Catechism of the Catholic Church §387 — excerpt
Only the light of divine Revelation clarifies the reality of sin and particularly of the sin committed at mankind's origins. Without the knowledge Revelation gives of God we cannot recognize sin clearly and are tempted to explain it as merely a developmental flaw, a psychological…
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.