Finally a way to prove that free will occurs. If A always leads to B and B always leads to C, and if C does not follow after A, then a free choice has occurred. Example: Whenever I get drunk I always fall asleep an hour later because I always sit on the couch after getting drunk. I get drunk one night then sit at the kitchen table and do not fall asleep. Boom: free will. I call this argument the argument from slippery slope. It illustrates that even though a certain course of events is most natural the introduction of a decision can derail the natural course of causation.