In science, we talk about how everything is a chain of reactions. A rock passes by our planet and has its trajectory altered by the reaction with our planet. One chemical reacts with another in our brain, resulting in a chain of events. One could literally begin at the BB and follow a long, perhaps infinite, chain of reactions which brings us to the point where I put the full-stop on the end of this sentence. Is what happens in our thinking, acting and reacting, nothing more than part of the action/reaction chain of events, where even the choices we make are determined by mathematical principles of chemistry and physics, if we had the depth of knowledge to plot every tiny spark, every miniscule chemical and physical event, leading to the illusion of thought when every moment is really just a complex equation of events?