Adam, Eve, and Crazed Grasshoppers

Recently one of my fellow parishioners sent me to a website about evolution.  It makes a point of refuting Christian doctrine by showing evidence for polygenism.

Polygenism is a scientific theory regarding the origin of mankind.  It proposes that the human species arose out of a sort of co-evolving group of hominids.  That group eventually split up and developed separately into the different ethnicities we have today.  As it says on the website:

“All the data clearly show that all modern humans, African and non-African alike, descend from one ‘homogeneous ancestral population in the last 100,000 years, with subsequent minor admixture out of Africa from Neanderthals.’ This goes against earlier theories that there is a much older divide separating West African from non-African populations.”

[Note: I hate it when people use the word “data” as a plural word and not a group singular.]

Thus, the author claims to disprove the Biblical description of a distinct two-person origin of humanity presented in the first three chapters of Genesis.  He goes on to note with some delight how “disproved” Biblical doctrines must to retreat into the realm of metaphor.

Today I wanted to take a look at two questions:

• First, what are Christians bound to believe in regard to Adam and Eve?
• Second, how would we reconcile this with modern science?

Our First Parents:

In a previous post I explained how Catholics are not bound to a wooden, literalistic interpretation of Genesis.  One is permitted to take certain elements of the narrative as a metaphor which nonetheless describes real history.

But this does have limits.  Catholics are not free to deny the existence of a real Adam and Eve - even if that wasn't necessarily their proper names.  Pope Pious XII wrote the following in his encyclical Humani Generis:

“When, however, there is question of another conjectural opinion, namely polygenism, the children of the Church by no means enjoy such liberty. For the faithful cannot embrace that opinion which maintains that either after Adam there existed on this earth true men who did not take their origin through natural generation from him as from the first parent of all, or that Adam represents a certain number of first parents. 

Now it is in no way apparent how such an opinion can be reconciled with that which the sources of revealed truth and the documents of the Teaching Authority of the Church propose with regard to original sin, which proceeds from a sin actually committed by an individual Adam and which, through generation, is passed on to all and is in everyone as his own.” - Humani Generis, 37

One interesting thing to note is a certain bit of wiggle room in this statement.  The possibility of polygenism isn’t permanently ruled out.  The phrasing is “it is not apparent how polygenism could be reconciled to the faith”.

Does this mean it might become apparent in the future?  Perhaps, but for now (and the foreseeable future) Catholics do not enjoy the liberty to subscribe to polygenism.  We must hold to a 2-person origin of humanity.



Three Ideas:

So how does an observant Christian approach the data which supports polygenism?  I’m not a biologist, but here are three ways I approach the matter.


Correct Assumptions?

First, every computer model is only as good as the assumptions built into it.  In the wake of Hurricane Katrina, I recall climatologists prophesying a continuous onslaught of large storms on the Gulf Coast. Their climate models predicted it would become the new normal.  We then went years before seeing another storm.  Obviously the models were missing something.

The population model shown on this website also has its assumptions.  In particular, it supposes a certain genetic mutation rate.  The site says:

"From these models, data on genetic differences within individuals, and estimates of ancestral generation times and mutation rates (rates of change at individual DNA bases), you can work out what the population size of our ancestors was at different times in the past." [ ]  “This conclusion, though, is provisional because it depends on estimates of mutation rates which are necessarily indirect.”

So it could be those rates have changed over time – throwing off their projections.

It would be interesting to know how far off it would have to be before you do arrive at a two-person bottleneck.  What if it only took slightly different values to see that kind of result?

Non-Genetic Changes:

But now let’s suppose the computer model is completely correct.  Are we at a dead end?

Not necessarily.

There have been fascinating discoveries in the field of genetics which have revealed the power of environment upon certain organisms.  Two organisms with the exact same genetic code can develop into very different creatures given the right stimuli.

