Will, Voluntary, Compulsion

According to Aristotle, a 'voluntary' act is one performed without 'compulsion', with 'compulsion' defined as movement originating outside the agent. However, he seems unwilling to, accordingly, deny that the tossing of goods from a ship, to lighten its load during a storm, has an involuntary dimension. In contrast, the unequivocal application of his classification distinguishes between pulling a trigger while another gun is pointed at one's head, and pulling it during sneezing as an allergic reaction to pollen. At bottom, Aristotle definition of 'compulsion' fails to distinguish between the perception of some external phenomenon and an external efficient cause of a physiological event. Even the direst of circumstances does not transform an exercise of Will into an involuntary act. Thus, any response to compulsion e. g. qua perceived threat is voluntary.