Unpublished, 05 January 2015
The greatest story of our time may also be the greatest mistake. This is the story of our universe from the Big Bang to now with its bizarre, Dickensian cast of characters – black holes, tiny vibrating strings, the warped space-time continuum, trillions of companion universes and particles that wink in and out of existence.
It is the story told by a long list of officially accredited geniuses from Isaac Newton to Stephen Hawking. It is also the story that is retold daily in popular science fiction from Star Trek to the latest Hollywood sci-fi blockbuster Interstellar. Thanks to the movies, the physicist standing in front of a vast blackboard covered in equations became our age’s symbol of genius. The universe is weird, the TV shows and films tell us, and almost anything can happen.
But it is a story that many now believe is pointless, wrong and riddled with wishful thinking and superstition.
“Stephen Hawking,” says philosopher Roberto Mangabeira Unger, “is not part of the solution, he is part of the problem.”
The equations on the blackboard may be the problem. Mathematics, the language of science, may have misled the scientists.
“The idea,” says physicist Lee Smolin, “that the truth about nature can be wrestled from pure thought through mathematics is overdone… The idea that mathematics is prophetic and that mathematical structure and beauty are a clue to how nature ultimately works is just wrong.”
And in an explosive essay published last week in the science journal Nature astrophysicists George Ellis and Joe Silk say that the wild claims of theoretical physicists are threatening the authority of science itself.
“This battle for the heart and soul of physics,” they write, “is opening up at a time when scientific results — in topics from climate change to the theory of evolution — are being questioned by some politicians and religious fundamentalists. Potential damage to public confidence in science and to the nature of fundamental physics needs to be contained by deeper dialogue between scientists and philosophers….The imprimatur of science should be awarded only to a theory that is testable. Only then can we defend science from attack.”
Unger and Smolin have also just gone into print with a monumental book – The Singular Universe and the Reality of Time – which systematically takes apart contemporary physics and exposes much of it as, in Unger’s words, “an inferno of allegorical fabrication.” The book says it is time to return to real science which is tested against nature rather than constructed out of mathematics. Physics should no longer be seen as the ultimate science, underwriting all others. The true queen of the sciences should be history – the biography of the cosmos.
So when did it all go so horribly wrong? The critics would say in 1984 when a new idea – superstrings – suddenly seemed to offer physicists an escape from a dead end left behind by Einstein.
The physicist Brian Greene describes superstring theory as “a sweeping movement that inspired thousands of physicists worldwide to drop their research in progress and chase Einstein’s long-sought dream of a unified theory. The field was young, the terrain fertile and the atmosphere electric.”
Superstrings are tiny loops at the heart of every particle. The way they vibrate determines what the particle is and how it behaves. If they existed then they could solve the mystery left behind by Einstein – how to unite all the forces in the universe in a single theory. They might crack the most embarrassing problem of all. Einstein’s relativity, which describes the behaviour of large objects like planets, and quantum mechanics, which describes the behaviour of very small objects, are the two great achievements of twentieth century science. They both seem to be true, but, embarrassingly, they contradict each other. Perhaps superstrings would be the solution.
Well, in a way, it worked. Superstrings produced some of the most complex and, to its supporters, beautiful mathematics ever devised. It even, in theory, solved all the problems. But only in theory because to make the theory work, scientists had to invent a world with more than three dimensions and millions of other universes – the so-called ‘multiverse’. Since the strings themselves are too small for us to see, the additional dimensions are locked away beyond the gaze of our most powerful instruments and the other universes are completely undetectable. In other words, no experiment or observation of these things would be possible; to believe the solutions of string theory you had to believe in the maths alone. And that’s where it all starts to fall apart.
“As we see it,” write Ellis and Silk about this development, “theoretical physics risks becoming a no-man’s-land between mathematics, physics and philosophy that does not truly meet the requirements of any.”
To the critics, the idea that we should believe solely in the mathematics is, first, a betrayal of science and, secondly, a demonstrable absurdity. It is a betrayal because science has always been the development of hypotheses in the mind or in the lab which are then tested against what we can find in nature – any theory must be falsifiable by nature or it is metaphysics, faith or superstition.
