Category Archives: Human evolution
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, and pressing up 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
This article explains exactly what endogenous retroviruses are, the many distinctive features that leave no doubt as to their identity, and how they provide crushingly strong evidence for common ancestry. The argument from endogenous retroviruses to evolution in general, and to specific family trees, is to my mind one of the most immediately convincing (compare http://www.talkorigins.org/pdf/comdesc.pdf, 29+ Evidences for Macroevolution, Sec. 4.5).
As the article points out, the odds against any ERV occurring in the same place in humans and chimps is about 1 in 10^4; humans and chimps share 100,000 ERVs in the same locations, and the odds against this would then be 1 in 10^400,000. By my arithmetic, allowing for the 0.1% where there is no match changes this to 1 in 10^399,800, still a ridiculously vast number.
I would also have welcomed numbers showing where gorillas, for instance, fit into the picture, and numbers of ERVs specific to each species.
The final section of this post is addressed to those who, like the author, regard the Bible as divinely inspired but not as literally true. The argument goes back to Maimonides, if not Augustine, and here forms part of the ongoing civil war within the Abrahamic religions between Fundamentalists and Modernists. Not my battle.
Introduction to Endogenous Retroviruses
Advances in biochemical technology since 2000 have allowed us to determine the full DNA sequences for humans and other animals. This new information has illuminated our evolutionary history. A number of patterns in our DNA are consistent with a common ancestry of humans and other primates.
One such genetic feature is the distribution of endogenous retroviruses (ERVs) in our genomes. As most readers know, viruses work by introducing their RNA or DNA into a host cell, and hijacking the host cell’s genetic machinery to start making more copies of the virus. Some viruses, called “retroviruses”, do this by having their RNA transcribed into DNA, which then gets inserted into the cell’s DNA genome. (This is considered “retro”, because normally in a cell DNA is transcribed into RNA, not the other way around). The HIV virus that causes AIDS is an example of a retrovirus. Once the…
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The Science Meets Religion website, by the information scientist David Bailey, has a Q&A page that addresses the most common and most plausible scientific objections raised by creationists to the science of evolution. Twenty-six specific questions are chosen, and answered in a series of brief essays on such topics as complexity, information theory, radiometric dating, fossils, speciation, and thermodynamics. For each of these, Bailey gives a straightforward statement of the creationist arguments, and then succinctly lays out the evidence for the contrary viewpoint. The rebuttals of creationism are all the more crushing for being written with judicial dispassion.
The style is accessible enough for a high school student to read with enjoyment, but the scholarship behind it is impressive. For example, the discussion of alleged missing links between humans and non-human apes gives fourteen separate references to discoveries in the last eventful half dozen years. The essays on dating methods list, and refute, nine separate creationist claims, and refer to numerous scientific sources. These include authoritative on-line reviews such as Wiens and Dalrymple on radiometric dating and Dalrymple on the fallacies in the “creation science” arguments for a young Earth, as well as some key papers fron the primary research literature. The bibliography has (at present) 764 entries, more than 50 of them from 2015, refers to the scientific, creationist, and theological literature, as well as human behaviour and its link (or not) to religious belief, and is regularly updated (most recently last September). You will find here articles on everything from the latest word on Homo naledi to the microwave spectra of distant galaxies to divorce rates.
Bailey is himself a committed Christian, and joins other Christian writers such as Dennis Venema at Biologos and Roger Wiens (whose web page on radiometric dating I cite above) in showing that the “controversy” between evolution and creationism is not so much a conflict between science and religion, as a battle within religion itself. As the Scopes trial anniversary reminded us, this civil war in its current form dates back a century, to the conflict between Modernists and Fundamentalists. (The underlying issues, of course, are far older, and Bailey’s bibliography gives three references to Augustine.)
Some of my fellow unbelievers think the best way to advance the cause of enlightenment is to attack religion. I regard this course as mistaken, psychologically, philosophically, historically, educationally, and tactically. I think that the followers of any religion face major problems, but they are their problems, and it is not my place to lecture them on how they should be resolved.
In addition, affirmations of the validity of evolution and Old Earth geology have far greater power when they come from within the body of believers. Anyone who chooses to be misled by the claim that evolution is uncertain because it is a theory, or who prefers the absurdities of Flood Geology to the evidence of their own eyes, is in need of intellectual liberation, but such liberation can only come from within, and will come far more readily given the encouragement of members of their own faith community.
I conclude by illustrating this point with a paragraph from Bailey’s critique of Intelligent Design:
One overriding difficulty with both the creationist and intelligent design movements is that invoking a Creator or Designer whenever one encounters a difficult question is a “thinking stopper.” Such an approach places numerous grand questions of our existence off-limits to human investigation, buried in the inscrutable mind of a mysterious supreme Being: “Why was the earth (or the universe in general) designed the way it was?” “How did the design and creative processes proceed?” “What physical laws were employed?” “Why those particular laws?” “What prompted the creation?” “Have other earths or universes been designed or created?” “Where are they?” Surely there is a more fruitful avenue for finding a harmony between science and religion than just saying “God created and/or designed it that way” and then deeming it either unnecessary or inappropriate to inquire further.
Here we have a powerful statement, far more powerful because it comes from a committed believer, of why such doctrines are not merely stupid irrelevancies, but active obstacles in the search for religious, as well as scientific, understanding.
David Bailey’s professional website is here; his professional homes are Lawrence Berkeley Laboratory and (current primary affiliation) University of California, Davis. I learnt of his work through a post on Scott Buchanan’s Letters to Creationists. David uses the hominin evolutionary tree that I show here (taken from Scientific American’s September 2014 special issue on evolution) to illustrate what we do and do not know about our species’ grandparents and great-uncles.
What is the purpose of this examination?
We have the purpose of preventing bigots and ignoramuses from controlling the education of the United States, and that is all.
Inherit the Wind, the prism through which the public sees the Scopes Trial, is a travesty. William Jennings Bryan, who prosecuted Scopes, was neither a buffoon nor a biblical literalist but moved by deep concerns that continue to merit attention. He did not protest at the leniency of Scopes’s punishment, but offered to pay the fine out of his own pocket. Nor did he collapse in defeat at the end of the trial, but drove hundreds of miles, and delivered two major speeches, before dying in his sleep a week later. Scopes, on trial for the crime of teaching evolution in Tennessee state school, was never at risk of prison. He was no martyr, but a willing participant in a test case, actively sought by the American Civil Liberties Union (ACLU), and his subsequent career was as geologist, not school teacher. He was found guilty, quite understandably given the wording of the law. On appeal, his conviction was quashed on a technicality, bypassing the need to rule on the deeper issues, much to the dismay of his supporters. Worse; on what we would now regard as the crucial issue, whether the law against teaching evolution in State schools violated the constitutional separation of Church and State, the Tennessee Supreme Court ruled that
We are not able to see how the prohibition of teaching the theory that man has descended from a lower order of animals gives preference to any religious establishment or mode of worship.
