Teaching Darwin

Teaching Darwin Why we're still fighting about biology textbook. by Paul McHugh 03/28/2005, Volume 010, Issue 26

EIGHTY YEARS AGO THIS SUMMER, the Scopes trial upheld the effort of the state of Tennessee to exclude the teaching of Darwinian evolution from Tennessee classrooms. The state claimed Darwinism contradicted orthodox religion. But times change, and recently a federal judge ruled that a three-sentence sticker stating that "evolution is a theory not a fact" must be removed from Georgia high school biology texts because it contradicts orthodox science and represents an unconstitutional endorsement of religion. Both legal mandates--no Darwin yesterday, nothing but Darwin today--look less like science than exercises in thought control.

Everyone agrees that the Scopes trial (viciously caricatured in the play and movie Inherit the Wind) was a setback for the teaching of scientific reasoning. But the same is true of the Georgia ruling, Darwinism being quite obviously a biological theory and open to dispute. To claim otherwise is to be woefully misinformed.

Science, as high school students need to know, is a logically articulated structure of beliefs about nature that are justified by methods of reasoning one can evaluate. It is whether the methods pass muster that counts for or against a scientific opinion, not how the opinion fits our preconceptions.

Charles Darwin proposed that random variation within life forms, working together with natural selection ("the preservation of favorable variations and the rejection of injurious variations") across the vast expanse of time since the earth was formed, explains "how the universe created intelligence," as Francis Bacon had stated the problem a few centuries before. To judge whether the matter is now closed to all criticism, such that Darwinism stands with scientific facts like "the earth is a planet of the sun" or "the blood circulates in the body," demands we consider Darwin's method of reasoning.

Evolutionary biology, in contrast with physics and chemistry, is a historical science--the evolutionist attempts to explain events and processes that have already taken place. Laws and experiments are inappropriate techniques for the explication of such events and processes. Instead one constructs a historical narrative, consisting of a tentative reconstruction of the particular scenario that led to the events one is trying to explain.

Darwin, Mayr goes on, "established a philosophy of biology . . . by showing that theories in evolutionary biology are based on concepts rather than laws."

After noting Mayr's fearless use of the words "tentative," "philosophy," and "theory," one surely is justified in responding: No wonder Darwinism, in contrast to other scientific theories, seems an argument without end! It's history--indeed, history captured by that creative-writing-class concept narrative. If historical narrative--and the "philosophy" it propounds--are what justify the Darwinian opinions, the textbook writers of Georgia can legitimately claim that Darwin's "tentative reconstruction" is not only a theory but a special kind of theory, one lacking the telling and persuasive power that theories built on hypothesis-generated experiment and public prediction can garner.

DARWIN HIMSELF UNDERSTOOD that questions raised about his narrative had substance. In Chapter IX of On the Origin of Species, he noted that the fossil record had failed to "reveal any . . . finely graduated organic chain" linking, as he proposed, existing species to predecessors. He called the record "imperfect" and went so far as to say, "This, perhaps, is the most obvious and gravest objection which can be urged against my theory." Darwin presumed that the problem rested on the "poorness of our palaeontological collections" and would be answered when more of "the surface of the earth has been geologically explored."

In the same Chapter IX, Darwin also acknowledged that the fossil record does suggest the "sudden appearance of whole groups of allied species all at once." He noted that if this fact were to stand, and "numerous species belonging to the same genera or families have really started into life all at once, . . . [it] would be fatal to the theory of descent with slow modification through natural selection." He forestalled that fatal blow to his theory by asking his readers not to "over-rate the perfection of the geological record."

Any sympathetic reader of Darwin's history would readily allow him the point--that earlier life forms might have all come and gone elsewhere than where later forms emerged and might have done so without leaving a fossil record to demonstrate the smooth gradation between species. But such a reader should admit, as Darwin did, that the absence of the record is a serious matter--especially when it persists to this day, nearly a century and a half after Darwin's book was published. This imperfection of the historical record was, after all, sufficiently embarrassing to provoke some evolutionary biologists nearly 100 years ago to try to improve on the record by manufacturing the counterfeit fossil Piltdown Man.

Even among committed Darwinists, the imperfection of the fossil record has been a source of huge argument. The Darwinian fundamentalist Richard Dawkins of Oxford believes in smooth and gradual evolutionary processes. He became a vicious antagonist to Stephen Jay Gould of Harvard, who championed "punctuated equilibrium," with abrupt species generation after millennia of stability. Dawkins attacked Gould in large part because Gould's idea greatly shortened the time evolutionary processes had to generate species.

All the more reason, then, for our sympathetic reader to look for other means of supporting Darwin's narrative. Perhaps the demonstrable variations that occur in species living under altered circumstances might answer objections.

