Stories about unexplained aerial phenomena (or UAP—which is what we’re now supposed to call UFOs) used to be reserved for the more garish or sensationalist parts of the internet or the tabloids lining the bottom rung of magazine racks. Not so today, when stories pointing to the evidence for extraterrestrial life are now turning up in every major news outlet.

Prominent, as ever, is a headline that won’t go away: that the US government recovered crashed spacecraft with “nonhuman biologics.” There’s even a newly released book detailing, as the headline of a recent Time article suggests, “The Government’s Search for Aliens and Why They Probably Exist.”

Perhaps now is an ideal time for Christians to start asking some serious what-if questions, like “What if the front page of tomorrow’s newspaper carries news of evidence of life on another planet?” This question has led me into some of the most fascinating theological territory I’ve ever considered—some of which I explore in my recent book, Astrobiology and Christian Doctrine: Exploring the Implications of Life in the Universe.

I was also one of two dozen theologians invited to participate in the NASA-funded research project on the societal implications of astrobiology at Princeton’s Center of Theological Inquiry. And in my research, I was surprised to discover that Christian thinkers have been pondering life beyond Earth for a long time. Why? One reason is that the Christian worldview has a unique set of prior assumptions that may make us more willing (not less willing, as some might assume) to believe in the likelihood of extraterrestrial life.

Let’s look, for example, at the reactions to one UAP in particular, which leading scientists seem most excited about. ‘Oumuamua (Hawaiian for “a messenger from afar arriving first”) entered our solar system and passed quite close to the sun (and not that far from Earth) on September 9, 2017, traveling at almost 200,000 miles per hour. This was the first “interstellar object” observed in our solar system—that is, an object that has traveled between stars, in contrast with a comet, for instance, which is bound by the sway of our sun’s gravity.

That’s notable enough, but ‘Oumuamua had some other unusual properties. We can’t be exactly sure about its shape, but it seems to have been either an oddly long and thin object, like a stretched cigar, or perhaps a disk (or even a saucer, as familiar from so many science-fiction films). It also took an unusual trajectory when it got near the sun.

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What are we to make of this? Might those unusual properties suggest that it wasn’t any old object but rather an artifact from another civilization?

For Harvard astrophysicist Avi Loeb, ‘Oumuamua is so odd that seeing it as an alien artifact makes the most sense. On the other hand, the philosopher Christopher Cowie has argued that even if there is other life in the galaxy, extraterrestrial artifacts would be too rare to be a plausible explanation for ‘Oumuamua.

What distinguishes Loeb and his critics is not whether ‘Oumuamua is odd—on that they agree—but whether that counts as evidence of other civilizations. Loeb’s critics think such civilizations are so unlikely that it makes better sense to say that while it’s odd for a natural object, it’s natural nonetheless. In contrast, Loeb thinks that such civilizations are probably widespread, so it’s more likely that ‘Oumuamua is alien workmanship than some freakish natural object.

Astrophysicist Charles H. Lineweaver examined ‘Oumuamua using Bayes’ theorem: what makes for a plausible explanation for evidence depends on our prior assumptions. That is, whether it’s credible to believe this was an alien spacecraft relies on what else we take for granted—such as how likely we think the existence of extraterrestrial civilizations might be.

The progenitor of Bayesian logic is Thomas Bayes, an English Presbyterian minister from the 1700s whose ground-breaking work was likely provoked by the attack on miracles by philosopher David Hume (in An Enquiry Concerning Human Understanding). Hume argued that we shouldn’t accept stories about miracles since—as he saw it—there will always be a more likely, nonmiraculous explanation for any extraordinary event. Our interpretation depends on our assumptions, and his assumptions did not stretch far in the direction of God.

And while we don’t know for sure whether Bayes was, in fact, inspired by Hume’s book, his friend Richard Price made this connection. Price was a doctor of divinity and brought Bayes’ work on statistics to public attention following his death. His treatise against Hume’s skeptical take on miracles (On the Importance of Christianity, the Nature of Historical Evidence, and Miracles) followed a few years later. Bayes realised that we interpret events as likely or unlikely depending on our presuppositions, and Price applied that logic to miracles—in the very first application of “Bayesian” thinking, as far as we know.

