1. Background of the Issue
In accounts of the origin of the world, perhaps no aspect is of more interest—at least to us, who are the only species capable of understanding those accounts—than the origin of the human race. I hope within a year or so to complete a book on the history of “Catholic evolutionism,” that is, on the attempts to reconcile the central ideas of biological evolution and Catholic theology. As that history shows, there were two issues of particular concern to theologians, both of which focused on man.
The first issue concerned the origin of the human body. Genesis 2:6 seemed to say to many theologians that God formed the first human body directly from dust. The most developed Catholic alternative was offered by English biologist St. George Mivart (1827-1900). According to his On the Genesis of Species, the first human being was the product of the infusion of a divinely created soul into an evolved body. His idea gradually spread and, despite the determined resistance of its theological opponents, the question was explicitly recognized as open in Pius XII’s encyclical Humani generis (§35-37).
Of greater theological concern, however, was the second issue regarding human origins, namely the question of “Adam and Eve” and “Original Sin.” Traditional Catholic doctrine, the proximate source of which was the “Decree Concerning Original Sin” (§3)produced by the Council of Trent in 1546, taught that human sinfulness (peccatum originale originatum) was the result of an original sin (peccatum originale originans), committed by the first human beings and inherited by all other human beings. That seemed, said Humani generis, to require that the human race originated in a single place and with exactly one couple (“monogenism”). The strict monogenism of the Catholic view did not go unchallenged, however.
Even long before the issuance of the encyclical, some critics argued that the human race could not have originated in a single place. This idea has appeared in various forms under various names: “Pre-Adamitism” (Isaac de La Peyrère and Alexander Winchell); “polygenism” (Josiah Clark Nott and George Robin Glidden); and “polyphyletism” (Ernst Haeckel). Some of its proponents (Nott and Gliddon, Haeckel, Karl Vogt) added to it the idea that there were multiple distinct human species, whereas others (La Peyrère, and sometimes Louis Agassiz) denied this. Some were evolutionists (Haeckel, Vogt), whereas others (Agassiz) were not. Some of its defenders (Nott and Gliddon) argued that multiplicity of geographical origin was not consistent with Christian doctrine; others (Agassiz) argued that it was.
A second line of criticism accepted the existence of what Darwin called a “single center of creation” for each species, including man, but argued that these centers of origin hosted not just a single first couple, but an entire initial population. Ernst Haeckel said that the idea of there being a first human being was as strange as would be the idea that there was a first Englishman. Moreover, a single center of origin did not guarantee a single human species (“specific unity”), since it did not preclude the human race, after its origination, splitting into several species (“cladogenetic speciation”). So, while Darwin and Huxley defended the idea of a single human species, other generally-Darwinian scientists (e.g. Haeckel) did not.
The Darwinian answer to the numbers questions—namely, a numerous initial population in a single location—was reinforced, in particular with regard to human origins, by developments in genetics. Once scientists were able to compare distinct alleles across species, they noticed that the diversity found at certain loci in the human genome corresponded to a similar diversity found in chimpanzees. The variation must have originated before these lineages split and was too great to have passed through a phylogenetic bottleneck as narrow as a single couple. These results were presented by Francisco Ayala to the American Catholic bishops in 1998.
The encyclical Humani generis, to be clear, had not been definitive about the incompatibility of polygenism (in the sense of a numerous initial human population, rather than a single couple) and the traditional understanding of original sin. It had said only that it was by no means clear how the two could be reconciled. Archival materials on the drafting of the encyclical were opened to researchers on March 2, 2020, and I was able to review these documents in the week before the imposition of a general curfew made continued work impossible. The archival records make clear that the non-definitive language was deliberately chosen over the stronger language of early drafts of the encyclical.