The law prohibiting the teaching of evolution affected textbooks for a while, but its impact was fading within a decade. However, it was not repealed until 1967, when Soviet accomplishments in space were forcing Americans to examine the state of US science education. A similar law, passed in Arkansas through citizens’ initiative, survived until 1968, when in Epperson v Arkansas, the US Supreme Court ruled that the prohibition on teaching evolution was based on religion and therefore unconstitutional. As for the doctrine that creationism itself is religion, not science, and therefore should not be taught in public schools, that was not established in the US courts until McLean v Arkansas,1982 and at Supreme Court level Edwards v Aguillard, 1987, Justice Scalia dissenting.
The play does not even claim historical accuracy. It was written in 1951, and the preface (free download from here, p.11) states
Inherit the Wind is not history. The events which took place in Dayton, Tennessee, during a scorching July of 1925 are clearly the genesis of this play. It has, however, an exodus entirely of its own.
Only a handful of phrases have been taken from the actual transcript of the famous Scopes Trial.
…The collision of Brian and Darrow at Dayton was dramatic, but it was not a drama. Moreover, the issues of their conflict have acquired new dimension and meaning in the 30 years since they clashed at the Rhea County Courthouse. So Inherit the Wind does not pretend to be journalism. It is theatre. It is not 1925. The stage directions set the time as “Not long ago.” It might have been yesterday. It could be tomorrow.
“Could be tomorrow”, in 1951, when there had been no monkey trials since 1925? Clearly, the play is not about those events in Dayton, but a comment on the anti-intellectual mob rule of the McCarthy era. Despite this, the play, and the various film versions from 1960 onwards, have shaped public attitudes to the trial and, to my mind, lamentably coarsened debate.
And yet the exchanges between the Scopes trial prosecutors, and Clarence Darrow speaking for the defence, remain as topical as ever.
Darrow, the best remembered of the defence team, was not the ACLU’s choice, but they could not but follow Scopes in accepting his services, on this, the only occasion on which he offered them without a fee. He was an outspoken and abrasive agnostic, of whom the humanist Edwin Mims, Professor of English at Vanderbilt University, Nashville, Tennessee, and theological Modernist, commented, “When Clarence Darrow is put forth as the champion of the forces of enlightenment to fight the battle for scientific knowledge, one feels almost persuaded to become a Fundamentalist.” In his famous cross-examination of Bryan, Darrow comes over as a condescending bully. And yet any sympathy one might feel for Bryan quickly evaporates on reading the speech he had prepared for the court, but was prevented by defence manoeuvres from delivering. Bryan’s position presented defenders of science with a dilemma, to which I would dearly love to find a good resolution: one does not win over opponents by ridiculing their position and humiliating their champion, and yet what else is one to do when faced with ridiculous beliefs presented by a crowd-pleasing and truth-distorting blowhard?
This summer sees the 90th anniversary of the trial, widely regarded as an example of reason defeating obscurantism. My friend the historian geologist Michael Roberts argues, and I agree, that this popular view is damaging, as well as mistaken, and that the only long-term beneficiaries of the affair were the Flood Geology pseudoscientists, at the time of the trial itself no more than a fringe group within Young Earth creationism. What follows draws on Michael’s work, and on the trial transcript, the Pulitzer Prize winning account Summer for the Gods by the lawyer and historian Edward J. Larson, and other sources.
In the early 1920s, America’s churches were deeply divided between Modernists and Fundamentalists. Bryan, his once-promising political career now over, placed himself at the head of the Fundamentalist faction and its campaign to ban the teaching of evolution. The Governor of Tennessee was in favour of such a ban, but wisely recommended that the law should not specify a penalty. Even without one, it would make the State’s position sufficiently clear to its teachers, whereas if it could result in criminal prosecution, it would invite the controversy of a test case. That of course is exactly what happened.
As one might expect, some universities were highly critical of the law. The University of Tennessee itself hesitated to take a position, dependent as it was on state funding for its planned expansion, but Vanderbilt University, a private institution in Nashville, Tennessee, took a clear stand in favour of evolution. There was even a proposal to bar graduates of Tennessee State schools from Columbia University, leading school Superintendent White to suggest that Dayton found its own university, named after Bryan. This happened. The Bryan College Statement of Belief maintains “that the origin of man was by fiat of God in the act of creation as related in the Book of Genesis”, and since 2014 the teaching Faculty have been required to believe in the special creation of a literal historical Adam and Eve.
By 1925, when the Tennessee law was passed, the evidence for evolution was reasonably conclusive, but not yet as overwhelming as it is today. Molecular phylogeny, which places common ancestry beyond all reasonable doubt, was still decades in the future. Genetics was in its infancy, but Thomas Hunt Morgan was already working out how Mendelian inheritance, combined with mutation, could drive evolution, and these developments were referred to in Hunter’s Civic Biology, the standard text from which Scopes had taught. The fossil record was meagre by today’s standards, giving some appearance of substance to the creationist claim that Darwinism was based on extrapolation and conjecture, rather than observation. The record of human evolution was particularly scant, depending largely on Neanderthals, Heidelberg Man, and the now discredited Piltdown Man. All of these had cranial capacities not too different from modern humans, so it was still possible to argue that there was a “missing link” between us and what we choose to call lower animals, and the fact that the crude Piltdown forgery was able to survive in the scientific literature for several decades, albeit with heavy question marks, shows how underdeveloped physical anthropology was at that time. If we had to choose a date for when the “missing link” argument lost credibility, I would suggest February 1925, just a few months before the Scopes trial, when the first Australopithecine, the “Taung Child“, was described in the journal Nature. This find attracted major publicity, and the defence planned to use it in evidence.
Evolution was not the only topic that divided (and divides) the American churches. Of comparable significance was the challenge presented by the Higher Criticism, which argues that Genesis did not have a single author, but was the result of joining together two or more disparate and at times mutually contradictory texts. This view leaves room for regarding the Bible as inspired, but not for the traditional doctrine of word-for-word perfection and infallibility. Modernisers within the churches were willing to accept both evolution and textual criticism, and Fundamentalism, historically speaking, can be seen as a reaction to this Modernism.
Some legal features must be noticed, if we are to understand the trial in the context of its time. The statute specified what might or might not be taught in State universities; this would nowadays be regarded as violation of academic freedom. The constitutionality of the statute was at that time largely a matter of State, rather than Federal, law; it is now accepted that the State constitutions are fully subordinate to the freedoms guaranteed by the Federal constitution. And under the 1971 Lemon Test, a statute must not advance or inhibit religious practice (i.e. religious practice in general), and must serve a secular purpose. The Tennessee Supreme Court, in its judgement cited above, was using a much more restrictive test than this. We should also remember that Darrow and Bryan were personal friends, and had campaigned as allies on behalf of unionised labour.
