In an address to the Pontifical Academy of Sciences in 1951, Pope Pius XII remarked that “true science discovers God in an ever-increasing degree—as though God were waiting behind every door opened by science.” One such door had been opened by recent developments in cosmology, championed in part by Georges Lemaître, a Belgian priest and one of the original proponents of what is now called Big Bang cosmology.
Western history has witnessed frequent discussions of the relationship between the natural sciences and religion; one continuing chapter in that history concerns creation and cosmological theories about the beginning of the universe. One of Lemaître’s contributions was his insistence that the beginning of the universe, to which his cosmology pointed, ought not to be identified with the moment of creation.
Pius XII had a longstanding interest in the natural sciences, especially astronomy; as Eugenio Cardinal Pacelli, he had been a special member of the Pontifical Academy of Sciences. His encyclical Humani Generis (1950) had offered commentary on modern evolutionary theory and its implications for philosophical and theological conceptions of human nature.
In his 1951 address, Pius observed that philosophy (both the philosophy of nature and metaphysics) is able to discover God, but that such discovery depends upon the “concrete realities established by the senses and by science.” The experience of the ancients provided human reason with sufficient arguments to demonstrate the existence of God—and now, thanks to the great expansion of our knowledge of nature, “the vestiges of the Eternal One are discernible in the visible world in an ever more striking and clearer light.” That with reason alone one can know God exists is traditional Catholic teaching.
In a tour d’horizon of the natural sciences as they existed in the post-war world, Pius emphasized two topics: the mutability of things, including their origin and their end, and “the teleological order which stands out in every corner of the cosmos.” He reminded his audience that modern physics had discovered examples of mutability in the universe not dreamt of before, on the level of both the macrocosm and the microcosm: “Thus physics has provided a multiplicity of empirical facts which are of tremendous assistance to philosophical reasoning.” Pius argued that science had broadened and deepened the empirical foundation on which rests the argument from the mutability of the world to “the existence of an Ens a se [a Being that exists of and through itself], immutable by His very nature.”
When the pope turned to cosmology and the question of the origin and development of the universe, he cited Edwin Hubble’s discoveries, which pointed to an expanding universe of finite age. He then drew a conclusion concerning such discoveries and the Christian doctrine of creation:
[I]t 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. . . . Thus, . . . it has confirmed the contingency of the universe and the well-founded deduction as to the epoch when the cosmos came forth from the hands of the Creator. Hence creation took place in time. Therefore, there is a Creator. Therefore, God exists!
Commentators on the pope’s speech, in noting what they consider an ill-advised leap from cosmology to creation, often overlook the fact that he had qualified his enthusiasm for the philosophical and theological implications of the cosmology that referred to a universe expanding from a primordial state:
[I]t is quite true that the facts established up to the present time are not an absolute proof of creation in time. . . . The pertinent facts of the natural sciences, to which We have referred, are awaiting still further research and confirmation, and the theories founded on them are in need of further development and proof before they can provide a sure foundation for arguments, which of themselves, are outside the proper sphere of the natural sciences.
Pius did not claim that the new cosmology provided a scientific proof for the absolute beginning of the universe, nor that it constituted a cosmological confirmation of creation.
We must distinguish between specific arguments about creation based on cosmological theories concerning the beginning of the universe, and broader arguments about the existence of God based on our knowledge of nature and its processes. Further, knowing that God exists is not the same as knowing that God is the Creator.
What cosmology might be able to disclose about the creation of the universe was a topic for the leading Catholic cosmologist of the mid-twentieth century, Georges Lemaître (1894–1966)—a member of the Pontifical Academy of Sciences, though he was not present when Pius spoke. In the late 1920s and 1930s, Lemaître, working in the context of Einstein’s theory of general relativity and Edwin Hubble’s claims that distant galaxies were moving away from the Earth, concluded that the entire universe was expanding. In a paper published in Nature in March 1931, the British astronomer Sir Arthur Eddington (with whom Lemaître had worked at Cambridge) suggested an extrapolation of an expanding universe backward into the past. Eddington wrote that such a scenario, which seemed to indicate a beginning to the universe, was “philosophically repugnant.” Why? Because indicating a beginning to the universe would involve, so he thought, something beyond the realm of scientific explanation, and perhaps indicate a confusion between physics and theology. Einstein considered such an initial “singularity” a metaphysical concept, not a physical one.
In the May 9, 1931 issue of Nature, Lemaître responded that the notion of a beginning was not repugnant: The beginning of space-time could be understood as the disintegration of a single quantum, what he called the “primeval atom.” It is a “beginning” that would have occurred “a little before the beginning of space and time.” Lemaître would eventually publish this theory in a book, The Primeval Atom Hypothesis (1946). Soon thereafter, another British astronomer, Fred Hoyle, would coin what he considered a derisive phrase for such a beginning: the Big Bang.
