Re: Behe book review: Pa. scientist again attacks evolution

On Aug 21, 2:05 am, Glenn <GlennShel...@xxxxxxx> wrote:
On Aug 20, 7:09 pm, hersheyh <hershe...@xxxxxxxxx> wrote:

On Aug 20, 6:44 pm, Glenn <GlennShel...@xxxxxxx> wrote:

On Aug 20, 2:38 pm, hersheyh <hershe...@xxxxxxxxx> wrote:

On Aug 20, 4:40 pm, Glenn <GlennShel...@xxxxxxx> wrote:

On Aug 20, 11:20 am, hersheyh <hershe...@xxxxxxxxx> wrote:

On Aug 19, 9:38 pm, Glenn <GlennShel...@xxxxxxx> wrote:

On Aug 19, 5:44 pm, "Steven J." <steve...@xxxxxxxxxxxxx> wrote:

On Aug 19, 7:01 pm, Glenn <GlennShel...@xxxxxxx> wrote:

On Aug 19, 4:30 pm, noctiluca <robertlc...@xxxxxxxxxxx> wrote:

-- [snip]

Show us how ID can explain the supra-scapular ligament, benthic
structures, or anything at all. Keep in mind that "intelligence did
it" is not an explanation any more than "angels that look like Woody
Harrelson did it" or "wood nymphs did it" or even "Winnie-the-Pooh did
it." Intelligence is not a causal agency. Intelligence is an attribute
of some causal agency, just as generosity or spirituality or tone-
deafness might all be attributes of a causal agency. So in order to
demonstrate that ID can indeed explain anything you must be able to
show us the designer.

Tell it to Darwin, since in the absense of the knowledge of random
mutation and cellular function, natural selection isn't a causal
agency and can't even be imagined as one. Intelligence is most
definitely a mechanism, imbecile, just as generosity is as well. It
isn't necessarily the first cause, but then science doesn't require
knowledge of everything, or there wouldn't be need for science.

Given that Darwin *did* imagine natural selection in the absence of
knowledge of mutations or how cells function, your statement appears
to coexist somewhat uneasily with historic facts. To recognize
natural selection as a causal agency, one needs to note that [a]
organisms vary among themselves, [b] organisms pass on traits to their
descendants, [c] some of the variation among individuals is among the
traits that are passed on to offspring, [d] not all offspring survive
to reproduce themselves, and [e] some of these inheritable differences
cause some of the difference in which organisms survive to pass on
their genes. How traits are passed on, how new variations arise, and
how the mechanisms of inheritance interact with those of development
are good things to know, but one does not need to know them in order
to recognize natural selection.

Those are *observations*, not mechanisms. All you've said is "yuh
huh", without explanation. Without mechanism, natural selection is an
inference based at best on an inference, not on a mechanism, and not a
mechanism itself. Recognize that.

snip more long winded bull***

Are you agreeing that those observations are accurate?

Not sure what you mean by accurate, but I doubt the question has any
relevance. It isn't me you should question, but Darwin.

As to the mechanism of natural selection, it is clearly stated that
the environment sometimes (not always, neutrality and drift certainly
also happens) discriminatively interacts with and *causally* affects
the likelihood of one of two phenotypic variants to be reproductively
successful. That is, the environment is the independent variable
that, when it *causes* a *significant* difference in reproductive
success of one of two variants, is said to selectively discriminate
between the phenotypes or variants. There are any number of simple
experiments that can tell you whether or not a particular environment
has a significant effect on some metric of reproductive success.

You've recognized that "variants" exist. What mechanism explains this,
Darwin?

Darwin didn't know. But he did know, from his knowledge of artificial
selection, that new variants do arise in populations. That was common
knowledge of the time, certainly among naturalists, including Paley.
That was all he really needed to know: that it was a fact that
variation existed and a fact that new variation occurred and occurs in
populations.

That was all he needed to know for what? To explain variation?

No. As has been pointed out, variation in populations is a necessary
condition for natural selection to occur. No source of variation,
eventually no natural selection. One does not need to understand the
*mechanism* of variation (although we do now) to observe that
variation both exists and is produced from time to time in
populations.

You claimed that variation was all Darwin needed to know.

As you would know, if you had more brains than your typical soybean,
'natural selection' was an understood concept even before Darwin
recognized that it might be capable of transforming morphology
directionally as well as conserving morphology. Like all theories,
there are understood, by those with more brains than your typical
soybean, assumptions in the theory.

These are: 1) Populations of organisms have and produce 'variations'.
Some of this variation is not 'heritable'.
But some of the 'variation' is 'heritable'. We now understand that
the heritable portion of variation is ultimately due to mutation or
change in genes, but one does not need to know the mechanism or source
of heritable variation. All you need is knowledge that some variation
is heritable in nature and that sports and variants are produced in
nature. Darwin, as an animal breeder, was well aware that some traits
are, at least partly, heritable and that sports and variants do
appear. In fact, all the naturalists and even many simple farmers of
this time were aware of both the fact of the production of variants in
populations, the existence of variation in populations, and that some
of this variation is heritable.

2) Populations of organisms produce more progeny than survive or are
able to reproduce themselves. Again, this was hardly startling to the
naturalists of the time, be it Darwin or Paley. A good Christian
minister by the name of Malthus wrote about it extensively. Paley,
understandably, had some difficulty with reconciling this fact with
his belief that God is Good, although he, being a scientist of his
time, did not deny the fact.

3) Some variants (again, mostly morphological) are more likely to
survive than others in any particular environment. Again, any half-
way observant farmer of this time would have known this.

