by Guillermo Gonzalez and Jay W. Richards
Read any book on the history of scientific discovery, and you'll find magnificent tales of human ingenuity, persistence, and dumb luck. What you probably won't see is any discussion of the conditions necessary for such feats. A discovery requires a person to do the discovering, and a set of circumstances that makes it possible. Without both, nothing gets discovered.
Although scientists don't often discuss it, the degree to which we can "measure" the wider universe from our Earthly home-and not just our immediate surroundings-is surprising. Few have considered what science would have been like in, say, a different planetary environment. Still fewer have realized that pursuing that question systematically leads to unanticipated evidence for intelligent design.
Think of the following features of our Earthly home: the transparency of Earth's atmosphere in the visual region of the spectrum, shifting crustal plates, a large Moon, and our particular location in the Milky Way Galaxy. Without each of these assets, we would have a very hard time learning about the universe. It is not idle speculation to ask how our view of the universe would be impaired if, for example, our home world were perpetually covered by thick clouds. After all, our Solar System contains several examples of such worlds. Just think of Venus, Jupiter, Saturn, and Saturn's moon, Titan. These would be crummy places to do astronomy.
We can make similar comparisons at the galactic level. If we were closer to our galaxy's center or one of its major, and dustier, spiral arms, for instance-the extra dust would impede our view of the distant universe. In fact, we probably would have missed one of the greatest discoveries in the history of astronomy: the faint cosmic microwave background radiation. That discovery was the linchpin in deciding between the two main cosmological theories of the twentieth century. Underlying this debate was one of the most fundamental questions we can ask about the universe: Is it eternal, or did it have a beginning?
The Steady State theory posited an eternal universe, while the Big Bang theory implied a beginning. For a few decades, there was no direct evidence to decide between the two. But Big Bang theory predicted a remnant radiation left over from the earlier, hotter and denser period of cosmic history. Steady State theory made no such prediction. As a result, when scientists discovered the cosmic background radiation in 1965, it was the death knell for Steady State. But that discovery could not have been made just anywhere. Our special vantage point in the Milky Way Galaxy allowed us to choose between these two profoundly different views of origins.
In The Privileged Planet: How Our Place in the Cosmos is Designed for Discovery we discuss these and many comparable examples to show that we inhabit a planet privileged for scientific observation and discovery. But there's more to the story. Not only is the Earth a privileged place for discovery, it is also a privileged place for life. It is the connection between life and discovery that we think suggests purpose and not mere chance.
Physicists and cosmologists began realizing decades ago that the values of the constants of physics-features of the universe that are the same everywhere-must be very close to their actual values for life to be possible. As a result, they began talking about the universe being "fine tuned" for life. And some have even begun to suggest that fine tuning implies a fine tuner. Much more recently, astrobiologists began learning that even in our fine tuned universe, many other "local" things must go just right to get a habitable planetary environment.
If you were a cosmic chef, your recipe for cooking up a habitable planet would have many ingredients. You would need a rocky planet large enough to hold on to a substantial atmosphere and oceans of water and to retain internal heat for billions of years. You would need the right kind of atmosphere. You would need a large moon to stabilize the tilt of planet's rotation on its axis. You would need the planet to have a nearly circular orbit around a main sequence star similar to our sun. You would need to give that planet the right kind of planetary neighbors within its star system. And you would need to put that system far from the center, edges and spiral arms of a galaxy like the Milky Way. You would need to cook it during a narrow window of time in the history of the universe. And so on. This is a partial list, but you get the idea.
This evidence is becoming well known among scientists interested in the question of life in the universe. Researchers involved in the search for extraterrestrial intelligence (SETI), for instance, are especially interested in knowing what life needs. That knowledge would allow them to determine their chances of finding another communicating civilization. Unfortunately for SETI researchers, the probabilities are not looking promising. Recent evidence favors the so-called Rare Earth hypothesis (named after a book written by Donald Brownlee and Peter Ward in 2000). The theory posits that planets hosting simple life may be common, but planets with complex life are very rare.
We do not yet know if we are alone in the universe. The universe is a big place with vast resources. Astrobiology research has not yet matured to the point where we can assign precise probabilities to all the factors needed to make a planet habitable. We cannot yet state with certainty whether they exhaust all the available resources. Perhaps the universe is big enough that at least one habitable planet would have emerged by chance. Or perhaps not. In the meantime, it's difficult to make a strong case for intelligent design based merely on the conclusion that habitable planets are rare.
That said, we do think there is evidence for design in the neighborhood. For, as we argue in The Privileged Planet, there is a suspicious pattern between the needs of life and the needs of science. The same narrow conditions that make a planet habitable for complex life, also make it the best place overall for making a wide range of scientific discoveries. In other words, if we compare our local environment with other, less hospitable environments, we find a striking coincidence: Observers find themselves in the best places overall for observing. For instance, the atmosphere that complex life needs is also an atmosphere that is transparent to the most scientifically useful "light." The geology and planetary system that life needs is also the best, overall, for allowing that life to reconstruct events from the past. And the most habitable region of the galaxy, and the most habitable time in cosmic history, are also the best place and time, overall, for doing astronomy and cosmology. If the universe is merely a blind concatenation of atoms colliding with atoms, and nothing else, you wouldn't expect this pattern. You would expect it, on the other hand, if the universe is designed for discovery.