Kitzmiller v Dover Area School District, in which judgment was pronounced on 20th December 2005, is the court case that established that Intelligent Design is not science, but a form of religiously motivated creationism, and as such may not be taught in publicly funded schools in the US. This is a shortened version of what I told the students at Texas Academy of Mathematics and Science, University of North Texas’s early admissions programme, whom I was privileged to be teaching at the time of the trial. I have omitted my discussion of the embarrassing Intelligent Design pseudotext, Of Pandas and People, and the even more embarrassing statement that the Dover School Board instructed teachers to read, for reasons of space and because I have discussed them here before. I have tried to avoid rewriting in the light of what I have learnt since, but insert some comments for clarity, and links where relevant.
But what is really extraordinary about this presentation is, that it is necessary at all. Having been a hundred years in the making, the central notions of evolutionary biology erupted into public awareness a century and a half ago, and, over the following 50 years, the major religious groups of the industrialised world came to terms with these ideas. The creationist challenge to what has been, for over a century, the central theoretical framework of biology, is a recent development, and, very specifically, a 20th-century American phenomenon. Very recently, creationism has changed its name to Intelligent Design Theory, but this is a purely cosmetic change.
I expect that this talk will please no one. I will, as you might expect, argue against Intelligent Design arguments. Indeed, I will go much further, claiming that such arguments are part of a particular kind of mindset, which I will call literalism (although some call it fundamentalism), and that the rise of this mindset represents a most serious threat to knowledge.
When a majority of Americans polled reject the central concepts of mainstream modern biological science, something is very badly wrong. I will also argue that the scientific establishment has contributed to this disaster (and when a majority of the American public deny the plain facts of biology, this is a disaster) through its own ineptitude and philosophically muddled teaching. I will argue that literalism is a harking back to a prescientific mode of thought, that is systematically distorts the way in which its practitioners view the world, and that it represents a seriously impoverished approach at the spiritual level and the level of human affairs, as well as being completely hostile to the spirit and practice of science.
The standard picture of modern biology, as I will call it, stems from the work of Linnaeus who in 1737 establish the classification that we still follow into species, genera, et cetera. It was not long before Buffon and others started explaining similarity in terms of family resemblance. A critical stage in this development took place in the mid-19th century, with the idea that species originate through descent with variation, followed by competition between the different variants. We associate this insight with Charles Darwin’s publication of The Origin of Species, but the fact that the same key ideas were independently discovered by Alfred Russel Wallace suggests that this was an idea for which the time was ripe. The entire evolutionary position is still sometimes referred to as “Darwinism”, especially by its opponents, but this is completely unhistorical, and the expression should be reserved for the specific ideas put forward by Darwin, Wallace, Thomas Huxley, and others in the mid-19th century. Current evolutionary theory is a much refined and altered version of this, much as present day atomic theory is a much refined and altered version of that used by mid-19th century chemists.
The immediate upshot of Darwin’s publication was intense debate between those who welcomed it as a major scientific advance, and those who saw it as a threat to established ideas in religion, and in particular to the authority of the Bible. In Europe, and particularly in Britain, the debate was played out in the next few decades, and led to general acceptance by the churches of the correctness of the evolutionist position, and reinterpretation of Genesis in terms of allegory. Darwin himself lies buried in Westminster Abbey.
Since that time, the argument for evolution has enormously strengthened, in ways that Darwin and Wallace could not have foreseen. The work of Grigor Mendel and his successors gave us a science of genetics, which shows how it was possible for variations to be passed on undiluted from one generation to another. We can understand how the necessary variation arises, because we know about mutations, and since the work of Franklin, Crick, and Watson in 1953, we even know the nature of the genetic material. In Darwin’s time, there were massive gaps in the fossil record, so large in fact that Wallace continued to believe that humanity was a separate creation, rather than having common ancestry with the apes. By now, we have a whole range of intermediate forms, so much so that there is held the ongoing debate among anthropologists and paleontologists as to which ones lie on our direct line of ancestry, and which represent evolutionary dead ends. We have the discovery of deep time, necessary for evolution, and the development of about a dozen separate, mutually consistent, methods of radioactive dating, which enable us to assign dates to fossils, going back over 3 billion years. Finally, and most convincingly, we have the development of DNA sequencing, which makes it possible to give a quantitative estimate of how long different species have been developing separately, and the family relationships discovered in this way bear a remarkable closeness to the family resemblances observable when we classify present-day organisms, and to the distances between branches of the evolutionary tree, as displayed by similarity of features and the fossil record.
