That may seem to answer the question ‘Why do we exist?’ Is it a complete answer? In the Game of Life, it doesn’t matter what pattern you start with – any ‘initial conditions’ will give you those same sorts of results – but not just any set of laws, because it is the laws that determine the evolution of the system. Which refers back to the first question: ‘Why this particular set of laws and not some other?’
Summing up so far, then, with regard to Hawking’s three questions, he and Mlodinow have answered the first (‘Why this particular set of laws and not some other?’) for our own universe with the idea that we have a particular set of laws because of the way the extra dimensions are curled up. Can they answer it for the overarching laws that govern the entire string theory landscape, the entire multiverse, the laws we do not yet know? They have said that of all the supersymmetric theories of gravity, M-theory is the most general, making it the only candidate for a complete theory of the universe. ‘Candidate’ it still is, awaiting proof, but Hawking believes it promises to be a model of a multiverse that includes us, because there is no other consistent model.16
They have answered the third question (‘Why do we exist?’) by saying that, in the multitude of possible universes, a universe that allows for our existence is highly probable and, from there, even if there were only a very simple set of laws in place (dictated by the way the extra dimensions curl), it is not difficult to arrive at us (think of the game).
The second of the questions (‘Why is there something rather than nothing?’) is more fundamental and much more difficult. An answer would have to account for much more than our universe, its laws and us. It would have to account for the very existence of the unknown theory that underlies the M-theory family of theories. Hawking thinks the multiverse ruled by this family of theories ‘creates itself’, but he does not explain how. Even the often-heard statement that ‘nothingness is unstable and tends to decay into something’ implies that a certain set of probabilities must already be in place. This question – ‘Why is there something rather than nothing?’ – Hawking and Mlodinow have left unanswered.
Though many of Hawking’s colleagues have high hopes indeed for M-theory, few join him in his enormous optimism about its total explanatory power. There were questions that hung in the air at the close of A Brief History of Time, eloquently stated, evoking grand hopes that we might some day solve these mysteries. The attempt actually to answer all of them in The Grand Design falls short.
Critics of the book were not enthusiastic, and their lack of enthusiasm seemed based not on disagreement with the authors but on disappointment that this was not a more powerful book. The Economist commented that ‘whenever the going threatens to get tough, the authors retreat into hand-waving and move briskly on’17 … ‘There are actually rather a lot of questions that are more subtle than the authors think.’18 As for the claim that the ideas presented in the book have passed every experimental test to which they have been put, that is ‘misleading’ … ‘It is the bare bones of quantum mechanics that have proved to be consistent with what is presently known of the sub-atomic 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.’19 Dwight Garner, in The New York Times, wrote that ‘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.’ Garner also accused Hawking of ‘Godmongering’, as the writer Timothy Ferris has called it, when an author who is not religious makes statements about God and religious belief solely to sell books.20
There is nothing disappointing or feeble, however, about the ‘top-down’ approach and Hawking’s and Mlodinow’s presentation of M-theory. Hawking’s statement about their implications for the study of science is one of the best passages in the book. Hawking believes we are:
at a critical point in the history of science, in which we must alter our conception of goals and of what makes a physical theory acceptable. It appears that the fundamental numbers, and even the form, of the apparent laws of nature are not demanded by logic or physical principle. The parameters are free to take on any values and the laws to take on any form that leads to a self-consistent mathematical theory, and they do take on different values and different forms in different universes. That may not satisfy our human desire to be special or to discover a neat package to contain all the laws of physics, but it does seem to be the way of nature.21
What does it mean for banishing belief in God? The disparagement of belief in The Grand Design is much more frequent and assertive than in Hawking’s other books. But the more grand the design becomes – and Hawking’s is a spectacularly grand design – the more those readers who find Hawking’s science convincing and also believe in God are bound to find cause for wonder in the elegant complexity of the multiverse vision.
The religious discussion, sometimes heated, erupted as soon as the book reached reviewers and the public. Perusing all that, one is surprised to find how many of the discussants, coming from both viewpoints, clearly have not read Hawking’s and Mlodinow’s book. Among those who have, it is perhaps not so surprising to find atheists who nevertheless do not feel that Hawking and Mlodinow succeed in banishing the need for a creator, and theists who think he has done a pretty thorough job of it. It seems that one’s atheism or theism can remain essentially untouched by Hawking’s arguments, perhaps because such choices are very often based on reasons that have nothing to do with science. Among those who disagree with Hawking, the most interesting arguments take two forms.
(1) In spite of the hugely comprehensive explanatory power of Hawking’s model – and even if this should some day turn out to be model-independent reality – a question that is as old as human thought is still left hanging: why is there something – a grand design – rather than nothing? The ‘something’ in the M-theory model is far, far grander and more extensive than has ever been proposed before. But why is there anything to have a model of? Granted, a religious answer to that question, ‘God’, does no better than a scientific one which argues that ‘There is a fundamental mathematical logic that does not allow “nothing”’. ‘God’ and ‘mathematical logic’ are both, indeed, ‘something’, so both prompt a question: who created God? Who set down the mathematical logic?
