that this man will defend himself and strike him back, and that if he had known this, he would not have struck him (which does not affect the sinfulness of the act).  Wherefore, though this man sins through ignorance, yet he is not altogether excused, because, not withstanding, he has knowledge of the sin.  Secondly, this may happen on the part of the ignorance itself, because, to wit, this ignorance is voluntary, either directly, as when a man wishes of set purpose to be ignorant of certain things that he may sin the more freely; or indirectly, as when a man, through stress of work or other occupations, neglects to acquire the knowledge which would restrain him from sin.  For such like negligence renders the ignorance itself voluntary and sinful, provided it be about matters one is bound and able to know.  Consequently this ignorance does not altogether excuse from sin.  If, however, the ignorance be such as to be entirely involuntary, either through being invincible, or through being of matters one is not bound to know, then such like ignorance excuses from sin altogether.

Reply Obj. 1:  Not every ignorance causes involuntariness, as stated above (Q. 6, A. 8).  Hence not every ignorance excuses from sin altogether.

Reply Obj. 2:  So far as voluntariness remains in the ignorant person, the intention of sin remains in him:  so that, in this respect, his sin is not accidental.

Reply Obj. 3:  If the ignorance be such as to exclude the use of reason entirely, it excuses from sin altogether, as is the case with madmen and imbeciles:  but such is not always the ignorance that causes the sin; and so it does not always excuse from sin altogether. ________________________

FOURTH ARTICLE [I-II, Q. 76, Art. 4]

Whether Ignorance Diminishes a Sin?

Objection 1:  It would seem that ignorance does not diminish a sin.  For that which is common to all sins does not diminish sin.  Now ignorance is common to all sins, for the Philosopher says (Ethic. iii, 1) that “every evil man is ignorant.”  Therefore ignorance does not diminish sin.

Obj. 2:  Further, one sin added to another makes a greater sin.  But ignorance is itself a sin, as stated above (A. 2).  Therefore it does not diminish a sin.

Obj. 3:  Further, the same thing does not both aggravate and diminish sin.  Now ignorance aggravates sin; for Ambrose commenting on Rom. 2:4, “Knowest thou not that the benignity of God leadeth thee to penance?” says:  “Thy sin is most grievous if thou knowest not.”  Therefore ignorance does not diminish sin.

Obj. 4:  Further, if any kind of ignorance diminishes a sin, this would seem to be chiefly the case as regards the ignorance which removes the use of reason altogether.  Now this kind of ignorance does not diminish sin, but increases it:  for the Philosopher says (Ethic. iii, 5) that the “punishment is doubled for a drunken man.”  Therefore ignorance does not diminish sin.