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Black swans and other deviations: like evolution, all scientific theories are a work in progress
Discussions about the nature of science and scientific theories are often confused by the outdated view that such theories are rendered false when anomalies arise. The notion of a scientific theory as a static object should be replaced with the more current view that it is part of a living research programme, which can broaden its scope into new areas.
For example, take the hypothesis that all swans are white, which seemed pretty good to Europeans until Dutch explorers found black swans in Australia in 1636. So what happens to our hypothesis? There are a number of options.
1) Redefine swan-ness to include whiteness. Then black swans aren’t really swans, and the hypothesis remains true by definition.
2) It’s been disproved. Discard it.
3) Compare different species of swan the world over, and see how well black swans fit in.
(1) is the least useful. Definitions can only tell us about how we are using words. They tell us nothing about the world that those words attempt to describe. (2) is based on the common-sense idea that hypotheses should be discarded when falsified by observation. This was the idea put forward by philosopher Karl Popper in the 1930s, to distinguish between science and pseudoscience.
Read the rest of this entryIntelligent Design or intricate deception? What I told students during the Kitzmiller trial
The University of North Texas, where I was teaching in 2005
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.
Of Pandas and People, the pseudo-textbook at the centre of the Kitzmiller case
This is a rather unusual presentation. It is the only presentation that I have ever given in response to a specific request from the [then] President of the United States, who has given as his opinion that Intelligent Design should be discussed in schools. It is the only presentation in which you will see me, a chemistry professor, practicing philosophy and even biblical exegisis; and I should warn you that I am practicing without a license. It is the only presentation I have ever given with the expectation that a number of people in the audience will be actively hostile to what I intend to say, because the point of view that I stand for is often misrepresented in this society as being hostile to religion.
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 Darwin-Wallace medal awarded by the Linnaean Society
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.
Monument to Maimonides in Cordoba. Photo by Justojosemm through Wikimedia
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
Darwin, Wallace, Evolution, and Atheism (Part II of Bears, whales, God, Darwin, and Peter Hitchens)
[For Part I, see here]
Peter Hitchens, younger brother of the late Christopher, says in the notorious London Daily Mail that the implication of evolution “is plainly atheistical, and if its truth could be proved, then the truth of atheism could be proved. I believe that is its purpose, and that it is silly to pretend otherwise.” Pat Robertson claims that “the evolutionists worship atheism.” Richard Dawkins tells us that he lost his faith in God when he learned about evolution, the claim that evolution is intrinsically atheistical is used repeatedly by advocates of creationism, including that bizarre oxymoron, “scientific creationism”, and the Discovery Institute’s Wedge Document describes it as part of a malignant materialism that debunks traditional views of both God and man. Discovery Institute fellows also coached Ann Coulter, who went on to tell us that evolution is itself a discredited religion, related to the mental disorders of liberalism and godlessness.
Yet from the very outset there have been believers who actively welcomed evolution. Asa Gray, the botanist to whom Darwin dedicated his own book Forms of Flowers, saw evolution as the natural process through which God worked. Charles Kingsley, the Christian social reformer and historian now best remembered for The Water Babies, wrote appreciatively to Darwin, on previewing The Origin of Species, that a Deity who created “primal forms capable of self development” was “a loftier thought” than one who had created each kind separately. In our own time, we have evolution theology and Evolution Sunday. Ken Miller, a committed Catholic, is prominent as molecular biologist, textbook writer, and legal witness on behalf of evolution, while Dennis Venema’s postings on the website of BioLogos, an organization dedicated to the acceptance of science from a Christian perspective, are model expositions of evolutionary science.
Against this background, it may be helpful to look at the religious views of Charles Darwin himself, and also those of Alfred Russel Wallace, the two independent originators of the concept of evolution as the inevitable outcome of natural selection. Warning: this post will be longer than most. The Victorians do not lend themselves to sound bites.
Darwin’s private Autobiographies include a short but revealing chapter on religious belief. This the family regarded as so contentious that it was not made public in full until 1958. Darwin initially contemplated becoming a clergyman. He tells us that he “did not then in the least doubt that strict and electoral truth of every word in the Bible”, and was much impressed by Paley’s argument from the perfection of individual organisms to the existence of an intelligent creator, He was still quite orthodox while on the Beagle, but in the two years after his return he reconsidered his position, and gradually came to reject orthodox religion on historical, logical, philosophical, and indeed moral grounds. As he later wrote,
“I can indeed hardly see how anyone ought to wish Christianity to be true; for if so the plain language of the text seems to show that the men who do not believe, and this would include my Father, Brother and almost all my best friends, will be everlastingly punished.
