UNIVERSE

Layers Of Reality

Sean Carroll
[5.28.15]

We know there's a law of nature—the second law of thermodynamics—that says that disorderliness grows with time. Is there another law of nature that governs the complexity of what happens? That talks about multiple layers of the structures and how they interact with each other? Embarrassingly enough, we don't even know how to define this problem yet. We don't know the right quantitative description for complexity. This is very early days. This is Copernicus, not even Kepler, much less Galileo or Newton. This is guessing at the ways to think about these problems.

SEAN CARROLL is a research professor at Caltech and the author of The Particle at the End of the Universe, which won the 2013 Royal Society Winton Prize, and From Eternity to Here: The Quest for the Ultimate Theory of Time. He has recently been awarded a Guggenheim Fellowship, the Gemant Award from the American Institute of Physics, and the Emperor Has No Clothes Award from the Freedom From Religion Foundation. Sean Carroll's Edge Bio Page

Formulating Science in Terms of Possible and Impossible Tasks

Chiara Marletto
[12.6.14]

It turns out that in the constructor theoretic view, humans, as knowledge creating systems, are quite central to fundamental physics in an objective, non-anthropocentric, way. This is a very deep change in perspective. One of the ideas that will be dropped if constructor theory turns out to be effective is that the only fundamental entities in physics are laws of motion and initial conditions. In order for physics to accommodate more of physical reality, there needs to be a switch to this new mode of explanation, which accepts that scientific explanation is more than just predictions. Predictions will be supplemented with statements about what tasks are possible, what are impossible and why.

CHIARA MARLETTO is a Junior Research Fellow at Wolfson College and Postdoctoral Research Assistant at the Materials Department, University of Oxford; Currently working with David Deutsch. Chiara Marletto's Edge Bio Page

THE REALITY CLUB: NEW Arnold Trehub


FORMULATING SCIENCE IN TERMS OF POSSIBLE AND IMPOSSIBLE TASKS 

I’ve been thinking about constructor theory a lot in the past few years. Constructor theory is this theory that David Deutsch proposed—a proposal for a new fundamental theory to formulate science in a completely different way from the prevailing conception of fundamental physics. It has the potential to change the way we formulate science because it’s a new mode of explanation.

When you think about physics, you usually describe things in terms of initial conditions and laws of motion; so what you say is, for example, where a comet goes given that it started in a certain place and time. In constructor theory, what you say is what transformations are possible, what are impossible, and why. The idea is that you can formulate the whole of fundamental physics this way; so, not only do you say where the comet goes, you say where it can go. This incorporates a lot more than what it is possible to incorporate now in fundamental physics.

Formulating Science in Terms of Possible and Impossible Tasks

Topic: 

  • UNIVERSE
http://vimeo.com/111429354

It turns out that in the constructor theoretic view, humans, or knowledge creating systems, are quite central to fundamental physics in an objective way and not an anthropocentric way. This is a very deep change in perspective. One of the ideas that will be dropped if constructor theory turns out to be effective is that the only fundamental entities in physics are laws of motion and initial conditions.

Chiara Marletto on Extinction

Chiara Marletto
[11.6.14]

 

There is a new fundamental theory of physics that’s called constructor theory, and was proposed by David Deutsch who pioneered the theory of the universe of quantum computer. David and I are working this theory together. The fundamental idea in this theory is that we formulate all laws of physics in terms of what tasks are possible, what are impossible, and why. In this theory we have an exact physical characterization of an object that has those properties, and we call that knowledge. Note that knowledge here means knowledge without knowing the subject, as in the theory of knowledge of the philosopher, Karl Popper.

 

We’ve just come to the conclusion that the fact that extinction is possible means that knowledge can be instantiated in our physical world. In fact, extinction is the very process by which that knowledge is disabled in its ability to remain instantiated in physical systems because there are problems that it cannot solve. With any luck that bit of knowledge can be replaced with a better one. 

 
[8:57]

CHIARA MARLETTO is a Junior Research Fellow at Wolfson College and Postdoctoral Research Assistant at the Materials Department, University of Oxford.  Chiara Marletto's Edge Bio Page


MOLLY CROCKETT: I’m pleased to welcome our second speaker, Chiara Marletto. She’s a quantum physicist working at the University of Oxford. She’s a bit of a polymath. She’s dabbled in Italian literature, engineering science, and quantum computation. Currently, she’s working with David Deutsch on constructor theory, which is a new fundamental theory of physics, and this touches on ideas that have been traditionally regarded as highly emergent and derivative, so for example, information, human knowledge, and the nature of life. Let’s welcome Chiara to the stage.

