Martin Wagner from The Atheist Experience Blog takes on the argument that God is unknowable therefore his existance can not be proven scientifically.
This is an argument that I get every now and then myself. And, boy howdy, do I have a problem with it. When I was a practicing fundamentalist, I would have argued against that point. I believed that God was knowable because I thought that I had a real relationship with him. Funny thing is that a few of the people who argued that way, would also say that they have a relationship with God. So, how do you have a father and son type relationship with something you can never know. Makes no sense to me.
A being that can never be known may as well be non-existent. I would advise my christian friends and family to never argue that God is something that looks a lot like non-existence. Such as being outside of time and space or not of the universe. Besides, from what I know of fundamentalists, most of them would say that God is real and that it can be proven. So, a fundie using this argument makes very little sense and it looks like a very desperate move from my point of view.
I agree with Martin. This is pretty much the most desperate form any apologetics can take.