If you ever contact anyone who thinks creationism has some validity, you might want to recommend that he or she read the following comments by an expert, John Rennie, editor-in-chief of SCIENTIFIC AMERICAN.

         [Opponents of evolution want to make a place for creationism by tearing down real science, but their arguments don't hold up.]

         When Charles Darwin introduced the theory of evolution through natural selection 143 years ago, the scientists of the day argued over it fiercely, but the massing evidence from paleontology, genetics, zoology, molecular biology and other fields gradually established evolution's truth beyond reasonable doubt.  Today that battle has been won
everywhere--except in the public imagination.  Embarrassingly, in the 21st century, in the most scientifically
advanced nation the world has ever known, creationists can still persuade politicians, judges and ordinary citizens that evolution is a flawed, poorly supported fantasy.  They lobby for creationist ideas such as "intelligent design" to be taught as alternatives to evolution in science classrooms.  As this article goes to press, the Ohio Board of Education is debating whether to mandate such a change.  Some antievolutionists, such as Philip E. Johnson, a law professor at the
University of California at Berkeley and author of Darwin on Trial, admit that they intend for intelligent-design theory to serve as a "wedge" for reopening science classrooms to discussions of God.  Besieged teachers and others may increasingly find themselves on the spot to defend evolution and refute creationism.  The arguments that creationists use are typically specious and based on misunderstandings of (or outright lies about) evolution, but the number and diversity of the objections can put even well-informed people at a disadvantage.  To help with answering them, the following list rebuts some of the most common "scientific" arguments raised against evolution.  It also directs
readers to further sources for information and explains why creation science has no place in the classroom.

Point #1.  Evolution is only a theory. It is not a fact or a scientific
law.

REPLY:  Many people learned in elementary school that a theory falls in
the middle of a hierarchy of certainty--above a mere hypothesis but
below a law.  Scientists do not use the terms that way, however.
According to the National Academy of Sciences (NAS), a scientific theory
is "a well-substantiated explanation of some aspect of the natural world
that can incorporate facts, laws, inferences, and tested hypotheses."
No amount of validation changes a theory into a law, which is a
descriptive generalization about nature.  So when scientists talk about
the theory of evolution--or the atomic theory or the theory of
relativity, for that matter--they are not expressing reservations about
its truth.
In addition to the theory of evolution, meaning the idea of descent
with modification, one may also speak of the fact of evolution.  The NAS
defines a fact as "an observation that has been repeatedly confirmed and
for all practical purposes is accepted as 'true.'"  The fossil record
and abundant other evidence testify that organisms have evolved through
time.  Although no one observed those transformations, the indirect
evidence is clear, unambiguous and compelling.  All sciences frequently
rely on indirect evidence.  Physicists cannot see subatomic particles
directly, for instance, so they verify their existence by watching for
telltale tracks that the particles leave in cloud chambers.  The absence
of direct observation does not make physicists' conclusions less
certain.

Point #2.  Evolution is unscientific, because it is not testable or
falsifiable. It makes claims about events that were not observed and can
never be re-created.

