The possibility of the existence of extraterrestrial life poses a problem for Christians who hold to Trinitarianism. Central to this mainstream of Christian belief is that God exists eternally in three Persons who partake of the same Being. Furthermore, the second of these three Persons became a human being, lived and taught among people nearly 2000 years ago, and then was crucified by the Romans with the encouragement of Jewish leaders, only to rise again a few days later and appear to his followers for several weeks before ascending into heaven. The core belief in the Incarnation as thus described does not work if there are or have been civilizations on other worlds in the universe.
Hinduism holds that many avatars of the multitudes of gods have appeared throughout time in the forms of humans or animals. From this perspective, the possibility of sentient life on other planets is no threat whatsoever to the faith. In Christianity, though, Trinitarianism in general and Incarnation in particular are undermined if indeed other intelligent species exist aside from humans. The particularity of the Incarnation centered on Jesus of Nazareth finds its roots various passages of the New Testament, and perhaps most notably in the Gospel of John, chapter 1, verse 1:
In the beginning was the Word, and the Word was with God, and the Word was God.
That passages goes on to explain how ‘the Word’ became flesh and dwelt among us, and makes it abundantly clear that it was in Jesus of Nazareth that this Word took on human form. Although it is often said that the Trinity is nowhere mentioned by name in the Bible, the truth is a bit more complicated. The sum of the various verses on the nature of God in the New Testament certainly point to something like Trinitarianism, with the Father, Son, and Holy Spirit distinct from one another and yet the very same. Not tritheism nor a multi-headed hydra, but something far more subtle and challenging to understand.
Throughout history countless people have questioned and denied the doctrines of Trinity and Incarnation, and have been persecuted and even put to death for finding it difficult to grasp and unlikely. As an aside, it is interesting to me how much this omnipotent god has to be defended, to the point of torture and bloodshed, by his adherents. One would think that such a being would be capable of defending himself. But, I digress.
Some through history have thought about the question of Christianity and extraterrestrial life, and none have created what looks to me like a satisfying answer that maintains traditional Trinitarian beliefs. For example, the Mormon prophet Joseph Smith Jr generated a revelation purporting to affirm the existence of other inhabited worlds, all created and governed by the one god of Christianity. In the largest branch of the Latter Day Saint movement based out of Utah this has evolved into a many worlds belief wherein pious Mormon men and women can become gods and goddesses (although the latter are rarely mentioned and the goddess(es) of this world is never worshipped), and in the significantly smaller but more progressive Community of Christ branch based out of Independence, Missouri the revelation is maintained but does not form a core doctrine of the church. In neither case is the likelihood that alien life will not resemble us handled in any meaningful way.
In case you’re curious, you can read Joseph Smith Jr’s ‘revelation’ on this matter either here or here.
In ancient times people such as travelers and merchants who visited foreign lands often noticed that the gods were different. They could believe those gods were their gods with different names, those gods were real but not their gods, those gods were fakes, or they could start to wonder if any gods exist at all. This encounter with other cultures could at times be quite disruptive for a person’s beliefs. How much more so would it be difficult for conservative and even many progressive Christians were we to make contact? The particularity of the Incarnation in Jesus of Nazareth would not survive the in the face of sentient extraterrestrial life, because there could not reasonably be multiple avatars of the Son of God, meaning multiple bodies, without doing violence to the biblical and creedal underpinnings of this belief.
Amusingly, some fundamentalists actually believe that UFOs as reported by anal-probed drunks alone in fields are real, but in fact are demons sent by Satan to mislead people. As ridiculous as it sounds, this is their way of attempting to deal with a world far larger and more complex than any of their predecessors ever imagined. If the Universe is vast, the Earth deeply ancient, and alien civilizations exist, then the form of Christianity that has been considered ‘orthodox’ for centuries is doomed.
Of course, Christianity will survive in some form, no matter what. Though their numbers might dwindle, Christians who want to hang on to faith will reinterpret in a number of ways to accommodate the new reality. For some this will be treating it more as a life ethic, others will focus on rituals and traditions, and still others will reinterpret everything as metaphorical. This is already happening among the array of shrinking mainline Protestant denominations, where their clergy hold to beliefs edging closer to atheism, or else whose theology is increasingly abstract.
As a Unitarian Universalist, that sounds like an awful lot of work to me. I’d rather just learn new things, broaden my horizons, and seek to understand whatever comes my way. If first contact were made this week, the beliefs of most of my fellow parishioners would not be deeply shaken or require radical reinterpretation. The Christians among us tend to see Jesus as a great teacher, though there may be some Arians (whether they know they are or not) in our midst who hold to some idea of Jesus being the adopted/exalted son of God. In any event, I’m pretty sure we’d all be fine and continue congregating each week…unless of course the aliens turn out to be hostile and attempt to exterminate us.
Whatever the case may be, it’s unlikely there will be a Zoidberg Jesus cult amidst our visitors/conquerors that’s agreeable to ‘orthodox’ Christian theology, and vice versa.