Finally, and of the most enduring interest and importance, we have a conflict between two different concepts of democracy. The prosecution appealed repeatedly to the right of the majority, as the teachers’ paymasters, to specify the content of their teaching. Contrast this with what I might call the principle of liberal democracy, which guarantees freedom of expression, and when it comes to the content of education requires the public to defer to expert opinion.
The facts of the case were not in dispute. Scopes had taught from Hunter’s Civic Biology (the State’s own prescribed textbook!), and in so doing had taught about human evolution, and broken the law. So the case was not really about this, but about the status of the law itself. The defence case would be that Scopes should not be found guilty because what he did should not be called a crime.
Nor was the outcome difficult to predict. Judge Raulston was a devout Christian. Educated at a Methodist University, he was probably not himself a Fundamentalist, but was an elected official within a Fundamentalist-leaning state. In any case, he may very reasonably have thought that the broader issues should be decided by the higher courts, rather than at district level. So he could be expected to use all his ingenuity to block the defence’s claims.
The Tennessee statute, passed into law just one month after the Nature paper appeared, stated
That it shall be unlawful for any teacher in any of the Universities, Normals and all other public schools of the State which are supported in whole or in part by the public school funds of the State, to teach any theory that denies the Story of the Divine Creation of man as taught in the Bible, and to teach instead that man has descended from a lower order of animals. [Emphasis added]
Hence one prong of the defence strategy, as spelt out by defence attorney Malone:
The narrow purpose of the defense is to establish the innocence of the defendant Scopes. The broad purpose of the defense will be to prove that the Bible is a work of religious aspiration and rules of conduct which must be kept in the field of theology. [Emphasis added]
Malone is, in my view, one of the few protagonists whose reputation is enhanced by the trial. A Catholic but a divorce lawyer, himself remarried after divorce, he was a Modernist at a time when his Church was still undecided about evolution. His subsequent career involved serving as legal adviser to 20th Century Fox, and occasionally appearing in their films.
The other prong of the defence case would be to establish that the law was unconstitutional because unreasonable, since it flew in the face of the established scientific fact. So the trial involved both the main issues separating the theological Modernists from the Fundamentalists: evolution, and the proper use, by believers, of Scripture. Regarding the latter, the defence adopted the position later associated with the name of Stephen J Gould and his doctrine of “non-overlapping magisteria“. To interpret the Bible literally was to fail to understand it. Science and religion could not possibly be in conflict, because they were talking about different kinds of thing. Thus the defence hoped to call as witnesses both scientific experts, and leading Modernist theologians. Also, during jury selection, Darrow took care to ask each potential juryman what he thought about evolution. Clearly, many knew nothing about the subject, strengthening the case that they should hear evidence explaining it.
For the prosecution, Bryan tried to summon opposing scientific opinion, but could not find anyone of stature willing to testify against evolution. The prosecution therefore changed its tactics, aiming instead to restrict the trial to the simple fact of Scopes’s breach of the law. However, Bryan’s intended closing speech, which defence tactics (see below) prevented him from delivering, was to be a broadside against evolution using all the creationist devices of quote mining, misrepresentation of fact, and claims that evolution was unbiblical, atheistic, and morally corrosive.
The defence, as we have seen, was based entirely on discrediting the law, and indeed that was the reason why the ACLU had helped arrange for the case be brought in the first place. As a result, almost all the trial, spread over eight working days, was devoted to matters of law, not fact. Was the statute constitutional? Would it be deemed unconstitutional if it violated freedom of conscience, placed restrictions on how the Bible should be interpreted, or was contrary to established science, and what kinds of evidence could be introduced to decide these questions? Since the law was a matter for the judge alone, almost all the case was heard in the absence of the jury. In addition, numerous briefs supporting the defence were never heard at all, but simply placed on record for the benefit of the appeals courts.
At the outset, the defence argued that the indictment should be quashed because the law and the indictment based on it were defective, for a mixture of reasons. The State had a constitutional duty to cherish science, and science could not be taught without including evolution. The law was contrary to the State’s own establishment clause, by favouring a particular religion, and thereby violating freedom of conscience. In addition, it was so vague as to be meaningless, since it referred to what was thought in the Bible, but the Bible was open to numerous different interpretations.
Such arguments might seem strange to a reader from the United Kingdom, where Parliament is sovereign. But they are familiar in the United States, where both State and Federal Governments derive their legitimacy from written constitutions.
Hays for the defence argued that the law was intrinsically unreasonable, and therefore exceeded the policing rights of the state, as would a law against teaching that the Earth went round the Sun. “Evolution is as much a scientific fact as the Copernican theory.” The State could determine what subjects should be taught but could not reasonably demand that they be taught falsely.
Attorney General Stewart for the prosecution countered that the statute was about the proper use of state funds, and therefore within the State’s proper jurisdiction. The citizenry paid for their schools and therefore had a right to decide what those schools should teach. There was no violation of conscience, since Scopes was free to hold and advocate whatever opinion he chose, but that did not entitle him to propound evolution in opposition to state policy in the State’s own classrooms.
The defence had, as we shall see, decided on a strategy that would prevent lengthy closing statements, usually the highpoint of a criminal trial. And so Darrow presented his strongest arguments at this point. His speech, which took two hours to deliver, was considered the finest of his career. It was witnessed by over 200 newspaperman, as well as the judge and courtroom spectators. So millions of people knew what Darrow said, but not, ironically, the trial jury.
The speech was reprinted in full in the New York Times. Space, obviously, will not allow me to do the same, so I must make do with a bald summary, and a few quotations that may convey the flavour.
The Tennessee State constitution protected religious freedom, and therefore stated that “no preference shall be given by law to any religious establishment or mode of worship.” The law violated this principle, and was a law inhibiting learning. It established a specific religious standard because it gave specific status to the Bible, rather than any other sacred text. Evolution had been taught in Tennessee for years. Bryan “is responsible for this foolish, mischievous and wicked act… Nothing was heard of all that until the fundamentalists got into Tennessee.” As for the Bible, it contained different accounts of creation, making the law unworkable in its vagueness. It was a book of morals, not science. The law was unconstitutional because it violated the great Jeffersonian principle of freedom of conscience, vital to a civil society.
Here, we find today as brazen and as bold an attempt to destroy learning as was ever made in the middle ages. That is what was foisted on the people of this state, that it should be a crime in the state of Tennessee to teach any theory of the origin of man, except that contained in the divine account as recorded In the Bible. But the state of Tennessee under an honest and fair interpretation of the constitution has no more right to teach the Bible as the divine book than that the Koran is one, or the book of Mormons, or the book of Confucius, or the Budda, or the Essays of Emerson, or any one of the 10,000 books to which human souls have gone for consolation and aid in their troubles.
