The responses are, as I anticipated, beginning to come in on my post on the controversy over Adam and Eve, which was spawned by New Atheist biologist Jerry Coyne's claim that "[T]he genetic data show unequivocally that humanity did not descend from a single pair that lived in the genus Homo."
There were several responses from Christian thinkers to this claim, but, as is becoming increasingly common, the most telling came from Catholic philosopher Ed Feser, someone who we have had multiple opportunities on this blog to cheer on. Feser is an Aristotelian Thomist, which just means that he subscribes to the version of Aristotelian philosophy articulated most comprehensively by the medieval philosopher St. Thomas Aquinas in the 13th century. As I have said before, Thomas' thought is the only thing worthy to be called Christian philosophy and all other pretenders to that title are weak imitations.
In the present case, Feser has applied the traditional Aristotelian Thomist definition of a "human being," which consists simply of the belief that man is a rational animal. We can explain this by using the terms laid out by Porphyry, a 3rd century Neoplatonist philosopher, in this famous "Porphyrean Tree," a division of all substance.
According to Porphyry, who was simply riffing on what Aristotle had said a few centuries earlier, man, in the most general terms, is an "animal" in the sense that, along with the beasts, he is a sentient, living, material substance. An animal is a living material organism that has senses--unlike plants which are non-sentient living, material substances; and unlike rocks, which are non-living material substances; and unlike angels, which are non-material substances. A man is an animal in this sense, but he has a specific difference that marks him off from the animal (which in traditional logic is called the "specific difference"), which is the quality of rationality itself. This makes him the only being who is a rational sentient, living, material substance.
The Christian belief, based on the Scriptural revelation, is that the human race, consisting of these rational animals, began with two people: Adam and Eve. And we are all descended ultimately from this pair. Genesis says this and the Apostle Paul, whose epistles are an important part of the Divine Revelation, clearly assumes this. In addition, the disobedient actions of this pair caused a spiritual rupture between them and God, and this separated status is shared by all their descendants by virtue of their sharing in the same human nature.
This is the doctrine of original sin. And just as Adam represents the human race in rebelling against God, so Christ represents it on the cross in redeeming it. This, of course, is one of the reasons the doctrine is so important: man is redeemed in the same way he fell: according to a representational scheme: Adam represented man in the fall in the same way Christ represented man in the redemption. Paul states this pretty clearly in Romans. So if you believe Christ redeemed the human race in the act of crucifixion and resurrection, you shouldn't have any problem believing that Adam brought it down in the act of disobedience. They're sort of two sides of the same coin.
A number of scientists (including Christian ones) say that, over the course of the evolution of human beings, there was never just two humans: at the smallest bottleneck of the developmental chain, there were, at minimum, at least 10,000 individuals. Therefore, they say, we are not descended from one primordial pair.
Now there are undoubtedly numerous assumptions along the chain of reasoning that leads to this 10,000 individual estimate. And it is a little suspicious that others use other numbers, which would seem to indicate that this is, in some respect, and inexact science. And obviously there is the evolutionary assumption as well, and there are not a few Christians who won't go for that. But for purposes of addressing the question of whether there was an Adam and Eve whose descendants we are, it really doesn't matter. We can stipulate this for purposes of debate.
One of the interesting things about this debate is that, before Feser weighed in, a number of Christian thinkers, unarmed by the Thomistic distinctions, tried to deal with the implications of the genetic evidence, but, quite frankly, didn't do a very good job of it. Without a proper definition of human being, these people, well-intentioned as I'm sure they were, were in the position of either having to argue against the evidence of genetics on the one hand, or rejecting the traditional account of the Biblical Adam and Eve story on the other. The ones getting the press, of course, took the latter course.
Feser simply pointed out that the term "human being" is not merely a biological designation, but a metaphysical one as well. He is a rational animal--and the "rational" part of that is not a biological designation. Unfortunately, many of the evangelical rationalizations--like that of Fracis Collins--bought into the idea that man is only his biology.
If you don't understand what man is, then your going to have a heck of a time determining who the first one is.