I'm not sure I'm the person to be answering this, because I don't have a God to condemn. I'm assuming you mean to ask if anyone who is set in their faith be changed? I do not believe in God, but in coming to this site, I'm having revelations as to what "God" means to me. I am willing to condemn my faith that there is nothing more than biology. I am becoming spiritually fulfilled.
I think the problem is that Believers already have an answer. And when they have questions beyond that, they have a source to turn to. Non-believers are lost in the world, and choosing one arbitrary source over another is the hardest thing for us to do, especially the extremely logical.
I do wish they'd be more open-minded.
big - Swedish - onerous, arduous, difficult, tiring, requiring or using a lot of energy or strength
"presumably"... 3 seconds on Google, man. Do not presume anything.