"What are the best arguments against alien life elsewhere? My son's and I had an interesting discussion about the vastness of the universe and the probability of alien life. I began to explain the Fine Tuning Argument, Goldilocks Zone, and such. Then one of them asked me how we know that other lifeforms would require the same parameters. Examples of "life" under extreme conditions here on earth were mentioned."
Recently, I found the above question on a Facebook group. With the possibility of alien life being an increasingly hot topic, I thought it would be a good question to answer here on Bible Brain, too.
For centuries, we have known that life is a very delicate thing, and as time goes on, we learn just how delicate. Where it was once thought that all a planet needed to be suitable for life is for it to have water, we now know there are many essential parameters which, if they are even slightly off course, will prevent even existing life from survival. This, of course, puts quite the damper on the idea that life could have evolved even here, much less elsewhere. It is such an extreme coincidence that the Earth itself is suitable for life that we can pretty much rule out coincidence full stop. Our planet, as the Bible says, was intentionally formed to be inhabited (Isaiah 45:18). By contrast, the planets elsewhere, clearly, are not supposed to sustain life.
But others have suggested that while the Earth is clearly fine tuned for Earth life, perhaps other life forms might exist with different requirements. After all, even here on Earth, there are things called extremophiles; amazing organisms, like the famous tardigrade, that are able to survive where most other organisms would be instantly killed. The aforementioned tardigrade has even been noted to survive in space.
If the tardigrade can survive in space, it's only natural for those who do not recognise its Creator to ask, could something similar maybe survive elsewhere? It is worth noting that although a tardigrade can survive in space, it does not actually thrive there. It survives by, in effect, switching itself off. Everything from its metabolism, right down to its respiratory functions, shut down. In other words, if you put it in space and leave it there forever, it may as well be dead. It needs the conditions of the Earth to actually live.
But more importantly, while we have seen and studied the tardigrade, and other extremophiles on the Earth, all of which need conditions found here on Earth to live a full life, we have never observed any life which, hypothetically, may exist out in space. However, as it stands, I'm actually not opposed to the possibility. As clear as the Bible makes it that the Earth is designed to be the center of all life in the universe, if God can make planets out of gas, I see no reason to freak out if it turns out He's placed a Pompeii worm on Pluto. If some sort of tree emerged on the face of the moon, I wouldn't even blink. Not that I expect it to happen, it just wouldn't affect my faith if it happened.
By contrast, the Bible tells us quite clearly that there actually is life that does not require the conditions found here on Earth to survive. To begin with, God Himself. When there was no Earth to sustain life, there was God. When there was no sun to potentially sustain a planet in its Goldilocks zone, there was God. When there was no space to accommodate physical reality, there was God. Even when there was no time, God existed, and nothing but God could create or sustain life. Thus, it is true, there is life with different requirements than the life here on Earth.
Thus, while we may speculate about the "what ifs" regarding life elsewhere - what if life forms exist that do not require the parameters it needs here on Earth - we may ask, well what if there are spiritual beings, who have no physical requirements at all? What if Satan can lay his head on the moon? What if Gabriel can chill out next to the Mars Rover? And of course, what if there really is a God so powerful, He can create the heavens, the Earth, and all that is in them, in 6 days? If we're going to play the "what if" game, God and aliens are always on equal footing.
Except they're not.
Much like with the extremophiles here on Earth, there is less guesswork involved when it comes to God. We can start off with the classic Cosmological argument. It is impossible for there to be an infinite regress of time or cause. There must be a first, uncaused cause in a first moment of time with nothing before it. Otherwise, we could not exist. You cannot cross an infinite, and thus, we must have crossed a finite. God fits the bill perfectly; there was never a time when He did not exist. If He is the first cause, with His first creative act being the very beginning of time, then not only can we exist, but we should exist. And we do.
But you don't need mathematical arguments like that, and indeed they are actually insufficient. Proving that a god must exist does not show who that god is. It's like pointing to a house and saying "that couldn't have built itself, therefore I did it". Well, it's true, my house needs a builder, but that doesn't mean that builder is me.
So how do I find out who built my house? The best scenario would, of course, be to watch the builder/s in the process. But my house is older than me. I wasn't there. So perhaps I could at least talk to the builder/s? Well, no, I don't even know if one person who worked on this house is still alive. But there are official records I can look into. These are ways I can find out who built my house, and when, and maybe even a few details on how.
We were not there at the foundations of the world. It has been 6,000 years since Adam took his first breath, and even he was the last thing God directly created. Not that he left any written records, as far as we know. But we actually do have a rather extensive record of the history of this planet.
In spite of this extensive record, most gods have been conspicuously absent. There is one exception. One God who actually walked the Earth in various forms. One God who genuinely empowered His servants. One God who genuinely performed miracles. One God who was witnessed by whole communities, in plain sight. One God who foretold futures we could never have speculated.
But even this pales in comparison to His greatest miracle. See, God is triune. That is, although there is only one of Him, He consists of 3 separate persons; The Father, the Son, and the Holy Spirit. 2,000 years ago, the Son became incarnate in human flesh, entering our world through the womb of a virgin. His miraculous ministry is preserved, in its purest form, in the New Testament, a collection of historical records by eyewitnesses and contemporaries, but it does not stop there. Even Jesus' enemies saw fit to record His deeds, though of course in their own nefarious ways. Though they attributed His works to Satan, in so doing, they confessed that His ministry was, in fact, miraculous.
In the modern day, even secular historians admit that the death of Jesus by crucifixion is one of the most certain facts of history. However, using similar logic, we can say the same about His resurrection. Eyewitnesses to this particular event are not only common, but zealous. Many people confessed to having seen the risen Lord, but they were actually willing to lay down their very lives for this claim. Many of them even did.
Ultimately, therefore, we can speculate about hypothetical life forms that do not need the conditions found here on Earth, but until they actually show up, they remain speculative. By contrast, we, as a species, have seen God. This is a far more fruitful discussion to have, as when all is said and done, there is nothing out there in the universe that can actually affect your eternal soul. A time may come when we find life on other planets, or even when we find scientific ways to extend our own lives here on this planet, but none of that will ever stop the one thing this universe seems Hell-bent on delivering to us: Death.
Death is inevitable. We live on a planet that can delay it for a time, but nothing in this universe will do more than slow death down. As the word of God tells us, "...it is appointed for men to die once, but after this the judgment" (Hebrews 9:27). How will that judgement go for us?
There is both good news here, and very bad news. The bad news is, it is all too possible for this judgement to go poorly. Every thought, word, and deed will be called into account, and unfortunately, the only human being who ever walked this Earth without sin is Jesus. You and I could not stand in His presence. However, "...He made Him who knew no sin to be sin for us, that we might become the righteousness of God in Him." (2 Corinthians 5:21). The sin that brought us death has been paid for, enabling us to stand before God as if we never committed it. The sole condition of this is faith. Those who confess Jesus as Lord, and believe in our hearts God raised Him from the dead, will receive eternal life on the New Earth. Everyone else, sadly, will be consigned to a harsher environment than any extremophile; an eternity in Hellfire.