I said I would get to this sooner or later, so here it is. But this is really just me thinking out loud. I'm not at all sure that there really is a consistent reconciliation between the belief that there is no historical Adam and orthodox Christianity. And, frankly, it seems obvious to me that many who deny the historical Adam don't want to reconcile with it. One of the reasons they have adopted it so willingly is because they want to sink orthodox Christianity, so why look to reconcile anything? But for those who do, there MAY be an option.
I've argued before that there is simply no reason to reject a historical Adam, but if you do, there is only one route to take if one is to remain orthodox in doing so.
But let me first lay out why rejecting a historical Adam, and not adopting what I will suggest below, leads to one of two heresies that don't simply undermine orthodoxy, but the biblical testimony as a whole.
The first of these heresies is Gnosticism. The Gnostics believed that God exists in pure spirit and light, and therefore, the closer one gets to spirit, the more like God he becomes. From this God broke off little gods called aeons, and then other aeons broke off from them. Somewhere down the line, one of those aeons, called the Demiurge, decided to capture spirits in a physical world. The physical world is a prison, and the reason why people do what they do in terms of evil is because this physical prison makes them do it. The very nature of being physical, then, is evil. One cannot do otherwise. He is trapped. Hence, the gnostic view of evil and sin is that it exists because of man's physical nature. It is his ontology that is inherently evil. What this means is that he must be saved from his physical self and become spirit again. This is a platonic dualism where matter is evil and spirit is good.
Now, if Adam never existed, then there is no fall that occurred through him, which many take to mean that our inclinations toward evil don't come from a fallen nature, but from our very physical/biological makeup. What we end up with is a gnostic view of evil, where we must simply escape the physical world, since it is evil by nature.
This, of course, is rejected by orthodox Christianity, because God redeems the physical world and our physical bodies in the resurrection. If the physical world and our physical bodies naturally function in these destructive ways, then one cannot redeem them. He can only get rid of them or exchange them for a different ontology. In essence, as Koester notes:
The cosmos has its divine order, but human beings are not granted their full share in this divine universe because they are caught in the realm of sense perception and matter, disorder and mortality, and are subject to Heimarmene, the power of fate . . . But salvation cannot take place within the realm of the visible world, which is, by definition, the cause of the dilemma (1982: 1:202).
On the other hand, if we are good by nature, or blank slates, this is the heresy of Pelagianism. I see this as the road that many people who deny the historical Adam are taking. Pelagius argued that if God commanded people to do good in Scripture, that meant that humans were capable of doing good. Hence, there could be no fallen nature, where men were guilty for/cursed by Adam's sin.
If this is true, however, then men could potentially be good without the gospel. In other words, the gospel is not really a necessity for any man who just obeyed. Hence, Pelagius actually believed that certain people, like Abraham and Job, didn't need the gospel.
This is rejected by orthodox Christianity because it undermines the necessity of the gospel and it also ignores why sin and disobedience are so universal. If men were basically good, or were a blank slate, you would, in fact, have men who were perfect; but there are no men who are. So why is this? Why do people have evil inclinations. Pelagianism doesn't explain this or give an account for texts in Scripture that argue that the thoughts of a man are evil from the time he is young. Pelagianism is a denial of the universality of sin and the fallen cosmos. In essence, then, death is natural and so are all of the natural evils in the world; but in this way, Pelagianism must assume a Gnostic view of the cosmos, namely, that it is ontologically deficient and brings about suffering because God made it that way.
But if one denies the historical Adam that unifies mankind under one curse, then what options does he have but to conclude that the inclinations that man has toward sin are either ontological (as in Gnosticism) or just a matter of individual choice based upon cultural influence (as in Pelagianism)? In Gnosticism, the Creator is evil because he makes an evil world, or at least, a world inclined toward evil. In Pelagianism, God creates a world that is supposedly free of any inclination toward evil, but becomes filled with it nonetheless. If Jesus were to tell Pelagius that a good tree bears good fruit and cannot bear bad fruit, I'm not sure what he would say but that each individual makes himself good or bad. But this fails to answer the question of where the evil influence of society came from if all was made good and there is no universal condition of man where he is inclined toward self-worship/evil.
Furthermore, if men receive the gospel, they do so as a good work by which they are saving themselves. Sure, God provided the ability for them to get that second chance of being good people, but they have merited their salvation for themselves by performing that good work. They have plenty to boast about before God. There is no need for prevenient grace or effectual grace, as in the synergistic and monergistic systems, as there is no fallen nature from which man must be born again in order to do the greatest work that one could ever do, i.e., receive the Lordship of Jesus Christ through the gospel. Man receives "grace" from God by being given his free human nature and reason to receive God's Word. Grace is revelation then, not an empowerment that is brought on by one's salvific relationship with God.
