The Emperor's New Lab Coat

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A spectrum against a black background.

British physics is in a mess, reportedly. At the end of 2007 it became apparent that there was a funding shortfall of £80m for fundamental research. £80m is a lot of money from the standpoint of any individual, but as part of a total budget of £600m it seems like a swingeing blow. After about two decades of contraction within universities, which have seen numerous physics departments (especially the smaller ones) close as part of a deliberate policy of 'research concentration', one would have thought that the dead wood would have been cleared and any further cuts would have been in into the living tree of physics research itself. The UK nevertheless now stands to lose access to the eight metre Gemini telescopes, and support for international particle physics projects like the International Linear Collider will now have to be reconsidered if not withdrawn.

Ask a physicist why this decimation has now occurred and, chances are, you'll be told that it's a result of a canker from the grass roots eventually reaching the head of the tree. For decades physics has been a Cinderella subject at A-level, taken by far too few and in dwindling numbers. Fewer physics graduates imply fewer professional physicists and, coupled with the lack of regard or even awareness of the discipline, this has eventually led to an inevitable decline in research in the UK.

This is probably true, but it certainly isn't the whole picture. The blame cannot wholly be laid at the feet of crappy secondary school physics teachers. You don't have to be a physicist to grasp the grass-roots argument for better teaching in our schools, but you do have to be a scientist to notice that a different kind of rot set in at the crown of the tree as the same time as the roots were withering. It's been noticed by people like me, who trained as a research chemist and who understands how science is done. We are in fact more than a little uncertain about whether physicists have, for the past 30-odd years, been doing 'science' as the rest of us know it.

Tied up with String

Has that uncertainty been assuaged by any of my recent reading material? Quite the opposite, as it happens. Take for instance, a book by Lee Smolin: The Trouble with Physics. Dr. Smolin heads up an institute dedicated to theoretical physics, and has turn an unusually critical eye upon what his colleagues have been up to over this period. He observes that, more so than any other science, physics is lead by theorists and that physical experiment catches up much later in the day. However, he also points out that once about every ten years, a theoretical prediction is verified, even in the ultra-high-tech world of particle physics where an experiment takes years or even decades, and millions of dollars, to construct. This is, after all, how we distinguish real scientific theory, such as the Origin of Species, from pseudoscience such as Intelligent Design, in that it makes testable predictions. For instance, Einstein's theory of General Relativity wasn't truly accepted until an eclipse in 1919, when his prediction that gravity would bend light waves was shown to be true. Similarly, the unification of the electromagnetic and weak nuclear forces was shown to be true in 1983 when the existence of the relevant charge carrying particles was finally confirmed, thanks to the building of gigantic accelerators that could accelerate particles to close to the speed of light before smashing them into each other. 'It all comes out in the wash', as my grandmother used to say. It just depends upon how big a washing machine you can build.

Smolin sees a problem in that for the past 30 years the principal pursuit of theoretical physicists 'string theory ' has produced no solid proposition that can be tested in a laboratory or outside it for that matter. In fact, since string theory itself has only been around for 30-odd years, this means that it hasn't really produced any testable predictions, period. Does this actually qualify string theory as a science? Smolin thinks not. The situation isn't likely to get any better, even with the Large Hadron Collider about to power up any month now. This immense - and immensely ambitious - machine won't have even a billionth of the power needed to probe the kinds of minute distances at which string theory is said to operate. The 'washing machine' would have to be the size of the solar system to deal with this load of smalls.

String theory, in case you're interested, started out as an attempt to come up with a unified approach to the kind of physics that occurs at both the infinite and infinitesimal scales. When we talk about cosmological events, the force that dominates this landscape is gravity, and Einstein's General Relativity works very well indeed. Where it comes unravelled is at the atomic level where quantum effects predominate. String theory was an attempt to reconcile the macroscopic and microscopic. All of the fundamental particles that make up our universe interact through one of four forces, gravity being the fourth and weakest force. These forces are themselves carried by particles and the particle that supposedly mediates gravity, the graviton, drops out of string theory almost as a side product. It's a classic example of serendipity in science.

Too Many Loose Ends

However, it's fair to say that one is obliged to make a rather more sober and holistic assessment of string theory before proclaiming it the best thing since Einstein. A yardstick by which the power of any scientific theory can be assessed is provided by comparing what it explains with the number of assumptions it makes. Arguably, by this reckoning, Charles Darwin had the single best idea of anyone when he came up with natural selection. A billion well-adapted species are explained by simply one postulate: the existence of inherited characteristics to genes to us 21st Century folk.

String theory, in stark contrast, assumes a good deal more than it explains. Firstly, it suggests that all matter is made of infinitesimally small strings of an unknown substance. The reason we can't see them is because their scale is such that it takes unimaginably high energies to probe such small distances, about 10-35 metres. This is about a hundred billion billion times smaller than an atomic nucleus, already about as small as a solid object gets. If you actually managed to get your head around this idea, string theory then proposes that there are not three spatial dimensions in the universe but ten. Moreover, it points out that the reason why we can't perceive these extra dimensions is because they are circular in form and wrapped up so small that nothing can make them out, in a tangled structure known as a Calabi-Yau manifold. The properties of the fundamental subatomic particles, such as mass and electrical charge, are simple manifestations of the vibrations of these strings.

