Part Three



In a manner of speaking, the physicists came to the wrong book. It is interesting to note that for the most part they have little to say about the other scientists in this book, and, similarly, the other people do not comment on their work. This may have to do with the fact that the language of physics is mathematics; it may also be that ideas about complexity and evolution have not had the same relevance for cosmology and physics as they have for biology and computer science. Astronomers have studied the spectra of light emitted by distant stars billions of years ago, and have so far found no indication that the laws of physics have changed over this epoch.

Particle Cosmology, which came into its own as a science only about thirty years ago, is concerned in part with pinning down the parameters of the universe: its expansion rate, the amount of its mass, the nature of its "dark matter." Cosmologists today are also speculating on more far-reaching questions, such as how the universe was created and how its structure was determined. While some cosmologists are speculating that the laws of physics might explain the origin of the universe, the origin of the laws themselves is a problem so unfathomable that it is rarely discussed. Might the principles of adaptive complexity be at work? Is there a way in which the universe may have organized itself? Does the "anthropic principle" — the notion that the existence of intelligent observers like us is in some sense a factor in the universe's existence — have any useful part to play in cosmology?

Particle physics, on the other hand, is a field that has been suffering from its own success. Important discoveries in the 1960s and 1970s have led to the development of the so-called standard model, a theory that appears to be consistent with every reliable particle-physics experiment that has so far been performed. The theory has too many unexplained parameters, however, to be accepted as the ultimate theory of nature, and furthermore it does not provide a quantum description of gravity. The attempts to go beyond the standard model have led particle physicists to search for a unified theory of all the elementary particles and all the forces of nature. The goal of such a theory is to unify the four fundamental forces of nature — electromagnetism, the strong and the weak nuclear force, and gravity — into an all-encompassing theory, a reductionist enterprise beyond which, it is thought, we need not go. (The unification of the first three into one or another "grand unified theory" is in sight; gravity is more of a problem but a serious candidate theory for complete unification — superstring theory — has already found.) This is physics in its traditional style. It is interesting to note that the paramount particle theorist of our time, the Nobelist Murray Gell-Mann, is in the forefront of the investigation of adaptive complex systems.

The astrophysicist Martin Rees, who is not known as much for any one specific accomplishment as for his polymathic understanding of the key cosmological questions, has remained at the forefront of cosmological debates. He is currently thinking about the possibilities of multiple universes, and how to take the weak form of the anthropic principle (as opposed to the strong form, which has marked religious overtones) and use it to illuminate that particular cosmological issue. He has had several important ideas on how stars and galaxies form, how to find black holes, and on the nature of the early universe. He is now trying to understand the mysterious "dark matter" which seems to fill intergalactic space — it is the gravitational pull of this dark matter which will determine whether our universe expands forever or eventually collapses to a "big crunch." He has always been interested in the broader philosophical aspects of cosmology. For instance: Why does our universe have the special features that allowed life to evolve? Are there other universes, perhaps governed by quite different physical laws?

Alan Guth, who began his scientific life as a particle physicist, has made what some consider to be the most important contribution to cosmology in a generation: the theory of inflation. In Guth's model, the very early universe underwent a period of rapid expansion; this accounts for, among other puzzles in big-bang theory, the present-day universe's puzzling homogeneity. Guth describes himself as taking a hard-nosed view of science, although his work is very often speculative. He is currently thinking about time travel: can wormholes in the fabric of space allow us to travel backward in time? Guth thinks the answer is no, but is fascinated by the fact that no one has been able to show that time travel is forbidden by the laws of physics.

The theoretical physicist Lee Smolin is interested in the problem of quantum gravity — of reconciling quantum theory with Einstein's gravitational theory, the theory of general relativity, to produce a correct picture of spacetime. He also thinks about creating what he calls a theory of the whole universe, which would explain its evolution, and he has invented a method by which natural selection might operate on the cosmic scale.

The theoretical physicist Paul Davies works in the fields of cosmology, gravitation, and quantum field theory, with particular emphasis on black holes and the origin of the universe. A prolific and influential popularizer of physics, he has written more than a dozen books. Here he presents the antireductionist agenda, and makes the case for moving both physics and biology onto "the synthetic path," recognizing the importance of the organizational and qualitative features of complex systems. He advocates a meeting of the minds between physicists and biologists, noting that complicated systems, whether biological or cosmological, are more than just the accretion of their parts but operate with their own internal laws and logic.

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Excerpted from The Third Culture: Beyond the Scientific Revolution by John Brockman (Simon & Schuster, 1995) . Copyright 1995 by John Brockman. All rights reserved.