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A physicist is an attempt by an atom to understand itself.
Michio Kaku, an American theoretical physicist, a futurist, and popularizer of science, Parallel Worlds: A Journey Through Creation, Higher Dimensions, and the Future of the Cosmos, Doubleday, 2004.

Marcelo Gleiser: Life is fundamentally asymmetric

“Look into a mirror and you’ll simultaneously see the familiar and the alien: an image of you, but with left and right reversed. Left-right inequality has significance far beyond that of mirror images, touching on the heart of existence itself. From subatomic physics to life, nature prefers asymmetry to symmetry. (…) Life is fundamentally asymmetric. (…)

Somehow, during its infancy, the cosmos selected matter over antimatter. This imperfection is the single most important factor dictating our existence. (…) It is not symmetry and perfection that should be our guiding principle, as it has been for millennia. (…)

The science we create is just that, our creation. Wonderful as it is, it is always limited, it is always constrained by what we know of the world. […] The notion that there is a well-defined hypermathematical structure that determines all there is in the cosmos is a Platonic delusion with no relationship to physical reality. (…)

The critics of this idea miss the fact that a meaningless cosmos that produced humans (and possibly other intelligences) will never be meaningless to them (or to the other intelligences). To exist in a purposeless Universe is even more meaningful than to exist as the result of some kind of mysterious cosmic plan. Why? Because it elevates the emergence of life and mind to a rare event, as opposed to a ubiquitous and premeditated one. (…)

Unified theories, life principles, and self-aware universes are all expressions of our need to find a connection between who we are and the world we live in. I do not question the extreme importance of understanding the connection between man and the cosmos. But I do question that it has to derive from unifying principles. (…)

For a clever fish, water is “just right“ for it to swim in. Had it been too cold, it would freeze; too hot, it would boil. Surely the water temperature had to be just right for the fish to exist. “I’m very important. My existence cannot be an accident,” the proud fish would conclude. Well, he is not very important. He is just a clever fish. The ocean temperature is not being controlled with the purpose of making it possible for it to exist. Quite the opposite: the fish is fragile. A sudden or gradual temperature swing would kill it, as any trout fisherman knows. We so crave for meaningful connections that we see them even when they are not there. (…) The gravest mistake we can make is to think that the cosmos has plans for us, that we are somehow special from a cosmic perspective.”
Marcelo Gleiser is the Appleton Professor of Natural Philosophy at Dartmouth College, ☞ ‘Elegance,’ ‘Symmetry,’ and ‘Unity’: Is Scientific Truth Always Beautiful?, Lapidarium notes (Image courtesy of Ben Lansky)
" "Either way, it would mean that the Universe is fundamentally nonlocal, in the sense that every bit of the Universe can be connected to any other bit anywhere, instantly. That such connections are possible defies our everyday intuition and represents another extreme solution, but arguably preferable to faster-than-light communication. “Our result gives weight to the idea that quantum correlations somehow arise from outside spacetime, in the sense that no story in space and time can describe them.” “
“The essence of quantum physics is unpredictability. At every instant, the objects in our physical environment—the atoms in our lungs and the light in our eyes—are making unpredictable choices, deciding what to do next. According to Everett and Deutsch, the multiverse contains a universe for every combination of choices. There are so many universes that every possible sequence of choices occurs in at least one of them. Each universe is constantly splitting into many alternative universes, and the alternatives are recombining when they arrive at the same final state by different routes. The multiverse is a huge network of possible histories diverging and reconverging as time goes on. The “quantum weirdness” that we observe in the behavior of atoms, the “spooky action at a distance” that Einstein famously disliked, is the result of universes recombining in unexpected ways.

According to Deutsch, each of us exists in the multiverse as a crowd of almost identical creatures, traveling together through time along closely related histories, splitting and recombining constantly like the atoms of which we are composed. He does not claim to have an answer to the question “Why does the multiverse exist?” or to the easier question “What is the nature of consciousness?” He sees ahead of us a long future of slow exploration, answering philosophical questions that we do not yet know how to ask. One of the questions that we know how to ask but not to answer is: “Does quantum computing play an essential role in our consciousness?” For Deutsch, the physics of quantum computing is the most promising clue that may lead us to a deeper understanding of our existence. He theorizes, Holt tells us, that “all the different parallel universes in the multiverse” could “be coaxed into collaborating on a single computation.
Freeman Dyson, a British-born American theoretical physicist and mathematician, famous for his work in quantum electrodynamics, solid-state physics, astronomy and nuclear engineering, What Can You Really Know?, The New York Review of Books, Nov 10, 2011.

