Virtue however is concerned with emotions and actions, and it is only voluntary actions for which praise and blame are given; those that are involuntary are condoned, and sometimes even pitied. Hence it seems to be necessary for the student of ethics to define the difference between the Voluntary and the Involuntary…

It is then generally held that actions are involuntary when done (a) under compulsion or (b) through ignorance; and that (a) an act is compulsory when its origin is from without, being of such a nature that the agent, who is really passive, contributes nothing to it: for example, when he is carried somewhere by stress of weather, or by people who have him in their power. But there is some doubt about actions done through fear of a worse alternative, or for some noble object… It is an open question whether such actions are voluntary or involuntary. A somewhat similar case is when cargo is jettisoned in a storm; apart from circumstances, no one voluntarily throws away his property, but to save his own life and that of his shipmates any sane man would do so. Acts of this kind, then, are ‘mixed’ or composite; but they approximate rather to the voluntary class. For at the actual time when they are done they are chosen or willed; and the end or motive of an act varies with the occasion, so that the terms ‘voluntary’ and ‘involuntary’ should be used with reference to the time of action; now the actual deed in the cases in question is done voluntarily, for the origin of the movement of the parts of the body instrumental to the act lies in the agent; and when the origin of an action is in oneself, it is in one’s own power to do it or not. Such acts therefore are voluntary, though perhaps involuntary apart from circumstances — for no one would choose to do any such action in and for itself.

Aristotle, Nicomachean Ethics, III, i. 1-6