I was therefore amazed, on arriving in Texas in 1988, to discover that in the minds of many Americans these matters were still in dispute, and since then I have been appalled at the increasing expression, for largely political ends, of the view that evolution is seriously in doubt, and even that creationism should be offered in biology classes in schools.
I fear that the usual reaction of us scientists including myself until recently, has been to ask “How can anyone believe anything so stupid?”, and then not wait for an answer. Or, alternatively, to put forward reasoned defenses of the evolutionist position, as I have spent the past few minutes doing, without stopping to examine the thinking of their opponents. The result is an outpouring of writings by scientists, for scientists, which are either ignored by the creationists, or, worse, mined for phrases that can be used against us. What I plan to do today and henceforth, is to take a rather different approach, to suggest that the opposition to evolutionist biology depends on what I shall call “literalism”, and to contrast the methods of literalism with those of science. I shall argue that literalism extends far beyond the usual biblical context that we associate with the word, that literalists will regard as legitimate kinds of argument which to scientists seem downright dishonest, and that through failure to understand the nature of literalism, we scientists and science educators give ammunition to our enemies. We are losing the public relations battle because we have not taken the trouble to understand what we are up against.
We (and by we, I mean the whole of mainstream science) are at war, and don’t know it. This is why I am urging scientists to play attack, rather than defense. If an adversary who is determined not to be convinced demands more evidence, there is no point in trying to give it to him. He will complain of the inadequacy of any volume of evidence, and will always be able to ask for more, in much the same way that the coal companies keep on demanding more evidence for global warming. For example, if you point the fossil record as evidence, the creationist will point out that there are times in the fossil record, and however detailed the evidence may be that you offer, there will still be gaps. If you fall for this ploy, you will always be on the defensive, and your opponent will always seem to an outsider to have the stronger case. As I shall show later by example, what you should do is to ask the creationist why, in his scheme of things, there is any fossil record at all.
Firstly, let me define my terms. By literalism, I mean the belief that it is possible to find out the truth about things by closely examining words. By creationism, I mean the belief that separate species or groupings represent separate acts of divine intervention. Since there is only one serious candidate for the role of Intelligent Designer, and since proponents of Intelligent Design never give us any details of how the designs come to be embodied, I think we must conclude that is simply a form of creationism that dare not speak its name. By absolutism, I mean the belief that it is possible to arrive at a final absolute statement of the truth. Absolutists generally believe, although logically they do not really have to, that they themselves happen to be the ones in this fortunate position.
We need some terms for the contrary positions. I shall refer to the opinion that all living things on Earth share a common ancestry as the standard picture. I will use the term fallibilists for those who believe that, except perhaps in certain areas of mathematics or of direct experience, absolute certainty is not of this world, that some degree of uncertainty attaches itself to all their opinions, and that they are certainly wrong about many things, although they don’t know which. In their working lives, at least, all scientists are fallibilists. That is because we care about the facts, and our experience shows that the facts can prove us wrong. This position leaves no room in science for absolutism or literalism. Nor should we want there to be, since reality is more interesting, subtle, and complex than our ability to describe it.
I think you can already see how this is going to play out. Scientists will, ideally at least, make carefully qualified statements, judiciously spelling out the degree of uncertainty in their opinions, and emphasising their willingness to change their beliefs in the face of new evidence. That’s because we care about the facts. They will maintain, correctly, that literalist arguments are devoid of scientific merit, and will naïvely imagine that that settles the matter. Literalists will often be absolutists, and will attribute the cautious way in which scientists use words to lack of conviction. The literalist will freely quote the scientist out of context. The scientist will complain that this is dishonest, that his or her meaning is being distorted, but the literalist will reply, in all sincerity, that he cannot be faulted for simply citing what was actually said. If the scientist regards the literalist at this point as dishonest, the literalist will regard the scientist as evasive. The result is that we have a cottage industry based on literalist quotation mining, and a counter-industry in which the defenders of science try to keep up by mending the fractures, and putting the quotations back in context.
All this seems to me a symptom of a deeper problem. The fallibilist will assume that the conversation is in the last resort a cooperative effort, a kind of conversation, with both parties interested in winding up a little bit closer to the truth. The absolutist believes he knows the truth already. For him, the conversation is a competitive debate, where the aim of each party is to vanquish the other. The absolutist will therefore play by rules closer to those of the law court that the laboratory. He knows the truth, and all he has to do is to make the case for it. His job is to assemble all the materials, good, bad, and indifferent, that supports his own case and to trash any counter arguments made by their opponents. Faced with these tactics, scientists will believe themselves to be the victims of conscious intellectual dishonesty, and may even withdraw from the debate.
