Book review: “The Genealogical Adam & Eve” by S. Joshua Swamidass

Are science and religion compatible with one another?  More specifically:  Can one accept the scientific fact that human beings are the result of the 4 billion year process of evolution in which we share common ancestry with all other organisms that inhabit the earth, and at the same time believe the Biblical and Quranic accounts according to which we are all descended from a single couple who were directly created by God?  For many the answer is an unequivocal “No”.   This includes the members of creationist organizations such as Answers in Genesis, the Institute for Creation Research and the Discovery Institute who try to discredit the theory of evolution in favour of the belief that humans are a special creation of God.  On the other side are atheist scientists such as Richard Dawkins, Jerry Coyne and PZ Myers who argue that acceptance of scientific ideas  like evolution renders belief in God untenable. 

However, there remains a number of people who take an in-between position.  In fact, I suspect a majority of people, professional scientists and laypersons alike, simply hold to their religious beliefs (or lack thereof) with little or no thought given to how these relate to the scientific principles which they accept.  But there exist a group of people, often referred to as theistic evolutionists or evolutionary creationists, who are equally as devoted to theism as they are to science and actively work to create a reconciliation between the two. 

One such person is Dr. S. Joshua Swamidass.  I have earlier discussed his attempts to reconcile his belief in a literal Adam and Eve with his acceptance of mainstream evolutionary theory.  However, since I wrote that article he has published a book entitled The Genealogical Adam and Eve: The Surprising Science of Universal Ancestry in which he discusses his position in more detail. That position starts from two initial premises:

1)  We share ancestry with every other organism on earth, and our species arose from a common ancestor we share with chimpanzees about 6 million years ago, as described by the theory of evolution.

2) Adam and Eve were real people whose story is accurately described in Genesis.  They were directly created by God, Adam from the dust of the ground and Eve from Adam’s rib, and they resided in a garden in which they were the sole human inhabitants.  Moreover, they are ancestors of all humans now inhabit the earth.

Now, Swamidass does not attempt to provide evidence or argument to support either of these premises.  Rather, his goal is simply for the reader to entertain both premises as possibilities and then follow him as he attempts to argue that these premises at least could be true and, moreover, are compatible with one another, as unlikely as that may seem at first.

In order to follow his argument, one must understand the difference between genetic ancestry and genealogical ancestry.  Your children, if you have any, are your genetic as well your genealogical descendants.  In terms of genetic ancestry, your children will each have inherited about half of their DNA from you.  Your grandchildren, however, will have inherited only a quarter of their DNA from you, your great-grandchildren an eighth, and so on.  It is not difficult to realize that, after not too many generations, none of the people who are your descendants are likely to have inherited any of their DNA from you at all.  You would be what is called a “genetic ghost”.

However, you will remain a genealogical ancestor of all these people, regardless of whether you are their genetic ancestor.  And it is genealogical ancestry that Swamidass is referring to when he says that Adam and Eve are ancestors to everyone alive today.  He also emphasizes that genealogical, but not genetic, ancestry is an important concern in the Bible, as shown by the lengthy strings of “begat’s” that often describe the lineage of important figures. 

The other important scientific point that pertains to Swamidass’s argument is that of universal genealogical ancestry.  Imagine that we were to trace the family trees of every person now alive on earth backwards in time.  We would  eventually arrive at an individual who is present in every single tree.  This is the most recent common ancestor (MRCA) of everyone now alive.  It is important to understand that there is not necessarily anything about this person that would have been noticeably special at the time of this person’s existence to indicate he (or she) would become the MRCA.  Nor did the MRCA exist at a time when there were only two people alive on earth.  The MRCA just happened, by pure luck, to have left a large (and still growing) number of ancestors behind him.  But even in this regard he is not unique.  Just by virtue of being the most recent common ancestor does not mean he is the only common ancestor.  There are, in fact, countless individuals who lived before the MRCA that are also ancestors of us all.  In fact, for only a relatively short period of time prior to the existence of the MRCA is it possible for someone to be the ancestor of some, but not all, people alive today.  Prior to that, genealogical ancestry is an all or none proposition: If a person is ancestor of someone living today, he is ancestor of us all.  But if there is even one person alive today who is not his descendant, then no one is.  The point of all this, in terms of Swamidass’s model, is that there are many, many people who are universal genealogical ancestors of everyone alive today, so there is nothing surprising in Adam and Eve being among these, provided they lived long enough ago in the past to have existed prior to the MRCA.

