I have a question about causality solely when it comes to human behavior. Suppose I argue that the presence of oxygen on Earth was the cause of an office building on fire. It is certainly true that if there had been no oxygen on Earth there would have been no fire. It is also true that if there had been no arsonists or negligent persons, nor any flammable material, there would have been no fire. So is it true that when it is assumed that one of several necessary conditions was the sole and exclusive cause of an effect, then the reasoning is fallacious due to the possibility that humans might have free will which somehow shifts responsibility away from nature or scientific processes?