And this is a damnable doctrine.”
As for the implications of science, Darwin’s conclusions are interesting. “The old argument of design in nature, as given by Paley … fails, now that the law of natural selection has been discovered…. Everything in nature is the result of fixed laws.” Regarding what he called, despite the deaths of three of his children, “the generally beneficent arrangement of the world”, this he explained as itself the result of evolution. In order to survive, creatures must be so constituted that pleasure outweighs pain and suffering, which “if long continued, causes depression and lessens the power of action.” As for the opposite argument, “The very old argument from the existence of suffering against the existence of an intelligence as cause seems to be a strong one; whereas… the presence of much suffering agrees well with the view that all organic beings have been developed through variation and natural selection.” In short, the argument from the goodness of the world and the counter-argument from suffering both fail, since the capacities to experience pleasure and suffering, and the balance between them, are themselves explained as evolved adaptations.
One argument, however, retained conviction at the time when he was writing On the Origin of Specie, namely “the extreme difficulty or rather impossibility of conceiving this immense and wonderful universe… as a result of blind chance or necessity.” Notice that Darwin makes a clear distinction, which today’s “Intelligent Design” advocates systematically blur, between Paley’s argument from the design of particular things (rejected, as we saw earlier), and the more powerful argument from the possible presence of design in the universe as a whole. The latter he finds convincing enough to say, at the very time that he was composing On the Origin of Species, that “I deserve to be called a Theist”.
Later, Darwin wonders, “can the mind of man, which has… been developed from a mind as low as that possessed by the lowest animal, be trusted when it draws such grand conclusions? … The mystery of the beginning of all things is insoluble by us, and I for one must be content to remain an Agnostic.” Our minds evolved to enable us to deal with commonplace reality, and we must doubt whether they are adequate instruments for speculating so far beyond that. “Agnostic” was a term then newly coined by his friend and prominent supporter, Thomas Huxley, and refers, not to a wishy-washy uncertainty, but to the principled conviction that there was no adequate way of deciding the question.
Alfred Russel Wallace is a much more complicated case. He seems to us self-contradictory and changeable, an opponent of the supernatural who nonetheless took Spiritualism seriously. He was also much more wordy than Darwin; his autobiography runs to two thick volumes. I have therefore relied mainly on secondary sources,[1] together with his review of Lyell’s writings on geology, in the April 1869 issue of The Quarterly Review[2], and his 1871 reply to critics.
In his teens, Wallace came into contact with the reformist ideas of Robert Owen, and abandoned conventional religion, with its emphasis on original sin, for a belief in human improvability based on the natural sense of justice. Throughout his adult life, he described himself as a Socialist, and wrote a book in favour of the nationalization of land. He seems to believe in a Creator, and indeed advances, as an argument in favour of evolution, that separate design for every creature would reduce that Creator to the level of a second-rate craftsman[3] (compare Charles Kingsley’s comments, above). However, only two years before formulating his own version of the theory of natural selection, he had written of how far, in his view, the beauty and diversity of the forms of living things goes beyond what could, for him, be explained in terms of their requirements.[4]
This last conclusion may help make sense of his 1869 review of Lyell, in which he asserted that there were things about humanity, in particular, that could not be explained by natural selection. Abstract thought, moral sense, and the design of the hand, all as much present in what he called the savage as in civilized man, seemed to him superfluous to the requirements of the savage’s life. This despite having lived among such savages while collecting specimens, and observing the demanding nature of their lifestyles, the skill of their toolmaking, and the subtleties of their social organization. He also makes the linked arguments that evolution cannot explain the development of consciousness (for contrary opinions, see Dennett’s Kinds of Minds and Cairns-Smith’s Evolving the Mind), and that materialism cannot explain how consciousness could exist at all (here, I think, Wallace is referring to a problem that we are no nearer solving now than we were then).
