> Cultural evolution has been occuring in earnest over only the last 10 to
> 100 thousand years. This is an insignificant period, genetically. We are
> all of one genetic mold, so to speak. In the time of recorded history
> culture has been changing so rapidly that what makes a "fit" human brain is
> dramitically different with each generation.
>
> Think of mental development as a growing meme-tree. The brain is designed
> to create ever more complicated branching meme-structures in the same way a
> tree is programmed to branch and foliate. Exactly how a tree or meme-tree
> grows, however, is primarily dictated by the environment in which it
> germinates and unpredictable developmental events. No two trees have the
> same shape, and no two minds do either...but, genetically, they are
> identical (or nearly so). It is the plasticity of the brain (or of a tree)
> which is its greatest advantage, not it's rigidity.
>
Perhaps we all are of one general genetic mold, but that doesn't
necessarily mean that we share all (significant) genes. It has already
been pointed out that differences in mental capability (that surely can be
genetic) may have large effects on which memes that are able to prosper in
different hosts. And also, there are genetic limits as to how complex
memes we, as humans, will ever develop (without altering our genes).
My point:
[1] We should *not* think of genes as directly determining memes. We
instead should say that genes produce the bodies that serve as the
*environment* in which memetic selection takes place. The analogy with
natural environments is almost complete; think of how the physical
environment influences large-scale trends in the genetic pool (the
existing organisms), while the main changes in the genes are due to
competition with other genes.
In the same way, our genes produce the world in which memes live, but is
mostly a static background, where meme competition takes place.
However, there may be some reciprocal effects. Think of the dramatic
effects on the atmosphere of the evolution of the photosynthesis, which
was a purely genetic idea. Therefore, we should suspect that memes may
affect genes, in extreme situations at least, via some version of the
Baldwin effect. But:
[2] We should *not* think of memes as directly affecting genes. We really
should not talk of memes at all, when discussing genes. As a gene
(borrowing Dawkins' 'thinking gene'-metaphor), you do not think of the
memetic development of your organism *in any other way* than 'does this
affect my survival?'. In this respect, memetic evolution is just not
relevant.
Further, if different memes affect genes differently, it is because there
is a genetic difference between between the hosts (i.e. something that is
not affected by genetics cannot be selected for/against). Therefore, if
we say that a meme affects the genes by affecting survival, we really are
saying that there is a gene that (via the memes) affect survival. So from
a gene's point of view, it's all genes! Which is the correct perspective,
as far as genetics is concerned.
Summary: Memetic evolution does depend on the almost static genetic
environment. Genetic evolution *has nothing to do with memetic evolution*;
that exists only in a much higher abstraction. Or, rather, memetic
evolution is as much in the phenotype as is a foot, and is not a part of
the genetic evolution. We should not confuse these two levels of
evolution.
>
> Genetic development does not significantly determine Memetic development.
>
In the above perspecive, this reduces to 'Genes must be thought of as
producing the background in which memetic development takes place', to
which I agree.
In contrast, I do, for example, *not* agree that this background does not
determine which memes are possible.
/*******************************************************
* Mikael Nilsson m94mni@student.tdb.uu.se *
* Student of Mathematics and Computer Science *
* University of Uppsala, Sweden *
*******************************************************/