In March 2009, the Vatican Pontifical Academy of Sciences and the University of Notre Dame sponsored a conference entitled “Biological Evolution: Facts and Theories” as part of a year-long celebration of the 200th anniversary of the birth of Charles Darwin and the 150th anniversary of the publication of his revolutionary book, The Origin of the Species by Means of Natural Selection.
The relatively simple scientific theory of evolution met with resistance, not only when it appeared in 1859, but also today. In this Catholic Update, we will explore the reasons for this resistance and why the theory of evolution is not inconsistent with Catholic teaching.
The importance of Darwin’s ideas is highlighted in Darwin’s Vision and Christian Perspectives, edited by Walter Ong, S.J. He writes: “There can be no doubt that the discovery of the process of evolution, cosmic and organic, has been one of the greatest achievements of the human mind. In a sense, this is the central discovery in the Western world since Renaissance times, and in a still further sense it is the central corporate discovery of all mankind.”
Two major reasons for resistance to evolution are: 1) the mistaken idea that Darwin’s theory of evolution excludes supernatural involvement in the development of the natural world, and 2) the general public’s limited understanding of the scientific evidence that has made this theory universally accepted in the scientific community.
The idea that the great diversity of living creatures had developed over long stretches of time had been around for many decades before Darwin. His ideas were well-developed when he wrote Origin in 1838. He delayed publication because he knew how religious people might react to the revolutionary notion that nature’s huge variety of living beings came about by natural processes over millions of years—rather than through direct creation by God in six days, or 6,000 years. Although when Darwin published Origin he was probably agnostic, he wrote, “By ‘nature,’ I mean the laws ordained by God to govern the Universe.”
Evolution need not threaten faith
How do we today understand the term “laws of nature”? How many persons see the constant miracles in the natural world as awesome signs of divine activity? How many Catholics realize that Pope Pius XII’s 1950 encyclical, Humani generis, indicates that duscussion of biological evolution is compatible with Christian faith (#36)—as long as God’s intervention is recognized as necessary for creating the human soul.
Pope John Paul II stated in 1996: “[N]ew scientific knowledge has led us to realize that the theory of evolution is no longer a mere hypothesis. It is indeed remarkable that this theory has been progressively accepted by researchers, following a series of discoveries in various fields of knowledge. The convergence, neither sought nor fabricated, of the results of work that was conducted independently is in itself a significant argument in favor of this theory” (Message to the Pontifical Academy of Sciences on Evolution, October 23, 1996).
Can we not then accept the idea that the Eternal Creator chose an evolutionary way of creating the natural world—and that creation is still occurring?
In his recent book, Darwin’s Gift to Science and Religion, Francisco Ayala, one of the leading evolutionary biologists of our time, who has a strong background in Catholic theology, explains, “If properly understood, science and religious beliefs need not be in contradiction because science and religion concern different matters.”
They are two of the many ways of human knowing—art, music, philosophy, history and common sense, to name a few others. I believe it is not coincidental that the order of appearance of the sun, water and living beings on Earth is almost identical in the scientific story and in Genesis.
Unfortunately in our culture today, many people do not understand how scientific investigation works and what science tells us about our world.
Modern science began in the 16th century, observing the processes that occur in the natural world. The scientific method involves developing hypotheses and then testing them to see if what is actually observed supports a hypothesis. Religion concerns meaning and purpose in the world and the relations of persons to each other and to God. So religion and science have different goals and methods.
Using the scientific approach, Darwin’s painstaking observations in various populations of plants and animals over many years qualified him to offer a revolutionary theory of natural selection. Its major points include: 1) Populations of plants and animals grow and face limited resources; 2) In the resulting struggle for existence, individuals with traits that help them overcome adverse environmental factors are more likely to survive and reproduce; 3) Their offspring tend to inherit the characteristics of the parents; 4) Individuals with non-advantageous traits eventually disappear from the population; and 5) Over the course of many generations, this process of natural selection gradually transforms the species.
Points one through four above seem fairly obvious to any observer. The last point actually describes “descent with modification from a common ancestor,” as Darwin described the process and the resulting variety of species. Darwin did not use the term “evolution of species.”
Darwin’s own evolving career
Skeletons tell the story
Darwin’s curious nature and tireless observation supported his conclusions. After two years as a medical student, Charles left the University of Edinburgh for Cambridge to prepare to become an Anglican cleric. Because many of the naturalists then were country pastors, his physician-father approved—even though he preferred that Charles become a doctor.
Even as a boy, Charles was deeply interested in natural history, and shortly after his graduation from Cambridge he embarked on a five-year trip as the naturalist on the H.M.S. Beagle. His father agreed reluctantly, afraid that Charles would never amount to much.
Many of his most important observations were made in extended trips ashore where he collected countless specimens. The discovery of fossil bones of large extinct mammals in Argentina and observations about the distribution of animals on the Galapagos Islands (about 600 miles off the coast of Ecuador) greatly stimulated his interest in how species originate.
Here there were many giant tortoises—galapagos is Spanish for “tortoises”—different ones on different islands, and all of them different from those found elsewhere in the world. These large populations could not have existed had there been predators, but here there weren’t any.
How many different fields can provide evidence for evolution? In Darwin’s time the major ones were the fossil record, comparative anatomy, comparative embryology and bio-geography. Each of these contributed enormous amounts of information to support the idea that living organisms have varied greatly both in time and in location.
