inclusive fitness and the Yanamamo

Sun, 30 Jan 1994 23:16:06 CST

I agree with Forstadt's skepticism, and he's chosen the perfect example of
the internal contradictions of the inclusive fitness argument. Depending
on which edition of the Yanamamo you read, Chagnon either discusses the
frequency of female infanticide among the Yanamamo or (in later editions)
hints that it is there but that he won't discuss it because he doesn't want
the Brazilian authorities to know about it. But to say that is to let the
government know that Yanamamo do it and that he has data on it. I think that
is a thin ploy for not including data that destroys his argument on inclusive
fitness (while explaining away the absence of data that readers of his
earlier editions know is there). If an animal maximizes its fitness, it does
so only by producing offspring, not by not producing offspring. But the
practice of female infanticide not only reduces the fitness of the parents,
but also resuces the fitness of the offspring of their offspring, thereby
reducing, not maximizing fitness, inclusive or otherwise. Now, the way of
getting around this contradiction is to posit a digital computer in people's
heads that is programmed with a cost-benefit analysis such that before
killing a girl baby, one or bth parents have already calculated the short
term costs vs. the long term benefits in terms of net offspring one or two
generations hence. Of course, not having presented any detailed data on
any actual cases of female infanticide (because the government might find out
what he's already told them), Chagnon does not have to offer any data that
said algorithm is in any Yanamamo's head. The argument circles endlessly.

Let me end with a story that I think epitomizes the sociobiological argument.
It is a Sufi story about the fool who was given a jug of wine to take to the
wise man. The fool, being a fool, walked along the road heedless of its
twists and turns, of other people and of the ruts and rocks in his path. He
stumbled on a rock, fell, and broke the jug. Only the neck of the jug remained
intact. The fool continued on his way and, reaching the wise man's house, said

While I was bringing you this jug, a naughty stone jumped up, broke the jug
and stole the wine.

The wise man asked, "Why, then do you bring me the neck of the jug?"
The fool answered, "To prove to you that my story is true."

Mike Lieber