Literalism has various attractive features, some of which I have already mentioned. There is certainty, provided one can convince oneself that one has interpreted the text correctly. There is power, if you can convince other people of your superior ability to interpret the sacred texts. There is finality, since once something has been said, with sufficient authority, the issue is regarded as settled once and for all. There is a sense of comradeship and shared purpose with those that use the same texts as you do. Some literalists go so far as to believe that everybody who agrees with them will go to heaven, and everyone who disagrees will go to hell. A powerful consideration, which may well distort anyone’s judgment. For American audiences in particular, there is the ever popular illusion of individualism; this is what I believe, dammit, and no pointy head is going to tell me different. Above all, literalism gives you an easy way of resolving complex issues. It deals with words instead of dealing with things. When presented with a thing, the literalist will put it in a box, put a label on the box, and then decide how to deal with the thing by reading the label.
I argued that literalism is intellectually bankrupt in the area of biblical exegesis, quoting 2 Corinthians 3:6: “the letter killeth, but the spirit giveth life” and pointing, much in the spirit of Maimonides, to texts that surely were never meant to be taken literally. My first example was day and night on Day One of Genesis, but no sun and moon until the fourth day.
How could you have alternating day and night before you had sun and moon? I ran this argument by a literalist, with whom I had a long and informative correspondence, and he said, more or less, no problem: God can turn the lights on and off whenever He feels like it. Fair enough, perhaps, but notice that if you argue like that, you cannot pretend to be doing science. By invoking God’s will in this way, you can explain absolutely anything, you can never be proved wrong, and your idea can never be tested against the facts.
The poet John Donne gives, as an example of what humanity does not understand, “Why grass is green, or why our blood is red”. Oddly enough, one of my own first scientific papers helped answer this very question. But using Intelligent Design logic, there is nothing that needs to be explained. Why is grass green, why is blood red? Because the Intelligent Designer so designed it. Why is blood green, why is grass red? Same answer. Intelligent Design theory can explain anything, which means that it explains nothing. It leads to a total end of questioning, since all questions have the same answer. And the death of questioning is the death of science.
I then considered other examples; God being said (Genesis 6:6, I Samuel 15:35) to have changed his mind and repeatedly in Exodus to have hardened Pharaoh’s heart. If you believe in a God who is all-knowing and just, these verses cannot mean what they say. Such arguments, I said, date back to the time of Maimonides, are independent of modern science, and serve to show that biblical literalism is bankrupt on its own terms. I have since discovered the existence of a broad swathe of religious opinion, displayed by Biologos, Evolution Weekend, and the American Scientific Affiliation, who argue in much the same way. I regard the believers in these groups as my natural allies in combating creationism, however much we may differ on other matters.
I said earlier that defenders of the standard picture should stop playing defense, and go on to the attack. It is high time that I did so, and I will proceed by taking Intelligent Design at its word and evaluating it as I would any other scientific theory.
It is difficult to work out what Intelligent Design really means, because its advocates never tell us how it’s supposed to work, but I shall assume that it means that there is a Designer, capable of imposing his design on matter, and that this designer is extremely intelligent. Regarded on its own terms of scientific theory, Intelligent Design theory does make one clear prediction. It predicts that organisms should be intelligently designed. But they’re not.
I stand before you today as living proof of this sad fact. If a freshman engineering student were to turn in my body plan as an assignment, he or she would be gently taken aside by the instructor, and advised to seek some other way of making a living. I sprain my ankle and I twist my knee. I have lower back pain as my disks are squeezed under the weight of my body. My nose gets congested, and my sinuses, with no good way of draining, are a haven for germs. My eyes are back to front, with the blood vessels in front of the retina, getting in the way of the light. I had a dreadful time getting born and millions of children, some of whom I have known, have had an even harder time of it, and ended up permanently brain-damaged.
All of these things are exactly what you’d expect on the standard evolutionary account. We have superposed upright posture on a skeleton originally evolved for walking on four legs. The blood vessels in our eyes trace their ancestry back to the blood vessels of the skin, while the light sensitive cells of the retina are outgrowths of the brain. Over the past few million years, all we simians have been living on our wits, in extremely complex social groups, producing strong evolutionary pressure to enlarge our brains, and in our species in particular this will have been intensified by the ability to make more complex sounds. As a result, our brains have grown forward over our snouts, distorting the shape of our air passages, as well as pressing up during birth against the constraints of the pelvic skeleton. Evolution fits the facts, and may perhaps be correct. Intelligent Design doesn’t fit the facts, and can’t be.