The Bible is a book primarily of religion and morals. It is not a book of science. Never was and was never meant to be. They thought the earth was created 4,004 years before the Christian Era. We know better. I doubt if there is a person in Tennessee who does not know better. They told it the best they knew. And while science may change all you may learn of chemistry, geometry and mathematics, there are no doubt certain primitive, elemental instincts in the organs of man that remain the same, he finds out what he can and yearns to know more and supplements his knowledge with hope and faith. That is the province of religion and I haven’t the slightest fault to find with it.
My friend the attorney-general [prosecuting] says that John Scopes knows what he is here for. Yes I know what he is here for, because the fundamentalists are after everyone that thinks. I know why he is here. I know he is here because ignorance and bigotry are rampant and it is a mighty strong combination, your honour.
The state by constitution is committed to the doctrine of education, committed to schools. It is committed to teaching and I assume when it is committed to teaching it is committed to teaching the truth.
Can [the legislature] say to the astronomer, you cannot turn your telescope upon the infinite planets and suns and stars that fill space, lest you find that the earth is not the center of the universe. Can it? It could – except for the work of Thomas Jefferson, which has been woven into every state constitution of the Union, and has stayed there like the flaming sword to protect the rights of man against ignorance and bigotry, and when it is permitted to overwhelm them, then we are taken in a sea of blood and ruin that all the miseries and tortures and carion of the middle ages would be as nothing.
If today you can take a thing like evolution and make it a crime to teach it in the public school, tomorrow you can make it a crime to teach it in the private schools, and the next year you can make it a crime to teach it to the hustings or in the church. At the next session you may ban books and the newspapers. Soon you may set Catholic against Protestant and Protestant against Protestant, and try to foist your own religion upon the minds of men. If you can do one you can do the other. Ignorance and fanaticism is ever busy and needs feeding. Always it is feeding and gloating for more. Today it is the public school teachers, tomorrow the private. The next day the preachers and the lecturers, the magazines, the books, the newspapers. After a while, your honor, it is the setting of man against man and creed against creed until with flying banners and beating drums we are marching backward to the glorious ages of the sixteenth century when bigots lighted fagots to burn the men who dared to bring any intelligence and enlightment and culture to the human mind.
The judge was having none of it. In a ruling slightly longer than Darrow’s speech, he gave his opinion that the law was perfectly clear, and legitimate in its scope. The offence consisted in teaching that man was descended from a lower order of animals, and the references to evolution and the Bible merely provided additional context. Later on in the trial, he was to rule on more or less the same grounds that evidence concerning evolution, and about different ways in which the Bible could be interpreted, were beside the point.
The judge no doubt intended his point by point rebuttal of the motion to quash to be dramatic. Unfortunately, before he delivered his ruling, it had already been published in the newspapers. He was furious and ordered the assembled pressmen to trace the source of the leak. They had little difficulty. The source was Judge Raulston himself. One reporter had asked him, with affected casualness, whether the case would be resuming directly after he delivered his opinion, and he had said that it would. But if he had accepted the motion to quash, there would have been no case left to resume.
The defence next quoted the Governor himself as having said that the law was consistent with the existing States textbooks, would not put Tennessee’s teachers in any jeopardy, and would probably never be applied. In response, the judge quite correctly pointed out that under the American doctrine of separation of powers, the Governor as head of the executive branch had no right to impose his own interpretation on the law, this being the role of the judiciary. He also ruled that expert evidence concerning evolution, and about different ways in which the Bible could be interpreted, were irrelevant and inadmissible, but allowed the defence to place such evidence in the trial record for the benefit of the appeals courts.
In my next post, I will describe this inadmissible evidence, Darrow’s famous dialogue with Bryan, Bryan’s intended closing speech and why it was not delivered at the trial (although Bryan did deliver two very similar speeches in the days immediately following), how the case was settled, and subsequent legal battles. I will also give my own view on who won, who lost, the extraordinary errors of judgement displayed by both the main protagonists, and the implications for us today.
1] The trial transcript and related documents are freely available as PDF photocopy (readable but not suitable for cut-and-paste, although PDF readers such as Nuance can convert much of it to edit-ready MSWord). In addition to these, and Michael’s account, I have used that given by the constitutional lawyer Douglas Linder (Professor at University of Missouri Kansas City Law School) here. . The fullest account, however, is by the lawyer and historian Edward J. Larson, whose Summer for the Gods earned a Pulitzer Prize. I have also used other sources, such as Ronald Numbers’ authoritative study, The Creationists; Numbers has also posted much of his research on line here, as part of the Counterbalance science in context project. I acknowledge special help from Alastair Arthur, of Glasgow University Library Services.
2] Full text at http://darrow.law.umn.edu/documents/Scopes%202nd%20day.pdf p. 74 on. Here, I have for ease of reading omitted ellipses, and added some half dozen words for continuity.
Dayton courthouse courtesy Michael Roberts. Darrow by Mobius, public domain. Taung Child image by Didier Descouens via Wikipedia. This piece appeared earlier in 3 Quarks Daily.
(Reblog of Terry Mortenson concedes: ‘Stone Age’ tools are a problem for YEC, Age of Rocks) Lava flows across Antrim? Blame Noah’s Flood. Palaeosols in between them? Noah’s Flood again. Moving continents? Obviously the result of Noah’s Flood. All those poor extinct dinosaurs (the ones that weren’t later exterminated by Nimrod the Mighty Hunter) – drowned in Noah’s Flood. And radiometric dates proving, by any sane standard, an ancient Earth? You guessed it; they don’t take account of the radiation associated with Noah’s Flood.
And now, with breathtaking disdain for reality, a Creationist explanation for the Palaeolithic toolmaker’s rubble that covers so much of Africa (but nowhere else). All produced by colliding rocks, during Noah’s Flood.
Wait a bit and we’ll be told that cratering on the Moon, Mars, and Mercury is somehow caused by Noah’s Flood. Come to think of it, we don’t even need to wait. There’s one school of Creationist thought, if you’ll forgive the oxymoron, the one behind Noah’s Ark Zoo Farm near Bristol, that says exactly that.
Answers in Genesis generally does well not to acknowledge its best critics, because doing so exposes their audience to the fact that theirs is a ministry rooted in pseudoscience, which is ultimately damaging to the cause of Christ. If we abhor the truth as it pertains to the natural world, how are we to persuade anyone that we hold the keys to God’s kingdom?
