This is my first installment in which I have tried to explain my position on
ID specifically the arguments furthered by Dembski and Behe. I will attempt
to show why I believe they have failed to make a compelling scientific case.
I would appreciate and encourage feedback that will allow me to improve my
arguments. I have used extensive quotation to support my argument. These
quotes are from mainly online resources.
Intelligent Design
In this essay I would like to address various arguments of design that have
been used by the Intelligent Design proponents. I will focus on Behe and
Dembski as they seem to be the ones who have made an attempt to apply a
scientific methodology to detect design.
General argument
ID identifies design, not the designer. This means that ID cannot exclude
natural forces as the intelligent agent of design.
Wesley Elsberry:
"The apparent, but unstated, logic behind the move from design to
agency can be given as follows:
1. There exists an attribute in common of some subset of objects
known to be designed by an intelligent agent.
2. This attribute is never found in objects known not to be designed
by an intelligent agent.
3. The attribute encapsulates the property of directed contingency
or choice.
4.For all objects, if this attribute is found in an object, then we
may conclude that the object was designed by an intelligent agent.
"This is an inductive argument. Notice that by the second step, one
must eliminate from consideration precisely those biological
phenomena which Dembski wishes to categorize. In order to conclude
intelligent agency for biological examples, the possibility that
intelligent agency is not operative is excluded a priori. One large
problem is that directed contingency or choice is not solely an
attribute of events due to the intervention of an intelligent agent.
The "actualization-exclusion-specification" triad mentioned above also
fits natural selection rather precisely. One might thus conclude that
Dembski's argument establishes that natural selection can be recognized
as an intelligent agent. "
http://inia.cls.org/~welsberr/zgists/wre/papers/dembski7.html
Behe
The argument for design
Behe argues that IC systems are a reliable indicator of design. How does he
reach this conlusion and more relevantly, does the conclusion follow
logically from his argument or from the evidence. Let's first see how Behe
defines IC:
"By irreducible complexity I mean a single system which is composed of
several interacting parts that contribute to the basic function, and
where the removal of any one of the parts causes the system to
effectively cease functioning.
An irreducibly complex system cannot be produced gradually by slight,
successive modifications of a precursor system, since any precursor to
an irreducibly complex system is by definition nonfunctional." [Behe]
From Behe's Empty Box (http://www.world-of-dawkins.com/box/behe.htm):
"But read this argument carefully. Behe is not offering a way to detect
design, he is offering a way to falsify gradual Darwinian evolution,
and by elimination, conclude design. But there is one big problem- his
falsifier has been falsified. The conclusion that an "irreducibly
complex system cannot be produced gradually by slight,
successive modifications of a precursor system" is simply wrong. "
Behe does admit that indirect natural pathways to IC systems may exist but
considers such pathways unlikely. However Behe does not provide us with an
argument to support his assertion.
"One can never completely rule out such an indirect route, which is
tantamount to proving a negative. However, the more complex the
system, the more difficult it becomes to envision such indirect
scenarios and the more examples of irreducible complexity we meet, the
less and less persuasive such indirect scenarios become. It cannot be
that everything in life started out as something else.
" Behe, "Intelligent design theory as a tool" , pp. 179
It is clear that there is a problem for IC/ID here, if natural pathways
cannot be excluded beforehand then IC is not a reliable detector
of design. We can perhaps for individual IC systems try to show that the
possibility of a Darwinian (or non-Darwinian) pathway is diminishlingly small
but ICness itself is not a sufficient indicator of design anymore.
Behe's new definition
"While I think that䴜s a reasonable definition of IC, and it gets across the
idea to a general audience, it has some drawbacks. It focuses on
already-completed systems, rather than on the process of trying to build a
system, as natural selection would have to do. It emphasizes ‰¥þparts,‰¥ÿ but
says nothing about the properties of the parts, how complex they are, or how
the parts get to be where they are. It speaks of ‰¥þparts that contribute to
the basic function‰¥ÿ, but that phrase can, and has, been interpreted in ways
other than what I had in mind (for example, talking about whole organs that
contribute to complex functions such as ‰¥þliving‰¥ÿ), muddying the waters in my
view. What‰¥ús more, the definition doesn‰¥út allow for ‰¥þdegree‰¥ÿ of irreducible
complexity; a system either has it or it doesn䴜t. Yet certainly some IC
systems are more complex than others; some seem more forbidding than others. "
[...]
