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Cosmic Clowning: Stephen Hawking's "new" theory of everything is the same old CRAP
Editor's note (9/14/10): This post has been slightly modified.
I've always thought of Stephen Hawking—whose new book The Grand Design (Bantam 2010), co-written with Leonard Mlodinow, has become an instant bestseller—less as a scientist than as a cosmic, comic performance artist, who loves goofing on his fellow physicists and the rest of us.
This penchant was already apparent in 1980, when the University of Cambridge named Hawking Lucasian Professor of Mathematics at Cambridge, the chair held three centuries earlier by Isaac Newton. Many would have been cowed into caution by such an honor. But in his inaugural lecture, "Is the End in Sight for Theoretical Physics?", Hawking predicted that physics was on the verge of a unified theory so potent and complete that it would bring the field to a close. The theory would not only unite relativity and quantum mechanics into one tidy package and "describe all possible observations." It would also tell us why the big bang banged and spawned our weird world rather than something entirely different.
At the end of his speech Hawking slyly suggested that, given the "rapid rate of development" of computers, they might soon become so smart that they "take over altogether" in physics. "So maybe the end is in sight for theoretical physicists," he said, "if not for theoretical physics." This line was clearly intended as a poke in his colleagues' ribs. Wouldn't it be ironic if our mindless machines usurped our place as discoverers of Cosmic Truth? Hilarious!
The famous last line of Hawking's monumental bestseller A Brief History of Time (Bantam 1988) was also a joke, although many people didn't get it at the time. A final theory of physics, Hawking declared, "would be the ultimate triumph of human reason—for then we should know the mind of God." Hawking seemed to imply that physics was going to come full circle back to its spiritual roots, yielding a mystical revelation that tells us not just what the universe is but why it is. Science and religion are compatible after all! Yay!
But Hawking ain't one of these New Agey, feel-good physicist–deists like John Barrow, Paul Davies, Freeman Dyson or other winners of the Templeton Prize for Progress Toward Research or Discoveries about Spiritual Realities. Deep inside Brief History Hawking showed his true colors when he discussed the no-boundary proposal, which holds that the entire history of the universe, all of space and time, forms a kind of four-dimensional sphere. The proposal implies that speculation about the beginning or end of the universe is as meaningless as talking about the beginning or end of a sphere.
In the same way a unified theory of physics might be so seamless, perfect and complete that it even explains itself. "What place, then, for a creator?" Hawking asked. There is no place, he replied. Or rather, a final theory would eliminate the need for a God, a creator, a designer. Hawking's first wife, a devout Christian, knew what he was up to. After she and Hawking divorced in the early 1990s she revealed that one of the reasons was his scorn for religion.
Hawking's atheism is front and center in Grand Design. In an excerpt Hawking and Mlodinow declare, "There is a sound scientific explanation for the making of our world—no Gods required." But Hawking is, must be, kidding once again. The "sound scientific explanation" is M-theory, which Hawking calls (in a blurb for Amazon) "the only viable candidate for a complete 'theory of everything'."
Actually M-theory is just the latest iteration of string theory, with membranes (hence the M) substituted for strings. For more than two decades string theory has been the most popular candidate for the unified theory that Hawking envisioned 30 years ago. Yet this popularity stems not from the theory's actual merits but rather from the lack of decent alternatives and the stubborn refusal of enthusiasts to abandon their faith.
M-theory suffers from the same flaws that string theories did. First is the problem of empirical accessibility. Membranes, like strings, are supposedly very, very tiny—as small compared with a proton as a proton is compared with the solar system. This is the so-called Planck scale, 10^–33 centimeters. Gaining the kind of experimental confirmation of membranes or strings that we have for, say, quarks would require a particle accelerator 1,000 light-years around, scaling up from our current technology. Our entire solar system is only one light-day around, and the Large Hadron Collider, the world's most powerful accelerator, is 27 kilometers in circumference.
Hawking recognized long ago that a final theory—because it would probably involve particles at the Planck scale—might never be experimentally confirmable. "It is not likely that we shall have accelerators powerful enough" to test a unified theory "within the foreseeable future—or indeed, ever," he said in his 1980 speech at Cambridge. He nonetheless hoped that in lieu of empirical evidence physicists would discover a theory so logically inevitable that it excluded all alternatives.
Quite the opposite has happened. 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.
