I think it's belief systemn because of the way I hear it defended sometimes around here. Also in some programs I hear atheists talk bout Nature in almost glowing terms, like it was their God or somethin. I really see no difference between atheists and religious beliefs. I think it's the same shit, different theory.
The big difference here is that speaking of Nature like that is based on evidence seen in the world around us. Many athiests I know are athiests in part due to the fact that there is no evidence of god. They base their beliefs on scientific facts that can be proven, not on a religious book that requires faith. That's not a put down, it's just a totally different path.
Faith and science are diametrically opposed, one is belief in only what we can see and the other is belief in something specifically because we can't see it.