When AiG does respond, typically it is prefaced with caveats highlighting the ‘naturalistic’, ‘atheistic’, or ‘evolutionary’ assumptions that motivate their attackers. This strategy is effective in dismissing those like Richard Dawkins, who are not shy about such convictions, or Bill Nye, who—though less antagonistic—is still not a confessing Christian. However, as Terry Mortenson demonstrated yesterday, AiG cannot entirely ignore pleas from within the church, despite that it simultaneously informs their readers that most Christians—especially those holding advanced degrees in theology or the natural sciences—also describe creationist’s efforts as bad…
View original post 2,224 more words
Update: Primate’s Progress it is.
And now for something a great deal less serious.
I originally planned to concentrate on scientific topics, especially the quirks of evolution, so I called this blog “Eat Your Brains Out”. I was referring in particular to the sea squirt. A sea squirt is a tunicate, a member of the group most closely related to vertebrates (that’s you and me and frogs and fishes), but you wouldn’t think so to look at it. As I wrote the story, it starts out as a free-swimming larva, clearly related to our tadpole ancestors, but when it grows up it just sticks its head on a rock and turns into a couple of slimy tubes and reabsorbs its juvenile nervous system because it doesn’t need it any more. Nice story but, as a well-informed reader pointed out, it’s more a matter of rearranging than reabsorbing. Besides, I suspect that more people know about Zombie Apocalypse than about the metamorphosis of sea squirts. And in any case, I’ve found myself writing about all kinds of things, such as politics, education, and freedom of speech, not just about science. Time for a new title.
So, after watching the final episode of BBC’s Monkey Planet (“how primates are individuals with a sense of self and why brainpower is essential to primate survival”), I decided to assert my sense of self and advertise my brainpower by renaming my blog The Pensive Primate. But then I discovered a company selling what it calls Pensive Primate gifts, such as mugs and T-shirts with pictures of orangutans on them, so I settled for Primate’s Progress instead. However, I have mixed feelings about the word “progress”. It makes me sound little bit like (perhaps I am a little bit like) a naive optimist left over from an earlier century. More seriously, it suggests a common misconception about evolution, which is that it is somehow always Onwards and Upwards.
Further searching showed that the label “Pensive Primate” has actually been used many times by photographers and artists, and as far as I can see it is not a trademark. It follows that I can use it too if I want to. After all, there’s no real risk that this blog will be mistaken for a multi-million marketing enterprise.
So now I have to decide. Which is it going to be, The Pensive Primate or Primate’s Progress?
Image: BBC web site
In an earlier post, I said that the right way to undermine creationism is to promote appreciation of the science of evolution, by presenting it in ways that are engaging, enjoyable, and above all personal. In this post, I review two more books that succeed in doing this; Alice Roberts‘ The Incredible Unlikeliness of Being and Jonathan Tweet‘s Grandmother Fish.
Grandmother Fish is a book like no other I have seen. It is an introduction to evolution, for adults to read to their pre-school children. It is also much more than that, and comes with well-earned commendations from Stephen Pinker, David Sloan Wilson, and Daniel Dennett.
We start with a delightfully drawn Grandmother Fish, who lived a long, long, long, long, long time ago and could wiggle and swim fast and had jaws to chomp with. At once, this is made personally relevant: “Can you wiggle? … Can you chomp?” We proceed by way of Grandmother Reptile, Grandmother Mammal and Grandmother Ape, to Grandmother Human, who lived a long time ago, could walk on two feet and talk and tell stories, and whose many different grandchildren
could wiggle and chomp and crawl and breathe and squeak and cuddle and grab and hoot and walk and talk, and I see one of them … right here!
Each stage has its own little phylogenetic tree, with the various descendants of each successive “grandmother” shown as each other’s cousins, and there is an overall tree, covering all living things, that anyone (of any age) will find interesting to browse on. Finally, after some 20 pages of simple text and lavish illustration, there are around 4 pages of more detailed information, directed at the adult reading the book, but to which I expect children to return, as they mature, remembering the book with affection, as they surely will, years or even decades later.
So here we have nested families, family resemblance, and the development of more and more specific and complex features. And any adult, or indeed any alert child, will readily extend the discussion. Was there a grandmother cat, whose grandchildren include lions and tigers and pussy-cats, and how was she related to grandmother carnivore? Where do fossils fit in? (The tree shown includes pterodactyls, dinosaurs, and early birds.) And the most common arguments against evolution, from “only a theory” to “where are the intermediate forms?” to “if evolution is true, why are there still monkeys?” will stand immediately revealed as the nonsense they are. Indeed, one of the few statements in the endnotes that I disagree with is that “Evolution by natural selection is very difficult to understand because it doesn’t make intuitive sense.” It will, in my opinion, make perfect sense to a child who has met so clear an exposition early on, and who will therefore find it much easier to understand intuitively than, say, Noah’s Ark.
Back story: this project was crowdfunded on FaceBook, on the basis of some initial sketches and text. The author professes a long-standing interest in evolution, but his career hitherto has been elsewhere, in computer games (he was lead designer on the 3rd edition of Dungeons and Dragons). However, he has had expert advice from many people, including Eric Meikle, Education Director at the [US] National Center for Science Education.
Disclosure: I have corresponded with the author who tells me I will be thanked on the book’s website. Review based on initial draft + correspondence with author. I will be buying this book for my grandchildren as soon as it becomes available.
The Incredible Unlikeliness of Being, despite (because of?) coming from an established author and presenter, is as personal as could be. It starts with Alice Roberts’ emotional response to becoming a mother, and the incredibly unlikely being is the reader. The subject matter is (mainly) the development of the human embryo, and that developing embryo is not some third party abstraction, but you. And so evolution is also about you, as example after example throughout the book makes clear:
It’s about your evolutionary heritage, and it is about your own embryological development, when you grew in changed, part of you folding like origami, until you are shaped like a human.… This is the best creation story, because it is true.… This scientific story, pierced together from many different sources of evidence, is more extraordinary, more bizarre, more beautiful, than any creation myth we could have dreamt up.
Alice Roberts is Professor of Public Engagement in Science at the University of Birmingham, and one of the new generation of writers and TV presenters who in the UK fill much the same role as Bill Nye and Neil deGrassie Tyson in the US. She is by training a doctor and anatomist, and much of her own research has involved forensic examination of pre-human hominin skeletons, the coldest of “cold cases”. This background shows up clearly in her detailed descriptions of your developing structures, and she shares with us her emotions about coming face-to-face (in one case literally) with her own anatomy, as when, after x-ray tomography, she was given a replica of her own skull.
