You could give Aristotle a tutorial. And you could thrill him to the core of his being. Aristotle was an encyclopedic polymath, an all time intellect. Yet not only can you know more than him about the world. You also can have a deeper understanding of how everything works. Such is the privilege of living after Newton, Darwin, Einstein, Planck, Watson, Crick and their colleagues.
I'm not saying you're more intelligent than Aristotle, or wiser. For all I know, Aristotle's the cleverest person who ever lived. That's not the point. The point is only that science is cumulative, and we live later.
Aristotle had a lot to say about astronomy, biology and physics. But his views sound weirdly naive today. Not as soon as we move away from science, however. Aristotle could walk straight into a modern seminar on ethics, theology, political or moral philosophy, and contribute. But let him walk into a modern science class and he'd be a lost soul. Not because of the jargon, but because science advances, cumulatively.
Here's a small sample of the things you could tell Aristotle, or any other Greek philosopher. And surprise and enthrall them, not just with the facts themselves but with how they hang together so elegantly.
The earth is not the center of the universe. It orbits the sun — which is just another star. There is no music of the spheres, but the chemical elements, from which all matter is made, arrange themselves cyclically, in something like octaves. There are not four elements but about 100. Earth, air, fire and water are not among them.
Living species are not isolated types with unchanging essences. Instead, over a time scale too long for humans to imagine, they split and diverge into new species, which then go on diverging further and further. For the first half of geological time our ancestors were bacteria. Most creatures still are bacteria, and each one of our trillions of cells is a colony of bacteria. Aristotle was a distant cousin to a squid, a closer cousin to a monkey, a closer cousin still to an ape (strictly speaking, Aristotle was an ape, an African ape, a closer cousin to a chimpanzee than a chimp is to an orangutan).
The brain is not for cooling the blood. It's what you use to do your logic and your metaphysics. It's a three dimensional maze of a million million nerve cells, each one drawn out like a wire to carry pulsed messages. If you laid all your brain cells end to end, they'd stretch round the world 25 times. There are about 4 million million connections in the tiny brain of a chaffinch, proportionately more in ours.
Now, if you're anything like me, you'll have mixed feelings about that recitation. On the one hand, pride in what Aristotle's species now knows and didn't then. On the other hand an uneasy feeling of, "Isn't it all a bit complacent? What about our descendants, what will they be able to tell us?"
Yes, for sure, the process of accumulation doesn't stop with us. 2000 years hence, ordinary people who have read a couple of books will be in a position to give a tutorial to today's Aristotles: to Francis Crick, say, or Stephen Hawking. So does this mean that our view of the universe will turn out to be just as wrong?
Let's keep a sense of proportion about this! Yes, there's much that we still don't know. But surely our belief that the earth is round and not flat, and that it orbits the sun, will never be superseded. That alone is enough to confound those, endowed with a little philosophical learning, who deny the very possibility of objective truth: those so-called relativists who see no reason to prefer scientific views over aboriginal myths about the world.
Our belief that we share ancestors with chimpanzees, and more distant ancestors with monkeys, will never be superseded although details of timing may change. Many of our ideas, on the other hand, are still best seen as theories or models whose predictions, so far, have survived the test. Physicists disagree over whether they are condemned forever to dig for deeper mysteries, or whether physics itself will come to an end in a final 'theory of everything', a nirvana of knowledge. Meanwhile, there is so much that we don't yet understand, we should loudly proclaim those things that we do, so as to focus attention on problems that we should be working on.
Far from being over-confident, many scientists believe that science advances only by disproof of its hypotheses. Konrad Lorenz said he hoped to disprove at least one of his own hypotheses every day before breakfast. That was absurd, especially coming from the grand old man of the science of ethology, but it is true that scientists, more than others, impress their peers by admitting their mistakes.
A formative influence on my undergraduate self was the response of a respected elder statesmen of the Oxford Zoology Department when an American visitor had just publicly disproved his favorite theory. The old man strode to the front of the lecture hall, shook the American warmly by the hand and declared in ringing, emotional tones: "My dear fellow, I wish to thank you. I have been wrong these fifteen years." And we clapped our hands red. Can you imagine a Government Minister being cheered in the House of Commons for a similar admission? "Resign, Resign" is a much more likely response!
Yet there is hostility towards science. And not just from the green ink underlining brigade, but from published novelists and newspaper columnists. Newspaper columns are notoriously ephemeral, but their drip drip, week after week, or day after day, repetition gives them influence and power, and we have to notice them. A peculiar feature of the British press is the regularity with which some of its leading columnists return to attack science — and not always from a vantage point of knowledge. A few weeks ago, Bernard Levin's effusion in The Times was entitled "God, me and Dr. Dawkins" and it had the subtitle: "Scientists don't know and nor do I — but at least I know I don't know".
It is no mean task to plumb the full depths of what Mr. Bernard Levin does not know, but here's an illustration of the gusto with which he boasts of it.
Despite their access to copious research funds, today's scientists have yet to prove that a quark is worth a bag of beans. The quarks are coming! The quarks are coming! Run for your lives . . .! Yes, I know I shouldn't jeer at science, noble science, which, after all, gave us mobile telephones, collapsible umbrellas and multi-striped toothpaste, but science really does ask for it . . . Now I must be serious. Can you eat quarks? Can you spread them on your bed when the cold weather comes?
It doesn't deserve a reply, but the distinguished Cambridge scientist, Sir Alan Cottrell, wrote a brief Letter to the Editor:— "Sir: Mr. Bernard Levin asks 'Can you eat quarks?' I estimate that he eats 500,000,000,000,000,000,000 quarks a day."
It has become almost a cliché to remark that nobody boasts of ignorance of literature, but it is socially acceptable to boast ignorance of science and proudly claim incompetence in mathematics. In Britain, that is. I believe the same is not true of our more successful economic competitors, Germany, the United States and Japan.
People certainly blame science for nuclear weapons and similar horrors. It's been said before but needs to be said again: if you want to do evil, science provides the most powerful weapons to do evil; but equally, if you want to do good, science puts into your hands the most powerful tools to do so. The trick is to want the right things, then science will provide you with the most effective methods of achieving them.
An equally common accusation is that science goes beyond its remit. It's accused of a grasping take-over bid for territory that properly belongs to other disciplines such as theology. On the other hand — you can't win! — listen to the novelist Fay Weldon's hymn of hate against 'the scientists' in The Daily Telegraph.
Don't expect us to like you. You promised us too much and failed to deliver. You never even tried to answer the questions we all asked when we were six. Where did Aunt Maud go when she died? Where was she before she was born? . . . And who cares about half a second after the Big Bang; what about half a second before? And what about crop circles?
More than some of my colleagues, I am perfectly happy to give a simple and direct answer to both those Aunt Maud questions. But I'd certainly be called arrogant and presumptuous, going beyond the limits of science.
Then there's the view that science is dull and plodding, with rows of pens in its top pocket. Here's another newspaper columnist, A A Gill, writing on science this year in The Sunday Times.
Science is constrained by experiment results and the tedious, plodding stepping stones of empiricism . . . What appears on television just is more exciting than what goes on in the back of it . . . That's art, luvvie: theater, magic, fairy dust, imagination, lights, music, applause, my public. There are stars and there are stars, darling. Some are dull, repetitive squiggles on paper, and some are fabulous, witty, thought-provoking, incredibly popular...."
The 'dull, repetitive squiggles' is a reference to the discovery of pulsars in 1967, by Jocelyn Bell and Anthony Hewish. Jocelyn Bell Burnell had recounted on television the spine-tingling moment when, a young woman on the threshold of a career, she first knew she was in the presence of something hitherto unheard-of in the universe. Not something new under the sun, a whole new kind of sun, which rotates, so fast that, instead of taking 24 hours like our planet, it takes a quarter of a second. Darling, how too plodding, how madly empirical my dear!
Could science just be too difficult for some people, and therefore seem threatening? Oddly enough, I wouldn't dare to make such a suggestion, but I am happy to quote a distinguished literary scholar, John Carey, the present Merton Professor of English at Oxford:
The annual hordes competing for places on arts courses in British universities, and the trickle of science applicants, testify to the abandonment of science among the young. Though most academics are wary of saying it straight out, the general consensus seems to be that arts courses are popular because they are easier, and that most arts students would simply not be up to the intellectual demands of a science course.
My own view is that the sciences can be intellectually demanding, but so can classics, so can history, so can philosophy. On the other hand, nobody should have trouble understanding things like the circulation of the blood and the heart's role in pumping it round. Carey quoted Donne's lines to a class of 30 undergraduates in their final year reading English at Oxford:
"Knows't thou how blood, which to the heart doth flow,
Doth from one ventricle to the other go?"
Carey asked them how, as a matter of fact, the blood does flow. None of the thirty could answer, and one tentatively guessed that it might be 'by osmosis'. The truth — that the blood is pumped from ventricle to ventricle through at least 50 miles of intricately dissected capillary vessels throughout the body — should fascinate any true literary scholar. And unlike, say, quantum theory or relativity, it isn't hard to understand. So I tender a more charitable view than Professor Carey. I wonder whether some of these young people might have been positively turned off science.
Last month I had a letter from a television viewer who poignantly began: "I am a clarinet teacher whose only memory of science at school was a long period of studying the Bunsen burner." Now, you can enjoy the Mozart concerto without being able to play the clarinet. You can be a discerning and informed concert critic without being able to play a note. Of course music would come to a halt if nobody learned to play it. But if everybody left school thinking you had to play an instrument before you could appreciate music, think how impoverished many lives would be.
