This blog is fast becoming a random series of unconnected thoughts, rather than structured series on one issue, then another unconnected issue. However, never mind!
Someone, normally thought (wrongly) to be G.K. Chesterton, once wrote: "When people stop believing in God, they don’t believe in nothing — they believe in anything."
So people believe in all sorts nowadays - in the power of crystals, in ghosts, in homoeopathy, in astrology, in all sorts of stuff. Perhaps the most widespread of these is sentient extra-terrestrial life. Hollywood and television have helped to spread this belief - Star Trek and other sci-fi.
Here are some ramblings of mine on aliens.
Belief in aliens is like belief in God
There are many reasons why. The first is that we can only guess as to their existence from what we know and we have no idea, if we start from our reason alone, what God or aliens are like. We have no idea how many planets there are, how many can support life, or even the chance that on a given planet identical to earth, what the odds of intelligent life are. We have reasoned guesses, which could be right or not.
There's the low odds of the opposite being the case, given the data and assumptions we have. This isn't proof (yet many people erroneously assert it as proof). However many of those who support 'Intelligent Design' (I'm not counting young-earth creationism in this - their arguments are different) and many of those who support 'Intelligent Extra-terrestrial Life' do use this. You get stuff (and I've been guilty of both in the past) like "The odds of us being here by chance are so low that we have to be designed" and "There's so many planets that there has to be aliens". Oddly the two collide - one is taking about the low chance of life existing, the other is talking about how, despite, the low chance of life existing, there are lots of rolls of the dice, so to speak.
Thirdly, there's the also awful 'proof by longing' - the "I just can't believe we are alone" type-line.
Forthly, and back into the realms of good arguments for both - the existence of God and the existence of intelligent alien life can only be proven if there is contact between the two - God and the aliens need to speak to us, and better yet, meet us. The God of the Bible is a speaking God, who came and lived with us. The only proof we can have of aliens is if they do the same - speak to us and meet with us.
Does believe in aliens disprove Christianity?
No. However the lots of planets, therefore lots of life-forms argument undermines some of the bad arguments for God. Also there's the problem that aliens perform the psychological functions of God that people may want - the lack of 'loneliness' (there's over 7 billion other humans on earth - so I don't see how we are alone - we have each other) and so on. This leads to people not wanting God, as the psychological crutch they want him for is filled.
There is the problem about the specialness of man - how do we get around that? C S Lewis' two famous fiction series take different approaches - in the Cosmic Trilogy, the aliens aren't fallen - they don't even have a word for sin; they don't need a redeemer. Secondly, the Narnian books have sentient talking animals, and Aslan comes and dies as a sentient talking animal to redeem them from their curse. Both are possibilities. A third option exists - aliens could be fallen and un-redeemed - many angels fell but God hasn't come and died as an angel, redeeming them. However there are also unfallen angels, so that's kind of a special case. There's also no reason to assume that man isn't special, despite similar creatures - we don't deserve it, but that's grace for you.
Belief in aliens is symptomatic of man's longing for the unknown - it's a religion. What's ironic is that many 'new' atheists will happily believe in the existence of aliens, yet slam unicorns, dragons, etc - those aliens could be unicorns, dragons, or all sorts of things - we don't know. Belief in aliens is belief in future evidence - at the moment, we can't honestly say if there is - the data could go either way with the probability of aliens (and that doesn't say yes or no to their existence). We have to wait for contact from them, to know that intelligent life exists elsewhere in the universe.
Also odd is that the 'new' atheists slam those who believe in God for believing in God, yet happily believe in aliens. After all, the way of proving if God exists is the same as proving aliens exist - have they spoken? have they visited? The best way to do this is looking at testimonies from people who claim it and to look in history to see if God/aliens have visited. I am certain that God has spoken and has visited, however I do not think that aliens have done either, due to the lack of evidence.