Interview with Professor Nicola Cabibbo
July 18, 2005

By John L. Allen, Jr.
Rome

A July 7 op/ed piece by Cardinal Christoph Schönborn of Vienna in The New York Times on evolution has caused no small amount of ferment in both scientific and theological circles. In it, Schönborn challenges the widely held perception that the Catholic church has reconciled itself to the theory of evolution.

To talk these issues through, NCR Rome correspondent John L. Allen Jr. sat down with Professor Nicola Cabibbo, president for the past 12 years of the Pontifical Academy of Sciences. A 78-member panel of distinguished scientists from around the world, the academy advises the pope on scientific matters. It's descended from the "Academy of the Lynxes," founded in 1603, making it the oldest scientific academy in the world.

The full text of the interview follows.

NCR: What did you think of The New York Times article by Cardinal Christoph Schönborn of Vienna on evolution?
Cabibbo: Two things struck me, one positively and the other negatively. Positively, it opens a very interesting discussion. But I cannot agree with the way he handled the address of John Paul II to the Pontifical Academy of Sciences in 1996. I don't know if the problem was in a bad translation from German, but he calls it "vague and rather unimportant." I've never considered it that way, in fact I have always considered it very important. Not only for the now famous statement, that evolution is "more than a hypothesis," but also for what comes next: "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," the Pope said. With these words the Pope demonstrated a clear understanding of the scientific method, on how an hypothesis can be transformed into a widely accepted fact. This allocution is in fact a very articulated expression of the thought of the late John Paul II.

The theory of evolution can be disturbing to Christians because it seems to clash with the idea of divine creation. This fear is, however, unfounded. What clashes with divine creation is a possible extension of the theory of evolution in a materialistic direction, the so-called "evolutionism." What evolutionism seems to say, and here I'm thinking about authors such as Dawkins, is that there's no need for God. But this extension of Darwin's theory is not part of what has been discovered by science. What has been discovered is a series of facts about biology, about the relationships of different species of living beings, including man, all structurally related to each other. We can live because our proteins are similar to those of plants and animals so that, when we eat, we are able to incorporate biological material from other organisms. This is obviously necessary for human life, since we are not able to do photosynthesis. This overarching system of living beings has a history. The great intuition of Darwin was that there is an evolution, that different species evolved over time, even if he could not at the time understand the mechanisms which made evolution possible.

Darwin's intuition drew on two sorts of influences. One was the study of ancient species that are now extinct. He was interested in fossils, geology, in brief in the role of the passage of eons in shaping the surface of the earth. Secondly, he was an English gentleman and a landowner, and so he was interested in animal husbandry. He knew that you can modify the appearance and function of horses or pigeons, or other animals, by selection. These two sources of inspiration led him to propose the theory of evolution, based on mutation and natural selection. What he did not have at the time was a mechanism for mutation, and this was only clarified by the discovery of DNA, and of its role in genetics. We have a fair idea now of how evolution works, though most of it should be considered as on-going research.

This is all part of what the pope wanted to say, comparing notes as it were with what Pius XII had said 50 years ago, before the discovery of DNA. At that time, we were still essentially at the point where Darwin was, there had been no great breakthroughs. Since then molecular biology gave us the theory of evolution as we know it now.

To this, there are two different reactions. One is the atheist view, according to which, now that we now know how life works, we don't need God any more. This is a metaphysical conclusion that goes beyond the scientific facts. The other is the theistic response, believing that God is the cause of this process. This is an interesting part of the discussion Cardinal Schönborn's article has raised, because actually the contrast between evolutionism and creationism has nothing to do with science. They are instead two very different religious and philosophical positions. The controversy is not scientific, but philosophical.