The unlikeliness is not just the obvious unlikeliness of your two particular parents meeting, of that one egg becoming fertilised, and of that one sperm out of the enormous number available on being successful. Nor even of the improbability of your parents in turn having come into existence, and so on. Behind all this, and multiplying all those improbabilities, is the meandering history of our evolution:
The more I delve into the structure and workings of the human body, the more I realise what a cobbled-together hodge-podge of bits and pieces this thing we inhabit really is. It is brilliant, but it is also flawed. Our evolutionary history is woven into our embryological development and even adult anatomy in surprising ways; many of our body’s flaws can only understood in an evolutionary context.
We start with a history of ideas, and here it struck me as remarkable how long it took for it to be generally recognised that both parents contribute to the form of their offspring, despite the obvious evidence from physical resemblances. Leeuwenhoek with his microscope first observing sperm, the much later discovery of the mammalian ovum, a comical (in hindsight) controversy between “spermists” and “ovists”, the puzzle, insoluble even in principle until the advent of genetics, of how both parents could contribute to what we now call the information content of their offspring, and the further conundrum, unsolved until DNA was identified as the genetic material, of the material means by which they did so.
Most of the book is concerned with the complex process that leads from first release of the ovum, through fertilisation, implantation, and the many subsequent stages of development, through to birth. This story is inextricably intertwined with the story of your evolution, and I can only pick out a few of the most salient points from a wealth of fascinating detail.
There are, of course, vestigial or discarded organs. In your second week of development, when you were not much more than a couple of layers of cells, you generated a yolk sac, homologous with the yolk sac of fish, amphibians, reptiles, and even those mammals (the platypus and the spiny anteater) that lay eggs. The difference is that in these the yolk sac is filled with the nourishment that will sustain the growing animal until its birth, whereas in placental mammals like us, it has been without function for the past 90 million years or so. Nonetheless, the recipe for making it has never been deleted from your assembly instructions.
At an early stage, it is very difficult to distinguish the embryo of a mammal (that includes you, of course) from that of a fish; a little later it is still difficult to distinguish it from a reptile or a bird, and different mammalian embryos continue to resemble each other for even longer. For a while, it was suggested that this is because you were retracing your evolutionary history, but we now know that this idea is based on a mistaken model of evolution. You are not more highly evolved, than, say, a chicken; you have just evolved in a different direction. The earliest stages of development are shared with fish, later stages with reptiles and birds, and later stages yet only with mammals and eventually only with our fellow apes. Thus we do not, strictly speaking, recapitulate our evolution from a fish, nor should we, since the present-day fish is as remote as you are from your last common ancestor with a halibut, but we do recapitulate shared development until the parting of the ways. The new science of “evo-devo” is now beginning to take this story down to the most fundamental level, identifying the molecular basis for the parts of the construction plan that you share with a fish, and the parts, activated later, that you do not.
The cartilage base of human skull resembles that of other mammals. It is only later, when this is being transformed to bone, that it acquires its specifically human form, with the enlarged dome required to house the brain towering above the rest of the head.
Working down from the head takes us to the larynx, and the unanswered question of the origin of human speech. Here the problem is that the really important working parts – the larynx itself, its associated muscles, and, above all, the tongue – are soft tissues and leave no trace in the fossil record. The position of the larynx lower in the throat, compared with other mammals, may be no more than an accidental consequence of the way our oversized brainboxes sit on top of our spinal column.
The origin of the larynx leads us to the most striking embryological evidence for evolution, namely the direct resemblance between the branchial (gill) bars of fish, and the related structures found, early in development, in terrestrial vertebrates. Then comparative embryology allows us to map our own organs against their fishy counterparts, and to explain some of the more absurd features of our own anatomy.
Our fishy origins are clearest early in development. By week four, the bundle of cells on its way to becoming you has separated into three separate layers, a tube within a tube within a tube. On the outside, ectoderm, which will give rise to your skin; on the inside, endoderm, which will give rise to your digestive tract, from one end to the other, and in between mesoderm, giving rise to a variety of structures. By week five, we can see what will become the backbone, the eye, and the branchial bars in the neck. Each branchial bar has ectoderm on the outside, endoderm inside, and in between a mixture of cells, some from mesoderm and some from neural crest. This in-between layer will develop into a cartilage bar and muscles, and each bar will develop an artery and a nerve.
Land animals and fish have shared much the same developmental instruction manual until this point, but now they begin to diverge. In fish, the branchial arteries accept blood directly from the heart, and the cartilage forms the gill arches. In land animals, development is far more complex. One set of gill muscles becomes larynx muscles, and a nerve that leads to it runs down into the chest, before making its way back up to the top of the throat. Why so? Because the blood vessels that, in fish, run directly between the heart and the gills have become, in land animals, the aorta and main arteries leading from it. And as a consequence, the recurrent laryngeal nerve, as it is called, is trapped beneath the aortic arch when the heart moves downwards, as it does in land animals but not in fishes, and forced to take this convoluted path. Bad design, but an unavoidable consequence of evolutionary history. A creationist with whom I once discussed this suggested that this really was a good design, because it protects the nerve from damage. Tell that to a giraffe.
The first branchial arch gives rise to bones that are part of the jaw joint in reptiles, but in mammals have shifted and shrunk and become two of the bones of the inner ear. And yes, there is an intermediate form, an early mammal with two jaw joints, the outer one thus being made free to move closer to the ear to improve resonance, and, ultimately, to detach itself. Gill flap muscles in the fish end up as face muscles in primates including us, and so on. The cleft between the first and second branchial arch gives rise, in us, to our ears, and to the tubes that connect the middle ear to the throat, thus enabling pressure to equalise.
Descending to the molecular level, these developments are orchestrated by a set of control genes, prominent among them the so-called “homeobox” or Hoxgenes, first discovered in fruit flies, where they regulate the formation of the segments of head, thorax, and abdomen. Similar genes are found in every segmented animal, including us (if you don’t think you’re segmented, think of your backbone and ribs). This arrangement must be very ancient, since your last common ancestor with a fruit fly was some 800,000,000 years ago, but has undergone elaboration. The fruitfly has 8 Hox genes, lined up in a row, that come into play one after the other. In the lancelet, this has been expanded to 14. At some stage between the lancelet and jawed fishes, the entire genome seems to have doubled and redoubled, so that you have four sets of Hox genes, each on a different chromosome.
