Evolution and the Anthropic Principle

  In 2000, an event in science shook up our centuries-old perspective of not who we are, but how we are. Two international teams—one organized by the National Institute of Health, called the Human Genome Project, was headed by Francis Collins when it announced that the entire human genome—the biological blueprint for the human being—had been mapped. At the same time, a private organization, Celera Genomics, headed by Craig Venter, announced the same accomplishment.

The meanings of this event will echo in the scientific world for years. Essentially, the genome provides us with detailed information about just how we are alike and how we differ from one another in our inherited characteristics, from eye color to susceptibility to certain diseases.

It also provides us with confirmation (in a big way) of what biologists have known for a long time—the process called evolution, by means of which human beings have developed (along with all life) from single-cell organisms over millions of years. It has also given Craig Venter the tools for what he claims will be the creation of new forms of life.

We’re all familiar with how animals, such as dogs and cats, have been bred to have certain characteristics. There are currently over 400 different breeds of dogs, ranging from the tiny Chihuahua to the huge Great Dane. Every one, however, is of the same species, descended from the wolf. This human-initiated variability has been practiced on many domestic animals, and we are no longer surprised when someone announces a new breed of dog or cat—designer breeds, as they are now called. (Inter-species breeding, however, is rare.)

The point is that the manipulation of genetic information is not new. With the success of the Human Genome Project, we now have more sensitive tools to alter formerly inherited characteristics.

Inheritance was once almost entirely dependent upon chance. Early in human history, however, people began to notice that certain behavior tended to be detrimental to progeny. For example, mating between closely-related people sometimes led to unhealthy offspring. Although the practice became taboo thousands of years ago, we now know precisely why it happens. By the same reasoning, we know that mating between people with certain abnormalities is likely to produce even more pronounced abnormalities in their children. With this knowledge, people can take steps to minimize the chances of handicapped people being born. Deliberate alteration of the human species is taking place. Darwin ’s discovery of natural selection as the engine of evolution makes possible our taking responsibility for what we used to believe was part of the mysteries of life.

Venter’s claim that he is on the verge of creating a new life form is simply another step in our taking charge of our biological destiny. What used to take nature millions of years is now almost within our ability to accomplish in a generation.

Natural selection explains the huge variety of plants and animals that have evolved during the past few million years. Those organisms which have some advantage tend to survive and propagate better than their contemporaries. Most of the variations that enable them to do this are due to the way genes are combined in reproduction. For example, the DNA in each individual has half the genes from its mother and half from its father. How those genes are combined is in part dictated by chance. The probability of two unrelated individuals having exactly the same genome is so slight as to be all but impossible.

The beginning of life on Earth occurred as an event of similar improbability. But, as Richard Dawkins, renowned evolutionary biologist, points out, “all but impossible” is not the same as “impossible.” This highly unlikely event had to happen only once, and we can thank that bit of chance, called the Anthropic Principle, for our existence. All that term means, in our present context, is that no matter how improbable something might be considered, if it exists then that slim chance came up on the roll of the dice. Once it happened, the more ordinary process we know of as natural selection made possible, over millions of years, the fabulous variety of life as we know it. Most of the changes that have resulted in this variety and the extensive complexity of some organisms (including us) are individually small and gradual. The probability of each change is anything but minute, even to the extent of being in some cases almost inevitable. Evolution, then, is not a far-fetched idea.

Dawkins suggests, however, that another one of these changes might have been a once-in-millions-of-years kind of probability, similar to the creation of life itself—human self-consciousness. That would explain, perhaps, why it is so rare among the species that exist. It would be another example of the Anthropic Principle—no matter how unlikely, if it exists, it happened. The probability of its happening again is just as small. We can, once more, thank the universe that it happened once.

Dawkins, by the way, is an atheist. His latest book, The God Delusion, is a polemic on why God does not exist. There are other scientists, however, who have not denied the existence of God even though they live and work in the world of the evolutionary and biological sciences. Francis Collins, for example, one of the foremost pioneers in genomic research, is an avowed Christian, and has published his own book, calling evolution The Language of God.

Whether or not one attributes the existence of the universe to a supernatural being, our growing knowledge of evolution has become a tool for humans to understand not only how we came to be but how we can begin to make our once-wild world more hospitable, more manageable and more humane.

Donald Skiff, January 30, 2008

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