Couldn't we treat science in the same way? Yes, we must have Bunsen burners and dissecting needles for those drawn to advanced scientific practice. But perhaps the rest if us could have separate classes in science appreciation, the wonder of science, scientific ways of thinking, and the history of scientific ideas, rather than laboratory experience.
It's here that I'd seek rapprochement with another apparent foe of science, Simon Jenkins, former editor of The Times and a much more formidable adversary than the other journalists I've quoted, because he has some knowledge of what he is talking about. He resents compulsory science education and he holds the idiosyncratic view that it isn't useful. But he is thoroughly sound on the uplifting qualities of science. In a recorded conversation with me, he said:
I can think of very few science books I've read that I've called useful. What they've been is wonderful. They've actually made me feel that the world around me is a much fuller . . . much more awesome place than I ever realized it was . . . I think that science has got a wonderful story to tell. But it isn't useful. It's not useful like a course in business studies or law is useful, or even a course in politics and economics.
Far from science not being useful, my worry is that it is so useful as to overshadow and distract from its inspirational and cultural value. Usually even its sternest critics concede the usefulness of science, while completely missing the wonder. Science is often said to undermine our humanity, or destroy the mystery on which poetry is thought to thrive. Keats berated Newton for destroying the poetry of the rainbow.
Philosophy will clip an Angel's wings,
Conquer all mysteries by rule and line,
Empty the haunted air, and gnomed mine —
Unweave a rainbow . . .
Keats was, of course, a very young man.
Blake, too, lamented:
For Bacon and Newton, sheath'd in dismal steel, their terrors hang
Like iron scourges over Albion; Reasonings like vast Serpents
Infold around my limbs . . .
I wish I could meet Keats or Blake to persuade them that mysteries don't lose their poetry because they are solved. Quite the contrary. The solution often turns out more beautiful than the puzzle, and anyway the solution uncovers deeper mystery. The rainbow's dissection into light of different wavelengths leads on to Maxwell's equations, and eventually to special relativity.
Einstein himself was openly ruled by an aesthetic scientific muse: "The most beautiful thing we can experience is the mysterious. It is the source of all true art and science", he said. It's hard to find a modern particle physicist who doesn't own to some such aesthetic motivation. Typical is John Wheeler, one of the distinguished elder statesmen of American physics today:
[W]e will grasp the central idea of it all as so simple, so beautiful, so compelling that we will all say each to the other, 'Oh, how could it have been otherwise! How could we all have been so blind for so long!'
Wordsworth might have understood this better than his fellow romantics. He looked forward to a time when scientific discoveries would become "proper objects of the poet's art". And, at the painter Benjamin Haydon's dinner of 1817, he endeared himself to scientists, and endured the taunts of Keats and Charles Lamb, by refusing to join in their toast: "Confusion to mathematics and Newton".
Now, here's an apparent confusion: T H Huxley saw science as "nothing but trained and organized common sense", while Professor Lewis Wolpert insists that it's deeply paradoxical and surprising, an affront to commonsense rather than an extension of it. Every time you drink a glass of water, you are probably imbibing at least one atom that passed through the bladder of Aristotle. A tantalizingly surprising result, but it follows by Huxley-style organized common sense from Wolpert's observation that "there are many more molecules in a glass of water than there are glasses of water in the sea".
Science runs the gamut from the tantalisingly surprising to the deeply strange, and ideas don't come any stranger than Quantum Mechanics. More than one physicist has said something like: "If you think you understand quantum theory, you don't understand quantum theory."
There is mystery in the universe, beguiling mystery, but it isn't capricious, whimsical, frivolous in its changeability. The universe is an orderly place and, at a deep level, regions of it behave like other regions, times behave like other times. If you put a brick on a table it stays there unless something lawfully moves it, even if you meanwhile forget it's there. Poltergeists and sprites don't intervene and hurl it about for reasons of mischief or caprice. There is mystery but not magic, strangeness beyond the wildest imagining, but no spells or witchery, no arbitrary miracles.
Even science fiction, though it may tinker with the laws of nature, can't abolish lawfulness itself and remain good science fiction. Young women don't take off their clothes and spontaneously morph themselves into wolves. A recent television drama is fairytale rather than science fiction, for this reason. It falls foul of a theoretical prohibition much deeper than the philosopher's "All swans are white — until a black one turns up" inductive reasoning. We know people can't metamorphose into wolves, not because the phenomenon has never been observed — plenty of things happen for the first time — but because werewolves would violate the equivalent of the second law of thermodynamics. Of this, Sir Arthur Eddington said.
If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations — then so much the worse for Maxwell's equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.
To pursue the relationship between werewolves and entropy would take me too far afield. But, since this lecture commemorates a man whose integrity and honesty as a broadcaster is still an abiding legend 30 years after his death, I'll stay for a moment with the current epidemic of paranormal propaganda on television.
In one popular type of programming, conjurers come on and do routine tricks. But instead of admitting that they are conjurers, these television performers claim genuinely supernatural powers. In this they are abetted by prestigious, even knighted, presenters, people whom we have got into the habit of trusting, broadcasters who have become role models. It is an abuse of what might be called the Richard Dimbleby Effect.
In other programs, disturbed people recount their fantasies of ghosts and poltergeists. But instead of sending them off to a kindly psychiatrist, television producers eagerly hire actors to re-create their delusions — with predictable effects on the credulity of large audiences.
Recently, a faith healer was given half an hour of free prime time television, to advertise his bizarre claim to be a 2000 year-dead physician called Paul of Judea. Some might call this entertainment, comedy even, though others would find it objectionable entertainment, like a fairground freak show.
Now I obviously have to return to the arrogance problem. How can I be so sure that this ordinary Englishman with an unlikely foreign accent was not the long dead Paul of Judea? How do I know that astrology doesn't work? How can I be so confident that the television 'supernaturalists' are ordinary conjurers, just because ordinary conjurers can replicate their tricks? (spoonbending, by the way, is so routine a trick that the American conjurers Penn and Teller have posted instructions for doing it on the Internet! See http://www.randi.org/jr/ptspoon.html).
It really comes down to parsimony, economy of explanation. It is possible that your car engine is driven by psychokinetic energy, but if it looks like a petrol engine, smells like a petrol engine and performs exactly as well as a petrol engine, the sensible working hypothesis is that it is a petrol engine. Telepathy and possession by the spirits of the dead are not ruled out as a matter of principle. There is certainly nothing impossible about abduction by aliens in UFOs. One day it may be happen. But on grounds of probability it should be kept as an explanation of last resort. It is unparsimonious, demanding more than routinely weak evidence before we should believe it. If you hear hooves clip-clopping down a London street, it could be a zebra or even a unicorn, but, before we assume that it's anything other than a horse, we should demand a certain minimal standard of evidence.
It's been suggested that if the supernaturalists really had the powers they claim, they'd win the lottery every week. I prefer to point out that they could also win a Nobel Prize for discovering fundamental physical forces hitherto unknown to science. Either way, why are they wasting their talents doing party turns on television?
By all means let's be open-minded, but not so open-minded that our brains drop out. I'm not asking for all such programmes to be suppressed, merely that the audience should be encouraged to be critical. In the case of the psychokineticists and thought-readers, it would be good entertainment to invite studio audiences to suggest critical tests, which only genuine psychics, but not ordinary conjurers, could pass. It would make a good, entertaining form of quiz show.
How do we account for the current paranormal vogue in the popular media? Perhaps it has something to do with the millennium — in which case it's depressing to realize that the millennium is still three years away. Less portentously, it may be an attempt to cash in on the success of "The X-Files". This is fiction and therefore defensible as pure entertainment.
A fair defense, you might think. But soap operas, cop series and the like are justly criticized if, week after week, they ram home the same prejudice or bias. Each week "The X-Files" poses a mystery and offers two rival kinds of explanation, the rational theory and the paranormal theory. And, week after week, the rational explanation loses. But it is only fiction, a bit of fun, why get so hot under the collar?
Imagine a crime series in which, every week, there is a white suspect and a black suspect. And every week, lo and behold, the black one turns out to have done it. Unpardonable, of course. And my point is that you could not defend it by saying: "But it's only fiction, only entertainment".
Let's not go back to a dark age of superstition and unreason, a world in which every time you lose your keys you suspect poltergeists, demons or alien abduction. Enough, let me turn to happier matters.
The popularity of the paranormal, oddly enough, might even be grounds for encouragement . I think that the appetite for mystery, the enthusiasm for that which we do not understand, is healthy and to be fostered. It is the same appetite which drives the best of true science, and it is an appetite which true science is best qualified to satisfy. Perhaps it is this appetite that underlies the ratings success of the paranormalists.
I believe that astrologers, for instance, are playing on — misusing, abusing — our sense of wonder. I mean when they hijack the constellations, and employ sub-poetic language like the moon moving into the fifth house of Aquarius. Real astronomy is the rightful proprietor of the stars and their wonder. Astrology gets in the way, even subverts and debauches the wonder.
To show how real astronomical wonder can be presented to children, I'll borrow from a book called Earthsearch by John Cassidy, which I brought back from America to show my daughter Juliet. Find a large open space and take a soccer ball to represent the sun. Put the ball down and walk ten paces in a straight line. Stick a pin in the ground. The head of the pin stands for the planet Mercury. Take another 9 paces beyond Mercury and put down a peppercorn to represent Venus. Seven paces on, drop another peppercorn for Earth. One inch away from earth, another pinhead represents the Moon, the furthest place, remember, that we've so far reached. 14 more paces to little Mars, then 95 paces to giant Jupiter, a ping-pong ball. 112 paces further, Saturn is a marble. No time to deal with the outer planets except to say that the distances are much larger. But, how far would you have to walk to reach the nearest star, Proxima Centauri? Pick up another soccer ball to represent it, and set off for a walk of 4200 miles. As for the nearest other galaxy, Andromeda, don't even think about it!