Some aspects of this regulatory system are much more flexible than others. All land vertebrates have a spine with the same basic sections: neck, chest, lower back, sacrum, and tail. All mammals have just seven neck vertebrae, whereas the number of tail vertebrae is highly variable, being up to 49 in one species of porpoise, which flexes its tail to swim, while our tail, or coccyx, has only 3 to 5 fused together. This tail can be considered as a vestigial organ, since it is a mere relic of that sported by our monkey-like ancestors, but like many so-called vestigial organs it continues to earn its keep, in this case by acting as an anchor for muscles. Our lower backs have one more vertebra then our chimp cousins, and are less securely held in place, developments thought to be related to our habitual walking on two feet
Relevant to Professor Roberts’ own anatomical interests, although less directly so to the question of embryological development, is the detailed history of our limbs. This indicates us to have been truly bipedal as long ago as 3.2 million years ago (Lucy), while long legs at 1.5 million years ago (Narikotome boy) suggest adaptation for running. In popular imagination, we learned to stand upright as we evolved away from knuckle-walking ancestors, but the reverse may be the case. Monkeys, like us, have feet far harder and less flexible than those of modern non-human apes, and Prof Roberts speculates that our ancestors were tree walkers. If so, it is the apes, with their prehensile toes, rather than us, who have diverged from the form of our common ancestor.
But once we started walking on the ground, that change in behaviour, which could occur within a group in a single generation, would have suddenly generated a new set of selection pressures in favour of long distance walking and running. This is an activity for which we are superbly adapted, even though only a few groups, such as the Tarahumara in Mexico, still regularly practice it.
The final Chapter reviews our present understanding, and considers our place in nature. Development is controlled, more or less, by DNA, including control genes as well as directly expressed genes. It is not, as Haeckel thought, a true recapitulation, but shows clear echoes of earlier stages – segments, gills, fish hearts, the lancelet brain. Our developmental biology is, to use one of Prof Roberts’ many memorable metaphors, a palimpsest.
Similar environmental pressures can give rise to similar adaptations, so that the mammalian ear with its three tiny bones has evolved at least four times in different lineages, while, as hinted above, different ways of moving around including bipedalism may have arisen more than once among our ancestors and their close cousins. But nonetheless, evolution remains unpredictable, if only because changes in the environment are unpredictable. One such change was that triggered by the asteroid that did for the (non-avian) dinosaurs. Selection acts without foresight, and without that asteroid, we would not have had humans (for what it’s worth, my own view is that we would have had the intelligent descendants of the velociraptors instead).
Evolution takes place in context, and that context, for a species capable of learning from each other, includes a technology. An innovation in toolmaking could have spread through a group of our ancestors in a single generation, triggering a new set of selection pressures that moulded their hands and bodies to a new set of tasks. We speak of the survival of the fittest, but fitness here refers to the cultural, as well as the natural, environment. And we are more influenced in our lives, and our evolution, by our own culture and its artefacts than any other species.
The book concludes with reflections on our similarities (profound) and differences (striking, yet perhaps more quantitative than qualitative) from other species, our contingent and transitory nature, and our uniqueness both as species and, returning to the starting point, individuals.
There are numerous drawings (Prof Roberts is an award-winning artist), and an extensive bibliography.
A few detailed comments. Prof Roberts shows, early on, a series of drawings copied from Haeckel. Connoisseurs of creationism will recognise this as a deliberate provocation, since creationist writers repeatedly point to alleged shortcomings in these, as reason to ignore the whole of developmental science. Lancelets are shown as sister group to vertebrates; in fact, we are closer to tunicates (the subphylum that includes sea squirts) than we are to lancelets, although tunicates only acquired their sessile habit after we and they had gone our separate ways (Prof Roberts tells me that this will be corrected in later editions. I occasionally found the layout of diagrams and their explanations rather awkward. This may be an inherent limitation of the e-book format that I was using.
Disclosure: this review is of the first Kindle edition, personal purchase.
These reviews first appeared here, on 3 Quarks Daily
If there really were lots of people, not just Noah’s family, and they really were spread out over Africa, and if they really were making tools from some 2.6 million years before present, and if they were profligate throwaways when it came to flint flakes, then a little arithmetic shows that there ought to be trillions (yes, millions of millions) of discarded tool bits all over Africa. And there are.
Earlier, I blogged about time as interval at Siccar Point, and time as process where the lavas of the Giants Causeway were weathered between outflows. Now (see below, reblogged from Naturalis Historia) I can add time as the accumulation of junk. Time shallow by geological standards, but very deep indeed compared with all of human history, or with the imaginings of the author(s) of Genesis. And I don’t think even Ken Ham can talk his way out of this one.
And this week sees the resolution of another paradox: the oldest tools known date to some 2.6 million years before present (Mybp), but the oldest clearly hominin remains were at 2.4 Mybp. So do we have to infer that australopithecines made tools? Not necessarily, since (see here, and references therein) we now have a decidedly hominin-looking jaw at 2.8 Mybp.
There may be other implications for our ancestry. Jaw bones are the best preserved of all skeletal remains, but on their own they tell us little about what most interests us – the size of the brain case. However, where one fragment was found there may be others, and we can only await further developments.
Trillions of stone artifacts cover the surface of the African continent. The product of the manufacturing of stone tools by hunters and gathers over long periods of time, these stone artifacts literally carpet the ground in some places in Egypt and Libya.
Just how much Stone-Age produced rock is strewn across the African continent?
Imagine a volume of rock equivalent to 42-84 million Great Pyramids of Giza.
The “million” isn’t a typo. That number sounds absolutely fantastic, doesn’t it? Let’s take a look at how these numbers were derived.
The results of a study just published (see references below) shows how incredibly dense stone artifacts can be in some places in Africa. Working in a remote location in southern Libya, researchers took surveys from hundreds of one or two-meter square plots. From the tens of thousands of artifacts found in them, they estimated a minimum density of 250,000 stone artifacts…
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Until yesterday, it may just have been possible to accept the claim by Glasgow’s Centre for Intelligent Design (C4ID) that the view it promotes differs from old-fashioned creationism. Not any more. Dr Noble, the Director, writing for C4ID, has used a whole range of traditional creationist arguments in a full-blooded attack on the Scottish Secular Society’s petition, currently before the Scottish Parliament, in which the Society requests
official guidance to bar the presentation in Scottish publicly funded schools of separate creation and of Young Earth doctrines as viable alternatives to the established science of evolution, common descent, and deep time.
Predictably, the C4ID submission  attempts to disguise the fact that “Intelligent Design” is nothing more than a blend of creationism and obfuscation. This has famously been established in court (Kitzmiller vs Dover School Board), and elsewhere. Most relevant to the present petition is the statement to this effect from the Association for Science Education, the UK-wide association of science teachers at all levels, and the UK’s largest teaching subject organisation.
“Macro-evolution … unobserved and speculative”
More interestingly, the C4ID submission illustrates precisely the disinformation that we seek to guard our children against, by itself embracing creationism. It does this by driving a wedge between “micro-evolution” and “macro-evolution,” and admitting that the former of these occurs, while describing the latter. Such dismissal of macro-evolution can have only one implication, the separate creationism to which we are objecting, and the denial of the results of almost two centuries of careful scientific observation. As the submission puts it:
Few people, including the most ardent religious believers, deny that evolution in the form of adaptation is an empirically observed phenomenon. This can be described as ‘micro-evolution’ and it is the sort of variation, in, for example, the beak sizes of finches that Darwin observed in the Galapagos Islands. However, those findings say nothing about how finches arose in the first place. The speculation that evolutionary processes can explain the origin as opposed to the distribution of finches can be referred to as ‘macro-evolution’. This is an unobserved and speculative feature of the theory of evolution. It is therefore inaccurate and confusing to refer simply to ‘evolution’ without clarifying which aspect of the theory is being dealt with.
