Re: Behe, common descent, and life on the edge

On 7 Mar, 20:50, Chris Rohrer <zonotric...@xxxxxxxxx> wrote:
I'm just a casual observer to the evo/ID debate and a mostly lurker
here. I know I should just buckle down and read the books, but why
should I work when I can consult the collective wisdom of all you
folks? Can anyone clarify some points of confusion for me?

My understanding of Michael Behe's position on origins is that he
accepts an old earth and common descent (I'm not sure if he goes so
far as accepting a universal common ancestor). If he were not so
deeply entrenched in the ID political movement, he might even be
charitably called a theistic evolutionist. The gist of The Edge of
Evolution, as I understand it, is that natural selection and mutation
are adequate to produce minor variation but insufficient to generate
major new structures or body forms (e.g. phyla). In other words, the
EOE is simply a new retelling of the old micro-/macroevolution
distinction. Behe's theoretical "edge" limits evolution to creating
variation within kinds and prevents the evolution of new kinds.

Here is the source of my confusion: Doesn't the EOE negate the
possibility of common descent? How does Behe reconcile common descent
with his argument against it? Is my understanding of Behe wrong or
does he hold two contradictory points of view (not that that has ever
happened in the course of human history)?

His point is that evolution happens by intelligent (supernatural)
guidance in addition to random mutation and natural selection.

Is genetic front-loading Behe's purported mechanism for generating
major new forms? Front loading means that the original primordial
cell was endowed from the gitgo with all the genes that would come
into play later on. That is, the universal common ancestor cell
already had genes for lips and livers and gills and puppy dog tails;
they just were not expressed at the time; perhaps they were locked in
the junk closet. If front-loading is how organisms find the way to
generate new anatomical structures, body plans, or biochemical
processes that can result in new "kinds" (macroevolution), then
presumably it works by a random mutation allowing a pre-existing but
suppressed gene to switch on, and the newly activated gene is
preserved by natural selection if it is adaptive. Present-day genetic
variation among organisms is due to degradation over time from the
original form that had everything (shades of The Fall!) along with
variation in which genes got switched on by mutation. Is this
characterization of the front-loading idea correct?

Possibly, but I actually think that the original idea was that the
sleeping genes were activated by some sort of generational clock or by
external (divine) intervention.

Front-loading would change the math of the EOE substantially, since
mutations would not have to gang up to create a whole new structure
from nothing (which Behe calculates as being vanishingly improbable).
Instead, mutations would only have to trigger the regulatory genes
that control expression of the novel structure. This would seem to
have a considerably higher probability.

Ok.

I've learned never to expect too much internal consistency from the ID
crowd, but, in their terms, if there is front-loading, then there is
no "edge" of evolution, because it is possible and probable to
generate any new structure. On the other hand, if there is an "edge,"
then there can be no common descent or macroevolution (which Behe
apparently accepts). Can anyone explicate the paradox for me?

Their point is that without intelligent (supernatural) intervention,
either in the form of continuous tweaking or in the form of front-
loading, there would be an edge of evolution that would have prevented
modern lifeforms from evolving.

Of course their argument are flawed.

Chris Rohrer

.

Relevant Pages

  • Re: Evolution and natural selection which is the cause and effect
    ... is conflating evolution by natural selection with "the overall ... (And I will just note again that Michael Behe holds exactly that position.) ... "Common Descent" to Behe likely does not exactly match your idea. ... So you would hide and pretend that directed mutation and development ...
    (talk.origins)
  • Behe, common descent, and life on the edge
    ... accepts an old earth and common descent (I'm not sure if he goes so ... Evolution, as I understand it, is that natural selection and mutation ... Is genetic front-loading Behe's purported mechanism for generating ... already had genes for lips and livers and gills and puppy dog tails; ...
    (talk.origins)
  • Re: Evolution and natural selection which is the cause and effect
    ... is conflating evolution by natural selection with "the overall ... (And I will just note again that Michael Behe holds exactly that position.) ... "Common Descent" to Behe likely does not exactly match your idea. ... As far as I know, he has made no claim about how, say, bacterial flagella originated, except that 1) it didn't involve random mutation, and 2) it involved intelligent design. ...
    (talk.origins)
  • Re: Evolution and natural selection which is the cause and effect
    ... is conflating evolution by natural selection with "the overall ... "Common Descent" to Behe likely does not exactly match your idea. ... By random mutation and natural selection, ... He would invoke "intelligent design" as an explanation ...
    (talk.origins)
  • Re: Evolution and natural selection which is the cause and effect
    ... is conflating evolution by natural selection with "the overall ... "Common Descent" to Behe likely does not exactly match your idea. ... He would invoke "intelligent design" as an explanation ... I agree with him that common descent doesn't explain differences among species -- for that you need some kind of mutation, ...
    (talk.origins)