Who'd go back to astrology when they've sampled the real thing — astronomy, Yeats's "starry ways", his "lonely, majestical multitude"? The same lovely poem encourages us to "Remember the wisdom out of the old days" and I want to end with a little piece of wonder from my own territory of evolution.
You contain a trillion copies of a large, textual document written in a highly accurate, digital code, each copy as voluminous as a substantial book. I'm talking, of course, of the DNA in your cells. Textbooks describe DNA as a blueprint for a body. It's better seen as a recipe for making a body, because it is irreversible. But today I want to present it as something different again, and even more intriguing. The DNA in you is a coded description of ancient worlds in which your ancestors lived. DNA is the wisdom out of the old days, and I mean very old days indeed.
The oldest human documents go back a few thousand years, originally written in pictures. Alphabets seem to have been invented about 35 centuries ago in the Middle East, and they've changed and spawned numerous varieties of alphabet since then. The DNA alphabet arose at least 35 million centuries ago. Since that time, it hasn't change one jot. Not just the alphabet, the dictionary of 64 basic words and their meanings is the same in modern bacteria and in us. Yet the common ancestor from whom we both inherited this precise and accurate dictionary lived at least 35 million centuries ago.
What changes is the long programs that natural selection has written using those 64 basic words. The messages that have come down to us are the ones that have survived millions, in some cases hundreds of millions, of generations. For every successful message that has reached the present, countless failures have fallen away like the chippings on a sculptor's floor. That's what Darwinian natural selection means. We are the descendants of a tiny élite of successful ancestors. Our DNA has proved itself successful, because it is here. Geological time has carved and sculpted our DNA to survive down to the present.
There are perhaps 30 million distinct species in the world today. So, there are 30 million distinct ways of making a living, ways of working to pass DNA on to the future. Some do it in the sea, some on land. Some up trees, some underground. Some are plants, using solar panels — we call them leaves — to trap energy. Some eat the plants. Some eat the herbivores. Some are big carnivores that eat the small ones. Some live as parasites inside other bodies. Some live in hot springs. One species of small worms is said to live entirely inside German beer mats. All these different ways of making a living are just different tactics for passing on DNA. The differences are in the details.
The DNA of a camel was once in the sea, but it hasn't been there for a good 300 million years. It has spent most of recent geological history in deserts, programming bodies to withstand dust and conserve water. Like sandbluffs carved into fantastic shapes by the desert winds, camel DNA has been sculpted by survival in ancient deserts to yield modern camels.
At every stage of its geological apprenticeship, the DNA of a species has been honed and whittled, carved and rejigged by selection in a succession of environments. If only we could read the language, the DNA of tuna and starfish would have 'sea' written into the text. The DNA of moles and earthworms would spell 'underground'. Of course all the DNA would spell many other things as well. Shark and cheetah DNA would spell 'hunt', as well as separate messages about sea and land.
We can't read these messages yet. Maybe we never shall, for their language is indirect, as befits a recipe rather than a reversible blueprint. But it's still true that our DNA is a coded description of the worlds in which our ancestors survived. We are walking archives of the African Pliocene, even of Devonian seas, walking repositories of wisdom out of the old days. You could spend a lifetime reading such messages and die unsated by the wonder of it.
We are going to die, and that makes us the lucky ones. Most people are never going to die because they are never going to be born. The potential people who could have been standing in my place but who will never see the light of day outnumber the sand grains of Sahara — more, the atoms in the universe. Certainly those unborn ghosts include greater poets than Donne, greater scientists than Newton, greater composers than Beethoven. We know this because the set of possible people allowed by our DNA so massively outnumbers the set of actual people. In the teeth of these stupefying odds it is you and I that are privileged to be here, privileged with eyes to see where we are and brains to wonder why.
There is an appetite for wonder, and isn't true science well qualified to feed it?
It's often said that people 'need' something more in their lives than just the material world. There is a gap that must be filled. People need to feel a sense of purpose. Well, not a BAD purpose would be to find out what is already here, in the material world, before concluding that you need something more. How much more do you want? Just study what is, and you'll find that it already is far more uplifting than anything you could imagine needing.
You don't have to be a scientist — you don't have to play the Bunsen burner — in order to understand enough science to overtake your imagined need and fill that fancied gap. Science needs to be released from the lab into the culture.
A press release dated August 10, 1996, announced that two private foundations have granted the Seattle-based Discovery Institute nearly a million dollars to establish the Center for the Renewal of Science and Culture. The Center will sponsor conferences, disseminate research and support postdoctoral students.
Individuals associated with the Center include some familiar old-earth anti-evolutionists employed at secular colleges and universities: Stephen Meyer (philosophy, Whitworth College), John West (political science, Seattle Pacific University), Phillip Johnson (law, University of California-Berkeley), and Michael Behe (biology, Lehigh). The current crop of research fellows include William Dembski (mathematics, formerly at Princeton), Paul Nelson (philosopher, former editor of the Bible-Science Newsletter and recent University of Chicago Ph.D.), and Jonathan Wells (molecular and cell biology Ph.D. from UC-Berkeley.)
Think Tanks and University Anti-Evolutionism
The funding and deployment of the Center for the Renewal of Science and Culture is a major step towards scholarly respectability for a relatively new group of anti-evolutionists: religious conservatives based at secular universities. They are organizing (or have organized) Internet list serves and web pages, conferences, new journals (see NCSE Reports 1996 Fall; 16, p 5) and, now, think tanks.
We are witnessing the embryogenesis of what I shall call "university-based anti-evolutionism". This term, though imperfect, reflects the fact that the newer crop of old-earth, mostly "design theory" anti-evolutionists are disproportionately located in secular institutions of higher learning, rather than at the more familiar independent, not-for-profit centers such as the Institute for Creation Research, Answers in Genesis, and so on. Because most of them are not, in fact, in science departments, it would be inaccurate to refer to them as creation "scientists".
Historically, the leading anti-evolution activists have been such "young-earth" creationists as Henry Morris of the Institute for Creation Research. However, the publication of Phillip Johnson´s Darwin on Trial in 1991, encouraged the growth of a more moderate, "old-earth" anti-evolutionism which, because it accepts that the earth is ancient, is perceived by the public as being less on the fringes of science than other creationist models. Although they disagree on the age of the earth, neither old earthers nor young-earthers accept biological evolution (descent with modification) as the basis for the emergence of new species from ancestral forms. Most will accept mechanisms and processes of evolution such as natural selection, but they balk at a natural origin of new "kinds" and "basic body plans".
Phillip Johnson, a nationally-known scholar at a major secular university (Boalt School of Law at UC-Berkeley) legitimized the concerns of conservative Christians that their views were being systematically excluded from the secular institutions in which they worked. Johnson and others supporting university-based anti-evolutionism have challenged academe that if it is acceptable in academia to teach and do research from the perspective of an "ism" such as Marxism or feminism, why is it not also acceptable to argue from the perspective of Christianity? A concern of university-based conservative Christians is the increasing secularization of society and what they see as the abandonment of faith. Their own universities, they believe, are mainsprings of this tendency, and they don´t like it. They believe society is locked in a struggle between materialism and theism.
Materialism and Theism
Materialism is the view that the natural world can be explained in terms of matter, energy and their interactions. It may be expressed as a methodological rule "science is restricted to explaining the natural world through natural means", or as a broader, philosophical conclusion that, "therefore, there is no God." Theism is the belief in a supreme God, and for conservative Christians, this God must be an active participant in the running of the universe and in the affairs of humankind. But instead of arguing philosophically about the values of theism vs. materialism, the university-based anti-evolutionists use evolution as a stalking-horse. Evolution is a symbol of these conservative Christian professors´ discontent with secularism in academia and in society at large. NCSE objects to books by Johnson (Pennock 1996; Fezer 1996) and Michael Behe´s recent Darwin´s Black Box (see review by Miller 1996) not because they promote a philosophy, but because they unjustifiably attack a science.
The focus on theism vs. materialism is well exemplified by "intelligent design" (ID), the argument that some aspects of nature are "too complex" to have occurred through evolution, and thus a place must be left in science for supernatural intervention. But the practice of modern science is overwhelmingly (methodologically) materialistic: supernatural explanations are dead ends that do not lead to further understanding. University-based anti-evolutionists object to the current primacy of methodological materialism in science and request that we scrap a methodology that has worked very successfully for over a hundred years. I have frequently run into a, "but-if-it-is-the-truth, why-can´t-we-teach-it?" argument for allowing supernatural explanations into science classes. Members of the public who feel this way can now claim support from an impressive source: scholars based not just at Bible colleges, but at secular universities.
The rise of university anti-evolutionism is relatively new, and the promised hard-hitting critiques of the science of evolution have not yet appeared. ID has not influenced evolutionary biology or any other mainstream science, for example. However, although it has been inconsequential in science, university anti-evolutionism appears to be seeping into philosophy, history, "science studies", and social studies classes, in which works by Johnson, Behe, and others are being assigned and read. As valuable as it may be for understanding the social context of late 20th-century science to read these modern critiques, the question arises as to whether a philosopher or a sociologist has sufficient scientific background to see and to articulate to students how these books and articles fail as science.
