c) The theological argument for our thesis is well stated by St. Thomas. He distinguishes between _obstinatio perfecta_ and _obstinatio imperfecta_ and says: Perfect obstinacy exists only in hell. Imperfect obstinacy is that of a sinner who has his will so firmly set on evil that he is incapable of any but the faintest impulses towards virtue, though even these are sufficient to prepare the way for grace.(543) “If any one falls into sin after having received Baptism,” says the Fourth Lateran Council, “he can always be restored by sincere penance.”(544) As the power of the keys comprises all sins, even those against the Holy Ghost, so divine grace is held out to all sinners. The Montanistic doctrine of the unforgivableness of the “three capital sins” (apostasy, murder, and adultery) was already condemned as heretical during the life-time of Tertullian. The sinner can obtain forgiveness only by receiving the sacrament of Penance or making an act of perfect contrition.(545) Justly, therefore, does the Church regard despair of God’s mercy as an additional grievous sin. If the rigorists were right in asserting that God in the end absolutely abandons the sinner, there could be no hope of forgiveness, and despair would be justified. *Thesis III: The heathens, too, receive sufficient graces for salvation.* This proposition may be qualified as _certa_. Proof. The “heathens” are those whom the Gospel has not yet reached. They are called _infideles negativi_ in contradistinction to the _infideles positivi_, _i.e._ apostates and formal heretics who have fallen away from the faith. We assert that God gives to the heathens sufficient grace to know the truth and be saved. Pope Alexander VIII, on December 7, 1690, condemned Arnauld’s Jansenistic proposition that “pagans, Jews, heretics, and others of the same kind experience no influence whatever from Christ, and it may therefore be rightly inferred that there is in them a nude and helpless will, lacking sufficient grace.”(546) A proposition of similar import, set up by Quesnel, was censured by Clement XI.(547) Though not formally defined, it is a certain truth—deducible from the infallible teaching of the Church—that God does not permit any one to perish for want of grace.