Every event has a cause-that is ... for every event e1 there exists an event e2 (or a class of events e2, e3 ...) which precedes e1 and of which e1 is a necessary consequence.... If we assent to this statement then your "choice" to do A rather than B, whatever may have been at the time your sensation of freedom from any constraint, was entirely necessitated. You could not have done otherwise and hence, according to this conception of freedom, were not free.