Encyclopedia of Evolution.pdf - Online Reading Center

intelligent design
However, ID theorists like to distance themselves from oldfashioned
creationism.
The most popular statement of this position has been
Darwin’s Black Box, by Michael J. Behe, a biochemist at
Lehigh University. Most of the following discussion is based
upon Behe’s book.
According to Behe, gone from ID are all the arguments
that creationists usually present about gaps in the fossil
record, young age of the Earth, and the Flood of Noah.
Although most adherents of ID accept many or all of the
tenets of creationism (for example, Jay W. Richards, a senior
fellow at the Discovery Institute in Seattle, Wash., still uses
the “gaps in the fossil record” argument), the debate sidesteps
these issues. Few ID theorists accept the historical facts
of human evolution; but their publications generally do not
address it. Instead, it is enough for them to point out that
human (and other) biochemistry is too complex to have arisen
by evolution. Evolutionary scientists point out that the fossil
record really does provide evidence that evolution occurred;
Behe indicates that paleontology does not matter. Evolutionary
scientists, starting with Darwin (see appendix, “Darwin’s
‘One Long Argument’: A Summary of Origin of Species”)
and continuing through modern evolutionary scientists (see
Dawkins, Richard), point out the existence of intermediate
stages in the evolution of the eye from the simple eyespot of
a protozoan; Behe indicates that does not matter either. In his
discussion of the bombardier beetle, Behe admits that other
beetles have similar, and simpler, systems of defense; not surprisingly,
Behe indicates that this does not matter either. All
that matters, in his argument, is irreducible complexity on the
biochemical and cellular level. Behe’s examples of irreducibly
complex systems include vision in a retinal cell; the explosive
defense mechanism of the bombardier beetle; cilia and flagella
(the whiplike mechanisms by which many single-celled organisms
propel themselves); blood clot formation; and the mammalian
immune response.
According to ID arguments, in order for evolution to
produce biochemical complexity, uncountable billions of cells
would have to die over the course of billions of years. As a
matter of fact, that is exactly what happened during Precambrian
time. Almost 80 percent of evolutionary history
occurred when life on Earth was primarily microbial. It looks
from the Precambrian fossil record as if nothing much was
happening, but this is because the significant events were taking
place on a molecular scale that no fossil could reveal.
ID has two components, and there are major problems
with both. First, there is the recognition of “irreducible complexity.”
The recognition of irreducible complexity involves a
fallacy that Richard Dawkins has called “the argument from
personal incredulity.” Ever since the design argument in the
early 19th century (see natural theology), creationists have
argued that “I do not see how this could have evolved, therefore
it could not have evolved.” ID theory has simply continued
this argument, at a biochemical and cellular level. This is
no more convincing than when atheists claim, “I do not see
how there could be a God, therefore God does not exist.”
In fact, Behe’s argument is what could be called “the
argument from personal omniscience.” It takes three forms:
• Behe makes it sound as if he assumes the omniscience of
famous biochemists. Behe points out that Stanley Miller (see
Miller, Stanley) has been doing origin-of-life simulations
since 1953, the Journal of Molecular Evolution has been in
print since 1971, and the most prominent biochemists in
the world after all these years still have not figured out how
complex systems might have evolved by gradual steps. Surely,
if Stanley Miller cannot figure it out, then it could not have
happened—which assumes the omniscience of Stanley Miller.
• Although Behe does not really consider himself omniscient,
he did claim that ID theory (which everyone associates with
him) is as important a contribution to science as anything
contributed by Newton or Einstein.
• Behe makes it sound as if his readers are also omniscient.
He describes a complex biochemical system, then he asks
readers if they can imagine how it could have evolved in
gradual steps. If they cannot, then it could not have happened
that way.
Behe and other ID theorists also recognize irreducible
complexity on the basis of biochemical and cellular systems
as they now exist. They claim that simpler biochemical systems
would not work, and would be of no use to the organisms
even if they did:
• Behe cites the flagella of some eukaryotic cells as an example
of irreducible complexity. However, there are some
eukaryotic cells whose flagella lack one or more components
yet still function. The sperm of eels, for example,
lacks the central axis found in most eukaryotic flagella.
• Behe simply asserts that a system simpler than the irreducibly
complex ones would be of no use to an organism. He
uses the human immune system as an example. However,
the phytoalexin response, by which plants fend off infection
by fungi, is much simpler, and quite useful to the plant.
Behe even cites an article by David Baltimore regarding the
simpler, but still very effective, immune response of sharks,
then disregards it.
• Behe overlooks the possibility that intermediate structures
may have arisen as exaptations, having been useful for
some other purpose than that which they now serve (see
adaptation).
Second, ID has difficulty with the process by which complexity
has been generated. ID theorists usually insist that the
only two alternatives for explaining what they call irreducible
complexity is either gradual evolution or intelligent design,
both from scratch. Problems with this approach include:
• Substitutability of components of systems. One creationist
book from before the ID era, entitled Evolution: Possible
or Impossible?, made arguments such as this: living cells
use 20 different kinds of amino acids; the insulin protein
has 51 amino acid residues, therefore the chances against
the random origin of insulin are 20 51 . The chance of one in
20 51 essentially represents impossibility. Therefore, an insulin
molecule could not have evolved in a single step. However,
no evolutionary scientist believes that insulin arose in
a single step. In addition, not all 51 amino acids have to