The Next Philosophy

Science has helped answer some of the fundamental questions of our existence. Yet, as Paul Davies reminds us, we are still a long way from solving perhaps the most intriguing mystery of all: Are we alone in the universe?

by Marianna Krejci-Papa

Celebrated cosmologist, physicist, and award-winning author Paul Davies has made a career of tackling life's most profound questions, enticing us over the past three decades to consider the universe in new ways. As a pioneer in the burgeoning field of astrobiology, he continues to push the frontiers of science, questioning the likelihood of the existence of intelligent life beyond the confines of our planet. While modern science has given us impressive means of exploring this possibility- exemplified by the highly sensitive radio telescopes developed by the Search for Extraterrestrial Intelligence (SETI) Institute- Davies sees the search for extraterrestrial life as an extension of the age-old work of theologians and philosophers. Science, like

the world's religions, seeks to plumb the heart of our existence. Yet, as Davies tells Science & Spirit's Marianna Krejci-Papa, the science we have today may not be enough to answer our biggest questions. Nonetheless, for reasons that reveal much about our nature, we will continue to ask them.

Science & Spirit: You wrote in your 1983 book God and the New Physics that science is the surest route to understanding God. Do you still believe this?

Paul Davies: When I wrote that, I was being provocative. I wanted to make the point that science has something to say about these deep questions that were formerly just the province of religion. That's not to say that science can provide the answers, but it can often change the conceptual framework in which the questions are asked. Take, as an example, the nature of time. There was a long-standing debate about whether God is inside of time or outside of time, or both simultaneously. This became a nonissue with the rise of modern cosmology and the theory of relativity, where we understand that time is part of the physical universe, like space and matter.

The other point about science is that it deals in claims that can be tested. This makes scientific knowledge more reliable than religious experience that is confined to just one person. If scientists make a statement about the world, then other people can go and check it. I don't deny that a lot of things that are important to people are not testable in the scientific way. When other forms of intellectual activity make claims on a subject that science can also speak to, scientific knowledge is more reliable. It is not infallible, but it is reliable. It is reliable precisely because it's not infallible, because scientists change their minds according to new ideas and new experiments. It's essential that scientific knowledge is regarded as provisional, but that's what makes it all the more reliable: It's the best guess we've got at any given moment, and the guesses get better all the time.

S&S: So you see science as a way of framing existential questions such as the nature of truth and the meaning of life.

PD: The science books that sell well address fundamental issues. People don't care about technicalities like how you measure the mass of a neuron or how you make a transistor, but they do want to know how new discoveries change the way they think about themselves and the world. So the fascination with popular science is part and parcel of this ongoing desire of human beings to see something beyond themselves. That deep need, that yearning, is there, I believe, in almost everybody. It is part of the spiritual side of human beings, and I see the work I do-looking at the Big Questions through the lens of science-as addressing genuine spiritual needs, especially of people who don't feel the questions are being posed the right way in conventional religion.

S&S: If we want to discuss the purpose of humanity within a religious context, we have to choose among traditional religions like Christianity or Buddhism or Judaism, or from newer forms of spirituality. Do you see science as transcending these distinctions?

PD: This is a really important point. I can go to a physics conference and there can be participants from every culture you might like to imagine, and they might be worlds apart in their day-to-day lives or their politics, but as soon as they start talking about physics, everyone's on the same wavelength. Science is for everybody. It is a wonderful, unifying culture within itself.

S&S: You've given a lot of thought to the question of whether we are alone in the universe. Are we any closer to knowing if there is intelligent life beyond Earth?

PD: Whether there is life of any sort on other planets is the biggest unknown, since going from no life to life is the hardest and most mysterious step of all. Once life gets going, it has a chance of developing intelligence, and intelligence has good survival value. So, at least in some fraction of planets that have life, intelligence should emerge. But the first step, from no life to life, is problematic.

S&S: Can scientists calculate the probability that life has started elsewhere?

PD: The honest answer is no, although there is a famous formula called the Drake Equation that collects probabilities, starting with the probability that there are other Earth-like planets. But we don't know how to work out these probabilities because we have a sample of only one: Earth. A chain is only as strong as its weakest link. In a chain of terms like the Drake Equation, if you've got one term that could have a value anywhere from zero to one, it means the whole equation is useless, except to categorize our ignorance. It could be that there's life just on Earth or just within the solar system, or it could be that life is widespread and intelligence is very rare, or it could be that life and intelligence are widespread. With the Drake Equation, we are flying blind.

