The Enriching Complementarity of Faith and Science

“By faith alone do we hold, and by no demonstration can it be proved, that the world did not always exist,” writes St. Thomas Aquinas, implicitly making a claim about the proper relationship between faith and science.¹ The public in general and scholars of various fields in particular often see this relationship as fraught with challenges. The greatest opposition to dialogue and reconciliation between science and faith is often seen as coming from individuals who embrace science but reject religion, as well as those who embrace religion but reject science. But those who embrace both religion and science can also present an obstacle to such reconciliation, an obstacle that can consequently prevent the two former groups from entering into meaningful dialogue. Such obstruction often takes the form of well-intentioned but perhaps overzealous appropriation of scientific theories as proof of religious beliefs. Such appropriation is meant to show the compatibility of science and faith, but can be disconcerting for those who embrace science but not faith, thereby hindering dialogue with that group. Those of us who do embrace both science and faith first need to grasp and internalize the proper relationship between those two domains in order to communicate that relationship to others.

The place to begin a dialogue between science and faith is with those who accept, at least in principle, both science and faith. I consider myself one such individual, having received a bachelor’s degree in physics followed by a master’s degree in theology. Yet I have discovered it is not enough simply to embrace and accept both science and faith; we need to understand the proper relationship between them for ourselves before being able to engage others. Science and faith have different yet complementary domains, and we must be cautious not to misappropriate one into the other for the sake of dialogue, but rather respect the separate domains and embrace the proper complementarity between those two domains or risk sabotaging dialogue. In contemplating this issue, I have found inspiration in examining the development of the theory of the Big Bang and its reception among Catholics, especially its early proponent, the Belgian priest and physicist Monsignor Georges Lemaître. Such reflection has led me to see faith and science as two complementary disciplines that mutually enrich one another through challenging questions.

In 1927, following upon Einstein’s General Theory of Relativity, Lemaître proposed that the universe could be expanding.² Edwin Hubble effectively confirmed this postulation through observations in 1929 leading to Hubble’s Law. In 1931, Lemaître built upon Hubble’s discovery by developing the Big Bang theory, originally called the primeval atom. Lemaître suggested that the expansion of the universe could be traced backwards in time to a moment when all matter existed within a particular point, now called a “singularity,” at which laws of physics break down. This point is generally considered the literal beginning of space and time, before which it is impossible to make observations. A variety of theories do provide for something prior to this singularity, which may take the form of a series of universal bangs and contractions, a theory Lemaître found to have “poetic charm,” describing the universe as a “phoenix.”³ It is generally not considered possible to make a direct observation past that singularity.

When a Christian hears about the Big Bang, especially described as the literal beginning of space and time, it is hard not to think of the traditional understanding of the Genesis account describing God creating ex nihilo. In fact, some scientists were originally skeptical of Lemaître’s proposal, worrying he may have been motivated by religious doctrine.⁴ Pope Pius XII exacerbated this skepticism in an address to the Pontifical Academy of Sciences in 1951. Laudably attempting to demonstrate Catholic support of modern scientific developments, the Pope stated, “it would seem that present-day science, with one sweeping step back across millions of centuries, has succeeded in bearing witness to that primordial ‘Fiat lux’ uttered at the moment when, along with matter, there burst forth from nothing a sea of light and radiation, while the particles of chemical elements split and formed into millions of galaxies.”⁵ The Pope was attempting to show that Christianity is not antithetical to scientific developments. In fact, he argues, these developments seem to support the Faith.

The Pope’s remarks disturbed Lemaître, according to a student in one of his graduate seminars.⁶ Lemaître believed the theory of the primeval atom was still in its infancy. To declare truths of faith to be dependent upon an immature scientific theory was dangerous and reckless. More importantly, Lemaître did not believe his theory necessarily indicated God’s action, nor should it. Lemaître was concerned that physicists would be hesitant to support the Big Bang if they thought it was motivated by religious doctrine. He explained this issue at a physics conference in 1958, hoping to undo damage seemingly caused by the Pope’s misappropriation:

As far as I can see, such a theory remains entirely outside any metaphysical or religious question. It leaves the materialist free to deny any transcendental Being. . . . For the believer, it removes any attempt to familiarity with God. . . . It is consonant with Isaias speaking of the ‘Hidden God’ hidden even in the beginning of the universe. . . . When Pascal tries to infer the existence of God from the supposed infinitude of Nature, we may think that he is looking in the wrong direction.⁷

Lemaître recognized a genuine danger in inappropriately interpreting scientific discoveries from a religious perspective, and yet it is a natural temptation for people of faith. In order to promote stronger cooperation and dialogue between faith and science, it is necessary to identify and address this temptation, as well as propose a proper mode for expressing the relationship between scientific theories and religious doctrine. Lemaître’s elaboration of the relation between the two disciplines is especially valuable. His comments illustrate how a person of faith should approach the Big Bang in particular and scientific discoveries in general.

From an early age, Lemaître seems to have perceived that science and religion have separate yet complementary domains. In 1903, at the age of nine, Lemaître decided to be both a physicist and a priest. In a 1933 interview with the New York Times, he recalled, “exactly at the same time [as when he chose to be a physicist], actually in the same month as I remember it, I made up my mind to become a priest. . . . There were two ways of arriving at the truth. I decided to follow them both.”⁸ Lemaître saw a single source of truth, yet different ways of approaching this truth. Each method reveals different aspects of that truth, and both need to be pursued and respected to gain a full appreciation of truth.

In the same interview, Lemaître commented on the perceived conflict between these two disciplines: “The conflict has always been between those who fail to understand the true scope of either science or religion. For those who understand both, the conflict is simply about descriptions of what goes on in other people’s minds.”⁹ For Lemaître, there is no intrinsic conflict between science and faith; the conflict can be reduced to people of science and people of faith misjudging the domain of each discipline. He continues, “Do you know where the heart of the misunderstanding lies? . . . It is really a joke on the scientists. They are a literal-minded lot. Hundreds of professional and amateur scientists actually believe the Bible pretends to teach science. This is a good deal like assuming that there must be authentic religious dogma in the binomial theorem.”¹⁰ Lemaître’s critique could just as easily be leveled at people of faith. For Lemaître, an appropriate approach to theology means realizing it does not attempt to provide scientific information. Likewise, the domain of science does not contain religious doctrine.

While they are distinct fields, an understanding of science can and should lead to a deeper appreciation of theology, and vice versa. Lemaître continues in that interview, “[Once a scientific field has matured,] the sense that this is a morally ordered universe will be inculcated. As soon as any science passes the mere stage of description it becomes a true science. Also it becomes more religious.”¹¹ A scientific discipline never leads to religious knowledge, but it can lead to and support a religious sentiment. One can see beauty in the Big Bang and wonder at the gift humanity has in being able to understand cosmic mechanics, even if one does not believe in God.

Lemaître approaches this relationship principally as a twentieth-century scientist with theological training. A similar approach occurs within my own Dominican tradition in the thought of Thomas Aquinas, who approaches the question as a thirteenth-century theologian. Aquinas complements Lemaître’s elaboration by adding further elements of faith. Combining these two thinkers helps describe an appropriate religious approach to the Big Bang.

Lemaître’s expressed attitude toward the Big Bang is consistent with Aquinas’s teaching about the possible eternity of the universe. Aquinas taught that human reason could demonstrate neither the eternity nor the non-eternity of the universe, contrary to other theologians of the time, such as Bonaventure.¹² Aquinas would be satisfied with Lemaître’s attitude toward the Big Bang: this theory was developed using reason and goes to some beginning of time. But one cannot demonstrate this moment to be the absolute beginning of time, nor can one demonstrate that the universe existed prior to this point. Even less can one prove that God brought about this Big Bang. There is a limit to human reason. Aquinas affirms God’s creation of the world as an article of faith, not an article of reason, and that articles of faith cannot be proven because they are “conviction of things not seen.”¹³ Like Lemaître, Aquinas would not want to appropriate scientific theories for religious purposes, as if faith could be scientifically proven. The domains are separate yet complementary.

