This is an argument that always kills me. If one subscribes to even the most basic ideas of logic, it's utterly senseless. And yet, it's rolled out constantly, held up to the sky in triumph, and declared to the Heavens that God must be real because we don't know for absolute certain what happened before the first millionth of a second after the Big Bang.
So what? I like to use germ theory at this point. There was a time, not very long ago at all, when we had no idea where sickness came from. There were a lot of people who thought that plagues and epidemics were the work of God, wreaking havoc on a sinful people. Had there been atheists at the time who were as vocal as we are now, they likely would have been saying things like "No, it's not God; there is no God. It must be something else". And they would have been right. Just because we did not, at that time, know why people got sick is in no way proof of God.
The same holds true today. We don't really know how the universe came into being, though we have some pretty good ideas. We don't know 100% how the first life came into being, but we've got some really good theories for that one; I would add the caveat that it's possible that it's just that I don't know how abiogenesis works, and that there are people who do. This would not surprise me.
Complete aside: It upsets me a tiny bit that my spellchecker doesn't know the word abiogenesis.
It's ridiculous to think that the gaps that remain in our scientific knowledge somehow prove God. I wonder sometimes, if tomorrow a scientist was somehow able to prove, absolutely, 100% beyond a doubt, that abiogenesis occurs... would these people then be willing to abandon their religious beliefs? I doubt it. They'd either move the goalposts - sure, you proved that, but what about the Big Bang, huh?! - or choose to ignore the evidence altogether.
That's really the worst part of it, for me. That second point there is already happening. I'm thinking, here, of evolution. It's been proven. Shown. Time and time again, with evidence coming in from well over a dozen different scientific fields... and it all gets ignored. Evolution deniers will ask me questions, thinking them impossible to answer. "Show me the transition between a hippo and an elephant, then!", they scream, tiny beads of froth forming at the sides of their mouths. And when I calmly reply that I can, in fact, explain that to them if they're willing to allow themselves to be educated, I'm routinely ignored, or informed that no, they don't need any explanation. They know what evolution is, and they think it's just stupid. All this while yelling things about evolution that have no basis in the theory itself.
I went off on a bit of a rant, there. The subject does get me really riled up. I have no problem with one keeping one's faith, but don't preach that science has it all wrong. That's lunacy of the highest degree.
Rant aside, the point remains the same. Your ignorance, my ignorance, or the ignorance of the entire human race, does not prove a god. Nor does it imply that we'll never be able to end that ignorance. That's what we scientists are trying to do; increase our knowledge. That's the point. Those that are trying to hold us back from that, who want to retard our progress as a species, are my enemies. And I will fight them. Red, in tooth and claw.