What will be the future influence of university-based anti-evolutionism? How will its rise affect the current struggle to keep evolution in the schools? Currently, resources and influence of the Center for Renewal of Science and Culture pale next to the vigorous proselytizing of the Institute for Creation Research, the Bible Science Association, or Answers in Genesis. But there is another, more long-term way that university anti-evolutionism may affect the creation/evolution controversy: To the extent that anti-evolutionism spreads throughout the secular university community, its major influence is likely to be in training the next generation of teachers (and school board members and state legislators) to be suspicious of evolution. It does not matter that university-based anti-evolutionism is not rooted in science departments: most students take few courses in these department anyway. If university-based anti-evolutionism expands, there will be ample opportunity for them to learn erroneous science in non-science courses.
University scientists should watch for opportunities to open channels of communication when colleagues in other disciplines assign readings that distort or misrepresent science, such as Johnson´s Darwin on Trial or Behe´s Darwin´s Black Box. The point that should be made is that although the philosophical issues raised in these books are legitimate subjects for debate, the science is often substandard, and if the books are used, scientific errors should be noted for the student.
As an example, if a history teacher wanted to discuss the historical issue of the divine right of kings, he would be unlikely to use a source that claimed that ancient Egyptians ruled 15th-century France -- the historical issue could be discussed, but the historical example itself is just bad history. Similarly, Johnson brings up issues of philosophical interest, but Darwin on Trial is not a source one should use to learn the science of evolution (see Scott and Sager 1992, Scott, 1993).
Ironically, from the standpoint of evolution education, it is far preferable to have anti-evolutionary ideas expressed and debated at the university than in the local school board meeting. At least at the college level, individuals can be found who can show the scientific flaws in anti-evolutionist arguments, as has been done with Behe´s and Johnson´s books.
Fezer K. Is science´s naturalism metaphysical or methodological? Creation/Evolution 1996 Winter; 16(2) nr 39:31-35.
Johnson PE. Darwin on trial. Washington, DC: Regnery Gateway; 1991.
Miller KR. Book review of Darwin´s black box: The biochemical challenge to evolution by Michael J Behe.
Pennock R. Naturalism, creationism, and the meaning of life. Creation/Evolution 1996 Winter; 16(2) nr 39:10-30.
Scott EC. Book review of Darwin on Trial by Phillip E Johnson. Creation/Evolution 1993 Winter; 13(2) nr 33:36-47.
Scott EC, Sager TC. Book review of Darwin on Trial by Phillip E Johnson. Creation/Evolution 1992 Winter; 12(2) nr 31:47-56.
In Ireland, the Irish say, there is no future, only the past happening over and over — a sorrowful statement of resignation and frustration that reflects centuries of near-intractable sectarian and political strife. I sometimes feel the same way about the evolution/creation conflict: One hundred and fifteen years after Darwin's death there is no future, only the same, tired creationist arguments repeated over and over and the continuing expenditure of precious time and money to combat creationist nonsense — resources that could be applied to other problems.
Perhaps historian Gary Wills (1990) was correct when he wrote that the evolution/creation debate will never subside because "the Bible will never stop being the central book of Western culture." Richard Lewontin (1996) may also be right when he asserts that the scientific community has made little progress in convincing the public to embrace a scientific world view — including evolution — because hubris has blinded scientists to the fundamental distinctions between "elite" and "popular" culture. I suspect, however, that the cultural and philosophical reasons for the staying power of creationism and the intransigence of its proponents matter little to the average high school biology teacher when he or she is attacked for teaching evolution and unwittingly becomes a central player in a political struggle for control of the curriculum.
Unlike those of us who generally work behind the lines, as it were, dealing with the more global (read "safe") aspects of the evolution/creation conflict, teachers are at the front, dealing with direct challenges to their teaching from real students and real parents who have immediate questions and immediate demands. Some typical examples include:
Discussions with teachers across the country confirm that challenges to the teaching of evolution are commonplace. There is evidence of correlation between such challenges and student attendance at events such as "Back to Genesis," a week-long seminar sponsored by the Institute for Creation Research and devoted to evolution-bashing and "creation science". For example, Danny Phillips, the Jefferson County, Colorado, high school student who challenged the use of the video The Miracle of Life and the BSCS textbook Biological Science: An Ecological Approach, attended a "Back to Genesis" seminar in Manitou Springs, just west of Colorado Springs (Matsumura 1996a, 1996b). There also is evidence that challenges to evolution increase in any given community following evolution/creation debates, a good reason to heed Eugenie Scott's advice that scientists inexperienced in such events should decline invitations to participate (Scott 1996).
Three unfortunate facts conspire to put most high school biology teachers at a severe disadvantage when challenges to evolution arise. First, few teachers are acquainted with the ever-evolving range of creationist arguments. Second, most teachers do not have enough background and training in the range of subjects and disciplines pertinent to evolution to respond effectively when parents or students confront them with those arguments. Third, teachers get little help from their administrators when creationists begin to make noise, because most administrators themselves do not understand evolution or its importance to biology cause they do not like controversy. Most administrators are more likely to compromise, or even capitulate completely to creationist demands, than they are to support their teachers or to protect the integrity of science. Many teachers, for example, have told me that their principals suggest that "it would be okay not to get to evolution" during the course of the school year, and others have told me that they simply avoid evolution because they do not want the controversy themselves, specially when their administrators fail to support them. It is, in fact, quite easy for teachers to avoid evolution, because most biology textbooks relegate the topic to one or two chapters, often near the end of the book, and do not integrate evolutionary perspectives throughout the program.
Against this distressing backdrop, the board of directors of the National Association of Biology Teachers (NABT) appointed an ad hoc committee to prepare a new statement on the teaching of evolution. During the fall of 1994, the six-person committee, chaired by Dr. Richard Storey, chairman of biology at Colorado College, produced a document intended to:
Following approval by the NABT board in March, 1995, the statement appeared in January, 1996, in the Association's journal (The American Biology Teacher 1996 Jan; 58, pp 61-2) and in the second edition of Voices for Evolution published by NCSE in 1996.
NABT — comprising approximately 8,000 professionals who teach at the middle school, high school, and college levels — is the only professional society devoted exclusively to the teaching of biology. It is appropriate, therefore, that the society be on record with an unequivocal statement about the importance of teaching evolution, and it is imperative that the scientific and educational communities embrace the statement and support those teachers who put themselves on the line to defend the integrity of biology. The immediate future of the evolution/creation conflict likely holds few surprises, but the nation's biology teachers — and creationists — need to know that someone will be watching and responding as the past repeats itself over and over.
Lewontin R. Billions and billions of demons. New York Review of Books 1997 Jan 9; 44(1): 28-32
Matsumura M. Evolution challenged in Colorado's largest school district. NCSE Reports 1996 Summer; 16(2): 21.
Matsumura M. Updates and short takes. NCSE Reports 1996 Fall; 16(3): 10.
Matsumura M, ed. Voices for evolution. rev ed. Berkeley, CA: National Center for Science Education; 1995.
Scott E. Debates and the globetrotters. Creation/Evolution 1994 Winter; 14(2) nr 35: 22-6.
Wills G. Under God: Religion in American Politics NY: Simon and Schuster; 1990.
A large, industrial Northern state may be about to banish the word "evolution" from its science curriculum standards. Acting on a mandate from the state legislature, the Illinois Board of Education has developed new Learning Standards for a number of subjects, including science. Learning Standards are supposed to define appropriate content for meeting a number of goals, including the expectation that students will come to "Understand the fundamental concepts, principles, and interconnections of the life, physical, and earth/space sciences" (State Goal 12). Yet evolution, which has been listed as one of the major unifying concepts organizing the National Science Education Standards issued by the National Academy of Science, is never specifically mentioned in Goal 12 or anywhere else in Illinois' proposed learning standards.
NCSE members who contacted Board of Education staff learned that there had been no mention of evolution in the first public draft of the Standards, but revision teams added a reference in response to extensive public comment, as well as the recommendations of expert reviewers. However, according to a letter from the Superintendent of Education that was released with the final "Proposed Learning Standards", members of "an External Review Team consisting of parents, educators, business people, civic leaders, and representatives of family groups ... recommended... that no controversial content which was not included in the draft previously disseminated for public review would be included"... (italics in original). Goal 12, Standard A now reads, "Know and apply concepts that explain how living things function, adapt, and change."
As NCSE member David Bloomberg commented at the June 11 meeting of the Board, the vague wording of the standard can refer to individual or short term changes "like my blood pressure changing during the day." While "benchmarks" expanding upon the standards refer to evolutionary processes and supporting evidence, the fact is that the "e" word never appears. Teachers who use the most accurate term to describe what they are teaching are given no protection from parental complaints. Worse, the External Review Team's report says only that the state "could provide examples and support materials to assist local districts in deciding when, where, and how to teach these [omitted, "controversial"] subjects. Since evolution is one of the topics omitted from the revised "Draft Standards" before they were submitted as "Proposed Standards", districts that choose to teach it could be forced to rely on limited, local resources.
At press time, the Board of Education is again receiving comments from the public. It is impressive that there had been so much public support for evolution, and if there is more such support, the Board could decide to override the Review Team’s recommendations. If they do not, it is likely that evolution education will become a local option, and many Illinois students will be denied the opportunity to learn about the major theory unifiying biological knowledge.
In April 1997, the Institute for Human Origins (IHO), a not-for-profit paleoanthropology research institution located in Berkeley, CA, completed negotiations with Arizona State University to move to that university in July of 1997. NCSE Supporter Donald C Johanson will remain Director of the Institute, and senior staffers William H Kimbel and Kaye Reed will hold dual positions as Institute scientists and members of the ASU Department of Anthropology. Also moving to Arizona with IHO are geochronologist Robert Walker and paleoanthropologist Eric Meikle and support staff.
