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Sitting in the shade of a tree on the grounds of the Sydney Observatory, not far from the Harbour Bridge, the physicist and writer Paul Davies is reflecting on the three great “origin” problems that confront modern science. “There’s the origin of the universe, the origin of life and the origin of consciousness,” he says in a north London accent that has survived decades spent living in Australia and the US.
Of the three, he says, the origin of the universe has been the simplest to crack. “We have really made a lot of progress in that. I think we’ve solved it.” The Big Bang theory, according to which the universe has been expanding out of an extremely hot and dense state for the past 13.8bn years, is now widely supported among scientists.
Understanding the origin of the mind, meanwhile, seems to Davies a hopeless cause. “We’ll never go anywhere with that. How do you get thoughts, feelings and qualia out of atoms, molecules, neurones, electrical circuits? We don’t even know how to begin.”
But the third problem is just right for study – residing in the zone between impossible and already solved. “The origin of life seems to me to be midway between the ease of the origin of the universe and the toughness of the origin of consciousness. I think it’s something we might actually make progress out of.”
The 67-year-old Davies is one of the most prominent science communicators of our time. He heads the Beyond Center for Fundamental Concepts in Science at Arizona State University, which aims to extend the boundaries of research beyond conventional subject categories and, according to its website, to “present science to the public as a key component of our culture and of significance to all humanity”. Fittingly, he has spent much of his professional life writing and talking about the big questions that occupy the disputed territory between science, religion and philosophy. The 29 books he has published since 1974 cover topics ranging from the nature of time to the search for alien intelligence and why the universe seems so perfectly tuned for life.
These days, it is the origin-of-life question that is gripping his attention. “The real challenge,” he says, “and we’re stuck at step zero, is what is this thing called life?” Although he’s always remained a physicist at heart, understanding the place of existence in the universe has been an enduring passion. That interest has been given fresh impetus by his work with Sara Imari Walker, an associate professor at the Beyond Center. For them, the division between life and non-life isn’t simply a question of chemistry – it’s about the way living things can store and process information. If you conceptualise life in this way, then understanding the physical architecture becomes a secondary concern.
To illustrate this point, imagine trying to understand how the Windows operating system on a computer works. Taking the back off and studying the arrangement of copper, silicon and plastic in the box isn’t going to get you very far, but studying the machine code and the software would take you much closer to an answer. Similarly, studying molecules in a test tube is “sort of somehow missing the point”, says Davies. “That’s the substrate of life. Obviously you need to know that, just like you can’t have Windows without the silicon and the copper and the plastic and all the rest of it. But that doesn’t explain how Windows works. We’re after the software side, that’s our project. We’re happy to leave the hardware people to beaver away.”
From an early age, Davies has pondered the deep questions of the universe from this kind of theoretical perspective. Growing up in postwar London, he would lie awake at night wondering whether space had an end, and how free will was possible if the brain was built of atoms. “From a very early age I was gripped by the idea that not everything in the world was visible before our eyes.”
He felt that theoretical physics, the branch of physics that explores the rules underpinning the natural world, offered the quickest route to addressing these big topics. “I just wanted to fast-track it. The joy of theoretical physics is that when you push into the unknown you will see coherent patterns, a rational scheme.” His PhD thesis looked at how quantum theory works when space and time are curved by gravity, and for a while this was his primary research field.
“Paul was one of the great pioneers of this subject early on,” says James Hartle, emeritus professor of physics at the University of California, whose own research involves the application of Albert Einstein’s general theory of relativity to cosmology. “He made important contributions in this area.” One notable example is the Bunch-Davies state, which is used to explain fluctuations in the cosmic background radiation left over from the Big Bang.
Yet Davies was never going to maintain a narrow focus. In the 1970s and 1980s, in parallel with his academic work, he began a writing career that took him into much murkier territory.
The titles of his books – such as God and the New Physics, The Cosmic Blueprint and The Mind of God – advertise his inclination towards pondering the origins and form of the universe. His willingness to broach these topics has sometimes raised eyebrows. In 2007, for example, a group of scientists strongly criticised an opinion piece he published in The New York Times in which he declared that science had its own “faith-based belief system”, in that scientists assume nature is ordered in a rational and intelligible way. He tells me that his position on these questions is often misunderstood and that his critics in this case “obviously didn’t read the article … If your notion of God is as somehow meddling in the mechanism of the world, then that God has had a rather poor track record and is now consigned to the dustbin of history.
“But my challenge to both scientists and theologians is do we just stop at the laws of physics, and accept we will never know why they are as they are? Or do we say we can extend scientific inquiry to try to understand why they are as they are?”
One of his colleagues at Arizona State, the theoretical physicist and prominent atheist Lawrence Krauss, says Davies is “more than happy to jump into an area that he otherwise doesn’t have background in”. Doing this can leave you vulnerable to being completely wrong – but Krauss believes there is nothing wrong with that. “I wouldn’t be surprised if Paul is completely wrong in a number of things, but asking the questions provokes new lines of inquiry.”
One of those longstanding lines of inquiry has been the likelihood of life existing elsewhere in the universe. Davies chairs the Seti Post-Detection Task Group of the International Academy of Astronautics, a group whose purpose is to prepare for the day we detect a signal from ET.
But even he admits that while he would like to believe there’s a deep principle in nature that drives matter to evolve into life, there is “nothing in physics or chemistry or anything we’ve discovered that suggests fast-tracking from matter to life is inevitable”. Given this, he has come to suspect that the steps required for life to emerge from non-living matter may have occurred just once. “When you ask how many places in the universe that precise sequence of events will have taken place, it’s very easy to argue that it would be only once,” he says. “I think we are probably alone. And that would be sad, wouldn’t it?”
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