I’m still waiting for someone to explain how this version of Adam, dropped into the flow of history 6,000 years ago, has anything to do with sin or original sin. The problem is even more acute if one insists that sin can only be defined as the breaking of a revealed command. That would mean sin did not exist before 4,000 B.C. Follow out this line of reasoning …
And what does the “knowledge of good and evil” mean in the context of this ad hoc Adam? In Deut. 1:39 and Is. 7:15-16 it is used of children, who do not yet know to choose good and reject evil. Surely, we aren’t expected to think that men before 4000 B.C. lacked moral knowledge, are we?
The only advantage I can see to the ad hoc Adam is that he is completely insulated from attack by science or history. The disadvantages are still piling up …