Message-Id: <199706081209.IAA07631@mathlab.math.ufl.edu>
To: memetics@mmu.ac.uk
Subject: Re: lamarkism in memetics
Date: Sun, 08 Jun 1997 08:09:21 -0400
From: Omar de la Cruz <odlc@math.ufl.edu>
Nick Rose wrote:
>
>Omar de la Cruz wrote:
>
>(just to pick up on one point you made)
>
> >Nevertheless, there are cases when people modify memes with the
> >goal of making them better replicators.
>
>This is very much like Durham's co-evolution line, where he
>suggests that people consciously select and manipulate memes.
>The idea that some 'agency' can pick or modify memes denies the
>central 'bottom up' simplicity of the original idea. People do
>NOT modify memes; memes modify people - otherwise why do you need
>evolution of culture to explain its complexity? Dennett goes
>into this in some detail.
>
>This may have been intended as short hand? If so I would plead
>with you not to use it without ensuring first that it can be
>converted back into 'bottom up' language - i.e. in terms of
>differential survival.
Nick:
It wasn't intended as short hand. I maintain my position that
the intergenerational changes suffered by memes are in general,
directed. This direction is sometimes the direction of
"adaptation", that is, this changes in average make the meme a
more effective replicator, but sometimes this direction can
be the opposite, or even "orthogonal". When the direction of
the intergenerational change agrees with the direction of
"adaptation" we have a speeded up process of evolution: the
memetic equivalent to the giraffe that stretches its neck to
reach high leaves, and then has long-necked offspring. In the
opposite case we have a slowed down evolution, if any.
*Off course*, this by no means negates the role of selection in
memetic evolution. Just that, in general, we have to consider
the possibility of dealing with lamarckian effects, speeding
up, slowing down or deviating the process of evolution, where
selection plays a very important role.
Biological evolution is a special case, where there are no
lamarckian effects involved, and all evolution is produced by
selection. But alternatives are conceivable. Imagine a gene
or complex of genes that produces the following effect: some
"organ" studies the body of the owner just before the production
of gametes, learns about the modifications of the body (produced
by use and disuse of parts, not mutilations), and somehow codes
this information in the genotype of the gamete. These genes
would be making themselves a good favor, because in general
the modifications to the body of the parent tell information
about the environment where the new individual is likely to
be born. If the parent has strong legs, that means probably
that it is living in the plains, where running is an advantage.
So it is good for the new individual to be born with stronger
legs, because he will probably be born in the plains. But
more important, it will be good for the 'gene-for-lamarckism',
so regular evolution (by natural selection) would spread
the 'lamarckism' in the population.
Then, why there is no lamackism in biological evolution?
Perhaps there is no final answer for that, but Dawkins makes
a good argument in `The Extended Phenotype'. Basically, his
point is that information can flow from genotype to phenotype
but not backwards because of the particular method of embryo-
genesis, which goes like a recipe, interpreting instructions
in a sequence until you get the cake. From a cake you cannot
produce a recipe, since what you have is the final product.
Same thing with the body, information about the final product
does not give you information about the original recipe (genotype),
or about how to modify that recipe to get a body similar to
the modified body of the parent.
Does this argument work in memetics? I don't think so.
In my example about the preacher/evangelist that introduces
the story of the Doubting Thomas into the gospel because he
thinks that it can make it a better replicator (even if he
is not conscious of doing exactly that), there is no problem
in modifying the story in the head to introduce the new
episode (we still don't know how the brain works, but we
know that we can do that to a story--if you have ever made
up a excuse you know what I'm talking about). In other words,
there is no complicated embryogenesis from the story in my
mind to the story I tell with my mouth --at least, the complexity
of the process is masked to me. Somehow, the information in
this case can easily go both ways.
My conclusion is that a general theory of evolution must have
place for lamarckian effects, not only selection. Perhaps
embryogenesis in other planets goes in a different way, where the
gametes have tiny copies of the final individual they are going
to produce, making it easy to have lamarckian feedback just before
gametogenesis.
But we don't have to imagine such a planet. Memetics produces
an example of an evolutionary process where lamarckian effects
play a role.
Regards,
Omar De la Cruz C.
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