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Culture, history and society

Culture, history and society

The life and times of a popular scientist

01 Sep 2002

From his beginnings as a theoretical physicist, Paul Davies has branched out to write about cosmology, religion and the origins of life. Peter Rodgers catches up with him.

Widely read

According to his website, Paul Davies currently averages several television and radio appearances per week in various countries around the world. However, when he meets Physics World at 11.00 a.m. on a Thursday in early August he has already completed three radio interviews that morning and has more lined up for the afternoon. And over the next few days he will be quoted by newspapers as diverse as The Times and the Sun.

The reason why Davies is so in demand by the media, even by his own standards, is that he has published a paper in Nature that morning and is giving a public lecture about Paul Dirac in Bristol that afternoon. In what is perhaps a cosmic coincidence, the Nature paper is about the possibility that the speed of light has changed over the history of the universe, while his lecture will cover Dirac’s ideas about big numbers and the related idea – due to Robert Dicke – that “now” might actually be a special time in the history of the universe. The real coincidence is that the Nature paper is appearing 100 years to the day since Dirac was born in Bristol.

When Davies was a bright young theoretical physicist – he was appointed professor of theoretical physics by the University of Newcastle-upon-Tyne at the age of 34 – one of his ambitions was to explain why the fine-structure constant, α, has a value of 1/137. The constant – which is defined as α = e2/h-bar c, where e is the charge on the electron, h-bar is Planck’s constant divided by 2(pi) and c is the speed of light in vacuum – is a dimensionless number that determines the strength of interactions between light and matter.

“When I was a PhD student I was always fascinated by the value of α and thought that physics should be able to explain this value,” says Davies. “I thought my life ambition would be to write a paper that could explain this. But in the 1970s and 1980s it became clear that α was not fundamental – rather it was a low-energy limit of a more complicated state of affairs, so it probably would not come out of a simple theory. Now if it turns out that α is varying with time, it is doubly mysterious.”

A lot has happened to Davies since his first interactions with α. In addition to publishing over 100 research papers, he has authored more than 25 books, written over 1000 newspaper articles and given countless public lectures on physics and cosmology. Most recently he moved from Adelaide to Sydney – having emigrated from England to Australia in 1990 – to join the Australian Centre for Astrobiology at Macquarie University on a part-time basis.

Cosmic background

So how did Davies – who was born in London in 1946 – become interested in physics and eventually astrobiology? “When I was growing up in the 1950s, suburban London was actually pretty dull,” he recalls. “There wasn’t a lot of excitement, but I found that I could go into the garden and look up at the stars and it was a wonderland.” It was, he says, a form of escapism. “I was captivated by notions of subatomic particles, problems about whether space was finite or infinite, and what the stars were made of. From the age of six or seven I can remember asking these questions.”

By the age of 12 he was developing photographs and at 14 he built his own telescope. It was then that he had his first encounter with Margaret Thatcher – then his local MP and later the notoriously anti-university prime minister who was partly responsible for Davies emigrating. Thatcher presented the young Davies with a signed atlas of the stars at a school-prize day. Over 30 years later Davies got Thatcher to re-sign the atlas when she was part of the jury that awarded him the lucrative Templeton Prize for progress in religion in 1995.

Davies did a degree in physics at University College London and stayed on to do a PhD. Fred Hoyle was the external examiner for his thesis and invited Davies to work at the Institute of Astronomy in Cambridge where, at the time, “Stephen Hawking was just the guy in the wheelchair and Martin Rees was just a postdoc down the corridor”.

Davies then spent eight years as a lecturer in mathematics at Kings College London before moving to Newcastle, where he established a large research group working on quantum gravity, cosmology and quantum field theory in curved space-times. Newcastle also had a very strong geophysics research programme and Davies says that he can trace his current interests in astrobiology and the origins of life to his time there. His own group flourished for a number of years but it became “a victim of the Thatcher cuts” and Davies decided to move to Australia to become professor of mathematical physics at the University of Adelaide.

The university subsequently created the special position of professor of natural philosophy for Davies, but in 1996 he decided to resign for various personal and professional reasons. He retained visiting professorships at Imperial College in London and the University of Queensland, and recently accepted his current non-teaching post – again as professor of natural philosophy – at Macquarie.

Books books books

Despite his prodigious output, Davies says that he was not a natural writer or communicator when he was young and that he scraped through English O-level. However, he wrote up some of his PhD research for Physics Bulletin – the forerunner of Physics World – and it was read by a publisher who asked him to write a book. “It was something I hadn’t considered before but I decided to give it a go.” And so it was that his first book, The Physics of Time Asymmetry, was published in 1974.

Davies was then approached by Cambridge University Press to write a student textbook – Space and Time in the Modern Universe – and then by a trade publisher to write a book for the general public. “After The Runaway Universe was published in 1978 I just kept doing it,” recalls Davies. “But it was a lonely experience in the early days because a lot of my colleagues thought that a self-respecting academic should not be writing popular books because it would be damaging to one’s career. Writing journal articles was fine; writing textbooks was okay but was best left to later in your career; and writing a popular book was a thoroughly dreadful thing to do.” Davies recalls that “writing was like a guilty secret – I used to slope off home and write popular books and hope that no-one would notice”.

But that all changed in the 1980s and Davies found his colleagues in Newcastle more accommodating: “They felt it was no bad thing to have a few books to make physics seem exciting to young people”. And then Stephen Hawking published A Brief History of Time and the rest is, well, history. “People thought ‘If it’s okay for Hawking, it is okay for me’ “, he recalls. “And now it’s not only okay to write popular books – it is almost an obligation.” Indeed formal recognition for Davies’ work has recently arrived in the form of the Kelvin Prize from the Institute of Physics and the Michael Faraday Award from the Royal Society.

