In this series, we explore the genetic evidence that indicates humans became a separate species as a substantial population, rather than descending uniquely from an ancestral pair.
When the RMS Titanic sank in April of 1912, the tragic circumstances of one family made headlines. Canadians Hudson and Bess Allison, along with their two-year-old daughter Loraine, infant son Trevor, and various servants, were first class passengers – and as such Bess and the children had ready access to the lifeboats. In the chaos, however, things went awry: Trevor was borne to safety in a lifeboat by his nurse, likely with Hudson and Bess unaware. While it is not certain, it is likely that Bess and Loraine remained with Hudson in the ensuing search for Trevor until it was too late: Hudson, Bess and Loraine went down with the ship, and only Hudson’s body was recovered. Bess was one of only a handful of women in first class to perish; Loraine was the only child in first or second class to do so, leaving her infant brother as the sole surviving member of the family. Tragically, he too would die at the age of eighteen, leaving the sizeable Allison estate to more distant relatives.
In 1940, however, an American woman named Helen Loraine Kramer came forward claiming to be the long lost Loraine Allison, and heir to the Allison family wealth. Her claims were rejected by the Allison family, and after a time she dropped out of the media limelight. It was not until 2012, the 100-year anniversary of the sinking, that Kramer’s claims would again surface – this time championed by her granddaughter, who also was seeking interviews and a book deal. In 2012 there was, of course an easy way to determine the truth of the matter that had not been available in 1940: DNA evidence. Since the claim involved a continuous line of female descent, mitochondrial DNA evidence was relevant. Though Kramer’s granddaughter did not submit a DNA sample, another female relative of Kramer was willing. A female relative of Bess Allison also provided a sample, keen to finally put the trying ordeal to rest. The resulting analysis demonstrated that Kramer’s mitochondrial DNA was not at all a match to that of Bess Allison, indicating that Kramer cannot be Loraine Allison. The case is thus closed, though Kramer’s granddaughter still maintains a website where she attempts to cast doubt on the results and promises forthcoming evidence in her favor.
We have been examining the arguments of Vern Poythress in his short book Did Adam Exist? – a book written to persuade Evangelicals that holding to a literal Adam and Eve as the specially created, sole genetic progenitors of the entire human race remains a credible option for Christian apologetics. As we have seen, Poythress’ scientific arguments have not withstood scrutiny. His final argument, however, is not scientific but rather theological in nature: that Christians should withhold judgment on human genetics because God may have employed miracles when creating the human race.
The argument in Did Adam Exist? takes the following form:
Now consider the second issue, the issue of gradualism. According to the picture in the Bible, God can work as he wishes. Many times he works through gradual processes, as we have observed. The regularity of these processes reflects God’s faithfulness. But he is not a prisoner underneath these processes. His rule over the world is what establishes the processes in the first place. He is free to work exceptionally, whenever he wishes. The experimental aspect of science is possible because of the regularities in God’s rule. But, rightly understood, science is subject to God and cannot presume to dictate to him what he has to do. It cannot forbid exceptions. Thus, exceptions are possible in the case of one-time, unrepeatable events, such as the origin of the universe, the origin of the first life, and the origin of human beings. The gradual processes that represent the usual means for God’s rule may have exceptions…
Matthew 1:18-25 and Luke 1:34-37 indicate that Jesus was born of a virgin. If a scientist had been able to test a sample of DNA from Jesus’ cells, would he have found a normal human Y chromosome, such as is present in the human DNA of men but not women? The Bible does not speak directly about such details, but Heb 2:14, 17; 4:15, and other passages indicate that Jesus was fully human. (Other passages, of course, indicate that he is also fully divine. He is one person with two natures, a divine nature and a human nature. This is a great mystery.) It is reasonable to infer that Jesus’ full humanity extended even to details like the Y chromosome. If so, the Y chromosome is an example of a thorough-going DNA match that was not the product of ordinary mammalian reproductive processes…
Jesus’ virgin birth is clearly a most exceptional case, but it shows that we must reckon with more than one possible account for DNA matches.
How might this argument apply to questions of our origins? In raising the possibility of miracles, Poythress is effectively claiming that no conclusion of genetics is sure, because there may be, unknown to us, the exceptional acts of God at play that render the evidence unintelligible to the methods of science. Taken to its logical conclusion, this argument would establish that no conclusion of science as a whole is sure – because, as Poythress would surely agree, the exceptional acts of God are not limited to genetics, but could in principle apply to any area of the natural world.
It should go without saying that I find this a puzzling, weak argument. I find it puzzling, because I know that Poythress does treat certain conclusions of science as settled, such as the evidence for an old earth. If God is free to work exceptionally in genetics, surely he is also free in geology, radiometric dating, cosmology, dendrochronology, and other fields that attest to the age of the earth. Yet Poythress does not argue for exceptions here (at least, not that I know of). Why does Poythress not do so? Because there is an overall pattern of evidence within those disciplines that point to the same conclusion (the earth is old), and to argue otherwise requires one to postulate that God is performing exceptional acts in an ad hoc manner to maintain a charade. It is formally possible, yes, that the earth is actually young and that God miraculously arranged the evidence, repeatedly, in such a way to give it an appearance of age – just as it is formally possible that God engineered the genomes of billions of people to give the unmistakable impression that we descend from a population of thousands and, further back, share ancestors with other species. But why would he do so? What possible end could it serve? While the Incarnation presumably required Jesus to have a Y chromosome, the patterns of DNA variation we observe in humans are not necessary. Perhaps some miraculous engineering of variation underlying our immune system might be explicable, but the vast majority of human DNA variation has no biological relevance – we’d all be fine being much more similar to each other than we are. Genetic diseases aside, most genetic variants in humans are neutral in their effects.
Taken to its logical conclusion, Poythress’s argument means it is not appropriate for geneticists to settle paternity disputes, use DNA evidence to solve murders, seek causes or treatments for genetic diseases, or investigate 75-year-old cases of fraud – because there is no necessary reason to suppose that what we observe is in fact the result of God sustaining natural genetic processes. Surely Poythress would not accept an appeal to miracle to explain away DNA evidence in the courtroom, yet that is the equivalent (and more) of what he asks of geneticists in the service of his apologetic.
In the next post in this series, we’ll turn to the arguments of a second apologist as they pertain to Adam and Eve: those of Dr. William Lane Craig.