Well, on the paper I'm Christian, but in fact I really am not religious.
I have this one theory though, that destiny exists. But don't read any further if you're not interested in a childish man's view on the world.
Spoiler for Destiny exists because...:
...everything that exists is based on math. Everything is calculatabe. Take two balls and throw 'em at each other. Although it's somewhat complex, you can exactly calculate where they are going to land and where they are going to stand still. Everything is calculatable, even our own behaviour and way of thinking, because a man's personality is basicaly nothing more than electric signals in his brain. If we understood the way our brain works better, actions and behaviour would be calculatable as well. Yes, humans are programmed machines of organic material. We may be under the impression that we have the power to choose our actions, but we actually don't.
If what I wrote above is right, and I'm failable at that, because I am not a scientist in any way, but if what I wrote is right then...
...theoratically one should be able to precisely predict the future, if he knew the exact possition of every atom in the universe at a time, and how they react to eacher other.
That's why everything is predetermined, and why destiny exists, imo.
Omg, I can't believe I just wrote that down.