REPLY:  This blanket dismissal of evolution ignores important
distinctions that divide the field into at least two broad areas:
microevolution and macroevolution.  Microevolution looks at changes
within species over time--changes that may be preludes to speciation,
the origin of new species.  Macroevolution studies how taxonomic groups
above the level of species change.  Its evidence draws frequently from
the fossil record and DNA comparisons to reconstruct how various
organisms may be related.
These days even most creationists acknowledge that microevolution has
been upheld by tests in the laboratory (as in studies of cells, plants
and fruit flies) and in the field (as in Grant's studies of evolving
beak shapes among Galápagos finches).  Natural selection and other
mechanisms--such as chromosomal changes, symbiosis and
hybridization--can drive profound changes in populations over time.
The historical nature of macroevolutionary study involves inference
from fossils and DNA rather than direct observation.  Yet in the
historical sciences (which include astronomy, geology and archaeology,
as well as evolutionary biology), hypotheses can still be tested by
checking whether they accord with physical evidence and whether they
lead to verifiable predictions about future discoveries.  For instance,
evolution implies that between the earliest-known ancestors of humans
(roughly five million years old) and the appearance of anatomically
modern humans (about 100,000 years ago), one should find a succession of
hominid creatures with features progressively less apelike and more
modern, which is indeed what the fossil record shows.  But one should
not--and does not--find modern human fossils embedded in strata from the
Jurassic period (144 million years ago).  Evolutionary biology routinely
makes predictions far more refined and precise than this, and
researchers test them constantly.
Evolution could be disproved in other ways, too.  If we could document
the spontaneous generation of just one complex life-form from inanimate
matter, then at least a few creatures seen in the fossil record might
have originated this way.  If superintelligent aliens appeared and
claimed credit for creating life on earth (or even particular species),
the purely evolutionary explanation would be cast in doubt.  But no one
has yet produced such evidence.
It should be noted that the idea of falsifiability as the defining
characteristic of science originated with philosopher Karl Popper in the
1930s.  More recent elaborations on his thinking have expanded the
narrowest interpretation of his principle precisely because it would
eliminate too many branches of clearly scientific endeavor.

Point #3.  Increasingly, scientists doubt the truth of evolution.

REPLY:  No evidence suggests that evolution is losing adherents.  Pick
up any issue of a peer-reviewed biological journal, and you will find
articles that support and extend evolutionary studies or that embrace
evolution as a fundamental concept.  Conversely, serious scientific
publications disputing evolution are all but nonexistent.  In the
mid-1990s George W. Gilchrist of the University of Washington surveyed
thousands of journals in the primary literature, seeking articles on
intelligent design or creation science.  Among those hundreds of
thousands of scientific reports, he found none.  In the past two years,
surveys done independently by Barbara Forrest of Southeastern Louisiana
University and Lawrence M. Krauss of Case Western Reserve University
have been similarly fruitless.
Creationists retort that a closed-minded scientific community rejects
their evidence.  Yet according to the editors of Nature, Science and
other leading journals, few antievolution manuscripts are even
submitted.  Some antievolution authors have published papers in serious
journals.  Those papers, however, rarely attack evolution directly or
advance creationist arguments; at best, they identify certain
evolutionary problems as unsolved and difficult (which no one
disputes).  In short, creationists are not giving the scientific world
good reason to take them seriously.

Point #4.  The disagreements among even evolutionary biologists show
how little solid science supports evolution.

REPLY:  Evolutionary biologists passionately debate diverse topics: how
speciation happens, the rates of evolutionary change, the ancestral
relationships of birds and dinosaurs, whether Neandertals were a species
apart from modern humans, and much more.  These disputes are like those
found in all other branches of science.  Acceptance of evolution as a
factual occurrence and a guiding principle is nonetheless universal in
biology.
Unfortunately, dishonest creationists have shown a willingness to take
scientists' comments out of context to exaggerate and distort the
disagreements.  Anyone acquainted with the works of paleontologist
Stephen Jay Gould of Harvard University knows that in addition to
co-authoring the punctuated-equilibrium model, Gould was one of the most
eloquent defenders and articulators of evolution.  (Punctuated
equilibrium explains patterns in the fossil record by suggesting that
most evolutionary changes occur within geologically brief
intervals--which may nonetheless amount to hundreds of generations.)
Yet creationists delight in dissecting out phrases from Gould's
voluminous prose to make him sound as though he had doubted evolution,
and they present punctuated equilibrium as though it allows new species
to materialize overnight or birds to be born from reptile eggs.  When
confronted with a quotation from a scientific authority that seems to
question evolution, insist on seeing the statement in context.  Almost
invariably, the attack on evolution will prove illusory.

Point #5.  If humans descended from monkeys, why are there still
monkeys?

REPLY:  This surprisingly common argument reflects several levels of
ignorance about evolution.  The first mistake is that evolution does not
teach that humans descended from monkeys; it states that both have a
common ancestor.
The deeper error is that this objection is tantamount to asking, "If
children descended from adults, why are there still adults?"  New
species evolve by splintering off from established ones, when
populations of organisms become isolated from the main branch of their
family and acquire sufficient differences to remain forever distinct.
The parent species may survive indefinitely thereafter, or it may become
extinct.

