[Paleopsych] Jerry Coyne: The Faith That Dare Not Speak Its Name

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Jerry Coyne: The Faith That Dare Not Speak Its Name
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    THE CASE AGAINST INTELLIGENT DESIGN.
    Post date: 08.11.05
    Issue date: 08.22.05

    Of Pandas and People
    By Percival Davis and Dean H. Kenyon
    (Haughton Publishing Company, 170 pp., $24.95)

    I.

    Exactly eighty years after the Scopes "monkey trial" in Dayton,
    Tennessee, history is about to repeat itself. In a courtroom in
    Harrisburg, Pennsylvania in late September, scientists and
    creationists will square off about whether and how high school
    students in Dover, Pennsylvania will learn about biological evolution.
    One would have assumed that these battles were over, but that is to
    underestimate the fury (and the ingenuity) of creationists scorned.

    The Scopes trial of our day--Kitzmiller, et al v. Dover Area School
    District et al--began innocuously. In the spring of 2004, the
    district's textbook review committee recommended that a new commercial
    text replace the outdated biology book. At a school board meeting in
    June, William Buckingham, the chair of the board's curriculum
    committee, complained that the proposed replacement book was "laced
    with Darwinism." After challenging the audience to trace its roots
    back to a monkey, he suggested that a more suitable textbook would
    include biblical theories of creation. When asked whether this might
    offend those of other faiths, Buckingham replied, "This country wasn't
    founded on Muslim beliefs or evolution. This country was founded on
    Christianity and our students should be taught as such." Defending his
    views a week later, Buckingham reportedly pleaded: "Two thousand years
    ago, someone died on a cross. Can't someone take a stand for him?" And
    he added: "Nowhere in the Constitution does it call for a separation
    of church and state."

    After a summer of heated but inconclusive wrangling, on October 18,
    2004 the Dover school board passed, by a vote of six to three, a
    resolution that read: "Students will be made aware of gaps/problems in
    Darwin's theory and of other theories of evolution including, but not
    limited to, intelligent design. Note: Origins of Life is not taught."
    A month later, the Dover school district issued a press release
    revealing how the alternative of "intelligent design" was to be
    presented. Before starting to teach evolution, biology teachers were
    to read their ninth-grade students a statement, which included the
    following language:

      The Pennsylvania Academic Standards require students to learn about
      Darwin's Theory of Evolution and eventually to take a standardized
      test of which evolution is a part.
      Because Darwin's Theory is a theory, it continues to be tested as
      new evidence is discovered. The Theory is not a fact. Gaps in the
      Theory exist for which there is no evidence.... Intelligent design
      is an explanation of the origin of life that differs from Darwin's
      view. The reference book, Of Pandas and People, is available for
      students to see if they would like to explore this view in an
      effort to gain an understanding of what intelligent design actually
      involves. As is true with any theory, students are encouraged to
      keep an open mind.

    The results were dramatic but predictable. Two school board members
    resigned. All eight science teachers at Dover High School sent a
    letter to the school superintendent pointing out that "intelligent
    design is not science. It is not biology. It is not an accepted
    scientific theory." The biology teachers asked to be excused from
    reading the statement, claiming that to do so would "knowingly and
    intentionally misrepresent subject matter or curriculum," a violation
    of their code of professional standards. And so, in January of this
    year, all ninth-grade biology classes were visited by the assistant
    superintendent himself, who read the mandated disclaimer while the
    teachers and a few students left the room.

    Inevitably, the controversy went to the courts. Eleven Dover parents
    filed suit against the school district and its board of directors,
    asking that the "intelligent design" policy be rescinded for fostering
    "excessive entanglement of government and religion, coerced religious
    instruction, and an endorsement by the state of religion over
    non-religion and of one religious viewpoint over others." The
    plaintiffs are represented by the Philadelphia law firm of Pepper
    Hamilton, the Pennsylvania American Civil Liberties Union, and
    Americans United for Separation of Church and State; the defendants,
    by the Thomas More Law Center, a conservative Christian organization
    in Ann Arbor, Michigan.


    W hy all the fuss about a seemingly inoffensive statement? Who could
    possibly object to students "keep[ing] an open mind" and examining a
    respectable-sounding alternative to evolution? Isn't science about
    testing theories against each other? The furor makes sense only in
    light of the tortuous history of creationism in America. Since it
    arose after World War I, Christianfundamentalist creationism has
    undergone its own evolution, taking on newer forms after absorbing
    repeated blows from the courts. "Intelligent design," as I will show,
    is merely the latest incarnation of the biblical creationism espoused
    by William Jennings Bryan in Dayton. Far from a respectable scientific
    alternative to evolution, it is a clever attempt to sneak religion,
    cloaked in the guise of science, into the public schools.

    The journey from Dayton to Dover was marked by a series of legal
    verdicts, only one of which, the Scopes trial, favored creationism. In
    1925, John Scopes, a high school teacher, was convicted of violating
    Tennessee's Butler Act, which prohibited the teaching of "any theory
    that denies the Story of Divine Creation of Man as taught in the
    Bible, and to teach instead that man has descended from a lower order
    of animal." The verdict was reversed on a technicality (the judge,
    instead of the jury, levied the $100 fine), so the case was never
    appealed. In the wake of Scopes, anti-evolution laws were passed in
    Mississippi and Arkansas, adding to those passed by Florida and
    Oklahoma in 1923. Although these laws were rarely enforced, evolution
    nonetheless quickly disappeared from most high school biology
    textbooks because publishers feared losing sales in the South, where
    anti-evolution sentiment ran high.

    In 1957, the situation changed. With the launch of Sputnik, Americans
    awoke to find that a scientifically advanced Soviet Union had beaten
    the United States into space. This spurred rapid revisions of science
    textbooks, some emphasizing biological evolution. But the
    anti-evolution statutes were still in force, and so some teachers
    using newer books were violating the law. One of these teachers, Susan
    Epperson, brought suit against the state of Arkansas for violating the
    Establishment Clause. She won the right to teach evolution, and
    Epperson v. Arkansas was upheld by the United States Supreme Court in
    1968, only a year after Tennessee finally rescinded the Butler Act.
    Finally it was legal to teach evolution everywhere in America.


    T he opponents of evolution proceeded to re-think their strategy,
    deciding that if they could not beat scientists, they would join them.
    They thus recast themselves as "scientific creationists," proposing an
    ostensibly non-religious alternative to the theory of evolution that
    might be acceptable in the classroom. But the empirical claims of
    scientific creationism--that the Earth is young (6,000 to 10,000 years
    old), that all species were created suddenly and simultaneously, that
    mass extinctions were caused by a great worldwide flood--bore a
    suspicious resemblance to creation stories in the Bible. This strategy
    was devised largely by Henry Morris, an engineering professor who
    headed the influential Institute for Creation Research in San Diego
    and helped to write the textbook Scientific Creationism. The book came
    in two versions: one purged of religious references for the public
    schools, the other containing a scriptural appendix explaining that
    the science came from interpreting the Bible literally.

    Scientific creationism proved a bust for two reasons. First, the
    "science" was ludicrously wrong. We have known for a long time that
    the Earth is 4.6 billion years old (the 6,000- to 10,000-year claim
    comes from biblical statements, including toting up the number of
    "begats") and that species were not created suddenly or simultaneously
    (not only do most species go extinct, but various groups appear at
    different times in the fossil record), and we have ample evidence for
    species' changing over time, as well as for fossils that illustrate
    large morphological transformations. Most risible was Scientific
    Creationism's struggle to explain the geological record as a result of
    a great flood: according to its account, "primitive" organisms such as
    fish would be found in the lowest layers, while mammals and more
    "advanced" species appeared in higher layers because they climbed
    hills and mountains to escape the rising waters. Why dolphins are
    found in the upper strata with other mammals is one of many facts that
    this ludicrous fantasy fails to explain.

    Scientific creationism also came to grief because its advocates did
    not adequately hide its religious underpinnings. In 1981, the Arkansas
    legislature passed an "equal time" bill mandating balanced treatment
    for "evolution science" and "creation science" in the classroom. The
    bill was quickly challenged in federal court by a group of religious
    and scientific plaintiffs led by a Methodist minister named William
    McLean. The defense was easily outgunned, with Judge William Overton
    quickly spotting biblical literalism underlying the
    scientific-creationist arguments. In a landmark opinion (and a
    masterpiece of legal argument), Overton ruled in McLean v. Arkansas
    Board of Education that the balanced-treatment act was
    unconstitutional, asserting that it violated the Establishment Clause
    in three ways: it lacked a secular legislative purpose, its primary
    effect was to advance religion, and it fostered excessive government
    entanglement with religion.

