Faith in science is different from faith in religion. One is inherently more logical than the other, according to most scientific philosophy. However, one can not fully prove that God doesn't exist - that being said, one cannot prove Santa Claus doesn't exist, but we can induce with a high level of certainty (over 99%) that he isn't real.
Concerning God, one must support Agnosticism to be truly philosophical; however, there is also "Agnostic Atheism" - the belief that we cannot know whether God exist, but we can assume, with a high probability, that he doesn't.
While I am Agnostic Atheist, Isaac Asimov has a good arguement for Strong Atheism:
"I am an atheist, out and out. It took me a long time to say it. I've been an atheist for years and years, but somehow I felt it was intellectually unrespectable to say one was an atheist, because it assumed knowledge that one didn't have. Somehow it was better to say one was a humanist or an agnostic. I finally decided that I'm a creature of emotion as well as of reason. Emotionally I am an atheist. I don't have the evidence to prove that God doesn't exist, but I so strongly suspect he doesn't that I don't want to waste my time."