Almost a year ago, I wrote a post about the internal causes of sin according to Aquinas: ignorance, weakness, and malice. This year I picked up the thread in the Second Part of the Summa Theologica and read about the external causes of sin. Reading this section brought to mind comedian Flip Wilson’s character Geraldine and her famous line, “The Devil made me do it!” What would Aquinas think about Geraldine’s statement?
Just as Aquinas identifies three internal causes of sin, he points to three possible external causes as well: God, the Devil, and Man. On the first of the three, God, I agree with Aquinas’s conclusions, although his reasoning sometimes seems lacking. God does not create evil and does not cause sin directly. As Sustainer of the world, He is the cause of the act of sin as an action, but this still does not make Him responsible for the sin. God also withdraws his grace from each person, but as a punishment, not as a cause of sin.
St. Thomas has to talk over the possibility of God causing sin, because he has established earlier that only God or the will itself can move the human will. The Devil has no power directly to move the human will. (Whew!) So in this way, Geraldine was definitely wrong. The Devil, though, does have the power of persuasion, and he can directly affect our sensitive appetites and our imaginations. So if Geraldine meant that the Devil induced her to sin in one of these ways, Aquinas would agree. In an ominous passage, the Dominican theologian notes that the Devil can and does sometimes completely overwhelm a person’s reason in possession and cause evil acts; but in these cases the human bears no culpability for sin since he has no means of control or resistance.
If God doesn’t cause sin, and the Devil can only suggest sin, we have only one other external source to blame for our sins: another human being. Thomas acknowledges that a man can lead another to sin through suggestion, just as the Devil does. But then he spends the bulk of this section on the doctrine of original sin. As I read it, the sin of Adam, in which we all participated by proxy, gets passed down only through men (“Sin came into the world through one man,” says Paul, excluding Eve, the first to sin, from the explanation); original sin comes to every human being who has a human father; a person formed miraculously would not inherit sin merely from having human flesh; no sin but original sin is passed down from parent to child; and the Holy Spirit purified Mary when He came upon her only because holiness befits the house of God. This section puzzles me, because it seems opposed to Catholic doctrine as I understand it. I hesitate to say anything about it more directly, especially while I still live in Italy.