    McLean v. Arkansas Board of Education began a string of legal setbacks
    for scientific creationists. Five years later, in Edwards v.
    Aguillard, the Supreme Court held that Louisiana's "Creationism
    Act"--an act that required the teaching of evolution in public schools
    to be balanced by instruction in "creation science"--was
    unconstitutional. In the last two decades, federal courts have also
    used the First Amendment to allow schools to prohibit teaching
    creationism and to ban school districts from requiring teachers to
    read evolution disclaimers similar to the one used in Dover,
    Pennsylvania. To get around these rulings, schools in Alabama,
    Arkansas, and Georgia began pasting warning stickers in biology
    textbooks, as if learning about evolution could endanger one's mental
    health. A recent specimen from Cobb County, Georgia reads: "This
    textbook contains material on evolution. Evolution is a theory, not a
    fact, regarding the origin of living things. This material should be
    approached with an open mind, studied carefully and critically
    considered."

    To laypeople--particularly those unfamiliar with the scientific status
    of evolution, which is actually a theory and a fact--the phrasing may
    seem harmless. But in 2005 a federal judge ordered the stickers
    removed. By singling out evolution as uniquely controversial among
    scientific theories, the stickers catered to religious biases and thus
    violated the First Amendment.

    But the creationists did not despair. They are animated, after all, by
    faith. And they are very resourceful. They came up with intelligent
    design.


    II.

    I ntelligent design, or ID, is the latest pseudoscientific incarnation
    of religious creationism, cleverly crafted by a new group of
    enthusiasts to circumvent recent legal restrictions. ID comes in two
    parts. The first is a simple critique of evolutionary theory, to the
    effect that Darwinism, as an explanation of the origin, the
    development, and the diversity of life, is fatally flawed. The second
    is the assertion that the major features of life are best understood
    as the result of creation by a supernatural intelligent designer. To
    understand ID, then, we must first understand modern evolutionary
    theory (often called "neo-Darwinism" to take into account
    post-Darwinian modifications).

    It is important to realize at the outset that evolution is not "just a
    theory." It is, again, a theory and a fact. Although non-scientists
    often equate "theory" with "hunch" or "wild guess," the Oxford English
    Dictionary defines a scientific theory as "a scheme or system of ideas
    or statements held as an explanation or account of a group of facts or
    phenomena; a hypothesis that has been confirmed or established by
    observation or experiment, and is propounded or accepted as accounting
    for the known facts." In science, a theory is a convincing explanation
    for a diversity of data from nature. Thus scientists speak of "atomic
    theory" and "gravitational theory" as explanations for the properties
    of matter and the mutual attraction of physical bodies. It makes as
    little sense to doubt the factuality of evolution as to doubt the
    factuality of gravity.

    Neo-Darwinian theory is not one proposition but several. The first
    proposition is that populations of organisms have evolved. (Darwin,
    who used the word "evolved" only once in On the Origin of Species,
    called this principle "descent with modification.") That is, the
    species on earth today are the descendants of other species that lived
    earlier, and the change in these lineages has been gradual, taking
    thousands to millions of years. Humans, for example, evolved from
    distinctly different organisms that had smaller brains and probably
    lived in trees.

    The second proposition is that new forms of life are continually
    generated by the splitting of a single lineage into two or more
    lineages. This is known as "speciation." About five million years ago,
    a species of primates split into two distinct lineages: one leading to
    modern chimpanzees and the other to modern humans. And this ancestral
    primate itself shared a common ancestor with earlier primates, which
    in turn shared a common ancestor with other mammals. The earlier
    ancestor of all mammals shared an even earlier ancestor with reptiles,
    and so on back to the origin of life. Such successive splitting yields
    the common metaphor of an evolutionary "tree of life," whose root was
    the first species to arise and whose twigs are the millions of living
    species. Any two extant species share a common ancestor, which can in
    principle be found by tracing that pair of twigs back through the
    branches to the node where they meet. (Extinction, of course, has
    pruned some branches--pterodactyls, for example--which represent
    groups that died off without descendants.) We are more closely related
    to chimpanzees than to orangutans because our common ancestor with
    these primates lived five million versus ten million years ago,
    respectively. (It is important to note that although we share a common
    ancestor with apes, we did not evolve from living apes, but from
    apelike species that no longer exist. Similarly, I am related to my
    cousin, but the ancestors we share are two extinct grandparents.)

    The third proposition is that most (though not all) of evolutionary
    change is probably driven by natural selection: individuals carrying
    genes that better suit them to the current environment leave more
    offspring than individuals carrying genes that make them less adapted.
    Over time, the genetic composition of a population changes, improving
    its "fit" to the environment. This increasing fit is what gives
    organisms the appearance of design, although, as we shall see, the
    "design" can be flawed.

    These three propositions were first articulated in 1859 by Darwin in
    On the Origin of Species, and they have not changed substantially,
    although they have been refined and supplemented by modern work. But
    Darwin did not propose these ideas as pure "theory"; he also provided
    voluminous and convincing evidence for them. The weight of this
    evidence was so overwhelming that it crushed creationism. Within
    fifteen years, nearly all biologists, previously adherents of "natural
    theology," abandoned that view and accepted Darwin's first two
    propositions. Broad acceptance of natural selection came much later,
    around 1930.

    The overwhelming evidence for evolution can be found in many books
    (and on many websites). Here I wish to present just a few observations
    that not only support the neo-Darwinist account, but in so doing
    refute the alternative theory of creationism--that God specially
    created organisms and their attributes. Given the similarity between
    the claims of intelligent design and creationism, it is not surprising
    that these observations also refute the major tenets of ID.


    T he fossil record is the most obvious place to search for evidence of
    evolution. Although the record was sparse in Darwin's time, there were
    already findings that suggested evolution. The living armadillos of
    South America bore a striking resemblance to fossil glyptodonts,
    extinct armored mammals whose fossils occurred in the same area. This
    suggested that glyptodonts and armadillos shared a common South
    American ancestry. And the record clearly displayed changes in the
    forms of life existing over large spans of time, with the deepest and
    oldest sediments showing marine invertebrates, with fishes appearing
    much later, and still later amphibians, reptiles, and mammals (along
    with the persistence of some groups found in earlier stages). This
    sequence of change was in fact established by creationist geologists
    long before Darwin, and was often thought to reflect hundreds of acts
    of divine creation. (This does not exactly comport with the account
    given in Genesis.)

    Yet evolution predicts not just successions of forms, but also genetic
    lineages from ancestors to descendants. The absence of such
    transitional series in the fossil record bothered Darwin, who called
    this "the most obvious and serious objection that can be urged against
    the theory." (He attributed the missing links, quite reasonably, to
    the imperfection of the fossil record and the dearth of
    paleontological collections.) But this objection is no longer valid.
    Since 1859, paleontologists have turned up Darwin's missing evidence:
    fossils in profusion, with many sequences showing evolutionary change.
    In large and small organisms, we can trace, through successive layers
    of the fossil record, evolutionary changes occurring in lineages.
    Diatoms get bigger, clamshells get ribbier, horses get larger and
    toothier, and the human lineage evolves bigger brains, smaller teeth,
    and increased efficiency at bipedal walking. Moreover, we now have
    transitional forms connecting major groups of organisms, including
    fish with tetrapods, dinosaurs with birds, reptiles with mammals, and
    land mammals with whales. Darwin predicted that such forms would be
    found, and their discovery vindicated him fully. It also destroys the
    creationist notion that species were created in their present form and
    thereafter remained unchanged.


    D arwin's second line of evidence comprised the developmental and
    structural remnants of past ancestry that we find in living
    species--those features that Stephen Jay Gould called "the senseless
    signs of history." Examples are numerous. Both birds and toothless
    anteaters develop tooth buds as embryos, but the teeth are aborted and
    never erupt; the buds are the remnants of the teeth of the reptilian
    ancestor of birds and the toothed ancestor of anteaters. The
    flightless kiwi bird of New Zealand, familiar from shoe-polish cans,
    has tiny vestigial wings hidden under its feathers; they are
    completely useless, but they attest to the fact that kiwis, like all
    flightless birds, evolved from flying ancestors. Some cave animals,
    descended from sighted ancestors that invaded caves, have rudimentary
    eyes that cannot see; the eyes degenerated after they were no longer
    needed. A creator, especially an intelligent one, would not bestow
    useless tooth buds, wings, or eyes on large numbers of species.

    The human body is also a palimpsest of our ancestry. Our appendix is
    the vestigial remnant of an intestinal pouch used to ferment the
    hard-to-digest plant diets of our ancestors. (Orangutans and grazing
    animals have a large hollow appendix instead of the tiny, wormlike one
    that we possess.) An appendix is simply a bad thing to have. It is
    certainly not the product of intelligent design: how many humans died
    of appendicitis before surgery was invented? And consider also lanugo.
    Five months after conception, human fetuses grow a thin coat of hair,
    called lanugo, all over their bodies. It does not seem useful--after
    all, it is a comfortable 98.6 degrees in utero--and the hair is
    usually shed shortly before birth. The feature makes sense only as an
    evolutionary remnant of our primate ancestry; fetal apes also grow
    such a coat, but they do not shed it.