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As a confirmed agnostic, Hume was skeptical about God. So, he considered a miraculous explanation of an unexpected event to be less likely than some natural explanation, even if he didn’t know what that might be. But a Christian, like Bayes or Price, comes at the same story from a different perspective. If you believe in God and in Jesus as God incarnate, it doesn’t seem at all far-fetched to suppose that Christ could turn water into wine or calm a storm.

Or, in this case, we may be more likely to believe in the possibility of life beyond Earth.

Turning from the 18th century to the 20th, there’s a common (but wrong) assumption that religions are unimaginative compared to science and that they need scientific discoveries to provoke them into thinking about life beyond Earth. Carl Sagan, a renowned astronomer, leveled this very charge when he asked:

How is it that hardly any major religion has looked at science and concluded, “This is better than we thought! The Universe is much bigger than our prophets said, grander, more subtle, more elegant. God must be even greater than we dreamed”? Instead they say, “No, no, no! My god is a little god, and I want him to stay that way.” A religion, old or new, that stressed the magnificence of the Universe as revealed by modern science might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths.

Yet Christian theologians have been thinking about life beyond Earth continuously since the middle of the 15th century (and Jewish and Islamic theologians for even longer). If there’s anything frustrating about how Christian sources address this topic, it’s that they don’t tend to be very long—the author mentions the prospect cheerfully and then moves on. It seems these thinkers just weren’t worried enough to write a great deal on the subject.

In the 15th century, we have a Franciscan friar, Guillaume de Vaurouillon, and Nicholas of Cusa, perhaps the greatest theologian of his age. In the 17th, there’s the Dominican Tommaso Campanella (writing in defense of Galileo). We could add English Puritan theologian Richard Baxter and Anglican John Ray, who wrote of the possibility of other solar systems with planets that were “in all likelihood furnished with as great variety of corporeal creatures, animate and inanimate, as the earth is, and all as different in nature as they are in place from the terrestrial, and from each other.”

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Nineteenth-century preacher Charles Spurgeon spoke of all creation as a “grand orchestra” with “the inhabitants of the divers worlds, which are perhaps countless in multitude, taking their places in the one harmonious song.” He believed there “may be tens of thousands of races of creatures all subject to him, and governed by the same law of immutable right and justice.”

In the 20th century, C. S. Lewis was fascinated with outer space, writing an essay (“Religion and Rocketry”) and three novels (the Cosmic Trilogy) on the topic. Lewis did not believe the discovery of life on other planets would challenge Christianity, although it would certainly raise some intriguing theological questions for us to consider.

One prominent writer, John Wilkins (Bishop of Chester and a founder of the Royal Society, England’s most prestigious scientific organization), thought he had evidence of life on the moon, but most theologians were speculating without evidence. That said, it’s striking how many theologians believed with strong conviction that there is life beyond Earth on theological grounds—those who took this as a certainty, not just a possibility.

As before, what you think is plausible depends on your prior assumptions. Many Christian theologians have operated with the assumption that God would create habitable places only so that they could be inhabited. And so, far from rejecting the idea that the universe may contain other life, we find theologians arguing that life beyond Earth is widespread. Indeed, they assumed that there will be life pretty much everywhere it could possibly survive.

If your assumption is that life is what matters, especially to God—and therefore that habitability is for the sake of habitation—you’ll find it implausible for habitable places to remain bare. Historically, then, Christian theologians have often likely overestimated how m uch life there might be in the universe. That followed plausibly from the assumption that God populates places and that places are valuable if they host living things.

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I’m very open to the universe being full of life, but I’d say that some of the assumptions mentioned in the previous paragraph are faulty. There is a splendor in all sorts of different kinds of places in the universe, all bearing witness to the glory of God in their own way, whether they are inhabited or not.

The 20th-century French Roman Catholic theologian Jean Guitton wrote that a vast universe, uninhabited other than Earth, was implausible because that would essentially make “the pedestal too big for the sculpture.” In other words, the universe would be like a picture frame so big that it overwhelmed the painting at its center.

