This thread kicks ass.
I'll play the devil's advocate, so we can keep this conversation going.
First, how is science any different than religion? When you boil everything down, how can you be sure about anything at all, ever? With science, they offer "facts" and "proof" but those facts and proof are based on perception, and on top of that, are based in a system founded on fallible theory. Theory is just that, and the cool thing about science is that it has this premise of "discovery" wherein if something doesn't agree with the "laws" that are in affect, through "discovery" (a fancy way of saying labeling) they come up with a new definition and thus a new "law of nature" is made.
Second, right now, you can't even be sure you are alive, or awake, in a coma, or dreaming. You believe you are. You even develop systems of proof to reinforce that you are. But how can you ever be sure? If you can't be sure you exist, how can you ponder on the infinite space of the Universe?
That's all for now, I have TONS more, just wetting the pallette...
I live for this kind of debate...