April 12, 2010

Fred Pearce
c/o Beacon Press
25 Beacon Street
Boston, Massachusetts 02108-2892

Dear Fred Pearce:
I have read your masterpiece The Coming Population Crash (Beacon Press, Boston 2010).  You have taken the most important subject there can be, the arrival of babies and attempt to trace out all the known causes and effects.  The result is splendidly readable.  I like your style and vocabulary. I like the veiled references to MAD magazine and The Man Show.  I even like your font.  There is one bit of biology of the greatest importance that is known but that your research pattern could not possibly have found. 

To begin, let me tell you what my perspective is.  Many years ago at Harvard I was attending a clinic given by the renowned Dr. Fisher.  The patient had a difficulty with his arm.  Dr. Fisher asked him to raise the arm.  The patient only glared at the good professor.  Speaking with the utmost care, Dr. Fisher said, “You do not say, ‘The patient will not raise his arm.’  You do not say, ‘The patient cannot raise his arm.’  You say, ‘The patient does not raise his arm.’”  In so many seconds the professor opened a door for us to a mental room.  It was tidy and well lit.  There were no passions, was no will.  There was only clinical observation.  After all the information had been evaluated and everything that could be accounted for on an organic basis had been explained, only then did you admit will, the impact of disease on the patient and on those around for consideration. 

The will is a tricky thing to identify.  The word “fecundity,” like the word “fertility,” means either the number of patients a person or animal does have or the number it can have.  It is an observation.

The relevant observation is that the number of offspring a couple has is determined by their kinship and by little else.  If kinship is too close, fertility is suppressed.  This effect can accumulate over generations.  If kinship is too distant, fertility is depressed.  This effect also accumulates over generations.  According to the best available data, the ideal match is between third or fourth cousins as they calculate kinship.  That match maximizes the number of grandchildren.  First cousins once removed have a lower fertility.  Sixth cousin or more distant is worse than first cousin once removed.  More distant than that and fertility is below replacement.  This was published as An Association between Kinship and Fertility in Human Couples, Agnar Helgason, Snaebjoern Palsson, Daniel Abjardson, Pordur Kristjansson and Karl Stefanson, SCIENCE vol. 319 February 8, 2008 page 813.  There is more data, much of it summed up at nobabies.net the March 25, 2010 entry or http://nobabies.net/Albuquerque%20poster.html on my website, where I post other things such as more data, more thoughts and letters like this. 

If you go to the site, you will see that the fall in fertility is not constant.  It tends to level off below replacement with little evident change past about 10th cousin.  The curve will be very familiar to you after your research.  It is the course of world birth rates over the past fifty years both as a composite and broken down into regions.  It is the same curve over time as the birth rate of the United States, France, Germany, Italy and Britain.  The same curve has been seen in field studies of over 1,000 animals.

“And that, said John, is that.”

There is no need to ponder the injustices against migrants, the falling influence of the Catholic Church, draconian contraceptive programs, the cost of children, social services or patriarchy.  They are fluff.  The entire process is determined by the kind of biological process that would be admitted first to the professor’s bright room. 

It is not fair to speak of such momentous issues as fluff.  But they are rather like The Goddess figurines of the Stone Age.  All agree that they were fertility symbols, and I suspect they were a great occasion for peace, understanding and humanity.  But I do not believe a single one ever produced a baby. 

So how does the curve I describe play out over time?  Imagine a landscape with people.  Imagine they break up into social groups.  Those that are too large will suffer a population decline.  Those too small will go extinct from inbreeding.  Those of optimal size will grow until they are too large and then decline.  But those of a viable size and which are able to limit that size will persist.  Since inbreeding accumulates over time, each viable community becomes mildly inbred but persists.

Now enter a disturbance such as the advent of Europeans.  That will disrupt the little mildly inbred communities as people are freer to travel.  Limiting community size in all probability meant killing any outsider, and the new power will discourage this.

Presto the inbreeding suppression is removed; the claustrophobic dominance of those who maintained community discipline is escaped.  And there is a baby boom.  It happens all at once.  Predictably the dominant government goes into a panic and takes steps to limit fertility.  But in a couple of generations or so the communities have become too large and birth rate declines.  The government panics again and tries to slam the process into reverse.  But since they have no more comprehension of the process than did those devout keepers of Goddess figurines it does not work. 

Does this sound familiar?  It should.  You can call it “demographic transition” if you like, but I prefer the word “trouble.”  It’s short and businesslike.   

Although the process is well documented on the large scale, finding it locally is harder.  One wishes one could find a small isolated community and see how it plays out over time.  Such data is not available, but we can come close. 

Jared M. Diamond, “Life with the Artificial Anasazi,” NATURE, vol. 419 no. 6907, October 10, 2002 p 567.

The graph is from a paper by the redoubtable Jared Diamond.  The blue line represents rain as calculated from tree ring thickness.  The red line is the population calculated from the number of occupied dwellings each year.  The match is so close that either the Anasazi living there in Long House Valley were always on the brink of starvation or they were cultivating the trees.  Since the weather is probably not responsive to farmers (Do you remember the principle, “Rain follows the plow”?  It was just wishful thinking.), rain had nothing to do with it.  Besides you can tell when people move in; the number of houses increase a lot in a single year.  They come in groups.  If they were moving out in groups, we would see the same thing, but we do not. 

They died where they were – all of them – in a single generation following peak number of occupied houses. 

That is the outlook.  That is how it plays out.  Of course it could take longer for us.  These were hard working farmers.  As you point out, Russian men tend to die in their fifties.  So do NFL football players, keelboat men and Harvard Medical School graduates.  You can live longer if you figure out how to be easier on yourself.  Then again we might not take so long.  There is the possibility of some sort of unhappy social upheaval.  There is no evidence for violence in Long House Valley.  They worked themselves to death with the sweet tranquility of the twilight world you endorse at the end of your book.  Our society might not become that stable; it certainly is not now. 

The science is on the shelf.  You can check my references.  Unfortunately C. P. Snow was an optimist when he said that there were two worlds, the one of science and the other of the humanities, and they spoke with each other within each world but seldom spoke from one world to another.  In fact, scientists don’t even talk to each other, not much anyway.  They don’t understand each other any better than your average medical graduate understands any of them. 
The cure is absolutely straightforward.  There is a little more science to do to work out what a successful mating strategy is.  After that it is just a matter of letting people know.  I dread the idea of coercion in this.  It would be far too subject to abuse.  But ignorance itself is a form of coercion.  There is little time left.  Nobody has ever tried a rational mating strategy before.  It might be easy or not.  The rich world may already be a write off.  There is no reason to be sanguine about the less developed world.  They are not that far behind.  I had thought, before reading your book, that the real hope for humanity was the poorest countries, those still with a viable birth rate.  But now you tell us that AIDS is so endemic in many such countries that they are not that far behind the rest of us in dropping below replacement levels.  

What a stupid way to die.  The key to the cure is easy.  You have just read it.  Getting the word out is all it would take.  At least then we could try.
Ah to have your voice, clear, direct, wry, passionate, orderly, patient, humane, leaned, interested in the field and publishable.  Since I am none of the above, I wish I could get you to pursue this.  Please tell me what you think.


M. Linton Herbert MD 

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