Point #6.  Evolution cannot explain how life first appeared on earth.

REPLY:  The origin of life remains very much a mystery, but biochemists
have learned about how primitive nucleic acids, amino acids and other
building blocks of life could have formed and organized themselves into
self-replicating, self-sustaining units, laying the foundation for
cellular biochemistry.  Astrochemical analyses hint that quantities of
these compounds might have originated in space and fallen to earth in
comets, a scenario that may solve the problem of how those constituents
arose under the conditions that prevailed when our planet was young.
Creationists sometimes try to invalidate all of evolution by pointing
to science's current inability to explain the origin of life.  But even
if life on earth turned out to have a nonevolutionary origin (for
instance, if aliens introduced the first cells billions of years ago),
evolution since then would be robustly confirmed by countless
microevolutionary and macroevolutionary studies.

Point #7.  Nobody has ever seen a new species evolve.

REPLY:  Speciation is probably fairly rare and in many cases might take
centuries.  Furthermore, recognizing a new species during a formative
stage can be difficult, because biologists sometimes disagree about how
best to define a species.  The most widely used definition, Mayr's
Biological Species Concept, recognizes a species as a distinct community
of reproductively isolated populations--sets of organisms that normally
do not or cannot breed outside their community.  In practice, this
standard can be difficult to apply to organisms isolated by distance or
terrain or to plants (and, of course, fossils do not breed).  Biologists
therefore usually use organisms' physical and behavioral traits as clues
to their species membership.
Nevertheless, the scientific literature does contain reports of
apparent speciation events in plants, insects and worms.  In most of
these experiments, researchers subjected organisms to various types of
selection--for anatomical differences, mating behaviors, habitat
preferences and other traits--and found that they had created
populations of organisms that did not breed with outsiders.  For
example, William R. Rice of the University of New Mexico and George W.
Salt of the University of California at Davis demonstrated that if they
sorted a group of fruit flies by their preference for certain
environments and bred those flies separately over 35 generations, the
resulting flies would refuse to breed with those from a very different
environment.
 
 

Point #8.  The Second Law of Thermodynamics says that systems must
become more disordered over time.  Living cells therefore could not have
evolved from inanimate chemicals, and multicellular life could not have
evolved from protozoa.

REPLY:  This argument derives from a misunderstanding of the Second
Law.  If it were valid, mineral crystals and snowflakes would also be
impossible, because they, too, are complex structures that form
spontaneously from disordered parts.
The Second Law actually states that the total entropy of a closed
system (one that no energy or matter leaves or enters) cannot decrease.
Entropy is a physical concept often casually described as disorder, but
it differs significantly from the conversational use of the word.
More important, however, the Second Law permits parts of a system to
decrease in entropy as long as other parts experience an offsetting
increase.  Thus, our planet as a whole can grow more complex because the
sun pours heat and light onto it, and the greater entropy associated
with the sun's nuclear fusion more than rebalances the scales.  Simple
organisms can fuel their rise toward complexity by consuming other forms
of life and nonliving materials.

Point #9.  Evolutionists cannot point to any transitional
fossils--creatures that are half reptile and half bird, for instance.