From the earliest discussions of the theory of an expanding universe with a finite past, concerns arose about its philosophical and theological implications. They endure to the present, as different scholars use cosmological theories either to support or to reject the idea of creation. Pope Pius XII’s 1951 speech was an example of the former. In the late 1950s and 1960s, scholars in the Soviet Union were prohibited from teaching Big Bang cosmology, as it was considered “theistic science.”
But Lemaître suggests how we might begin to resolve the confusion about creation and cosmology. His initial interest in a primeval atom from which the universe was expanding had a religious context. In letters written to a friend in 1916 and 1917, he described his interest in interpreting the opening verses of Genesis. Nevertheless, he always resisted the conclusion that the “natural beginning” of the universe ought to be identified with the creation of the universe.
By the 1950s, Lemaître had developed a clear understanding of the methodological separation between theological and cosmological levels of discourse, a clarity not always present in his early years. In an essay written after World War II (but left by Lemaître in manuscript), he noted that the initial expansion of the universe from a primeval atom might be referred to as “a beginning.” But he continued:
I do not say a creation. Physically it is a beginning in that sense that if something has happened before, it has no observable influence on the behavior of our universe, as any feature of matter before this beginning has been completely lost by the extreme contraction at the theoretical zero. A pre-existence of the universe has a metaphysical character. Physically everything happens as if the theoretical zero was really a beginning. The question if it was really a beginning or rather a creation, something starting from nothing, is a philosophical question which cannot be settled by physical or astronomical considerations.
Lemaître was in Rome just before the 1952 Eighth General Assembly of the International Astronomical Union, at which Pius XII was to speak. In a meeting with the pope, Lemaître expressed concerns about using his cosmological hypothesis to support the view that the world is created. When the pope spoke to the meeting he did not mention the new cosmology, and never again did he publicly refer to any philosophical or theological implications of this cosmology.
We might guess what Lemaître told Pius from Lemaître’s communication to a conference in 1958. Here he notes that his primeval atom hypothesis “remains outside any metaphysical or religious question. It leaves the materialist free to deny any transcendent Being. . . . For a believer, it removes any attempt in familiarity with God . . . [since God remains] hidden even at the beginning of the universe.”
There is a source of Lemaître’s general distinction between creation and cosmology, a source with which he probably became familiar during his philosophical studies at the University of Louvain, as part of his preparation for the priesthood. Under the leadership of Cardinal Désiré Mercier, Louvain was a center for the revival of Thomistic philosophy and theology. Thomas Aquinas continues to offer important insights into the doctrine of creation, and wise counsel concerning the relationship among the natural sciences, philosophy, and theology.
When Lemaître says that the question—whether the beginning of the universe to which his theory points is creation—is “a philosophical question which cannot be settled by physical or astronomical considerations,” he echoes, in part, Thomas’s judgment that whether or not the universe has an absolute beginning cannot be determined by science. Thomas adds that philosophy itself cannot make such a determination. For Thomas, the temporal finitude of the world is exclusively a matter of revelation. In one of several places where he warns against using bad arguments to support conclusions that faith affirms, Thomas writes:
That the world had a beginning . . . is an object of faith, but not a demonstration of science. And we do well to keep this in mind; otherwise, if we presumptuously undertake to demonstrate what is of faith, we may introduce arguments that are not strictly conclusive; and this would furnish infidels with an occasion for scoffing, as they would think that we assent to truths of faith on such grounds.
Thomas’s thought contains an important distinction that Lemaître does not make. This is Thomas’s distinction between creation understood philosophically, in the discipline of metaphysics, and creation understood theologically, based on traditional interpretations of the opening of Genesis and solemn declarations of Church Councils. In a famous passage from his first magisterial analysis of creation, Thomas claimed that “not only does faith hold that there is creation, but reason also demonstrates it.” Thomas thought that by a systematic reflection on the distinction between what a thing is (its essence) and that it is (its existence), one could eventually come to know that there is an ultimate reality whose essence and existence are identical, and that this reality is the creative source of the existence of all that is. For Thomas, it was possible to use reason (in the discipline of metaphysics) to conclude that the universe is created.
The question of whether or not the universe has a beginning is not a part of the philosophical recognition that the universe is created. For Thomas, who believed that the universe had a beginning, an eternal universe (one without a beginning) would be just as much a created universe as one that had a beginning.
Like Lemaître, Thomas would warn against using cosmological arguments to support the view that the world is created. But I think that Lemaître links creation and temporal beginning too closely, so that he does not distinguish as clearly as Thomas does between creation understood philosophically and creation understood theologically. For those who think that to be created necessarily means to have a temporal beginning—and who, thus, either affirm or reject creation on the basis of whether or not there is a temporal beginning—Thomas offers a useful corrective. It is a corrective both to those who think that traditional Big Bang cosmology points to a beginning and therefore confirms creation, and to those who think that contemporary multiverse theories or an eternal series of “big bangs” deny a beginning and therefore deny creation.
William E. Carroll is Distinguished Visiting Professor at the School of Philosophy at Zhongnan University of Economics and Law in Wuhan, China.