There have been various attempts by Catholic theologians, in the seventy years since the publication of Humani generis, to find some way to reconcile polygenism with the traditional understanding of original sin. Indeed, in 2004, the International Theological Commission prepared a document (ultimately issued by the Congregation for the Doctrine of the Faith) that referred to “the emergence of the first members of the human species (whether as individuals or in populations).” Nevertheless, other authoritative documents, in particular the Catechism of the Catholic Church (1994) present the Fall in a fairly traditional way.
It was this apparent tension between science and the more traditional theological account of the origin of the human race that I attempted to resolve in an article I published in 2011. Building on some work by Josephite priest Andrew Alexander (“Human Origins and Genetics” [Clergy Review 49: 1964]), and applying the adage, “When faced with a contradiction, make a distinction,” I suggested this possible account of the origin of the human race:
Evolution of a population of primates sufficiently large to carry the genetic diversity in question and with cognitive development sufficient to allow the infusion of a rational soul.
Transformation of two of those primates into rational and, therefore, “fully human” beings by infusion of a created rational soul without destruction of their reproductive compatibility with the primate population out of which they were selected. At that point, there would have existed both “fully human” (i.e., rational) beings and “merely biologically human” beings.
Interbreeding between the fully human beings and their merely biologically human neighbors.
Creation of rational souls for each of the descendants of every fully human being (Strictly, “for many of the descendants” is all that is necessary).
In that scenario, there would be no genetic bottleneck of the kind which geneticists say never existed. In addition, it seemed to me, within a reasonable amount of time every living biologically human being would have among its ancestors the first couple of fully human beings, and would also themselves be fully human. Consequently, in accord with experience, there would be no “merely biological humans” walking around today. And, in accord with traditional Catholic teaching, every fully human being who ever lived would be a descendant of the first fully human couple.
That would dissolve the apparent contradiction. The idea received favorable notice. Still, there were questions that might be asked that I had not been able to answer. How long would it take until all biologically human beings were also theologically human? Would full humanity be able to spread to the ends of the earth, even to long-isolated populations, such as in Tasmania? How long ago would our first parents have to have lived in order to make it plausible that every human being (including any prehistoric hominins that show signs of rationality) would be descended from them? How recent could they have been?
I was happy to hear last year that S. Joshua Swamidass had, in The Genealogical Adam and Eve, offered scientific answers to some of those questions. Swamidass is a Washington University biologist and an Evangelical Protestant. Raised as “a young earth creationist … following a literalistic interpretation of Genesis,” he was also “drawn to science” and was determined to “resolve the conflicts between these two accounts” (p. 7).
2. The Contribution of Swamidass’s New Book
In his new book, Genealogical Adam and Eve: The Surprising Science of Universal Ancestry, Swamidass does two things. First, building on the work of others, he offered scientific answers to some of questions which I had not been able to answer in any detail. Second, he offered a narrative of the origin of the human race that differs in some important respects from my own, and which, moreover, is not in all respects compatible with Catholic doctrine. I will begin by discussing the very important contributions that he makes to the question. Then I will go on to express some concerns and objections that I have. Some of those are based on Catholic doctrine, others just on my own judgment about the matters in question.
Swamidass begins by offering “a speculative narrative of origins contain[ing] the traditional de novo account of Adam and Eve alongside evolutionary science” (13). Science, he says, shows both that man originates in an entire population (with no bottleneck) and that man and apes have ancestors in common. The “traditional account” of Adam and Eve, he says, is that “Adam and Eve were real people, who:
- lived in the Middle East, just several thousand years ago,
- were the ancestors of everyone, and
- were created, with no parents, by a direct act of God (5).
Swamidass argues, as I did, that if the descendants of Adam and Eve interbred with a larger population, both the scientific and a traditional religious account could be true. Of course, Swamidass’s formulation of the traditional account includes points that many Catholics would no longer include (such as Adam and Eve having no parents, and their living in the Middle East just a few thousand years ago), but none of those additional points affects the possibility of combining other parts of his work with more standard Catholic formulations.
