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.

Academic Extinction
More and More, Evolutionary Theory is Becoming Nothing More than Darwinian Mantra

BY David Berlinski
Friday, April 1, 2005
Wearing pink tasseled slippers and conical hats covered in polka dots, Darwinian biologists are persuaded that a plot is afoot to make them look silly. At Internet web sites such as The Panda's Thumb or Talk Reason, where various eminences repair to assure one another that all is well, it is considered clever beyond measure to attack critics of Darwin's theory such as William Dembski by misspelling his name as William Dumbski.

Publishing his work with the Cambridge University Press, hardly a venue known for its slack intellectual standards, Dembski has proposed that designed structures in nature might be detected by means of a rigorous analytical test. The idea of design is a staple of the social, anthropological and forensic sciences. It is the crucial metaphor in Noam Chomsky's minimalist theory. Dembski holds two PhD's, the first from the University of Chicago in mathematics, and the second from the University of Illinois in philosophy.

Dumbski indeed. Elsewhere, rhetoric is more measured, even if it conveys arguments no more compelling. After alluding to Intelligent Design at a faculty cocktail party—Je m'imagine cela—the dean of undergraduate education at the University of Calfornia at Berkeley was amazed and remarked “that colleagues indicated a great deal of sympathy for this alternative to ‘Darwinism.’”

His amazement notwithstanding, the dean's defense was a model of evasive circumspection.

“Although I told them that few, if any, reputable biologists in the country subscribe to intelligent design, I could tell that they were not persuaded. Somewhat dismayed, I turned to other, more congenial issues.”

Now these are remarkable words, if only because they reveal that a prominent academic regards it as quite natural to be dismayed on those occasions when his views are disputed. They are remarkable as well because they indicate that the dean is persuaded that dissent might in the case of Darwin's theory be ended by an appeal to what “reputable biologists believe.”

My dear dean. Allow me to set you straight. It is precisely the reputable biologists who are under attack. For the first time, they are being asked to defend the thesis that biological design is more apparent rather than real. The effort has left them breathless. They are, of course, not about to surrender their ideological allegiances. Their rhetoric fills the op-ed columns of every liberal newspaper and is conveyed additionally by academic allies whose welfare is contingent on theirs —analytic philosophers, pop psychologists, and even newspaper columnists eager beyond measure to do anything but attentively study the evidence.

But what is at issue, of course, is not what reputable biologists believe, but whether it is true.

A great many ordinary men and women are persuaded that it is not. And even at Berkeley. Their dissatisfaction has traveled as far a field as Paris. Expertise is hardly at issue. Darwin's theory of evolution is not protected by the twelve doors mentioned in Revelation 21:21. It is right there in plain sight.

The unfathomable complexity of living systems, Darwin's theory affirms, is the result of random variation and natural selection. Is it indeed? Of these concepts, the second is hopelessly confused and the first is of no intellectual interest. Darwin's theory, when the thing is plainly considered, is no more than a form of behaviorism written on the level of the species. Like those endless psychological experiments, all of them conducted apparently at Harvard, in which some undergraduates were trained to say ouch after being stuck with a pin, and others to say ooh, species, on Darwin's view, are trained to say ouch or ooh when stuck by the environment.

B.F. Skinner is long dead, and among the dinosaurs, behaviorism in psychology has been the first to descend, honking sadly, into the tar pits.

What reputable biologists believe is one thing; what they fear is there in plain sight.

“Everyone on the Berkeley campus should be exposed to the arguments supporting real science and to the fallacies of views based on guesswork and unfounded hypotheses.”

Ah, yes, Everyone should. Even at Berkeley.

David Berlinski

What scriptural passages? There are none to be considered. Again, you cant interpret something that isnt there. You guys are too used to positing missing links and jumping to erronous conclusions.

Dear, dear, dear. We were discussing Gen 9:22-27, which I posted back in 1116:

And Ham, the father of Canaan, saw the nakedness of his father, and told his two brethren without. And Shem and Japheth took a garment, and laid [it] upon both their shoulders, and went backward, and covered the nakedness of their father; and their faces [were] backward, and they saw not their father's nakedness. And Noah awoke from his wine, and knew what his younger son had done unto him. And he said, Cursed [be] Canaan; a servant of servants shall he be unto his brethren. And he said, Blessed [be] the LORD God of Shem; and Canaan shall be his servant. God shall enlarge Japheth, and he shall dwell in the tents of Shem; and Canaan shall be his servant. [Gen 9:22-27]

I've heard of short attention spans, before, but ...

I argue against folks taking the first dozen or so chapters of Genesis literally because it leads to people thinking one race is superior to another.

Consider your stated reasoning. You reject something as truth because some people may misuse it? If something is true, it is true even if some people ignore other truths that would give it context, leading to misapplication.

Fortunately you have millions of examples of Christians who accept the first several chapters of Genesis mostly literally who also are against any racism. These same people go ahead and read the rest of the Bible and this leaves no room for a view that makes God a respecter of persons.

The Bible says all men are of the same blood, literally. That is why you have to read the entire Bible, not just a piece of it.

I suspect your stated reason is not the real reason you have a problem with the first several chapters of Genesis, but any premise to undermine them will do.

Your non-literal interpretation of this Bible story is what? I would like to hear what you have come up with.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.