Stephen M. Barr is a professor of physics and astronomy at the University of Delaware, where he serves as a member of the Bartol Research Institute. He holds a PhD in physics from Princeton University. In his research, he specializes in theoretical particle physics and cosmology. He was elected as a Fellow of the American Physical Society in 2011.

A frequent lecturer on the topic of faith and religion, Professor Barr was awarded the Benemerenti Medal by Pope Benedict XVI in 2007 and was elected a member of the Academy of Catholic Theology in 2010. He is the author of “Modern Physics and Ancient Faith” (2003) and a frequent contributor to First Things magazine.


On Nov. 9, I interviewed Professor Barr by email about the intersection of faith and science.

What current projects are you working on?

As far as physics research goes, I am working on an idea about the nature and origin of “dark matter.” I am also working on some ideas related to so-called "grand unified theories" (one of my areas of expertise) and about the way different types of neutrinos "mix" with each other.

As far as writing about science and religion goes, I am working on a book that explains how to think about Evolution from a Catholic point of view.

You’ve argued that modern physics is more compatible with Judeo-Christian teachings about God, the cosmos, and the human soul than with the atheistic viewpoint of scientific materialism. What allows you to make this claim?

This is the thesis of my book “Modern Physics and Ancient Faith.”

As of about 100 years ago, many people saw the developments or trends in science up to that time as supporting atheism and materialism. However, certain discoveries since then, especially in physics, can be seen as pointing the other way, towards a metaphysical picture more in line with Christianity and Judaism. I discussed five of these in some depth in my book. Here I can do no more than list them:

First, science once seemed to support the idea that the universe was “past eternal,” i.e., had no temporal beginning, and the idea of a Beginning came to be seen as religious mythology. Now, however, there are very strong arguments that the universe and time itself had a beginning, either at the Big Bang or possibly earlier.

Second, physics has found that the universe is governed by mathematical laws that have an intricate and subtle structure based on deep mathematical ideas. That matter itself is based on ideas suggests that the material world is the product of a mind. This is what Pope Benedict XVI referred to in his Regensburg address as the “platonic element in the modern understanding of nature.”

Third, the laws of physics have many features that are just right to make the existence of organic life possible—these are sometimes called “anthropic coincidences.” This belies the common atheist claim that everything science has discovered about the universe makes it seem “pointless.” Indeed, even the unimaginably vast size of the universe, which is often thought to show our insignificance in the cosmic scheme, is actually required for the universe to last long enough for life to evolve (at least if gravity behaves as Einstein said it does).

Fourth, one of the strongest challenges to traditional religion was the seeming fact that the laws of physics were “deterministic,” leaving no room for human free will. But quantum mechanics overthrew physical determinism in the 1920s.

And fifth, there are strong anti-materialist arguments based on the logical structure of quantum mechanics and the role that “observers” play in it. These arguments go back to the great mathematicians and physicists von Neumann, Wigner, Peierls and others.

How do you reconcile faith and science in your life?

The word “reconcile” is wrong here. It suggests that there is a conflict that has to be resolved. I have never felt there to be such a conflict; rather, science and the Catholic faith have always seemed to me profoundly in harmony. Both involve a conviction that the world makes sense and that everything fits together in some coherent way. Physics gives us a wonderfully coherent picture of the physical world, the world of sensible and measurable things. The Catholic faith gives us a wonderfully coherent view of reality as a whole. Science is based on faith in the power of human reason to understand the world. The Catholic faith tells us that the world is the product of eternal Reason, the Logos of God.

Who is God to you?

Existentially speaking, He is my Creator and savior.

If you mean how do I conceive of God, I would say that Scripture and Tradition give us many images and ways to think about Him, and it wouldn't be good to limit ourselves to just one. But one that has especial force for me is God as Light—“light from light,” the light that shines in the darkness but is not comprehended by it. Not a physical light, but intellectual light. The great Jesuit philosopher, Bernard Lonergan, whose book Insight greatly influenced me as a teenager and since, wrote of God as “the Unrestricted Act of Understanding” that grasps all of reality. (Of course, St. Thomas said the same thing.) I like to think of God as a blinding flash of understanding that comprehends all things, including Himself. The first Letter to Timothy says that God “dwells in unapproachable light.”

Does God act only within the laws of nature?

Certainly not. He gave to nature its laws, but is not bound by them. The one who gives the law can suspend the law. We know that God has in many instances acted in a way that contravened the laws of nature. Such miracles seem always to be done either to show God's favor to His people or to show that someone is acting or teaching in His name.

In other words, miracles have a salvific purpose. Of course, God also acts in many ways in the world that are beyond but do not contravene nature and its laws. For example, the Incarnation, the indwelling of the Holy Spirit in the souls of the faithful, the working of grace, the inspiration of Scripture, mystical experiences and much else.