Some minor points: C4ID mention religion; we did not. C4ID, like all creationists, cannot resist referring back to Darwin, much as some demented opponent of atomic theory might keep on referring back to Dalton. But the main point regard evolution: if macro-evolution didn’t happen, the only alternative is separate creation.
As a commentator (David Bell at FB Secular Scotland) points out, Macro and Micro evolution are the ID version of Ken Ham’s “historical science” and “observable science”.
In a sense, of course, macro-evolution is unobserved, but only in much the sense that the Ice Ages are unobserved. Macro-evolution has not been directly observed over the 3000 or so years of recorded scientific observation because it takes more time than that, and the Ice Ages have not been directly observed by scientists because they happened too early, but in both these examples the evidence is incontrovertible.
Regarding the Ice Ages, we have evidence such as erratic boulders transported by glaciers, scratches on rocks, and massive moraines left behind, as far south as Lueneberg Heath in Germany and Minnesota in America. Regarding macro-evolution, we have, to choose just one well-explored example out of the enormous range available, the evolution of whales from terrestrial hoofed mammals. Here we have two completely independent lines of evidence ; a fossil record showing at least 10 well-defined intermediate forms, either on or close to the ancestral line leading to modern whales and porpoises, and molecular phylogenies (no different in principle from the DNA evidence used every day in our courts to establish family relationships) that show whales as first cousins to a hippopotamus and second cousins to a cow (for a general reader level open-access review, see here).
If the evolution of the blue whale, purely aquatic and the largest animal ever known on this planet, from a small terrestrial wader, does not count as macro-evolution, what does? If this kind of evidence does not remove macro-evolution from the domain of the “unobserved and speculative”, what would?
Or I could have chosen human evolution, where some 20 distinct hominin species have been identified, with steady progression in bipedality, cranial capacity, dentition, and all the other features that distinguish us from apes .
Or birds from non-avian dinosaurs, with the step-by-step evolution of feathers and then of flight. Or amphibia from lobefish. Or sheep and goats. Or dogs, bears, walrus and weasels from a common ancestral carnivore. All beautifully documented in the fossil record, and now supported by molecular phylogenies, along with numerous other examples. There is no lack of well written books explaining these things in highly accessible language , a major website has an entire section devoted to such transitions, and if C4ID are really ignorant of these evolutionary facts, the ignorance is self-imposed.
Having once placed C4ID in its rightful place in the evolution of delusion, their other arguments fall readily into place. We have the usual complaint that we want to put all talk of creationism off-limits, when we explicitly state that we intend no limitation on the discussion of ideas; merely on the misrepresentation of facts. We have the usual claim that an intelligence (or Intelligence) is required to generate new information, as if otherwise information were some kind of conserved entity like energy. We have the claim that all DNA has been shown to be functional – a travesty of even the most extravagant claims made in the current “junk DNA” controversy. We have the vulgar error that the forces driving evolution are random, whereas in fact organisms are sculpted by natural selection. We have the usual inversion of burden of proof, where the unexplained is deemed unexplainable, while those who seek natural explanations for what we do not yet understand are called closed minded. We have the argument that since natural selection sometimes works by elimination (and indeed it does), it can never really work by addition. We even have (was nothing learnt from the debacle at Dover?) irreducible complexity.
Since this is the high-class version of creationism, we also have the lofty argument that, in C4ID’s words,
The neo-Darwinian position that life and the universe, including conscious thought, are the result of blind and purposeless processes gives no reason to believe that our investigations and conclusions have any validity or truth. Students should be aware of this.
This is absurd, as I like many others have said before. If our investigations and conclusions had lacked validity or truth, we would simply not have survived. Indeed, there is now a flourishing if controversial subdiscipline that considers our minds, with both their strengths and weaknesses, as the products of natural selection. Given this, C4ID’s claim that “Students should be aware of this,” when “this” is a doctrine residing only on the philosophical fringe, is breathtaking in its arrogance. (There are of course environments, such as creationist universities and seminaries, where survival is more likely if one’s conclusions lack validity and truth, but the cradle of mankind was not one of them.)
Finally, the C4ID submission accuses the petition, which I helped draft, of making an unwarranted prior assumption of philosophical naturalism; here the author, Doctor Noble, is echoing the ideas of his mentor, Phillip Johnson. As it happens, my one and only contribution to professional-level discussions on the philosophy of science is to prove that in reality we neither need nor use any such assumption. Naturalistic explanations stand or fall in science, as in all human endeavours, on their merits; we use them because they work. Our reason for rejecting non-natural (supernatural? praeternatural? unnatural?) explanations is that they cut no ice. In every case studied, their predictions have turned out to be wrong, or unnecessary, or ambiguous to the point of utter uselessness, and the sorry history of Intelligent design research merely bears this out.
After C4ID, Answers in Genesis comes as comic relief, even if the gag lines are rather predictable. Evolution is a religion and an attack on Christianity (never mind that the spokesperson for BCSE, which supports the petition, is an Anglican priest; as far as AiG is concerned, he’s the wrong kind of Christian). Historical science is in a separate category because it deals with the past and is therefore not testable (what does AiG think geologists and palaeontologists do all day?) Evolutionary naturalism is atheism. Secularists (meaning, I imagine, everyone who does not use Genesis as a geology textbook) are in rebellion against God. Reaching these profound new conclusions the work of any one individual, butrequired the help of AiG‘s research team. And only one thing spoils the joke for me – the knowledge that People with a Mission Ministries, who promote AiG‘s materials, are made welcome in schools throughout Scotland.
Which is why the petition is needed in the first place.
 I have made these links “no-follow”, to avoid boosting the site’s ratings.
 Full text at http://www.scottish.parliament.uk/S4_PublicPetitionsCommittee/General%20Documents/PE1530_A_Centre_for_Intelligent_Design_UK_10.10.14.pdf (warning: extreme boredom alert).
 Some would say “other apes”, since if apes are a clade – a complete set of descendants from some common ancestor – then we are part of it.
 For the fossil record and its tie-in with phylogeny, my personal favourite here is Don Prothero’s Evolution: What the Fossils Say and Why It Matters.
 I refer of course to evolutionary psychology. Here my own position is that all psychology is evolutionary, since I have no other way of explaining the existence of our atavistic shortcomings.