“The idea that we can systematically understand certain aspects of the world and make predictions based on what we’ve learned — while appreciating and categorizing the extent and limitations of what we know — plays a big role in how we think. Many words that summarize the nature of science such as “cause and effect,” “predictions,” and ” experiments,” as well as words that describe probabilistic results such as “mean,” “median,” “standard deviation,” and the notion of “probability” itself help us understand more specifically what this means and how to interpret the world and behavior within it.

Effective theory" is one of the more important notions within and outside of science. The idea is to determine what you can actually measure and decide — given the precision and accuracy of your measuring tools — and to find a theory appropriate to those measurable quantities. The theory that works might not be the ultimate truth—but it’s as close an approximation to the truth as you need and is also the limit to what you can test at any given time. People can reasonably disagree on what lies beyond the effective theory, but in a domain where we have tested and confirmed it, we understand the theory to the degree that it’s been tested.

An example is Newton’s Laws, which work as well as we will ever need when they describe what happens to a ball when we throw it. Even though we now know quantum mechanics is ultimately at play, it has no visible consequences on the trajectory of the ball. Newton’s Laws are part of an effective theory that is ultimately subsumed into quantum mechanics. Yet Newton’s Laws remain practical and true in their domain of validity. It’s similar to the logic you apply when you look at a map. You decide the scale appropriate to your journey — are you traveling across the country, going upstate, or looking for the nearest grocery store — and use the map scale appropriate to your question.

Terms that refer to specific scientific results can be efficient at times but they can also be misleading when taken out of context and not supported by true scientific investigation. But the scientific methods for seeking, testing, and identifying answers and understanding the limitations of what we have investigated will always be reliable ways of acquiring knowledge. A better understanding of the robustness and limitations of what science establishes, as well as probabilistic results and predictions, could make the world a better place.”

See also:

Lisa Randall, Dangling Particles, Edge, Sep 18, 2005.
Lisa Randall, Theories Of The Brane: Lisa Randall, Edge, Sep 2, 2003.
S. Hawking, L. Mlodinow on why is there something rather than nothing and why are the fundamental laws as we have described them, Lapidarium notes
Lisa Randall, American theoretical physicist and a leading expert on particle physics and cosmology, Science, Edge, 2012. (Illustration from S. Hawking, The Grand Design, Random House, 2010).
According to the idea of model-dependent realism, our brains interpret the input from our sensory organs by making a model of the outside world. We form mental concepts of our home, trees, other people, the electricity that flows from wall sockets, atoms, molecules, and other universes. These mental concepts are the only reality we can know. There is no modelindependent test of reality. It follows that a well-constructed model creates a reality of its own.
The naive view of reality is not compatible with modern physics. To deal with such paradoxes we shall adopt an approach that we call model-dependent realism. It is based on the idea that our brains interpret the input from our sensory organs by making a model of the world. When such a model is successful at explaining events, we tend to attribute to it, and to the elements and concepts that constitute it, the quality of reality or absolute truth. But there may be different ways in which one could model the same physical situation, with each employing different fundamental elements and concepts. If two such physical theories or models accurately predict the same events, one cannot be said to be more real than the other; rather, we are free to use whichever model is most convenient.
Stephen Hawking, British theoretical physicist, cosmologist, and author and Leonard Mlodinow, physicist and author, The Grand Design, Bantam Books, New York, 2010.
According to inflation, the more than 100 billion galaxies, sparkling throughout space like heavenly diamonds, are nothing but quantum mechanics writ large across the sky. To me, this realization is one of the greatest wonders of the modern scientific age.
Brian Greene, American theoretical physicist and string theorist, The Fabric of the Cosmos: Space, Time, and the Texture of Reality, Alfred A. Knopf, 2004.
Now, why should the universe be constructed in such a way that atoms acquire the ability to be curious about themselves?
Marcus Chown, award-winning writer, journalist and broadcaster, currently cosmology consultant for New Scientist magazine, The Magic Furnace: The Search for the Origins of Atoms, Oxford University Press, 2001
Nature may reach the same result in many ways. Like a wave in the physical world, in the infinite ocean of the medium which pervades all, so in the world of organisms, in life, an impulse started proceeds onward, at times, may be, with the speed of light, at times, again, so slowly that for ages and ages it seems to stay, passing through processes of a complexity inconceivable to men, but in all its forms, in all its stages, its energy ever and ever integrally present.