    Recent studies of the human genome provide more evidence that we were
    not created ex nihilo. Our genome is a veritable Gemisch of
    non-functional DNA, including many inactive "pseudogenes" that were
    functional in our ancestors. Why do humans, unlike most mammals,
    require vitamin C in our diet? Because primates cannot synthesize this
    essential nutrient from simpler chemicals. Yet we still carry all the
    genes for synthesizing vitamin C. The gene used for the last step in
    this pathway was inactivated by mutations forty million years ago,
    probably because it was unnecessary in fruit-eating primates. But it
    still sits in our DNA, one of many useless remnants testifying to our
    evolutionary ancestry.


    D arwin's third line of evidence came from biogeography, the study of
    the geographic distribution of plants and animals. I have already
    mentioned what Darwin called his "Law of Succession": living organisms
    in an area most closely resemble fossils found in the same location.
    This implies that the former evolved from the latter. But Darwin found
    his strongest evidence on "oceanic islands"--those islands, such as
    Hawaii and the Galápagos, that were never connected to continents but
    arose, bereft of life, from beneath the sea.

    What struck Darwin about oceanic islands--as opposed to continents or
    "continental islands" such as Great Britain, which were once connected
    to continents--was the bizarre nature of their flora and fauna.
    Oceanic islands are simply missing or impoverished in many types of
    animals. Hawaii has no native mammals, reptiles, or amphibians. These
    animals, as well as freshwater fish, are also missing on St. Helena, a
    remote oceanic island in the middle of the South Atlantic Ocean. It
    seems that the intelligent designer forgot to stock oceanic (but not
    continental!) islands with a sufficient variety of animals. One might
    respond that this was a strategy of the creator, as those organisms
    might not survive on islands. But this objection fails, because such
    animals often do spectacularly well when introduced by humans. Hawaii
    has been overrun by the introduced cane toad and mongoose, to the
    detriment of its native fauna.

    Strikingly, the native groups that are present on these
    islands--mainly plants, insects, and birds--are present in profusion,
    consisting of clusters of numerous similar species. The Galápagos
    archipelago harbors twenty-three species of land birds, of which
    fourteen species are finches. Nowhere else in the world will you find
    an area in which two-thirds of the birds are finches. Hawaii has
    similar "radiations" of fruit flies and silversword plants, while St.
    Helena is overloaded with ferns and weevils. Compared with continents
    or continental islands, then, oceanic islands have unbalanced flora
    and fauna, lacking many familiar groups but having an
    over-representation of some species.

    Moreover, the animals and the plants inhabiting oceanic islands bear
    the greatest similarity to species found on the nearest mainland. As
    Darwin noted when describing the species of the Galápagos, this
    similarity occurs despite a great difference in habitat, a fact
    militating against creationism:

      Why should the species which are supposed to have been created in
      the Galápagos Archipelago, and nowhere else, bear so plainly the
      stamp of affinity to those created in America? There is nothing in
      the conditions of life, in the geological nature of the islands, in
      their height or climate, or in the proportions in which the several
      classes are associated together, which resembles closely the
      conditions of the South American coast: in fact there is a
      considerable dissimilarity in all these respects.

    As the final peg in Darwin's biogeographic argument, he noted that the
    kinds of organisms commonly found on oceanic islands--birds, plants,
    and insects--are those that can easily get there. Insects and birds
    can fly to islands (or be blown there by winds), and the seeds of
    plants can be transported by winds or ocean currents, or in the
    stomachs of birds. Hawaii may have no native terrestrial mammals, but
    the islands do harbor one native aquatic mammal, the monk seal, and
    one native flying mammal, the hoary bat. In a direct challenge to
    creationists (and now also to advocates of ID), Darwin posed this
    rhetorical question:

      Though terrestrial mammals do not occur on oceanic islands, aerial
      mammals do occur on almost every island. New Zealand possesses two
      bats found nowhere else in the world: Norfolk Island, the Viti
      Archipelago, the Bonin Islands, the Caroline and Marianne
      Archipelagoes, and Mauritius, all possess their peculiar bats. Why,
      it may be asked, has the supposed creative force produced bats and
      no other mammals on remote islands?

    The answer is that the creative force did not produce bats, or any
    other creatures, on oceanic islands. All of Darwin's observations
    about island biogeography point to one explanation: species on islands
    descend from individuals who successfully colonized from the mainland
    and subsequently evolved into new species. Only the theory of
    evolution explains the paucity of mammals, birds, reptiles,
    amphibians, and freshwater fish on oceanic islands (they cannot get
    there), the radiation of some groups into many species (the few
    species that make it to islands find empty niches and speciate
    profusely), and the resemblance of island species to those from the
    nearest mainland (an island colonist is most likely to have come from
    the closest source).


    I n the last 150 years, immense amounts of new evidence have been
    collected about biogeography, embryology, and, especially, the fossil
    record. All of it supports evolution. But support for the idea of
    natural selection was not so strong, and Darwin had no direct evidence
    for it. He relied instead on two arguments. The first was logical. If
    individuals in a population varied genetically (which they do), and
    some of this variation affected the individual's chance of leaving
    descendants (which seems likely), then natural selection would work
    automatically, enriching the population in genes that better adapted
    individuals to their environment.

    The second argument was analogical. Artificial selection used by
    breeders had wrought immense changes in plants and animals, a fact
    familiar to everyone. From the ancestral wolf, humans selected forms
    as diverse as Chihuahuas, St. Bernards, poodles, and bulldogs.
    Starting with wild cabbage, breeders produced domestic cabbage,
    broccoli, kohlrabi, kale, cauliflower, and Brussels sprouts.
    Artificial selection is nearly identical to natural selection, except
    that humans rather than the environment determine which variants leave
    offspring. And if artificial selection can produce such a diversity of
    domesticated plants and animals in a thousand-odd years, natural
    selection could obviously do much more over millions of years.

    But we no longer need to buttress natural selection solely with
    analogy and logic. Biologists have now observed hundreds of cases of
    natural selection, beginning with the well-known examples of bacterial
    resistance to antibiotics, insect resistance to DDT, and HIV
    resistance to antiviral drugs. Natural selection accounts for the
    resistance of fish and mice to predators by making them more
    camouflaged, and for the adaptation of plants to toxic minerals in the
    soil. (A long list of examples may be found in Natural Selection in
    the Wild, by John Endler.) Moreover, the strength of selection
    observed in the wild, when extrapolated over long periods, is more
    than adequate to explain the diversification of life on Earth.

    Since 1859, Darwin's theories have been expanded, and we now know that
    some evolutionary change can be caused by forces other than natural
    selection. For example, random and non-adaptive changes in the
    frequencies of different genetic variants--the genetic equivalent of
    coin-tossing--have produced evolutionary changes in DNA sequences. Yet
    selection is still the only known evolutionary force that can produce
    the fit between organism and environment (or between organism and
    organism) that makes nature seem "designed." As the geneticist
    Theodosius Dobzhansky remarked, "Nothing in biology makes sense except
    in the light of evolution."

    And so evolution has graduated from theory to fact. We know that
    species on earth today descended from earlier, different species, and
    that every pair of species had a common ancestor that existed in the
    past. Most evolutionary change in the features of organisms, moreover,
    is almost certainly the result of natural selection. But we must also
    remember that, like all scientific truths, the truth of evolution is
    provisional: it could conceivably be overturned by future
    investigations. It is possible (but unlikely!) that we could find
    human fossils co-existing with dinosaurs, or fossils of birds living
    alongside those of the earliest invertebrates 600 million years ago.
    Either observation would sink neo-Darwinism for good.

    When applied to evolution, the erroneous distinction between theory
    and fact shows why tactics such as the Dover disclaimer and the Cobb
    County textbook sticker are doubly pernicious. To teach that a
    scientific theory is equivalent to a "guess" or a "hunch" is deeply
    misleading, and to assert that "evolution is a theory, not a fact" is
    simply false. And why should evolution, alone among scientific
    theories, be singled out with the caveat "This material should be
    approached with an open mind, studied carefully and critically
    considered"? Why haven't school boards put similar warnings in physics
    textbooks, noting that gravity and electrons are only theories, not
    facts, and should be critically considered? After all, nobody has ever
    seen gravity or an electron. The reason that evolution stands alone is
    clear: other scientific theories do not offend religious
    sensibilities.


    III.

    G iven the copious evidence for evolution, it seems unlikely that it
    will be replaced by an alternative theory. But that is exactly what
    intelligent-design creationists are demanding. Is there some dramatic
    new evidence, then, or some insufficiency of neo-Darwinism, that
    warrants overturning the theory of evolution?

    The question is worth asking, but the answer is no. Intelligent design
    is simply the third attempt of creationists to proselytize our
    children at the expense of good science and clear thinking. Having
    failed to ban evolution from schools, and later to get equal classroom
    time for scientific creationism, they have made a few adjustments
    designed to sneak Christian cosmogony past the First Amendment. And
    these adjustments have given ID a popularity never enjoyed by earlier
    forms of creationism. Even the president of the United States has lent
    a sympathetic ear: George W. Bush recently told reporters in Texas
    that intelligent design should be taught in public schools alongside
    evolution because "part of education is to expose people to different
    schools of thought." Articles by IDers, or about their "theory,"
    regularly appear in mainstream publications such as The New York
    Times.

    Why have the new image and the new approach been more successful? For
    a start, IDers have duped many people by further removing God from the
    picture, or at least hiding him behind the frame. No longer do
    creationists mention a deity, or even a creator, but simply a
    neutral-sounding "intelligent designer," as if it were not the same
    thing. This designer could in principle be Brahma, or the Taoist P'an
    Ku, or even a space alien; but ID creationists, as will be evident to
    anybody who attends to all that they say, mean only one entity: the
    biblical God. Their problem is that invoking this deity in science
    classes in public schools is unconstitutional. So IDers never refer
    openly to God, and people unfamiliar with the history of their
    creationist doctrine might believe that there is a real scientific
    theory afoot. They use imposing new terms such as "irreducible
    complexity," which make their arguments seem more sophisticated than
    those of earlier creationists.

    In addition, many IDers have more impressive academic credentials than
    did earlier scientific creationists, whose talks and antics always
    bore a whiff of the revival meeting. Unlike scientific creationists,
    many IDers work at secular institutions rather than at Bible schools.
    IDers work, speak, and write like trained academics; they do not come
    off as barely repressed evangelists. Their ranks include Phillip
    Johnson, the most prominent spokesperson for ID, and a retired
    professor of law at the University of California, Berkeley; Michael
    Behe, a professor of biochemistry at Lehigh University; William
    Dembski, a mathematician-philosopher and the director of the Center
    for Theology and Science at Southern Baptist Theological Seminary; and
    Jonathan Wells, who has a doctorate in biology from Berkeley.

    All of these proponents, save Johnson, are senior fellows at the
    Center for Science and Culture (CSC), a division of the Discovery
    Institute, which is a conservative think tank in Seattle. (Johnson is
    the "program advisor" to the CSC.) The CSC is the nerve center of the
    intelligentdesign movement. Its origins are demonstrably religious: as
    described by the Discovery Institute, the CSC was designed explicitly
    "to defeat scientific materialism and its destructive moral, cultural,
    and political legacies" and "to replace materialistic explanations
    with the theistic understanding that nature and human beings are
    created by God." Between them, these IDers have published more than a
    dozen books about intelligent design (Johnson alone has produced
    eight), which in turn have provoked numerous responses by scientists.
    Let us examine one of their most influential volumes, the textbook
    called Of Pandas and People. This is the book recommended by the Dover
    school district as a "reference book" for students interested in
    learning about intelligent design.


    O f Pandas and People is a textbook designed as an antidote to the
    evolution segment of high school biology classes. It was first
    published in 1989. By repackaging and updating a subset of traditional
    young-earth creationist arguments while avoiding taking a stand on any
    issues that might divide creationists (such as the age of the Earth),
    it marked the beginning of the modern intelligentdesign movement. By
    presenting the case for ID, it is supposedly designed to give students
    a "balanced perspective" on evolution. Although the second edition of
    Pandas is now twelve years old (a third edition, called Design of
    Life, is in the works), it accurately presents to students the major
    arguments for ID.

    Pandas carefully avoids mentioning God (except under aliases such as
    "intelligent designer," "master intellect," and so on); but a little
    digging reveals the book's deep religious roots. One of its authors,
    Percival Davis, wrote explicitly about his religious beliefs in his
    book A Case for Creation, co-authored with Wayne Frair: "Truth as God
    sees it is revealed in the pages of Scripture, and that revelation is
    therefore more certainly true than any human rationalism. For the
    creationist, revealed truth controls his view of the universe to at
    least as great a degree as anything that has been advanced using the
    scientific method." Its other author, Dean Kenyon, has written
    approvingly of scientific creationism.

    Pandas is published by the Haughton Publishing Company of Dallas, a
    publisher of agricultural books, but the copyright is held by the
    Foundation for Thought and Ethics (FTE) in Richardson, Texas. Although
    the FTE website scrupulously avoids mentioning religion, its articles
    of incorporation note with stark clarity that its "primary purpose is
    both religious and educational, which includes, but is not limited to,
    proclaiming, preaching, teaching, promoting, broadcasting,
    disseminating, and otherwise making known the Christian gospel and
    understanding of the Bible and the light it sheds on the academic and
    social issues of our day." In a fund-raising letter for the proposed
    third edition of Pandas, Jon Buell, president of the FTE, is equally
    frank about his goals:

      We will energetically continue to publish and propel these
      strategic tools in the battle for the minds and hearts of the
      young.... Yes, most young Americans are exposed to numerous gospel
      presentations. But the fog of the alien world view deadens their
      responses. This is why we have to inundate them with a rational,
      defensible, wellargued Judeo-Christian world view. FTE's
      carefully-researched books do just that.

    Charles Thaxton, the "academic editor" of Pandas, is the director of
    curriculum research for FTE and a fellow of the CSC. In a proto-ID
    book on the origin of life, Thaxton argued that "Special Creation by a
    Creator beyond the cosmos is a plausible view of origin science."

    Given Pandas' pedigree and the affiliations of its authors, it is not
    surprising that the book is nothing more than disguised creationism.
    What is surprising is the transparency of this disguise. Despite the
    efforts of IDers to come up with new anti-Darwinian arguments, Pandas
    turns out to be nothing more than recycled scientific creationism,
    with most of the old arguments buffed up and proffered as new. (Unlike
    scientific creationism, however, Pandas adopts a studied neutrality
    toward the facts of astronomy and geology, instead of denying them
    outright.)


    P andas' discussion of the Earth's age is a prime example of the
    book's creationist roots, and of its anti-scientific attitude. If the
    Earth were young--say, the 6,000 to 10,000 years old posited by "young
    earth" biblical creationists--then evolution would be false. Life
    simply could not have originated, evolved, and diversified in such a
    short time. But we now know from several independent and mutually
    corroborating lines of evidence that the Earth is 4.6 billion years
    old. All geologists agree on this. So what is Pandas' stance on this
    critical issue? The book merely notes that design proponents "are
    divided on the issue of the earth's age. Some take the view that the
    earth's history can be compressed into a framework of thousands of
    years, while others adhere to the standard old earth chronology."
    Well, what's the truth? This equivocation is an attempt to paper over
    a strong disagreement between young-earth creationists and old-earth
    creationists, both of whom have marched under the banner of ID. It is
    typical of creationists to exploit disagreements between evolutionists
    as proof that neo-Darwinism is dead while at the same time hiding
    their own disagreements from the public.

    This equivocation about the fundamental fact of Earth's age does not
    bode well for the textbook's treatment of the fossil record. Indeed,
    in this area the authors continue their misrepresentations. Their
    basic premise is the old creationist argument that organisms appeared
    simultaneously and have remained largely unchanged ever since. Pandas
    says of the fossil record that "fully formed organisms appear all at
    once, separated by distinct gaps." That's not exactly true. Different
    types of organisms appear in a distinct sequence supporting evolution.
    The first fossils of living organisms, bacteria, appear 3.5 billion
    years ago, followed two billion years later by algae, the first
    organisms having true cells with a nucleus containing distinct
    chromosomes. Then, 600 million years ago, we see the appearance of
    rudimentary animals with shells, and many soft-bodied marine
    organisms. Later, in the Cambrian period, about 543 million years ago,
    a number of groups arose in a relatively short period of time, the
    so-called "Cambrian explosion." ("Short period" here means
    geologically short, in this case 10 million to 30 million years). The
    Cambrian groups include mollusks, starfish, arthropods, worms, and
    chordates (including vertebrates). And in some cases, such as worms,
    modern groups do not just spring into being, but increase in
    complexity over millions of years.

    Creationists have always made much of the "Cambrian explosion," and
    IDers are no exception. The relatively sudden appearance of many
    groups seems to support the Genesis view of creation. But IDers--and
    Pandas--fail to emphasize several facts. First, the Cambrian explosion
    was not "sudden"; it took many millions of years. (We still do not
    understand why many groups originated in even this relatively short
    time, although it may reflect an artifact: the evolution of easily
    fossilized hard parts suddenly made organisms capable of being
    fossilized.) Moreover, the species of the Cambrian are no longer with
    us, though their descendants are. But over time, nearly every species
    that ever lived (more than 99 percent of them) has gone extinct
    without leaving descendants. Finally, many animals and plants do not
    show up as fossils until well after the Cambrian explosion: bony
    fishes and land plants first appeared around 440 million years ago,
    reptiles around 350 million years ago, mammals around 250 million
    years ago, flowering plants around 210 million years ago, and human
    ancestors around 5 million years ago. The staggered appearance of
    groups that become very different over the next 500 million years
    gives no support to the notion of instantaneously created species that
    thereafter remain largely unchanged. If this record does reflect the
    exertions of an intelligent designer, he was apparently dissatisfied
    with nearly all of his creations, repeatedly destroying them and
    creating a new set of species that just happened to resemble
    descendants of those that he had destroyed.


