Existential physics A scientist's guide to life's biggest questions

Review by Booklist Review

Hossenfelder (Lost in Math, 2018) elegantly illustrates complex ideas in straightforward, lay-friendly language. A theoretical physicist based at the Frankfurt Institute for Advanced Studies, Hossenfelder takes readers on a riveting cerebral journey through surprisingly confounding differences between scientific method and storytelling. For example, many theories attempt to explain our universe's initial moment of creation. But are they fundamentally scientific or just dressed-up conjecture and stories with mathematics as support? When science and story are entangled in this way, how are we to make sense of our place in the universe? Hossenfelder responds to these queries with originality and new perspectives, addressing concepts of time (past, present, and future), universe origin stories, quantum mechanics, determinism, language, math, information, the predictability of knowledge, free will, consciousness, and much more. In addition to her own powerful voice, Hossenfelder includes enlightening interviews with David Deutsch, Roger Penrose, and Zeeya Merali, all luminaries in the field. Most chapters close with "The Brief Answer," which succinctly frames Hossenfelder's big ideas. Existential Physics is spectacular, and a must-read for all who ponder the purpose of existence.

From Booklist, Copyright (c) American Library Association. Used with permission.

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Review by Publisher's Weekly Review

Physicist Hossenfelder (Lost in Math) considers what "physics says about the human condition" in this smart survey. She uses the term "ascientific" for ideas that are beyond the reach of science--the "hypothesis of God," the existence of additional universes, the belief that subatomic particles are conscious--and explores fascinating questions about predictability ("Instead of worrying about simulating human brains, we should pay more attention to who gets to ask questions of artificial brains"), the meaning of life (passing on knowledge, as she sees it), and the existence of free will ("the future is determined by the past"), sometimes offering provocative conclusions: "It sounds crazy, but the idea that the past and future exist in the same way as the present is compatible with all we currently know." Readers will want to have a basic knowledge of physics before entering, and will be quickly convinced by Hossenfelder's case that the fact that "physics has something to say about our connection to the universe is not so surprising." And though she asserts that "physicists are really good at answering questions, but really bad at explaining why anyone should care," her curiosity and clever prose prove that doesn't have to be the case. Budding physics buffs, take note. (Aug.)

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Review by Library Journal Review

Physicist and self-described "general explainer" Hossenfelder (Lost in Math: How Beauty Leads Physics Astray) offers another excellent book on physics for general readers. She asks what people can learn about themselves through the current understanding of the fundamental laws of nature? What can physics tell one about consciousness, creation, and time? Hossenfelder uses current and historical research to show the deep connections between philosophy and the scientific method. She relates how physicists struggle with language and metaphor in sharing how quantum mechanics addresses big questions with wider audiences. She intersperses short chapters organized by topic with interviews of Nobel Prize winners, Royal Society members, popular science authors and science journalists who answer questions about both spiritual beliefs and scientific pursuits. She concludes with the applications of quantum mechanics to real-life problems such as weather forecasting, development of nuclear power, and regulation of economic systems. VERDICT Recommended for readers interested in philosophy of science and the sorts of questions that current science can and can't answer.--Catherine Lantz

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Review by Kirkus Book Review

A German physicist digs into a host of existential quandaries. In her 2018 book, Lost in Math: How Beauty Leads Physics Astray, Hossenfelder, research fellow at the Frankfurt Institute for Advanced Studies, excoriated her colleagues for falling in love with theories that bear little relation to reality. In her second book, she turns her gimlet eye on popular beliefs. More than other scientific fields, notes the author, physics asks profound questions about the meaning of everything, including life and death, the origin of the universe, and the nature of reality. Religious leaders ask the same questions, as do philosophers, gurus, mystics, alternative healers, and outright quacks. Unlike many other science writers, Hossenfelder is less interested in denouncing pseudoscience than revealing that many spiritual ideas are compatible with modern physics. Natural laws contradict others, and still others are "ascientific"--i.e., neither true nor false but unprovable: "Science has nothing to say about it. At least, science in its current state." Some fashionable beliefs are "more appealing the less you understand physics," but Hossenfelder avoids low-hanging fruit (Deepak Chopra and Elon Musk make fleeting appearances), preferring to interview and often argue with fellow physicists, including Nobel laureates. Casting her net widely, she investigates God and spirituality, free will, universal consciousness, dualism (whether the mind is separate from the body), the Big Bang theory about the origin of the cosmos, the possible existence of parallel universes, and whether we live in a computer simulation. As the author notes, the "simulation hypothesis" annoys her because it represents "a bold claim about the laws of nature that doesn't pay any attention to what we know about the laws of nature." Separating reality from nonsense has preoccupied philosophers for centuries. Nonsense remains as popular as ever, but readers who wonder how to tell a good from a bad explanation can now consult two good books: David Deutsch's The Beginning of Infinity and this one. An intriguing book fully of highly opinionated and convincing arguments. Copyright (c) Kirkus Reviews, used with permission.

Copyright (c) Kirkus Reviews, used with permission.