REPLY:  Actually, paleontologists know of many detailed examples of
fossils intermediate in form between various taxonomic groups.  One of
the most famous fossils of all time is Archaeopteryx, which combines
feathers and skeletal structures peculiar to birds with features of
dinosaurs.  A flock's worth of other feathered fossil species, some more
avian and some less, has also been found.  A sequence of fossils spans
the evolution of modern horses from the tiny Eohippus.  Whales had
four-legged ancestors that walked on land, and creatures known as
Ambulocetus and Rodhocetus helped to make that transition [see "The
Mammals That Conquered the Seas," by Kate Wong; Scientific American,
May].  Fossil seashells trace the evolution of various mollusks through
millions of years.  Perhaps 20 or more hominids (not all of them our
ancestors) fill the gap between Lucy the australopithecine and modern
humans.
Creationists, though, dismiss these fossil studies. They argue that
Archaeopteryx is not a missing link between reptiles and birds--it is
just an extinct bird with reptilian features.  They want evolutionists
to produce a weird, chimeric monster that cannot be classified as
belonging to any known group.  Even if a creationist does accept a
fossil as transitional between two species, he or she may then insist on
seeing other fossils intermediate between it and the first two.  These
frustrating requests can proceed ad infinitum and place an unreasonable
burden on the always incomplete fossil record.
Nevertheless, evolutionists can cite further supportive evidence from
molecular biology.  All organisms share most of the same genes, but as
evolution predicts, the structures of these genes and their products
diverge among species, in keeping with their evolutionary
relationships.  Geneticists speak of the "molecular clock" that records
the passage of time.  These molecular data also show how various
organisms are transitional within evolution.

Point #10.  Living things have fantastically intricate features--at the
anatomical, cellular and molecular levels--that could not function if
they were any less complex or sophisticated.  The only prudent
conclusion is that they are the products of intelligent design, not
evolution.

REPLY:  This "argument from design" is the backbone of most recent
attacks on evolution, but it is also one of the oldest.  In 1802
theologian William Paley wrote that if one finds a pocket watch in a
field, the most reasonable conclusion is that someone dropped it, not
that natural forces created it there.  By analogy, Paley argued, the
complex structures of living things must be the handiwork of direct,
divine invention.  Darwin wrote On the Origin of Species as an answer to
Paley: he explained how natural forces of selection, acting on inherited
features, could gradually shape the evolution of ornate organic
structures.
Generations of creationists have tried to counter Darwin by citing the
example of the eye as a structure that could not have evolved.  The
eye's ability to provide vision depends on the perfect arrangement of
its parts, these critics say.  Natural selection could thus never favor
the transitional forms needed during the eye's evolution--what good is
half an eye?  Anticipating this criticism, Darwin suggested that even
"incomplete" eyes might confer benefits (such as helping creatures
orient toward light) and thereby survive for further evolutionary
refinement.  Biology has vindicated Darwin: researchers have identified
primitive eyes and light-sensing organs throughout the animal kingdom
and have even tracked the evolutionary history of eyes through
comparative genetics.  (It now appears that in various families of
organisms, eyes have evolved independently.)
Today's intelligent-design advocates are more sophisticated than their
predecessors, but their arguments and goals are not fundamentally
different.  They criticize evolution by trying to demonstrate that it
could not account for life as we know it and then insist that the only
tenable alternative is that life was designed by an unidentified
intelligence.

Point #11.  Recent discoveries prove that even at the microscopic
level, life has a quality of complexity that could not have come about
through evolution.

REPLY:  "Irreducible complexity" is the battle cry of Michael J. Behe
of Lehigh University, author of Darwin's Black Box: The Biochemical
Challenge to Evolution.  As a household example of irreducible
complexity, Behe chooses the mousetrap--a machine that could not
function if any of its pieces were missing and whose pieces have no
value except as parts of the whole.  What is true of the mousetrap, he
says, is even truer of the bacterial flagellum, a whiplike cellular
organelle used for propulsion that operates like an outboard motor.  The
proteins that make up a flagellum are uncannily arranged into motor
components, a universal joint and other structures like those that a
human engineer might specify.  The possibility that this intricate array
could have arisen through evolutionary modification is virtually nil,
Behe argues, and that bespeaks intelligent design.  He makes similar
points about the blood's clotting mechanism and other molecular systems.

