What Is Original Sin, and Why Does It Affect Us?
The Most Verifiable Doctrine
The writer G. K. Chesterton once remarked that original sin is the only part of Christian theology that can really be proved. He meant that you only have to look at the world — or into your own heart — to see that something has gone wrong. We know what is good, and we fail to do it. We want to love, and we act selfishly. History is full of extraordinary goodness and appalling cruelty, often in the same people.
Christianity has a name for the root of this condition: original sin. It is one of the most misunderstood teachings of the faith. Many people imagine it means we are blamed for something someone else did, or that human beings are evil through and through. The Church teaches neither.
What Happened in the Beginning
The story is told in Genesis 2–3. God created our first parents in friendship with Him, in a state of holiness and harmony. They were at peace with God, with each other, with creation and within themselves. They had a share in God’s own life — what theologians call “original holiness and justice” (CCC 375–376).
They were also free. God gave them one command, as a sign that they were creatures who depended on Him. Tempted by the devil, they chose to disobey. They wanted to be “like God” on their own terms, without Him (Genesis 3:5). The Catechism describes this first sin as man preferring himself to God (CCC 398).
The account uses figurative language — a garden, a tree, a serpent. But the Church teaches that it describes a real event at the beginning of human history (CCC 390). See How Should We Read Genesis?
What Was Lost
The consequences were immediate. The harmony was broken. Adam and Eve hid from God. They blamed each other. Their relationship became marked by tension and domination. Work became toil. Suffering entered the world, and death came with it (CCC 399–400).
Most importantly, they lost the gift of original holiness — the share in God’s life they had received not only for themselves but for the whole human race.
Why It Affects Us
Here is where the misunderstanding usually begins. If Adam and Eve sinned, why should we suffer for it?
The answer is that original sin is not a personal sin we committed. The Church is careful to say it is “contracted,” not “committed” (CCC 404). We are not guilty of Adam’s act in the way he was. Rather, we are born into the condition that resulted from it.
Think of it like an inheritance. If a man inherits a great fortune and squanders it, his children are born poor — not because they did anything wrong, but because he no longer has the fortune to pass on. Our first parents received the gift of holiness for all humanity. When they lost it, they could only hand on a human nature without it. We are born, as it were, without the inheritance we were meant to have.
St Paul puts it plainly: “Sin came into the world through one man and death through sin, and so death spread to all men because all men sinned” (Romans 5:12).
Wounded, Not Destroyed
The Catholic Church teaches that human nature, after the Fall, is wounded but not totally corrupted (CCC 405). This is an important point, and one on which Catholics differ from some Protestant traditions.
Our minds can still know truth. Our wills can still choose good. Human beings can still create great art, show real kindness and seek God. But our nature is weakened. Our minds are darkened, so that we struggle to see the truth clearly. Our wills are weakened, so that we struggle to do what we know is right. And we experience an inclination towards sin that the Church calls concupiscence (CCC 405, 1264).
That is why the Christian life is a struggle. St Paul described it in words everyone recognises: “I do not do what I want, but I do the very thing I hate” (Romans 7:15).
What Baptism Does
The good news is that God did not abandon us. Immediately after the Fall, He promised a Redeemer who would crush the serpent’s head (Genesis 3:15). That promise was fulfilled in Jesus Christ, the “new Adam,” whose obedience undoes Adam’s disobedience. “As in Adam all die, so also in Christ shall all be made alive” (1 Corinthians 15:22).
Through Baptism, original sin is washed away and we receive again the share in God’s life that was lost (CCC 405, 1263). This is one reason the Church baptises infants: she does not want to delay the gift of grace.
Baptism does not, however, remove all the effects of the Fall. We still suffer, we still die, and we still feel the pull of concupiscence. The Church teaches that this inclination is not itself a sin. It is left in us for the struggle, so that with God’s grace we may grow in virtue and freely choose Him.
The One Exception
The Church teaches that one human person was preserved from original sin from the very first moment of her existence: the Blessed Virgin Mary. This is the doctrine of the Immaculate Conception, defined in 1854. Mary was redeemed by Christ like everyone else, but in an anticipated way, so that she could be a fitting mother for the Son of God.
Why This Doctrine Is Good News
At first, original sin can sound like a gloomy teaching. In fact it is deeply hopeful.
It explains the world honestly. It takes seriously both human greatness and human failure. We are not simply good, as some optimists claim, and we are not simply evil, as cynics believe. We are good creatures who have been wounded.
It frees us from despair. Our struggles with sin do not mean that something is uniquely wrong with us. They are part of the common human condition, and God has provided the remedy.
It points to Christ. We need a Saviour because we cannot heal ourselves. The doctrine of original sin is the backdrop against which the Gospel shines.
At the Easter Vigil, the Church sings a hymn called the Exsultet, which dares to say of Adam’s sin: “O happy fault, that earned so great, so glorious a Redeemer!” God did not merely repair the damage. He gave us something greater than we lost: His own Son.