But does this mean that he was willing to embrace the supernatural? Quite the reverse! In his answers to critics, he says very plainly that he does no such thing. What he does do, is reject materialism. There is more in the universe than matter, but nothing that is beyond the scope of natural science.
So what of Peter Hitchens’s (and, for what it’s worth, Pat Robinson’s) claim, given that neither Darwin nor Wallace could be pigeonholed as atheists, and that Wallace was not even a materialist? Totally false. Grossly insulting to the entire scientific community, portrayed as choosing its key concepts according to an ideological agenda quite outside science. As I said before regarding all evolution denialism, dependent on a conspiracy theory. And a warning to all of us; if this is typical of journalistic comment in the areas that we know about, like science, how should we regard such comment in areas that we cannot so readily examine, like Syria?
There remain some serious questions. Is it possible to accept evolution without being an atheist? Quite obviously, yes, as Darwin, Wallace, and many examples listed here clearly show. But human psychology is notoriously quirky and tolerant of self-contradictions). So, as a matter of logic, is religious belief compatible with the acceptance of the fact of evolution?
The answer, surely, must depend on the kind of religion, and here my sympathies lie entirely with their Evolution Sunday crowd. Evolution demolishes one version of the argument from design, but even when I was a believer I did not find that version convincing. And, for the reasons spelt out over the past 150 years by Kingsley, Darwin, and many others, evolution poses no new problems for religion in general, and indeed may blunt some of the traditional arguments used against it.
What is not consistent, either with present-day scientific knowledge, or with any kind of scientific approach to reality, is a religion dependent on an overriding belief in the literal truth of its sacred text. Such a position renders impossible any sensible discussion of evolution, or of nature in general, or, indeed, of God.
[1] See e.g. Helena Cronin’s The Ant and the Peacock, which discusses Darwin’s and Wallace is different views on sexual selection and cooperation; Natural Selection and and Beyond, ed. Charles H Smith and George Beccaloni.
[2] Confusingly indexed in QR under Lyell, not Wallace.
[3] Smith and Beccaloni, p. 327.
[4] Ibid p. 370.
Bears, whales, God, Darwin, and Peter Hitchens (Part I)
Can bears turn into whales? Peter Hitchens (PH) asks this question in two successive instalments of an anti-evolution tirade of the kind that gives ignorance a bad name. Normally I would not have bothered with such nonsense, especially since Jerry Coyne at WEIT has already dismembered what with PH passes for reasoning in greater detail than it deserves. However, PH does raise an interesting question or two, and makes one assertion is so breathtaking in its combination of arrogance and ignorance that I cannot forbear from discussing it. Let me deal with these matters in turn.
The first question is, can bears turn into whales? The suggestion is based on a remark by Darwin, in the first edition of On the Origin of Species, which he dropped it in later editions as being too speculative. However, PH still chooses, over 150 years later, to cite it as evidence that Darwin’s whole research programme, and by implication the entire structure of the life sciences as they have developed since that time, is really very silly. As to why we all indulge in such silliness, PH’s answer, which I will analyse later, is as ridiculous as it is insulting.
The answer to the question, by the way, is no. Of course, no presently existing species is capable of evolving into another presently existing species, any more than PH is capable of evolving into his late lamented brother, nor would Darwin ever have suggested such a thing. If we rephrase the question a little more precisely, do bears and whales share a relatively recent common ancestor, the answer is still no. Bears do in fact share a relatively recent ancestor with seals and walruses, but their last common ancestor with whales was back in the Cretaceous.
The obvious question then arising is this: if whales are not related to bears then what are they related to? Forty years ago, we didn’t have a precise answer to that question. Now we do, and PH could have found it easy enough, just by looking up whale evolution in Wikipedia. And while PH is understandably concerned about erroneous assignments, since the only fossil he seems to know about is the Piltdown forgery, Wikipedia will also provide him with a list of 43 separate extinct families of precursors of modern whales. But perhaps PH is a Wikipedia snob, or perhaps these articles, replete as they are with terms like “artiodactyl” and “cladogram”, are above his technical reading level. In the latter case, I would refer him to an excellent National Geographic article; in the former to either of two recent but more technical reviews, here and here. I will be writing about whale evolution at much greater length elsewhere, showing as it does a beautiful coming together of three separate lines of evidence; from the fossil record sequence, from anatomical homologies, and from molecular phylogeny.