    P andas also makes much of the supposed absence of transitional forms:
    the "missing" links between major forms of life that, according to
    evolutionary theory, must have existed as common ancestors. Their
    absence, claim creationists, is a major embarrassment for evolutionary
    biology. Phillip Johnson's influential book Darwin on Trial, which
    appeared in 1993, particularly emphasizes these gaps, which, IDers
    believe, reflect the designer's creation of major forms ex nihilo. And
    there are indeed some animals, such as bats, that appear in the fossil
    record suddenly, without obvious ancestors. Yet in most cases these
    gaps are certainly due to the imperfection of the fossil record. (Most
    organisms do not get buried in aquatic sediments, which is a
    prerequisite for fossilization.) And species that are soft-bodied or
    have fragile bones, such as bats, degrade before they can fossilize.
    Paleontologists estimate that we have fossils representing only about
    one in a thousand of all the species that ever lived.

    In its treatment of evolutionary transitions, Pandas is again guilty
    of distortion. Paleontologists have uncovered many transitional forms
    between major groups, almost more than we have a right to expect.
    Pandas simply ignores--or waves away--these "non-missing links,"
    stating that "we cannot form a smooth, unambiguous transitional series
    linking, let's say, the first small horse to today's horse, fishes to
    amphibians, or reptiles to mammals." This is flatly wrong. All three
    cited transitions (and others) are well documented with fossils.
    Moreover, the transitional forms appear at exactly the right time in
    the fossil record: after the ancestral forms already existed, but
    before the "linked" later group had evolved.

    Take one example: the link between early reptiles and later mammals,
    the so-called mammal-like reptiles. Three hundred fifty million years
    ago, the world was full of reptiles, but there were no mammals. By 250
    million years ago, mammals had appeared on the scene. (Fossil reptiles
    are easily distinguished from fossil mammals by a complex of skeletal
    traits including features of the teeth and skull.) Around 275 million
    years ago, forms appear that are intermediate in skeletal traits
    between reptiles and mammals, in some cases so intermediate that the
    animals cannot be unambiguously classified as either reptiles or
    mammals. These mammal-like reptiles, which become less reptilian and
    more mammalian with time, are the no-longer-missing links between the
    two forms, important not only because they have the traits of both
    forms, but also because they occur at exactly the right time.


    O ne of these traits is worth examining in detail because it is among
    the finest examples of an evolutionary transition. This trait is the
    "chewing" hinge where the jaw meets the skull. In early reptiles (and
    their modern reptilian descendants), the lower jaw comprises several
    bones, and the hinge is formed by the quadrate bone of the skull and
    the articular bone of the jaw. As mammal-like reptiles become more
    mammalian, these hinge bones become smaller, and ultimately the jaw
    hinge shifts to a different pair of bones: the dentary (our "jawbone")
    and the squamosal, another bone of the skull. (The quadrate and
    articular, much reduced, moved into the middle ear of mammals, forming
    two of the bones that transmit sounds from the eardrum to the middle
    ear.) The dentary-squamosal articulation occurs in all modern mammals,
    the quadrate-articular in modern reptiles; and this difference is
    often used as the defining feature of these groups.

    Like earlier creationist tracts, Pandas simply denies that this
    evolution of the jaw hinge occurred. It asserts that "there is no
    fossil record of such an amazing process," and further notes that such
    a migration would be "extraordinary." This echoes the old creationist
    argument that an adaptive transition from one type of hinge to another
    by means of natural selection would be impossible: members of a
    species could not eat during the evolutionary period when their jaws
    were being unhinged and then rehinged. (The implication is that the
    intelligent designer must have done this job instantaneously and
    miraculously.) But we have long known how this transition happened. It
    was easily accomplished by natural selection. In 1958, Alfred Crompton
    described the critical fossil: the mammal-like reptile Diarthrognathus
    broomi. D. broomi has, in fact, a double jaw joint with two
    hinges--the reptilian one and the mammalian one! Obviously, this
    animal could chew. What better "missing link" could we find?


    I t should embarrass IDers that so many of the missing links cited by
    Pandas as evidence for supernatural intervention are no longer
    missing. Creationists make a serious mistake when using the absence of
    transitional forms as evidence for an intelligent designer. In the
    last decade, paleontologists have uncovered a fairly complete
    evolutionary series of whales, beginning with fully terrestrial
    animals that became more and more aquatic over time, with their front
    limbs evolving into flippers and their hind limbs and pelvis gradually
    reduced to tiny vestiges. When such fossils are found, as they often
    are, creationists must then punt and change their emphasis to other
    missing links, continually retreating before the advance of science.

    As for other transitional forms, IDers simply dismiss them as aberrant
    fossils. Pandas characterizes Homo erectus and other probable human
    ancestors as "little more than apes." But this is false. While H.
    erectus has a skull with large brow ridges and a braincase much
    smaller than ours, the rest of its skeleton is nearly identical to
    that of modern humans.The famous fossil Archaeopteryx, a small
    dinosaur-like creature with teeth and a basically reptilian skeleton
    but also with wings and feathers, is probably on or closely related to
    the line of dinosaurs that evolved into birds. But Pandas dismisses
    this fossil as just an "odd-ball" type, and laments instead the lack
    of the unfossilizable: "If only we could find a fossil showing scales
    developing the properties of feathers, or lungs that were intermediate
    between the very different reptilian and avian lungs, then we would
    have more to go on." It is again a typical creationist strategy that
    when skeletons of missing links turn up, creationists ignore them and
    insist that evidence of intermediacy be sought instead in the soft
    parts that rarely fossilize. In sum, the treatment of the fossil
    evidence for evolution in Pandas is shoddy and deceptive, and offers
    no advance over the discredited arguments of scientific creationism.


    I n contrast to its long treatment and dismissal of the fossil record,
    Pandas barely deals with evidence for evolution from development and
    vestigial traits. The best it can do is note that vestigial features
    can have a function, and therefore are not really vestigial. The
    vestigial pelvic bones and legs of the transitional whale
    Basilosaurus, which were not connected to the skeleton, may have
    functioned as a guide for the penis during mating. Such a use,
    according to the authors of Pandas, means that the legs and pelvis
    "were not vestigial as originally thought." But this argument is
    wrong: no evolutionist denies that the remnants of ancestral traits
    can retain some functionality or be co-opted for other uses. The
    "penis guide" has every bone in the mammalian pelvis and rear leg in
    reduced form--femur, tibia, fibula, and digits. In Basilosaurus,
    nearly all of these structures lay within the body wall, and most
    parts were immobile. Apparently the intelligent designer had a
    whimsical streak, choosing to construct a sex aid that looked exactly
    like a degenerate pelvis and set of hind limbs.

    And what about the strong evidence for evolution from biogeography?
    About this Pandas, like all creationist books, says nothing. The
    omission is strategic. It would be very hard for IDers to give
    plausible reasons why an "intelligent" designer stocked oceanic
    islands with only a few types of animals and plants--and just those
    types with the ability to disperse from the nearest mainland.
    Biogeography has always been the Achilles' heel of creationists, so
    they just ignore it.


    IV.

    Although intelligent design rejects much of the evidence for
    evolution, it still admits that some evolutionary change occurs
    through natural selection. This change is what Pandas calls
    "microevolution," or "small scale genetic changes, observable in
    organisms." Such microevolutionary changes include the evolution of
    antibiotic resistance in bacteria, changes in the proportion of
    different-colored moths due to predation by birds, and all changes
    wrought by artificial selection. But Pandas hastens to add that
    microevolution gives no evidence for the origin of diverse types of
    organisms, because "these limited changes do not accumulate the way
    Darwinian evolutionary theory requires in order to produce macro
    changes. The process that produces macroevolutionary changes [defined
    here as "large scale changes, leading to new levels of complexity"]
    must be different from any that geneticists have studied so far."

    So, though one can use selection to transform a wolf into either a
    Chihuahua or a St. Bernard, that is merely microevolution: they are
    all still dogs. And a DDT-resistant fly is still a fly. Pandas thus
    echoes the ID assertion that natural selection cannot do more than
    create microevolutionary changes: "It cannot produce new
    characteristics. It only acts on traits that already exist." But this
    is specious reasoning. As we have noted, fossils already show that
    "macro change," as defined by Pandas, has occurred in the fossil
    record (the evolution of fish into amphibians, and so on). And if
    breeders have not turned a dog into another kind of animal, it is
    because dog breeding has been going on for only a few thousand years,
    while the differences between dogs and cats, for example, have evolved
    over more than ten million years. No principle of evolution dictates
    that evolutionary changes observed during a human lifetime cannot be
    extrapolated to much longer periods.

    In fact, Pandas admits that the fruit flies of Hawaii--a diverse group
    of more than 300 species--have all evolved from a common ancestor. We
    now know that this common ancestor lived about 20 million years ago.
    The species of Hawaiian flies differ in many traits, including size,
    shape, ecology, color pattern, mating behavior, and so on. One can in
    fact make a good case that some of the fly species differ more from
    each other than humans differ from chimps. Why, then, do IDers assert
    that chimps and humans (whose ancestor lived only 5 million years ago)
    must have resulted from separate acts of creation by the intelligent
    designer, while admitting that fruit flies evolved from a common
    ancestor that lived 20 million years ago? The answer is that humans
    must at all costs not be lumped in with other species, so as to
    protect the biblical status of humans as uniquely created in God's
    image.


    A ccording to Pandas, the theory of "limits to evolution" is a
    scientific one: "The idea of intelligent design does not preclude the
    possibility that variation within species occurs, or that new species
    are formed from existing populations . . . the theory of intelligent
    design does suggest that there are limits to the amount of variation
    that natural selection and random change mechanisms can produce." But
    there is nothing in the theory of intelligent design that tells us how
    far evolution can go. This "thus far and no further" view of evolution
    comes not from any scientific findings of ID; it comes from ID's
    ancestor, scientific creationism. Scientific Creationism notes that
    "the creation model . . . recognizes only the kind as the basic
    created unit, in this case, mankind," and a chart contrasting
    evolution with the "creation model" says that the former predicts "new
    kinds appearing," while the latter says "no new kinds appearing."

    But what is a "kind"? No creationist has ever defined it, though they
    are all very sure that humans and apes are different "kinds." In fact,
    the notion that evolution and creation have operated together, with
    the latter creating distinct "kinds," was nicely rebutted by Darwin in
    On the Origin of Species:

      Several eminent naturalists . . . admit that they [evolved species]
      have been produced by variation, but they refuse to extend the same
      view to other and very slightly different forms. Nevertheless they
      do not pretend that they can define, or even conjecture, which are
      the created forms of life, and which are those produced by
      secondary laws. They admit variation as a vera causa in one case,
      they arbitrarily reject it in another, without assigning any
      distinction in the two cases. The day will come when this will be
      given as a curious illustration of the blindness of preconceived
      opinion. These authors seem no more startled at a miraculous act of
      creation than at an ordinary birth. But do they really believe that
      at innumerable periods in the earth's history certain elemental
      atoms have been commanded suddenly to flash into living tissues? Do
      they believe that at each supposed act of creation one individual
      or many were produced? Were all the infinitely numerous kinds of
      animals and plants created as egg or seed, or as full grown? and in
      the case of mammals, were they created bearing the false marks of
      nourishment from the mother's womb? Although naturalists very
      properly demand a full explanation of every difficulty from those
      who believe in the mutability of species, on their own side they
      ignore the whole subject of the first appearance of species in what
      they consider reverent silence.

    In fact, the biblical appendix of Scientific Creationism shows that
    the term "kind" derives from the biblical notion of created kinds:

      The Scriptures are very clear in their teaching that God created
      all things as He wanted them to be, each with its own particular
      structure, according to His own sovereign purposes. The account of
      Genesis 1, for example, indicates that at least ten major
      categories of organic life were specially created "after his kind."
      . . . Finally, man "kind" was created as another completely
      separate category. The phrase "after his kind" occurs ten times in
      this first chapter of Genesis.

    There is thus a clear line of descent from the story of Genesis to the
    ID notion of evolutionary limits, a line charted by what Darwin called
    "the blindness of preconceived opinion." Until IDers tell us what the
    limits to evolution are, how they can be ascertained, and what
    evidence supports these limits, this notion cannot be regarded as a
    genuinely scientific claim.


    V.

    I Ders make one claim that they tout as truly novel, a claim that has
    become quite popular. It is the idea that organisms show some
    adaptations that could not be built by natural selection, thus
    implying the need for a supernatural creative force such as an
    intelligent designer. These adaptations share a property called
    "irreducible complexity," a characteristic discussed in Pandas but
    defined more explicitly by Michael Behe in 1996 in his book Darwin's
    Black Box: The Biochemical Challenge to Evolution: "By irreducibly
    complex I mean a single system composed of several well-matched,
    interacting parts that contribute to the basic function, wherein the
    removal of any one of the parts causes the system to effectively cease
    functioning."

    Many man-made objects show this property: Behe cites the mousetrap,
    which would not work if even one part were removed, such as the catch,
    the spring, the base, and so on. Pandas mentions a car engine, which
    will not work if one removes the fan belt, spark plugs, distributor
    cap, or any of numerous individual parts. A famous example of an
    irreducibly complex system in the biological realm is the "camera" eye
    of humans and other vertebrates. The eye has many parts whose
    individual removal would render the organ useless, including the lens,
    retina, and optic nerve.

    The reason IDers love "irreducibly complex" features of organisms is
    that natural selection is powerless (or so they claim) to create such
    features. As Behe notes:

      An irreducibly complex system cannot be produced directly ... by
      slight, successive modifications of a precursor system, because any
      precursor to an irreducibly complex system that is missing a part
      is by definition nonfunctional.... Since natural selection can only
      choose systems that are already working, then if a biological
      system cannot be produced gradually it would have to arise as an
      integrated unit, in one fell swoop, for natural selection to have
      anything to act on.

    "One fell swoop," of course, implies that the feature must have been
    produced by the miraculous intervention of the intelligent designer.

    But this argument for intelligent design has a fatal flaw. We have
    realized for decades that natural selection can indeed produce systems
    that, over time, become integrated to the point where they appear to
    be irreducibly complex. But these features do not evolve by the
    sequential addition of parts to a feature that becomes functional only
    at the end. They evolve by adding, via natural selection, more and
    more parts into an originally rudimentary but functional system, with
    these parts sometimes co-opted from other structures. Every step of
    this process improves the organism's survival, and so is
    evolutionarily possible via natural selection.


    C onsider the eye. Creationists have long maintained that it could not
    have resulted from natural selection, citing a sentence from On the
    Origin of Species: "To suppose that the eye with all its inimitable
    contrivances for adjusting the focus to different distances, for
    admitting different amounts of light, and for the correction of
    spherical and chromatic aberration, could have been formed by natural
    selection, seems, I freely confess, absurd in the highest degree." But
    in the next passage, invariably omitted by creationists, Darwin
    ingeniously answers his own objection:

      Reason tells me, that if numerous gradations from a simple and
      imperfect eye to one complex and perfect can be shown to exist,
      each grade being useful to its possessor, as is certainly the case;
      if further, the eye ever varies and the variations be inherited, as
      is likewise certainly the case and if such variations should be
      useful to any animal under changing conditions of life, then the
      difficulty of believing that a perfect and complex eye could be
      formed by natural selection, though insuperable by our imagination,
      should not be considered as subversive of the theory.

    Thus our eyes did not suddenly appear as full-fledged camera eyes, but
    evolved from simpler eyes, having fewer components, in ancestral
    species. Darwin brilliantly addressed this argument by surveying
    existing species to see if one could find functional but less complex
    eyes that not only were useful, but also could be strung together into
    a hypothetical sequence showing how a camera eye might evolve. If this
    could be done--and it can--then the argument for irreducible
    complexity vanishes, for the eyes of existing species are obviously
    useful, and each step in the hypothetical sequence could thus evolve
    by natural selection.

    A possible sequence of such changes begins with pigmented eye spots
    (as seen in flatworms), followed by an invagination of the skin to
    form a cup protecting the eyespot and allowing it to better localize
    the image (as in limpets), followed by a further narrowing of the
    cup's opening to produce an improved image (the nautilus), followed by
    the evolution of a protective transparent cover to protect the opening
    (ragworms), followed by coagulation of part of the fluid in the
    eyeball into a lens to help focus the light (abalones), followed by
    the co-opting of nearby muscles to move the lens and vary the focus
    (mammals). The evolution of a retina, an optic nerve, and so on would
    follow by natural selection. Each step of this transitional "series"
    confers increased adaptation on its possessor, because it enables the
    animal to gather more light or to form better images, both of which
    aid survival. And each step of this process is exemplified by the eye
    of a different living species. At the end of the sequence we have the
    camera eye, which seems irreducibly complex. But the complexity is
    reducible to a series of small, adaptive steps.


    N ow, we do not know the precise order in which the components of the
    camera eye evolved--but the point is that the appearance of
    "irreducible complexity" cannot be an argument against neo-Darwinism
    if we can document a plausible sequence in which the complexity can
    arise from a series of adaptive steps. The "irreducible complexity"
    argument is not, in fact, completely novel. It descends, with
    modification, from the British theologian William Paley, who in 1802
    raised the famous "argument from design" in his book Natural Theology.
    Paley argued that just as finding a watch on the ground implies a
    conscious designer (the watchmaker), so finding an equally complex
    organism implies a cosmic designer (God).

    But the eye is not a watch. The human eye, though eminently
    functional, is imperfect--certainly not the sort of eye an engineer
    would create from scratch. Its imperfection arises precisely because
    our eye evolved using whatever components were at hand, or produced by
    mutation. Since our retina evolved from an everted part of the brain,
    for example, the nerves and blood vessels that attach to our
    photoreceptor cells are on the inside rather than the outside of the
    eye, running over the surface of the retina. Leakage of these blood
    vessels can occlude vision, a problem that would not occur if the
    vessels fed the retina from behind. Likewise, to get the nerve
    impulses from the photocells to the brain, the different nerves must
    join together and dive back through the eye, forming the optic nerve.
    This hole in the retina creates a blind spot in the eye, a flaw that
    again would be avoidable with a priori design. The whole system is
    like a car in which all the wires to the dashboard hang inside the
    driver's compartment instead of being tucked safely out of sight.
    Evolution differs from a priori design because it is constrained to
    operate by modifying whatever features have evolved previously. Thus
    evolution yields fitter types that often have flaws. These flaws
    violate reasonable principles of intelligent design.