And how about the use of design as an explanation? Let us take Paley’s (1802) classic example, a watch. From the discovery of a watch, we would infer an intelligent designer. But that is not the end of the matter. We would have to further infer that this intelligent designer had access to processes, by which material could be shaped to match the design. Invoking the designer would have to be the beginning of a chain of explanation, not the end of it. Otherwise the whole process is what I have called antiscience, since it tells us to stop thinking when we come across something that we do not understand, which is just when things get really interesting.
This illustrates a general point, and one that I think is of great importance. Advocates of Intelligent Design spend much time drawing our attention to aspects of biology where they see weaknesses in the conventional account. We should be grateful to them for this, but our response should be the exact opposite of what they suggest. We should not view these problems as defeats for naturalistic science, but as opportunities and challenges. Thus several systems which a decade ago appeared irreducibly complex, now appear understandable in relation to simpler components.
Here, I suggest, we have a potent winning strategy; by staying true to ourselves as falllibilists, we make our opponents’ weapons turn against them. We don’t pretend that we know the answer when we don’t, but we can look for it and may even find it. The creationist, on the other hand, already has an answer. He has no need to look, and will find out nothing.
Science feeds on unexplained facts as opportunity and challenge. Science questions. Intelligent Design answers all questions. Therefore Intelligent Design makes science unnecessary. Is that what we want?
In discussion, I predicted that the case would be appealed all the way to the Supreme Court. I was wrong. Judge E. Jones III’s ruling is only binding in the middle district of Pennsylvania, but is such powerful opinion that it is unlikely to be challenged unless at some later date the US Supreme Court acquires a creationist majority.
An earlier version of this post appeared on 3 Quarks Daily
December 20th is the tenth anniversary of the delivery of judgement in Kitzmiller v. Dover, an important anniversary for proponents of evolution science, and Nick Matzke, who coordinated the National Center for Science Education’s efforts at that trial, has celebrated it in the most appropriate possible manner. He has applied the methods of evolutionary tree building to the development of creationism itself in the intervening decade. The results are alarming.
The case arose when Tammy Kitzmiller and the other parents challenged the decision of Dover Area School District Board to introduce the Intelligent Design pseudotext Of Pandas and People to their High School, along with a statement urging students to retain an open mind about Intelligent design as an alternative to Darwin’s theory”. Since the matter has been extensively discussed by me and numerous others, I will simply say that Pandas was an incoherent attack on evolution science, full of factual and logical errors, and that the statement to be read misdescribed evolution as a theory about the origin of life, and claimed that since it was a theory it was uncertain, and, moreover, that there were gaps missing from it. Drafts subpoenaed for the trial also showed that the text had originally referred to “creation science”, being hastily modified when an earlier case established that “creation science” was simply another name for religious creationism.
The case is significant as a test of the creationist claim that Intelligent Design is not a form of religious creationism, but, on the contrary, legitimate science. Judge Jones’s magnificent rejection of this claim runs to 139 legal pages; in brief, he found that this claim was baseless, the textbook error laden, the Designer no other than Christian God (in whom, incidentally, Judge Jones believes), and the arguments offered as evidence for Design scientifically worthless. For this and other reasons, he declared ID to be “a religious view, a mere re-labeling of creationism, and not a scientific theory.” It followed, under the Establishment Clause of the First Amendment of the United States Constitution, that it should not be taught in any publicly funded school. Strictly, Judge Jones’s ruling is only binding in the Middle Circuit of the State of Pennsylvania, but such is the force of its arguments that I do not imagine any challenge elsewhere, unless the US Supreme Court at some future time falls into the hands of creationists.
The creationist response has been to seek yet another, less easily penetrated, form of disguise for their activities. Instead of promoting clearly defined positions, which could be subjected to legal scrutiny, they now speak of teaching the controversy, and put forward so-called Academic Freedom Bills, which invite critical examination of evolution. Who, after all, is opposed to freedom? Shouldn’t students be aware of controversy? And why should evolution be shielded from critical examination? Scientifically speaking, of course, there is no controversy, and neither teachers nor students require special legislative permission before critically examining any concept. So the purpose is, clearly, to provide a figleaf for those who want to claim that the basic concepts of evolution are uncertain, or that creationism provides a worthy alternative.
We have had, in the past decade, 71 of these Academic Freedom Bills introduced, in 16 separate states, and passed into law in 3, while the strategy has evolved as the creationist community has learned from its successes and failures. Matzke’s achievement has been to map this evolution. I imagine no one better qualified. He was the lead member of the National Center for Science Education teisam at the trial. Since then, he has attained a Ph.D. at University of California Berkeley, and spent two years as a post-doc at the National Institute for Mathematical and Biological Synthesis (NIMBioS), housed at the University of Tennessee. He is now recognised as a rising star in his field; a Discovery Early Career Researcher Award Fellow at the Australian National University and the author of some 30 scientific papers on topics related to evolution, with attention also to science education, and to the human impact on the environment.