My point here is a rather obvious one. PH admits that he is ignorant about evolution. Nothing to be ashamed of there. After all, he is a busy man, and has his own priorities, and if he can’t find the time to learn what kind of place the natural world is, and how we fit into it, then that’s his own business. But what he should be most deeply ashamed of, is his decision to write, not once but twice, about such a subject without first bothering to inform himself.
Despite his self-proclaimed ignorance, PH claims to have penetrated the motivation of the scientific community in its acceptance of what he describes, in rather simplistic and old-fashioned language, as “the theory of evolution by natural selection.” What he tells us of this theory is that the motivation is fundamentally theological, or rather, anti-theological. To quote, “I will re-state it, yet again. It is that I am quite prepared to accept that it may be true, though I should personally be sorry if it turned out to be so, as its implication is plainly atheistical, and if its truth could be proved, then the truth of atheism could be proved. I believe that is its purpose, and that it is silly to pretend otherwise.” [My emphasis]
So this is a clear statement of what PH considers to be the purpose of the theory; not to make sense of nature, as we scientists pretend, but to prove the truth of atheism. Well, questions of motivation are always interesting, if difficult to settle, but in this particular case we happen to be in a position to decide the truth or otherwise of PH’s claims. The theory of evolution by natural selection was first clearly formulated by two separate individuals, initially working independently, Alfred Russel Wallace and Charles Darwin. We know a great deal, in both cases, about their attitudes to religion, and Darwin in particular has left us a detailed description of how his views changed over time, as a result in large part of the evidence that he collected while developing and testing his theory. Both these great scientists changed their opinions on religious and spiritual matters during their working lives. Neither developed their theories in pursuit of a theological agenda, and if they had done so, that would have amounted to professional malpractice. The reality is very different, much more interesting than anything PH could have imagined, and we will return to this in the next part.
Don’t say “Darwin” when you mean “evolution”. Part II, Naming and Framing
In Part I, I stated that if you equate evolution with Darwin, or, worse, if you describe our knowledge of evolution as “Darwin’s theory”, you are guilty of scientific, logical, historical, and pedagogic errors, and playing into the hands of the Creationists. Here I enlarge on these claims, and make recommendations about how best to describe both our own position, and that of our opponents.
Firstly, the historical. Darwin was well aware that his own achievements were part of a prolonged process (see Rebecca Stott’s outstanding recent book, Darwin’s Ghosts). After all, Alfred Russel Wallace had come up, quite independently, with the concept of natural selection, as perhaps did one or two other, more obscure, figures, while thinkers as diverse as Erasmus Darwin (Charles’s grandfather), Lamarck, and Geoffroy Saint-Hilaire had developed their own ideas about the mutability of species.
Secondly, the scientific and pedagogical. As I indicated in Part I, Darwin’s theory (as we can call it, in the framework of its own time) did not contain within it anything resembling our modern concepts of genetics and mutation, while the identification of DNA as the material depository of genetic information lay almost a century in the future. When we teach about evolution today, we can use 21st-century molecular biology as our starting point; or we can point to the rich detail of the fossil record as examined by present-day techniques (think how recently we learned about feathered dinosaurs); or we can do competently what Haeckel did rather incompetently, and trace common features of embryonic development. Or we can talk about the cases of evolution being studied in the laboratory, or about the diversification of fish species in the natural laboratories provided by the great lakes of Africa. These topics show a live and vibrant science, greatly extending the concepts of a century and a half ago.
Finally, and most importantly, the logical and the rhetorical. Those who succeed in framing the terms of debate will gain an enormous advantage, regardless of the actual merits of their position. Lakoff (Don’t Think an Elephant) analyses how effectively the American Right have used this strategy, and as the current presidential election shows, the American Right and Creationism are now closely intertwined.
Attaching a proper name to a viewpoint suggests that it is individual, rather than part of a consensus, and marks it as incomplete, if not indeed superseded. Thus we speak of a Marxist or Freudian interpretation of history and human behaviour, and of Newtonian physics in contrast to relativistic or quantum physics. From this it is but a short step to the use of a proper name to discredit a point of view, rather like the use of proper names by the early Church to label damnable heresies, or by the Communist Party of the Soviet Union to label equally damnable ideological deviations.