"An irreducibly complex evolutionary pathway is one that contains one or more
unselected steps (that is, one or more necessary-but-unselected mutations).
The degree of irreducible complexity is the number of unselected steps in the
pathway. "
So now Behe admits that IC pathways exist. This makes ICness an unreliable
detector of design.
"That definition has the advantage of promoting research: to state clear,
detailed evolutionary pathways; to measure probabilistic resources; to
estimate mutation rates; to determine if a given step is selected or not. It
allows for the proposal of any evolutionary scenario a Darwinist (or others)
may wish to submit, asking only that it be detailed enough so that relevant
parameters might be estimated. If the improbability of the pathway exceeds
the available probabilistic resources (roughly the number of organisms over
the relevant time in the relevant phylogenetic branch) then Darwinism is
deemed an unlikely explanation and intelligent design a likely one. "
Here Behe merely restates what science has already been doing. But he seems
to suggest that one has to do this in order to prove or disprove an IC
evolutionary pathway. I am looking forward to ID'ers taking notice from Behe
and start producing some evidence that measures probabilistic resources,
estimates non evolutionary pathways and if the improbability of the pathway
exceeds the available probabilistic resources then ID is deemed an unlikely
one. But unlike Behe I will not make the leap of logic to suggest that this
would prove a Darwinian pathway.
Darwinian pathways and IC
Robison shows a natural pathway to an IC system
http://www.talkorigins.org/faqs/behe/review.html
Behe responds
"I argue that, while Robison䴜s scenario does indeed build a new step in
the cascade, it doesn䴜t do it by Darwinian means. Rather, it does so by
Robison䴜s intelligent direction. "
This makes for a poor argument. "By Robison's intelligent direction". Of
course an argument is always intelligently directed but does this mean that
since it does not do it by Darwinian means, it should be ID? That's exactly
the kind of false dichotomy that seems to be present in Behe's original
argument about IC systems.
[...]
"Thus his scenario postulates four successive, very specific steps:
1) gene duplication of the particular multi-talented enzyme;
2) the first loss of function step;
3) the second loss of function step;
4) a step to take advantage of the situation.
As Robison emphasized, the first three steps are neutral; that is,
they do the organism neither harm nor good. Only when the fourth
step is completed is there a selective advantage. Now, it must be
remembered that the Darwinian magic depends on natural selection.
If a trait is advantageous, it will take over a population, thus
providing a large base from which the next advantageous mutation
might arise. However, if a trait is neutral, providing no
advantage, it is far, far less likely to spread, so the odds of a
second mutation appearing that depends on the first are not
improved at all--they䴜re pretty much the same as luckily getting
the two specific mutations simultaneously. In the final analysis
Robison䴜s scenario is completely non-Darwinian. It postulates
an already-functioning system that wasn䴜t justified in Darwinian terms,
and it then goes through three neutral, non-selected steps. Only at the
very end is there a selectable property that wasn䴜t postulated at the
beginning."
From "In Defense of the Irreducibility of the Blood Clotting Cascade:
Response to Russell Doolittle, Ken Miller and Keith Robison", Michael J.
Behe, 2000.
Even if the scenario is not Darwinian, it still shows how natural processes
could lead to an IC system. If Behe wants to argue agains such scenarios for
each IC system then it is up to him to provide evidence that it did not
happen in the specific instance.
But did Robison conclude that neutral steps "do the organism neither harm nor
good". My reading of Robison suggests that he was talking about neutral with
respect to the system of interest. However this does not mean that the
mutation itself was neutral to the organism as a whole. Gene's often regulate
more than a single system and mutations in such genes could be neutral in
one but advantageous or detrimental in another.
For example:
"Hitch-hiking
disadvantageous or neutral alleles may be carried to fixation by
linkage to an advantageous allele for another gene might explain the
deficit in heterozygotes (neutral theory) "
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