One example is the desert locust.   It has two “modes”.  In its “solitary” mode it lives like an ordinary unassuming grasshopper.  But something freaky happens when you place it into close confines with its peers.  It transforms into an all-devouring locust.  Science Daily says the following about the phenomenon:

“Solitary and gregarious locusts are so different in looks and behaviour that they were thought to be separate species until 1921.”  - How A Brain Chemical Changes Locusts From Harmless Grasshoppers To Swarming Pests

Science writer David Dobbs described it like this:

“In the most infamous species, Schistocerca gregaria, the desert locust of Africa, the Middle East and Asia, these phase changes (as this morphing process is called) occur when crowding spurs a temporary spike in serotonin levels, which causes changes in gene expression so widespread and powerful they alter not just the hopper’s behavior but its appearance and form. Legs and wings shrink. Subtle camo coloring turns conspicuously garish. The brain grows to manage the animal’s newly complicated social world, which includes the fact that, if a locust moves too slowly amid its million cousins, the cousins directly behind might eat it.

How does this happen? Does something happen to their genes? Yes, but — and here was the point of Rogers’s talk — their genes don’t actually change. That is, they don’t mutate or in any way alter the genetic sequence or DNA. Nothing gets rewritten. Instead, this bug’s DNA — the genetic book with millions of letters that form the instructions for building and operating a grasshopper — gets reread so that the very same book becomes the instructions for operating a locust. Even as one animal becomes the other, as Jekyll becomes Hyde, its genome stays unchanged. Same genome, same individual, but, I think we can all agree, quite a different beast.” – Die, Selfish Gene, Die

Now let’s look back at the case of humanity.  Even if the genetic models of human history are completely correct, the true origin of our race could be something which transcends the bare script of the genetic code.  It could be an epigenetic change like the one which transforms a grasshopper into a locust.  This is something which would not be detected in historical genetic studies.


A Difference in Spirit:

The third explanation - given by Pope Benedict XVI and others – looks to man’s spiritual nature.  Metaphysical “human-ness” is not identical with having a particular genome.  One of the constitutive elements of a human person is an immortal rational soul.  Pope Benedict said:

“For it is not the use of weapons or fire, not new methods of cruelty or of useful activity, that constitute man, but rather his ability to be immediately in relation to God.  This holds fast to the doctrine of the special creation of man;  herein lies the center of belief in creation in the first place.  Herein also lies the reason why the moment of anthropogenesis cannot possibly be determined by paleontology: anthropogenesis is the rise of the spirit, which cannot be excavated with a shovel."  - Creation and Evolution: A Conference With Pope Benedict XVI in Castel Gandolfo, 16

So imagine a community of non-rational biological humans (NRBHs).  They are living together in a community of several thousand when suddenly two young whippersnappers are specially and miraculously endowed with an immortal rational soul.

They look just like their NRBH neighbors and yet have crossed over an existential boundary.  They have become "human" in the full sense.  Then their progeny -(even those interbred with the NRBHs)- inherit this nature until all the NRBHs are gone.

[It is hard for me not to compare this to the two protagonists of the movie Pleasantville who begin see in color]

Once again, such a transition would be totally invisible to genetic history models.  

Keeping it Real:

Christianity is not just a code of ethics.  It is a religion which makes real claims about the world and about the past.  As such, the opponents of the faith rightly believe they can undermine the faith by disproving these claims.

In the past they thought the claim of a distinct temporal origin of the universe would be disproven.  That… didn’t pan out.  Today the biggest battle is over the historicity of Adam and Eve.  Here they think they have a knock-out punch.  But hopefully I have provided some food for thought on how one can look at the scientific data and incorporate it into a Christian worldview.

Personally, my imagination draws upon a mixture of all three of the above options.  I imagine the first two humans being raised and cared for in a community of NRBHs.  But they find themselves remarkably different from their neighbors.  They see a more colorful world than they do – so to speak.  They separate themselves out and begin figuring out what it all means.  

And they hear God walking in the cool breeze of the garden.

Additional Sites:

Wired.com - How Locusts Learn to be Part of a Swarm

TOF Spot - Adam and Eve and Ted and Alice