My siblings are agnostic, should I try discussing atheism with them?

[Phosphorescent Panties]

Or just leave it alone? My brother won't admit anything but he says the same things I've heard atheists say and whenever I ask him if he's an atheist, he uses vague phrases like "well, you know" and "am I?". My sister started becoming a hardcore christian, but then she finally read the bible. She slowly started noticing things and then just said she didn't believe in jesus. But then yesterday she told me that she doesn't know or care what's out there and that's she's definitely not with any religion or god (yay!). So my question is, should I try talking to them or leave well enough alone?

It's hard to discuss anything with people who are not willing to be wrong. If you try to convince someone that they're wrong about their understanding of the world, they'll probably try to shut you down, give you a lot of questions that are logical fallacies, etc. Unfortunately, people have to be willing to open their minds and be wrong and learn. That's what I like to think of as having a scientific mind. Science is self scrutinizing and changes it's ideas to suite the evidence it finds. If someone does not have this state of mind, there's nothing you can do to persuade them. People who are truly "believers" will not try to defend their faith logically, they know they can't win, which is why they're religious.