Re: Allan Isaac's suggestion about choice behavior being shared with  
animals.  
  
This discussion takes us back to Adam Smith, and his question about whether  
dogs trade. For Malthus, the key issue was that humans have foresight, and  
can therefore anticipate the consequences of actions which have not yet  
happened in such a way as to make plans that avoid negative consequences  
(like too many children). Malthus also indicated that human foresight led to  
the voluntary organization of institutions like private property, marriage,  
and markets.  
  
Darwin's natural selection mechanism for evolutionary adaptation among  
animals is Malthus' economic agents without foresight.  
  
See Sandra Peart and David Levy's recent essay on "Happiness, Progress and  
the 'Vanity of the Philosopher'" at  
http://www.econlib.org/library/Columns/y2005/PeartLevymalthus.html. I also  
have a piece now written on Malthus, which will be available in the next  
couple weeks.  
  
Ross Emmett