You might expect Hawking to say that we, the observers, are the answer. Where the buck stops. No need to ask who or what created us. We are here. Our presence ‘chooses’ that all the rest of it exists. No other argument is possible or needed.
Hawking does not use that argument. Not in his book, nor when he and I spoke in his office in November 2010. I mentioned the question he had posed in A Brief History of Time: ‘What is it that breathes fire into the equations and makes a universe for them to describe?’ Using top-down thinking, might the answer be – us?, I asked. His reply was ‘No.’
(2) The second argument relies on the idea of ‘model-dependent reality’. Those who present this argument point out that Hawking and Mlodinow have written that each of us has a personal model of the world that fits our life experience and attempts to make sense of it. Our models will in many ways be the same, but not in all ways, because our experiences are different. Hawking’s model does not have to include any experience of the presence and power of God. He has evidently had no experience of that and no reports of it from people he considers reliable. Why should he make it part of his model? He has no need of it.
On the other hand, for someone who has had experience of the presence and power of God, Hawking’s model is inadequate. Their model must include that experience. (And if you’ve already decided such experience can’t be ‘real’, then you’re already violating the tenets of ‘model-dependent reality’ and should leave this discussion.) Suppose that in addition to havi
ng experience of God you agree with Hawking’s science. Perhaps you are a physicist. Then your model will also have to include not only God but all the amazing findings and speculations of twentieth-and twenty-first-century scientists. Are you in trouble?
Luckily, a model that includes both belief in God and in science has not been ruled out by either A Brief History of Time or The Grand Design. It is possible and not crazy, at least according to many of Hawking’s colleagues, and both theists and atheists who have entered the debate. Read The Grand Design carefully and with an open mind, and you will probably agree that is so. We have, then, two different models, one with God and one without. According to ‘model-dependent reality’, it is meaningless even to ask whether one is more ‘real’ than the other, and inconsistent for Hawking to be so sure that his Godless-universe model represents ‘reality’.
You may be thinking that it is not appropriate to apply model-dependent reality to our personal world-views, but Hawking seems to think it is when he states:
Our brains interpret the input from our sensory organs by making a model of the outside world. We form mental concepts of our home, trees, other people, the electricity that flows from wall sockets, atoms, molecules and other universes. These mental concepts are the only reality we can know. There is no model-independent test of reality.22
Undeniably our models will include more than these physical attributes of the universe. They will, as we’ve said, include convictions of what is right and what is wrong. In an extreme case: are we required to respect a ‘model’ created through a lens of hatred, selfishness and prejudice? We know from Hawking’s public statements regarding human rights and politics that at least on a practical level he does not extend model-dependent reality to include model-dependent morality.
In My Mind I am Free
When Stephen Hawking and I were first discussing my plans for this book in November 2010, he asked me to be sure to include his latest ideas about eternal inflation and the observations he suggests could help verify it. You read about that in Chapter 19. His second request was that I not fail to mention his new television series that would be shown in the UK early in 2011. It is a three-part documentary called, in Britain, Stephen Hawking’s Universe (using the same title as an earlier series) and, in the USA, Into the Universe with Stephen Hawking.
This time it is not from a lecture hall or his office that Hawking invites us to join him on an adventure through time and space, but from the Hall of his college, Gonville and Caius. The long wooden tables have been pushed back against the walls. Hawking sits in his wheelchair, alone in the splendid wood-panelled room. His portrait can be seen on the wall along with portraits of other college luminaries of the past and present. In the familiar voice, he begins: ‘Hello. My name is Stephen Hawking: physicist, cosmologist and something of a dreamer. Although I cannot move, and I have to speak through a computer, in my mind I am free.’23 That proves to be abundantly correct as we voyage with him far out into the universe, in time and space, to encounter the wonders he knows or has good reason to believe are there, and into his own imagination to find the landscapes and creatures he thinks we might find. In this spectacularly filmed triptych, Hawking, and those responsible for the state-of-the-art computer animation and astronomy photography, succeed in evoking a chilling awareness of the enormous distances and numberless galaxies – the sheer, stupefying, inconceivable vastness of space and time.
Hawking doesn’t narrate the series himself. Even before his introductory sentence ends, the voice has seamlessly shifted to the voice of Benedict Cumberbatch, the actor who played the young Stephen Hawking in the film Hawking. Occasionally Hawking’s own voice comes back for a few seconds, and so does the scene in the Hall of Caius, just to remind us who’s really telling the tale.
