The big bang created every particle in existance. The movement of these particles was dictated by the big bang. They moved and collided with one-another based on their original vectors, and created new vectors and new particles. On the large scale, galaxies were formed, and they interacted with one-another based on the physical laws set forth. Following the big bang, more and more variables were created (variables meaning a particle, or molecule or solar system...anything in existance), but they can all be traced back to the big bang by looking at the preceding variable, and the one before it, and before it, etc. You can follow the movement of matter and energy all the way down to the creation of earth and the dawn of human civilization. At this point there are billions of different variables in existance, earth and everything on it being a few of those, and all of those billions of variables are colliding to make new ones. To put this into context: we are here as a result of our parents, their parents before them etc. We have the talents we do, due to our genetic makeup, places we have been, things we have done etc. These were all due to preceding variables. We think the thoughts we do, because of a combined number of variables preceding the thoughts. Think about it like nuclear fission: one particle goes to make 2 more. Each of those make 2 more etc. but each one can be traced back to the original particle by looking at the previous fission. Does this not seem to dictate that all events have unfolded in a mathematical way, defined by the big bang? Does this not also seem to dictate that the future must follow this same complex mathematical equation? Therefore, are all things not predetermined?