Matzke has special expertise in molecular phylogeny, the technique by which differences in DNA are used to construct family trees. The basic principle is simple; that a mutation that became established in one species will, unless eliminated by chance, be found in its descendants. We can use such shared mutations to pick out groups of more closely related species, and the family relationships established in this way generally show excellent agreement with the relationships established long since on the basis of anatomical homologies and the fossil record.
Not surprisingly, we can apply the same principle to manuscripts, and Dennis Venema, one of my favourite writers on evolution, has compared the two kinds of application in his series of articles, Genomes as Ancient Texts. But what did surprise me was to learn that the method was applied to mediaeval legal documents as early as 1827, although now texts are examined using programs and criteria of the same kind as those in use to establish DNA phylogenies (see Phylomemetics – Evolutionary Analysis beyond the Gene, free download here). Similar reasoning has been applied to languages since 1850, and both Charles Lyell and Charles Darwin drew attention to the similarities between biological and linguistic evolutionary trees.
What Matzke has now done is to apply the principle to the content of the antievolution bills discussed above. Unfortunately, the paper in which he presents his findings, in the prestigious journal Science, is behind a pay wall, although the National Center for Science Education has published a summary, and NIMBioS has put out a very informative press release, with further accounts in Scientific American podcasts, the Washington Post, and the media company Vocativ.
Anyway, here is what he says, and why it matters.
We can construct a family tree for these antiscience bills. Until around 2006, they were described as Academic Freedom Acts and discuss the teaching of evolution and the origin of life. (Logically, this is a total muddle, since biological evolution does not address the origins of life, any more than chemistry addresses the origin of atoms. Rhetorically, though, it’s a smart move. Creationists often accuse biology teachers of presenting as fact highly speculative theories regarding the origins of life, and although it is decades since biology textbooks did this, mud sticks.) In 2006, an extremely alarming development took place. Ouachita Parish, Louisiana (a Louisiana Parish is much the same thing as a County in other States) developed a policy, in what they renamed a Science Education Act, that lumped together evolution, the origins of life, global warming, and human cloning. The mention of human cloning is purely for effect; we are, and I hope we will choose to remain, a long way from being able to do any such thing, and if we do it will not be in the school science lab. However, it rightly raises alarm.
One truly insidious development is the addition of global warming to the mix. In the US, although not in the UK, the doctrinally conservatism that leaves to creationism is associated with extreme political conservatism, a deep devotion to free markets and suspicion of government, and rejection of the science of global warming, because it implies the need for government (and, worse, inter-government) action. Thus there is an excellent correlation, in the US, between evolution rejection by various faith groups and climate change rejection. Since the fall from power of Tony Abbott in Australia, the United States is I believe the only nation in which one major political party denies that global temperatures are rising, and that fossil fuel burning is responsible. Thus we have the embarrassing spectacle of scientifically illiterate congressmen holding hearings to which they invite cranks and outliers, and doing all they can to sabotage the outline climate agreement recently reached in Paris. As I have said here before, evolution denial is ridiculous but climate change denial is dangerous.
Even more worrying to me is the spread of voucher systems, under which the local government does not run the education system itself, but issues vouchers to all eligible schoolchildren, to pay for their education by non-government schools. MSNBC reports that there are hundreds of such schools teaching creationism as a taxpayer’s expense in nine States and the District of Columbia.
And worst of all is the fact that creationism happens because people want it to. Which means in turn that often there is no effective opposition, either in the community or in the classroom. According to an article in Science, Defeating Creationism in the Courtroom, But Not in the Classroom (2011, 331:404, paywall), timed to roughly match the 5th anniversary of Kitzmiller, around 11% of US biology teachers actually teach creationism, 28% teach evolution according to guidelines, and the remaining 60% avoid the topic because they do not feel prepared to deal with the hostile questioning that it will evoke. Top down imposition of evolution may, alas, be necessary, but it is certainly not sufficient.
Comic relief time: This work has not received universal approbation. At the mendaciously mistitled Evolution News and Views, no less a person than John G. West, political scientist, acolyte of C. S. Lewis, and Vice President of the Discovery Institute, goes to the heart of the matter:
Did Nick Matzke Misuse National Science Foundation Money Intended to Fund Science Research?