As a man of science and a man of faith, how do you understand miracles?

Many scientists would have a hard time accepting the possibility of miracles. Having seen the wonderful perfection of the laws of physics, a violation of those laws almost seems like a rent in that finely wrought fabric. But I think that if there were no miracles human beings might be tempted to conclude that nothing was superior to the power of nature, and that we were therefore doomed to be crushed beneath that power. Miracles show both God’s love for us and His power over nature, and therefore give us hope.

Does science disprove the Bible?

It could only do so if the Bible is construed as making assertions about the nature of things in the physical universe. But, as Pope Leo XIII taught in "Providentissimus Deus," that is not the right way to read the Bible. St. Augustine famously warned in vehement terms against interpreting Scripture in a way that would make it seem to conflict with what is known "by experience and the natural light of reason."

How does your Catholic faith inform the way you do science?

There is not a specifically Catholic way of doing science. But to one who sees with the eyes of faith, science reveals something of God's glory.

How does the way you do science inform your Catholic faith?

Primarily by increasing my awe of God. What modern physics has revealed of the hidden depths of nature and of its vastness both in space and time makes one appreciate that God is, as the Dies Irae calls Him, a "Rex tremendae maiestatis," a King of tremendous majesty.

What do you say to people who believe there’s no way to prove God’s existence?

The word "proof" suggests the kind of deductive demonstrations that one has in mathematics. But that is not the way we come to know most things, whether in everyday life, in natural science, in philosophy, or in religion. We come to believe that a scientific hypothesis is true not by a syllogism or a logical demonstration but because it is supported by many converging lines of evidence, and because it makes many pieces fall into place. In a somewhat analogous way, one can come to a rationally justified belief in God by the "natural light of reason." Of course, that falls short of the certitude of faith, which is a gift of the Holy Spirit.

What’s the greatest congruence between your Catholic faith and what you have learned through science?

Here I would quote a great mathematician and physicist of the 20th century named Hermann Weyl. He said, “Many people think that modern science is far removed from God. I find, on the contrary, that…in our knowledge of physical nature we have penetrated so far that we can obtain a vision of the flawless harmony that is conformity with sublime reason.”

What’s the greatest tension between your Catholic faith and what you have learned through science?

I have never seen any area of tension between physics and the doctrines of the faith. There may be some tension with certain speculative theological opinions. For example, I have encountered the view that our resurrected bodies will just be somewhat improved versions of our earthly bodies, with all the same organs, tissues, molecules, and so on, and that the next world will just be this universe a bit transformed and renewed. If that were so, then the next world and our glorified bodies would still be “in bondage to decay,” because any complex physical system must be. For that reason, I believe one has to be careful not to interpret Romans 8:21 in too naive a fashion, as I think some do. St. Paul himself was not at all naive on these matters and well understood that physical systems are inherently subject to corruption and decay, as is shown by what he said in 1 Corinthians 15:35-44 and 50-54. Again, it is not Catholic doctrine, but certain naive theologies may from time to time create difficulties.

Do the Big Bang theory and evolutionary theory contradict Christianity?

No. Some Christians seem to think that the Big Bang theory is contrary to biblical teaching. Mostly, these are fundamentalist Protestants, but a few Catholics think this too, which I find ironic and amusing. The originator of the Big Bang theory was Georges Lemaître, who was a Catholic priest as well as a brilliant theoretical physicist. One reason that the Big Bang theory was slow to gain acceptance (though not the primary reason) was that some physicists thought it smacked of religion! Pope Pius XII was extremely enthusiastic about it, as he saw in it (quite reasonably) a vindication of the doctrine that the universe had a Beginning, which he said pointed to its contingency. He gave a famous address to the Pontifical Academy of Sciences in 1951 arguing this very point. This alarmed Fr. Lemaître, who worried that the pope was getting too far out in front of the science, because the Big Bang theory in 1951 was still very controversial and fraught with technical problems—which were later resolved. The Big Bang theory is now regarded as solidly confirmed.

Evolution also is not a problem for Catholic theology. But I will leave that to my next book.

What’s your favorite Bible verse and why?

It is hard to pick just one, rather than hundreds. I have mentioned a few already—from the gospel of John and from First Timothy. Another of my favorites is Isaiah 55:9, "As far as the heavens are above the earth, are my ways above your ways and my thoughts above your thoughts."

What do you hope people will take away from your work?

I hope they come away with the realization that the church has never been an enemy of science, but rather a great patron and friend of science, and that scientific discoveries do not undermine the teachings of the Catholic faith, but if looked at aright give them even greater credibility.

Sean Salai, S.J., is a contributing writer at America.