Tell a Catholic kid about evolution—that there was a Big Bang and that in this expanding cosmos our sun is a star in a cluster of 200 billion stars in the arm of a spiral in a galaxy among thousands, and that eventually on our planet there appeared early life forms, single-celled bacteria, trilobites, mollusks, fish, amphibians, reptiles, birds, mammals, primates, and that from a common ape-like ancestor the Homo genus emerged, including Homo rudolfensis, Homo habilis, Homo erectus, Homo heidelbergensis, Homo floresiensis, Homo neanderthalensis, and last, Homo sapiens, or “wise man,” the hominin species that is modern human. The very next question that kid will ask is, “So where do Adam and Eve fit in?” (Ask me how I know!) It is a logical question.

Adults have varied reactions. Atheists tend to guffaw at the mention of those names in the same sentence as evolution. Fundamentalists propugn their version of dogma as if they are the sole authorities, disregarding science and any Magisterial documents they deem unacceptable. I remember feeling frustrated because I just wanted to know how to sort the question out without being ridiculed, scolded, or accused of heresy. Fortunately, this is not an either/or question. We do not have to pick between atheistic evolution and Young Earth Creationism. The Church does not teach those extremes at all.

The first thing to get straight is this: We do not know the exact biological details of Adam and Eve, and we never will. Once you understand that, it is easier to navigate the rest. An analogy is useful here.


Like Sand on a Beach

Suppose someone asks where two grains of sand “fit into” the history of a beach — not just any two grains, but the first two grains that ever existed on that beach. How do you answer such a question? Do you go get a John Deere excavator and start digging? Hopefully not, because there is no conceivable way a 1-cubic meter bucket could find two lone millimeter-sized particles of silica. Your response might be, “Hold it! Beaches do not form one grain of sand at a time!” And you would be correct. The erosion of rocks over time produces the sand which forms a beach as waves deposit sediment on the shore. Asking a scientific question about how to find the first two grains of sand on a beach is nonsense.

However, the lack of a scientific explanation does not rule out a miracle. God could have created two first grains in a space that would become a beach. The atoms and subatomic particles could even disperse over time. Science, and all its tools, could not find them though because (1) the scientific explanation for beach formation does not involve miracles, and (2) scientific methods cannot decipher the past successive production of individual sand particles.

Just like a beach, evolution occurs in events that can be described at the individual level but not determined as they happened historically. Generation by generation, parents begat offspring, offspring became parents who beget offspring, genetically alike yet genetically unique, and so on. Even so, we cannot know all the historical scientific details. There is a limit to the ability of evolutionary tools to resolve past successive events. Evolution is understood in terms of populations of thousands of organisms giving rise to new species over geological time. No evolutionary model implies a first pair of human individuals because no evolutionary model would. Why? There is no known species that arose by the sudden appearance of the first two parents.

Furthermore, even if the remains of the first man were found—imagine, for instance, Adam’s jawbone—no radiometric dating, genetic dating, nor any other analytical system could ascertain that the fossil came from the first man. Dating techniques rely on comparison. When a new specimen is found, it is compared to other samples that have been dated. Scientists have no way to know if the oldest generation found is the oldest generation ever to be found. The genetic molecular clock uses the rate at which molecular changes accumulate in successive generations to estimate evolutionary timing. These results, too, must be calibrated with the fossil record, and radiometric dating methods can only be resolved to geological timescales of thousands or millions of years for remote pasts. Hence, asking a scientific question about how to find the first parents of the human race is (like looking for grains of sand) nonsense.


A Remarkable Fact and a Unique Finding

Note however, Homo sapiens eventually spread throughout the planet and is the only surviving hominin species. That is a fact, and it is stunning when you stop and think about it. Humans filled the earth.

If we follow generations back far enough, conceptually we come to the most recent common ancestor — an individual who is a progenitor of all present-day people. Genealogical computation models suggest this ancestor lived around a few thousand years ago (Rohde, et. al., Nature, 2004). If we continue further back, we come to the first human population, thought to have lived some 50,000 to 200,000 years ago (Noonan, Genome Research, 2010).

A worldwide survey of human mitochondrial DNA using genetic molecular clocks has shown that all mitochondrial DNAs stem from one woman, known as Mitochondrial Eve, who lived about 200,000 years ago in Africa (Cann, et. al., Nature, 1987). Similar genetic studies suggest a Y-chromosome Adam lived roughly the same time (Francalacci, Science, 2013). These results do not conclude that there was only one woman or man living in the same place. They absolutely do not point to a monogenetic pair of parents. They only suggest that there may have been a “genetic bottleneck,” i.e. a time when a relatively small population of around 10,000 early humans lived. Rather than pointing to this conclusion as evidence against the existence of two first parents, I would rather say that this finding is consistent with a unique emergence of human beings. However, I am quick to add that such studies are provisional and ongoing, intended to calibrate and increase the resolution of the human phylogenetic tree. They neither prove nor disprove what we profess in faith.


The Limits of Knowledge

What lies between a population of 10,000 and 2 some 200,000 years ago? It is hidden to us. Some people opine that Adam and Eve did not literally live, that they represent a real story but not a literal one. Some people quote Humani Generis (37) on polygenism and leave it at that, but the document does not answer the question about how to figure Adam and Eve in the context of evolution. The encyclical was written in 1950 before genetics was understood. Pope Pius XII’s statement that it was “in no way apparent” how to reconcile evolution with divine revelation left a crack in a door that remains to be addressed. Will it someday be apparent?

Meanwhile, reason does not compel us to claim that Adam and Eve were figurative. I accept, and teach my children, that Adam and Eve really lived, and I teach them about the fall from grace and original sin. As I hope I have sufficiently explained in this essay, if Adam and Eve began to live—literally—as a grown man and woman through a miraculous act of God, science can only shrug and keep on digging. Evolutionary biology has no say here. Do not mistake this for a God of the Gaps argument, but rather take it as honesty that our knowledge has limits. If we cannot rule them out, then we should not.


What We Know

What are we sure of? We can say that God created our first parents, as He did all creatures, and that they were highly complex organisms. That description applies whether Adam and Eve began as zygotes with human souls growing in maternal bodies or as naked adults in a garden. As we know, biological evolution will never fully account for humanity because we are persons, corporeal body and rational soul, made in the image and likeness of God. It is not unreasonable to assume humanity began with a miracle. And if this biological mystery of life from inanimate matter and remote human origins from a common ape-like ancestor troubles you, then consider something nearer. Biology tells us that sperm and egg fusion is the beginning of life, but none of us know down to the subatomic event on a femtosecond timescale what exactly happened as our electrons swirled when we began to live. And we never will. At its most precise resolution, all our lives begin mysteriously.

Using reason and revelation, Catholics can both roll up their sleeves to explore what evolutionary science discovers about human origins and, simultaneously, believe that Adam and Eve existed. Besides, we are forward-looking people of faith, hope, and love. Until we have our answers, we can be assured of a truth St. Paul wrote to the Corinthians, “Now I know in part; but then I shall know even as I am known.” I can live with that.