Hi Marisa,
I've pondered the same thing, and agree that nothing is concrete. When it comes to belief in what will happen to us when we pass, the answer is really in the facts you can accept, the things you can believe. Having said that, seems kind of ironic that those who go against the belief system ultimately have one of their own, don'tcha think? Personally, I'm Christian so pondering this subject is all that much worse, well...according to my peers it is. But I don't believe so. God judges and provides me with what I need to know, not them.
According to the scientific theory, we just cease to be...and our death provides sustenance for the next generation. So when the time comes, you won't care about the chance you have because you simply won't be. Scientifically this makes since, since once we pass our body loses it's "boss", so-to-speak...and the cells eventually cease to function and wither out. Circle of life kind of deal, we take from the earth, then give back in our death for the next generation to reap and begin the cycle again.
The Christian belief varies, depending on the vocation, and ultimately your teacher/preacher. I find the most peace with this belief because it provides my life with a purpose that transcends this life, and myself. It helps in the belief that the things that happen to me, the things that happen to others, all have a purpose and from that the next step can be much easier to find. I guess in essence, the idea is that everything you do is for a reason. I find the most hope in this. I need to know that what I do isn't just "doing it to do it". I find a very big gaping hole in me when I think everything I do is pointless, just an action with a reaction kind of deal. There are a great number of other things involved, but I'll leave it at the general idea for now.
And the chaos theory isn't really a belief system for life/death. Although it can relate because it can have an outcome that is life or death, the general consensus with the chaos theory, is that for every action, there is a reaction.
I love philosophy and the sciences! Ponder and ask whatever you want, and I'll debate with you the ideas I've found with each...well, the one's I know. Though ideas aren't always concrete, each does have their own logical process which helps with the conclusion that you come to.
Welcome to the board!
Cheers!