And how long ago would that be?  The answer to that question is surprising and is the subject of what many readers may find the most interesting and informative section of the book.  A paper by Joseph T. Chang ¹ published in 1999 performed a statistical analysis of the human genome and concluded that the MRCA of all humans could have lived as recently as 700 years ago.  Subsequent research using more sophisticated modelling has pushed that date further back², but it remains likely that the MRCA lived in only the last few thousand years.

So with that in mind, here is the scenario that Swamidass proposes:  Our species arose thru the process of evolution as understood by standard, secular science.  However, at some point between the origin of the first organisms biologically identifiable as “human” (not necessarily Homo sapiens) and the MRCA of all humans who were alive in the year 1 CE, God created a pair of humans, male and female, with the intention that they would reside in a garden somewhere on earth (Swamidass believes it was likely located in the Middle East).  These two people were biologically indistinguishable from the human beings who lived outside the garden, and were therefore able to interbreed with them.  After Adam and Eve were expelled from the garden, their descendants did just that, such that Adam and Eve ended up among the humans who are universal genealogical ancestors of us all.

Swamidass emphasizes that such a scenario would leave no genomic or other physical evidence that two of our ancestors did not, themselves, share common ancestry with us, but instead had been created specially by God.  His position is that “science is silent” on this question.  However, he does believe there are theological implications.  Among these are the fact that we are mortal (if Adam and Eve had not eaten from the Tree of Life, we would live forever), that we are not morally perfect, and that we all are born with a debt to God that we cannot repay (except through acceptance of the sacrifice of Jesus Christ),  because God could have justly killed Adam and Eve for their transgression instead of allowing them to live outside the Garden of Eden. (The book makes little attempt to provide a detailed discussion of the theological reasoning behind these claims and Swamidass is careful to say he is not firmly committed to them. )

Overall, the book is clearly written and a reader with even a limited background in the relevant science should have no problem following its argument.  I was already familiar with the evidence regarding the date of our most recent genealogical ancestor from Richard Dawkins’s The Ancestor’s Tale  (which, if it was not already apparent, should confirm that this finding, in and of itself, does not provide evidence for the Biblical account of human origins.)  However, for someone not familiar with this research the discussion here will prove illuminating.  Personally, I was intrigued by the historical discussion of the theological debate that accompanied the scientific debate over whether the human species is polyphyletic or monophyletic ³, and the responses from European theologians to the discovery of previously unknown human civilizations in the New World and elsewhere, regarding where these people fit in terms of the Christian narrative of original sin and redemption. The author also does not shy away from acknowledging the racism that was often inherent in these debates, from scientists as well as from religious leaders.

However, as I stated in my earlier article, I remain unconvinced that Swamidass’s model is wholly consistent and coherent.  There was a moment in reading this book that I was jarred by its sudden change in approach.  One chapter discusses an important factor in the calculation of when the MRCA could have lived, namely the possibility of the existence of pockets of the human population that are isolated from the rest.  A prominent example is the island of Tasmania.  If its inhabitants had had no contact with anyone from off the island for, say, 50,000 years, then that would put an absolute limit on how recently the MRCA could have lived.  Swamidass goes thru a detailed and rigorous discussion of whether such isolation could have occurred, including whether it was possible that the island could have been visited by sailors from other areas, and how often this would have had to occur to move the date of the MRCA forward in time.