We can now understand the Creationists’ excessive, almost pathological, obsession with Darwin. Thus in the Creationist “supplementary textbook”, Explore Evolution, produced by the Discovery Institute and now being promoted by its satellites, I counted 29 occurrences of Darwin’s name or some variant of it within the 11 pages of the Introduction (but amazingly no reference to Darwin in the Index). Behe names his books Darwin’s Black Box and The Edge of Evolution …The Limits of Darwinism, Johnson calls his Darwin on Trial and Defeating Darwinism by Opening Minds, while Scotland’s own Antony Latham offers us The Naked Emperor: Darwinism Exposed.
I therefore propose what I might call the “Dalton test” for using Darwin’s name. If you were talking about chemistry rather than biology, would you mention Dalton? If not, why mention Darwin? When Darwin’s name is invoked in the context of history of ideas (Gould, Ever since Darwin; Darwin’s Ghosts, already mentioned), or as a deliberately provocative rhetorical device (Dennett, Darwin’s Dangerous Idea) this is obviously appropriate. When “Darwin” is used as lazy shorthand for evolutionary biology, it is not; and every time we do this, we play into the hands of our opponents.
“Theory of evolution”, as a synonym for evolutionary science, is another expression to avoid. We are all familiar with the bogus argument that evolution is a theory, theories are uncertain, and therefore evolution is uncertain. We all know the refutation: that “theory” has a special meaning in science, but this logical rebuttal does not stop the argument from being used to great rhetorical effect. More fundamentally, the emphasis on theory does biology (and Darwin himself) far less than justice. The reason that Darwin is a major figure, while Wallace is not, despite independent discovery of the same central concept, is the depth of observational detail with which Darwin was able to support his insights.
There are also deeper reasons for avoiding the emphasis on “theory”. Strategically, it evokes a fortress mentality, as if evolutionary biology were under siege and the experimental evidence had been summoned to relieve it. Rhetorically, that is a losing posture. Pedagogically, it is equally mistaken. The development of evolutionary thought from Buffon to the present day is a beautiful example of how science works, with observations triggering ideas and those ideas raising new questions for observers. To place theory first as if observation came second (or even the other way round) is to miss the entire point.
Labelling is a two-way street, and we also need our own language to describe the opponents of evolution science. Let’s refer to all those who deny a common ancestry for complex organisms as Creationists, since they are postulating a separate creation for each separate kind.[1] I would also propose the broader blanket term Supernaturalist for anyone who claims that biology can never be explained by the ordinary laws of nature, since the intervention of an entity not constrained by these laws of nature is by definition supernatural. By this clear and rigorous definition, the website Uncommon Descent, while most revealingly claiming to serve the Intelligent Design community, is self-confessedly Creationist. All Creationists are Supernaturalists, but a few Supernaturalists (e.g. Michael Behe) are not Creationists. Creationist supporters of Intelligent Design tend to keep quiet about their Creationism, and to vociferously assert that Creationism and Intelligent Design are completely different concepts. However, least two of the three officers of Glasgow’s Centre for Intelligent Design (C4ID) are undoubtedly Creationists, as is Phillip Johnson, guiding spirit of the Discovery Institute, and many of that Institute’s Fellows including some that have visited the UK to take part in C4ID events, and Intelligent Design advocates should always be closely questioned as to their own views on common descent, and on the science that underlies it.
In conclusion, we must choose our own words, rather than letting our opponents choose our words for us, and those words should clearly label them for what they are.
As for Darwin, while giving him all due honour, we should make it clear that what we now possess is a much more complex and complete system than he could ever have imagined. There are the facts of evolution (the plural is important), and there are suggested theoretical explanations for these facts; together, these make up the present-day science of evolution. That is how it is, and that is how we should describe it.
[1] We should specify that this is how we are using the term, to pre-empt the deliberate confusion of this issue with such unrelated matters as the origin of life, or even of the Universe. And I specified complex organisms because some Creationists (see e.g. Explore Evolution) misuse genuine debate about hybridisation in the simplest life forms as cover for the doctrine of separate creation of kinds. Students of Creationism will recognise the term “kinds”, its role in the pseudoscience of Baraminology, and its relationship to Genesis 1:12-23.
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