Nearly everyone realizes that dinosaurs once dominated the planet, starting about 230 million years ago. Scientists think that dinosaurs became extinct about 65 million years ago when a large asteroid collided with Earth near the Yucatan peninsula. Though catastrophic for dinosaurs, their disappearance may, in fact, have been the only way that mammals could have started flourishing.
Strong evidence of similarity emerges from studying the skeletons of vertebrate animals. For example, the forelimbs of the whale, bird, dog and human—though used for different functions—contain one large bone above and two paired bones below the “elbow” joint.
Another example: Unless experts know their origin, some may find it nearly impossible to distinguish among very early embryos of fish, salamanders, tortoises, chickens, pigs, cows, rabbits and even humans.
Evolution helps explain why some animals and plants are found only in certain parts of the world. For example, North America and Europe, on both sides of the North Atlantic, have many similar animals; geologists have found that at one time a wide land bridge connected these two continents. Yet there is little similarity of animals in Africa and South America, which are widely separated by the South Atlantic. Hawaii has more than 1,000 unique species of snails, thanks to the extreme isolation of these islands.
For these and other reasons, the theory of evolution is more than a theory. We now have much more evidence than Darwin did. In the mid-19th century, the mechanism of heredity—how the changes that he was observing came about—had not been discovered.
In 1865 in Brunn, Austria, a paper by Gregor Mendel, an Augustinian monk in the Austro-Hungarian Empire, was presented, describing how genes operate. His work did not become known until it was rediscovered by three scientists around 1900.
Had Darwin known of Mendel’s work on genetics, the scientific community’s reluctance to accept Darwin’s theory of natural selection might have been much less. The mechanism of heredity clearly shows how the changes he described were passed from generation to generation. DNA has become a household term after the discovery of this amazing molecule’s structure, which carries the unique genetic coding for each organism.
All living cells—whether single-celled organisms like bacteria and fungi or large, multicellular organisms—are very similar. Their chemical composition and their function reveal the genetic continuity and common ancestry of all living organisms.
Today’s ongoing studies in molecular biology provide the strongest evidence for evolution. They show how all living beings could have evolved from simple, single-cell organisms. We can show in a lab what Darwin meant when he affirmed, “All the organic beings which have ever lived on this earth descended from some primordial form into which life was first breathed.”
Appreciating this evolutionary mode of creating the awesome diversity of the world’s living beings can give us a new image of our Eternal Creator—one which we can find very exciting! The mystic Meister Eckhart was way ahead of his time when he stated some time before 1327, “Every single creature is full of God and is a book about God.”
Perhaps the area which has caused the most controversy is the idea that the human species, homo sapiens, is the most recent addition to the evolutionary tree of life. Evidence for the descent of humans from the primate line, however, is enormous.
The most recent evolutionary branching has resulted in the chimpanzee and hominid lines; homo sapiens has developed from the latter. Although no fossils of the common ancestor have yet been discovered, molecular biology shows that human macromolecules closely resemble those of chimpanzees. For example, many enzymes and other proteins, such as hemoglobin, are virtually identical.
Francis Collins, head of the Human Genome Project, has mapped all the genes on human and chimpanzee chromosomes. He writes, “Humans and chimps are 96-percent identical at the DNA level.” He continues: “It is time to call a truce in the escalating war between science and spirit....Science is not threatened by God; it is enhanced. God is certainly not threatened by science; He made it all possible.”
Teilhard and Benedict
Many scientists since Darwin’s time have realized that scientific searching can result in the awesome realization that creation is an ongoing process, set in motion by an Eternal Creator.
In 1881, only 10 years after Darwin published The Descent of Man, Pierre Teilhard de Chardin was born in France. After extensive study of hominid fossils and early human societies, this Jesuit paleontologist in 1938 completed his most important work, The Phenomenon of Man. His religious superiors found his thinking unorthodox and forbade him to publish.
After Teilhard’s death in 1955, many of his works began to be translated and published. He originated the concept that humans are a phenomenon of Earth’s evolutionary adventure, which is moving toward the Omega Point, the Cosmic Christ. The influence of Teilhard’s ideas has been far-reaching because very early he integrated broad scientific knowledge with a deep sensitivity to religious values.
At vespers on July 24, 2009, Pope Benedict XVI endorsed Teilhard’s thinking. In a homily about the priesthood, rooted in God’s power and goodness, he said: “The role of the priesthood is to consecrate the world so that it may become a living host, a liturgy: so that the liturgy may not be something alongside the reality of the world, but that the world itself shall become a living host, a liturgy. This is also the great vision of Teilhard de Chardin: In the end we shall achieve a true cosmic liturgy, where the cosmos becomes a living host.”
Influenced by Teilhard’s work, the late Thomas Berry, a Passionist priest who called himself a “geologian,” recently has provided our 21st-century world with timely wisdom. He agrees with Teilhard’s idea that “we must consciously will the further stages of the evolutionary process.”
As a cultural historian, he was eminently qualified to state: “Natural selection can no longer function as it has in the past. Cultural selection is now a decisive force in determining the future of the biosystems of the Earth.”
To a large extent, the further development of the human family in what Berry described as the “sacred Earth community”—the entire created universe—is in our hands.
Father Berry explained in 1999, “The Great Work now, as we move into a new millennium, is to carry out the transition from a period of human devastation to a period when humans would be present to the planet in a mutually beneficent manner.
“We cannot doubt that we too have been given the intellectual vision, the spiritual insight and even the physical resources we need for carrying out this transition.”
Our times require that all of us appreciate our part in this great work of co-creation.