4) To the extent that the surviving variants do so because of the
'hereditary' nature of the variation, this changes the 'hereditary'
nature of the next generation.

This last point is where Darwin's vision of selection differs from
Paley's. To Paley, selection worked only to preserve a kind of
dynamic genetic stasis by removing 'differences' from the 'norm' of
the species. That is, selection, which Paley and other naturalists
knew existed and did not deny existed, was purely a conservative
feature of nature. This is understandable if you recognize that, on
the time-scale of humans, most organisms are already well-adapted to
the niches they fill. And, in fact, on a human time-scale, the
conservative nature of selection is the most obvious and
overwhelmingly observed aspect of selection.

But Darwin knew about, and understood, deep time. And in deep time,
environments change and niches open up. Under those conditions,
selection can be, indeed must be, directional for *particular*
features rather than merely conservative for *all* features of an
organism. That is where Darwin's genius lay. He laid out the
evidence that organisms have changed through deep time and provided a
mechanism (variation + selection) that would generate morphological
change of particular features in organisms. [What we now know is that
the amount of selective change in genes or the production of
'modified' or 'new' genes over even evolutionary time is really quite
small. Most of the genes in mammals are retained for function (the
conservative aspect of selection) in all mammals. Indeed, most of the
change observed in morphology represents not change in genes but
change in gene regulation in a quantitative and/or time-dependent
fashion.]

I assume you
mean to form a theory of "origin of species".
Wouldn't the mechanism he described, natural selection, be seen as the
cause of variation?

No. Natural selection works only on currently existing variation. It
does not produce variation. Natural selection does not work against
or in favor of *non-existent* variants. But, in order for natural
selection to work, there must be variants and thus a mechanism for
producing variants. Even in Darwin's time, even in Paley's time, it
was clear that variants both existed in populations and were being
generated. The difference between Darwin and Paley is that, for
Paley, natural selection was always and only conservative in nature.

That is, there are rather simple experimental tests that can determine
if a particular environment has a significant differential causal
impact on two variants. To take a simple example, mix together 50%
strep sensitive and 50% strep resistant bacteria and plate them in
growth media either with or without streptomycin. After growth,
determine the % strep resistant and strep sensitive cells and
determine if the difference is likely to be due to chance (or drift)
alone or requires a *causal* impact by the environment.

Please provide a reference to a similar experiment was performed by
Darwin, and what his conclusions were about mechansim.

As anyone will now tell you, Darwin worked with an erroneous mechanism
of inheritance (blending inheritance). That does not mean he was
wrong about variation existing in a population and variation arising
in populations. Knowledge of the details for how variation arises was
not necessary to understand how natural selection works.

Certainly a lack of knowledge does not provide a mechanism of
inheritance.
Describe how natural selection works without reference to a mechanism
of inheritance, Howard.

It is only necessary, for natural selection to work, that one be able
to recognize that there is some consistent mechanism of inheritance
(transmission of features from parents to offspring) in living
organisms. That knowledge already existed in Darwin's time, even
though an understanding of the precise mechanism did not. Although
more difficult in some ways, it is possible for natural selection to
work via Darwin's proposed mechanism of inheritance, wrong though it
was. But again, SFW. This is 2007, not 1857.

Oh no, variation of what exists isn't all thats needed. Shame.

It is *one* of the requirements. What makes you think it is the only
requirement other than your need for some sort of soybean quasi-
intelligent argument you can make?

It may
be possible for something you might attribute to "natural selection"
to occur in the absense of a source of "new variation", but could not
explain evolutionary change.

Well, assuming the variation is heritable, it would produce
evolutionary change right up to the point when there was no more
variation to work on. From that point, one must then wait for new
variation to appear for selection to work on. Of course, the new
variation will be occurring in a different context than the original
context.

I notice now that you appear to refer to natural selection as the
mechanism of inheritance. Is this wrong, or did you just not identify
this mechanism of inheritance?

Yes, that was a wrong interpretation. I did not refer to natural
selection as "the mechanism of inheritance". I said that for natural
selection to have an evolutionary impact, the variation must be, at
least in part, heritable, and thus there must be a mechanism of
heritability. But Darwin knew that there must be a mechanism of
heritabilty. He didn't know what it was. But he recognized that
heritability of traits occurred and was a 'fact of nature'. So did
Paley.

In other words, in what way is it possible to
understand how natural selection works, being aware of but lacking a
mechanism of inheritance, in order to claim an explanation of
variation, diversity, inheritance, speciation.

The underlying requirement for natural selection does not require a
correct understanding of the mechanisms of variation or inheritance.
It does require evidence and knowledge that variation in populations
and inheritance of traits exist. That information was available in
Darwin's time. The precise mechanisms of variation and inheritance
are quite fully (if not completely) known today. And the increased
knowledge of mechanisms has largely supported Darwinian ideas about
natural selection.

No, the information was not available in Darwin's time to explain the
cell in the little warm pond to frogs.

Enough information was available to propose the explanation of common
descent. At that time, not enough was present to claim that that
descent went all the way back to single cells in the pond. But now
there is enough evidence that all life presently on the earth has a
common origin. You might wish to argue that that common origin is due
to common design rather than branching history, but then you would
have to explain the traces of common history that are present without
invoking a deliberate deception by the designer.

And the observations that
existed of inheritance coupled with natural selection didn't explain
it, nor are they capable of explaining it by themselves even now.

Whistling past the graveyard.


.

Loading