I personally believe that everything that happens in our lives is predetermined. I don't necessarily connect it to any deity, but I think we are living in some sort of simulated world. What do you guys think?
I forget where I heard this analogy, but it's something like this:
If you push a ball down the ramp, if you somehow know every bit of matter that exists in the ball/ramp/surrounding area and what its exact state is, you know whether or not it will reach the end with 100% certainty. If you throw a basketball, and you somehow know all the air drag, speed of the ball, rotation of the ball, hoop location, everything like that, you know where the ball will go and whether or not it will go into the hoop.
If you know every proton, every neutron, every election, every wave of light, every sound, every bit of movement, everything, then you can predict every event in the universe provided they follow the ruleset of this universe (laws of physics, etc.)
Any closed operation when forced to follow certain rules will only be affected by what is inside the operation, aka the universe. This means everything that happens can be predicted based on the starting conditions of the universe.