Professor West has done us all the great service of looking up the grants that funded Matzke during this work. One of them, he reveals, was earmarked for studying the phylogeny of shellfish. But creationists are not shellfish, so Nick has been very, very naughty. This is not the first time that Discovery Institute fellows have found it necessary to rebuke him. Casey Luskin has pointed out that he is known to have actually received money from the National Center for Science Education (he was employed by them at the time), so no wonder he supports evolution. And two days later David Berlinski criticised him for criticising Stephen Meyer for not using cladistics, because Berlinski thinks you shouldn’t use cladistics, because if you imagine that a cladogram is a geometrical, rather than merely a topological, representation, you can get the wrong answer. (As it happens, the only time I have met this mistake is in the pages of Of Pandas and People, which is roughly where we came in). You can find the whole shocking story here, and I hope that Nick takes these lessons to heart.
1] In the case of biological species, things can get a little more complicated, if only because we are dealing with interbreeding groups, within which genetic material is duplicated and shuffled, rather than unique copies. So species can split while still carrying more than one version of a gene. For example, the genes coding for Type A and Type B blood groups arose by mutation from a common ancestor, at some time more remote than the common ancestor of humans and chimpanzees, and both types were present on both sides of the chimp-human split. Thus a human with blood type A will, with respect to just that single gene, be more closely related to a chimp with the homologous blood type than to a human of blood type B. For this reason, all evolutionary trees are fuzzy. There is also the matter of horizontal transfer, in both biological and meme evoultion.
Keywords: sex, violence, baby swapping, mistaken identity, DNA testing, international relations, Richard Nixon, Viagra, Sixth Mass Extinction
Names can be deceptive. The red panda and the giant panda are not two different varieties of the same species; they are completely different species, and only distantly related. They do not even look very similar. The red panda is much smaller than the giant panda, coloured brown and cream, and has a long striped tail. The giant panda is, of course, black and white, with a very short tail, and black patches over its eyes. These patches help give it the cuddly appearance that makes it so popular in zoos.
Both animals are found in China, although the red panda spills over into Nepal and northern India; both are anatomically carnivores, but live on bamboo; and both have the same kind of false “thumb”. This “thumb” is, really, nothing of the sort, but simply a modified wrist bone, while all five true digits are used in walking. The “thumb” is opposable, meaning that it can be moved to grip against the other digits, but has no joints or claw.
Giant panda in Ocean Park Zoo, Hong Kong. Photo by J. Patrick Fischer through Wikipedia
As early as 1825, Frédéric Cuvier (brother of the more famous Georges) described the red panda and proposed that was related to the racoon. The giant panda, however, did not become known in the West until considerably later. A French missionary in China described a skin in 1869; Teddy Roosevelt Jr and his brother Kermit, sons of President Teddy Roosevelt, saw a giant panda in China in the 1920s (true to family tradition, they promptly shot it); and it was not until 1936 that the first giant panda arrived in a Western zoo. Most zoologists considered it to be a kind of bear, on the basis of its anatomy, although a few thought that the two kinds of “panda” really were closely related. The matter was finally and conclusively resolved by comparing the DNA of both animals with that of other species. As expected, the giant panda belongs to the bear family, while it turns out that the red panda is in a genus all of its own, with skunks, raccoons and badgers as its closest relatives. But you do not find the false thumb in raccoons and skunks, and you do not find it in polar bears and grizzlies. So it is not a shared feature of this branch of the carnivore family tree, but a separate similar development in the two “pandas”. A similar false thumb is also found in some species of mole. These are examples of what is called parallel evolution, in which the same modification arises independently in different species. To use technical language, the thumbs are analogous (similar, and performing the same function), but not homologous (not a feature inherited from a common ancestor).
Update: the film Judgement Day, regarding the Dover trial,is now available to UK viewers here.
The giant panda occupies a special place in US legal history. It was given a starring role in the 1989 “alternative textbook”, Of Pandas and People, an attack on the science of evolution in general, and on common descent in particular. The book carries an attractive photo of a giant panda on its cover, and argues at great length that since the analogies between the “thumbs” of the red and giant panda are not due to common descent, therefore all anatomical arguments in favour of common descent should be regarded as suspect. One particular School Board, in Dover, Pennsylvania, voted to introduce this book into its high school, with a statement to be read to students. This statement described the book as a way of exploring “Intelligent Design”, and declared that “Darwin’s Theory … is not a fact. Gaps in the Theory exist for which there is no evidence… Intelligent Design is an explanation of the origin of life that differs from Darwin’s view.”
