Some readers may find the furor around Stephen Hawkings new book, The Grand Design, to be intriguing or disturbing. I sallied forth on the web this afternoon to see what I could find. Up-front disclaimer: I have not read the book itself — I did read Hawking’s classic A Brief History of Time some years back, but don’t see taking the time to read another such volume, carefully, in the near future. What I have done is sample about a dozen separate reviews of the book, and tried to pick out credible and key common threads, to provide an early assessment of the book’s significance. So take this for what it is worth.
The furor: here is excerpt from Reuters article as posted by Yahoo.: God did not create the universe, says Hawking
LONDON (Reuters) – God did not create the universe and the “Big Bang” was an inevitable consequence of the laws of physics, the eminent British theoretical physicist Stephen Hawking argues in a new book.
In “The Grand Design,” co-authored with U.S. physicist Leonard Mlodinow, Hawking says a new series of theories made a creator of the universe redundant, according to the Times newspaper which published extracts on Thursday.
“Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist,” Hawking writes.
“It is not necessary to invoke God to light the blue touch paper and set the universe going.”
More than one reviewer noted that this interview seems like a publicity stunt; apparently the book itself is more circumspect, refraining from overt attack on religion. There is a difference between “It is not necessary to invoke God,” [Hawking’s actual words in the interview] and the screaming headline for this article ” God did not create the universe.”
To summarize the key content of the book, I’ll quote from just one, solid review by science writer Fred Bortz :
Quantum mechanics and general relativity, both remarkably successful in their qualitative and quantitative description of nature as well as their predictive power, do not mesh with each other at the subatomic level.
Because of that mismatch, physicists seek a Holy Grail, a so-called theory of everything that unites quantum theory and relativity. In their new book, Hawking and Mlodinow argue that such a theory, which they call The Grand Design, is now within reach.
….The book is at its scientific best when explaining Richard Feynman’s contributions to the understanding of quantum theory. The authors use the example of a light beam passing through two slits to produce an interference pattern–a wave property. Even when the beam is so dim that only single particles of light (photons) go through the slits at any one time, the net result is still interference. How can a particle interfere with itself?
“According to Newtonian physics…,” they write, “each particle follows a single well-defined route from its source to the screen…. According to the quantum model, however, the particle is said to have no definite position during the time it is between the starting point and the endpoint.” Feynman interpreted that to mean “that particles take every possible path connecting these points…, and they take them all simultaneously!… Feynman formulated a mathematical expression–the Feynman sum over histories–that reflects this idea and reproduces all the laws of quantum physics.”
The book then goes on to discuss the quest for the theory of everything, including a history of string theory, an approach that replaces particles in conventional four-dimensional space-time with tiny vibrating strings in a ten-dimensional universe. String theory yields multiple interpretations of reality, which its practitioners view as approximations to a more fundamental eleven-dimensional theory called M-theory.
“No one seems to know what the ‘M’ stands for,” the authors write, “but it may be ‘master,’ ‘miracle,’ or ‘mystery.’ It seems to be all three.” A Feynman-like interpretation of M-theory predicts the simultaneous existence of multiple universes, each with different sets of fundamental constants and particles.
Because M-theory allows for so many possible universes–10 to the 500th power, give or take a factor of a googol (ten to the 100th)–critics dismiss it as not the theory of everything but the theory of anything. But Hawking and Mlodinow take a different view: “It could be that the physicists’ traditional expectation of a single theory of nature is untenable.”
In their view, a small fraction of those possible universes (but still a very large number) are suitable for the evolution of stars, planets, and life such as we experience on our particular world in our particular galaxy. In other words, according to M-theory, a universe like ours is not a miracle but inevitable.
The M-theory has been around for over a decade, so Hawking appears to be popularizing someone else’s theory, not saying anything new to physics. (The “M” stands for “membrane,” by the way). Several reviewers cautioned that the “M-theory” is not at all a settled, proven proposition. The review by Roger Penrose (a physics legend in his own right) is pretty scathing on this. Penrose is also unimpressed by Hawking’s claim to have replaced objective reality with dependence on theory or on observation:
The viewpoint of “theory-dependent realism” being espoused in this book appears to be a kind of half-way house, objective reality being not fully abandoned, but taking different forms depending upon the particular theoretical perspective it is viewed from, enabling the possibility of equivalence between black and white holes.
An illustrative example the authors provide involves goldfish trying to formulate a theory of the physical space outside their spherical goldfish bowl. The external room appears to them to have curved walls, despite being regarded as rectilinear by its human inhabitants. Yet the goldfish’s and human’s viewpoints are equally consistent, providing identical predictions for those physical actions accessible to both life forms at once. Neither viewpoint is more real than the other, being equivalent for making predictions.