Outside physics, this definition is intact and the dangers of relying on maths are obvious. In climate science, for example, mathematical models have repeatedly been proved wrong – most spectacularly in their failure to predict the pause in global warming over the last two decades. By the rigorous and effective standard of testing against nature and falsifiability, superstring theory cannot be science.
Relaying on mathematics is demonstrably absurd because it makes two unprovable assumptions – that maths can accurately describe the universe and, even if that is true, that our maths at this particular moment is good enough to do it.
Faced with these problems defenders of the faith – like the physicist Sean Carroll – have argued that it is time we loosened our definition of science to include purely mathematical proofs. This is a serious – indeed, a reckless – escalation that turns what was a skirmish into outright war in which there will be many more casualities than just superstring theory.
Unger and Smolin’s book, for example, swings a wrecking ball through almost the whole of contemporary physics from Einstein onwards. They insist on three principles – there is only one universe, time is real and mathematics is limited – that would, if accepted, not only cause a revolution in physics but in the whole of science. Most importantly, they would displace physics as the queen of the sciences. Instead the real, experimentally and observationally demonstrable, history of the cosmos would become science’s new gold standard.
The multiverse, in particular, comes in for a kicking.
“The multiverse,” says Unger, “treats these imaginary worlds as if they were real worlds. That’s the sleight of hand of particle physics.” And in popular sci-fi – “As the fabricated universes become real, the actual universe becomes less real.”
The multiverse has, in fact, been used three times to plug a gap – in the inflationary theory of the universe, in quantum theory and in string theory. Each time it is an attempt to explain why our universe just happens to be the way it is. But, surely, this is cheating. If, say Unger and Smolin, our theories don’t work, then we should ditch the theories, not invent imaginary and forever undetectable worlds.
Bizarrely, these worlds are invented by people who are forced to admit that their theories can’t actually work and full accounts of the universe. The conditions at the heart of a ‘singularity’ – in the Big Bang or in black holes – are said to lie beyond the laws of physics, so, in other words, the supposedly unchanging laws of physics only work by encompassing their own limitations.
If, as Unger and Smolin insist, time is real and not simply an aspect of space or of our perceptions, then the laws of physics begin to look even less solid. If everything is subject to time and, therefore, change, then these laws can evolve. They suggest the idea that these laws are eternally fixed is a supersition caused by mathematics – all the insights of maths are timeless and maths is only a human creation. In fact, two of the greatest physicists of all time – Richard Feynman and Paul Dirac – both accepted the possibility that the laws of physics evolve through time. Yet eternal, immutable physical laws, somehow detached from our physical universe, remain one of the primary superstitions of our age.
Even the cherished Big Bang may not survive the return of real time. There may, instead, have been a Big Squeeze, a moment at which our universe shrank and then expanded again. Time did not begin, as the physicists have been telling us, at the Big Bang, it passed serenely on through the Big Squeeze, as did our own universe.
But, I ask Smolin, how many people now accept the case of the critics?
“I would divide my community into two parts,” he says, “the people who try to think carefully about where we are, where we are going and why we have not made so much progress and everybody else. There are a remarkable number of people in the first group who at least partly agree with us. But there are a number of very deep thinkers who disagree. We are a minority but my sense is that a lot of people haven’t thought it through.”
Does any of this matter to you? All of it does. The rise of physics to the throne of ultimate science since the early twentieth century has, inevitably, affected ordinary life with its assumptions and not just in sci-fi. For example, contemporary determinism – the idea that everything that happens is inevitable and that our free will is an illusion – springs from twentieth century physics and has, most recently, infected neuroscience.
Perhaps more damagingly, the idea that the human mind, unaided except by mathematics, can encompass the universe has downgraded nature and deluded us into thinking we can do anything. We can’t. Nature – human or otherwise – is the only standard by which we or our ideas can be tested. The rest is just chalk on a blackboard.