April 12, 2010

Harry S. Dent
HS Dent Invetment Management, LLC
15310 Amberly Drive, Suite 390
Tampa, Florida 33647

Dear Harry Dent:
I understand you are an expert in using demographic trends to forecast the economy.  I have a great interest in demographic trends.  In fact I think I know in a semi-quantitative way what drives them.  The mechanism is as unsuspected as it is profound.  Since I live right over the bay in Largo, the best thing would be for me to take you out to lunch some day.  It would only take a few minutes to show you my material, after which you could do with it as you see fit.

If you are too busy for that, I shall try to point you in the direction I would go.  I saw your presentation in the movie “Demographic Winter” and was struck both by your eloquence and by the fact that I am not the only one who thinks that the present wave of infertility in the developed world is not a purely good thing.  In fact the evidence suggests that the future is far more grim than even that sober movie allowed. 

The fact is that in order to have an adequate number of children and grandchildren a couple must be sufficiently closely related.  Extreme inbreeding is, of course, destructive.  But the moment a gene pool size escapes severe inbreeding fertility rises to a maximum.  It then declines very rapidly with maximum stability occurring with a somewhat larger gene pool at more or less the inflection point.  Then fertility continues to decline but tends to level off below replacement levels.  Although the curve of fertility against kinship goes almost horizontal, the effect accumulates over – my best guess is 5 – generations.  Extinction appears to be a very real danger for a gene pool as large as something like a thousand. 

That oversimplifies matters.  I do not know it the first generation is affected but the weight of the evidence says yes.  (If not, things look very bad indeed.)  There appears to be evidence for the process to cycle with the greatest threat to social order coming at about 300 years or 10 generations.

If you would like to see the graphs I have collected and the results of my computer simulation, check out my website nobabie.net and look first at the March 25, 2010 entry.  You will also find other evidence my letters and other related material.  But it would be more fun to go over it together and in person.  Since the issue has become my life I am quite available most of the time.  And since demographic cycles are so important I am hoping you will create the time to see me.

Congratulations on your part in a splendid documentary about a crucial matter.


M. Linton Herbert MD 

There have been 3,830 visitors so far.

Home page.