The Complete Aristotle (eng.)

are to be chosen, and in
return for what, it is not easy to state; for there are many
differences in the particular cases.
    But if some one were to say that pleasant and noble objects have
a compelling power, forcing us from without, all acts would be for
him compulsory; for it is for these objects that all men do
everything they do. And those who act under compulsion and
unwillingly act with pain, but those who do acts for their
pleasantness and nobility do them with pleasure; it is absurd to
make external circumstances responsible, and not oneself, as being
easily caught by such attractions, and to make oneself responsible
for noble acts but the pleasant objects responsible for base acts.
The compulsory, then, seems to be that whose moving principle is
outside, the person compelled contributing nothing.
    Everything that is done by reason of ignorance is not voluntary;
it is only what produces pain and repentance that is involuntary.
For the man who has done something owing to ignorance, and feels
not the least vexation at his action, has not acted voluntarily,
since he did not know what he was doing, nor yet involuntarily,
since he is not pained. Of people, then, who act by reason of
ignorance he who repents is thought an involuntary agent, and the
man who does not repent may, since he is different, be called a not
voluntary agent; for, since he differs from the other, it is better
that he should have a name of his own.
    Acting by reason of ignorance seems also to be different from
acting in ignorance; for the man who is drunk or in a rage is
thought to act as a result not of ignorance but of one of the
causes mentioned, yet not knowingly but in ignorance.
    Now every wicked man is ignorant of what he ought to do and what
he ought to abstain from, and it is by reason of error of this kind
that men become unjust and in general bad; but the term
‘involuntary’ tends to be used not if a man is ignorant of what is
to his advantage—for it is not mistaken purpose that causes
involuntary action (it leads rather to wickedness), nor ignorance
of the universal (for that men are blamed), but ignorance of
particulars, i.e. of the circumstances of the action and the
objects with which it is concerned. For it is on these that both
pity and pardon depend, since the person who is ignorant of any of
these acts involuntarily.
    Perhaps it is just as well, therefore, to determine their nature
and number. A man may be ignorant, then, of who he is, what he is
doing, what or whom he is acting on, and sometimes also what (e.g.
what instrument) he is doing it with, and to what end (e.g. he may
think his act will conduce to some one’s safety), and how he is
doing it (e.g. whether gently or violently). Now of all of these no
one could be ignorant unless he were mad, and evidently also he
could not be ignorant of the agent; for how could he not know
himself? But of what he is doing a man might be ignorant, as for
instance people say ‘it slipped out of their mouths as they were
speaking’, or ‘they did not know it was a secret’, as Aeschylus
said of the mysteries, or a man might say he ‘let it go off when he
merely wanted to show its working’, as the man did with the
catapult. Again, one might think one’s son was an enemy, as Merope
did, or that a pointed spear had a button on it, or that a stone
was pumicestone; or one might give a man a draught to save him, and
really kill him; or one might want to touch a man, as people do in
sparring, and really wound him. The ignorance may relate, then, to
any of these things, i.e. of the circumstances of the action, and
the man who was ignorant of any of these is thought to have acted
involuntarily, and especially if he was ignorant on the most
important points; and these are thought to be the circumstances of
the action and its end. Further, the doing of an act that is called
involuntary in virtue of ignorance of this sort must be painful and
involve repentance.
    Since that which is done under compulsion or by reason of
ignorance is involuntary, the voluntary would seem to be that of
which the moving principle is in the agent himself, he being aware
of the particular circumstances of the action. Presumably acts done
by reason of anger or appetite are not rightly called involuntary.
For in the first place, on that showing none of the other animals
will act voluntarily, nor will children; and secondly, is it meant
that we do not do voluntarily any of the acts that are due to
appetite or