These first true human beings also have descendants, which continue, to some extent, to interbreed with the non-intellectual hominids among whom they live. If God endows each individual that has even a single [metaphysically] human ancestor with an intellect of its own, a reasonable rate of reproductive success and a reasonable selective advantage would easily replace a non-intellectual hominid population of 5,000 individuals with a philosophically (and, if the two concepts are extensionally equivalent, theologically) human population within three centuries. Throughout this process, all theologically human beings would be descended from a single original human couple (in the sense of having that human couple among their ancestors) without there ever having been a population bottleneck in the human species.
So there is no problem of reconciling the claims in question. On the scenario proposed, the modern human population has the genes it has because it is descended from a group of several thousand individuals, only two of whom had immaterial souls. But only those later individuals who had this pair among their ancestors (even if they also had as ancestors members of the original group which did not have immaterial souls) have descendents living today. In that sense, every modern human is both descended from an original population of several thousand and from an original pair. There is no contradiction because the claim that modern humans are descended from an original pair does not entail that they received all their genes from that pair alone. As Flynn points out, critics like Jerry Coyne confuse the claim that there is one man from whom all modern humans are descended -- a claim that is part of the doctrine of original sin -- with the claim that all modern humans are descended from only one man -- a claim which need not be understood as part of the doctrine. And as Flynn also points out, it is arguably only the male of the pair, and not the couple, that the doctrine requires all modern humans to be descended from.
Now, recall that this whole blogospheric debate got started because Coyne boldly proclaimed that “we can dismiss a physical Adam and Eve with near scientific certainty” but also professed interest in hearing “the best way to reconcile the Biblical story of Adam and Eve with the genetic facts” (even offering as a prize for the best answer an autographed copy of his book Why Evolution is True). So, now that he’s got his answer, what does Coyne do? He completely misses the point. In response to my recent post, Coyne writes:
As I noted in my previous post, what Catholic theology requires is that all humans living today have Adam as an ancestor, and that Adam’s soul was infused directly by God. It does not require that Adam was literally made directly from dust or clay. And though Rosenhouse is correct that Genesis is interested in the formation of Adam’s body and not merely the origin of his soul, that too is consistent with the Flynn/Kemp account if we think of the matter God used to form that body as derived from pre-existing hominids rather than straight from the earth. I know Rosenhouse, Coyne, and Co. would like it to be the case that all Christians are crude literalists --after all, that would facilitate atheist combox smart-assery and other forms of Serious Thinking. But it just isn’t so. As a matter of fact, the most traditional Christians are not crude literalists. As Mike Flynn emphasizes in his post, that the literal and figurative senses of statements in the book of Genesis must be carefully distinguished is a long-standing theme in traditional biblical exegesis, and was famously explored by St. Augustine. Flynn writes: