It is one of the most overlooked and rejected dogmas. But for Benedict XVI, it is "overwhelmingly obvious." He has talked about it three times in eight days. Without it, he says, Christian redemption "would lose its foundation"
That we do evil may not in itself be sufficient evidence of original sin--some may even mistakenly argue that that power to evil is a necessary consequence or characteristic of freedom. For those who have some vague belief in God, I think a more compelling proof would begin with the awareness that we do not, by our own power, love God. It can also be shown that all creatures love (or should love) God more than themselves. Therefore there is something wrong with us, for which God is not responsible, but some among us are (or were).