Any reference to “Catholic scientists” might appear to mean scientists who happen to be Catholics, just as one would speak of politicians, economists, or writers who happen to be Catholics. The phrase “happen to be” suggests a merely accidental pairing, as though each half of the phrase “Catholic scientists” is true but there is no whole — no real unity or single identity. A culture in which religious belief is generally relegated to the sphere of private practice encourages such a view. So we are told that we ought not to mix religion with essentially secular activity — like science.
But we are not very consistent in this view. We often hear arguments about the need to take action about global warming, or to support various new medical techniques, or to encourage or prevent human reproduction. In these and many other cases, it is obvious that we cannot exclude ethical questions from scientific and technological practices. And since ethics involves both reason and faith, we implicitly grant an important role to religious belief in certain scientific activity. We tend, however, only to legitimize those religious arguments concerning such activity when they support what we already have decided needs to be done — for example, reduce our carbon footprint or encourage embryonic stem cell research.
What would it mean to be a Catholic scientist — as distinct from a scientist who happens to be Catholic? This is a question central to the new Society of Catholic Scientists, which had its inaugural meeting in Chicago in April 2017. The founding president of the society is Stephen Barr, a professor of physics at the University of Delaware who frequently writes for popular audiences, including the books Modern Physics and Ancient Faith (2003) and The Believing Scientist: Essays on Science and Religion (2016). The society proposes to offer a witness “to the harmony between the vocation of scientists and the life of faith.” What such a harmony entails is not, however, a scientific question; it is a question for theology. And, like all theological questions, it necessarily involves philosophical analysis.
The Philosophy of Nature
A Catholic scientist cannot avoid theological and philosophical engagement. There is a sense, of course, in which no scientist functions in a theological or philosophical vacuum. A fundamental feature of the Catholic tradition is its explicit recognition of the theological and philosophical contexts of all human activity, and not just of the activity of scientists. Nevertheless — once again this is a feature of Catholic thinking — there is a special importance for scientists to grasp this truth since all our knowledge begins with sense experience.
My focus in these comments is not on ethics — what to do with our knowledge — but, rather, on what it is that a scientist knows. Is there some understanding of scientific knowledge that is embraced by a Catholic scientist precisely because he or she is Catholic? Surely, such knowledge would not be in contradiction to or a replacement for what the natural sciences tell us about the world. Indeed, it is a fundamental principle of Catholicism that God is the author of all truth, and hence whatever truths human reason discovers about the world cannot contradict what God’s revelation discloses. The principle is easy to state, but it is not always easy to be sure what reason discovers and what faith reveals. A Catholic scientist can help fellow scientists see that Christian revelation does not challenge the truths of science, and he or she can help Christians see that they ought not to fear science as a threat to religious belief. These principles do not eliminate all tensions and conflicts throughout history or today. But they do set the benchmark for how one can respond to such controversies.
How should a Catholic scientist respond to claims that some contemporary cosmological theories — which include an eternal series of big bangs or multiverse scenarios in which our universe is but one of an infinite number — call into question (if not deny) the doctrine of creation? What about the fact that chemical analysis suggests that the bread and wine do not change during the Mass, when the doctrine of transubstantiation affirms that they really become the body and blood of Christ? Or what about the claims of evolutionary biology that human beings exist in biological continuity with the rest of the living world and do not represent any qualitative difference within that world, when revelation tells us that men and women are created in the image and likeness of God? What of the view that the natural sciences are sufficient to explain all that needs to be explained in the world (with no need to appeal to divine causality), when God’s providence is constantly at work in all that happens?
For a scientist who happens to be Catholic, these and related questions might prove personally vexing but could, perhaps, simply be left to others to discuss. But a Catholic scientist, I think, has an obligation to think systematically about them. Such engagement requires the Catholic scientist to integrate his or her own work into a more general science of nature, traditionally known as the philosophy of nature. The importance of the philosophy of nature — and the metaphysics that follows from it — has always been a key insight of Catholic thinkers, especially St. Thomas Aquinas (1225–1274) and his teacher, St. Albert the Great (1200–1280). The philosophy of nature is not the philosophy of science (a more or less modern discipline). Rather, it concerns questions such as the nature of change, of various kinds of cause, of time, of life, of purposes in nature, of the reality of the soul, and similar topics. The philosophy of nature is not theology and it is not limited to Catholic scientists. In fact, it is important for any scientist (believer or non-believer) to think clearly about this more general science of nature, of which his or her own specialty is a part. But Catholic theology puts a special emphasis on the importance of a sound philosophy of nature in order to resolve many of the questions to which I have already referred. This ought to serve as an impetus for any Catholic scientist to study the philosophy of nature.