Why do we find ourselves in this particular universe rather than in one with, say, no gravity or only two dimensions, or a Bizarro world in which Glenn Beck is a left-wing rather than right-wing nut? To answer this question, Hawking invokes the anthropic principle, a phrase coined by physicist Brandon Carter in the 1970s. The anthropic principle comes in two versions. The weak anthropic principle, or WAP, holds merely that any cosmic observer will observe conditions, at least locally, that make the observer's existence possible. The strong version, SAP, says that the universe must be constructed so as to make observers possible.
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. WAP is tautological and SAP 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.
In his 1980 speech in Cambridge Hawking mentioned the anthropic principle—which he paraphrased as "Things are as they are because we are"—as a possible explanation for the fact that our cosmos seems to be fine-tuned for our existence. But he added that "one cannot help feeling that there is some deeper explanation."
Like millions of other people I admire Hawking's brilliance, wit, courage and imagination. His prophecy of the end of physics inspired me to write The End of Science (which he called "garbage"). Hawking also played a central role in one of the highlights of my career. It dates back to the summer of 1990, when I attended a symposium in a remote Swedish resort on "The Birth and Early Evolution of Our Universe." The meeting was attended by 30 of the world's most prominent cosmologists, including Hawking.
Toward the end of the meeting, everyone piled into a bus and drove to a nearby village to hear a concert in a Lutheran church. When the scientists entered the church, it was already packed. The orchestra, a motley assortment of blond-haired youths and wizened, bald elders clutching violins, clarinets and other instruments, was seated at the front of the church. Their neighbors jammed the balconies and seats at the rear of the building.
The scientists filed down the center aisle to pews reserved for them at the front of the church. Hawking led the way in his motorized wheelchair. The townspeople started to clap, tentatively at first, then passionately. These religious folk seemed to be encouraging the scientists, and especially Hawking, in their quest to solve the riddle of existence.
Now, Hawking is telling us that unconfirmable M-theory plus the anthropic tautology represents the end of that quest. If we believe him, the joke's on us.
Clarification (9/14/10): My original post referred to Stephen Hawking's "smirk." Apparently many readers assume that Hawking can't control his expression and that I was mocking him for this symptom of his paralysis. When I met Hawking, he could and did grin on purpose, and I assumed that's still the case. I apologize for any offense caused by my (now deleted) remark.
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The Economist Understanding the universe
Order of creation
Even Stephen Hawking doesn't quite manage to explain why we are here
Sep 9th 2010
The Grand Design. By Stephen Hawking and Leonard Mlodinow. Bantam; 198 pages; $28 and £18.99. Buy from Amazon.com, Amazon.co.uk
IN 1988, Stephen Hawking, a British cosmologist, ended his best-selling book, “A Brief History of Time”, on a cliff hanger. If we find a physical theory that explains everything, he wrote—suggesting that this happy day was not too far off—“then we would know the mind of God.” But the professor didn’t mean it literally. God played no part in the book, which was renowned for being bought by everyone and understood by few. Twenty-two years later, Professor Hawking tells a similar story, joined this time by Leonard Mlodinow, a physicist and writer at the California Institute of Technology.
In their “The Grand Design”, the authors discuss “M-theory”, a composite of various versions of cosmological “string” theory that was developed in the mid-1990s, and announce that, if it is confirmed by observation, “we will have found the grand design.” Yet this is another tease. Despite much talk of the universe appearing to be “fine-tuned” for human existence, the authors do not in fact think that it was in any sense designed. And once more we are told that we are on the brink of understanding everything.
The authors may be in this enviable state of enlightenment, but most readers will not have a clue what they are on about. Some physics fans will enjoy “The Grand Design” nonetheless. The problem is not that the book is technically rigorous—like “A Brief History of Time”, it has no formulae—but because whenever the going threatens to get tough, the authors retreat into hand-waving, and move briskly on to the next awe-inspiring notion. Anyone who can follow their closing paragraphs on the relation between negative gravitational energy and the creation of the universe probably knows it all already. This is physics by sound-bite.
There are some useful colour diagrams and photographs, and the prose is jaunty. The book is peppered with quips, presumably to remind the reader that he is not studying for an exam but is supposed to be having fun. These attempted jokes usually fuse the weighty with the quotidian, in the manner of Woody Allen, only without the laughs. (“While perhaps offering great tanning opportunities, any solar system with multiple suns would probably never allow life to develop.”) There is a potted history of physics, which is adequate as far as it goes, though given what the authors have to say about Aristotle, one can only hope that they are more reliable about what happened billions of years ago at the birth of the universe than they are about what happened in Greece in the fourth century BC. Their account appears to be based on unreliable popularisations, and they cannot even get right the number of elements in Aristotle’s universe (it is five, not four).
