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Hawking and Mlodinow open their book with the provocative claim, "Traditionally these are questions for philosophy, but philosophy is dead" [Hawking2010, pg. 5]. What's more, the book contains numerous jabs at belief in God, such as "the multiverse concept can explain the fine-tuning of physical law without the need for a benevolent creator who made the universe for our benefit [pg. 165], and "It is not necessary to invoke God to light the blue touch paper and set the universe going [pg. 180].
But in spite of these eye-catching quotes and the book's focus on string theory and the multiverse, the authors fail to fully acknowledge to the "lay" reader the profound difficulties that these theories face in gaining near-universal consensus acceptance in the physics and cosmology community. Not the least of these difficulties is the failure of M-theory to yield a single logically consistent universe, which was the original goal, but instead its implication of an ensemble of at least 10500 other universes with different structures and physical laws. And then there is the issue of experimental confirmation -- so far no one in the M-theory community has been able to devise even a single convincing experimental test. In other words, the "if" in the next-to-last sentence of the book ("If the theory is confirmed by observation, it will be the successful conclusion of a search...") is a very big "if" indeed. Recently several leading physicists have expressed grave concern that the field may be on the wrong track in pursuing these theories for so long without tangible empirical validation. This is discussed in greater detail at Multiverse and Anthropic.
In any event, it is unfortunate that Hawking and Mlodinow were not content to leave readers with at least an open-minded view towards God and philosophy, as Hawking did in his earlier book A Brief History of Time, which concluded, "If we find the answer to [why the universe exists], it would be the ultimate triumph of human reason -- for then we should know the mind of God." [Hawking1988]. It may be true, even if the string theory-multiverse construct of cosmology ultimately gains more-or-less complete acceptance as the "theory of everything," that this does not require the intervention of a supernatural being or god. But surely this does not rule out the existence of God in a more general sense. Unfortunately, this subtle but important point will be lost on the vast majority readers of the Hawking-Mlodinow book, and certainly will be lost on the vast majority of those who have heard the quip about God through news reports and Internet postings.
It is worth pointing out that several published reviews of the Hawking-Mlodinow book by leading scientists and scholars have either been sharply critical or at best lukewarm [Carroll2010; Davies2010a; Garner2010; Horgan2010; ICN2010; Johnston2010; Woit2010]. For example, scholar Dwight Garner, in a review published in the New York Times, comments that this book is "disappointingly tinny and inelegant" [Garner2010]. Theoretical physicist Sean Carroll concludes his review in the Wall Street Journal with the comment, "It is unfortunate that Messrs. Hawking and Mlodinow choose to open their book by picking a pointless disciplinary fight." [Carroll2010]. John Horgan, who operates a blog commentary for Scientific American, describes the book in these rather unflattering terms [Horgan2010]:
M-theory, theorists now realize, comes in an almost infinite number of versions, which "predict" an almost infinite number of possible universes. Critics call this the "Alice's restaurant problem," a reference to the refrain of the old Arlo Guthrie folk song: "You can get anything you want at Alice's restaurant." Of course, a theory that predicts everything really doesn't predict anything, and hence isn't a theory at all. Proponents, including Hawking, have tried to turn this bug into a feature, proclaiming that all the universes "predicted" by M-theory actually exist. "Our universe seems to be one of many," Hawking and Mlodinow assert. ...
The anthropic principle has always struck me as so dumb that I can't understand why anyone takes it seriously. It's cosmology's version of creationism. [The weak anthropic principle] is tautological and [the strong anthropic principle] is teleological. The physicist Tony Rothman, with whom I worked at Scientific American in the 1990s, liked to say that the anthropic principle in any form is completely ridiculous and hence should be called CRAP. ...
Now, Hawking is telling us that unconfirmable M-theory plus the anthropic tautology represents the end of that quest [to solve the riddle of existence]. If we believe him, the joke's on us.