Yet evolutionary biologists have answers to these objections.  First,
there exist flagellae with forms simpler than the one that Behe cites,
so it is not necessary for all those components to be present for a
flagellum to work.  The sophisticated components of this flagellum all
have precedents elsewhere in nature, as described by Kenneth R. Miller
of Brown University and others.  In fact, the entire flagellum assembly
is extremely similar to an organelle that Yersinia pestis, the bubonic
plague bacterium, uses to inject toxins into cells.
The key is that the flagellum's component structures, which Behe
suggests have no value apart from their role in propulsion, can serve
multiple functions that would have helped favor their evolution.  The
final evolution of the flagellum might then have involved only the novel
recombination of sophisticated parts that initially evolved for other
purposes.  Similarly, the blood-clotting system seems to involve the
modification and elaboration of proteins that were originally used in
digestion, according to studies by Russell F. Doolittle of the
University of California at San Diego.  So some of the complexity that
Behe calls proof of intelligent design is not irreducible at all.
Complexity of a different kind--"specified complexity"--is the
cornerstone of the intelligent-design arguments of William A. Dembski of
Baylor University in his books The Design Inference and No Free Lunch.
Essentially his argument is that living things are complex in a way that
undirected, random processes could never produce.  The only logical
conclusion, Dembski asserts, in an echo of Paley 200 years ago, is that
some superhuman intelligence created and shaped life.
Dembski's argument contains several holes.  It is wrong to insinuate
that the field of explanations consists only of random processes or
designing intelligences.  Researchers into nonlinear systems and
cellular automata at the Santa Fe Institute and elsewhere have
demonstrated that simple, undirected processes can yield extraordinarily
complex patterns.  Some of the complexity seen in organisms may
therefore emerge through natural phenomena that we as yet barely
understand.  But that is far different from saying that the complexity
could not have arisen naturally.
"Creation science" is a contradiction in terms.  A central tenet of
modern science is methodological naturalism--it seeks to explain the
universe purely in terms of observed or testable natural mechanisms.
Thus, physics describes the atomic nucleus with specific concepts
governing matter and energy, and it tests those descriptions
experimentally.  Physicists introduce new particles, such as quarks, to
flesh out their theories only when data show that the previous
descriptions cannot adequately explain observed phenomena.  The new
particles do not have arbitrary properties, moreover--their definitions
are tightly constrained, because the new particles must fit within the
existing framework of physics.
In contrast, intelligent-design theorists invoke shadowy entities that
conveniently have whatever unconstrained abilities are needed to solve
the mystery at hand.  Rather than expanding scientific inquiry, such
answers shut it down.  (How does one disprove the existence of
omnipotent intelligences?)  Intelligent design offers few answers.  For
instance, when and how did a designing intelligence intervene in life's
history?  By creating the first DNA?  The first cell?  The first human?
Was every species designed, or just a few early ones?  Proponents of
intelligent-design theory frequently decline to be pinned down on these
points.  They do not even make real attempts to reconcile their
disparate ideas about intelligent design.  Instead they pursue argument
by exclusion--that is, they belittle evolutionary explanations as
far-fetched or incomplete and then imply that only design-based
alternatives remain.
Logically, this is misleading: even if one naturalistic explanation is
flawed, it does not mean that all are.  Moreover, it does not make one
intelligent-design theory more reasonable than another.  Listeners are
essentiallyleft to fill in the blanks for themselves, and some
willundoubtedly do so by substituting their religious beliefs for
scientific ideas.
Time and again, science has shown that methodological naturalism can
push back ignorance, finding increasingly detailed and informative
answers to mysteries that once seemed impenetrable: the nature of light,
the causes of disease, how the brain works.  Evolution is doing the same
with the riddle of how the living world took shape.  Creationism, by any
name, adds nothing of intellectual value to the effort.

Point #12.  Mathematically, it is inconceivable that anything as
complex as a protein, let alone a living cell or a human, could spring
up by chance.

REPLY:  Chance plays a part in evolution (for example, in the random
mutations that can give rise to new traits), but evolution does not
depend on chance to create organisms, proteins or other entities.  Quite
the opposite: natural selection, the principal known mechanism of
evolution, harnesses nonrandom change by preserving "desirable"
(adaptive) features and eliminating "undesirable" (nonadaptive) ones.
As long as the forces of selection stay constant, natural selection can
push evolution in one direction and produce sophisticated structures in
surprisingly short times.
As an analogy, consider the 13-letter sequence "TOBEORNOTTOBE."  Those
hypothetical million monkeys, each pecking out one phrase a second,
could take as long as 78,800 years to find it among the 2613 sequences
of that length. But in the 1980s Richard Hardison of Glendale College
wrote a computer program that generated phrases randomly while
preserving the positions of individual letters that happened to be
correctly placed (in effect, selecting for phrases more like Hamlet's).
On average, the program re-created the phrase in just 336 iterations,
less than 90 seconds.  Even more amazing, it could reconstruct
Shakespeare's entire play in just four and a half days.

