Reflectorites
On Sun, 10 Sep 2000 15:18:27 -0500, Chris Cogan wrote:
[continued]
[...]
CC>Imagine that each
>organism's genome has but two genes, and that these genes can be
>gradated so that they can be indicated on an X_Y grid by two
>numbers.
I presume this "X_Y grid" is supposed to represent the environment?
But what is the "gradated" supposed to correspond to in the real world?
CC>Imagine that the offspring of each genome either occur
>exactly where the parent genome occurs, or only a small distance
>away, because the two genes can only vary a small amount for
>each generation.
I presume this means on the "grid"?
CC>Then, imagine also that there are certain parts of
>the grid where the organisms that have these genomes are not
>allowed to exist.
Why this smuggling in of teleological language if Chris doesn't believe it?
Why not just say where the bodies these genomes code for are not viable?
CC>If their x and y values land them in one of these
>areas, there is a small but bright flash of blue light and a Zzzzt!
>sound, and it disappears from the grid. This zapping effect is
>selection at work.
It is interesting how Chris is always on about Occam's Razor, i.e. "entities
should not be multiplied beyond necessity":
"Occam's razor ... a scientific and philosophic rule that entities
should not be multiplied unnecessarily which is interpreted as
requiring that the simplest of competing theories be preferred to the
more complex or that explanations of unknown phenomena be
sought first in terms of known quantities" (http://m-w.com/cgi-
bin/dictionary?book=Dictionary&va=occam's+razor)
But then what has this bug zapper called "selection" added to the
explanation? There is an environment, presumably represented by the "grid",
and "genomes" (and by implication bodies which are in fact what actually
gets `selected'). These are all that is necessary and sufficient to explain the
phenomena.
Some body traits coded for my some genes are not viable (or less viable
than others) in a given environment. They are eliminated if that body
containing them dies without replacing itself. There is no zapper that is not
already present in either the environment or their mortal bodies.
In the end, there is no such thing as "natural selection". It is just an
unnecessary metaphor that gives the *illusion* of doing something. Chris, if
he is to be true to his Occam's Razor reductionist principles, should
eliminate `natural selection' as an unnecessary entity.
I have been meaning to do this for some time, but now I will: I am going to
put natural selection in single quotes, either `natural selection' or natural
`selection' to indicate that I am talking about is really just a *metaphor*, as
Darwin himself originally admitted:
"If the reader is surprised to find natural selection disintegrating
under scrutiny, I was no less so. But when we reflect upon the
matter, is it so surprising? The biologists have innocently confessed
that natural selection is a metaphor. In the sixth edition of The
Origin of Species ... Darwin himself referred to natural selection as a
"metaphorical expression" and also said: "In the literal sense of the
word, natural selection is a false term....") and every experienced
person knows that it is dangerous to work with metaphors. As the
road to hell is paved with good intentions, so the road to confusion
is paved with good metaphors. Perhaps the sober investigators
should not have staked so much on a poetic device." (Macbeth N.,
"Darwin Retried," 1971, p.50)
but in the end came to think of as his God:
"... All he could believe in was 'my deity, `Natural Selection'" '
(Moore J.R., "The Post-Darwinian Controversies, 1979, p.344, in
Bird W.R., "The Origin of Species Revisited, Vol. II, 1991, p.210)
Darwinian evolutionary biology must be the only branch of modern science
whose central mechanism doesn't actually exist!
CC>But, whether a particular genome's offspring
>ends up in these forbidden areas or not depends on the variations
>that occur, and how close to one of the boundaries the parent(s)
>are
See above. All this would predict is a steady state tendency to equilibrium.
It is misleading to talk of `natural selection' doing anything positive. At best
natural `selection' eliminates the unfit. It does not create the fit.
CC>To make the image simple at first, just imagine that everything to
>the right of 10 on the X axis is "forbidden" territory. Then, if an
>organism's genome has an x_value of 5, and variations only occur
>in increments/decrements of 1, its offspring will be okay. But, if
>the parent genome(s) are at 10 already, then it is possible that
>some of their offspring will be at 11. Zap!
See above. This zapper metaphor overly dramatises what is actually non-
existent in the real world.
But accepting that some bodies coded for by some genes are disfavoured in
a given environment, all this would predict is at best only Stabilising
Selection, i.e. a steady state disfavouring of extreme bodily traits (and
therefore the genes which specify them) in a population.
What Chris needs is Directional Selection, i.e. a whole *series* of "x and y
values" and "X_Y grid"s to change (say) a land mammal into a whale in only
5-10 million years.
CC>Notice that, in this way of looking at it, selection has nothing to
>do, directly, with variation. It limits what variations may occur
>only by limiting the locations of *existing* genomes on the grid.
The fact is that "selection has nothing to do" *period* because it does not
actually exist!
CC>Thus, there won't very likely be any genomes that appear with an
>x_value of 30, because that's way too far from the *existing*
>genomes' range of variation.
