The point is clear — just as Adam’s sin was imputed to us, so Jesus’ righteousness is also imputed to us! (See all of Adrian's post)This leads directly to the question: Was Adam's sin imputed to us? This is the passage being discussed:
Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all men, because all sinned -- for before the Law was given, sin was in the world. But sin is not taken into account when there is no law. Nevertheless, death reigned from the time of Adam to the time of Moses, even over those not sinning in the likeness of Adam's transgression, who was a pattern of the one to come. (Romans 5:12-14)This passage is at the heart of the question: exactly what do we mean by "original sin"? There is more than one view of it. I know that some read this and see something along these lines: "Adam sinned. His sin was accounted to us: in Adam's one particular sin, everyone was accounted sinful."
I would like to point out a few things in this passage that make me consider the "imputed sin" interpretation to be an unlikely understanding of original sin. First, the passage does not focus only on the primeval sin at the dawn of human history, but takes into account the broad sweep of human history full of sin and death: "before the Law was given, sin was in the world", and "nevertheless, death reigned from the time of Adam to the time of Moses". Also the passage seems to indicate that everyone else sinned in their own rights. It makes the distinction between Adam's trangression and the sins of the rest of the people who lived before Moses, that while Adam had a commandment and transgressed it, the others did not have the same transgression in that they had no explicit law. Paul had developed an argument from the natural law and human conscience earlier in the letter. So while the sin of others was not accounted because there was no law, death still reigned.
On the view that the whole discussion is really about one primeval sin that is put to our account, there would be no need to argue the status of peoples' own sins up until the time of Moses, or even whether the other people had sinned at all. The passage does not say that Adam's guilt was imputed to others; it says that all sinned and references the broad sweep of history.
The view of imputing one primeval sin has never been accepted among Christians as a whole, but only regionally. There has always been at least one dissenting voice within the church: the Eastern Orthodox. Some Eastern Orthodox theologians I've read say that Rome based her view of imputation from Adam based on a faulty Latin interpretation of the Greek. The Eastern Orthodox hold a view of original sin which may possibly be more ancient than Rome's, where each of us is held responsible for his own sin, not for Adam's. If this is the case, then Adam's sin was worse than "imputed"; it opened a door so that sin and death became a part of the fabric of the world, and each of us participated in the guilt of the world by our own sins.
Death and sin enter the world not by mere imputation that leaves us unaffected and untransformed, but in reality so that even the thoughts of our hearts turn to evil. The Calvinists in particular tend to emphasize that our sinful condition is not a matter of imputing a sin to us that we did not commit, but that there is a deep-seated sinfulness in us that affects everything we do. The Calvinists write about TULIP and have much to say about total depravity and the sinfulness of our lives; in this context it is especially surprising to arrive at a conversation on atonement and see original sin referenced as a matter of imputation rather than a matter of depravity. Atonement also tackles mankind's depravity, our evil inclination. By the nature of the problem, atonement must cause the death of our evil inclination, must cause our return to God, must effect the reversal of our depravity: our repentance.
The catastrophic effects which Calvinists so eloquently describe in their doctrine of Total Depravity are not really consistent with a view that Adam's sin comes to us only by imputation, that we are affected only by representation. We ourselves are direct participants in the fall of the world. And as redeemed, we are direct participants in the new creation and the healing of the world.
If we ourselves participate in the fall of the world, if our evil inclination and our depravity are considered part of the problem, then that leads to a different view of the nature of the atonement. The atonement involves more than substitution, more than representation, more than imputation; the atonement also brings about a new reality, makes us part of a new creation.
Please note that I have never argued against Christ being our substitute. There is a very real substitution that is part of the atonement. The problem comes only when we try to make it the whole; for that leaves everything else -- the defeat of depravity and the evil inclination, repentance, faith, the new creation -- out of the atonement. If you'll pardon a bad joke, it's a view of atonement which is very limited.