What's New In The Universe

Direct Evidence Of Cosmic Inflation
Alan Guth, Andrei Linde
[3.17.14]

 

Alan Guth, a charter member of the Reality Club, came to New York in 1980, to give one of the first Reality Club talks. He presented his new theory on the early universe, which he had been working on for the past couple of years and had described earlier that year in a paper titled "The Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems." It was a revolution in our understanding of the universe—a new theory that filled in the blanks left by earlier versions of the Big Bang theory. A few years later, Andrei Linde developed a version of Guth’s theory he refers to as Eternal Chaotic Inflation, which is now the most popular version of inflation.

Some thirty years later, I'm sitting in a hotel in Vancouver reading the news about what might turn out to be the most important scientific discovery of my lifetime: a possible direct confirmation of Guth's ideas. Using a radio telescope at the South Pole, John M. Kovac and his team of astronomers were able to glimpse the very early universe—capturing traces of light from 13.8 billion years ago. If their data are accurate, Guth was right.

Edge contributor and New York Times deputy science editor Dennis Overbye wrote about the developments in a story on the front page of Tuesday's New York Times: "...Inflation has been the workhorse of cosmology for 35 years, though many, including Dr. Guth, wondered whether it could ever be proved. ... If corroborated, Dr. Kovac’s work will stand as a landmark in science comparable to the recent discovery of dark energy pushing the universe apart, or of the Big Bang itself. It would open vast realms of time and space and energy to science and speculation."

How important is this development? MIT cosmologist Max Tegmark is quoted by Overbye as saying, "I think that if this stays true, it will go down as one of the greatest discoveries in the history of science." According to mathematical physicist Brian Greene, "If the results stand, they are a landmark discovery." Physicist Lawrence Krauss of Arizona State University, in a post on newyorker.com, wrote, "At rare moments in scientific history, a new window on the universe opens up that changes everything. Today was quite possibly such a day."

But nothing is more prescient than Guth's own talks from two Edge Eastover Farm events, in 2001 ("A Golden Age of Cosmology") and 2002 ("The Inflationary Universe"), and Linde's Edge interview in 2012 ("A Balloon Producing Balloons, Producing Balloons: a Big Fractal"). Continue below for EdgeVideo and texts.

John Brockman

FREE WILL, DETERMINISM, QUANTUM THEORY AND STATISTICAL FLUCTUATIONS: A PHYSICIST'S TAKE

Carlo Rovelli
[7.8.13]

Any attempt to link this discussion to moral, ethical or legal issues, as is often been done, is pure nonsense. The fact that it is possible to say that a criminal has been driven to kill because of the ways in which Newton's laws have acted on the molecules of his body has nothing to do either with the opportunity of punishment, nor with the moral condemnation. It is respecting those same laws by Newton that putting criminals in jail reduces the murders, and it is respecting those same laws by Newton that society as a whole functions, including its moral structure, which in turn determines behavior.  There is no contradiction between saying that a stone flew into the sky because a force pushed it, or because a volcano exploded.  In the same manner, there is no contradiction in saying we do not commit murder because something is encoded in the decision-making structure of our brain or because we are bound by a moral belief.

Free will has nothing to do with quantum mechanics. We are deeply unpredictable beings, like most macroscopic systems. There is no incompatibility between free will and microscopic determinism.  The significance of free will is that behavior is not determined by external constraints, not by the psychological description of our neural states to which we access. The idea that free will may have to do with the ability to make different choices on equal internal states is an absurdity, as the ideal experiment I have described above shows. The issue has no bearing on questions of a moral or legal nature. Our idea of being free is correct, but it is just a way to say that we are ignorant on why we make choices.

CARLO ROVELLI is a theoretical physicist, working on quantum gravity and on foundations of spacetime physics. He is Professor of Physics at Centre De Physique Théorique De Luminy at Aix-Marseille University, France and member of the Intitut Universitaire de France. He is the author of The First Scientist: Anaximander and His Legacy; and Quantum Gravity. 

Carlo Rovelli's Edge Bio Page

THE REALITY CLUB: Lee Smolin

A PHYSICIST LOOKS AT FREE WILL, DETERMINISM, QUANTUM THEORY AND STATISTICAL FLUCTUATIONS

Since Democritus suggested that the world can be seen as the result of accidental clashing of atoms, the question of free will has disturbed the sleeps of the naturalist: how to reconcile the deterministic dynamics of the atoms with man's freedom to choose? Modern physics has altered the data a bit, and the ensuing confusion requires clarification. 

Democritus assumed the movement of atoms to be deterministic: a different future does not happen without a different present. But Epicurus, who in physical matters was a close follower of Democritus, had already perceived a difficulty between this tight determinism and human freedom, and modified the physics of Democritus, introducing an element of indeterminism at the atomic level.

The new element was called "clinamen." The "clinamen" is a minimum deviation of an atom from its natural rectilinear path, which takes place in a completely random fashion. Lucretius, who presents the Democritean-Epicurean theory in his poem, "De Rerum Natura", "On Things Of Nature," notes in poetic words: the deviation from straight motion happens "uncertain tempore ... incertisque loci ", in an uncertain time and an uncertain place [Liber II, 218].