The move is viewed by both IHO and ASU as being to their mutual advantage: ASU receives a prestigious research institution and IHO receives partial financial stability and the many administrative and scholarly advantages of a university affiliation. Johanson and his staff were looking forward to mentoring graduate students.
Of particular interest to NCSE members, however, is the response of Arizona Regent Kurt Davis when asked to approve the University's association with IHO. Although voting to approve the arrangement, he added an amendment that ASU would "come back with a plan that would implement and examine the use of courses to offer alternative theories, as well." The ASU newspaper reported that, in a memorandum to other regents, Davis expressed concern that "we will expend tax dollars to continue research and create debate from only one perspective" (State Press, April 28, 1997). The Board of Regents voted unanimously to approve Davis' motion.
Letters to the editor in local Tempe papers varied from support to criticism of the regents' decision, some assuming it would require the teaching of creation "science" at ASU. As NCSE members know, "alternative theories to evolution" is a popular euphemism for creation science, but the wording of the resolution is vague. Reportedly, both the religious studies program and science departments are uninterested in presenting "alternatives to evolution". Administrators appear to be uncertain as to what to do about Davis' suggestions, which also raises questions regarding Regents' authority to determine curricula.
On June 16, 1997, a major weekly magazine, US News & World Report published "The Geophysics of God" reporting claims that a sophisticated computer program written at the Los Alamos National Laboratory (LANL) and "used by geophysicists around the world... proves the Bible is correct" (Chandler 1997). By mid-July NCSE had received copies of letters submitted to a large state textbook commission making similar claims. One letter said that textbooks should include "Flood geology as a theory for mass extinction... [since] this idea is currently being studied in some of the national laboratories in New Mexico"; another letter cited a sophisticated-sounding argument used by geophysicist John Baumgardner, the scientist profiled in the article, claiming that different methods for dating ancient rocks yield different results.
NCSE members need to know the flaws in these arguments because this "evidence against evolution" may appear in an opinion piece in your local newspaper, or, worse, a proposal to your local board of education. NCSE has consulted several geologists for detailed comments on the US News article. Excerpts from the article are presented in italics followed by responses from scientists working in the relevant fields.
Terra [a computer program for modeling the flowing movement of the earth's mantle]...exists because its creator, John Baumgardner, is a fundamentalist Christian who believes, in accordance with the Bible, that the Earth was created by God less than 10 000 years ago...[and] created Terra expressly to prove that the story of Noah and the flood...happened as the Bible tells it".
There are good scientific reasons for developing a computer model of mantle flow, independent of Baumgardner's motivation. His views do not represent those of LANL. According to Dr. Jerry M Boak, another geologist at LANL, "Creationist modeling was distinctly not part of the work scope. Scientific publications of research using the Terra program have nothing to do with ...flood geology..." (For the history and the results of this research, readers should examine Baumgardner 1985, Bunge and Baumgardner 1995, or Bunge, Richards, and Baumgardner 1996).
Boak requested further information from Dr. Chick Keller, Director of the Institute for Geophysics and Planetary Physics at LANL, who explained that Baumgardner had originally written Terra as a part of his doctoral dissertation. According to Keller "...[Terra] fell into disfavor when it could not adequately reproduce results [derived] from other 3-D spherical mantle convection codes." Keller told NCSE that Peter Bunge and other workers later "improved it considerably, to the point that the community now accepts it as [reasonable].... [However], [Baumgardner's] version is somewhat different from [Bunge's] and still needs benchmarking — that is, testing against other codes to assure that it gives reasonable answers to well-defined problems."
Not only did he come up with a tool used by geophysicists around the world but his "numerical code" actually proves the Bible is correct. Or at least in Baumgardner's view it does.... Terra proves that this is true — or, more precisely, that it could be true, provided one accepts certain assumptions.
Computer models do not prove anything; they can help work out the consequences of certain assumptions. One can feed a computer program data about cheese and rats and find out how large a rat must be in order to take crater-sized bites out of a moon made of green cheese, then illustrate the process with realistic graphics. This would not prove that the moon is made of cheese or that there are giant, space-going rats. The article's author admits that Baumgardner's explanation of the flood "contradicts almost every existing piece of evidence" (emphasis added). For example, accepting Baumgardner's assumptions would include changing the values of known physical constants such as rates of radioactive decay.
Keller commented that it was unfortunate that "The article gave the impression that one need only change a few numbers like viscosity and you can get anything from mantle convection to continents' zooming around." He added that there are important questions about other variables that Baumgardner's model does not consider. As for the computer program itself, Baumgardner's "Terra" is not the only mantle modeling program in use and, Keller commented, while Bunge and possibly some other scientists have gained "considerable respect and support" for their use of some versions, "I don't think it's very widely used."
Baumgardner believes that around 6000 yearsago,...[God] caused an enormous blob of hot mantle material to come rushing up at incredible velocity through the underwater midocean ridges. The material ballooned, displacing a tidal wave of sea water over the continents.... Then, after 150 days (Genesis7:24), the bubble retreated with equal speed into the Earth.
According to University of New Mexico geologist John W Geissman, this series of events would create "an enormous volcanic province in a single region. So, where is it??" Keller added, "Blobs don't just emerge and retreat...; one needs a source mechanism.... Current blobs which emerge, for example, out of a volcano or midocean ridge, are rather local and short lived...."
[A]nd the continents began re-emerging above the water, sending the runoff back to the oceans at around 100 miles an hour....Baumgardner says that this runoff would have been sufficient to create the Grand Canyon and other massive geologic features and to deposit the various sedimentary layers in about one week.
The phrase "various sedimentary layers" glosses over a great variety of geological formations, many of which could not possibly have been deposited in one week, least of all by currents traveling one hundred miles per hour. Examples of these include sediments that settled in still water, those transported by wind, and those formed by evaporation or precipitation of dissolved chemicals (Strahler, p 61, 170). Not only does one week provide too little time for sediments to be deposited, Baumgardner does not explain inter bedding of sediments clearly formed by different processes; for example, a layer formed of wind-borne particles sandwiched between layers of sediment that had settled from still water.
The US News article also does not say what kind of land surface was being eroded. Arthur Strahler's comments on erosion by forty days and forty nights of rain apply to Baumgardner's model of streams rushing back to the ocean: "Fully lithified, hard, dense rock — such as ... [various] kinds of igneous and metamorphic rock... — could withstand forty days and nights of torrential rainfall with scarcely a measurable quantity of erosional removal.... Even on the assumption that a thick (100-meter) layer of decayed rock (saprolite) was available... it would be woefully inadequate to supply the quantity needed to form all existing Proterozoic and younger sedimentary and metasedimentary rocks" (Strahler, p 201). Simply put, sudden erosion cannot explain the sheer volume of material in the earth's "sedimentary layers".
Almost all physicists calculate the age of the planet at 4.6 billion years because they assume that mantle viscosity...has been consistent throughout time and so use the value that applies today. They add other ingredients like the speed of the tectonic plates... and arrive at the conclusion that one full deformation cycle of the mantle occurs about every hundred million years, giving the 4.6 billion figure. But Baumgardner says scientists wrongly assume that geology happens consistently,...."If you look at the geological record," he insists, "there are fingerprints of catastrophe everywhere one looks."
G Brent Dalrymple, author of The Age of the Earth, told NCSE, "The viscosity of the planet does not enter into calculations of the age of the earth. There is no way to calculate the age of Earth from plate tectonics or from mantle convection." Boak added, "Certainly there are catastrophes in the geologic record, but they aren't the catastrophes Baumgardner describes, and they don't represent the fingerprints of God spinning up a planet last week."
Baumgardner...notes, first, that different radiometric dating methods give vastly different ages. To date rock, geologists commonly use three types of unstable (radioactive) 'parent' isotopes — samarium, rubidium, and potassium — which decay into stable 'daughter' elements.... But different isotopes yield different dates for the same rocks. As an example, Baumgardner points to the Cardenes [sic]basalt, a Precambrian volcanic rock found in the Grand Canyon's inner gorge.
In fact not three, but at least seven isotopes are used for dating rocks (Dalrymple 1991, p 80). More significantly, Baumgardner simply misinterprets what is to be learned by comparing different isotopic dates.
Boak pointed out that in the Cardenas rock "The sequence of these dates [found by the different dating methods] is exactly what would be expected for such old rock." Rocks can be altered by heating or melting, and Dalrymple commented, "Alteration is readily visible in thin sections of the [Cardenas] rock." The different dating methods date different events in the history of the rock and Dalrymple added, "The results tell us that this particular rock is not a reliable chronometer, but say nothing about the dating methods themselves.... There are many more instances of agreement than disagreement; if Baumgardner finds a wristwatch that doesn't work would he conclude that all watches and clocks are unreliable?" When rocks are altered by heating, the geological clock is reset so that, as Boak put it, "The Cardenas rocks ... may be more like modern stopwatches, which may record several lap times. Because the degree of heating required to reset the various geochemical clocks is different, we may be able to identify several different events."
The science Baumgardner uses to account for these extraordinary happenings is a sort of niche physics called runaway subduction ...[which] posits that the potential energy in the cold, heavy crust of the Earth is like the potential energy in a rock held above the ground. Drop the rock, and its potential energy is turned by gravity into kinetic energy, and into heat when it hits the ground. As gravity pulls the rock, so it pulls the gigantic, heavy plates of ocean floor under the continents into the hotter, lighter mantle, which is silicate rock.
As the plates deform the surrounding rock, the mechanical energy of deformation is converted into heat, creating a superheated 'envelope' of silicate around the sinking ocean floor. Silicate is very sensitive to heat, so it becomes weaker, allowing the plates to sink faster and heating the envelope still further, and so on, faster and faster. As the plates pull apart, the gap between themgrows into a broadening seam in the planet. This sends a gigantic bubble of mantle shooting up through these ridges; [w]hich displaces the oceans; [w]hich creates a huge flood.