Point #13.  Natural selection might explain microevolution, but it
cannot explain the origin of new species and higher orders of life.

REPLY:  Evolutionary biologists have written extensively about how
natural selection could produce new species.  For instance, in the model
called allopatry, developed by Ernst Mayr of Harvard University, if a
population of organisms were isolated from the rest of its species by
geographical boundaries, it might be subjected to different selective
pressures.  Changes would accumulate in the isolated population.  If
those changes became so significant that the splinter group could not or
routinely would not breed with the original stock, then the splinter
group would be reproductively isolated and on its way toward becoming a
new species.
Natural selection is the best studied of the evolutionary mechanisms,
but biologists are open to other possibilities as well.  Biologists are
constantly assessing the potential of unusual genetic mechanisms for
causing speciation or for producing complex features in organisms.  Lynn
Margulis of the University of Massachusetts at Amherst and others have
persuasively argued that some cellular organelles, such as the
energy-generating mitochondria, evolved through the symbiotic merger of
ancient organisms.  Thus, science welcomes the possibility of evolution
resulting from forces beyond natural selection.  Yet those forces must
be natural; they cannot be attributed to the actions of mysterious
creative intelligences whose existence, in scientific terms, is
unproved.

Point #14.  Natural selection is based on circular reasoning: the
fittest are those who survive, and those who survive are deemed fittest.

REPLY:  "Survival of the fittest" is a conversational way to describe
natural selection, but a more technical description speaks of
differential rates of survival and reproduction.  That is, rather than
labeling species as more or less fit, one can describe how many
offspring they are likely to leave under given circumstances.  Drop a
fast-breeding pair of small-beaked finches and a slower-breeding pair of
large-beaked finches onto an island full of food seeds.  Within a few
generations the fast breeders may control more of the food resources.
Yet if large beaks more easily crush seeds, the advantage may tip to the
slow breeders.  In a pioneering study of finches on the Galápagos
Islands, Peter R. Grant of Princeton University observed these kinds of
population shifts in the wild
  [see his article "Natural Selection and Darwin's Finches"; Scientific
American, October 1991].
The key is that adaptive fitness can be defined without reference to
survival: large beaks are better adapted for crushing seeds,
irrespective of whether that trait has survival value under the
circumstances.

Point #15.  Mutations are essential to evolution theory, but mutations
can only eliminate traits.  They cannot produce new features.

REPLY:  On the contrary, biology has catalogued many traits produced by
point mutations (changes at precise positions in an organism's
DNA)--bacterial resistance to antibiotics, for example.  Mutations that
arise in the homeobox (Hox) family of development-regulating genes in
animals can also have complex effects.  Hox genes direct where legs,
wings, antennae and body segments should grow.  In fruit flies, for
instance, the mutation called Antennapedia causes legs to sprout where
antennae should grow.  These abnormal limbs are not functional, but
their existence demonstrates that genetic mistakes can produce complex
structures, which natural selection can then test for possible uses.
Moreover, molecular biology has discovered mechanisms for genetic
change that go beyond point mutations, and these expand the ways in
which new traits can appear. Functional modules within genes can be
spliced together in novel ways.  Whole genes can be accidentally
duplicated in an organism's DNA, and the duplicates are free to mutate
into genes for new, complex features.  Comparisons of the DNA from a
wide variety of organisms indicate that this is how the globin family of
blood proteins evolved over millions of years.
 

DOES AN OBJECTIVE LOOK AT THE HUMAN EYE SHOW EVIDENCE OF CREATION?