What troubles many people, including Schönborn, is that scientists use words such as "unguided" and "unplanned" in referring to evolution, which seems to exclude God. As a scientist, what do those terms mean to you?
Let me take this from a distance. In Italian, there is a popular saying, non cade foglia che Dio non voglia. [No leaf falls unless God wants it.] What science tries to do is to try to explain how the leaf falls. For example, gravity. Gravity explains at the scientific level how the leaf falls. I once was told that St. Thomas put it this way -- everything descends from the will of God, but this doesn't mean that what happens doesn't have its own logic, its own way of happening. We are not puppets in God's hands, without the means --- volition, muscles --- to do whatever we do. It would be debasing to think that God is directly causing every leaf to fall from the tree. Instead there is a system, a mechanism, by which things do happen. I think there is no philosophical, no theological, problem here. This was the thought of John Paul II -- there is no a priori reason to see a clash between science and religion. They're doing different things.

As for evolution, its basis is mutation. For evolution to occur, you need progeny that is not identical to its parents. We know fairly accurately how this works, and there is an element of chance in it. This discovery was due not only to a great Catholic, but a great priest, Gregor Mendel. He discovered that genetics operates according to principles of probability. You cannot cross a yellow and a green pea, and automatically get a certain result. Mendelian laws are statistical laws. We now know that in sexual reproduction, the new DNA of the descendant is a somewhat random mixture of that of the parents. We also know that there can be errors in the transcription of the new DNA from the old, and this is how, through a process which has elements of chance, progeny is not identical to its parents. The presence of a random element in reproduction may be disturbing, especially because it is a source of diseases, but it seems to an inescapable conclusion of the knowledge accumulated during the last fifty years . But for religious belief the existence of random elements in reproduction should not be of greater concern then the discovery that the Earth turns on itself and around the Sun. There seems no doubt that evolution is a salient element of man's history. We know that, before humans similar to the present inhabitants of the earth, there were populations significantly different from us, with different cranial features and so on. But these people painted their caves, built elaborate instruments, mastered fire, they were human.

Is it fair to call this process "unguided"?
Here we enter a very difficult theological problem, which is how the action of God is operates in nature. Books have been written on this subject. Fr. George Coyne, a respected astrophysicist, the head of the Vatican observatory, has organized conferences on this very topic. These are interesting studies, but removed from what we consider science. There are many mysteries in nature. We know that revelation told us that God came and manifested himself to us. But scientifically, "unguided" means that as an empirical matter, we don't see guidance in nature. We see the very clever mechanism by which evolutionary change occurs, through these random mutations. Scientists believe these changes to be based on a combination of mutation and selection, which in general favors positive adaptations. Some changes, of course, do not. There may be aspects of evolution that do not respond to selection. I don't know, for example, whether the fact that young people today are taller than we were 50 years ago has any evolutionary meaning. It could even be irrelevant. But there is no scientifically verifiable mechanism for the guidance of evolution except for the combination of mutation and selection. On the subject of selection, we are essentially in Darwin's situation. We know that farmers can select, and we suspect that nature selects. It selects in ways that tend to favor survival and reproduction, ensuring that organisms are well suited to their ecological niche. There is no scientific way of measuring the presence of God. The admiration one feels for the beauty and magnificence of creation can be increased by what we discover, of course, but that's not a scientific reaction. Some of these terms, like "unguided," are a little bit tainted by a materialistic point of view.

Rather than calling evolution "unguided," I would say that it's guided by itself, in a way. The evolution of a single species is guided by the environment, by changes in the environment. For example, a new predator appears on the scene, and an insect species is guided to develop a different color. This is the general idea. The environment is the visible hand of evolution.

The International Theological Commission in 2004, in its document Communion and Stewardship, wrote that God's causation is of a radically different sort than natural causation, and that God can work both through necessity and through contingency. Thus the fact that evolution involves a random element does not mean that God is not the cause of it. Would you agree?
That's the whole point. This is why John Paul II was not afraid of evolution. How can you be afraid of something that is true? Of course, in understanding the mechanics of evolution we are not at the level of precision and certainty achieved in many aspects of the physical sciences. There's still a lot to be discovered to fill in the gaps in our understanding of life at the scientific level.