He was able to offer scientific arguments for important points that I was only able to suggest. Three conclusions vary from what one might at first expect:
(1) universal ancestors arise recently in our past, (2) this finding is robust, not tightly dependent on any strong assumptions, and (3) universal ancestors are common, arising everywhere (46).
How recently? There are people who lived as recently as a few thousand years ago who are ancestors of everyone who is alive today (42). Indeed, one can also calculate an “identical ancestor point” where “everyone at that point and more ancient is either ancestor of everyone alive today or ancestor of no one.” A fourth conclusion, that most of them are “genetic ghosts,” who left “no evidence of their existence in our genomes” (46), is also worth noting, since Swamidass comments that “Adam and Eve are most likely genetic ghosts that pass us no DNA” (84). If they really were genetic ghosts, that fact would complicate an old Catholic proposal first suggested (though not explicitly defended) by Zeferino Cardinal González in 1892, namely divine modification of an evolved animal body. Presumably, such a modification would have to be passed on to many (if not all) of the descendants of Adam if it is to do the theological work required of it. There are, however, perhaps complex ways of reconciling the two ideas.
Swamidass’s results permit dates recent enough to satisfy even those who take the Genesis chronologies relatively literally, but that only shows how recently universal common ancestors could have lived, not how recently they must have lived; they do not rule out, for example, a pre-Cro-Magnon Adam.
3. An Objection: The Nature of the “People Outside the Garden”
Despite my appreciation of the contribution which he has made to the topic, I do have two lines of concern about the book. One is about some terminological (but not merely verbal) matters as well as some associated historical questions. The core of the book, as I indicated above, seems to me to be sound and to make an important contribution to the topic. He does, however, go on to elaborate his view in ways that call for separate comment. None of the details of the elaboration are central to what I think are the most important contributions of the book, discussed above.
His speculative narrative differs from mine in one particularly important respect, namely the nature of the individuals in the larger population within which Adam and Eve lived and with which their offspring interbred. In my 2011 article, although I acknowledged that the step beyond merely biological humanity could be made either on philosophical or on theological grounds (i.e., on the basis either that human beings have rational powers or that they have some distinctive relation to God), I meant to minimize the difference between those grounds, suggesting that Adam and Eve had both features while the merely biologically human beings, by contrast, had neither.
That did, to be sure, leaves my account vulnerable to the charge that the interbreeding between the “fully human beings” and the “merely biologically human beings,” which was central to my thesis, constituted bestiality. The sexual relations in question were with beings that looked like and were reproductively compatible with fully human beings but were not rational. Such relations would be impersonal, to be sure, but that would make them more like casual sexual acts than like bestial ones. The objection of “bestiality” is what, in prosecutorial practice, is called “overcharging.” In any case, sexual relations between fully human and merely biologically human beings was not necessarily part of the divine plan for the human race. Perhaps the original plan, aborted after the Fall, included the later infusion of rational souls into other members of the original population of biological humans?
Swamidass develops a different scenario, which avoids the bestiality objection but, as we will see, at considerable theological cost. Swamidass divides the relevant population somewhat differently. His fundamental distinction is between Adam and Eve (who are “inside the Garden”) and their descendants, on the one hand, and “people outside the Garden,” i.e., the other biologically human beings with whom they interbred. These are “fully human,” at least “in important ways” (149), though his terminology is a bit unsettled, for elsewhere he suggests that they not be called “humans” (rather than just “people”) outside the Garden (134).
This allows him to avoid the idea that fully human beings interbred with merely biologically human beings (i.e., with what are really only animals). To avoid this, however, would require assuming that those “outside the Garden” were philosophically human. And since these were not descended from Adam, they could not have original sin either by personal act or by inheritance. Catholic doctrine, however, holds that all philosophically human beings who ever lived have original sin, with only two exceptions: Jesus and Mary. The usual Protestant objection to Catholicism on this point is that Catholics make one-too-many exceptions (namely Mary) to the otherwise universal guilt of original sin. Swamidass, however, though a Protestant, gives us a whole tribe more of such exceptions. There are, it seems to me, two important respects in which Swamidass’s account is inconsistent with Catholic theology. The first is with respect to its anthropology, the second is with respect to the nature of sin.