But the beginning of the chapter immediately following this discussion includes the bald statement that “There is no evidence against the de novo creation of Adam”, by which he means the creation of Adam from dust by God.  To me, that is a very bizarre statement to make.  Of course, there is scientific evidence against this claim.  That evidence is the simple observation that humans do not suddenly spring into existence from dust.  Swamidass believes he can justify this claim because if God exists then such miracles are possible.  But, if this is the case, then God could also have teleported a descendant of Adam and  Eve to Tasmania to impregnate a woman there, and thereby ensure that all Tasmanians are also descendants of Adam and Eve.  Swamidass does not entertain such possibilities because his model entails that no further miraculous interventions by God occur after the creation of Adam and Eve within the human lineage (other than the virgin birth of Jesus, of course.) While it is true that the Genesis story of Adam and Eve could be true without leaving any evidence in our genome, the same is true of the Greek myth of Zeus seducing and impregnating Leda by transforming himself into a swan, to pick just one example.  That “science is silent” on a story is no strong reason to believe the story is true. 

So the degree to which this book can be considered a success depends on how ambitious are its objectives.   If Swamidass’s intended audience is chiefly those who share his position of accepting both evolution and the traditional Biblical account of Adam and Eve, then this book is likely to be valuable in providing a model by which these two beliefs can be reconciled.  But statements in the book and elsewhere suggest he is interested in provoking a wider discussion, and there I am not sure how well he succeeds.  Assuming I am typical of most who consider the story of Adam and Eve to be nothing more, nor less, than one of the seminal myths of Western culture, nothing in this book convinces me that the story should instead be considered an historic description of events that actually transpired.  The absence of evidence in our genome is not a determining factor in my lack of belief in Adam and Eve.

What about creationists?  If the view of Adam and Eve as our genealogical ancestors can be reconciled with the evolutionary account of human origins, will this persuade them to recognize and accept that the theory of evolution cannot be reasonably denied?  Of that I am not very hopeful.  From years of debating and interacting with creationists of all stripes, I can testify to the tenacity of their resistance to understanding and accepting scientific evidence that conctradicts their faith. That faith usually entails that human beings can only exist if created by God.  Such people are not going to be much tempted by any model that requires them to accept their common ancestry with a chimpanzee, even it allows them to also claim a couple ancestors who were miraculously brought to life by God. 

As I wrote in my earlier article:

In an odd sense, it could be argued that Swamidass actually shows less respect and deference to science than does a Young Earth Creationist like Ken Ham or an Intelligent Design Creationist like Michael Behe (Though, I hasten to add, in every other respect his understanding and acceptance of science far exceeds theirs). What these two have in common is the position that the current scientific consensus is seriously wrong on the question of human origins and that, if properly understood, the scientific evidence would show that no human beings could have evolved from non-human organisms without the direct intervention of a god…. They believe the theory of evolution is thereby falsified on scientific grounds. The YEC’s and the IDC’s… endeavour to create a better science to replace the current science which (they claim) has been corrupted by scientists’ embrace of materialism and secularism, if not outright atheism. Swamidass, on the other hand, seeks to circumscribe science and install a firewall between it and religion, such that each discipline works in relative isolation from each other. As such, I do not see his scenario holding much attraction for creationists of various stripes whose true ambition is to bring science to heel and make it subservient to scriptural revelation.

My personal position is that there is neither good evidence nor good reason to consider our world to be one in which the miraculous and “supernatural” exist alongside the things we know to exist and occur through the empirical evidence available to our senses.  The ingenuity and scientific rigour Swamidass brings to his argument is not sufficient to make me reconsider that position.  Will it persuade creationists to reconsider their position? While I am doubtful, I hope it will.  And I commend S. Joshua Swamidass for trying.  

1. Chang JT. (1999). Recent common ancestors of all present-day individuals. Advances in Applied Probability 31:4., 1002-1036.
2. Rohde DL, Olson S, Chang JT. (2004) Modelling the recent common ancestry of all living humans. Nature Sep 30;431(7008):562-6.
3. Swamidass has since issued a correction of some his comments on this subject: https://peacefulscience.org/wrong-on-monophyletic/