When Cardinal Schönborn says that purpose and design can be clearly discerned in the natural world, would you agree?
Not scientifically. As a scientist, I cannot draw this conclusion. What I can say is this: If the will of God was to create man, he certainly organized things in a beautiful way to do it. Of course, we know by revelation that God wanted to create man, but we don't know how he did it. This is what science attempts to explain. There cannot be any clash or controversy between science and religion, because they work on different planes.

Does the scientific understanding of how life was created and how it evolved, in and of itself, demand belief in a creator God?
I would say no. Scientifically, we don't know. We know the universe is highly complex, and we have no reason to believe there is only one universe, the one we can see around us. Theoretically this could happen in two different ways: some interpretations of quantum mechanics suggest the idea of parallel universes, with histories different from our own. Cosmologists speculate on a multiplicity of "Big Bangs", giving rise to a multiplicity of universes. These are fascinating ideas and we find ourselves in a situation similar to that of Giordano Bruno when he proposed that stars are really suns, that there may be other planets and other solar systems, that the universe is much larger than previously thought. This was part of what got him into trouble! We really don't know. Science is incapable of supplying answers to ultimate questions about why things exist and what their purpose is.

So on the basis of the available information, you can't draw a scientific conclusion in favor of intelligent design?
No. You can say that if there is a design, it is very successful. Science can invoke wonderment. The philosopher Kant said the two things that impressed him the most were the moral law within us and the starry firmament above us.

Some creationists argue that on the basis of an examination of the scientific facts, you can conclude that there must be a creator.
This is not believed by any serious scientist. You can certainly construct an argument about how beautiful the creation is, how clever it is, but these are aesthetic, not scientific concepts.

Do you think the Pontifical Academy of Sciences will want to talk about this?
Yes. In 1996, and this was the occasion for John Paul II's talk on evolution, we studied the origin of life and early evolution, meaning from molecules to bacteria. We looked at molecular evolution, the very early evolution, almost "pre-life," a field that is partly accessible to laboratory experiments. There is a huge gap from the molecular-evolution stage to single-cell organisms. It's not known how it happened. Once you are in bacteria, the knowledge is more detailed. There was a lot of interest at that time in bacteria that were able to live in various conditions, very differentiated environments. I would like the Academy to come back to evolution as a whole, to put together essentially everything that is known at the scientific level. According to the statutes of the Academy we will also explore the epistemological dimensions of the new discoveries.

Will you treat evolution this year?
Probably not this year. Academy meetings require an accurate preparation.

Do you think attitudes in the church towards evolution are moving in the direction suggested by Cardinal Schönborn?
Many academics, especially Americans, have reacted to his article. I don't know if Cardinal Schönborn fully understood how "hot" the situation is in America on this subject. I know many people within the Catholic Church whose attitudes would be closer to mine than those suggested in the article. I think many Catholics, especially Catholic scientists, would prefer to adhere to the 1996 statement of John Paul II.

Do you have any indication what the mind of Pope Benedict might be on this question?
No, but Pope Benedict certainly has an appreciation of science. I'd like to recall that Pope Benedict opened up the archives of the Holy Office, a highly appreciated step for the freedom of scientific research. I remember that he announced it at the Italian Accademia dei Lincei (literally, "the Academy of the Lynxes"), a setting that was not specifically Catholic. The Pontifical Academy and the Italian Accademia dei Lincei both descend from the original Accademia dei Lincei, founded in 1603, the oldest scientific Academy in the world. As Cardinal Ratzinger, Pope Benedict became a member of our Academy together with Cardinal Carlo Maria Martini. Since that nomination, three years ago, he has taken part in the meetings of our academy, and celebrated a memorable mass for the Academy at the Benedictine convent in Cassino. After Pius XII, Pope Benedict is the second member of the Academy to ascend to the papacy.

National Catholic Reporter, July 21, 2005