"Fringe" physics might be a better description. The article does go on to quote another geophysicist who pointed out that one would have "to believe that by some miracle the diffusivity of the Earth was different before we learned to measure it;" in fact, the miracle would have to increase thermal diffusivity by a factor of 10,000. Boak commented, "The problem with his work on 'runaway subduction' is that the frictional heating he requires to accelerate subduction may not continue, given the reduced viscosity of the subducting materials as they are heated. To my knowledge, this aspect of his model has never survived a peer review by others in ... mantle modeling."
[Baumgardner] cites the common geological feature of erosional channels, like the sunken rivers running through Zion National Park. The walls of these channels, created by rainwater eroding uplifted terrain, show the cross sections of sedimentary layers laid down over millenniums [sic]. But while the evidence of erosion and sedimentation is all around (the Mississippi Delta, the Ganges taking soil from the Himalayas), surprisingly few erosional channels can be seen in the sedimentary layers themselves.
Just as it is erroneous for Baumgardner to state that sediments clearly formed by different processes could have been deposited in a single flood, it is erroneous to lump together many types of channels. Besides, as Dalrymple points out, the article does not state that there were no such channels, but that there were "too few". Yet we are not told how many would be "enough", or why.
Another piece of evidence [Baumgardner] points to is the fact that coal — fossilized plant matter — is found in concentrated seams rather than spread out, as forests generally are. This indicates to Baumgardner that a huge mass of water — a flood — swept floating trees together, depositing them in thick layers.
Baumgardner's argument is a red herring. There are many types of forest environment, not all of them conducive to the initial steps of coal formation. Coal seams originated in swamps in deltas, and their boundaries are those of the deltas. Besides, layers of marine and non-marine sediments can be found between layers of coal, and Baumgardner neither asks how this alternation of layers could occur nor offers an explanation. While the standard geological explanation accounts for these alternating layers, Baumgardner's flood does not. The flood currents bearing trees would have had to alternate quickly with currents moving in a different direction, carrying different materials. Currents moving as swiftly as 200 km/hr would have to alternate approximately every half hour, not allowing enough time for rafts of water-borne trees to settle between the other strata (Strahler, p 218-221). Furthermore, according to Dr. Steven M Getty of the University of New Mexico, fast-moving water currents pick up large quantities of sand and gravel, and mix them with organic matter, while many large coal seams are almost purely organic, often preserving details of plant structure too well to be consistent with Baumgardner's model.
Baumgardner himself says, "The only way to square the radiometric data with a flood that caused all these changes is to conclude that one aspect of the catastrophe was rapid radioactive decay." ...This is not impossible.
As the article itself comments, this is only possible in "a Through-the-Looking-Glass world where nothing is as it seems and no scientific principle — from gravity and electromagnetism on down — exists as it exists today." Moreover, this objection can't be met by calling on miracles, not if one considers other events that would have occurred in Baumgardner's scenario — something the article does not do. For example, Dalrymple points out that "If one 'speeded up' 4.5 billion years of radioactive decay into just a few years, then the heat released over such a short time would melt and probably vaporize the Earth." In effect, readers are being told that it is "not impossible" for Noah's Ark and its inhabitants to have withstood the melting of a planet. Was the "ocean" on which the ark floated one of molten lava (which should have burned the Ark to a cinder), or is the earth supposed to have recondensed and generated new plant life while the Ark's passengers waited?
[T]here is universal agreement that Terra, created to prove the Bible literally true, is one of the most useful and powerful geological tools in existence. "Baumgardner is seen as one of the world leaders in numerical models of mantle convection," says Hager. Agrees Gerald Schubert of the University of California - Los Angeles Department of Earth and Space Sciences: "As far as the code goes, Baumgardner is a world-class scientist."
NCSE wrote to Hager and Schubert to ask about their remarks attributed to them. Schubert replied, who explained, "I did not agree with what Hager [reportedly] said. I simply stated that John Baumgardner had written a state-of-the-art numerical code to study mantle convection.... In no way can John's numerical code say anything about the possible validity of a literal biblical view of creation." Hager, too, told NCSE that he had only been commenting on the computer code, and had not in any way endorsed Baumgardner's opinions.
It is Baumgardner's "scientific" claims that are most likely to be repeated by advocates of "creation science", especially now that coverage in a national weekly has given Baumgardner a much larger audience than the Institute for Creation Research Graduate School where he is an adjunct faculty member. However, the article also underplays the manner in which Baumgardner "takes issue with the teaching of evolution in public schools". He is not just a local "rabble-rouser"; he has been appointed to the committee that is working to develop "performance standards" measuring what New Mexico's school-children have learned about science. These standards are supposed to redress the omission of evolution from New Mexico's content standards (RNCSE, 17 p 4, 17 p 8-9), but Baumgardner's participation in the committee might prevent that from happening.
The US News article concludes, "Belief does not need the blessing of science. But to John Baumgardner ... apparently it does." That, of course, is a personal choice. But as a matter of public policy, public school science education should not be required to receive the blessing of unscientific beliefs.
[With thanks to (in alphabetical order) Jerry M. Boak, G. Brent Dalrymple, John W. Geissman, Stephen R. Getty, Chick Keller, and Brad Hager for their comments and, in some cases, detailed explanations.]
Baumgardner J. Three-dimensional treatment of convective flow in Earth's mantle. Journal of Statistics in Physics 1985; 39:501-11.
Bunge P, Baumgardner J. Mantle convection modeling on parallel virtual machines. Computers in Physics 1995; 9: 207-15.
Bunge H-P, Richards MA, Baumgardner JR. Effect of depth-dependent viscosity on the planform of mantle convection. Nature 1996; 379: 436-8.
Chandler B. The geophysics of God. US News & World Report 1997 Jun 16; 122:55-8.
Dalrymple GB. The age of the earth. Stanford (CA): Stanford University Press; 1991.
Strahler AN. Science and earth history : The evolution/creation controversy. Buffalo (NY): Prometheus Books; 1987.
Anti-evolutionists have asserted that evolutionary biology lacks predictive power (Gish 1979; Johnson 1991; Morris 1974, 1989). They still cite Karl Popper's early suggestion that evolutionary theory is untestable because it cannot be used to make predictions, despite the fact that this view has been rejected by philosophers of science and that Popper himself unequivocally reversed this opinion (1978:344-5). Such assertions that evolutionary theory is unpredictive ignore the power of the comparative method in testing both alternative hypotheses and models of evolutionary processes as well as the pervasive implicit tests of evolutionary theory in every aspect of modern biological science. In this paper I will discuss briefly how biologists across disciplines use evolutionary theory as a foundation for understanding biological systems. Next I will give a few examples of how evolutionary biologists test hypotheses about specific modes of selection and evolution. Finally I will discuss, in detail, an example of the extremely successful predictive power of one evolutionary hypothesis.
"Nothing in biology makes sense except in the light of evolution" (Dobzhansky 1973). Accordingly, biochemists, geneticists, ecologists and medical researchers do not choose their hypotheses randomly. A hypothesis must first be logically consistent to be worth testing. An underlying part of the logic in most biological hypotheses is that the system under study is adaptive, selectively neutral or even maladaptive (but maladaptive in ways that we can understand based on conflicting biological demands or novel circumstances). Maladaptive characters are studied in the context of their unusual nature and the surprise they pose in light of an apparently well adapted biological world. When molecular biologists investigate complex biochemical pathways, gene regulators, or carrier proteins, they are working under the paradigms that the molecules in question serve an adaptive function. Biochemists do not test hypotheses about the beauty of a molecule but about its function (Stryer 1995).
The fact that not all biological systems are adaptive can be confusing, and this confusion has misled some scientists to conclude that evolution is, therefore, irrelevant to understanding particular maladaptive systems. However, evolutionary theory is not limited to explaining adaptations. For example, simple adaptive hypotheses cannot explain senescence, but the study of age-related changes in the potential for future reproduction (reproductive value) and of (pleiotropic) genes that produce a number of different traits has given us the clearest understanding of why senescence has evolved differently in different organisms (Alexander 1987; Charlesworth and Hughes 1996; Williams 1957). Cancer is also best understood as the result of selection working at the cellular level and in conflict with competing selective forces at the individual level (Tomlinson and others 1996).
Biologists across disciplines also indirectly test phylogenetic hypotheses and assumptions when choosing test organisms. When medical researchers want to test the effects of a new drug or treatment, they recognize that the phylogenetic relationship between the model experimental organism and humans is relevant to interpreting results and judging either the efficacy or danger to humans. Results based on rodent studies are given less weight than primate studies because of our more distant common ancestry and the greater divergence that has resulted.
Direct tests and predictions about the mode of evolution are conducted daily by evolutionary biologists and population geneticists. However, an arbitrary distinction between micro- and macro-evolutionary processes has been used to devalue tests of evolutionary hypotheses in selection experiments or in insect population cages (where insects can hatch, breed and die for hundreds of generations in the course of an experiment). Population geneticists make predictions and test hypotheses about the mode of evolution. In population cages, petri dishes or growth media, population geneticists test hypotheses about evolutionary change in controlled populations (for example Carson and others 1994; Goodnight and Stevens 1997; Templeton 1996). In wild populations, population geneticists look at gene frequencies within species or populations in order to test hypotheses about relatively recent evolutionary events (for example Crandall and Templeton 1993; Routman and Templeton 1994; Templeton and others 1993).
