Eudemian Ethics

Now that this is concluded, and as the voluntary has been found not to be defined by appetition, nor yet by purposive choice, it therefore remains to define it as that which is in accordance with thought.

Now the voluntary seems to be the opposite of the involuntary; and acting with knowledge of either the person acted on or the instrument or the result (for sometimes the agent knows that it is his father but does not intend to kill him but to save him—as the Peliads did—or knows that what he is offering is a drink but offers it as a love-charm or wine, when really it is hemlock) seems to be the opposite of acting without knowing the person acted on, the instrument and the nature of the act, through ignorance and not by accident. But to act through ignorance of the act, the means and the person acted on is involuntary action.

Therefore the opposite is voluntary. It follows then that all the things that a man does not in ignorance, and through his own agency, when it is in his power not to do them, are voluntary acts, and it is in this that the voluntary consists; and all the things that he does in ignorance, and through being in ignorance, he does involuntarily.

But since to understand or know has two meanings, one being to have the knowledge and the other to use it, a man who has knowledge but is not using it would in one case be justly described as acting in ignorance but in another case unjustly— namely, if his non-employment of the knowledge were due to carelessness. And similarly one would be blamed for not having the knowledge, if it were something that was easy or necessary and his not having it is due to carelessness or pleasure or pain. These points therefore must be added to our definition.

Let this, then, be our mode of definition about the voluntary and involuntary.