ORIGINAL SIN IS IRREVOCABLE/INFALLIBLE CATHOLIC DOCTRINE

Catholics and Protestants hold that since the fall from God, three things have happened. 

We are all born cut off from God. 

We are all born as sinners.

We are all born with an inborn propensity to sin. 

Though we are made in the image of God that image is very tarnished.  The danger is that we will abuse that image to feel like we are the Gods.  God fixes us akin to how an optician fixes your vision.  Your eyes are opened and the more you look the more you want to change and the more you change.  It is obvious though that things that fix the problem such as baptism do nothing like that at all!

Nothing of Catholicism makes any sense unless you know of and accept the doctrine that all people as a result of Adam's sin come into existence separated from and estranged from God. They have no relationship with him and the damage this does makes them more inclined to do wrong and to sin. Jesus supposedly shed his blood in death to fix this sin and offer sacrifice for it and you get freed from it through his blood in water baptism. This is the doctrine of original sin.

Council of Trent, Decree on Original Sin, 1546: “4. If any one denies that infants newly born from their mothers’ wombs, even though they be sprung from baptized parents, are to be baptized; or says that they are baptized indeed for the remission of sins, but that they derive nothing of original sin from Adam, which has need of being expiated by the laver of regeneration for the obtaining of life everlasting,—whence it follows as a consequence, that in them the form of baptism, for the remission of sins, is understood to be not true, but false,—let him be anathema. For that which the apostle has said, By one man sin entered into the world, and by sin death, and so death passed upon all men in whom all have sinned, is not to be understood otherwise than as the Catholic Church spread everywhere hath always understood it. For, by reason of this rule of faith, from a tradition of the apostles, even infants, who could not as yet commit any sin of themselves, are for this cause truly baptized for the remission of sins, that in them that may be cleansed away by regeneration, which they have contracted by generation. For, unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God.”

COT, Decree on Original Sin, 1546: “2. If any one asserts that the prevarication of Adam injured himself alone and not his posterity, and that the holiness and justice, received of God, which he lost, he lost for himself alone and not for us also; or that he being defiled by the sin of disobedience has only transfused death ‘and pains of the body into the whole human race, but not sin also, which is the death of the soul,’ let him be anathema, whereas he contradicts the apostle who says: ‘By one man sin entered into the world, and by sin death, and so death passed upon all men, in whom all have sinned.’ (Rom. 5:12)”.

Pope St Zosimus, Council of Carthage XVI, Original Sin and Grace, 418: “Canon 3. It has been decided likewise that if anyone says that for this reason the Lord said: ‘In my Father’s house there are many mansions’ [John 14:2]: that it might be understood that in the kingdom of heaven there will be some middle place or some place anywhere else where blessed [beati] 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. For when the Lord says: ‘Unless a man be born again of water and the Holy Ghost, he shall not enter into the kingdom of God’ (Jn. 3:5), what Catholic will doubt that he will be a partner of the devil who has not deserved to be a coheir of Christ? For he who lacks the right part will without doubt run to the left.” (Denzinger 102, footnote 2.)

The Catechism of the Catholic Church,

388 With the progress of Revelation, the reality of sin is also illuminated. Although to some extent the People of God in the Old Testament had tried to understand the pathos of the human condition in the light of the history of the fall narrated in Genesis, they could not grasp this story's ultimate meaning, which is revealed only in the light of the death and Resurrection of Jesus Christ. We must know Christ as the source of grace in order to know Adam as the source of sin. The Spirit-Paraclete, sent by the risen Christ, came to "convict the world concerning sin", by revealing him who is its Redeemer.

389 The doctrine of original sin is, so to speak, the "reverse side" of the Good News that Jesus is the Savior of all men, that all need salvation and that salvation is offered to all through Christ. The Church, which has the mind of Christ, knows very well that we cannot tamper with the revelation of original sin without undermining the mystery of Christ.

390 The account of the fall in Genesis 3 uses figurative language, but affirms a primeval event, a deed that took place at the beginning of the history of man. Revelation gives us the certainty of faith that the whole of human history is marked by the original fault freely committed by our first parents.

Note: Even if today's Catholic Church disagrees that babies are left to be punished forever if they are not baptised, it still acknowledges the right to reinstate that doctrine. That the babies have no pain or are even happy is put forward only as an opinion. In fact the disagreement is over-ridden by how the Church's core doctrine is that Tradition cannot err. The doctrine that unbaptised babies are still happy though they are not in Heaven was invented by St Thomas Aquinas. A doctrine that allows for sinister implications such as the notion that actually sinning venially is better than having original sin is still bad even if the religion does not tease out the implications correctly.

WORKS CONSULTED

CITY OF GOD, St Augustine, Penguin Books, Middlesex, 1986
EVERYMAN’S ROAD TO HEAVEN, Leo J Trese, Geoffrey Chapman, London, 1961
APOLOGETICS AND CATHOLIC DOCTRINE, Most Rev M Sheehan DD, M H Gill & Son, Dublin, 1954
RADIO REPLIES, VOL 1, Frs Rumble and Carty, Radio Replies Press, St Paul, Minnesota, 1938
THE SINNER’S GUIDE, Ven Louis of Granada, TAN, Illinois, 1983
CHRISTIANITY, David Albert Jones OP, Family Publications, Oxford, 1999
THE INSTITUTES OF THE CHRISTIAN RELIGION, John Calvin, Hodder and Stoughton, London 1986
THE FALL AND ORIGINAL SIN, WHAT IS CHRISTIANITY III, WILLIAM MORAN DD, ST PATRICKS COLLEGE, MAYNOOTH, CATHOLIC TRUTH SOCIETY OF IRELAND, 1940