God Can't Be (Dis)Proven
One of the most futile debates you can possibly have is about the existence of God. Unless the argument is purely philosophical, it is bound to end up going nowhere — because God can't be proven empirically.
To prove (or alternately, disprove) the existence of God empirically, the scientific method has to be followed. The first step, naturally, is proposing a hypothesis, i.e. God (does not) exist(s) — depending on whether you're arguing for or against theism, include or exclude the portions in parentheses.
At this very first stage, we run into problems. How do you define God? What definition of God do we use? I think the following definition would probably be acceptable to monotheists:
God is an omnipotent, omnipresent and omniscient being.
Our hypothesis thus becomes:
An omnipotent, omnipresent and omniscient being (does not) exist(s).Now, let me ask you... Just how on earth do you prove or disprove this hypothesis? If this being is omniscient — all-knowing — it will know we're looking for it. And if it is omnipotent — all-powerful — it can hide itself at will.
The result is that unless this being chooses to reveal itself to us, it is impossible to prove or disprove the hypothesis, since the subject of our experiments will be able to manipulate the evidence at will. Some creationists when confronted with radiocarbon dating argue that God put the dinosaur bones in the ground and artifically backdated them, but in reality we were created 10,000 years ago.
If such is the case, how do you empirically and scientifically prove or disprove God? You definitely can't disprove him, because of this manipulation of the evidence, if there is a God.
At the same time, you can't prove God's existence unless he comes out and issues a statement along the lines of "Hey guys, I'm God. See, I can prove it — I'll just turn this wine to water." Without such hard evidence, all the theists have left going for them is aphorisms like "Absence of evidence is not evidence of absence." (Intelligent design as a scientific theory is utter bunk — all the proofs of intelligent design are nothing more than critiques of evolutionary theory as it is currently understood, and don't in themselves prove that there is a higher being.)
But what does this failure to prove or disprove God actually bode? Does this mean religion or atheism is pointless, since we can't prove any hypotheses about God's existence or lack of it?
I don't think so. I think there is actually a subtle beauty in our inability to prove God's existence empirically. Being able to prove that God is real would actually be the real death blow for religion.
The point of religion is faith — to believe, not just accept. Being a Christian, I naturally will prefer Biblical authorities, but I'm sure followers of other religions will be able to find passages in their own holy book with similar meanings.
The Bible states "The fool saith in his heart, there is no God" — it does not say "saith in his mind" or "saith in his thoughts". If there is empirical evidence God exists, there is basically no point in believing — you are forced to believe God exists, not because you are convicted in your heart that he is real, but because the evidence is there and you can't run away from it.
Believing because you have to, and believing because you hold a conviction in your heart are two totally different things. As the Bible says, "Even the devils believe [God exists]". Their belief does not save them, because they do not hold a conviction in their heart about God — they just have no choice but to accept God exists.
The fact that God has not given us evidence of his existence is meant to affirm our free will, and to lend our faith a meaning. Hard atheist Richard Dawkins says that if after dying, he finds himself in front of God, he will tell Him, "Not enough evidence, God. Not enough evidence."
But the point of the evidence's absence is to give us a choice, and to make believing truly believing. That is something all people, theists and atheists, have to come to terms with. Trying to empirically prove that God exists, or to disprove his existence, beyond as some mental exercise, is a complete waste of time.