April 3, 2010

Tim Murray
Dean of the Faculty of Humanities and Social Sciences,
Professor of Archaeology
Archaeology Program
La Trobe University
Victoria 3086

Tel: (61 3) 9479 2978
Fax: (61 3) 9479 1881
Email: t.murray@latrobe.edu.au

Dear Tim Murray:
I have read your chapter “The Power of the Past” in Questioning Collapse describing events in Australia, the chapter being part of a response to Diamond’s Collapse.  We agree that understanding the past can help with the future, and we are both hesitant about Big Theories.  Nonetheless I am stuck with a Big Theory because the evidence for it is so strong. 

The theory is that societies collapse not from outside influences nor from internal characteristics.  Societies collapse because of infertility caused by the existence of a large – more than a few hundred – random mating population.  I am sure you have never heard this proposed.  Common assumption is that genetic diversity is a good thing.  But my evidence is posted at nobabies.net in the March 25, 2010, posting of material I presented as a poster at the meeting of the American College of Medical Genetics in Albuquerque last month (along with other evidence and correspondence).  I suppose I went over my material with two dozen professional geneticists.  I was challenged more than once, particularly with my regards to Chinese history, but there was no serious argument against the basic principle. 

However, I get little comfort from the facts you present.  Tasmania was overrun, pure and simple.  Fertility seems to have played no role.  Aboriginal culture on the continent survives despite being overrun.  So far from being a story of collapse, we are looking at a story of success.  The question then must be, “How did they do it?” 

The time scale of collapse is about 300 years with a somewhat less severe cycle of 150 years.  Yet the Australian Aborigines thrived for more than a 100 times the 300 year limit.  Not bad, I say.

Now there are a couple of ways to survive.  One can survive in instability.  One part of the population goes infertile, dies out and vanishes while others expand.  The effect of this is to produce a kind of uniformity both linguistically and genetically.  Europe, which has been settled for almost as long as Australia, is far more uniform both in language and genetics, so one supposes that area has managed to survive by instability.  I fear I do not have a good reference on the homogeneity and stand ready to be corrected.  That would be no problem.  The message is that instability from infertility does not doom everyone so long as the population lacks intimate contact.  Obviously there is almost nowhere that now holds.

But to survive with diverse ancient languages and, I suppose, genetic lineages, stability is needed.  So I have a question.  Is it true, as I was told on a trip to Australia to see Haley’s Comet with my mother, that there is among the Aborigines a system of “skins?”  One would have the expected family connections, but there was also the skin system that cut across family lines.  There might be hostility between different skins that would not exist between allied skins or members of the same skin. 

If I was misled, so be it.  But if such a system actually exists, it might conceivably serve some purposes.  If the skin system was such that marriage within a skin was as acceptable as marriage within the local band, then two things come to mind.  One effect could be to limit inbreeding, an obvious and acknowledged danger for people living in very sparsely populated lands.  The converse would be that it could also limit outbreeding, an equally dangerous if little recognized phenomenon for just about everybody. 

So the second question is more quantitative.  Was this system so implemented that it regulated gene pool size, and what size was the resulting gene pool? 

I quite understand if there is no easy answer.  But if the answer is easy and well known, then I would much appreciate you letting me know.  Let me know what you think at all events.


M. Linton Herbert MD

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