    IDers tend to concentrate more on biochemistry than on organs such as
    the eye, citing "irreducibly complex" molecular systems such as the
    mechanism for blood-clotting and the immune system. Like the eye,
    these systems supposedly could not have evolved, since removal of any
    step in these pathways would render the entire pathway non-functional.
    (This biochemical complexity is the subject of Behe's book Darwin's
    Black Box.) Discussing the blood-clotting system in its sixth chapter
    (partially written by Behe), Pandas asserts that "like a car engine,
    biological systems can only work after they have been assembled by
    someone who knows what the final result will be." This is nonsense. As
    we have seen in the case of the eye, biological systems are not useful
    only at the end of a long evolutionary process, but during every step
    of that process. And biochemical systems--like all adaptations created
    by natural selection--are not assembled with foresight. Whatever
    useful mutations happen to arise get folded into the system.

    There is no doubt that many biochemical systems are dauntingly
    complex. A diagram of the blood-clotting pathway looks like a
    complicated circuit board, with dozens of proteins interacting with
    one another to one end: healing a wound. And the system seems
    irreducibly complex, because without any of several key proteins, the
    blood would not clot. Yet such biochemical systems evolved in the same
    way that the eye evolved, by adding parts successively and adaptively
    to simpler, functioning systems. It is more difficult to trace the
    evolution of biochemical pathways than of anatomical structures
    because the ancestral metabolic pathways are no longer present. But
    biologists are beginning to provide plausible scenarios for how
    "irreducibly complex" biochemical pathways might have evolved. As
    expected, these systems involve using bits co-opted from other
    pathways originally having different functions. (Thus, one of the
    enzymes in the blood-clotting system also plays a role in digestion
    and cell division.) In view of our progress in understanding
    biochemical evolution, it is simply irrational to say that because we
    do not completely understand how biochemical pathways evolved, we
    should give up trying and invoke the intelligent designer. If the
    history of science shows us anything, it is that we get nowhere by
    labeling our ignorance "God."


    VI.

    Insofar as intelligent-design theory can be tested scientifically, it
    has been falsified. Organisms simply do not look as if they had been
    intelligently designed. Would an intelligent designer create millions
    of species and then make them go extinct, only to replace them with
    other species, repeating this process over and over again? Would an
    intelligent designer produce animals having a mixture of mammalian and
    reptilian traits, at exactly the time when reptiles are thought to
    have been evolving into mammals? Why did the designer give tiny,
    non-functional wings to kiwi birds? Or useless eyes to cave animals?
    Or a transitory coat of hair to a human fetus? Or an appendix, an
    injurious organ that just happens to resemble a vestigial version of a
    digestive pouch in related organisms? Why would the designer give us a
    pathway for making vitamin C, but then destroy it by disabling one of
    its enzymes? Why didn't the intelligent designer stock oceanic islands
    with reptiles, mammals, amphibians, and freshwater fish, despite the
    suitability of such islands for these species? And why would he make
    the flora and fauna on those islands resemble that of the nearest
    mainland, even when the environments are very different? Why, about a
    million years ago, would the designer produce creatures that have an
    apelike cranium perched atop a humanlike skeleton? And why would he
    then successively replace these creatures with others having an
    ever-closer resemblance to modern humans?

    There are only two answers to these questions: either life resulted
    not from intelligent design, but from evolution; or the intelligent
    designer is a cosmic prankster who designed everything to make it look
    as though it had evolved. Few people, religious or otherwise, will
    find the second alternative palatable. It is the modern version of the
    old argument that God put fossils in the rocks to test our faith.

    The final blow to the claim that intelligent design is scientific is
    its proponents' admission that we cannot understand the designer's
    goals or methods. Behe owns up to this in Darwin's Black Box:
    "Features that strike us as odd in a design might have been placed
    there by the designer for a reason--for artistic reasons, to show off,
    for some as-yetundetectable practical purpose, or for some unguessable
    reason--or they might not." And, discussing skeletal differences
    between placental and marsupial mammals, Pandas notes:

      Why were not the North American placentals given the same bones?
      Would an intelligent designer withhold these structures from
      placentals if they were superior to the placental system? At
      present we do not know; however, we all recognize that an engineer
      can choose any of several different engineering solutions to
      overcome a single design problem. An intelligent designer might
      reasonably be expected to use a variety (if a limited variety) of
      design approaches to produce a single engineering solution, also.
      Even if it is assumed that an intelligent designer did indeed have
      a good reason for every decision that was made, and for including
      every trait in each organism, it does not follow that such reasons
      will be obvious to us.

    Well, if we admit that the designer had a number of means and motives,
    which can be self-contradictory, arbitrary, improvisatory, and
    "unguessable," then we are left with a theory that cannot be rejected.
    Every conceivable observation of nature, including those that support
    evolution, becomes compatible with ID, for the ways of the designer
    are unfathomable. And a theory that cannot be rejected is not a
    scientific theory. If IDers want to have a genuinely scientific
    theory, let them propose a model that can be rigorously tested.


    G iven its lack of rigor, one might expect that ID theory would not
    inspire much scientific research. And there is virtually none. Despite
    the claims of ID to be a program of research, its adherents have
    published only one refereed paper supporting ID in a scientific
    journal: a review of ID by Stephen C. Meyer, the director of the
    Discovery Institute's Center for Science and Culture, which appeared
    in the Proceedings of the Biological Society of Washington. This paper
    merely rehashes ID arguments for why natural selection and evolution
    cannot explain the diversity of life and then asserts that intelligent
    design is the only alternative. It distorts the evolutionary
    literature it purports to review, and it neither advances new
    scientific arguments nor suggests any way that ID better explains
    patterns in nature. Not surprisingly, the Council of the Biological
    Society of Washington later disowned the paper because it did "not
    meet the scientific standards of the Proceedings."

    The gold standard for modern scientific achievement is the publication
    of new results in a peer-reviewed scientific journal. By that
    standard, IDers have failed miserably. As William Dembski himself
    noted, "There are good and bad reasons to be skeptical of intelligent
    design. Perhaps the best reason is that intelligent design has yet to
    establish itself as a thriving scientific research program." IDers
    desperately crave scientific respectability, but it is their own
    theory that prevents them from attaining it. Thus, while IDers demand
    that evolutionists produce thousands of transitional fossils and
    hundreds of detailed scenarios about the evolution of biochemical
    pathways, they put forth no observations supporting the plausibility
    of a supernatural designer, nor do they show how appeal to such a
    designer could explain the fossil record, embryology, and biogeography
    better than neo-Darwinism. Herbert Spencer could have been describing
    ID when he declared that "those who cavalierly reject the Theory of
    Evolution as not being adequately supported by facts, seem to forget
    that their own theory is supported by no facts at all. Like the
    majority of men who are born to a given belief, they demand the most
    rigorous proof of any adverse belief, but assume that their own needs
    none."

    Finally, the reliance of ID on supernatural intervention means that
    the enterprise cannot be seen, strictly speaking, as scientific. In
    his rejection of scientific creationism in McLean v. Arkansas, Judge
    Overton described the characteristics of good science:

      (1) It is guided by natural law;
      (2) It has to be explanatory by reference to natural law;
      (3) It is testable against the empirical world;
      (4) Its conclusions are tentative, i.e., are not necessarily the
      final word; and
      (5) It is falsifiable.

    By invoking the repeated occurrence of supernatural intervention by an
    intelligent designer to create new species and new traits, ID violates
    criteria 1 and 2; and in its ultimate reliance on Christian dogma and
    God, it violates criteria 3, 4, and 5.

    In candid moments, usually when writing for or speaking to a religious
    audience, IDers admit the existence not only of supernatural acts as a
    part of their theory, but also of Christian supernatural acts. In a
    foreword to a book on creationism, Johnson wrote: "The intelligent
    design movement starts with the recognition that 'In the beginning was
    the Word,' and 'In the beginning God created.' Establishing that point
    isn't enough, but it is absolutely essential to the rest of the gospel
    message." And here is Dembski writing in Touchstone, a Christian
    magazine: "The world is a mirror representing the divine life....
    Intelligent design readily embraces the sacramental nature of physical
    reality. Indeed intelligent design is just the Logos theology of
    John's Gospel restated in the idiom of information theory." Indeed, in
    the manuscript draft of the first edition of Pandas, the terms
    "creationism," "creationist," and "creation" are used repeatedly
    instead of the equivalent ID terms, and "creationism" is defined
    identically to "intelligent design" in the published version. Nothing
    gives a clearer indication that one ancestor of this textbook was the
    Bible.