With this in mind, Darwin devotes the very first chapter of On the Origin of Species to describing variations in plants and domestic animals produced over time by methodical selective breeding by farmers and fanciers. Plainly their practice of permitting only the most choice individuals to reproduce and so "enhance the breed" demonstrates how hereditary modification of members of a given species is possible--indeed, it displays the process.

Darwin, however, then makes an extrapolation. Beginning with the reasonable presumption that the hereditary mechanisms involved in producing these enhancements in the barnyard must be available and randomly active in nature, he proposes that from such random variation can spring new species. Variation--repeated ad infinitum down the ages, with its products culled by natural selection rather than by artful human breeding--is the process by which Darwin links up all of biologic creation. This is the Darwinian narrative in its clearest form--history by extrapolation--and it is not problem-free.

MANY OF US were taught these Darwinian extrapolatory links to the evolutionary narrative in high school, usually with photographs of the European peppered moth (Biston betularia), which became darker with environmental pollution and thus less conspicuous to bird predators in industrial areas. The same idea springs up in discussions of the development of bacterial resistance to antibiotics, or of the transformation of the beaks of finches under the pressure of drought. We were taught in high school that these observable biologic changes display evolution "in front of your eyes."

But not everyone agreed with this conclusion. Many criticized the Darwinists for extrapolating too far, and now the Darwinists confess that actual, observable variation--whether in the barnyard or in nature--demonstrates only the capacity of a species population to vary within limits. The original species picture reappears when either the farmer's selective enterprise or the natural environmental pressure on the species population stops and crossbreeding recurs. The finches' beaks never turn into pelican pouches but revert to their original shape when the rains arrive.

No farmer or experimental scientist has ever produced a new species by cultivating variations. The peppered moth didn't become a butterfly, and the closely and repeatedly studied fruit fly, despite gazillions of generations producing varieties in the laboratory, always remains a fruit fly. Again, Darwin himself was more honest than his followers have been. He knew the distinction between variations that could be observed and those posited according to the theoretical extrapolation that was key to his narrative. For this reason he repeatedly notes, as in Chapter IV of On the Origin of Species, that "natural selection will always act very slowly, often only at long intervals of time, and generally on only a few of the inhabitants." In this way he puts the process of species generation outside the reach of experimental demonstration.

At this point, the sympathetic reader eager to secure Darwin's narrative might resort to searching the "biochemical record." Surely the molecular structures of DNA, RNA, and proteins contain the long-sought evidence. Again, though, molecular biology helps in some ways in that it shows commonalities across species--just as other aspects of anatomical structures show commonalities--but again it's the distinctions--and the means by which they are generated--rather than the similarities that must be explained to support the theory.

If one turns to DNA to show how Homo sapiens gradually emerged by small and random variations from predecessors, one faces an immediate problem. At the level of DNA, humans and chimpanzees differ by a mere 1 percent, yet the chimpanzee is not 99 percent human in body, brain, or mental faculties--far from it. We need something more than the DNA record to support a narrative linking chimps and men.

Perhaps it's enough for the friendly guardian of the Darwinian narrative to propose that the genes that control the switching on and off of other genes simply changed in some random way, allowing humans to branch off the primate line. And maybe they did. But again, notice, this is a molecular narrative, not a proposition demonstrable by experiment. It's a story that fits the facts--but so might another.

SURELY AT THIS POINT the friendly reader might agree that, like any historical account, the Darwinian narrative can fairly be challenged--not to say that it must be wrong, only that it needs more supportive evidence. Perhaps there are statistical proofs or engineering concepts that could be found, or something else that might emerge that would be subject to verification by the scientific method.

But our would-be friend to evolution will soon discover that any questioning of the Darwinian narrative, no matter how sympathetic, is shouted down. If mathematicians try to say that even with the immense span of geological time available for random genetic variations to act, there is not time enough to produce the human eye, the response--typical for historians, who routinely argue backward from observations to their causes--is, Since the eye exists the math must be wrong.

If Michael J. Behe, the cellular biochemist who wrote Darwin's Black Box, proposes that the complicated molecular mechanisms sustaining the integrity of the cell seem impossible to explain as the result of random variations, the president of the National Academy of Sciences counters by pronouncing, "Modern scientific views of the molecular organization of life are entirely consistent with spontaneous variation and natural selection driving a powerful evolutionary process." That is, he affirms the Darwinian narrative by restating it, not by offering compelling proof that it is true. Lots of views are consistent with the cell's complexity--including the view Behe explores, that an intelligent creator designed the cell to work. But cellular formation needs identified generative mechanisms, not simply a consistent narrative, to explain it--a problem both for those who call on Darwin and those who call on an "intelligent designer."

