Message-Id: <199706081247.IAA07678@mathlab.math.ufl.edu>
To: memetics@mmu.ac.uk
Subject: Re: Lamarckism and Category (?) Mistakes
Date: Sun, 08 Jun 1997 08:47:40 -0400
From: Omar de la Cruz <odlc@math.ufl.edu>
Chris Cleirig wrote:
>Nick Rose wrote:
> >What is directed mutation?
>
>Directed mutation is the idea that mutation of genes can somehow of itself
>proceed towards adaptation -- a view I don't hold. My point in mentioning it
>was to point out that if a selection process is wrongly interpreted as a
>mutation event, the "mutation" will seem directed toward adaptation, when
>in effect, an adaptive mutation (or recombination) has been selected in a
>population of variants.
`Directed mutation' is kind of an oxymoron. It came up in my first posting
about Lamarckism in memetics, where I wrote:
>OD: This modifications
>could be regarded as "mutations", which will later be subject of
>selection, but there is an important difference. This modifications have
>a DIRECTION, they are not random.
For me, the word `mutation' suggests randomness. So, "directed mutation"
has a paradoxical look, that I hoped suggested that something unusual was
going on.
Anyway, even if this variation is directed, it will be subject to selection.
A consistent tendency to variation in the direction of "adaptation" would
just speed up the evolution.
*Of course*, in biological evolution there are no directed mutations. Dawkins
argument about the "central dogma of embryogenesis", which I explained briefly
in a past post suggests a good reason for this: modify a gene, and the effect
in the phenotype, through embryogenesis, is virtually random; is like modifying
a line in a long computer program: the results are usually hard to predict.
In a meme, there is no complex embryogenesis between the copy of the meme in
the mind and the expresion of that meme (at least in many cases). So, directed
variation (that sounds better than directed mutation) is perfectly possible in
memetics. This point was made in the previous post.
What I want to argue now is that the "direction" in the variation generated
between replication events is fundamental for the idea of Lamarckism. What
I mean is that it is not enough to have "causal arrows" going from the
'phenotype' or expression of a replicator into the replicator (I'm trying to
make this argument for replicators in general, either genes, memes, programs
in an artificial life environment, etc.). For example, in the genetic/biological
case, we can say that a mutation caused by natural radiation is a consequence
of the phenotype, at least because of the fact that the particular organism
we are talking about hadn't grown a heavy lead shield around the gonads. But
that doesn't create a lamarckian effect in biological evolution. The reason
is that the change (mutation) is not directed, but random.
So, when I claim that memetic evolution has a lamarckian component, I don't
have to prove just that there is change from the expression of the replicator
back into the replicator (that would be easy). What needs to be proven is
that the change has direction (is not random). As I argued in the previous
post, the direction does not need to agree with the direction of "adaptation",
we just need non-randomness. And as I claimed in my first post about
Lamarckism, this can be studied experimentally. Please see my next post.
Regards,
Omar De la Cruz C.
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