    I t is clear, then, that intelligent design did not arise because of
    some long-standing problems with evolutionary theory, or because new
    facts have called neoDarwinism into question. ID is here for only one
    reason--to act as a Trojan horse poised before the public schools: a
    seemingly secular vessel ready to inject its religious message into
    the science curriculum. The contents of Pandas, and of the other
    writings of IDers, are simply a cunning pedagogical ploy to circumvent
    legal restrictions against religious creationism. (With any luck,
    though, the publicity will backfire. Last month The York Dispatch in
    Pennsylvania reported that the Foundation for Thought and Ethics, the
    group that publishes this textbook and others designed to present "a
    Christian perspective," wanted to intervene in the Dover lawsuit.
    According to John Buell, the foundation's president, the association
    of ID with creationism "would make the book radioactive," and his
    outfit could lose as much as $525,000 in sales.)

    ID is part of what Johnson candidly calls the "wedge strategy," a
    carefully crafted scheme that begins with the adoption of intelligent
    design as an alternative theory to evolution, after which ID will edge
    out evolution until it is the only view left, after which it will
    become full-blown biblical creationism. The ultimate goal is to
    replace naturalist science with spiritualist thinking, and the method
    is to hammer the wedge of ID into science at its most vulnerable
    point: public education. In Johnson's own words:

      So the question is: "How to win?" That's when I began to develop
      what you now see full-fledged in the "wedge" strategy: "stick with
      the most important thing," the mechanism and the building up of
      information. Get the Bible and the Book of Genesis out of the
      debate because you do not want to raise the so-called Bible-science
      dichotomy. Phrase the argument in such a way that you can get it
      heard in the secular academy and in a way that tends to unify the
      religious dissenters. That means concentrating on, "Do you need a
      Creator to do the creating, or can nature do it on its own?" and
      refusing to get sidetracked onto other issues, which people are
      always trying to do.


    Johnson was even more explicit in 1999 in remarks to a conference on
    "Reclaiming America for Christ." Rob Boston reported Johnson's remarks
    in Church & State magazine:

      Johnson calls his movement "The Wedge." The objective, he said, is
      to convince people that Darwinism is inherently atheistic, thus
      shifting the debate from creationism v. evolution to the existence
      of God v. the nonexistence of God. From there people are introduced
      to "the truth" of the Bible and then "the question of sin" and
      finally "introduced to Jesus."

    Other major figures in the ID movement have been equally clear about
    their religious motivations. Here is Dembski:

      But there are deeper motivations. I think at a fundamental level,
      in terms of what drives me in this is that I think God's glory is
      being robbed by these naturalistic approaches to biological
      evolution, creation, the origin of the world, the origin of
      biological complexity and diversity. When you are attributing the
      wonders of nature to these mindless material mechanisms, God's
      glory is getting robbed.

    And here is Jonathan Wells, a member of Reverend Moon's Unification
    Church:

      Father's [Reverend Moon's] words, my studies, and my prayers
      convinced me that I should devote my life to destroying Darwinism,
      just as many of my fellow Unificationists had already devoted their
      lives to destroying Marxism. When Father chose me (along with about
      a dozen other seminary graduates) to enter a Ph.D. program in 1978,
      I welcomed the opportunity to prepare myself for battle.


    D o these people really believe in intelligent design? There is no
    reason to think otherwise. They are not lying for their cause, but
    sincerely hold that life on earth reflects a succession of miracles
    worked by a supernatural agent. In fact, they view evolutionists as
    the duplicitous ones. In an interview in The Sacramento Bee in 1991,
    Johnson proclaimed that "scientists have long known that Darwinism is
    false. They have adhered to the myth out of self-interest and a
    zealous desire to put down God." Never mind that many scientists,
    including evolutionists, are religious.

    Given the overwhelming evidence for evolution and the lack of evidence
    for ID, how can intelligent people hold such views? Is their faith so
    strong that it blinds them to all evidence? It is a bit more
    complicated than that. After all, many theologians and religious
    people accept evolution. The real issues behind intelligent
    design--and much of creationism--are purpose and morality:
    specifically, the fear that if evolution is true, then we are no
    different from other animals, not the special objects of God's
    creation but a contingent product of natural selection, and so we lack
    real purpose, and our morality is just the law of the jungle. Tom
    DeLay furnished a colorful example of this view on the floor of the
    House of Representatives on June 16, 1999. Explaining the causes of
    the massacre at Columbine High School, he read a sarcastic letter in a
    Texas newspaper that suggested that "it couldn't have been because our
    school systems teach the children that they are nothing but glorified
    apes who have evolutionized out of some primordial soup of mud."

    The notion that naturalism and materialism are the enemies of morality
    and a sense of human purpose, and that religion is their only ally, is
    pervasive in the writings of IDers. As Johnson noted, "Once God is
    culturally determined to be imaginary, then God's morality loses its
    foundation and withers away." Nancy Pearcey, a senior fellow of the
    Discovery Institute's Center for Science and Culture, summarizes why
    evolution disturbs so many Americans:

      Why does the public care so passionately about a theory of biology?
      Because people sense intuitively that there's much more at stake
      than a scientific theory. They know that when naturalistic
      evolution is taught in the science classroom, then a naturalistic
      view of ethics will be taught down the hallway in the history
      classroom, the sociology classroom, the family life classroom, and
      in all areas of the curriculum.

    Even some parents in Dover, though opposed to teaching ID in school,
    worry that learning evolution will erode the Christian values that
    they are trying to instill in their children.

    But the acceptance of evolution need not efface morality or purpose.
    Evolution is simply a theory about the process and patterns of life's
    diversification, not a grand philosophical scheme about the meaning of
    life. Philosophers have argued for years about whether ethics should
    have a basis in nature. There is certainly no logical connection
    between evolution and immorality. Nor is there a causal connection: in
    Europe, religion is far less pervasive than in America, and belief in
    evolution is more widespread, but somehow the continent remains
    civilized. Most religious scientists, laymen, and theologians have not
    found the acceptance of evolution to impede living an upright,
    meaningful life. And the idea that religion provides the sole
    foundation for meaning and morality also cannot be right: the world is
    full of skeptics, agnostics, and atheists who live good and meaningful
    lives.


    B arring a miracle, the Dover Area School District will lose its case.
    Anyone who bothers to study ID and its evolution from earlier and more
    overtly religious forms of creationism will find it an unscientific,
    faith-based theory ultimately resting on the doctrines of
    fundamentalist Christianity. Its presentation in schools thus violates
    both the Constitution and the principles of good education. There is
    no secular reason why evolutionary biology, among all the sciences,
    should be singled out for a school-mandated disclaimer. But the real
    losers will be the people of Dover, who will likely be saddled with
    huge legal bills and either a substantial cut in the school budget or
    a substantial hike in property taxes. We can also expect that, if they
    lose, the IDers will re-group and return in a new disguise even less
    obviously religious. I await the formation of the Right to Teach
    Problems with Evolution Movement.

    IDers have been helped by Americans' continuing doubts about the truth
    of evolution. According to a Gallup poll taken last year, 45 percent
    of Americans agree with the statement, "God created human beings
    pretty much in their present form at one time within the last 10,000
    years." Asked if evolution is well supported by evidence, 35 percent
    of Americans said yes, 35 percent said no, and 29 percent said they
    lack the knowledge to reply. As a rationalist, I cannot help but
    believe that the first group would swell were Americans to be
    thoroughly taught the evidence for evolution, which is rarely done in
    public high schools. I have seen creationist students become
    evolutionists when they learn about biogeography or examine the skulls
    of mammal-like reptiles. What we need in the schools is not less
    teaching of evolution but more.

    In the end, many Americans may still reject evolution, finding the
    creationist alternative psychologically more comfortable. But emotion
    should be distinguished from thought, and a "comfort level" should not
    affect what is taught in the science classroom. As Judge Overton wrote
    in his magisterial decision striking down Arkansas Act 590, which
    mandated equal classroom time for "scientific creationism":

      The application and content of First Amendment principles are not
      determined by public opinion polls or by a majority vote. Whether
      the proponents of Act 590 constitute the majority or the minority
      is quite irrelevant under a constitutional system of government. No
      group, no matter how large or small, may use the organs of
      government, of which the public schools are the most conspicuous
      and influential, to foist its religious beliefs on others.

    [3]Jerry Coyne is a professor in the Department of Ecology and
    Evolution at the University of Chicago.

    RELATED LINKS
    [4]Creations
    Intelligent design is an expression of sentiment, not an exercise of
    reason.  [5]Majority Rules
    What the religious right and radical multiculturalists have in
    common.  [tnrd_blurb_logo.gif]  web only
    [6]Evolutionary War
    Do leading conservative pundits and thinkers believe in evolution? We
    asked them. web only

References

    4. http://www.tnr.com/doc.mhtml?i=20050822&s=diarist082205
    5. http://www.tnr.com/doc.mhtml?i=w050808&s=reifowitz081005
    6. http://www.tnr.com/doc.mhtml?i=w050704&s=adler070705