Lemaître’s and Aquinas’s position reveals that, for the scientist, the Big Bang theory demonstrates the power and limits of human reason. All people, including scientists, can awe at the power of the human mind to understand the dynamics of the cosmos. Scientists also need to realize that the human mind cannot come to comprehend the entirety of the universe. Some kind of faith is necessary. At a minimum, one has faith that scientific laws apply throughout the universe and do not vary randomly. Such faith leads one to believe that we can postulate the Big Bang. Scientific discoveries such as the Big Bang do lead to a religious sentiment employing awe and faith, even if one does not believe in God. This realization is a point of commonality between all people and could, perhaps, open doors to collaboration and dialogue.

Even more important for furthering dialogue between faith and science is what Lemaître’s and Aquinas’s position can teach Christians. A Christian can look at the Big Bang theory and feel awe at the human capacity to understand the universe. It is truly a gift of God to be able to hold the truths of the cosmological structure within our own minds. This should lead to great respect for creation itself. We see the relationship God has established, for us to “have dominion” over creation (Gen 1:28). Such dominion does not mean we possess absolute control over creation, but that we are placed as creation’s stewards. Understanding creation through science should lead to a greater appreciation of the universe and hopefully inspire us to be good stewards of God’s gifts.

Perhaps most important for Christians to learn from Lemaître and Aquinas is the necessity of having a robust dependence on faith as an essential aspect to the Christian life. We naturally desire to have proof of our faith and signs from God. But what we actually need is to trust in God. The central mystery of the Christian faith, the Resurrection of Jesus, is scientifically and historically unverifiable. We have post-Resurrection testimony and records of a first century Jesus-centered movement that give credence to the Resurrection, but no way to prove that event. What is required is faith and trust in God. Science cannot and should not prove the Faith, because it then ceases to be faith. We must acknowledge what God says through Isaiah: “As the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts” (Is 55:9). We should resist appropriating scientific theories like the Big Bang, and we should actually hope that scientific developments not prove elements of the Faith in order to preserve the beautiful act of faith.

By resisting the temptation to appropriate science as proof of faith, we can allow scientific developments to encourage greater dependence upon faith and lead us to develop a more mature yet childlike faith (see Mt 18:3). When we become too comfortable with some reality or belief, a scientific development can offer a challenge. In response, we learn not to depend upon objective proofs of faith, but instead to have subjective encounters of trust in God. The Big Bang offers this kind of challenge. A naive Christian interpretation of the Big Bang is to see it as proof of creation ex nihilo, an article of faith. A more mature interpretation, however, following upon Lemaître and Aquinas, acknowledges the possibility of the eternity of the universe, from a scientific perspective. This possibility and ambiguity should lead to a deeper understanding of divine creation. We realize that the book of Genesis is not a historical and scientific document, but instead expresses the story of God’s care for the universe. In resisting the temptation to interpret the Big Bang as religious doctrine, we acknowledge doctrines of faith truly as faith over which we do not have control. We acknowledge our own limitations and finitude, and we resist the audacious claim of scientifically proving God who is beyond scientific proof. Other scientific developments can present similar challenges and encourage us to encounter a deeper meaning within Scripture beyond the surface-level literal. For example, theories of human evolution can provide challenges to the way in which we elaborate the traditional Catholic doctrine of Original Sin and monogenesis. We should be elated about such a challenge and should strive to see our religious doctrine truly as pertaining principally to faith and the human encounter with God.

Understanding the proper role and nature of faith in our lives is essential to the Christian life. Part of how I see my role and my vocation is to communicate how to trust in God with mature, childlike trust. Rather than looking for scientific discoveries to prove our faith and disprove atheists, we might instead hope for scientific discoveries to challenge our faith, in order to give us an opportunity for detachment from material images of God and to abandon ourselves more into that childlike trust. Science should inspire that childlike sense of wonder and awe at the amazing capacity God has given us to understand his amazing and rational creation. It should also inspire in us the childlike trust in his care, providence, and fidelity. When we as Christians are able to understand how our faith and science complement and enrich one another, we are then in a stronger position to demonstrate that there is no need for reconciliation between faith and science, and we are in a stronger position to collaborate with scientists.

An earlier version of this essay won the seminarian award for the Re-Engaging Science in Seminary Formation international essay competition, funded by the John Templeton Foundation at John Carroll University.