X-Message-Number: 20278
Date: Thu, 10 Oct 2002 22:22:31 +0200
Subject: Re: "The future of death" 
From: David Stodolsky <>

This is clearly off:

http://www.prb.org/Content/NavigationMenu/Other_articles/July-September_20001/
How_Many_People_Have_Lived_On_Earth_.htm

> Our birth rate assumption will greatly affect the estimate of the 
> number of persons ever born. Infant mortality in the human race's 
> earliest days is thought to have been very high   perhaps 500 infant 
> deaths per 1,000 births, or even higher. Children were probably an

This rate of infant mortality, 50 percent, is that of apes, in which 
active child care is absent. Human rates have always been lower than 20 
percent.


> economic liability among hunter-gatherer societies, a fact that is 
> likely to have led to the practice of infanticide. Under these 
> circumstances, a disproportionately large number of births would be 
> required to maintain population growth, and that would raise our 
> estimated number of the "ever born."

The idea of children being an economic liability among hunter-gatherer 
societies is pretty funny, considering there was no economy. If we look 
at Salin's book, "Stone Age Economics", we find people were "working" a 
few hours a day, or at least less than the 8 hour shifts typical of the 
industrial economy.


If we assume the article's figures are off in proportion to the error in 
infant mortality, then the total humans ever born is about 40 million. 
Thus, 15 percent of all humans who ever lived are alive today. However, 
the estimate for the appearance of humans, 50,000 BC, is also totally 
off, since humans have existed for about 120,000 years. So, it doesn't 
look like this writer did his home work. Projecting the figures out a 
few hundred years would certainly give a crossover point, considering 
life extension technologies and population expansion with space 
colonization.

A more interesting figure might be the percentage of scientists alive 
today, of those who have every lived. Scientists have the ability to 
combat death by directing their work in certain directions, so the 
figure is more interesting.


Jones, et al. (1992). Population Growth. Cambridge Encyclopedia of Human 
Evolution. is one source for figures that could be used in a more 
reliable estimate.


dss

David S. Stodolsky, PhD    PGP: 0x35490763    

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