For the first of the trilogy, the animators and Hawking have invented fantastic extraterrestrials, a few of whom he should shoot down immediately with his rocket-launcher if they ever appear in his office – never mind the Prime Directive. Although Hawking insists that the best place to look if we want to enquire about life in our universe is here at home, where there exists the only known life, he does lead us far beyond Earth and the solar system and our own galaxy. He tells us that there may be life in the cosmos so strange that we wouldn’t recognize it as life. And we hear, with a shudder, that it isn’t ‘what they’re like but what they can do that counts’: for instance, arrive in swarms of advanced-technology spacecraft and within a few seconds pirate all the energy of the sun by encasing it with mirrors, focusing that energy to create a wormhole. And yes, when it comes to wormholes, Hawking is back in that game, no matter how discouraging some of his recent statements have been about them. It might indeed be possible for a very advanced civilization to create one. Is all of this highly unlikely? Perhaps, but Hawking ends by reminding us of what we learned earlier in the show about our own improbable emergence here on Earth: ‘We only have to look at ourselves to know that extremely unlikely things can and do happen all the time.’24
In ‘Time Travel’, the second of the trilogy, Hawking admits to being ‘obsessed by time’. He is particularly curious about ‘how our whole cosmic story ends’. This segment is a tour-de-force overview of the possibility of time travel. Tiny wormholes through space and time constantly form and re-form, linking separate spaces and separate times. Could one be captured and enlarged many trillions of times and used as a time machine? Is travel to the past by this or any other means possible? Hawking has printed an invitation, copies of which he hopes might survive several thousand years, laid out champagne and delicious-looking food, and hung a banner, ‘Welcome, Reception for Future Time Travellers’. His invitation gives all the necessary information and coordinates required to find him and share this feast. No guests arrive. Perhaps none of the invitations survived long enough, but in a Cambridge college, at least one or two of them probably would. Because no one responds to his invitation, and for other reasons, such as a ‘fundamental rule that governs the entire universe’ that cause happens before effect, unsolvable paradoxes, and the inevitable radiation feedback that would destroy a wormhole before you could use it, Hawking concludes that we cannot travel to the past. But we can to the future, and we needn’t depend on wormholes. Einstein realized that time doesn’t flow at the same rate everywhere, and it’s a well-established fact that he was right. Matter drags on time, slowing it down, and that means a massive body can serve as a time machine. A spacecraft flying near the event horizon of a super-massive black hole, with skilful enough navigation and sufficient speed not to fall in, would make a noticeable jump forward in time. After about five years (in your personal time) at the black hole, you could find that ten years had passed on Earth. Travelling near the speed of light would work much better, though the same slowing of time that makes this a quicker way to get to the future also makes it impossible to travel at or above the speed of light. Passengers travelling near light speed (in a wonderfully conceived train that must circumnavigate the Earth seven times a second) could return after only a week measured in their own personal time, to find the world had moved forward by a hundred years.
The third segment of the trilogy is a genuine climax to the series. First, Hawking takes us to the early universe to observe the Big Bang. He admits that it would all have been completely dark, because light didn’t exist yet – so you couldn’t actually see it. Space didn’t exist either. There was no ‘outside’ this event from which to view it. ‘All that there was was inside.’25 We journey through the inflation era, witness the annihilation of matter and antimatter with the whole future of the universe hanging on there being just a minuscule bit more matter than antimatter, and learn the enormous significance of the force of gravity again and again in creating the universe we know. We see Wheeler’s democracy vividly demonstrated as a load of ball-bearings roll through the doors into the Hall of Caius. Animation takes over to show them all perfectly equidistant from one another, forming a gridlock that would never have yielded
to make ‘our’ universe. But remove just a handful of the ball bearings, one here, one there, from the perfect pattern, and gravity gets a foothold – another example, Hawking points out, of how imperfection is absolutely necessary in our universe. Eventually we do get to the universe as we know it, and beyond. Hawking takes us into the future, and he is a truly amazing ‘futurist’. His plea is eloquent in support of colonizing other planets, and his vision for Earth harrowing. He is still as concerned as he was in his youth about the hazard of nuclear weapons – ‘We are clever enough to design such things, but I’m not sure we are clever enough not to use them’26 – but some of the other possibilities are even more likely to cause nightmares. He also admits that there are staggering obstacles we will encounter in finding another home in the universe.
What about the question of how our whole cosmic story ends? ‘The fate of the universe,’ he tells us, ‘depends on how dark energy behaves.’27 Is it increasing? Will it continue to push space apart, driving the expansion? Will all the particles eventually be so far apart that nothing at all can happen? Or might dark energy’s strength diminish, allowing gravity to pull everything together again in a Big Crunch? We don’t know. That end is a very long way off. Hawking says that on one of his trips to Japan he was requested not to mention the fate of the universe lest it upset the stock market, but he thinks it would be premature to sell up. Hawking’s suggestion for survival at that extremely distant time is that we might find out how to travel to another universe. We have about thirty billion years to work out how to do that.
Stephen Hawking, His Life and Work Page 35