Ecologists and conservation biologists use evolutionary theory to interpret the relationships we see in wild communities and to predict how those communities will be affected by changes and environmental pressures (for example Georgiatis and others 1994; Losos and others 1997; Templeton and Read 1994). While much of current ecological theory is complex and multivariate, MacArthur and Wilson (1967) were able to make rather simple and testable predictions about the diversity of species on islands of different sizes and distances from mainland. In addition, behavioral ecologists make predictive hypotheses about the trends we expect to see across a wide variety of taxa (Alexander and others 1979; Harvey and Pagel 1991; Martins 1996; Ryan 1990).
In the examples cited above, predictions from and tests of evolutionary theory fit into two general categories: how evolution works in specific cases and circumstances, and what evolution has produced in response to particular circumstances. Ecologists, phylogeneticists, and population geneticists are interested in the subtle details of how evolution works. In testing adaptive hypotheses about how their particular biological system works, other biologists are testing predictions of what evolution has produced. The underlying paradigm is that evolution has generally produced adaptive systems and structures.
The uses of evolutionary theory to make these various predictive hypotheses have also been criticized as being post hoc since we already know what has evolved but cannot do simple experiments and predict what will evolve. This line of reasoning not only ignores all the population cage experiments in evolutionary biology but, if true, would lead to the classification of astronomy as unscientific as well, since we cannot manipulate the cosmos. The multitude of minute, precise predictions about the locations of known planets and stars in tomorrow night's sky are analogous to the specific predictions that are made in comparative tests by evolutionary biologists.
Occasionally, however, more striking predictions are made. In 1845 John Couch Adams and Urbain Jean Joseph Leverrier both predicted the presence of an unseen planet which affects the orbit of Uranus. It was not until the following year that Neptune was discovered as they had predicted.
Richard D Alexander has made a similarly striking prediction based on first principles of the evolution of social behavior. Although common in social insects, eusociality—the social system with a queen and sterile workers—was unknown in any other taxa. Under the appropriate set of conditions, Alexander predicted, evolution ought to produce a eusocial vertebrate, even though eusociality in the naked mole-rat (or any other vertebrate) was unknown at the time.
The roots of Alexander's prediction go back to questions raised by Darwin over 100 years prior. In his chapter titled "Difficulties with the theory" Darwin addressed the problem that sterile workers in social insect colonies pose for natural selection. How could natural selection cause differences between queen bees and workers if the workers are sterile? Darwin guessed that in these cases selection is acting between families or hives.
In 1964 William Hamilton formalized this idea of kin selection and suggested that eusocial colonies with queens and workers have evolved many times in the ants, bees, and wasps because of their unusual genetic system. In these hymenopteran insects, males have one set of chromosomes (haploid) and females have two sets (diploid); this is called haplodiploidy. As a consequence of this genetic peculiarity, sister workers in these insects are more closely related to each other than they would be to their own offspring. Consequently, they contribute to the propagation of a greater proportion of their genes by helping to rear siblings than by producing offspring themselves.
In 1974 entomologist and evolutionary theorist Richard Alexander argued that "subsocial" behavior (that is parental care) and the opportunity for parental manipulation were even more powerful factors in the evolution of social behavior in insects (Alexander 1974). Across taxa, parental behavior correlates much more strongly with eusociality than does haplodiploidy (Andersson 1984; Alexander and others 1991). Alexander's critics argued that if parental care is a crucial precursor to eusociality, we should expect eusociality to have also evolved among the highly parental vertebrates: birds and mammals. Alexander could have pointed out that there are far fewer species of birds and mammals than there are species of insects, or that birds and mammals have only existed for 160 million and 250 million years respectively (Eisenberg 1981; Welty 1979) while insects have existed for 350 million years (Borror and others 1989). Instead he asked himself what characteristics a eusocial vertebrate would have if it had evolved.
Alexander based his answer on his understanding of the selective forces involved in the evolution of insect eusociality and hypothesized a eusocial vertebrate. He created a 12-part model for a eusocial vertebrate, based on this body of theory. He had no idea that a mammal with these characteristics existed.
Alexander predicted that a eusocial vertebrate's nest should be (1) safe, (2) expandable, and (3) in or near an abundance of food that can (4) be obtained with little risk. These characteristics follow from the general characteristics of primitive termite nests inside logs. The nest must be safe or it will be exploited as a rich food source for predators. It must be expandable so that workers can enhance the value of the nest. It must be supplied with safe abundant food so that large groups can live together with little competition over food or over who must retrieve it.
The limitations of the nest characteristics suggested that the animal would be (5) completely subterranean because few logs or trees are large enough to house large colonies of vertebrates. Being subterranean further suggested that the eusocial vertebrate would be (6) a mammal and even more specifically (7) a rodent since many rodents nest underground. The primary food of the hypothetical vertebrate would be (8) large underground roots and tubers because the small grassy roots and grubs that moles feed on are so scattered that they are better exploited by lone individuals and would inhibit rather than encourage the evolution of eusociality.
The major predator of the hypothetical vertebrate would have to be (9) able to enter the burrow but be deterred by the heroic acts of one or a few individuals. This would allow for the evolution of divergent life lengths and reproductive value curves between workers and reproductives. Predators fitting this description would include snakes.
The eusocial vertebrate was also expected to (10) live in the wet-dry tropics because plants there are more likely to produce large roots and tubers that store water and nutrients to help them survive the dry periods. The soil would need to be (11) hard clay because otherwise the nest would not be safe from digging predators. These two characteristics further suggested (12) the open woodland or scrub of Africa.
Alexander described this social vertebrate in a series of guest lectures at North Carolina State University, University of Kansas, University of Texas, Colorado State University, Arizona State University, University of Arizona, and Northern Arizona University at Flagstaff in 1975 and 1976. At Flagstaff, mammalogist Terry Vaughan suggested to Alexander that his hypothetical eusocial rodent was a "perfect description" of the naked mole-rat Heterocephalus glaber. He further described the burrowing East African mammal and suggested that Alexander contact Jennifer Jarvis, an authority on African mole-rats. Jarvis had studied the ecology and physiology of naked mole-rats but at that time nothing was known about their social system. Subsequent field and laboratory observations have confirmed that they are in fact eusocial, as Alexander's model had predicted, and that the other elements of his model are accurate as well (Braude and Lacey 1992; Jarvis 1981; Sherman and others 1991; Sherman and others 1992). This case demonstrates one type of predictive power in modern evolutionary theory.
Evolutionary biologists are making new discoveries every day. To suggest that evolutionary biology is either untestable or unpredictive ignores their vast body of work including the dramatic discovery of eusociality in the naked mole-rat based on clear understanding of the selective forces leading to the evolution of social behavior.
Many thanks to Nancy Berg, Keith Butler and two anonymous reviewers for their valuable comments and suggestions.
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This textbook discusses evolution, a controversial theory some scientists present as a scientific explanation for the origin of living things, such as plants, animals and humans. No one was present when life first appeared on earth, therefore, any statement about life's origins should be considered as theory, not fact.
No teacher or administrator in a local education agency shall teach the theory of evolution except as a scientific theory. Any teacher or administrator teaching such theory as fact commits insubordination. (Tennessee HB 2972/SB 3229 1996).
As part of any science curriculum wherein students are taught concerning the origins of life and living things, including the origins of humankind, teachers shall have the right to present and critique any and all scientific theories about such origins and all facets thereof, including without limitation scientific theories other than evolutionism.
Whenever a theory of the origin of humans or other living things that might commonly be referred to as "evolution" is included in the instructional program provided by any school district or educational service center, both scientific evidence and related arguments supporting or consistent with the theory and scientific evidence and related arguments problematic for, inconsistent with, or not supporting the theory shall be included.
1) The launch of the Sputnik satellite by the Soviet Union led to a perceived crisis in American education. In turn, the federal government sponsored the writing of biology texts by the Biological Sciences Curriculum Study. These textbooks became widely used in the seventies and, for the first time, placed strong emphasis on evolution as the basis of modem biology. This created a fundamentalist backlash by the 80s.
2) Fundamentalists were apparently converted from the Day-age and Gap "theories" because the Bible could be interpreted more literally. It was no longer necessary to assume that "day" meant a long time or that the Bible had a major "gap" in its historical account. It was particularly attractive to pre-millenialists who took the entire book literally. Flood geology had now also lost its negative association with the Seventh Day Adventists. Instead, it appeared to give scientific respectability to fundamentalist beliefs about creation.
If you are an evolutionist, you are not a theist in the sense that your theism has anything to do with the real world. Your belief about the real world is evolution, and that means time and chance. If you believe that God has something to do with the real world, then you can't be an evolutionist because evolution is run by chance, not by God, by definition.Koukl holds that evolution and Christianity are in direct opposition to one another. This is a common, perhaps even universal, position among those at the forefront of this movement as well as among those listening to them. This view has become the linch-pin of the log jam that is preventing honest discussion of the science of evolution (that's not a mixed metaphor, but a compound metaphor). As a committed, thoughtful and sincere Christian, Koukl says that the most important thing in life is his relationship with God. If accepting the reality of evolution means abandoning that relationship with God, no conceivable scientific evidence will move him. That is understandable, even expected. Before we can hope to make progress with Koukl and his numerous allies, we must address the compatibility of their profoundly held religious beliefs with the idea of biological evolution. This is where it gets dicey. We should be arguing evidence. Evolution is a scientific theory, not a philosophy. But that is pointless until we get past this philosophical/religious question.
