St. Thomas Aquinas and the Aliens


Dermott J. Mullan, 404 Park Circle, Elkton MD 21921:



Summary: Aquinas’s discussion of the Hypostatic Union provides a framework for Christians to accept the possibility of alien life forms on other planets.



Is there life on other planets? This is a question that has interested people for centuries. For the past 40 years, since the technology of large radio telescopes became available, astronomers have been listening in to many nearby stars hoping to pick up signals from extra-terrestrial intelligent beings. The US Government funded these studies for a while, but when no signals were picked up after three decades of listening, taxpayer support dwindled and eventually dried up altogether. However, so broad was the interest in the Search for Extra-Terrestrial Intelligence (SETI) that private investors stepped in, and provided millions of dollars to fund the search, which continues to this day.


No signals have yet been received from an intelligent being by any radio telescope. Nevertheless, interest in the SETI research program remains at a high level. The program received a great boost in 1995 when astronomers in a very different field of research discovered a planet orbiting around another star. (The planet was not seen directly: it was discovered by detecting a “wobble” in the path of the star around which it revolves.) Since 1995, reports of the detection of planets around other stars have been coming in a steady rate.  As of July 1, 2002, the number of planets that are known to exist outside our solar system reached the 100 mark.


We live in exciting times. No-one yet claims that any of the 100 known planets around other stars actually contain intelligent life. But the mere fact that cold bodies (planets) exist in orbit around other stars opens up vistas of alien life that would have been regarded by many as mere science fiction only a few years ago.


The late Carl Sagan, an astrophysics professor at Cornell University, probably did more than any other scientist to popularize the possibility of life on other planets. Through his writings and his enormously popular TV show Cosmos, Sagan raised people’s awareness about the immensity of the universe and the vast possibilities that may exist for life to appear. And the ultimate would be for intelligent life to emerge somewhere in addition to Earth.


In 1985, Sagan published a book entitled “Contact” which describes in fictional form what might happen when evidence for intelligent life is first obtained. Sagan’s book is much more than fiction, however. It contains a respectful invitation to consider how science and religion might profitably interact. While the characters in the book are attempting to devise a response to the aliens, it is not only the scientists who are asked for an opinion: there is a place for religious figures to offer appropriate insights.


For a book authored by someone who was widely regarded as an atheist, it is remarkable how well balanced the characters in Contact actually are. There is no attempt to caricature the representatives of religion, or to portray the scientists as universally enlightened. There is a mixture of good and bad on both sides of the religion-science divide, just as there is in real life.


Underlying the whole novel is the question: is there really a God, and if there is, what can science say about this matter? Sagan does an intriguing job of outlining what a scientist might consider to be proof of God’s existence in the natural world. Since the physical world seems to be remarkably well described by mathematics, Sagan believes that God might want to prove His existence to scientists by hiding some sort of a pattern in one of the natural numbers, such as pi (the ratio of circumference to diameter of a circle). Perhaps, Sagan suggests, if one were able to calculate the value of pi to a trillion (or a quintillion, or more) decimal places, one might eventually come across a non-random pattern of numbers out there. For example, one might find a string of a few thousand sevens right next to each other. This lack of randomness would be (in Sagan’s opinion) a sure sign of intelligent design in the numbers of the natural world.


The main character in the book “Contact” actually performs this test, and the results of the test suggest that Sagan himself believed in the existence of God, despite a widespread perception of Sagan as a sort of “atheist-in-chief” among scientists.


The fact that Sagan was able to face squarely the question “Is there a God?” in his book is in marked contrast to what happened in the movie version of  Contact”. By the time the movie was being made, more than 10 years after the book appeared, Sagan was in terminal illness, and he was in no shape to control the screen-writers. The latter took liberties with the text, and as a result, the movie has a very different slant from the book. The movie is unabashedly anti-religion, or more specifically, anti-Christian. The Christian ministers in the movie are portrayed in quite negative terms.