The authors rather fancy themselves as philosophers, though they would presumably balk at the description, since they confidently assert on their first page that “philosophy is dead.” It is, allegedly, now the exclusive right of scientists to answer the three fundamental why-questions with which the authors purport to deal in their book. Why is there something rather than nothing? Why do we exist? And why this particular set of laws and not some other?
It is hard to evaluate their case against recent philosophy, because the only subsequent mention of it, after the announcement of its death, is, rather oddly, an approving reference to a philosopher’s analysis of the concept of a law of nature, which, they say, “is a more subtle question than one may at first think.” There are actually rather a lot of questions that are more subtle than the authors think. It soon becomes evident that Professor Hawking and Mr Mlodinow regard a philosophical problem as something you knock off over a quick cup of tea after you have run out of Sudoku puzzles.
The main novelty in “The Grand Design” is the authors’ application of a way of interpreting quantum mechanics, derived from the ideas of the late Richard Feynman, to the universe as a whole. According to this way of thinking, “the universe does not have just a single existence or history, but rather every possible version of the universe exists simultaneously.” The authors also assert that the world’s past did not unfold of its own accord, but that “we create history by our observation, rather than history creating us.” They say that these surprising ideas have passed every experimental test to which they have been put, but that is misleading in a way that is unfortunately typical of the authors. It is the bare bones of quantum mechanics that have proved to be consistent with what is presently known of the subatomic world. The authors’ interpretations and extrapolations of it have not been subjected to any decisive tests, and it is not clear that they ever could be.
Once upon a time it was the province of philosophy to propose ambitious and outlandish theories in advance of any concrete evidence for them. Perhaps science, as Professor Hawking and Mr Mlodinow practice it in their airier moments, has indeed changed places with philosophy, though probably not quite in the way that they think.
Books and Arts
Stephen Hawking's big bang gaps
The laws that explain the universe's birth are less comprehensive than Stephen Hawking suggests
The Guardian, Saturday 4 September 2010
Cosmologists are agreed that the universe began with a big bang 13.7 billion years ago. People naturally want to know what caused it. A simple answer is nothing: not because there was a mysterious state of nothing before the big bang, but because time itself began then – that is, there was no time "before" the big bang. The idea is by no means new. In the fifth century, St Augustine of Hippo wrote that "the universe was created with time and not in time".
Religious people often feel tricked by this logic. They envisage a miracle-working God dwelling within the stream of time for all eternity and then, for some inscrutable reason, making a universe (perhaps in a spectacular explosion) at a specific moment in history.
That was not Augustine's God, who transcended both space and time. Nor is it the God favoured by many contemporary theologians. In fact, they long ago coined a term for it – "god-of-the-gaps" – to deride the idea that when science leaves something out of account, then God should be invoked to plug the gap. The origin of life and the origin of consciousness are favourite loci for a god-of-the-gaps, but the origin of the universe is the perennial big gap.
In his new book, Stephen Hawking reiterates that there is no big gap in the scientific account of the big bang. The laws of physics can explain, he says, how a universe of space, time and matter could emerge spontaneously, without the need for God. And most cosmologists agree: we don't need a god-of-the-gaps to make the big bang go bang. It can happen as part of a natural process. A much tougher problem now looms, however. What is the source of those ingenious laws that enable a universe to pop into being from nothing?
Traditionally, scientists have supposed that the laws of physics were simply imprinted on the universe at its birth, like a maker's mark. As to their origin, well, that was left unexplained.
In recent years, cosmologists have shifted position somewhat. If the origin of the universe was a law rather than a supernatural event, then the same laws could presumably operate to bring other universes into being. The favoured view now, and the one that Hawking shares, is that there were in fact many bangs, scattered through space and time, and many universes emerging therefrom, all perfectly naturally. The entire assemblage goes by the name of the multiverse.
Our universe is just one infinitesimal component amid this vast – probably infinite – multiverse, that itself had no origin in time. So according to this new cosmological theory, there was something before the big bang after all – a region of the multiverse pregnant with universe-sprouting potential.