A frequently raised criticism of evolution in any evolution-creation
debate is that of the human eye.  The creationist will say something
like, "How can something as marvelous as the human eye have come about
by chance alone?  Surely there must have been a divine creation."  These
types of statements show two things.  First, the creationist doesn't
understand how evolution's 'chance' works. (i.e., They have yet to grasp
the concepts behind cumulative natural selection.)  Second, they haven't
bothered to really examine the human eye to look for characteristics
such as design flaws.

As Frank Zindler (former professor of biology and geology) stated,

          "As an organ developed via the opportunistic twists and turns
of evolutionary processes, the human eye is explainable.  As an organ
designed and created by an infinitely wise deity, the human eye is
inexcusable.  For unlike the invertebrate eyes ..., the human eye is
constructed upon the foundation of an almost incredible error: The
retina has been put together backwards!  Unlike the retinas of octopuses
and squids, in which the light-gathering cells are aimed forward, toward
the source of incoming light, the photoreceptor cells (the so called
rods and cones) of the human retina are aimed backward, away from the
light source.  Worse yet, the nerve fibers which must carry signals from
the retina to the brain must pass in front of the receptor cells,
partially impeding the penetration of light to the receptors.  Only a
blasphemer would attribute such a situation to divine design!
Although the human eye would be a scandal if it were the result of
divine deliberation, a plausible evolutionary explanation of its absurd
construction can be obtained quite easily--even though we can make
little use of paleontology (because eyes, like all soft tissues, rarely
fossilize)."

Biologist George Williams wrote an entire book on the subject of design
and purpose in nature.  Near the beginning of ‘The Pony Fish's Glow,’
Williams responds to Paley's watchmaker argument using various body
parts as examples of why Paley's argument may look good on the surface,
but it lacks
credibility when closely examined using modern technology and biology.
Here he discusses the human eye:
          "Not all features of the human eye make functional sense.
Some are arbitrary.  To begin at the grossest level, is there a good
functional reason for having two eyes?  Why not one or three or some
other number?  Yes, there is a reason: two is better than one because
they permit stereoscopic vision and the gathering of three-dimensional
information about the environment.  But three would be better still.  We
could have our stereoscopic view of what lies ahead plus another eye to
warn us of what might be sneaking up behind.  (I have more suggestions
for improving human vision in chapter 7.)  When we examine each eye from
behind, we find that there are six tiny muscles that move it so that it
can point in different directions.  Why six?  Properly spaced and
coordinated, three would suffice, just as three is an adequate number of
legs for a photographer's tripod.  The paucity of eyes and excess of
their muscles seem to have no functional explanation.
And some eye features are not merely arbitrary but clearly
dysfunctional.  The nerve fibers from the retinal rods and cones extend
not inward toward the brain but outward toward the chamber of the eye
and source of light.  They have to gather into a bundle, the optic
nerve, inside the eye, and exit via a hole in the retina.  Even though
the obstructing layer is microscopically thin, some light is lost from
having to pass through the layer of nerve fibers and ganglia and
especially the blood vessels that serve them. The eye is blind where the
optic nerve exits through its hole.  The loose application of the retina
to the underlying sclera makes the eye vulnerable to the serious medical
problem of detached retina.  It would not be if the nerve fibers passed
through the sclera and formed the optic nerve behind the eye. This
functionally sensible arrangement is in fact what is found in the eye of
a squid and other mollusks, but our eyes, and those of all other
vertebrates, have the functionally stupid upside-down orientation of the
retina.
Paley did not really confront this problem.  Little was known about
mollusks' eyes at the time, and Paley merely treated the blind spots as
one of the problems the eye must solve.  He correctly noted that the
medial position of the optic nerve exits avoids having both eyes blind
to the same part of the visual field.  Everything in the field is seen
by at least one eye.  It might also be claimed that the obstructing
tissues of the retina are made as thin and transparent as possible, so
as to minimize the shading of the light-sensitive layer.  Unfortunately
there is no way to make red blood cells transparent, and the blood
vessels cast demonstrable shadows.
What might Paley's reaction have been to the claim, which I will
elaborate in the next chapter, that mundane processes taking place
throughout living nature can produce contrivances without contrivers,
and that these processes produce not only functionally elegant features
but also, as a kind of cumulative historical burden, the arbitrary and
dysfunctional features of organisms?" (page 9-10)