S&S: Are there no clues in any modern scientific field?

PD: We know that life established itself on Earth fairly soon after it became a habitable planet. Earth is about 4.5 billion years old. For the first 700 million years, it was mercilessly bombarded by asteroids and comets, so the surface was sterilized on a regular basis. And yet, by 3.5 billion years ago, we find evidence for life, so it got going really quickly once that window of opportunity opened up. Some people see that as evidence for life being probable. Another explanation for this rapid rise is that life didn't start on Earth, but came ready-made from somewhere else. Earth and Mars trade rocks on a regular basis, and rocks could contain microbes. These are the answers we would like to get from forthcoming Mars probes. If it turns out that there was or is life on Mars, and we could establish that it began independently of life on Earth, then we would have two samples in one solar system. That would show that life is almost inevitable in Earth-like conditions. And then we would know that the universe would be teeming with life. That's the best hope for an answer.

S&S: Do we need some fundamentally new science to explain how life originates, or do we already have the tools to figure it out?

PD: We need new science. Research on this subject has been dominated over the last 150 years by chemists. There was a belief in the nineteenth century that life was made of a "magic matter," a peculiar substance that you could make like a cake if you had the recipe. People still use the term "organic chemistry" as if it were really different from all other chemistry. But we now know this is a poor analogy for life. Chemistry is the medium, but it's not the message, and you should never confuse the medium with the message. My own analogy is radical. I think of the living cell as a supercomputer. It's an information processing and replicating system. Some people even think the universe is an information processing system and matter is a manifestation of this information.

S&S: So is there any way to determine if we are alone in the universe?

PD: The best way is to go take a look. That's why I'm a strong supporter of SETI. They are searching and listening. I'm on the SETI post-detection committee, so I'll be among the first to know if somebody picks up a signal.

S&S: What's the best that SETI can do?

PD: The system currently under construction, called the "Allen [Telescope]

Array," is going to enable people to search the galaxy with a very high degree of sensitivity. The array is named after Paul Allen, the co-founder of Microsoft. He has donated $35 million for this array. Compared to the amount of money that Americans spend on an election, the $35 million of private money that built this array is nothing. SETI costs so little, it would be a crime not to do it, but I honestly think [the postdetection committee] is one I will not lose any sleep over belonging to because I doubt it's going to meet during my lifetime.

S&S: The Drake Equation is an anatomy of ignorance. You don't expect answers from SETI. So why are you and I, and the rest of our culture, perennially asking if we are alone in the universe?

PD: Frank Drake, the grandfather of SETI, once said that the search for intelligent life elsewhere in the universe is really a search for ourselves. It's a search for who we are and what our place is in the great scheme of things. Whether SETI succeeds or not, it fosters interesting conversations. Like the world's great religions, it asks: What is a human being? What is intelligence? What kind of place is the universe? Different people derive comfort from different answers. Some like to think that we are in splendid isolation, while others-and I'm in this category-like to think we live in a bio-friendly universe in which the emergence of life and mind-consciousness-is built into the scheme of things in a deep way. Interestingly, people who engage in SETI seem to be atheists or even militant atheists. Jill Tarter, director of the Center for SETI Research, has been very outspoken against religion, and yet I see SETI's quest as fundamentally religious.

S&S: Which comes back to modern cosmology as a reworking of age-old philosophical questions.

PD: I think so. The existential questions that for many centuries belonged to religion and philosophy now belong to science, or at least science is trying to adopt them. If you look back at the last 3,000 years of thinking on this subject of extraterrestrial life-there was a lot of speculation done in ancient Greece, and then theologians got in on the act in Europe in the seventeenth century-a lot of words were written, but in terms of knowledge, there was no progress at all. We've learned that science delivers progress. People feel, "Well, once this becomes a scientific project, maybe we'll get some answers." Maybe in twenty or 100 years, we will have more answers, but I think the deepest questions of existence will remain mysterious forevermore.

S&S: You've given me a scientist's answer to the question of whether we are alone. But if you had to guess, what do your instincts tell you?

PD: There is no law of nature, certainly no law of physics, that compels matter to turn itself into life, and no law of biology compels life to turn itself into intelligent life. But if I put my hand on my heart and ask, "What would I like to believe?" It is that we live in a deeply bio-friendly universe, one that is teeming with life in amazing and wonderful forms throughout the galaxy, with other beings like ourselves struggling to make sense of it all. But I have to lay down this enthusiasm all the time because, at the end of the day, one scientific fact is worth a thousand beliefs.

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