At 06:40 AM 09/22/2000, you wrote:
>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?
Chris
No. It represents the range of alleles for two genes. It doesn't matter
what they might code for, or what the environment is.
The general "motivating" idea here is that we can "place" each unique
"genome" in a unique location on the grid. But, different locations on the
grid can also be areas where the combinations of alleles that should go
there are not allowed/able to exist, and the reasons for such exclusion of
such of such combinations can be anything at all that can prevent it from
continuing to exist. It could be that the internal physiological functions
of the organism are not up to the task of keeping the organism alive, it
could be that the organism's reproductive facilities don't work, it could
be predators, disease, hunters, any "selective" factor at all. It could
even be that the genome, once created, cannot even support life in the very
first cell in which it occurs, because some variation screwed up its
control functions or the resulting cell's internal workings.
What the grid allows us to do is show the relationship between alleles and
genetic survival without needing to know, at this stage, what selective
factors are present. The genome doesn't "know," in positive terms, what the
environment is like. It "knows" only what has been safe for its ancestors
to "assume."
The grid metaphor also allows us to see easily and clearly that it's
variation that provides the raw material for selection, and that, without
selection (of *any* type), if variation is random, variations will run
rampant over the whole genetic "space," producing, in time, every possible
variation within a finite distance from the starting point. That is, all
possible alleles of all genes will be represented by a dot on the grid.
It does give us a means of studying selection, however, because we can
change the areas on the grid where allele-combinations are not able to
reproduce. For example, if we make a solid and thick circular ring around
the starting point, the ring will fill with dots, and some dots will go
into but not survive in the ring, but none will come to exist outside of
the ring. Evolution will be thwarted. But, if there is a pathway of
viability through areas of inviability, small variations will gradually
result in dots filling in all locally-available points on the grid.
In multidimensional terms involving one "dimension" for each possible
variation of a genome, if such pathways exist, dots will come to be present
in all areas reachable by such small steps from the starting point
(assuming the selective factors don't change, which they do, of course). If
we add changeability of selective factors, the same principle still
applies, but now we have to ensure that there is a path through time in the
sense that, between the starting point and any point of interest at some
ending point, there is a continuously existing area of viability that has
always had a population of dots in it, like a group of people continuously
moving so as to stay in a spotlight beam; eventually they will cross every
area the beam does, and will end up wherever it is aimed.
This metaphor will become important later when we discuss the "things
intelligent causes can do that unintelligent causes cannot," because there
are potential differences, depending on selection factors. For just one
example, in the case of the wide ring around the starting point, an
intelligent cause could simply *place* a population of dots outside the
ring (i.e., could make new alleles with values that put the resulting
genome outside the ring). Intelligent causes could also put genomes in
areas of viability that are *inside* of areas of inviability. In the real
world, we are finding that there are many such areas (a tiny few of which
we are beginning to populate by technological genetic recombination).
The question of ID might thus be formulated as: Are there now or have there
ever been genomes that could not come into existence as the result of a
series of small(ish) variational steps from nearly four billion years ago?
If there are, then a good step has been made in the direction of supporting
at least naturalistic ID (i.e., naturalistically occurring aliens, etc.).
If there are not, then pure naturalistic evolution still stands as the best
theory so far.
Note that CSI, irreducible complexity, and functional complexity are not
enough to exclude stepwise evolution, because stepwise variations will
eventually reach all areas of viability that are not completely closed off
from access by surrounding areas of inviability at suitable times. What has
to be found are locations in genetic space that do not and have never been,
at the right times, and for long enough, in open contact with outside areas
of viability. I will give a very obvious example to make the idea clear.
Modern computers did not evolve in what we typically call "Nature." In
fact, we don't even know of a genetic code that *can* directly produce
something like my PC (i.e., by "directly," I mean without producing
something like humans first). Thus, if we come to an Earthlike planet and
find the equivalent of IBM PC's lying around, we can be pretty sure that
they didn't evolve naturally and without something intelligent first
evolving to produce them.
Another example might be the appearance of man at the first point in
prehistory where humans could survive if they had existed (such as,
perhaps, sixty million years ago). If it could be *proved* that man existed
at that time (and that no other possible naturally evolved precursor
hominids existed first), I'd say that it was good support for some kind of
design. I pick that time because it seems to me that human genomes might
have been viable but not yet accessible by small genetic variational steps
from then-existing genomes. In this case, the problem would not be barriers
in genetic space, but distance from existing genomes in that space
(variations don't spread instantly from the starting point to all available
genetic space; the flow is more like the flow of molasses, so if available
genomes are too far away from a region of viability, there won't be any
genomes in that area for some time).
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