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Can I ask you something?" a young man inquired after learning that I am a physicist. "About quantum mechanics," he added, shyly. I was all ready to debate the measurement postulate and the pitfalls of multipartite entanglement, but I was not prepared for the question that followed: "A shaman told me that my grandmother is still alive. Because of quantum mechanics. She is just not alive here and now. Is this right?" As you can tell, I am still thinking about this. The brief answer is, it's not totally wrong. The long answer will follow in chapter 1, but before I get to the quantum mechanics of deceased grandmothers, I want to tell you why I'm writing this book. During more than a decade in public outreach, I noticed that phys-icists are really good at answering questions, but really bad at explain-ing why anyone should care about their answers. In some research areas, a study's purpose reveals itself, eventually, in a marketable product. But in the foundations of physics--where I do most of my research--the primary product is knowledge. And all too often, my colleagues and I present this knowledge in ways so abstract that no one understands why we looked for it in the first place. Not that this is specific to physics. The disconnect between experts and non-experts is so widespread that the sociologist Steve Fuller claims that academics use incomprehensible terminology to keep insights sparse and thereby more valuable. As the American journalist and Pulitzer Prize winner Nicholas Kristof complained, academics encode "insights into turgid prose" and "as a double protection against public consumption, this gobbledygook is then sometimes hidden in obscure journals." Case in point: People don't care much whether quantum mechanics is predictable; they want to know whether their own behavior is predictable. They don't care much whether black holes destroy information; they want to know what will happen to the collected infor- mation of human civilization. They don't care much whether galactic filaments resemble neuronal networks; they want to know if the universe can think. People are people. Who'd have thought? Of course, I want to know these things too. But somewhere along my path through academia I learned to avoid asking such questions, not to mention answering them. After all, I'm just a physicist. I'm not competent to speak about consciousness and human behavior and such. Nevertheless, the young man's question drove home to me that physicists do know some things, if not about consciousness itself, then about the physical laws that everything in the universe--including you and I and your grandmother--must respect. Not all ideas about life and death and the origin of human existence are compatible with the foundations of physics. That's knowledge we should not hide in obscure journals using incomprehensible prose. It's not just that this knowledge is worth sharing; keeping it to ourselves has consequences. If physicists don't step forward and explain what physics says about the human condition, others will jump at the opportunity and abuse our cryptic terminology for the promotion of pseudoscience. It's not a coincidence that quantum entanglement and vacuum energy are go-to explanations of alternative healers, spiritual media, and snake oil sellers. Unless you have a PhD in physics, it'shard to tell our gobbledygook from any other. However, my aim here is not merely to expose pseudoscience forwhat it is. I also want to convey that some spiritual ideas are perfectlycompatible with modern physics, and others are, indeed, supportedby it. And why not? That physics has something to say about our connectionto the universe is not so surprising. Science and religion havethe same roots, and still today they tackle some of the same questions:Where do we come from? Where do we go to? How much can we know? When it comes to these questions, physicists have learned a lot in the past century. Their progress makes clear that the limits of scienceare not fixed; they move as we learn more about the world. Correspondingly, some belief-based explanations that once aided sensemaking and gave comfort we now know to be just wrong. The idea, for example, that certain objects are alive because they are endowed with a special substance (Henri Bergson's "élan vital") was entirely compatible with scientific fact two hundred years ago. But it no longer is. In the foundations of physics today, we deal with the laws of nature that operate on the most fundamental level. Here, too, the knowledge we gained in the past hundred years is now replacing old, belief-based explanations. One of these old explanations is the idea that consciousness requires something more than the interaction of many particles, some kind of magic fairy dust, basically, that endows certain objects with special properties. Like the élan vital, this is an outdated and useless idea that explains nothing. I will get to this in chapter 4, and in chapter 6 I'll discuss the consequences this has for the existence of free will. Another idea ready for retirement is the belief that our universeis especially suited to the presence of life, the focus of chapter 7. However, demarcating the current limits of science doesn't onlydestroy illusions; it also helps us recognize which beliefs are still compatible with scientific fact. Such beliefs should maybe not be called unscientific but rather ascientific, as Tim Palmer (whom we'll meet later) aptly remarked: science says nothing about them. One such belief is the origin of our universe. Not only can we not currently explain it, but also it is questionable whether we will ever be able to explain it. It may be one of the ways that science is fundamentally limited. At least that's what I currently believe. The idea that the universe itself is conscious, I have found to my own surprise, is difficult to rule out entirely (chapter 8). And the jury is still out on whether or not human behavior is predictable (chapter 9). In brief, this is a book about the big questions that modern physics raises, from the question whether the present moment differs from the past, to the idea that each elementary particle may contain a universe, to the worry that the laws of nature determine our decisions. I cannot, of course, offer final answers. But I want to tell you how much scientists currently know, and also where science crosses over into mere speculation. I will mostly stick with established theories of nature that are backed up by evidence. All of what I am going to say, therefore, should come with the preamble "as far as we currently know," meaning that further scientific progress might lead to revision. In some cases, the answer to a question depends on properties of natural laws that we do not yet fully understand, like quantum measurements or the nature of space-time singularities. If so, I will point out how future research could help answer the question. Because I don't want you to hear just my own opinion, I have added a few interviews. And at the end of the book, you'll find a brief glossary with definitions of the most impor- tant technical terms. Terms in the glossary are marked bold when they first appear in the text hereafter. Existential Physics is for those who have not forgotten to ask the big questions and are not afraid of the answers. Excerpted from Existential Physics: A Scientist's Guide to Life's Biggest Questions by Sabine Hossenfelder All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.

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