor a cosmologist, though I have strong interest in both topics. As Tegmark admits throughout the book, the topics he addresses are by no means set in stone, which helps my case somewhat. My first issue is editorial and has nothing to do with the subject matter per se. I don't care for the subtitle: "My Quest for the Ultimate Nature of Reality." While Tegmark is well-known in the cosmology and physics communities (a blurb before the title page proclaims that he is "author or coauthor of more than two hundred technical papers, twelve of which have been cited more than five hundred times"), the subtitle begs the question why the general reader should care what Tegmark's view of his quest is. He is not (yet) in the popular consciousness the way a Carl Sagan, Stephen Hawking, or even Bill Nye is. This is not to say that Tegmark doesn't deliver on the subtitle; he does in fact state that the book is "a scientific autobiography of sorts" (12). And while this format allows him to deliver his message in a sometimes folksy, anecdotal way, it left me wanting something more authoritative. At any rate, this is a minor qualm. One item I did take issue with--and to be fair, Tegmark is far from being the first transgressor--is a brief quote that was slipped in toward the beginning of chapter six, which impacts one of his main theses in the book (the concept of the multiverse), and indeed, many assumptions about all of cosmology. Tegmark writes: "if you roll the dice enough times, even the most unlikely things are guaranteed to happen" (122). Apparently lost on Tegmark is the irony of the falsehood of his statement, which is apparent in the actual metaphor he uses. Probability distributions can be viewed as two types: bounded and unbounded. A "normal" (or Gaussian) distribution is of the unbounded type; its range goes from "negative infinity" to "positive infinity". If a particular process can be shown to follow a normal distribution, then more chances / trials / events may lead to outcomes far out on the tails of the distribution, very far from the mean. But this is not synonymous with "if you roll the dice enough times, even the most unlikely things are guaranteed to happen." That statement is patently false, and the metaphor Tegmark uses is a testament to its inherent falsity. Worse still, this assumption undergirds much of in-vogue scientific theorizing. But I digress. Let's assume that "rolling the dice" refers to the commonplace six-sided fair die. Each side is uniquely numbered one through six. The probability of rolling any number (1-6) is 1/6. This probability distribution can be grouped under two types: it is uniform (the same probability exists for each and all possible outcomes), and it is bounded (there are parameters to the range of possible outcomes). For example, if you roll a single fair die as described above, you will never roll a seven, or a 13, or a 154. If you rolled one die per second for the next 500 billion years (assuming no friction or wear to the die), you still would never roll anything other than the six original numbers. Thus, by his own words, all things are not possible. This is not a pedantic point, but a foundational one. Despite this rather large flaw, Our Mathematical Universe is still worth reading. In fact, if I put my lit-crit hat on, and accept Wimsatt and Beardsley's assertion that one cannot know the author's intent, I could read this book as a work of theology. (I nevertheless do not believe that this is how Tegmark envisioned his work to be read, at least in this instance of the Level 4 multiverse). But the multiverse concept is still interesting, as are Tegmark's beliefs about the mathematical structure of all things. Each chapter ends with a section called "The Bottom Line" which condenses that section's ideas into a dozen or so bullets, and there is a good "Suggestions for Further Reading" in the back. Finally, Our Mathematical Universe has coerced me to create a new Goodreads shelf (need-to-read-again), and has already led to the purchase of four additional books, which (to me) is a very good thing. This book ties everything of the physical realm with the mathematical universe. The end result of his musing is a Level 4 Universe. The ideas are thought-provoking and not too easy to explicate, but higher math is not require do read the book. The book takes on the universe where the Level I and II universes pertains; next the quantum reality which is too small to be seen adequately and shows forth the Level III Universe; and then the mathematical reality of the Level IV universe. This is a mixed bag of a book. It gets a plus for a very good coverage of decoherence, and for its clear setting out of Hugh Everett's Many-Worlds interpretation of quantum mechanics. However... He's got a number of problems. An initial one is an argument that if there are an infinite number of universes (defined by locality) under Guth's inflation model, there must be universes which are, so to speak, identical to ours except for details like "what I had for breakfast this morning". A moment's thought will suggest that, as the type of infinity involved would be that of enumerable infinity (like the integers) as the result of a continuing set of discrete events, the conclusion does not follow. (There are an infinite number of odd numbers. This does not mean that all integers "close" to those in the set are in the set; rather the reverse.) There may be (probably are) constraints imposed by causality which winnow down the number of possibilities very firmly. (As long as one is dealing with infinite time and a finite set of fundamental particles, it's still true that eventually the same universe will recur, sometime around the time that random fluctuations of quantum particles in a single universe will regenerate the solar system even without multiple distinct universes.) It does manage, in combination with the weak Anthropic Principle, to handwave away the problem of the fine-tuning of basic values which haunts modern physics.To deal with the question of why there are basic values to set at all, Tegmark has to move well beyond Guth and into more problematic ground. By the end of the book, he's run into a bigger problem: he's essentially pushing a radical realist position, in the sense that the Scholastics used the term: mathematical systems, by being theoretically possible, must have a "real" existence. He does this without any actual background in the Realist/Nominalist fight (nor would it help him much, because the common ground of the Scholastics -- a First Cause which could be characterized as divine -- is not available to him). As explanatory mechanisms go this is fairly radically unsatisfactory: it merely turns the two questions of "Why did quantum fields exist in potentia as a context for the Big Bang?" and "Why is mathematics such an effective tool for understanding the universe?" into "Why should constructs built on top of abstract set theory (basically, when you get down to foundations, almost all of math is based on declaring relations between sets or characteristics of sets such as cardinality and then building on them) be more than pleasing patterns in the hominid brain?". Overall, an interesting read, but I suspect he's barking up the wrong tree. sem críticas | adicionar uma crítica
"Max Tegmark leads us on an astonishing journey through past, present, and future, and through the physics, astronomy and mathematics that are the foundation of his work, most particularly his hypothesis that our physical reality is a mathematical structure and his theory of the ultimate multiverse. In a dazzling combination of both popular and ground-breaking science, he not only helps us grasp his often mind-boggling theories (his website gives a flavor of how they might boggle the mind), but he also shares with us some of the often surprising triumphs and disappointments that have shaped his life as a scientist. Fascinating from first to last--here is a book for the full science-reading spectrum"-- Não foram encontradas descrições de bibliotecas. |
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Part two of the book is different though. After describing the state of science and research and the more or less hard "facts" (reasonably likely hypothesis) he runs into a more philosophical mode where ideas are more or less far-fetched. Possibly correct (who knows) but more or less unprovable so more like religion than science. This part is possibly interesting in some ways, but much less so than the first part. This is the part Tegmark likes though. For him the first part was to get the book published and read and this part is what he wanted to write. Unfortunately for many readers. Just short, it's about the universe being infinite and containing everything in infinite copies, which means that we exist in infinite copies, and some of the copies may even be in same spacetime as us, just in a different dimension.

The third, very small part, is about the future of mankind, and the scare for low-risk events like a nuclear war still destroying the planet we live on, or machine intelligence conquering the world. ( )