I am in no way a believer in any god or higher being, but I still believe in our lives being predetermined. I was trying to explain this to my friends but I had just dropped acid and only one of my friends was sober. Let us start: Our universe is governed by some governing force. We translate these forces into mathematical and verbal code that we use to measure the universe. We do not know all of these laws yet, obviously. Everyone can agree thus far, correct? Because our universe is governed by these forces, everything in the universe happened the way it did. Our galaxy, solar system, and planet formed when they did and where they did because they followed these rules. The emergence of life, in particular human life, happened because of these physical laws. Your birth was caused by your fathers semen and mothers ovum following these forces. The chemistry in your brain is run by these laws, and all of the stimulus you have received since you were an infant have altered you to be the way you are. I pretty much mean to say that there is no chance. There is no randomness associated with the universe, it is just such a huge amount of tiny factors, all of which are measurable and are governed by the laws of physics. If we knew a way to represent exactly the way the universe works mathematically, we would be able to tell the future, but I don't even think it is possible, and even if it were possible the processing power necessary to make anything useful out of that information will probably never exist or at least not for a very long time.