This is true of naturalistic `blind watchmaker' evolution, but an Intelligent
Designer could make an integrated package of changes that *would* be
viable, as Dawkins admits:
"There is another mathematical space filled, not with nine-gened
biomorphs but with flesh and blood animals made of billions of cells,
each containing tens of thousands of genes. This is not biomorph
space but real genetic space. The actual animals that have ever lived
on Earth are a tiny subset of the theoretical animals that could exist.
These real animals are the products of a very small number of
evolutionary trajectories through genetic space. The vast majority of
theoretical trajectories through animal space give rise to impossible
monsters. Real animals are dotted around here and there among the
hypothetical monsters, each perched in its own unique place in
genetic hyperspace. Each real animal is surrounded by a little cluster
of neighbours, most of whom have never existed, but a few of whom
are its ancestors, its descendants and its cousins. Sitting somewhere
in this huge mathematical space are humans and hyenas, amoebas
and aardvarks, flatworms and squids, dodos and dinosaurs. In
theory, if we were skilled enough at genetic engineering, we could
move from any point in animal space to any other point. From any
starting point we could move through the maze in such a way as to
recreate the dodo, the tyrannosaur and trilobites. If only we knew
which genes to tinker with, which bits of chromosome to duplicate,
invert or delete. I doubt if we shall ever know enough to do it, but
these dear dead creatures are lurking there forever in their private
comers of that huge genetic hypervolume, waiting to be found if we
but had the knowledge to navigate the right course through the
maze. " (Dawkins R., "The Blind Watchmaker," 1991, reprint,
pp.73-74)
CC>Thus, current variation is limited by
>*past* selection, but not by current selection. The *next*
>generation's variations will be limited by what happens to *this*
>generation's genomes
Realise that "selection" is a metaphorical, unnecessary entity that adds
nothing to the explanation, and what have we left? Just that genomes
through bodies track the environment by differential reproduction in a
homeostatic equilibrium, producing *stasis*.
CC>But, variation itself is not under any direct influence from
>selection,
Especially when "selection" doesn't actually exist!
CC>which occurs after the fact (except when/if it occurs
>*during* the DNA_replication process when a variation already
>produced somehow might corrupt the rest of the reproduction
>process and "kill" the offspring genome even before it was
>completed)
I don't know why Chris thinks this is an exception. A "variation" in the
"DNA_replication process" is just another variation if it gets as far as an
"offspring genome" which is at least a zygote and by his own definition an
"organism's genome".
If it doesn't make it to a "genome" then it is not even a "variation".
CC>Naturalistic (i.e., Darwinian, loosely) evolutionists need to get
>away from "explaining" things in terms of selection, even though
>there is a certain "intuitive" tug to explain things that way.
So what has Chris been just doing if not "`explaining' things in terms of
selection"?
CC>Selection *does*, given suitable variations, explain why full_
>fledged, fully developed traits of a certain sort are present:
It doesn't even do that! "Selection" doesn't "explain" *anything* because it
really *isn't* anything.
"Differential reproduction" and "differential death" could "explain" some
things, because they are real entities. But "Selection" is just a *metaphor*,
and hence *cannot* really explain anything.
CC>Alternative, less_developed ones are constantly being selected out
>during evolution to fit a niche.
Nothing is really being "selected". It is just a metaphor for some organisms
in a population survive and reproduce more than other organisms and some
of this is due to inheritable physical traits less disfavoured in a given
environment.
CC>But, at each step of the way, it is
>the variation process that provides the raw material to select on,
>and if it does not happen to produce one set of variations that will
>be allowed
See above. Why this constant personification?
CC>to continue, the result will be that *other* variations
>will be allowed to continue, thus producing a different organism,
>or the organism will go extinct or move to another suitable niche,
>if the local selection "pressure" is too great
Another metaphor. There is no such thing as "selection `pressure'" either!
CC>Again, *variation* drives evolution. Selection *limits* evolution
>so that it can only occur along certain fitness pathways.
There is no "evolution" in the example Chris gave. It is a steady-state
system going nowhere.
CC>Of course, things are complicated in the real world by the fact that
>the "forbidden" zones are constantly changing, but the principle
>still applies.
The fallacy here is the implication that they are "constantly changing" in a
linear direction, rather than just fluctuating cyclically:
"But many biologists, looking at evolution over longer time
intervals, have noted that species are rarely modified consistently in
one direction long enough for significant evolutionary change to
accumulate. Even the Galapagos finches seem to oscillate, not really
"going any where" in an evolutionary sense. The reason is that short-
term environmental change tends to be cyclical, so natural selection
is not likely to keep pushing a species in any one particular direction
long enough for new species or major new adaptations to evolve.
Furthermore, every species is broken up into local populations, each
of which belongs to a different local ecosystem-making it even less
likely that natural selection will modify the entire species in any
particular way as time rolls on." (Eldredge N., "Evolution and
Environment: The two faces of biodiversity," Natural History, June
1998, pp.54-55)
[continued]
Steve
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