This would be all well and good if there were some convincing experimental evidence for this kind of thinking, but there isn't. String theory even has a hard-enough job of predicting what's already gone before: there are no calculations for the fundamental particle masses, for instance. Nor are there likely to be any in the offing. Most scientific theories undergo their own kind of evolution in which ideas are refined until they consist of single well-understood and refutable propositions. Harking back to Darwin, the idea of a gene was refined by Mendel who showed that inherited characteristics operated as pairs rather than singly, and eventually we ended up with the DNA molecule. String theory, in contrast, appears to be degenerating into a primordial ooze of ideas: the latest conclusion is that there is not one string theory with a set of testable and concrete propositions but 10500. That's right; a googol googol googol googol googol different theories, each with their own set of physical laws and families of fundamental particles! And none of them any better evolved to explain reality than any of the others.

Blurring the Goal Posts

You would think that at this point that this kind of reasoning would now be defensible only as a (rather over-extended) exercise in reductio ad absurdum. Well, this is where the string theorists pull their rabbit from the hat. Instead of adhering to time-honoured scientific convention by insisting that their theory actually converges with observable reality at some point, they invoke the anthropic principle. This interpretation proposes that, rarther like cosmological parish councils, the universe exists along with billions of other universes each with their own parochial sets of physical laws, each of which differ, and that a different version of string theory operates in each. We just happen to be in the universe where our version of the theory allows life to evolve and thrive. It's just that we haven't got around to investigating that particular version yet. Funny how the holes in a cat's fur are always just where the eyes are, isn't it?

It doesn't take an Einstein or even a Smolin to recognise that the string theorists have monumentally mistaken mathematical cleverness for insight and beauty for truth. In both case they are now in danger of forsaking the latter altogether for the sake of the former. To be sure, the theory is mathematically beautiful, and some extremely bright people have contributed some very powerful and novel techniques to pure mathematics solely as a result of the work they have done on string theory. But mathematical utility or even beauty don't imply physical truth. More often than not reality is disobligingly messy and inelegant: there is no easily soluble set of equations for dealing with turbulent flow in liquids, for example, but it obviously happens.

Moreover science, when done properly, doesn't just rest on theory. It's founded on a three-legged stool of theory, data and 'narrative': the story of how science really gets done in the real world. Hack off two legs as redundant, and the enterprise becomes very wobbly as string theory is now finding out to its cost. There has been a lot of twaddle in recent years talked about physicists 'knowing the mind of God' as if they alone had the ability to uncover and comprehend the ultimate truth, whatever that might turn out to be. This is really the culmination of an increasingly imperious trend in unjustified self-regard. Many physicists have for a long time arrogated a privileged role among other scientists, but exclusively pissing about with esoteric equations for 30 years isn't science whatever the theorists might like you (and each other) to believe: the Emperor's tailors have simply fashioned him a new lab coat. The danger is that this jaundiced perception of one branch of physics becomes the popular perception of the whole science, alienating the experimentalists, other scientists, intelligent laypeople and eager young minds who should be taking it up in school in the first place. I'm afraid that this might have already taken place to some degree, explaining why British physics, at least, is now having to raid the family piggy bank for coppers, having few champions outside the science who can still relate to its value, but plenty of detractors who rue the cost.

Ironically, the saviour of physics might well turn out to be the very project that has come to symbolise big-budget and elitist science: the LHC. This machine has been many years in the making and, in the context of comments like the one about the 'mind of God', one might be forgiven for thinking that its champions were trying to build the modern equivalent of the Tower of Babel under the Franco-Suisse countryside. I expect and hope that when it finally gets running and produces some meaningful findings there will be more than a few surprises, especially in what it doesn't discover as much as what it does. If there is no evidence of higher dimensions, supersymmetry or even the much-vaunted Higgs boson, the only tower that will be struck down is the whole creaky house of cards that theoretical physics has become.

Such a victory for common sense will be sweet at first but leave a very bitter aftertaste. Hundreds of years of people's lives will have been wasted chasing theoretical mirages. Careers will be ruined for many well-meaning but misguided people. When I used to feel smug about being a scientist - which wasn't often, it being a very uncool profession - it was for the sole reason that I though the humanities had a monopoly on the production and distribution of intellectual twaddle. However, I am forced to conclude that, for now, some very important areas of science now resemble post-modernist philosophy more than anything else, where any interpretation of reality is held to be as valid as any other. The language used might be mathematics instead of (broken) French, but both process and end result are the same: the role of external evidence is subjugated to linguistic (or mathematic) flair, and nobody outside the discipline knows what the hell anybody inside it is talking about, and even its initiates can't agree as to whether it means anything. Any emerging truth appears to be constructed entirely within discourse.

Science up to now has been a good friend to me because it allowed me to analyse difficult issues in the cold, hard, light of day. Not any more: if Smolin is right it looks like that my intellectual world has been turned upside-down. However that would imply that dawn now breaks from a different quarter and those of us who think that there's an ultimate truth of some kind can find it elsewhere, such as in philosophy. Theoretical physics now seems hell-bent on following philosophy into incomprehensible irrelevance, and along with many others I now face the grim prospect that, for the time being anyway, the sun has given up rising altogether.

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