Astrobiologist Guillermo Gonzalez, who holds a Ph.D. in astronomy, is the co-founder of the “Galactic Habitable Zone” concept, which was featured on the October 2001 cover of Scientific American. His work has helped lead to the discovery of two planets. He is also the co-author of the 2004 book The Privileged Planet, which explains unique insights about life on our planet. Dr. Gonzalez has concluded, based on the scientific evidence, that life is designed. In our interview, Dr. Gonzalez explains his views, gives us a taste of the theories explained in his book, and highlights the opposition scientists face when proposing the idea of intelligent design.

Can you briefly explain the central idea of your book, The Privileged Planet?

The central thesis of the book is that recent scientific findings show that we not only live in a universe fine-tuned for life, but one fine-tuned for discovery as well. Those places in the universe that are most habitable are also the best places to observe the broader universe, and Earth is the best overall “scientific platform” we know of.

What do you think are one or two of the most profound or salient features of our planet that both allow life to exist and allow us to measure and understand our world and universe?

An obvious one is the fact that we can see the distant stars and galaxies. This would not be possible if we lived on a planet with a cloudy or hazy atmosphere. Our atmosphere is transparent in the optical region of the spectrum, partly because it is oxygen-rich. And a thick, oxygen-rich atmosphere is necessary for large, active creatures such as us.Another one is the phenomenon of total solar eclipses. Anyone who has watched a sunrise or sunset and the full moon rising or setting has noticed that these two bodies subtend about the same angular size on the sky. This “coincidence” gives us the best solar eclipses in the solar system. What’s more, the conditions that result in these wonderful eclipses are also the ones that make Earth a habitable planet. In other words, the best places for observing solar eclipses are also the ones most likely to have observers.

You explain how even some characteristics of Earth that we normally think of as hostile—like earthquakes, for example—actually benefit Earth’s habitability and discovery. Why is that?

Earthquakes, while they cause damage and death, are an indicator that we live on a geologically active planet. We need the geological activity so that certain life-essential elements, such as carbon, can be recycled through the biosphere. We could avoid most of the suffering caused by earthquakes if we really wanted to, since we know where most earthquakes occur, but we cannot predict when they occur. We learn about the Earth’s deep interior from earthquakes by making use of the waves they generate.Earth resides in what you call the “Galactic Habitable Zone.” Can you briefly explain what that is, and what problems we would face if we were not in that zone?The Galactic Habitable Zone (ghz) is that region in the Milky Way galaxy that is most favorable to the presence of habitable planetary systems. Its boundaries are defined by such things as the trend of stellar chemical composition with location, perturbations of Oort cloud comets, supernovas and gamma ray bursts. Overall, habitable planets are less likely to form in the outer region of the galaxy, and there are more dangers in the inner regions compared to our location.

What are the odds of all the “coincidences” you explain working out to support both life and discovery, and are there enough planets in the universe to make it possible for those odds to arise by chance?

The science of astrobiology is helping us to begin to answer the first part of your question (probability of a habitable planet), but very little work has been done on the second part. Given the multiple examples of fine-tuning required for discovery I give in my book, I can say it is a low probability to find ourselves living in the universe we do live in, but I’m just not ready to attach a specific probability to it yet.

Critics would counter that despite the odds, it is possible that the conditions arose by chance, if we are just one universe of many. Do you think this is a fair criticism? Is there evidence for the existence of multiple universes?

Yes and no. You can’t rule out the possible existence of other universes, but I would say this hypothesis is not the best explanation for the universe we observe ourselves to be living in. Not only are we living in an improbable universe when it comes to habitability, it is also the case that we are living in an improbable universe for discovery. What’s more, since we don’t need to discover the universe outside our planetary home in order to exist and survive, you can’t appeal to unseen multiple universes to explain the fine-tuning for discoverability.

Some might argue that natural selection is responsible for us appearing to be perfectly suited for our environment. But can natural selection account for our ability for discovery? Can it explain why the factors for life correlate with the factors for discovery? Why or why not?

Good question. Natural selection can only select for those aspects which help us to survive and produce more offspring. It cannot explain why we can see the distant stars and galaxies or observe total solar eclipses. Natural selection might account for sight, but not for our ability to do astronomy. It cannot explain the correlation between life and discovery.

Assuming our planet was designed for complex life, as you suggest, why do you think it was designed in such a way that would allow us to be able to observe and measure the cosmos? Or is that a philosophical question?

Answering this “why” question is philosophical. So, I can give a speculative philosophical answer. Perhaps we were meant to discover those aspects of our universe that point beyond itself to its designer. For example, you can learn some things about a carpenter by studying his furniture or a painter from his paintings or a musician from his music.

Have the many factors making complex life possible been understood for a long time? Or are many of them recent discoveries?

A few have been proposed over a century ago, such as a planet’s distance from its star. Most have been recognized for less than 20 years. For example, the importance of a large moon for stabilizing the rotational axis of a terrestrial planet was discovered in the early 1990s. More recently, gamma ray bursts have been demonstrated to be very dangerous explosions that can sterilize a planet even thousands of light years away.

Despite the fact that you have published over 70 articles, you have been sharply criticized for your research into intelligent design. Why do you think some are so hostile to the idea of intelligent design? Is it fundamentally anti-scientific?

Some people have bought into the mischaracterizations of intelligent design which are so commonplace on the Internet, the pop culture and even in science journals. There is no question that people who spread this misinformation feel threatened; it would be easy for them to look up the correct information [on] intelligent design. Instead, they would rather believe in any number of conspiracy theories about intelligent design, rather than face its profound implications.

What led you to believe that intelligent design is a good explanation for the origin of life?

Although I don’t study the origin of life, I was convinced of life’s design from several lines of evidence: the fine-tuning of the physical constants and planetary [factors necessary] for life and discovery, the information in dna, nanomachines in cells.

Based on your experience, it seems that some in the scientific establishment use their power to blacklist scientists who have not ruled out intelligent design. What do you find unscientific about the way these scholars interact with other scholars?

It has certainly been a learning experience. I have been surprised at the extent to which scientists’ views are determined by political ideology. This is not only true of the opposition to intelligent design, but it also applies to other scientific controversies, such as global warming and embryonic stem-cell research.

Some of your research is in astrobiology. What is astrobiology? Astrobiology seems almost a contradiction in terms. When we look out at the stars, it seems that we see nothing but a lack of life, no? Do you think there is life out there somewhere?

Astrobiology is the study of life in the universe. The discipline used to be called exobiology, which is the study of life beyond Earth. But, that meant that it was a discipline without a subject. With astrobiology, Earth life is an instance of life in the universe, but it remains true that Earth is the only inhabited place we know of. Based on what we know today, I am doubtful that life could have arisen naturalistically in the universe. Whether the universe was designed to have more than one planet with life is a question I don’t have an answer for.

Of the various things you study, what do you enjoy studying the most? Why?

I most enjoy studying stars with planets. This is a new field with many new discoveries waiting to be made. I feel privileged to be involved in this field from the start and making a number of important discoveries.

Guillermo Gonzalez’s book, The Privileged Planet, explains in detail many factors that not only make Earth habitable, but also make our world and universe discoverable at the same time. It’s an excellent read for anyone interested in learning more about our planet and our universe. It’s available at Amazon.com and elsewhere. In addition, a DVD is available by the same title, based on the book.