Last November several newspapers and websites around the world led with a whimsical headline: “ET Phone Rome!” The accompanying stories reported that the Vatican was hosting an international conference to study the possibility of extraterrestrial life — life on other planets.

Many who read the report, Catholics included, were surprised that Rome would be concerned with such matters. Yet the Vatican has long shown a keen interest in astronomy and related studies, and it even maintains its own observatory. In fact, more than one Vatican astronomer has observed publicly that the existence of extraterrestrial life is a possibility, and that discovery of such life would not contradict or undermine the Church’s teaching. 

Has the Church spoken definitively about the possibility of extraterrestrial life — and extraterrestrial intelligent life (or ETI) in particular? 

An Ancient Debate  

The notion of ETI has its roots, not in modern science fiction, but in ancient Greek philosophy. Beginning in the fifth century B.C., the atomist philosophical tradition proposed the existence of multiple “worlds,” some of them inhabit ed. (By “world” — Greek, cosmos — they meant not planets within our one universe, but multiple universes.) A rival philosophical tradition, represented most famously by Plato and Aristotle, insisted that only one universe could exist. 

The sixth-century mathematician Pythagoras concluded that intelligent life exists in places beyond earth but within our universe. Plutarch, in the first century, wrote a treatise on the moon that explored in detail the common arguments presented in his day for and against the existence of lunar inhabitants. 

Following Aristotle’s philosophical arguments, the medieval Scholastic tradition (including St. Thomas Aquinas) tended to argue that God had created only one universe, because they considered it a logical contradiction to think otherwise. But in 1277 Etienne Tempier, the bishop of Paris, in a list of heresies, publicly condemned the belief “that the First Cause [God] cannot make many worlds.” To Tempier, such a notion seemed to deny God’s omnipotence. 

In the following centuries several Catholic theologians argued that God could in fact create other worlds if he chose to do so, such as the 14th-century French philosopher-theologian Nicole Oresme (later bishop of Lisieux). Many of those involved in the debates about the “plurality of worlds,” as they called the notion, did not address the specific issue of life in other universes.  

But by the time of the Renaissance and Reformation, philosophers and scientists who gave thought to the matter began to shift the focus of attention from debates about multiple universes to debates about multiple planets like earth, along with the corresponding issue of life on these planets. 

Notable among them was the 15th-century German philosopher-theologian Cardinal Nicholas of Cusa. In his treatise “Of Learned Ignorance,” the cardinal concluded that God had created various kinds of life throughout the universe “lest so many places in the heavens and on the stars be empty.” He went on to speculate that in the “solar regions” live inhabitants who are more “brilliant, illustrious and intellectual” than the human inhabitants of earth. 

Many Thinkers Thought 

In the Protestant Reformation, Calvinist theologian Lambert Daneau and Lutheran theologian Philipp Melanchthon both attacked the notion of inhabited worlds beyond earth. Melanchthon insisted that the Bible was silent about the creation of human beings anywhere except on earth, so other planets must not be inhabited. 

Two Catholic theologians — the Italian Dominican Tommaso Campanella and the French Minim Friar Marin Mersenne — responded specifically to these concerns. Silence in Scripture about extraterrestrial life, they maintained, was no proof that it didn’t exist. Scripture is in fact silent about many things we know for certain to exist, including the planets themselves. 

Since many Catholics shared Melanchthon’s position on the matter, these two theologians also noted that the Church’s magisterial tradition allowed for such a possibility. The question had not been addressed by an ecumenical council, and there seemed to be no apostolic tradition relevant to the issue. 

The celebrated Catholic astronomer Galileo Galilei left open the question of whether nonhuman ETI might exist. Other well-known figures of this period thought it a certainty, including the Italian Dominican philosopher Giordano Bruno and the famous Protestant astronomer Johannes Kepler. 

Admittedly, Galileo, Campanella and Bruno all ran into trouble with Church authorities for some of their teachings. Notably, the specific notion of life on other planets was not among the beliefs that the Church condemned.  

Jesuit-trained Bernard le Bovier de Fontenelle, secretary of the French Academy of Sciences, wrote of nonhuman races created by God and inhabiting the planets. He insisted that the existence of such ETI were against neither reason nor Scripture, and his work found an extremely wide readership among educated people of his day. 

A number of other thinkers of this era took up the issue and concluded that ETI was possible, probable or even certain. Among the best-known were Voltaire, René Descartes, Immanuel Kant, Christiaan Huygens, John Milton and Alexander Pope. Their influential writings helped to popularize the idea of extraterrestrial intelligence throughout the Western world. 

Those who considered the theological as well as scientific reasons to affirm ETI typically offered two rationales. First, the existence of ETI would glorify God and demonstrate the fullness of His creative power. Second, if our planet was created for our use, and the visible heavens were created to lead human intellects to wonder at God’s goodness, then the vast expanses of the cosmos hidden to us must have been created for the sake of beings on other planets. 

19th-Century Debates

In the 19th century, the implications of ETI were enthusiastically debated on both sides of the Atlantic Ocean. In 1861, Abbé Joseph Émile Filachou of Paris published a book rejecting the idea of ETI on the grounds of both science and Catholic faith. 

Two years later, however, Père Joseph Félix, a popular preacher in Paris, declared to an audience of thousands in Notre Dame Cathedral that the notion of extraterrestrial life presented no problems for Catholic doctrine. “Put into the [astronomical] world as many populations as you please, under such degree of material and moral temperature as you wish to imagine; Catholic dogma has here a tolerance that will astonish you and ought to satisfy you,” he said. 