Science has limited its area of study to the area of natural occurrences. Not only has it limited its search to that area, but it has essentially said that that is the only area that really exits.... If only nature exists, then it turns out that we are merely parts of the machinery in the workings of nature, and we are the unwitting victims of the machinery of cause and effect happening over time without any plan. That robs human beings of their dignity. Clearly, if we are the product of chance, then we have no purpose.... We are all unwanted pregnancies.... Mother nature didn't want us... It just spewed us forth. It just unconsciously squeezed us out. We were the thoughtless conceptus of intercourse of blind natural compulsions with no thought given to us, strangers who accidentally bump into each other in the dark of the universe. We are bastards of the one-night stand if evolution is true.You cannot dispute that passion by pointing to the postdentary bones of a therapsid reptile and saying, "Look. A transitional form!" If, however, it were possible to convince Koukl and his colleagues that evolution need not threaten their world view, the rest of the conflict would largely evaporate.
Since the mid 1980s, scientists have compared mitochondrial DNA (mtDNA) from several different humans, reconstructing an ancestor of living human mitochondria about 100-200 thousand years ago, which probably lived in Africa (Cann, Stoneking and Wilson 1987). More recently, other researchers reported similar results from a study of human Y-chromosome DNA indicating a common ancestor of a large part of the human Y-chromosome at a similar or more recent time, also in Africa (Hammer, 1995; Hammer, Spurdle and others 1997; Gibbons, 1997). The studies of mtDNA immediately evoked the image of an African "Eve", and now, the Y-chromosome research has evoked a corresponding image of an African "Adam". The metaphorical association between genetic research and the Book of Genesis may have helped sell newspapers, but this metaphor involves a misunderstanding of the meaning of these findings. In both the popular press and scientific journals we see such statements as "All women/men can trace their ancestry back to a single female/male living in Africa X thousands of years ago." Such statements are misleading, and may obscure more interesting aspects of this important research (see side bar1).
The genetic code includes units of information that are kept whole when they pass from generation to generation. Genes are passed on as whole units. The DNA in our mitochondria (cell organelles responsible for energy production) are also passed on as whole units, and a large part of the Y-chromosome is, similarly, passed on as a whole unit. Any stretch of genetic code so inherited necessarily has a single common ancestor — called a "coalescence point" — that existed in a particular individual. Furthermore, each of these units of DNA can, and probably does, have a different coalescence point. So, if there is a mitochondrial Eve and a Y-chromosome Adam, there is also a hair color Medusa and a melanin Midas.
Even if the historical role of Adam and Eve is overstated, there is still reason for excitement about the mtDNA and Y-chromosome studies. These bits of DNA are passed on in humans through only one parent. Mitochondria replicate asexually within cells. The ovum produced by a woman includes a small number of her mitochondria, which in turn reproduce to supply the mitochondria in all of the cells in her offspring's body. The non-recombining part of the Y-chromosome does not swap genetic material with the X-chromosome to which it is matched, so each human male gets all of these genes from his father. Therefore, it is possible to study genetic echoes that reflect different population histories for humans as a whole, females as a group, and males as a group.
Were we gibbons, who do not migrate far and who are very strictly monogamous, this would be less interesting; our mtDNA, non-recombinant Y, and other genes would show a similar pattern. However, humans are diverse and imaginative in their marriage and mating practices. At the very least, we practice serial monogamy. Polygyny happens. Hypergamy (unidirectional exchange of mates of one sex across a cultural boundary such as class), polyandry, and other varieties of marriage and mating practice are widespread in humans now and in the past. Often, males and females differ in their patterns of residence after marriage (commonly, newlyweds move to a residence near the male's family). These factors shape separate histories for maternal and paternal lineages.
Coalescence is key to understanding this, so let's examine this concept more closely. Coalescence is a property of divergent systems, like genes, rumors, and chain letters. Chain letters come in different flavors — some asking for money, others merely warning of bad luck. For each "species" of chain letter, there is a source to which all copies could be traced. As the letter is duplicated and passed from one person to others, it may be changed by accident or design, so over time there are many minor variants of the first document. A hard-working detective seeking the original version of a chain letter could work backwards through postal records to track down the very first copy written months, years, or decades earlier. A lazy detective might simply examine all of the available chain letters and reconstruct a document that must look much like the original (even if not exactly). Our lazy detective might even take a guess as to how many "generations" have passed since the initial letter was written, by noting the number of typos and alterations, assuming that more changes means more generations. In both cases, the first copy of that chain letter is a "coalescence" point. Our diligent detective has located the actual coalescence point, and our lazy detective has estimated or reconstructed it.
To reconstruct genetic coalescence points, scientists use the techniques of our lazy detective, not because they are lazy, but because genetic coalescence points are generally ancient and must be inferred from modern samples. "Mitochondrial Eve" and "Y-chromosome Adam" are not individuals, but estimates of coalescence points based on modern samples. New data added to the equation could move Adam or Eve (independently) back through time, or even to a new region of the earth.
Mathematical modeling of Y-chromosome and mtDNA data has revealed one or more "bottlenecks" in human population history. These bottlenecks are periods when our ancestors were reduced in number and confined to one or a few groups. Bottlenecks are detectable because they reduce the diversity of genetic material. We should not be surprised that our species has passed through these bottlenecks. Repeated severe "Ice Ages" of the last million years or so reduced the geographical range of many animals and plants, causing many species to go extinct (from the point of view of extinction, a bottleneck is a "near miss"). Eventually, genetic bottlenecks may be matched to these climate changes and to archaeological evidence from those times.
The bottleneck model for human history has led to further confusion about genetic Adam and Eve. Evolutionary change such as the rise of a new species is perhaps more likely when a population is broken up into small, isolated groups. Thus, a bottleneck is a good place to look for a speciation event. Also, the earliest modern Homo sapiens fossils date to about the same time as the mtDNA bottleneck. This has led to the idea that the genetic echo from this bottleneck marks the origin of modern H. sapiens.
It is important to remember, though, that coalescence points occur for all genetic units, whether there was a bottleneck or not, or a speciation event or not. The identification for a coalescence point is an inevitable outcome of comparing variants of a gene. Perhaps coalescence points will be found to cluster in time near important evolutionary events, but for now there is no evidence that this is the case. Perhaps the life and times of genetic Eve, Adam, Medusa and Midas were quit ordinary.
Not all bottlenecks are genetic; some are informational. The most recent Y-chromosome results are very interesting, and clearly deserving of news coverage. But there have been several studies of human Y-chromosome variability going back several years which have not been as widely reported (see Gibbons and Dorozynski 1991; Shreeve 1991). Low variability in Y-chromosome DNA has been found in several populations. There is a Jewish Adam (Lucotte and David 1992; Lucotte, Smets and Ruffie 1993), a Finnish Adam (Sajantila, Salem and others 1996), and a Native American Adam (Karafet, Zegura and others 1997), for instance. If the geneticists have it right, and this variability is properly calibrated (the Y-chromosome is a badly behaved genetic mess, perhaps not surprisingly), then it would appear that male population histories have more restrictions than do female histories. This accords with what we know about human reproductive patterns. Males vary more than females in their reproductive output. Some males have far more offspring than others, and many males have no offspring. Each female is likely to have a nearer to average number of offspring. This would cause apparent bottlenecks in the male lineage that would not appear in female-only DNA.
Stay tuned. Fifteen years ago, when this sort of research was just getting off the ground, it was difficult, time-consuming and expensive to analyze genetic data. The first studies of mtDNA required human placentas, which are not easy to come by. Now, geneticists extract, isolate, and sequence DNA from many different tissues, more cheaply and more quickly. Until recently, geneticists had all but given up on the Y-chromosome, which appeared to be poorly behaved as a genetic clock. Now somewhat redeemed, the Y-chromosome is starting to yield promising results. Although earlier work in human historical genetics was important, it is also true that the data are only now starting to roll in, and the next few years should be a very exciting time.
In the beginning was the word (on Adam and Eve)
The following quotes are reproduced here to demonstrate a range of conceptions about mitochondrial and Y-chromosome historical genetics. They are taken from articles in the popular press, scientific journals, and web sites. The author has chosen to not provide citations for these phrases, in order to avoid pointing fingers at well meaning writers, and because many of these quotes are subtitles or pullouts that are probably the work of anonymous editors.
This source goes on to clarify (sort of)...
One source reports that
To be fair, this source later adds:
Better. But the redemption is quickly mitigated by this follow-up:
A prestigious scientific journal reports that
Gibbons A, Dorozynski A. Looking for the father of us all: After finding the controversial "mitochondrial Eve," molecular biologists are hoping that the Y chromosome will lead them to the genetic Adam. Science 1991; 251(4992): 378-80.
Gibbons A. Y chromosome shows that Adam was an African. Science 1997; 278(5339): 804-5.
Hammer MF, Spurdle AB, Karafet T, Bonner MR, Wood ET, Novelletto A, Malaspina P, Mitchell RJ, Horai S, Jenkins T, Zegura SL. The geographic distribution of human Y chromosome variation. Genetics 1997; 145(3): 787-95.
Hammer MF. A recent common ancestry for human Y chromosomes. Nature 1995; 378(6555): 376-9
Karafet T, Zegura SL, Vuturo-Brady J, Posukh O, Osipova L, Wiebe V, Romero F, Long JC, Harihar S, Jin F, Dashnyam B, Gerelsaikhan T, Omoto K, Hammer MF. Y chromosome markers and trans-Bering Strait dispersals. American Journal of Physical Anthropology 1997; 102(3): 301-16.
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Sajantila A, Salem A, Savolainen P, Bauer K, Gierig C, Paabo S. Paternal and maternal DNA lineages reveal a bottleneck in the founding of Finnish population. Proceedings of the National Academy of Sciences of the United States 1996; (93)21: 12035-40.
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