done through ignorance
is involuntary."

_I answer that,_ If ignorance causes involuntariness, it is in so far
as it deprives one of knowledge, which is a necessary condition of
voluntariness, as was declared above (A. 1). But it is not every
ignorance that deprives one of this knowledge. Accordingly, we must
take note that ignorance has a threefold relationship to the act of
the will: in one way, "concomitantly"; in another, "consequently"; in
a third way, "antecedently." "Concomitantly," when there is ignorance
of what is done; but, so that even if it were known, it would be
done. For then, ignorance does not induce one to wish this to be
done, but it just happens that a thing is at the same time done, and
not known: thus in the example given (Obj. 3) a man did indeed wish
to kill his foe, but killed him in ignorance, thinking to kill a
stag. And ignorance of this kind, as the Philosopher states (Ethic.
iii, 1), does not cause involuntariness, since it is not the cause
of anything that is repugnant to the will: but it causes
"non-voluntariness," since that which is unknown cannot be actually
willed. Ignorance is "consequent" to the act of the will, in so far
as ignorance itself is voluntary: and this happens in two ways, in
accordance with the two aforesaid modes of voluntary (A. 3). First,
because the act of the will is brought to bear on the ignorance: as
when a man wishes not to know, that he may have an excuse for sin,
or that he may not be withheld from sin; according to Job 21:14: "We
desire not the knowledge of Thy ways." And this is called "affected
ignorance." Secondly, ignorance is said to be voluntary, when it
regards that which one can and ought to know: for in this sense "not
to act" and "not to will" are said to be voluntary, as stated above
(A. 3). And ignorance of this kind happens, either when one does not
actually consider what one can and ought to consider; this is called
"ignorance of evil choice," and arises from some passion or habit: or
when one does not take the trouble to acquire the knowledge which one
ought to have; in which sense, ignorance of the general principles of
law, which one to know, is voluntary, as being due to negligence.
Accordingly, if in either of these ways, ignorance is voluntary, it
cannot cause involuntariness simply. Nevertheless it causes
involuntariness in a certain respect, inasmuch as it precedes the
movement of the will towards the act, which movement would not be