Re: The evolution of "evolution"

From: Dace (
Date: Fri 07 Oct 2005 - 21:36:05 GMT

  • Next message: Scott Chase: "Re: The evolution of "evolution""


    > Ted
    > To be specific, you commit two kinds of errors in your essay:
    > 1) misrepresentation of neo-Darwinism
    > 2) premature declaration that some kind of
    > "memory" theory would 'explain' ontogenesis
    > The grossest misrepresentation of neo-Darwinism
    > (there are several more minor ones) is in your
    > use of Hoyle's fallacy. For instance,
    > "The Hyacinth macaw can crack a nut with its beak
    > that you or I would need a sledgehammer to open.
    > Is all that colossal strength nothing more than a
    > side-effect of a chance mutation in the macaw's
    > genetic toolkit? How many millions of such coding
    > mistakes had to come and go before the right one
    > announced itself, and at last the bird got its meal?"
    > and again later:
    > "Like a toy in a cereal box, every defining trait
    > of every species on Earth comes with a special
    > mutation hidden inside. Genes, you might say,
    > work in mysterious ways. We don't know why the
    > right mutation comes along at the right moment­it just does!"
    > and again:
    > "What about the creation, from scratch,
    > of trillion-celled furry animals with big
    > ears and buck teeth? Apparently, DNA is the one
    > thing that really can pull a rabbit out of its hat."
    > No scientist proposes any of the above 3
    > scenarios. None ever has - even the
    > "mutationists" of the 1920s had a much more
    > refined and sophisticated view than the one you
    > claim we have today. Mutationism went out the
    > window when Fisher showed that Mendelian genetics
    > did after all fit natural selection.

    You've taken my statements out of context. I make it plain in my article that such mutations merely provide the raw material for natural selection. The question is the source of the variations environmentally selected. Is it random mutations in our nuclear "determinants," as Weismann claimed, or is it the adaptations made by creatures in the course of their lives, as Darwin claimed? Clearly, the second accords better with common sense. A theory that can account for transmission of acquired adaptations is inherently more plausible than Wiesmann's alternative.

    > As for "memory" explaining ontogenesis, I
    > suggest you take a look inside the pages of
    > journals like "Developmental Biology",
    > "Development", "Mechanisms of Development" or
    > "Genes & Development". Enormous strides have
    > been made since the mid-80s in understanding
    > things like limb and axial development at the molecular genetic level.
    > A lot of your problem is that you're not up to
    > date on the subject you are professing to critique.

    On Scott's recommendation I had a look at Gilbert's textbook on developmental biology. However, I agree it would be beneficial to look at a few journals as well.

    > >Gene theory, on the other hand, has virtually nothing to say about
    > >ontogenesis. Researchers can only point out that a particular gene
    > >corresponds to a particular trait and that this effect follows from the
    > >presence of a particular protein. So, the gene that results in brown
    > >provides the template for the enzyme that catalyzes the relevant pigment.
    > >That's it. No gene for how the eye is to be structured, what its parts
    > >or how they're assembed, just a template for a protein that influences
    > >appearance. No blueprint, no developmental program, nothing of
    > >to the emergence of bodies from eggs. Lacking any compelling reason as
    > >why we should reduce the organism to its genes, we have no reason to
    > >evolution to the transmission of genes.
    > This is a late-1940s view of developmental genetics. Beginning in
    > the early 50s with Ed Lewis's work on the genetics of body plan in
    > Drosophila through to Jani Nusslein-Volhard and Eric Wieschaus's
    > molecular isolation of those genes from the late 70s onwards, it has
    > been possible to define the blueprint for how to make a fly from an
    > egg. Lewis, Nusslein-Volhard and Wieschaus shared the Nobel Prize
    > for this in 1994. Since the late 80s, Nusslein-Volhard has been
    > repeating the successful paradigm for the development of the
    > zebrafish. These genes do structure eyes, they do program
    > development, they are of major consequence for the emergence of
    > bodies from eggs. You can mess around with them and produce flies,
    > fish or frogs with all kinds of tailor-made odd developmental programs.

    I overstated my case regarding the structure of the eye. Any trait that varies from one individual to another ought to reveal a genetic component. This would include not only eye color but quality of vision and the shape of the eye. It would not, however, include the fundamental "design" of the eye. I put design in quotes because, in reality, there is no design for any feature of any organism on earth. There's no blueprint, in either the mind of God or the nucleic acids of chromosomes. Embryos merely mimic, on the basis of species memory, the developmental steps of their predecessors.