A refinement of the multiverse scenario is that each new universe comes complete with its very own laws – or bylaws, to use the apt description of the cosmologist Martin Rees. Go to another universe, and you would find different bylaws applying. An appealing feature of variegated bylaws is that they explain why our particular universe is uncannily bio-friendly; change our bylaws just a little bit and life would probably be impossible. The fact that we observe a universe "fine-tuned" for life is then no surprise: the more numerous bio-hostile universes are sterile and so go unseen.
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.
According to folklore the French physicist Pierre Laplace, when asked by Napoleon where God fitted into his mathematical account of the universe, replied: "I had no need of that hypothesis." Although cosmology has advanced enormously since the time of Laplace, the situation remains the same: there is no compelling need for a supernatural being or prime mover to start the universe off. But when it comes to the laws that explain the big bang, we are in murkier waters.
Stephen Hawking's big bang gaps | Paul Davies
This article appeared on p30 of the Main section section of the Guardian on Saturday 4 September 2010. It was published on guardian.co.uk at 08.30 BST on Saturday 4 September 2010.
Editorial: Hawking's faith in M-theory
Craig Callender, contributor
Three decades ago, Stephen Hawking famously declared that a "theory of everything" was on the horizon, with a 50 per cent chance of its completion by 2000. Now it is 2010, and Hawking has given up. But it is not his fault, he says: there may not be a final theory to discover after all. No matter; he can explain the riddles of existence without it.
The Grand Design, written with Leonard Mlodinow, is Hawking's first popular science book for adults in almost a decade. It duly covers the growth of modern physics (quantum mechanics, general relativity, modern cosmology) sprinkled with the wild speculation about multiple universes that seems mandatory in popular works these days. Short but engaging and packed with colourful illustrations, the book is a natural choice for someone wanting a quick introduction to mind-bending theoretical physics.
Early on, the authors claim that they will be answering the ultimate riddles of existence - and that their answer won't be "42". Their starting point for this bold claim is superstring theory.
In the early 1990s, string theory was struggling with a multiplicity of distinct theories. Instead of a single theory of everything, there seemed to be five. Beginning in 1994, though, physicists noticed that, at low energies, some of these theories were "dual" to others - that is, a mathematical transformation makes one theory look like another, suggesting that they may just be two descriptions of the same thing. Then a bigger surprise came: one string theory was shown to be dual to 11-dimensional supergravity, a theory describing not only strings but membranes, too. Many physicists believe that this supergravity theory is one piece of a hypothetical ultimate theory, dubbed M-theory, of which all the different string theories offer us mere glimpses.
This multiplicity of distinct theories prompts the authors to declare that the only way to understand reality is to employ a philosophy called "model-dependent realism". Having declared that "philosophy is dead", the authors unwittingly develop a theory familiar to philosophers since the 1980s, namely "perspectivalism". This radical theory holds that there doesn't exist, even in principle, a single comprehensive theory of the universe. Instead, science offers many incomplete windows onto a common reality, one no more "true" than another. In the authors' hands this position bleeds into an alarming anti-realism: not only does science fail to provide a single description of reality, they say, there is no theory-independent reality at all. If either stance is correct, one shouldn't expect to find a final unifying theory like M-theory - only a bunch of separate and sometimes overlapping windows.
So I was surprised when the authors began to advocate M-theory. But it turns out they were unconventionally referring to the patchwork of string theories as "M-theory" too, in addition to the hypothetical ultimate theory about which they remain agnostic.
M-theory in either sense is far from complete. But that doesn't stop the authors from asserting that it explains the mysteries of existence: why there is something rather than nothing, why this set of laws and not another, and why we exist at all. According to Hawking, enough is known about M-theory to see that God is not needed to answer these questions. Instead, string theory points to the existence of a multiverse, and this multiverse coupled with anthropic reasoning will suffice. Personally, I am doubtful.
Take life. We are lucky to be alive. Imagine all the ways physics might have precluded life: gravity could have been stronger, electrons could have been as big as basketballs and so on. Does this intuitive "luck" warrant the postulation of God? No. Does it warrant the postulation of an infinity of universes? The authors and many others think so. In the absence of theory, though, this is nothing more than a hunch doomed - until we start watching universes come into being - to remain untested. The lesson isn't that we face a dilemma between God and the multiverse, but that we shouldn't go off the rails at the first sign of coincidences.
Craig Callender is a philosopher of physics at the University of California, San Diego