I should explain that “Intelligent Design” in this context means the view that biological complexity is due to the activity of an intelligent designer. It offers no suggestions as to how or why the designer operates, or how the design comes to be embodied, so I find it difficult to see how it is an explanation of anything. The reference to the origin of life is bizarre, given that Darwinexplicitly refused to discuss this topic. As for the expression “Darwin’s Theory”, and the creationist obsession with Darwin, I have already discussed these here and here.
The biology teachers, very courageously, refused to read out any such statement, because they said they could not tell their students what was simply not true, so the School Board told the Principal to read it to the class instead. A group of outraged parents promptly took the School Board to court, on the grounds that Intelligent Design is not a scientific theory but a religiously inspired doctrine. This would mean that propounding it in a publicly funded school is contrary to the establishment Clause of the First Amendment to the US Constitution. During the trial, the plaintiffs were able to demand drafts of the book as evidence, and discovered that it had its own evolutionary history. It was originally written in terms of “creation science” and “creationism”, terms that for legal reasons were transformed by horizontal meme transfer into “intelligent design”. One of the subpoenaed drafts even contained the expression “cIntelligent Designism”. The Missing Link!
For this and many other reasons, the judge had no difficulty in concluding that “intelligent design” was nothing more than religiously motivated creationism. He set out his reasons in a detailed and powerful judgement, and while his decision is strictly applicable only to the States covered by that particular court, it seems most unlikely to be challenged unless the US Supreme Court falls into the hands of extreme religious conservatives.
For a work arguing in favour of Intelligent Design, the panda was a singularly unfortunate choice. The so-called puzzle of the two kinds of “panda” was solved over a century ago, and the results confirmed much more recently by modern molecular techniques. All the more reason to trust evolution science. The inflexible “thumb” is not what a designer would have chosen, but what the evolving animal was stuck with. All five of the panda’s claws are used for walking or climbing, so it was not possible to coopt one of these to hold on to bamboo, even though the extra joints present inside a real thumb would have made it much better at this job. Finally, the panda’s digestive system is very poorly adapted to its way of life, because it is descended from carnivores. An intelligent designer would have given the panda a digestive system rather like that of a cow. The panda is a wonderfully clear example of how an animal’s form is constrained by its evolutionary history. In fact, the great essayist Stephen Jay Gould named one of his books in its honour way back in 1980, and http://www.pandasthumb.org, one of the world’s top science blogs, follows his lead.
So what were the authors of Of Pandas and People thinking? They were neither stupid nor unqualified, and were well aware of, and indeed they themselves quote, the scientific literature that showed how the “problem” of panda species had long since been resolved. So how could they have imagined that they were putting forward a credible argument? There is a serious philosophical or psychological point here. It seems to me that for them and their supporters, the problem of the pandas really did illustrate an argument against evolution science. Some comparative anatomists had thought that the two kinds of panda were closely related. They were wrong. Therefore, the argument runs, comparative anatomy in the service of evolution is untrustworthy. Creationists think in absolutes. So they regard the awareness of fallibility, which lies at the very heart of the scientific method, as an admission of weakness. This could explain why creationism is so appealing to lawyers, who rely on cases being finally settled, and to conservative theologians, who regard their dogmas as established and revision as heresy.
Pandas have eating problems
It was the giant panda that graced the front cover of Pandas, that appears in the logo of the World Wildlife Fund, and that pulls in visitors to zoos Edinburgh zoo even has a pandacam for remote viewing). Panda diplomacy also played a role in the restoration of normal relations between China and the West, one of the major achievements of the much-maligned Nixon administration. The chubby-faced cuddly looking creature, with the big black patches round its eyes, has great emotional appeal. Unfortunately, its very survival in the wild is threatened, and attempts to maintain numbers in captivity have run into great difficulties.
Pandas (from here on in,I just mean giant pandas) have painted themselves into a corner, adapting to a very narrow niche, for which their ancestry had not really equipped them. They live almost entirely on bamboo. Unfortunately, bamboo is of very low nutritional value to them. Pandas are, after all, members of the carnivore family, and have carnivore type digestive systems and enzymes, leaving them dependent on bacteria in their gut to break down their food. This is such an inefficient system that they need to eat around 20 kg a day, and in the wild just doing this can take them up to 14 hours. They need very powerful jaw muscles because of the chewing involved, and these, together with wide cheeks to accommodate large grinding molars, are what give the pandas their appealing round faces. We have fossil skulls and teeth showing that pandas had already adapted in this way 2 million years ago. But fossilised bones cannot tell us the history of those appealing black eye patches, which are probably favoured by evolution in the pandas’ snowy habitat, because they reduce glare, like footballers’ facepaint.