    > There are literally 100s of references I could give you. Try this
    > one for a start on eye development:
    > stract&list_uids=15950457&query_hl=3

    Here's the abstract from that article:

    "Animal eyes with widely different anatomical designs have long been thought to arise independently, multiple times during evolution. This view was challenged about a decade ago by the landmark discoveries that Pax6, a highly conserved transcription factor, plays a key role in eye morphogenesis in both flies and mammals. Since then, more evidence has emerged in favour of the redeployment of Pax6 and some other developmental control genes within the genetic program underlying eye formation throughout the animal kingdom. Recent work has indicated that other members of the Pax gene family play a pivotal role in eye morphogenesis. The Eye gone gene regulates eye growth in Drosophila, whereas the PaxB gene is implicated in visual system development in jellyfish, the most basal organism possessing eyes."

    As you can see, the authors make no claim for having discovered a design for the eye of any species. They merely point out what has long been established, namely that genes "regulate" or influence development. What genes do is to cause development to go down one path as opposed to another. By causing some proteins to be produced but not others, genes distinguish individuals from each other. They do not provide the overall plan of development, only tweaking it one way or another.

    Genetic reductionism is problematic to say the least. First starters, as Harry Rubin points out, the sequential combination of genes required to produce even the simplest organic compounds is vastly more complex than the sort of physical problems that yield to calculation. Gene combinations are
    "transcalculational." Like Newton's three-body problem, there literally is no solution. Genes therefore cannot mechanistically determine how they must combine to produce tissues, organs and bodies. The only possibility is they're mimicking previous, similar genomes on the basis of memory.

    Secondly, cells are founded on molecular disorder. A cell can be comprehended only according to large-scale patterns of activity, such as the creation of membranes or the activities of organelles. At the level of the molecule, nothing can be predicted, any more than a physicist can predict the activities of an individual molecule in a gas. The order of a cell is not reducible to its component molecules, including DNA. It is thus holistic, as the term was defined in 1926 by Jan Smuts: the whole cannot be understood according to its parts and their interactions. It's the cell itself, not its genes, that provide its order. Genes are merely instruments utilized by the cell to enable it to stay within its functional bounds.

    Reductionism isn't so much a theory of life as a theory of machinery projected onto living systems. Of course, machines don't have self-nature. Yet a theory of life is ultimately a theory of self. The fundamental unit of a cell is the cell taken as a whole, i.e. the cell itself. Its material constituents are only accidental features of the cell easily replaced with other atoms and molecules. So too, the mind is the person taken as a whole rather than reduced to chemicals in the brain. What you are, fundamentally, is yourself and only secondarily the atoms comprising your body. Your consciousness, your emotions and thoughts and memories, all of this is absolutely real and not merely the primitive misunderstandings of premechanistic peoples.

    As with cells and people, species also cannot be understood outside a strictly holistic model. A species is not reducible to the members comprising it but exists above and beyond those individuals. H. sapiens exists as a whole, and genes merely enable it to *individuate* into autonomous manifestations of that whole. Just as the activities of brains make no sense without the concept of mind, organic development requires a species mind. We may also refer to mind as field, as in electromagnetic or gravitational fields. The implication, long-since grasped by physics, is that matter possesses unexpected properties that enable it to act at a distance. We may refer to this as extensive materialism in place of reductive materialism.

    Given the impossibility of genes mechanically producing bodies, a theory that limits the role of genes to influencing development in a larger, holistic context is clearly preferable. The same goes for evolution. A theory that bases the source of variations on the living adaptations of organisms is clearly preferable to one that substitutes intelligent adaptation with genetic accident. Intelligence will find its way back into biology one way or another, and we're better off this way than the supernatural way. There's nothing magical or supernatural about fields and memory.

    As Descartes pointed out, self-existence is self-evident. We start with this and then move on to the mechanics of bodies. You've got it backwards. You begin with the assumption that mechanics explains everything and then, when the mechanistic model conflicts with our own experience of living, you assume that this is somehow an illusion, as if consciousness is simultaneously magician and audience, both source and recipient of hallucination. It's not enough to show that the facts just might fit the mechanistic model. You must show why, despite its obvious shortcomings, the mechanistic model is preferable to the holistic model. Holism is the natural approach to organisms, while genetic reductionism is merely an
    *artifice* invoked to account for the same outcome through different means. Of the two, it's the atificial model that bears the closer resemblance to the supernatural view, with its emphasis on a cosmic Mechanic who creates each species according to his design.

    Finally, a comment on the memetic dimension to all this. The mechanism meme gains its strength from our day-to-day experience of simple mechanical operations. It seems crazy to us that an event could be caused by another event remote to it in space or time. This is why Leibniz accused Newton of introducing magic into philosophy with his theory of gravity. It also gains power via repulsion from another meme, the one that says wine is blood. In each case, there seems to be no way of getting through to someone in whom the meme is deeply rooted. The cracker is Jesus. The DNA is you. Like mirror images, these beliefs seem opposite at first glance but are really the same.


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