I'm not Catholic, and Episcopalians don't really need to believe in anything (This statement is really more of a joke than anything), but I've been thinking of the concept of original sin. I'm not exactly sure whether the concept of original sin is something that is around in Anglican thought very much: regardless, we never really talk about it, mainly because I imagine it is "kind of a downer." That's understandable, because it kind of is. I mean, it's not as bad as Calvin's idea of "total depravity" (although that would be a sweet band name). However, the Episcopal church has also kind of moved away from an Augustinian idea of how sin works, so we don't really see it as a necessary argument to have.
To be honest, Augustine doesn't really seem to me to have a cogent idea on sin throughout his work. That's not bad, because we all change our minds. But he makes the argument that evil doesn't really exist: saying that evil is a lot like cold or darkness. Evil is merely the absence of good. That sounds compelling, right? But at the same time, he somehow believes that Satan is around and is a manifestation of evil. That always seemed to me to be a contradictory position, and I want to argue in better faith than "Well, looks like he was still a Manichee." Not only that, but if evil is merely the absence of good, then how does there become a stain of evil that is passed down in a hereditary manner from the beginning of people? I just don't think that the concept of original sin was thought very well through in the light of his philosophy of evil.
However, by rejecting that notion of original sin, I don't want to follow a lot of newer theologians and say that sin has no real place in our worldview. I think that is a temptation, but it is very clear that people are doing sinful/bad things in the world, whether through negligence or through actual willful harming of other people. To say that that is not important in how the world works seems to basically be giving a free pass to people who have been benefiting off of harming others (ie. oppression). Ignoring the fact that people do bad things does not make those bad things go away, nor does it help the people harmed by those actions.
Karl Rahner has an interesting concept of original sin that I think is possibly the most cogent one in recent history. He said that it is impossible to live in the world without causing harm to others. Perhaps not on purpose, but it still happens. As more and more people willfully or ignorantly harm other people, we live in a world where it is impossible to exist and not cause harm or oppression to other people: that is original sin. I think that conception of it helps with certain things: first of all, it is realistic and not some sort of weird genetic metaphysical state (a la Augustine). Yet again, it also posits sin as something not completely individualistic, and therefore something that can be used to guilt people into paralysis, but as a reality of society. There is an amount of negative things that we do that are at least partially out of our control. I think it moves past the debt/guilt model of sin that seems to be the real problem those who dislike the notion of sin are getting at.
I'm not exactly sure that I have a full thought here, more along the lines of just a couple of thoughts collected. If you have anything that you want to say on the subject, then feel free to add to the discussion.