Leaving theology aside for the moment . . . what makes a being “fully human”? I think that the answer is its rational powers (reason and free will), or, equivalently, possession of a rational soul (each of which, individually, has to be created by God). Swamidass says that “the image of God . . . and ‘rational souls’ might arise much earlier than Adam” (171, 178). If that was the case, what would those earlier people have lacked that made them less than “true men”? What makes a being a true man has to be its nature, not (as Swamidass apparently would have it) just its vocation or history. His view, it seems to me, does not succeed in avoiding the idea that there were “true men who did not take their origin through natural generation from Adam,” which would make it inconsistent with the Catholic account presented in Humani generis (§37).
Second, the distinction between the wrongdoing of those rational beings and the sin of Adam is unclear. They did wrong, Swamidass says, though their sins were of a sort different from Adam’s (182). It may be that we can make a conceptual distinction (as Swamidass does, 189) between “imputation of debt” and “moral corruption;” but original sin (peccatum originale origanatum) is more than the former and, if “moral corruption” means actually having sinned, not equivalent to the latter. It is a dispositional property (like fragility). To say that a newborn baby has original sin is not just to say that it owes a debt due to Adam’s sin, but also that, if it reaches the age of reason, it will commit sins. Swamidass’s book also takes up a number of other matters, some primarily of theological interest. I will mention here two questions that seem to me to be more closely related to scientific matters than some of the others.
First, when did Adam and Eve live? Swamidass emphasizes that genealogical considerations allow a surprisingly late date. Universal common ancestors of all human beings alive at the time of Christ could have lived as recently as about 10,000 years ago. He recognizes that Adam and Eve need not be our most recent universal common ancestors. For the reasons given above, however, Catholic theology will be guided here not merely by genealogical issues, but by evidence of rational behavior. Adam and Eve must be the ancestors of all rational human beings on earth with any biological relation to us.
Second, did the first human beings lack biological parents, their bodies being formed by direct divine action (from dust, or from a rib)? The controversy over whether Adam’s body was formed from the dust of the earth had a long run in Catholic theology, with repeated attempts on the part of the immediate-formationists to suppress the work of their evolutionist rivals. They achieved limited institutional success in the case of Dalmace Leroy and John Zahm at the end of the nineteenth century (see: Negotiating Darwin), but not in the case of Henry de Dorlodot, E. H. Messenger, or later authors. That controversy died down in the wake of the official tolerance of evolutionism (about human bodies) in Humani generis and is no longer a feature of most Catholic discussion of the question, where an evolutionary origin of the human body is taken for granted. Swamidass points out that it would by no means be impossible for God to form from dust a body like the evolved bodies of beings already in existence. Indeed, if God intended for them to interbreed with those other beings, the bodies of Adam and Eve would have to be like the bodies already in existence. In this, he is surely correct, a consolation for formationists, but not an option congenial to those, like Catholics, who think that God makes use of the natural processes which he has already established when they are available for the task at hand.
Catholics interested in the question of the historical reality of Adam and Eve should definitely read this book. It makes some important new contributions to the subject that are entirely consistent with Catholic orthodoxy. There are, to be sure, also parts of the book that address questions that (rightly, I think) have not been of particular concern to Catholics, at least not in the last hundred years, and parts where Swamidass proposes ideas that, it seems to me, contradict relatively authoritative (though perhaps not unrevisable) Catholic teaching. Passages of these latter two types are, however, severable (to use the legal term) from the contributions he makes to the resolution of this putative conflict between science and theology.
EDITORIAL NOTE: This article is part of a collaboration with the Society of Catholic Scientists (click here to read about becoming a member). You can ask questions and join a wider discussion of the above essay at the bottom of this page where the original longer version, which includes an extensive appendix, of it is published.