A very similar oscillation between determinism and indeterminism has happened again in modern physics. Newton's atomism is deterministic in a similar manner as Democritus's.  But at the beginning of the twentieth century, Newton's equations have been replaced by those of quantum theory, which bring back an element of indeterminism, quite similar, in fact, to Epicurus's correction of Democritus's determinism. At the atomic scale, the motion of the elementary particles is not strictly deterministic.

Can there be a relationship between this atomic-scale quantum indeterminism and human freedom to choose?

THINK ABOUT NATURE

Lee Smolin
[5.14.13]

Feynman once told me, "Whatever you do—you're going to have to do crazy things to think about quantum gravity—but whatever you do, think about nature. If you think about the properties of a mathematical equation, you're doing mathematics and you're not going to get back to nature. Whatever you do, have a question that an experiment could resolve at the front of your thinking." So I always try to do that.

 


TIME REBORN:
From the Crisis in Physics
to the Future of the Universe

 

LEE SMOLIN is a founding and senior faculty member at Perimeter Institute for Theoretical Physics in Waterloo, Canada. He is also Adjunct Professor of Physics at the University of Waterloo and is a member of the graduate faculty of the Department of Philosophy of the University of Toronto. He is the author of Time Reborn: From the Crisis in Physics to the Future of the Universe. Lee Smolin's Edge Bio Page

 


[58:16 minutes]

THE REALITY CLUB: Arnold Trehub, Sean Carroll, Lee Smolin, Bruce SterlingArnold Trehub, Amanda Gefter

 


THINK ABOUT NATURE

The main question I'm asking myself, the question that puts everything together, is how to do cosmology; how to make a theory of the universe as a whole system. This is said to be the golden age of cosmology and it is from an observational point of view, but from a theoretical point of view it's almost a disaster. It's crazy the kind of ideas that we find ourselves thinking about. And I find myself wanting to go back to basics—to basic ideas and basic principles—and understand how we describe the world in a physical theory.

What's the role of mathematics? Why does mathematics come into physics? What's the nature of time? These two things are very related since mathematical description is supposed to be outside of time. And I've come to a long evolution since the late 80's to a position, which is quite different from the ones that I had originally, and quite surprising even to me. But let me get to it bit by bit. Let me build up the questions and the problems that arise.

One way to start is what I call "physics in a box" or, theories of small isolated systems. The way we've learned to do this is to make an accounting or an itinerary—a listing of the possible states of a system. How can a possible system be? What are the possible configurations? What were the possible states? If it's a glass of Coca Cola, what are the possible positions and states of all the atoms in the glass? Once we know that, we ask, how do the states change? And the metaphor here—which comes from atomism that comes from Democritus and Lucretius—is that physics is nothing but atoms moving in a void and the atoms never change. The atoms have properties like mass and charge that never change in time. The void—which is space in the old days never changed in time—was fixed and they moved according to laws, which were originally given by or tried to be given by Descartes and Galileo, given by Newton much more successfully.

THINK ABOUT NATURE

Topic: 

  • UNIVERSE
https://vimeo.com/82413843

Feynman once told me, "Whatever you do—you're going to have to do crazy things to think about quantum gravity—but whatever you do, think about nature. If you think about the properties of a mathematical equation, you're doing mathematics and you're not going to get back to nature. Whatever you do, have a question that an experiment could resolve at the front of your thinking." So I always try to do that.

CONSTRUCTOR THEORY

A Conversation with
David Deutsch
[10.22.12]

There's a notorious problem with defining information within physics, namely that on the one hand information is purely abstract, and the original theory of computation as developed by Alan Turing and others regarded computers and the information they manipulate purely abstractly as mathematical objects. Many mathematicians to this day don't realize that information is physical and that there is no such thing as an abstract computer. Only a physical object can compute things.

~ ~ ~ ~

I think it's important to regard science not as an enterprise for the purpose of making predictions, but as an enterprise for the purpose of discovering what the world is really like, what is really there, how it behaves and why.
 

DAVID DEUTSCH is a Physicist at the University of Oxford. His research in quantum physics has been influential and highly acclaimed. He is the author of The Beginning of Infinity and The Fabric of Reality. David Deutsch's Edge Bio Page

REALITY CLUB: Arnold Trehub, Harold Levey

CONSTRUCTOR THEORY

Topic: 

  • UNIVERSE
http://vimeo.com/83527852

There's a notorious problem with defining information within physics, namely that on the one hand information is purely abstract, and the original theory of computation as developed by Alan Turing and others regarded computers and the information they manipulate purely abstractly as mathematical objects. Many mathematicians to this day don't realize that information is physical and that there is no such thing as an abstract computer. Only a physical object can compute things.

~~

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