May 29, 2012
To be posted on and

Concerning the special section in SCIENCE vol. 336. no. 6083 May 18, 2012 page 819
David Hamburg
1200 New York Avenue NW
Washington DC 20005 (email address did not work)

Dear Dr. Hamburg:
The reason groups of people are so beastly to each other is a consequence of the hard laws of evolution and a human brain that is pretty good but not very good.  An alert child who knows about speciation and about chromosomes should be able to understand that there is a finite limit to the size a randomly mating gene pool can survive.  Since you are a grown man, check out the logic in the video  The short message is that if speciation takes 2,000 generations then a population of 1,000 must eventually die because of speciation effects.  Obviously evolution has found a way to circumvent this by limiting, over several generations, the fertility of a population that gets too big. 

The effect of this fertility drop with falling consanguinity is documented in over 1,000 animal species (On the Regulation of Populations of Mammals, Birds, Fish and Insects, Richard M. Sibly, Daniel Barker, Michael C. Denham, Jim Hope and Mark Pagel SCIENCE vol. 309 July 22, 2005 page 609) and in human populations in Iceland (An Association between Kinship and Fertility of Human Couples Agnar Helgason et al. SCIENCE vol. 329 no. 5864 February 8, 2008 page 813 – 816) and in Denmark (Human Fertility Increases with marital radius. Rodrigo Labourian and Antonio Amorim.  GENETICS volume 178 January 2008 page 603 and Comment on “An Association Between the Kinship and Fertility of Human Couples,” Rodrigo Labouriau and António Amorim SCIENCE vol. 322, page 1634b December 12, 2008)  This is a law of nature.

If people had good brains we would have figured this out thousands of years ago or at any rate our attention would be riveted once the documentation was available.  Babies are of absolute importance.  Mate choice, the degree of consanguinity, is as important as sex.  A well functioning brain should immediately say, “Right.  We need to be rational about this.  There are too many people in the world and at the same time there are countries in the process of dying of infertility.  Now that we understand this, we can put populations where we want them and stabilize them.  This needs no coercion, only education.”

But our brains are not up to the task.  “Inbreeding is bad, since it depresses fertility” and “there are too many babies anyway” sit side by side without causing the distress that cognitive dissonance should produce. 

Our brains can also say, “I am in this group, not any other, and my group is superior.”  Groups who say this, who hate other groups, will tend to a degree to limit their mating pool size and reap the benefit of enhanced fertility.  Those who take the position, “Everybody is really the same.  Your choice of mate is  purely recreational,” will outbreed and in the long run die. 

Unscrupulous and power hungry people can exploit the logic of the survivors and gain status.  They also unfortunately tend to believe their own screed and start violent acts.

The violence of course does nothing.  If I pilot a drone over a suspected terrorist half way around the world it has no effect at all on whether my wife gets pregnant; that depends on how kin we are, and according to the article published in your journal depends on nothing else.  Besides modern conflict involves identity groups like nations or ethnic groups that are so large as to be biologically irrelevant.  They are so big that a random mate within is no different from any mate without.  Even feuding on the “Romeo and Juliet” scale is biologically worthless.  It does not effectively restrict cross-clan love but an understanding how this harms both groups might. 

Once people understand this, violence should sublime like a lone snowflake on a cold dry day.  Until then you can confidently expect the news to continue to be a crochet of carnage and history to be a march of dying societies.

How do you feel about this?  Let me know.

M. Linton Herbert MD 

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