Science, Naturalism, and the Knowledge of God
There is a widespread acceptance today, especially in scientific circles, of a materialistic natural philosophy: that there is nothing more to the natural order than material or physical entities.
Materialism is often expressed in various forms of mechanism that considers living things only as machines so that, finally, there really is no difference between artifacts and organisms. For this philosophy of nature, free will, rationality, consciousness, and the soul are reduced to mere illusions or perhaps epiphenomena of material reality. Despite challenges to science offered by various forms of fundamentalism and biblical literalism, the more significant threat comes from an exclusively materialist understanding of nature. The latter eliminates the distinction between the living and the non-living, reduces change to the rearrangement of material entities, and eviscerates nature of any intrinsic principles.
The Catholic scientist ought to recognize the materialist philosophical framework in which much of contemporary science is set forth and then use resources from the Catholic tradition to challenge the presuppositions of such a philosophy. An initial motivation to reject materialism and mechanism may come from faith, but the analysis of the claims must come from the discipline of the philosophy of nature. Since discourse in the philosophy of nature does not require faith, the Catholic scientist can engage in such discourse with other scientists who do not share this faith.
As a more general science of nature than the individual empirical sciences, the philosophy of nature depends on those sciences, but also requires an elevated level of analysis. The Catholic scientist is especially well prepared to enter this intellectual arena. However, he or she must first be aware of the arena and then learn how to navigate in it. There are historical sources to aid in this enterprise, such as Albert the Great and Thomas Aquinas. There are also more recent authors, such as Benedict Ashley, William Wallace, and Michael Dodds.
Most of the challenges to an understanding of the relationship between science and faith come from a kind of “totalizing naturalism” that affirms that the natural sciences tell us everything that can be known about the world. Any appeal to God is to be rejected as superfluous. Too often the choice presented is whether or not to explain a particular feature of the world in terms of natural causes or in terms of divine causality. The more one appeals to nature, the less, it seems, one appeals to God’s agency, and vice versa. It is the province of the natural sciences to discover causes in the natural order. And the Catholic scientist, like any other scientist, seeks to discover the natural causes that explain the phenomena revealed through the observation and investigation of nature. Albert the Great, who was named patron saint of scientists by Pope Pius XII in 1941, put it this way: “In the natural sciences we do not investigate how God the Creator operates according to His free will and uses miracles to show His power, but rather what may happen in natural things on the ground of the causes inherent in nature.”
Albert’s famous student Aquinas pointed out that there is an autonomy and integrity to nature such that there are real causes operating: acorns really do cause oak trees, hydrogen and oxygen are causes of water, and so forth. God causes creatures (animate and inanimate) to be causes of their own proper effects. God’s causality is so powerful, so utterly transcendent, that He can be the complete cause of all that is and happens, and creatures, too, are the causes of what they do. It is by examining what it means for God to be the Creator — an examination in metaphysics and theology — that we are able to come to some understanding of how “to be created,” that is, to be completely dependent upon God, is also an affirmation of individual autonomy, of having one’s own nature from which one’s characteristic behavior flows. In fact, there can be no real autonomy in existing things were it not for the fact that they are created ex nihilo. Creation is not some distant event; it is the ongoing causing of the whole reality of whatever is. There can be no nature — and hence no science of nature — without there being a Creator.
The Catholic scientist has a crucial role to play in helping people recognize that God is revealed in nature; the Creator’s footsteps are seen, as it were, in the created order. The theological emphasis on the philosophy of nature was affirmed in 1870 in the First Vatican Council’s solemn proclamation that:
God, the source and end of all things, can be known with certainty from the consideration of created things, by the natural power of human reason…: “ever since the creation of the world, his invisible nature has been clearly perceived in the things that have been made.” (Romans 1:20)
The route from creatures to Creator begins with the natural sciences, but then passes through the philosophy of nature and, ultimately, metaphysics.
In a well-known letter written in 1988 to George Coyne, S.J., then the director of the Vatican Observatory, Pope John Paul II referred to the dynamic relationship between science and faith: “Science can purify religion from error and superstition; religion can purify science from idolatry and false absolutes. Each can draw the other to a wider world, a world in which both can flourish.” In this wider world, the Catholic scientist, supported by philosophical and theological analysis, can help Catholics see that the tenets of their faith are not called into question by the extraordinary advances of science. The harmony between faith and science does not destroy the special characteristics of each — yet it does affirm a real unity in our understanding of both Creator and creatures.