He continues on the eye later as follows:
"What would Paley's reaction have been to the suggestion that the
creator's wisdom is as finite as ours, and that the engineering
perfection of such instruments as the eye...depends...on much
trial-and-error tinkering that supplemented the creator's limited
understanding?  And what about the suggestion that the creator had no
understanding at all, but accomplished sophisticated engineering
entirely on the basis of trial and error?" (pages 11-12)

Williams concludes his section on trial-and-error and the eye argument
with the following:
"This is no doubt true of all the implements we use: cameras, cars,
computers, and even the watch that Paley reasoned must have had an
intelligent designer.  How far is it possible to go with trial and error
alone?  All the way to the human eye and hand and immune system and all
the other well-engineered machinery by which we, and all other
organisms, solve the problems of life...

          Darwin was challenged repeatedly on this matter.  Critics
would point to the precision and design features of the eye and claim
that an organ of this perfection could not possibly have been produced
by an accumulation of small changes, each of which made the eye work
slightly better.  A grossly imperfect eye, which could be improved by
this process, would supposedly never evolve in the first place.  Slight
improvements in one part, such as the retina, would be useless without
an exactly matching improvement in another, such as an increased
precision of the lens.  This is an utterly fallacious kind of
reasoning.  An improved retina may be useless without an improved lens,
but both retinas and lenses are subject to individual variation.  Some
of the better retinas would be found in individuals who also had better
lenses, so that the improvements, on average, could be favored.

          The criticisms were also factually erroneous, and their
proponents were ignorant of biology.  As Darwin pointed out, familiarity
with the animal kingdom shows the existence today of just about every
stage in a plausible sequence from primitive light-sensitive cells on
the surfaces of tiny wormlike animals, through the rudimentary camera
eyes of scallops, to the advanced  optical instrumentation of squids and
vertebrates.  Every stage in this sequence is subject to variation, and
every stage is clearly useful to its possessor." (pages 13-14)

Another creature to consider is the mole rat.  Which theory holds water
when the eye of the mole rat is considered?  The ancestor of the mole
rat presumably used its eyes as it lived above ground and needed them
for survival.  However, the mole rat has adapted to living underground
in complete darkness.  Its eyes have become useless--indeed, they have
been buried beneath skin and fur and couldn't be used even if the mole
rat came into the light.  The neurons that were used for sight have been
put to better use in the mole rat's brain for other sensory functions.
Evolution by natural
selection perfectly explains the eyes of a mole rat.  A creationist must
resort to faith and/or a poor designer. (See Lucy's Legacy p. 25 and
Jared Diamond's "Competition for brain space" in Nature 382: 756-757.)

Those interested in this subject should also see chapters four and five
of Richard Dawkins' Climbing Mount Improbable, section 13.3 in Mark
Ridley's ‘Evolution,’ pages 110 to 114 in Cells, Embryos, and Evolution,
the faulty deductive reasoning of Paley--especially as it relates to
intelligent design inference for human eyes--from pages 140-143 of
‘Science As a Way of Knowing,’ The Foundations of Modern Biology, Ted
Gaten's research interests, the section entitled Eyes and Evolution on
pages 161-165 of ‘Songs, Roars, and Rituals, Evolution of the Eye and
Visual System’ by J. R. Cronly-Dillon and R. L. Gregory, and ‘How Could
An Eye Evolve?’  On a related topic, see the inefficiencies created by
natural selection (and lack of design) as illustrated on this page.

In summary, the eye not only lacks evidence of divine creation, it
exemplifies the problems that natural evolution can create (along with
the virtues) in organisms.  Rather than being a chief argument for
creationism,
the human eye should be a topic that 'special creation' and/or
'intelligent design hypothesis' apologists avoid.

Have a good day,

Dennis

PS.  The attached cartoon is an excellent synopsis of the situation.
Also notice that the Creationists have no lab with testing equipment,
artifacts, bones, etc.  Just a book.