In 1865 and 1866, the French thinker Monseigneur de Montignez published nine essays on the subject. The fourth essay argued that “the blood which flowed out at Calvary has gushed out on the universality of creation.” He also insisted that the full meaning of many scriptural passages can be understood only in light of intelligent life on other worlds. 

More than a dozen other French clerics followed suit, as well as a few Catholic laymen. Of particular note is the remark by the priest-theologian Theophile Ortolan that “the Congregation of the Index [the forerunner of the Congregation for the Doctrine of the Faith], consulted on this point, has officially responded” that there is no contradiction between the notion of ETI and the Catholic faith. 

Also noteworthy during the late 19th century is the work of Father Angelo Secchi, a director of the Vatican Observatory. Secchi wrote more than once about “the other innumerable beings, blessed by the hand of the Omnipotent,” and his statements were quoted by Catholics around the world. One of Father Secchi’s astronomy students, the German Father Joseph Pohle, took the same position and adopted arguments from Scholastic philosophy to support it. 

Father Pohl crossed the Atlantic to teach at The Catholic University of America (CUA) from 1889 to 1894. A colleague there, Paulist Father George Mary Searle, was a convert from the Unitarian beliefs he had held at Harvard. As observatory director at CUA, Father Searle entered the ETI debate, allowing that extraterrestrial life would not contradict the Catholic faith. However, he thought habitable conditions elsewhere in the universe were unlikely. 

One of the more interesting theological arguments proposed at this time for the existence of extraterrestrial intelligence came from Msgr. Januarius De Concilio, theology professor at Immaculate Conception Seminary in New Jersey. He believed that the immense distance in intellect between human beings and the angels suggest that God would create intermediate species to fill in the gap, and these species would be ETI. This argument was challenged, however, by the Jesuit Thomas Hughes, on the faculty of St. Louis University. 

At the close of the century, the Canadian curé of Fort Kent, Maine, Abbé Francois Xavier Burque, had become disconcerted that Canadian seminary teachers were espousing the possibility of extraterrestrial life. In 1898, he published a book that concluded ETI can be reconciled with Catholic teaching on the Incarnation and redemption “only with extreme difficulty.” Extraterrestrials would almost certainly be sinners, requiring that Christ be crucified multiple times for their salvation — an idea that he believed contradicts Hebrews 9:25-26, which says that Christ has not had to “suffer repeatedly,” but suffered “once for all.” 

Still Unresolved 

Throughout the 20th century and on into the 21st, the ETI debates have continued, with Catholic thinkers taking a variety of positions, just as they have from the beginning of the discussion. Meanwhile, no magisterial document from the Church has provided a definitive theological statement on the matter. At most we have the 19th-century ruling of the Congregation of the Index, cited by Father Ortolan, that there is no opposition between the dogma of the Church and the idea that extraterrestrial intelligence exists. 

How can the issue finally be settled? Perhaps nothing short of a public, thoroughly documented encounter between earthlings and aliens (or their relics) will be conclusive. In the meantime, unless the magisterium should break its silence on the issue, Catholics are free to argue and speculate within the confines of faith and reason. TCA 

Paul Thigpen, Ph.D., is director of CHResources, the publishing outreach of the Coming Home Network, whose mission is to help non-Catholic clergy come home to the Catholic Church. He is a past editor of TCA.

Christ and Extraterrestrial Life (sidebar) 

If intelligent beings exist on other planets and are not descended from Adam, then what is their relationship to Christ? Are they fallen or unfallen? That is, do they need a Savior? If so, can Christ, the “last Adam” who saves the descendants of the “first man, Adam” (1 Cor 15:45) be their Savior if they are not of Adam’s race?  

Has God the Son perhaps become incarnate more than once, taking on the “flesh” of races on other planets, to make salvation possible for them as well? 

Some earlier thinkers had in fact raised such issues. The 15th-century Scholastic philosopher William Vorilong wondered “whether Christ by dying on this earth could redeem inhabitants of another world.” He answered the question in the affirmative, because he concluded that Christ could not die again in another world. 

René Descartes had reasoned that “the mystery of the Incarnation and all the other advantages which God bestowed on man do not preclude the possibility that He might have granted infinitely many others, very great, to an infinity of creatures.” 

The Lutheran reformer Philipp Melanchthon had concluded that Christ could not have died and been resurrected on other worlds. But a late 18th-century treatise, probably written by Abbé Jean Terrason, took the opposing position: God the Son might well have been incarnated on many worlds, with the result that He would have many creaturely natures, though only one divine nature. 

In all these cases, Christians had drawn their conclusions according to the dictates of faith and reason as they understood them, always with an eye to keeping reason within the bounds of faith. But just before the 19th century arrived, some skeptics posed these same questions with the goal of undermining the Christian faith, most notoriously the English writer Thomas Paine. 

Paine insisted that the plurality of worlds (which he affirmed) was incompatible with the Christian notion of the Incarnation. Why, he asked, would “the Almighty, who had millions of worlds equally dependent on His protection … quit the care of all the rest and come to die in our world”? 

On the other hand, he reasoned, if an Incarnation took place on every fallen world, then the Son of God would “travel from world to world, in an endless succession of death.” The Catholic political philosopher Comte Joseph de Maistre responded to Paine’s claims by suggesting that Christ’s earthly Incarnation was a sacrifice whose power reached throughout the cosmos. He quoted the ancient Catholic theologian Origen: “The altar was at Jerusalem, but the blood of the Victim bathed the universe.”