A single ray of light from a distant star falling upon the eye of a tyrant in bygone times may have altered the course of his life, may have changed the destiny of nations, may have transformed the surface of the globe, so intricate, so inconceivably complex are the processes in Nature. In no way can we get such an overwhelming idea of the grandeur of Nature than when we consider, that in accordance with the law of the conservation of energy, throughout the Infinite, the forces are in a perfect balance, and hence the energy of a single thought may determine the motion of a universe.
Nikola Tesla, Serbian-American inventor, mechanical and electrical engineer. He was an important contributor to the birth of commercial electricity (1856-1943), The inventions, researches and writings of Nikola Tesla, Barnes & Noble, 1992, p. 298.
Our children no longer want to become physicists and astronauts. They want to invent the next Facebook instead. Short of that, they are happy to land a job at Google. They don’t talk quanta — they dream bits. They don’t see entanglement but recognize with ease nodes and links. As complexity takes a driving seat in science, engineering and business, we physicists cannot afford to sit on the sidelines.
Albert-László Barabási, physicist, Professor and Director of Northeastern University’s Center for Complex Network Research (CCNR), The network takeover (pdf), Nature Physics, Vol 8, Jan 2012.
Brian Greene: Our Universe May Be a Giant Hologram

Plato likened our view of the world to that of an ancient forebear watching shadows meander across a dimly lit cave wall. He imagined our perceptions to be but a faint inkling of a far richer reality that flickers beyond reach.

Two millennia later, Plato’s cave may be more than a metaphor. To turn his suggestion on its head, reality—not its mere shadow—may take place on a distant boundary surface, while everything we witness in the three common spatial dimensions is a projection of that faraway unfolding. Reality, that is, may be akin to a hologram. Or, really, a holographic movie.” “
Brian Greene, American theoretical physicist and string theorist. He has been a professor at Columbia University since 1996, Our Universe May Be a Giant Hologram, Aug 4, 2011, Excerpted from The Hidden RealityKnopf, 2011. (tnx johnsparker)
It turns out that an eerie type of chaos can lurk just behind a facade of order - and yet, deep inside the chaos lurks an even eerier type of order.
Douglas R. Hofstadter, American academic whose research focuses on consciousness, analogy-making, discovery in mathematics and physics, Metamagical Themas: Questing for the Essence of Mind and Pattern, Basic Books, 1985
Why we think like quarks: ‘To be human is to be quantum’

“People aren’t logical, at least by classical standards. But quantum theory, Aerts argues, offers richer logical possibilities. (…) “Quantum probabilities have the potential to provide a better framework for modelling human decision making.” (…) “The structure of human conceptual knowledge is quantum-like because context plays a fundamental role.” (…)

Why should quantum logic fit human behaviour? The reason is to do with our finite brain being overwhelmed by the complexity of the environment yet having to take action long before it can calculate its way to the certainty demanded by classical logic. Quantum logic may be more suitable to making decisions that work well enough, even if they’re not logically faultless. “The constraints we face are often the natural enemy of getting completely accurate and justified answers.” (…)

This idea fits with the views of some psychologists, who argue that strict classical logic only plays a small part in the human mind. (…) Much of our thinking operates on a largely unconscious level, where thought follows a less restrictive logic and forms loose associations between concepts. (…)

This is not to say that the human brain or consciousness have anything to do with quantum physics, only that the mathematical language of quantum theory happens to match the description of human decision-making. (…) To be human is to be quantum.” “
Mark Buchanan, American physicist and author, ☞ Quantum minds: Why we think like quarks - ‘To be human is to be quantum’, New Scientist, 05 September 2011
Where Is Now? The Paradox Of The Present: ‘[it] exists at the fractured center of many overlapping pasts’

“The night sky is a time machine. (…) The sky we see at any moment defines not a single past but multiple overlapping pasts of different depths. The star’s image from 100 years ago and the galaxy image from 100 million years ago reach us at the same time. All of those “thens” define the same “now” for us. (…)

The simple truth is that every aspect of our personal “now” is a layered impression of a world already lost to the past. (…)

All we know about the world comes to us via signals: light waves, sound waves and electrical impulses running along our nerves. These signals move at a finite speed. It always takes some finite amount of time for the signal to travel from the world to your body’s sensors (and on to your brain). (…)

Signal travel time constitutes a delay and all those overlapping delays constitute an essential separation. The inner world of your experience is, in a temporal sense, cut off from the outer world you inhabit. (…) We live, each of us, trapped in our own now. (…)

According to Presentism only the present moment has ontological validity. In other words: only the present truly exists; only the present is real.” (…)

You never experience the world as it is. You only experience it in the way light brings it to you. (…) A simple truth about our experience of the world. We have no “direct” knowledge of the world-in-of-itself but, instead, are forced to rely on signals carried to us from external objects. If the properties of the signals are somehow changed while they are traveling to us then our experience of the world is changed as well.” “
Adam Frank, US physicist, astronomer and writer, Department of Physics And Astronomy at University of Rochester,☞ Where Is Now? The Paradox Of The Present