How do we know the doctrine of original sin is true?

Original sin, rooted in the actions of Adam, asserts that all humanity shares in the consequences of his transgression. Romans 5:12 articulates this reality: 'Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned.' This foundational doctrine illustrates that death is not merely an individual event but a shared human condition stemming from a single act of disobedience. The universality of death confirms the pervasive impact of Adam's sin, demonstrating the desperate need for salvation through Christ, the second Adam, who redeems and restores life to those who are His.