Official science is too much at ease with the Darwinian narrative--primarily because it can't come up with anything better. As a result, many scientists are driven by an ideological bias and by fear--the thought that any challenge to the narrative will plunge the republic back into some dark age. Richard Dawkins and his associate Niall Shanks predict that, as Shanks wrote, "discriminatory, conservative Christian values [will be imposed] on our educational, legal, social and political institutions" should the public schools permit any airing of questions about the Darwinian narrative. This fear is way over the top, but it's of long standing, and in the past has provoked some loss of judgment among scientists.

When the most distinguished biological scientist of the 20th century, Francis Crick, saw the same complications as Michael Behe, he also concluded that time on Earth and random variation were not adequate to produce the viable cell. Crick resolved the dilemma, in a fascinating book called Life Itself published in 1981, by suggesting that living cells arrived on an unmanned spaceship from another planet, perhaps sent by intelligent beings facing extinction. He called his concept "directed panspermia," and this strange concept (I prefer to call it "life from Krypton") received a respectful hearing from biologists. With this imaginative device Crick could keep the narrative alive. He explained life's cellular origins without worrying about time, kept the God he hated out of the picture, and preserved the possibility of random variation and natural selection working their magic from these "seedlings" from a "galaxy far far away."

BY NOW, it would seem that a sympathetic reader of Darwin, if honest, could conclude the following. Darwinism is an imperfect theory, based as it is on a historical narrative, and carrying as it does the remarkable capacity to explain anything and exclude nothing. It has great strengths, and it has great evidential lacunae that seem no closer to resolution than when Darwin himself called attention to them 146 years ago.

The biological evidence--life rests on the cellular organization of nucleotides and proteins--compels the conclusion that all the various forms of life on Earth derive from a common source, as Darwin emphasized. Life is not recreated with every new species--this is now undeniable. The Darwinian concept of descent with modification seems the most plausible way to relate life and its varieties. Modifications within species are often responses to environmental challenges, and they sustain a species with the variety of expressions necessary for it to survive these challenges.

But when one tries to grasp how the distinct species, as against varieties, are generated--by what mechanism they separate--a pause to reflect is warranted. Darwin's random variation and natural selection may well offer the best available narrative, the most compelling theory. Yet something seems missing--for example, any sense of what propels life's forms toward a progressive complexity, rather than toward a simplicity of design that would guarantee survival come what may.

The discipline of evolutionary biology today resembles astrophysics when Galileo was attempting to explain the planetary orbits and the oceanic tides but lacked the concept of the force of gravity. His observations were accurate enough, but explanations awaited an Isaac Newton.

Evolutionary biology awaits its Newton. And until such a thinker emerges--to provide a fuller conception of the history of life and especially the forces at play that explain how things happened as they did--those who would expel all challenges to the Darwinian narrative from the high school classroom are false to their mission of teaching the scientific method.

Scientists as they engage in dialogue with others should abhor attempts to close off the conversation by excessive claims for any privileged access to truth. Scientists should tell what they actually know and how they know it, as distinct from what they believe and are trying to advance. If all of us, scientists and non-scientists alike, accepted that guiding principle, the 80-year history of attempts to use law to stifle the teaching of science--stretching as it does from the courtrooms of Dayton, Tennessee, to those of Cobb County, Georgia--could perhaps finally be brought to a close.

Paul McHugh is a university distinguished service professor of psychiatry and behavioral science at the Johns Hopkins School of Medicine and former psychiatrist in chief of the Johns Hopkins Hospital.

Like I thought. You have no time at all for the bible. You think it is just a product of human imagination. I suspect you don't believe in God at all. This defines your world view and therefore your theory of origin. Your world view defines your science, not the other way around.

Gee, and you're the one who claimed to have taught science. My God, no wonder our kids are behind the rest of the world.

5 : a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena

The problem is with ALL our science teaching. We give students the arrogant belief that we have some real understanding of things and we do it in a way that does not call them to question the 'powers that be' (in this case, the all holy scientist). Liberals love this because then they can tell people all kinds of stuff about things like global warming and as long as they claim it is from 'scientists' then it is believed.

Seriously, where did you go to school? We are the same age yet you must have had a vastly different education experience than I (not in the condescending way). I don't think you quite understand the process of science. Scientist do not simply do some research, publish it, and assert its truth. All research must undergo a peer review process in which data must be validated. I don't know where you see all this scientist arrogance. Questioning your "powers that be" is the very essence of the scientific method!!!

It is possible to excerpt text without misrepresenting the author, but in this case the excerpted quote misrepresents the author's intentions.

Ah, but can you always distinguish between the two? For example:

"Verily I say unto you ... it came to pass that ... both the daughters of Lot were with child by their father ... go and do thou likewise."