Astronomer Paul Davies, in his review in the U.K. Guardian, agrees that there may be no compelling need, based on current physical theories, to presume that a supernatural being created the universe. "But when it comes to the laws that explain the big bang, we are in murkier waters." Davies elaborates as follows [Davies2010a]:
So is that the end of the story? Can the multiverse provide a complete and closed account of all physical existence? Not quite. The multiverse comes with a lot of baggage, such as an overarching space and time to host all those bangs, a universe-generating mechanism to trigger them, physical fields to populate the universes with material stuff, and a selection of forces to make things happen. Cosmologists embrace these features by envisaging sweeping "meta-laws" that pervade the multiverse and spawn specific bylaws on a universe-by-universe basis. The meta-laws themselves remain unexplained -- eternal, immutable transcendent entities that just happen to exist and must simply be accepted as given. In that respect the meta-laws have a similar status to an unexplained transcendent god.
Famed mathematical physicist Roger Penrose, perhaps the highest-profile scientist to comment on the Hawking-Mlodinow book so far, characterizes it as "misleading," because the M-theory that is the basis for the claims on God is "not even a theory", "hardly science," but instead merely "a collection of hopes, ideas and aspirations" that have "absolutely no support from observation" [ICN2010].
Mathematical physicist Peter Woit, author of Not Even Wrong: The Failure of String Theory and the Search for Unity in Physical Law [Woit2006], is highly critical of the Hawking-Mlodinow book's presentation of M-theory as the definitive theory of everything, and is even more critical of the book's comments on God in light of the status of this theory. He notes that the Hawking-Mlodinow book begins with the following explanation of what makes a good physical model [Woit2010, quoting from Hawking2010]:
A model is a good model if it (1) Is elegant; (2) Contains few arbitrary or adjustable elements; (3) Agrees with and explains all existing observations; and (4) Makes detailed predictions about future observations that can disprove or falsify the model if they are not borne out.
Woit notes that the book fails to acknowledge the fact that M-theory satisfies none of these criteria. Woit then comments on the treatment of religion in the Hawking-Mlodinow book [Woit2010]:
One thing that is sure to generate sales for a book of this kind is to somehow drag in religion. The book's rather conventional claim that "God is unnecessary" for explaining physics and early universe cosmology has provided a lot of publicity for the book. I'm in favor of naturalism and leaving God out of physics as much as the next person, but if you're the sort who wants to go to battle in the science/religion wars, why you would choose to take up such a dubious weapon as M-theory mystifies me. A British journalist contacted me about this recently and we talked about M-theory and its problems. She wanted me to comment on whether physicists doing this sort of thing are relying upon "faith" in much the same way as religious believers. I stuck to my standard refusal to get into such discussions, but, thinking about it, have to admit that the kind of pseudo-science going on here and being promoted in this book isn't obviously any better than the faith-based explanations of how the world works favored by conventional religions.
Hamish Johnston, a British physicist who operates the physicsworld.com website, agrees with Penrose's and Woit's assessment of the status of M-theory, and is very concerned that the comments about God in the Hawking-Mlodinow book will hamper efforts by the British physics community to defend their funding in the face of serious threatened budget cuts [Johnston2010]:
Hawking explained that M-theory allows the existence of a "multiverse" of different universes, each with different values of the physical constants. We exist in our universe not by the grace of God, according to Hawking, but simply because the physics in this particular universe is just right for stars, planets and humans to form.
There is just one tiny problem with all this -- there is currently little experimental evidence to back up M-theory. In other words, a leading scientist is making a sweeping public statement on the existence of God based on his faith in an unsubstantiated theory. ...
Physicists need the backing of the British public to ensure that the funding cuts don't hit them disproportionately. This could be very difficult if the public think that most physicists spend their time arguing about what unproven theories say about the existence of God.
n summary, the 2010 book by Hawking and Mlodinow, while qualifying as a very readable and even mildly entertaining introduction to recent developments in physics and cosmology, presents M-theory (i.e., the latest version of string theory) as a more-or-less universally validated theory of everything, when it is not. Furthermore, the book takes provocative and unjustified jabs at both philosophy and religion. It is most unfortunate that a book that takes such liberties has been authored by such prominent scientists.
For additional details, see
Big bang and
Big bang theology.