I do not see what is new or “theory-dependent” about this perspective on reality. Einstein’s general theory of relativity already deals with such situations in a completely satisfactory way, in which different observers may choose to use different co-ordinate systems for local descriptions of the geometry of the single fixed over-reaching objective space-time. There is a degree of subtlety and sophistication in the mathematics, going significantly beyond what is present in Euclid’s ancient geometry of space. But the mathematical “space-time”, whereby the theory describes the world, has complete objectivity.
It is nevertheless true that current quantum theory presents threats to this objectivity of classical physics (including general relativity) and has not yet provided an accepted universally objective picture of reality. In my opinion, this reflects an incompleteness in current quantum theory, as was also Einstein’s view. It is likely that any “completion” of quantum theory to an objective picture of reality would require new mathematical ideas of subtlety and sophistication beyond even that of Einstein’s general-relativistic space-time, but this challenge is addressed to future theorists’ ingenuity and does not, in my view, represent any real threat to the existence of an objective universe. The same might apply to M-theory, but unlike quantum mechanics, M-theory enjoys no observational support whatever.
Ouch. The grand synthesis Hawking presents does not seem to contradict observations, but does not seem directly supported, either. A Wikipedia article on M-Theory also notes its tentative nature:
M-theory (and string theory) have been criticized for lacking predictive power or being untestable. Further work continues to find mathematical constructs that join various surrounding theories. New formulations are proposed to join many theoretic situations (usually by exploiting string theoretic dualities). Witten has suggested that a general formulation of M-theory will probably require the development of new mathematical language. However, the tangible success of M-theory can be questioned, given its current incompleteness and limited predictive power, even after so many years of intense research.
My understanding is that “other” universes can never even in principle interact with ours. Even if M-theory turns out to be true physics, what are the metaphysical implications? The notion of multiple universes popping out of “nothing” has been around for years, and many thinkers have pointed out that this “nothing” is not really nothing. Call it a “reality” instead of a “universe” — a reality where laws of gravity and quantum mechanics operate is not “nothing.” The question of why there is something rather than nothing does not really change. If the Intelligent Design of reality gets pushed back from one universe (which is tuned to support life) to a multiverse (where at least one universe is tuned to support life), that is no less awe-inspiring.
That said, having infinite universes raises some awkward issues about what we think we know – – I’ll close with an excerpt from the STAN 4 letter on this blog, which refers to Michael Behe’s The Edge of Evolution :
Although Behe’s objections to evolution do not stand, his treatment of the anthropic tuning of the universe is insightful. It seems clear that organic life-forms could not exist if the laws and physical constants in the universe were not tuned exactly the way they are. Some skeptics dismiss this as mere coincidence (“if the universe did not permit life, we wouldn’t be here to observe it”); more thoughtful skeptics argue that there may be an infinite number of universes in existence, with infinite variations in physical properties, so it should be no surprise that at least one universe (ours) has the properties needed to sustain life. Behe points out how the infinite multiverse alternative logically leads to such a bizarre set of possibilities of illusory observations that you would have no reason to trust your own thinking. A truly infinite multiverse, comprehending all possibilities, may well contain “freak” observers whose brains just popped into existence containing thoughts which do not correspond to any reality; and you cannot know if you are not one of those observers:
What you are at this very moment “thinking” – as well as any detailed memories you have of the past, no matter how seemingly realistic, including memories of what you think you know about “nature” – could be due to a random collocation of matter that just popped into existence. The very concepts of “gravity,” “protons,” “stars” – all you think you know about nature – could be just the pitiful delusion of a freak observer. Reality may be utterly different. Such is the intellectually toxic bequest of the infinite multiverse hypothesis.
A point of view which removes any confidence that we are observing a real universe seems less conducive to scientific inquiry than the more traditional view that there is a real world which we can observe and ponder in some valid fashion.
One more thing: Just read a cold-eyed review of Grand Design in NY Times which takes atheist [per ex-wife’s memoir] Hawking to task for cynical “Godmongering” (bringing in gratuitous religious references merely to stoke book sales), and has this to say about its style:
The real news about “The Grand Design” is how disappointingly tinny and inelegant it is. The spare and earnest voice that Mr. Hawking employed with such appeal in “A Brief History of Time” has been replaced here by one that is alternately condescending, as if he were Mr. Rogers explaining rain clouds to toddlers, and impenetrable.