What started me thinking about this was an NPR "Science Friday" interview I heard last week with mathematician and pop-science writer Amir Aczel, author of a recent book about Pierre Teilhard de Chardin, SJ entitled The Jesuit and the Skull. Although the reviews have been rather mixed, one thing the reviewers seem agreed on was Aczel's depiction of the Church as obscurantist and benighted about science—despite Pius XII's 1950 encyclical Humani Generis, which permitted the "hypothesis" of the origin of the human body by evolution, but which doesn't seem to be on the radar screens of these people. That especially irritated me. True, Teilhard's Jesuit superiors exiled him from his beloved France and refused to let him publish during his lifetime (he died in New York in 1955). That's not how I would have handled him; I would have let him hang his rope himself, as became the Church's normal practice after Vatican II. True, in 1962 the Holy Office (soon to be renamed the Sacred Congregation for the Doctrine of the Faith) issued a monitum (warning) against his recently published writings. But that was reiterated by the CDF in 1981, just before then-Cardinal Ratzinger took over, and has never been rescinded. Having read Teilhard extensively in college, I agree with the monitum, which explicitly prescinds from "questions of the positive sciences" and focuses strictly on theology. On that score, Aczel got it half-right when he repeated, in the interview, that what most concerned ecclesiastical authorities was Teilhard's frank disbelief in the doctrine of original sin. But neither Aczel nor the interviewer, Ira Flatow, showed the slightest understanding of the doctrine. They took for granted that what upset the Church was Teilhard's disbelief in a literal Garden of Eden and expulsion therefrom. By way of developing my proposal, I shall first correct that error.
From a Catholic standpoint, there is no obligation to believe that the truth in the first two chapters of Genesis is expressed literally as opposed to mythically. On both literary and scientific grounds, I myself disbelieve that, just as Teilhard did. But the reality of original sin must all the same be affirmed as de fide, which is indeed part of the truth conveyed by the theologically reworked myths recorded in Genesis 1 and 2. (On this entire topic, I highly recommend Ratzinger's In the Beginning.) The reality is that each of us (with one exception, already noted) is conceived in a state of alienation from God in virtue of our common descent from the first people to disobey God and thus fall from his grace. As the main effect of the first sin, original sin is essentially a negative state and is called 'sin' only by analogy. It is the deprivation of a supernatural state to which we were destined by God and which therefore ought to obtain. That deprivation has effects in turn: death, concupiscence, the darkening of the intellect, and all the suffering normally attendant on animal life. All those things make actual sins inevitable, in a certain way, in the lives of each person who attains the use of reason and freedom. Even though no particular actual sin is inevitable—else it would not be freely committed, and thus would not be actual sin—some-or-other actual sin is inevitable at some-or-other point for each of us who develop enough to exercise freedom of the will. Thus sin becomes a self-sustaining, self-reinforcing system both individually and socially. It's why we become slaves to sin and need a Redeemer. That's why our only hope is Jesus Christ who, as the Truth, makes us free.
But that fact should occasion deeper, contemporary reflection on the idea of the "effects" of original sin. Having read enough about evolution over the years to have an informed layman's opinion—most recently, I have benefited from Francis Collins' The Language of God (2006)—it has always seemed to me that said effects, as a syndrome, are just what one would expect if humans had never been elevated by grace in the first place, but instead had been left with what evolution had bequeathed. Animals get suffer, get sick, and die. For good and ill, they largely governed by instinct. Monogamy is preferred only by a minority; males often fight over territory and females; predators eat prey, who in turn prey on others; and so on. Over time, only the relatively strong and clever survive; the weak and the dull die out. Such is "nature red in tooth and claw." It's "a jungle out there," even when the jungle is asphalt. Despite our special qualities, is there any reason short of divine revelation to believe that we should be, could be, or ever were exempt from all that? Dr. Collins, who once headed the Human Genome Project, reminds us that the difference between our DNA and that of chimpanzees is less than 2%. If we're all that different, it's not because we're all that different animals. And so our evolutionary heritage is, simultaneously, the "base level" from which God elevated our progenitors, and the ambit within which our freedom is circumscribed by original sin as deprivation. Our race as a whole has never got much beyond that because our progenitors, who had indeed been elevated beyond it by grace alone, sunk back into it by their choice to grab at divinity rather than receive it in humility and obedience. They could do that because, though ideally equipped to develop real virtue freely, under divine guidance, they had barely begun the process. And of course it is only the Redemption, promised obliquely by God as recorded in Genesis 3:15, that enables us to do it once anew.
That is why even the baptized have a lot of work to do. There is nothing automatic about "salvation," a word whose root meaning is "healed" or made whole. Once grace justifies us, our free cooperation is necessary to continue the process of our "sanctification"—our being "set apart" for God—and thus the process of our divinization. But any one of us can, if we choose, blow the whole thing. The freedom we have now, which we enjoy by both nature and grace, is immature because it still entails the freedom to go wrong and thus diminish freedom itself—even eliminate it, if we give ourselves over definitively to Satan. In a world at once fallen and redeemed, such immature freedom is a necessary condition for developing into the gloriously free children of his that God means for us to be. But another such condition is that a man who is a divine person, Jesus Christ, has always been both perfectly free and perfectly incapable of sin. And the first manifestation of his person and work in history is this: that one strictly human person, the one by whom Christ entered the world, is the pre-eminent beneficiary and facilitator among us of that mature freedom.