Most telling of all, Sagan’s biographer Keay Davidson in the book “Carl Sagan: a Life” (1999) recounts an incident from the making of the movie which speaks volumes about certain people’s prejudices against religion. It seems that the screen writers wanted to have the principal religious character utter the following phrase after contact with the aliens is established: “My God was too small!”


However, the actor from whose lips this phrase was supposed to fall (Matt McConnaghty) refused to say it: he said that it was blasphemous, and would serve as a gratuitous insult to a great number of people who believe in God. As a result, the phrase does not appear in the movie.


Apparently, certain non-believers (including the screen writers for the movie “Contact”) are convinced that religious people have no room in their belief system for the possibility of life on other planets.  According to these folks, religious believers are supposed to imagine that God could have made life only on this planet where we live. And if we ever contact aliens, these folks apparently believe that this will spell the end for organized religion as we know it, because (in their view) no organized religion can accommodate a teaching about life on other planets. 


But in this regard, they are wrong. At least one theologian laid the groundwork for Catholics to accept alien life forms within the context of their faith. And we are not talking about a modern theologian who just happens to be keeping up with the current scientific literature. No: the theologian in question, Thomas Aquinas, did his work more than 700 years ago, while he was a theology  professor at the University of Paris.


What did Aquinas have to say that is relevant to life on other planets? To get an answer to this, let us consider his discussion of the Hypostatic Union. Since the first public profession of faith in Christ’s divinity (“Thou art the Christ, the Son of the Living God”: Matt 16, 16), Christians have known that there is more to Christ than meets the eye. In Christ, there is more than simply human nature: God is also somehow present in Him.


It took a few centuries for the Church to figure out how Christ can be simultaneously divine and human. But the fathers finally decided (at the Council of Ephesus, in 431) that the best human language could offer was to condense the mystery down to the so-called “Hypostatic Union”: two natures co-exist without confusion in one divine person.


When Aquinas discusses the Hypostatic Union in his Summa Theologiae, he makes the following point: it is inevitable that the Second Person of the Trinity possesses at least one nature (the divine nature). As long as there is only one nature and one person (let us refer to this as the one-in-one case), there is no mystery involved. The mystery enters when we go beyond the one-in-one to (say) the two-in-one teaching of Ephesus. It is indeed a profound mystery of the Catholic faith how Christ can be one Person with two natures.


And yet it is part of the story of Redemption that one of the divine persons (the Second) took on human nature in order to redeem human beings.


Here is where Aquinas’ argument takes a surprising turn: he points out that once a divine person chooses to take on MORE THAN ONE nature, there is no reason why that person should be limited to having merely TWO natures. There is, in principle, no reason why the divine person should not have the ability to take on three, four, or many natures, all united in an expanded version of what we refer to (in our poor human language) as the Hypostatic Union.


In view of the modern interest in life on other planets, this insight of Aquinas must be considered remarkable. For if there are rational creatures on other planets, endowed with free will, then it is possible that sin exists on other planets. And if so, those fallen beings will require Redemption just as we humans did. Presumably, the Second Person of the Trinity (through whom all things were made, and for whom all things were made: Col. 1, 16) would be the one to effect the Redemption of those fallen beings also. And how would He do that: presumably by taking on their nature in addition to His Divine nature. His Person would remain single (the Second person of the Trinity), but he would perform his actions in that other world through the nature of the rational beings of that other world.


Using this insight of Aquinas, we Christians do not have to fear that “our God is too small” to accommodate the possibility of alien life. Instead, we can rejoice that it may not be only ourselves who can claim: “In Him we live and move and have our being” (Acts 1,28). Perhaps there is another race of beings who can rightfully make the same claim. Perhaps there are many such races.


To be sure, this race (or these races) may not live on any of the 100 planets which are known to today’s astronomers. But if such races exist, they must live on some planet somewhere. And someday, if God wills, we may be permitted to make contact with one of them. Won’t that be the day! On that day, if God wills it, among the people who rejoice will surely be the former professor from Paris (St. Thomas Aquinas) and the former professor from Cornell (Carl Sagan, R.I.P.).