As you can see, it is possible to learn debate tactics from the creationists.

Well I know biologists (who are also recent grads) that would disagree with that. You will have to forgive me if I believe them over a stranger. I have enough knowledge of their powers of bias detection to trust the assessment. Everyone has biases, some just hide it better than others. The closer someones beliefs are to your own the harder it is to detect bias.

ah, but are they discussing evolution?

or just laying bait to cause controversy with religious people who dont like seeing their beliefs and their values attacked and ridiculed?

You're supposed to put a space between a word and a following parethesis.

You know, the reason I'm nit picking is because it is my contention that sloppy writing bespeaks sloppy thinking. That you couldn't be bothered to look up the spelling of a word (or to even use a handy spellchecker) or to learn how to use a punctuation mark correctly means, to me, that you can't be bothered to double check any claims you make or to research any particular point.

Must high school science teachers are not qualified in that regard either. They teach what is in the book. Most conservative can agree public school text books have a heavy liberal bias. All things considered I think it is very important that students look at what is in those books with and open mind. In case you forgot, that is ALL that sticker said. I fail to understand anyone can argue AGAINST warning students that a science book is not all fact unless they have an agenda. To argue against including THAT sticker as written indicates and agenda to teach all students that evolution is a FACT and is never to be doubted.

Well then, that sticker has to go on all science text books, right? Oh, and to be fair, athiest groups should be allowed to insist on a warning sticker regarding the unsubstantiated claims in the bible, at any public function where bibles are present, right?

Ok.

My question to you is; considering the Biblical text I posted to you, can you understand why I would take the position I have taken?

P.S. The Biblical narrative falls under the evidenciary realm of provability one might find in a courtroom. If this method of examination is not valid, we have greater problems than debating origins. Similarly to Evolutionary Theory, archaeologically "scientific" data has been collected to reinforce Biblical accuracy. This in my opinion puts these two fields of study in the same category for provability, as opposed to something that can be experimentally proven in a lab [Knowing about early life, being highly circumstantial evidence for it's lack of observers (other than God of course)].

Truth always comes down to accurately understanding information. The closer to first hand observation we have to the data, the more convinced we become.

Funny, I thought it was to be continually reminded that arrogance and belittlement are always with us.

Really????

Consider the post #183 by anguish.

I happen to be a Christian and a scientist, and I really resent the notion that to be a scientist is to be anti-God. Most of my friends at work are also scientists and Christians. None of us see a contradiction.

Indeed, I have argued that the Creationism / ID viewpoint is anti-God. I will repeat the argument here:

When you two go to heaven, and I will stipulate that you might be good people and make it, God will say to you: "Well, TalonDJ and anguish, you are good people. Welcome to Heaven. But that Creationism stuff. Did you really think that was the best I could do??? And that ID stuff was positively insulting!!"

Hello Mr. Mayor. I am one of your three beasts, remember? (chuckle - I will laugh all the way to the end over that).

Scientists are required to understand many things outside of science, in other words to be complete humans. It is part of the curriculum. Unfortunately non-scientists are rarely required to understand science; it may give them headaches.

As examples, I give any of the CREVO threads, and your comments in them, especially.

Talon, all I ask is that you provide some examples of bias. Are professors who present evidence behind widely accepted theories biased? Is a professor who is teaching molecular structure and DNA biased? The professor isn't providing alternative theories? While its impossible to remove all bias from anything, the only bias these professors hold to a bias toward scientific validity. Now don't get me wrong I am sure there are plenty of bad professors who over-steps their bounds but I think you are making some gross over-generalizations.

hello beast. Well perhaps we can discuss veterinary science, after all, perhaps I know more than anyone else here about that. what is your current medical condition, exactly, is it that you are cryptorchid?

That's pretty much the definition of a quote out of contxt.

No it isn't. A quote out of context changes meaning. "I don't like raisins.... " is out of context when the context is "I don't like raisins from Del Monte as much as those from Dole."

The author's intentions were clear. He was skeptical of certain evidence and it wasn't evidence from creationists.

Irrefutable data? You feel that quoting the Bible is irrefutable data?

You are aware that I said, "I presented irrefutable Biblical data that God created Adam and Eve as mature adults."

Clearly I was arguing that from a Biblical standpoint, God created man and woman in a mature state, already being male and female. This refutes the idea that God used evolution as a creative method.

The Bible is nothing more than an allegorical text. A work of fiction. An attempt to pass on a specific culture's morals and parables.

You realize that by this statement you are discounting the intelligence of the brightest minds in history. You may wish to reconsider, but considering you were created by a God who gave you the freedom to commit or reject, do as you wish.

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