Davies does not know which of his books have sold the most copies but says that the two with God in the title – The Mind Of God and God and the New Physics – seem to be the most popular. However, he has very different views on them. “I wrote God and the New Physics in 1983 and never regarded it as a terribly credible attempt at bridging the divide between science and religion – but it is still selling now 20 years on – somewhat to my embarrassment.” Davies believes that The Mind Of God, which he wrote in 1992, is a much more serious attempt to tackle the interfaces between science and religion.

His other personal favourites are About Time and The Fifth Miracle, which marked his first serious foray into the search for the origins of life and his new subject of astrobiology. They also involved learning a lot of chemistry and biology. “Although it involved a steep learning curve, I feel that I made a contribution to the subject,” says Davies. He is particularly proud that he stuck his neck out in The Fifth Miracle in two ways – one was to say that life “kind of hopped from Mars to Earth, or vice versa”, and the other was “some deeper stuff about what it takes for life to get started in the first place”. At first, says Davies, everybody thought his idea that Earth and Mars are not biologically isolated was crazy but now it is “almost the party line”.

Religion and science

So how did Davies become interested in religion? “I am not a conventionally religious person,” he says, “but I did find in my scientific work that I was looking at age-old questions about existence that for years have been the province of philosophy and theology – the origin of the universe, the nature of consciousness, the nature of time, the end of the universe and so on. Inevitably I started to reflect on such questions as where do the laws of physics come from, why are they the way they are, why do they seem so successful and ingenious, and how is it that they are consistent with the emergence of conscious beings who reflect upon them?”

Although Davies does not believe in miracles, he does believe that there is some reason for life and the universe “My own theological position, if I can put it like that, is that I don’t want miracles. Rather I think that science gives us the best account we have of the physical world, and through science we can come to understand that the physical world is extraordinarily ingenious,” he explains. “However, I don’t believe that the underlying laws of physics that we know and love are just a bunch of marvels that come from nowhere for no reason – I think there are reasons for why the world is as it is. I would even go so far as to think that these reasons include the existence of conscious beings – i.e. life and mind, but not necessarily humans and DNA.”

Davies is keen to know if “multiverse” explanations of these “anthropic” coincidences are credible. Indeed can we even quantify the credibility of them? In the multiverse explanation there is a vast multiplicity of parallel worlds in which all possible laws of physics exist – in some worlds the laws are same but the fundamental constants are slightly different, in others the laws themselves are different, and in some worlds there are completely different mathematical structures. And in a tiny subset of these worlds the laws and conditions are just right for life to emerge.

“The organisms in this universe might then look at these apparently contrived instances of the laws and think that it has all been designed with them in mind,” says Davies, “but of course they’re just the winners in a cosmic lottery.” But is there any real difference, Davies asks, “between an explanation that invokes an infinite number of universes in order to conclude something about this one universe and an old-fashioned theistic explanation that there’s an infinite unseen god who just plucks a judicious universe from a infinite set of alternatives?”. His hunch is that they are the same, but he is keen to start a research programme that uses algorithmic information theory to address these questions.

A life in the day

So what is it like being Paul Davies? “There is no typical day, week or month,” he says. “My life is a mixture of academic research, writing, and media activities and travelling.” Davies makes three or four long trips per year and usually works “on the run”.

Although Davies says that he has “reinvented himself as an astrobiologist”, his Nature paper marks a return to his physics roots. Recent astronomical observations have suggested that the fine-structure constant, α, is increasing, which means that the charge on the electron is also increasing or that the speed of light is decreasing (see Physics World October 2001 pp26-27). By looking at the thermodynamics of black holes Davies and two colleagues – Tamara Davis and Charles Lineweaver – find that the charge on the electron cannot be increasing, otherwise the entropy of black holes would decrease and violate the second law of thermodynamics (2002 Nature 418 602).

Initially Davies did not want to believe that α was changing: “I was very dubious at first because it seems very ugly from the point of view of theoretical physics.” To begin with, the observations were at the limits of detectability, he says, but the data have improved dramatically and the idea now has to be taken seriously. However, it is too early to say what this will mean for the whole structure of physics: “Whether this is a paradigm shift or whether we will just have to tinker with the existing structure of theoretical physics, it is too soon to say. Even if we have to allow the speed of light to vary, it doesn’t mean that we will have to completely abandon the theory of relativity – it would mean that it would be good under almost all circumstances and we could embed it in some theory that is not too different from what we understand.”

The use of the second law of thermodynamics in cosmological situations has long been a hallmark of Davies’ research. “For most of my career I have tangled with cases where it looked like the second law was being threatened,” he explains. “People often ask what is the big deal about the second law? I think that really it transcends physics – it says that you cannot get something for nothing. It is also a very good way of testing physical theories – if they look as if they are going to clash with the second law it is usually a sign that something has gone wrong.”

And what ambitions does Davies have left? “Much of my frustrated ambition is not to do with popularizing science but with doing science. I really would like to understand the origins of life – how does non-life becomes life? What is the physics underlying this?” Davies says that life is all about information, and he has a hunch that quantum information processes play a role – but he admits that it is a “slightly crazy hunch”.

Davies’ other ambition is to make a major television series. “Physics needs and deserves a major high-profile TV series,” he says. “I would like to do for physics what David Attenborough has done for biology – something that has gravitas, not something that is jokey and light-hearted. I would like to make a Life on Earth for physics.” Like the young schoolboy looking at the night-sky over London, his motto might be watch this space.

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