Why would Augustine, the one who introduced the doctrine of original sin into Christianity in the first place, teach that infants were damned, if he didn’t believe it to be necessarily and logically implied?
Actually, the first Church Father known to have at least alluded to the doctrine of original sin is Justin Martyr in his Dialogue with Trypho 88:4 (A.D. 155). There were three prevalent theories between the East and West by the time of Augustine, and they were all based on the teachings of St. Paul (Rom. 5:12-21; 1 Cor. 15:22).
St. Augustine:
"Who can doubt that non-baptized infants, having only original sin and no burden of personal sins, will suffer the lightest condemnation of all? I cannot define the amount and kind of their punishment, but
I dare not say it were better for them never to have existed than to exist there"
In Contra Julianum 5.11
Much of what Augustine wrote on salvation was prompted by his controversy with Pelagius and his heretical teachings. He was defending the theology of original sin in its fundamental form which included the necessity of infant baptism as a means of removing the stain of original sin. Unfortunately, to be consistent, he felt compelled to maintain that an unbaptised infant which died was eternally damned.
Augustine’s soteriology depended on the fundamental Catholic belief that no human being can merit the initial grace of justification and forgiveness. And this grace, which cannot be received by any preceding natural merit of ours, can only be received through baptism. This explains why Augustine was so theologically strict and legalistic in his views.
True, he did accept the idea of baptism of desire and of blood, but it seems he did not see these informal baptisms as applying to infants. Still he was disconcerted by the thought of unbaptised infants being punished along with unrepentant sinners. Thus he believed that these infants would somehow face the least punishments. But these sufferings wouldn’t be so harsh that it would have been better for these infants to never have existed at all. Anyway, the Church has rejected Augustine’s rigid views in this matter, as theological opinions are prone to be.
(Pope Zosimus at the Council of Carthage XVI, Canon 3, Denzinger, 30th edition, p.45, note 2).
Of course, Trent > Pope Zosimus. But, it demonstrates that this belief in infant damnation went right to the top in the western church by the 5th century.
The Council of Carthage ?:
"It has been decided likewise that if anyone says that for this reason the Lord said: “In my house there are many mansions”: that it might be understood that in the kingdom of heaven there will be some middle place or some place anywhere where happy infants live who departed from this life without baptism, without which they cannot enter into the kingdom of heaven, which is life eternal, let him be anathema."
This definitely is not an infallible statement about the eternal fate of unbaptized infants, but rather a condemnation of anyone who uses this Scriptural passage of"many mansions" to mean baptism is unnecessary.
The Council of Carthage was a regional council which consisted of African bishops. It rejected the teaching of Pelagius. In these words, it condemned his opinion that infants “do not contract from Adam any trace of original sin, which must be expiated by the bath of regeneration that leads to eternal life”. The council declared that “even children who of themselves cannot have yet committed any sin are truly baptised for the remission of sins, so that by regeneration they may be cleansed from what they contracted through generation”. It was also added that there is no “intermediate or other happy dwelling place for children who have left this life without Baptism, without which they cannot enter the kingdom of heaven, that is, eternal life” on the grounds of Pelagius’ belief. Meanwhile, this council did not explicitly endorse all aspects of Augustine’s stern view about the destiny of infants who die without Baptism. Pope Zosimus only ratified the council’s condemnation of Pelagius and his heretical views on the necessity of Baptism.
Keep in mind that when the Church acknowledges a baptism of desire or baptism of blood, it isn’t teaching something “in addition” to water baptism. Rather, the Church acknowledges that there are other means by which God may effect the equivalence of grace imparted at baptism by the soul’s desire or martyrdom. Further God is free to effect the graces of baptism onto a “formally” unbaptized infant. Thus such an infant will have been baptized by God in an extenuating way even if the formal rite had not been performed upon the birth of the infant. Meanwhile, in all cases of baptism, God sanctifies the soul with His healing and regenerating grace, without which no soul can enter Heaven (cf. Rev. 21:27).
Moreover, it’s questionable that this text is actually from the Council. As the Catholic Encyclopaedia points out immediately preceding that paragraph: “The following, says Surius, is found in this place in a very ancient codex. It does not occur in the Greek, nor in Dionysius. Bruns relegates it to a foot-note.”
newadvent.org/fathers/3816.htm
The Catechism of the Catholic Church:
‘The Church does not know of any means other than Baptism that assures entry into eternal beatitude; this is why she takes care not to neglect the mission she has received from the Lord to see that all who can be baptized are “reborn of water and the Spirit.” God has bound salvation to the sacrament of Baptism, but he himself is not bound by his sacraments.’ [n.1257]
:heaven:
That sums up the Catholic view beautifully.