I supposed we could discuss these issues 'til the cows came home, but it is enough to say that orthodox Christianity rejected these two views for a reason, and that reason is because they undermine the gospel.
But one is left with only these two options if he rejects the historical Adam, that is, if he rejects my next suggestion along with rejecting the historical Adam, and that is this: That he somehow posits that the first group of humans, who the Bible represents with a figure called "Adam," made a covenant with God and broke it as a group, much like Israel had a pact with God and broke it, and were subsequently punished as a group for it. Hence, the only way to maintain orthodox Christianity in denying a historical Adam is to keep the historical fall. If both go, it all goes.
It all goes because if matter is ontologically evil, then there can be no resurrection, no God in the flesh redeeming flesh, no new creation of the cosmos, no sanctification while in the body here. In essence, the Gnostics were right. Either self-denial or self-indulgence is the answer as long as one is in the physical world. There is no point for social action either, as that is an attempt to redeem the physical world.
It all goes because if the world is free from a fall, then there is no need to redeem the cosmos. There is nothing wrong with it. The gospel is just Plan B when you, as an individual, fail to be perfect, which you, in fact, can be. It's hard, but you can do it. And either way, the glory of God in your salvation is shared with you. There is no sense in the gospel message that says that no one is good, but God, that all have sinned and are deficient of the glory of God, that the heart/mind is sick above all things, etc. Only those who are sick need a physician, but how did we become sick when there was no disease? As I said before, Pelagianism begs a Gnostic cosmos while arguing that everything is actually good. There is no other explanation for universal evil, and of course, Pelagius' way out of this was simply to deny that universal evil existed. All men do not sin. There are others beside God who are good. If man's mind is sick, it is due to his own making.
Now, what I do find interesting is that, although Pelagianism is the theoretical route that many who deny a historical Adam are taking, the adoption of Darwinian evolution, which is why these people often deny a historical Adam in the first place, would lead one to a gnostic ontology, not a Pelagian one. We have these wayward sexual attractions because of our evolutionary biology. We rape, murder, betray, because it's a part of our biological makeup. Our problem is our physical biology and its evolutionary history.
The only way around that is to argue that people, even in their evolutionary makeup, are ontologically neutral or good, but that they have an inclination toward self-worship that they have inherited from their common ancestors.
Of course, when all is said and done, I'm not sure how a history of natural selection, where one has been violent and sexually deviant due to his ontology, can really be reconciled to the idea that man is created ontologically good, but becomes evil in terms of his estrangement from God's presence. I suppose one could chalk it up to being a mystery as to who that works out.
It may be possible to go to an Eastern Orthodox understanding of recapitulation and theosis in order to complete creation/salvation that one might view as having only started with the evolutionary process. Christ assumes humanity in order to redeem it by virtue of making it ontologically one with God. Christ has united the divinely good Spirit to deficient matter that is prone to evil in order to make what was prone to evil, and so Christ becomes the final step in our evolution.
But the problem in that is to say that God created imperfectly. He created a world filled with evil and suffering. It didn't become so through secondary agents, where he can use their deeds as secondary means to accomplish good. He is the primary agent of their sin. He made the world in such a way that when humans came to be they could not help but sin. It's a part of their deficient biological nature. Lady Gaga is right. They were "born this way." I'm not really guilty of my sin, then, because I couldn't have done otherwise. I have to sin. The one who is guilty for my sin is God who forced me, by virtue of my deficient nature, to sin. But this isn't the biblical picture of man's sin, and God's relation to it, at all.
Ironically, however, that flies in the face of Pelagianism and the argument that if God commands one to do good that implies he can do good. God is then just commanding him these things to show him that he cannot obey them, and needs a connection to the divine that overrides his biology in order to do so. So Christ came to complete human evolution by overriding its biological tendencies so that humans could finally obey God's commands, and by obeying those commands, he learns to live in Christ and gain his own salvation. Hence, when Christ said, "It is finished," He meant creation is finished. It's just the beginning of your quest to save yourself by now being able to obey God's commands. Rather than being a forgiveness of sins, one might say that this is a working off of your sins once you've been unified with Christ and have had your ontological deficiency "fixed."
I suppose one can believe that Christ does this AND forgives sins so that you don't have to work for it, so I don't want to create a false dilemma; but if the source of spiritual corruption is physical deficiency, then once that is taken care of on the cross, and we are unified with Christ, and given the Holy Spirit, we shouldn't sin anymore. If we must be resurrected in order to sin no more in the body, then there must be more to the source of our sin than our biology, but what would that be that would affect all of mankind without exception, as the Bible argues?
What a mess. All because of the unnecessary rejection of Adam and the historical fall. I'll continue to think through these things, but surely this is an awful lot of mental gymnastics to try and reconcile a rejection of a historidcal Adam and the fall that may not be necessary to reject in the first place just because one adopts evolution as a means through which God may have created.