Pandas can only survive in areas where more than one species of bamboo is flourishing, so that when one species flowers and dies back, they do not lose their only food source. They extract so little nutrition from their food that they have little energy to spare, and find it a problem to make their way up steep slopes. This may not have mattered too much in their original habitat in the Chinese lowlands, but now that people have taken up all the land suitable for agriculture, they find themselves forced into shrinking and fragmented habitats in the mountains. Climate change is expected to make things even worse. There are probably fewer than 3000 surviving n the wild. So the number in captivity, which now exceeds 300, is a considerable fraction of the total population.
Sex problems too
Update, 9 July 2014: Tian Tian, the Edinburgh zoo panda who was artificially inseminated in April after she and her partner, Yang Guang, failed to mate naturally, has conceived, but it is not yet known if she is pregnant, as the embryo is not implanted into the womb immediately in pandas.
In the wild, pandas are solitary animals, each one marking its own range by clawing and spraying urine, but they do gather together during the annual breeding season, when their endeavours are evidently successful, otherwise they would not be here. However, it has turned out to be enormously difficult to breed pandas in captivity, a feat not accomplished at all until 1963. What’s the problem? Why not just put a male and a female panda together and let them get on with it?
Firstly, the female panda only comes into heat once a year, for about three days, during which she is only fertile for 12 to 24 hours (this fertile period can be detected by testing her urine). Then, most attempted romantic encounters proved very disappointing. The male (according to the BBC, no less) has a very short penis, so that accurate positioning is necessary, and they are not very good at doing this. Moreover, preliminaries in the wild involve fighting among males for the privilege of mating, and this spectacle seems to be an important part of what it takes to get the female interested. So despite measures ranging from sex education videos, to stimulating the males with sticks of bamboo carrying the female scent, to the use of Viagra, managed encounters in the zoo often end in disappointment or even violence. “Close, but no cigar” is how Edinburgh Zoo described the situation of their own two pandas, when in April 2012 Yang Guang (Sunshine) mounted female panda Tian Tian (Sweetie) several times, without full mating taking place.
The present successful breeding program in China has resorted to artificial insemination (don’t ask!) However, that does not put an end to the problems. Pandas very often display pseudo-pregnancies, quite difficult to distinguish from the real thing, even by hormonal testing. Ultrasound can be helpful here, but requires considerable skill because of the smallness of the foetus, as well as the cooperation of the animal. (The mother weighs around 100 kg or more; the new-born offspring, a mere 100g.) In human and most animal pregnancy, we know when to start the countdown to birth, but not with pandas. These, like other bears, show delayed implantation of the foetus. So the time between fertilisation and birth can range from 11 weeks to 11 months. Pregnancy can end in miscarriage, as recently happened at Edinburgh Zoo. Finally, because of the small size of the foetus, and the common occurrence of pseudo-pregnancies, true pregnancy does not become obvious until shortly before birth.
Pandas usually give birth to two clubs at a time, but only make enough milk for one. So the expert panda breeders at the world’s leading centre in Chengdu have resorted to trickery, caring for the abandoned cub in an incubator, swapping the two clubs around when their mother is not paying attention, and supplementing the mother’s milk with imitation bear milk. Both cubs do, however, need their share of mother’s attention. They have weak immune systems, so they rely on antibodies in their mother’s milk. They also need help in defecating, which the mother supplies by stroking their lower abdomens with her tongue. However, this particular problem clearly resolves itself by adulthood, since a full-grown panda makes 40 panda-pats a day.
The panda breeding programme is big business, with the Chinese retaining ownership of the beasts, and renting them out to Western zoos for $1 million a year. This is over and above the cost of looking after them. Even so, major zoos consider this a worthwhile investment, because of added visitors and publicity. Centre-bred pandas are now also being reintroduced into the wild. Suitable habitat has been bought, and will no doubt in due course be a major attraction for eco-tourists. Keepers involved in the reintroduction have been dressing up as pandas, in the hope that their charges will feel more at home when released. However, critics of reintroduction point out that the entire exercise is meaningless unless these pandas are given enough protected habitat, and the first released panda died after only a few months in the wild.
And finally, the hard question
Biologists warn that we are on the threshold of a sixth great extinction, comparable to the demise of the dinosaurs. Unless we change our ways, or brute circumstance changes them for us, we could lose 75% of living mammals within the next 300 years. To say nothing of other life-forms, and with consequences for ourselves that we can only guess at. Amidst this mayhem, is the panda worth saving? If so, why? If not, why not?
This piece originally appeared at http://www.3quarksdaily.com/3quarksdaily/2013/11/the-problem-with-pandas.html#sthash.ONwwiWM7.dpuf