I think that’s wrong twice over. First, even if the universe contained life only on Earth, an unimaginably large universe would not be too splendid a setting, frame, or pedestal for the glory of life on Earth—especially for human life, with its self-awareness and relation to God.

But second, is it even helpful to think about the rest of the universe as merely the stage for life? The universe has a glory and dignity of its own that isn’t to be judged merely in relation to us. After all, we’re not the only creatures with a vocation to praise God; the heavens do too (Ps. 148:3–6). The heavens themselves are alien and inscrutable—so much so that God brings them up when he puts Job in his place for questioning his sovereignty (Job 38:31–33).

When it comes to the place and prevalence of life in the universe, I’ll let the science inform me, as and when the data comes in. I won’t be perturbed whether we find a lot or none at all.

That said, I’ll be surprised if Earth’s is the only life. After all, we didn’t know until the end of the 20th century whether there are planets around other stars—and it turns out they’re everywhere. Finding evidence of extraterrestrial life might be quite a feat. Yet our ability to detect signs of life around other planets has taken a massive leap forward with the 2021 launch of the James Webb Space Telescope: It senses infrared light, which is ideal for measuring the balance of gases in the atmosphere of other planets and thus ascertaining some of the telltale signs of life.

Christian theologians have thought a good deal about what makes something alive and what counts as a living thing. For instance, angelic beings are an example of life beyond Earth mentioned in the Bible and featured in the Christian imagination—however different they might be from other biological life.

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Does it matter that there’s no mention of extraterrestrial life in the universe in the Bible? I wouldn’t say so, especially as we consider what the Scriptures are for and what they’re not for.

In the Bible, God speaks to us in a human way. Does that make our understanding of God so human-shaped that other creatures wouldn’t think about God like we do? Plenty of theologians, such as Calvin, talked about divine “accommodation”—the fact that God speaks to creatures in a way they can understand. Knowledge of God and revelation from God would surely be “accommodated” differently for different creatures so that they could understand it, but it would be the same God who is revealed and known.

Then there’s the idea that human beings are made in the image of God. Is this premise undermined if there are other creatures that can also know and love and be made friends of God? I don’t think so. We would be no less wonderfully created and no less loved by God just because other things are also loved and wonderful—and probably wonderful in a different way from us. The more the merrier, I should think.

But what of sin and salvation? If there’s other sentient life, is a fall inevitable? And what about the Incarnation and redemption? Could Christ’s death and resurrection redeem the whole cosmos? Undoubtably, but would God limit himself to one Incarnation? That’s perhaps the most hotly contested question in the field. As Aaron Earls pointed out for CT, even C. S. Lewis thought it was at least worth considering the possibility that Jesus could have “been incarnate in other worlds than earth and so saved other races than ours.”

As for me, I believe one Incarnation is “enough,” but who says God must do what’s minimally necessary? In Jesus, we see God face to face as a human being. But I could see the beauty in other creatures also knowing God in their own flesh and blood.

In the early 20th century, English poet Alice Meynell wrote that only we know our story and that what God has done elsewhere remains elsewhere:

No planet knows that this
Our wayside planet, carrying land and wave,
Love and life multiplied, and pain and bliss,
Bears, as chief treasure, one forsaken grave.

Nor, in our little day,
May His devices with the heavens be guessed,
His pilgrimage to thread the Milky Way
Or His bestowals there be manifest.

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But she ended that poem, entitled “Christ in the Universe,” with the tantalizing idea that we can look forward to knowing the rest of the story of the cosmos in the life of the world to come:

O, be prepared, my soul!
To read the inconceivable, to scan
The myriad forms of God those stars unroll
When, in our turn, we show to them a Man.

Ultimately, whatever lies beyond Earth, of this we can be sure: God will be gracious, and God will do something glorious.

Andrew Davison is the author of Astrobiology and Christian Doctrine: Exploring the Implications of Life in the Universe. He is grateful to Cat Gillen at Durham University for discussing ‘Oumuamua from a Bayesian point of view.

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