All these multiverse ideas lead to a remarkable synthesis between cosmology and physics...But they also lead to the extraordinary consequence that we may not be the deepest reality, we may be a simulation. The possibility that we are creations of some supreme, or super-being, blurs the boundary between physics and idealist philosophy, between the natural and the supernatural, and between the relation of mind and multiverse and the possibility that we're in the matrix rather than the physics itself.

Introductory Remarks

Cosmology and astrophysics are branches of physics in which one needs an unusual combination of breadth and depth to excel. Martin Rees is arguably the finest all-round theoretical physicist working today. I do not always agree with him—especially in areas outside physics itself—but I always want to know his opinion. As does every wise person.
—David Deutsch

I have known and admired Martin Rees since the early 1970's when we were postdocs together at Cambridge University. Even at that stage Martin's extraordinary breadth of knowledge and expertise were apparent. Pick almost any topic in astronomy or physics, and he would have a carefully evaluated position worked out. He is one of only a few great scientists who is both open-minded and healthily-skeptical. At a time in his career when he could justifiably rest on his laurels, Martin Rees is as energetic and active as ever, offering stunning insights into many emerging scientific fields.
— Paul Davies

Martin Rees one of the most influential people working in astrophysical and cosmological theory. He is simultaneously open to new ideas and suggestions and careful and rigorous in his response and criticisms. Also, it's difficult to suggest an idea about the evolution of structure in the universe or the formation of the galaxies that he hasn't thought of or played with or perhaps even written about at some time. Much of the credit for what I like to think of as the discovery that the laws of nature are special in ways that allow the universe to be very structured is due to him.
—Lee Smolin

Martin Rees is my favorite theoretical astrophysicist. He is not only incredibly knowledgeable, but he is also wonderfully helpful to his colleagues. He has contributed over 500 papers to the scientific literature, making important contributions to almost every aspect of astrophysics. He is especially well-known for his work on galaxy formation and the theory of cold dark matter, and also for his work on active galactic nuclei and the black holes that are believed to drive them.
—Alan Guth

There are two types of cosmologists active today: those who seek the physical principles driving the global properties of the Universe, and those who concentrate on the details of astrophysical objects, like galaxies, quasars, and black holes, that give complementary information about structure at smaller distances. Martin Rees is one of the few cosmologists exploring both venues, giving him a unique perspective from which to develop scientific ideas, and to synthesize known ideas for a broader audience. He always has something
interesting to say.
—Lisa Randall

SIR MARTIN REES is Royal Society Professor at Cambridge University, Fellow of King's College, the UK's Astronomer Royal, and a Fellow of the Royal Society. He was previously Plumian Professor of Astronomy and Experimental Philosophy at Cambridge, having been elected to this chair at the age of thirty, succeeding Fred Hoyle. He has originated many key cosmological ideas: for example, he was the first to suggest that the fantastically energetic cores of quasars may be powered by giant black holes. For the last twenty years, he has directed a wide-ranging research program at Cambridge's Institute of Astronomy.

He is the author of several books, including Gravity's Fatal Attraction (with Mitchell Begelman); New Perspectives in Astrophysical Astronomy; Before the Beginning: Our Universe and Others; Just Six Numbers: The Deep Forces that Shape the Universe; Our Cosmic Habitat; and Our Final Hour: A Scientist's Warning: How Terror, Error, and Environmental Disaster Threaten Humankind's Future in this Century—on Earth and Beyond (published in the UK as Our Final Century: The 50/50 Threat to Humanity's Survival).

Martin Rees' Edge Bio page 

David Deutsch's Edge Bio Page
Paul Davies' Edge Bio Page
Lee Smolin's Edge Bio Page
Alan Guth's Edge Bio Page
Lisa Randall 's Edge Bio Page 

Science is a kind of open laboratory for a democracy. It's a way to experiment with the ideals of our democratic societies. For example, in science you must accept the fact that you live in a community that makes the ultimate judgment as to the worth of your work. But at the same time, everybody's judgment is his or her own. The ethics of the community require that you argue for what you believe and that you try as hard as you can to get results to test your hunches, but you have to be honest in reporting the results, whatever they are. You have the freedom and independence to do whatever you want, as long as in the end you accept the judgment of the community. Good science comes from the collision of contradictory ideas, from conflict, from people trying to do better than their teachers did, and I think here we have a model for what a democratic society is about. There's a great strength in our democratic way of life, and science is at the root of it.

It's only since the middle 1980s that real progress began to be made on unifying relativity and quantum theory. The turning point was the invention of not one but two approaches: loop quantum gravity and string theory. Since then, we have been making steady progress on both of these approaches. In each case, we are able to do calculations that predict surprising new phenomena. Still, we are not done. Neither is yet in final form; there are still things to understand. But the really important news is that there is now a real chance of doing experiments that will test the new predictions of these theories.

This is important, because we're in the uncomfortable situation of having two well-developed candidates for the quantum theory of gravity. We need to reduce these to one theory. We can do this either by finding that one is wrong and the other right, or by finding that the two theories can themselves be unified.

LEE SMOLIN, a theoretical physicist, is concerned with quantum gravity, "the name we give to the theory that unifies all the physics now under construction." More specifically, he is a co-inventor of an approach called loop quantum gravity. In 2001, he became a founding member and research physicist of the Perimeter Institute for Theoretical Physics, in Waterloo, Ontario. Smolin is the author of The Life of The Cosmos and Three Roads to Quantum Gravity.

Lee Smolin's Edge Bio Page

Additional spatial dimensions may seem like a wild and crazy idea at first, but there are powerful reasons to believe that there really are extra dimensions of space. One reason resides in string theory, in which it is postulated that the particles are not themselves fundamental but are oscillation modes of a fundamental string. 

LISA RANDALL is a professor of physics at Harvard University, where she also earned her PhD (1987). She was a President's Fellow at the University of California at Berkeley, a postdoctoral fellow at Lawrence Berkeley Laboratory, and a junior fellow at Harvard before joining the MIT faculty in 1991. Between 1998 and 2000, she had a joint appointment at Princeton and MIT as a full professor, and she moved to Harvard as a full professor in 2001. Her research in theoretical high energy physics is primarily related to exploring the physics underlying the standard model of particle physics. This has involved studies of supersymmetry and, most recently, extra dimensions of space.

Lisa Randall's Edge Bio Page

...in the last year I've been involved in the development of an alternative theory that turns the cosmic history topsy-turvy. All the events that created the important features of our universe occur in a different order, by different physics, at different times, over different time scales—and yet this model seems capable of reproducing all of the successful predictions of the consensus picture with the same exquisite detail.

PAUL STEINHARDT is the Albert Einstein Professor in Science and on the faculty of both the Departments of Physics and Astrophysical Sciences at Princeton University.

He is one of the leading theorists responsible for inflationary theory. He constructed the first workable model of inflation and the theory of how inflation could produce seeds for galaxy formation. He was also among the first to show evidence for dark energy and cosmic acceleration, introducing the term "quintessence" to refer to dynamical forms of dark energy. With Neil Turok he has pioneered mathematical and computational techniques which decisively disproved rival theories of structure formation such as cosmic strings. He made leading contributions to inflationary theory and to our understanding of the origin of the matter-antimatter asymmetry in the Universe. Hence, the authors not only witnessed but also led firsthand the revolutionary developments in the standard cosmological model caused by the fusion of particle physics and cosmology in the last 20 years.

Paul Steinhardt's Edge Bio Page

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