The Fabric of the Cosmos: Space, Time, and the Texture of Reality
by Brian Greene
30 popular highlights from this book
Key Insights & Memorable Quotes
Below are the most popular and impactful highlights and quotes from The Fabric of the Cosmos: Space, Time, and the Texture of Reality:
“Cosmology is among the oldest subjects to captivate our species. And it’s no wonder. We’re storytellers, and what could be more grand than the story of creation?”
“Understanding requires insight. Insight must be anchored.”
“Physicists have come to realize that mathematics, when used with sufficient care, is a proven pathway to truth.”
“You should never be surprised by or feel the need to explain why any physical system is in a high entropy state.”
“But, as Einstein once said, “For we convinced physicists, the distinction between past, present, and future is only an illusion, however persistent.”5”
“There is but one truly philosophical problem, and that is suicide,” the text began. I winced. “Whether or not the world has three dimensions or the mind nine or twelve categories,” it continued, “comes afterward”; such questions, the text explained, were part of the game humanity played, but they deserved attention only after the one true issue had been settled. The book was The Myth of Sisyphus and was written by the Algerian-born philosopher and Nobel laureate Albert Camus. After a moment, the iciness of his words melted under the light of comprehension. Yes, of course, I thought. You can ponder this or analyze that till the cows come home, but the real question is whether all your ponderings and analyses will convince you that life is worth living. That’s what it all comes down to. Everything else is detail.”
“The world of the everyday suddenly seemed nothing but an inverted magic act, lulling its audience into believing in the usual, familiar conceptions of space and time, while the astonishing truth of quantum reality lay carefully guarded by nature's sleights of hand.”
“And since, according to the big bang theory, the bang is what is supposed to have happened at the beginning, the big bang leaves out the bang. It tells us nothing about what banged, why it banged, how it banged, or, frankly, whether it ever really banged at all.”
“Quantum mechanics challenges this view by revealing, at least in certain circumstances, a capacity to transcend space; long-range quantum connections can bypass spatial separation. Two objects can be far apart in space, but as far as quantum mechanics is concerned, it’s as if they’re a single entity.”
“A mecânica quântica é implacavelmente eficiente; explica aquilo que vemos, mas impede-vos de ver a explicação.”
“Because of quantum uncertainty, empty space is teeming with quantum activity.”
“The overarching lesson that has emerged from scientific inquiry over the last century is that human experience is often a misleading guide to the true nature of reality.”
“Whereas classical physics describes the present as having a unique past, the probability waves of quantum mechanics enlarge the arena of history: in Feynman’s formulation, the observed present represents an amalgam—a particular kind of average— of all possible pasts compatible with what we now see...How come there is no evidence in day-to-day life of the strange way in which the past apparently unfolds into the present? The reason, discussed briefly in Chapter 4 and to be elaborated shortly with greater precision, is that baseballs, planets, and comets are comparatively large, at least when compared with particles like electrons. And in quantum mechanics, the larger something is, the more skewed the averaging becomes: All possible trajectories do contribute to the motion of a baseball in flight, but the usual path—the one single path predicted by Newton’s laws—contributes much more than do all other paths combined. For large objects, it turns out that classical paths are, by an enormous amount, the dominant contribution to the averaging process and so they are the ones we are familiar with. But when objects are small, like electrons, quarks, and photons, many different histories contribute at roughly the same level and hence all play important parts in the averaging process.”
“Although it may not be immediately apparent, we have now come to an intriguing point. The second law of thermodynamics seems to have given us an arrow of time, one that emerges when physical systems have a large number of constituents. “For things with many constituents, going from lower to higher entropy—from order to disorder—is easy, so it happens all the time. Going from higher to lower entropy—from disorder to order—is harder, so it happens rarely, at best.”
“Quantum mechanics breaks with this tradition. We can’t ever know the exact location and exact velocity of even a single particle. We can’t predict with total certainty the outcome of even the simplest of experiments, let alone the evolution of the entire cosmos... Nevertheless, these results, coming from both theoretical and experimental considerations, strongly support the conclusion that the universe admits interconnections that are not local. Something that happens over here can be entwined with something that happens over there even if nothing travels from here to there—and even if there isn’t enough time for anything, even light, to travel between the events. This means that space cannot be thought of as it once was: intervening space, regardless of how much there is, does not ensure that two objects are separate, since quantum mechanics allows an entanglement, a kind of connection, to exist between them.”
“If superstring theory is proven correct, we will be forced to accept that the reality we have known is but a delicate chiffon draped over a thick and richly textured cosmic fabric.”
“But according to the quantum laws, even if you make the most perfect measurements possible of how things are today, the best you can ever hope to do is predict the probability that things will be one way or another at some chosen time in the future, or that things were one way or another at some chosen time in the past. The universe, according to quantum mechanics, is not etched into the present; the universe, according to quantum mechanics, participates in a game of chance... Things become definite only when a suitable observation forces them to relinquish quantum possibilities and settle on a specific outcome.”
“The implications of these features of quantum mechanics for our picture of reality are a subject of ongoing research. Many scientists, myself included, view them as part of a radical quantum updating of the meaning and properties of space.”
“At the ultramicroscopic level, the universe would be akin to a string symphony vibrating matter into existence.”
“I expect that regardless of where the search for the foundations of space and time may take us, regardless of modifications to string/M-theory that may be waiting for us around the bend, holography will continue to be a guiding concept.”
“It doesn’t seem that something on a hard-to-locate boundary is somehow calling the shots regarding what happens here in the bulk.”
“the startling idea that the comings and goings we observe in the three dimensions of day-to-day life might themselves be holographic projections of physical processes taking place on a distant, two-dimensional surface.”
“An informed appraisal of life absolutely require(s) a full understanding of life’s arena–the universe. … By deepening our understanding of the true nature of physical reality, we profoundly reconfigure our sense of ourselves and our experience of the universe.”
“Remember from Chapter 7 that in the Many Worlds framework, every potential outcome embodied in a quantum wavefunction—a particle’s spinning this way or that, another particle’s being here or there—is realized in its own separate, parallel universe. The universe we’re aware of at any given moment is but one of an infinite number in which every possible evolution allowed by quantum physics is separately realized.”
“If free will is an illusion, and if time travel to the past is possible, then your inability to prevent your parents from meeting poses no puzzle. Although you feel as if you have control over your actions, the laws of physics are really pulling the strings.”
“if you know the quantum wavefunction right now for every particle in the universe, Schrödinger’s equation tells you how the wavefunction was or will be at any other moment you specify. This”
“The equations are indifferent to the supposed freedom of human will. Some have taken this to mean that in a classical universe, free will would be an illusion. You are made of a collection of particles, so if the laws of classical physics could determine everything about your particles at any moment—where they’d be, how they’d be moving and so on—your willful ability to determine your own actions would appear fully compromised.”
“If you time-travel to the past, you can’t change it any more than you can change the value of pi. If you travel to the past, you are, will be, and always were part of the past, the very same past that leads to your traveling to it.”
“all events making up the history of the universe are on view; they are all there, static and unchanging. Different observers don’t agree on which of the events happen at the same time—they time-slice the spacetime loaf at different angles—but the total loaf and its constituent events are universal, literally.”
“Each moment—each event or happening—exists, just as each point in space exists. Moments don’t momentarily come to life when illuminated by the “spotlight” of an observer’s present; that image aligns well with our intuition but fails to stand up to logical analysis. Instead, once illuminated, always illuminated. Moments don’t change. Moments are. Being illuminated is simply one of the many unchanging features that constitute a moment.”
