Pharyngula

PZ Myers at Glasgow Sceptics in the Pub, The Crystal Palace
by KG

The Crystal Palace, where the Glasgow Sceptics in the Pub hosted PZ, is a bit of a disappointment as far as appearances go, being neither crystalline nor palatial, just an over-sized pub. However, the upstairs meeting room is a good size, and a crowd of perhaps 200 filled it but fitted in comfortably for his talk. Most were young, a majority but not a huge majority male, and at least one doing his bit to mitigate global warming with a fine piratical hat. I shared a table with two Edinburgh skeptics, and chatted after the talk with one of the few attendees older than me, who had travelled up from Manchester.

The meeting room has an overhead projector, but unsuccessful attempts to get this to work, involving a stepladder and a variety of electrical leads, caused a 45 minute delay. In the end, the Sceptics abandoned it, and propped a projector up near the floor, so PZ was obliged to give his talk on developmental evidence for evolution – title “The Pharyngula” – using slides that were slightly wonky and overflowed the screen at the edges. He triumphantly overcame this handicap, giving a succinct but vivid and illuminating history of developmental biology and its relation to evolutionary theory.

PZ first noted that the study of development provides, as Charles Darwin noted and as remains the case, perhaps the clearest evidence for evolution of any branch of biology. He first answered the last and key part of the first of the ten questions distributed in advance by Uncommon Descent urging their fellow-idiots to attend the talk:

1) In light of the Darwinian evolutionary paradigm, can you account for the observation that the eggs of the five classes of vertebrate (i.e. fish, amphibians, reptiles, birds and mammals) begin markedly different from each other? While the cleavage patterns in four of the five classes show some general similarities, the pattern in mammals is very different. Furthermore, in the gastrulation stage, a fish is very different from an amphibian, while both are starkly different from reptiles, birds and mammals, which are somewhat similar to each other. Doesn’t Darwinism predict a pattern wherein the earliest stages are the most similar and the later stages are the most different? [emphasis added]

The answer is, of course: “No.”, thus disposing of the rest of this question and the remaining nine, all of which were premised on this ignorant misconception.

IDiotic questions thus disposed of, PZ turned to more interesting topics. The physicist Ernest Rutherford claimed that “All science is either physics or stamp-collecting” – this is “full of shit”, indicating Rutherford’s ignorance of biology, but also “kind of right” – there is a form of stamp-collecting science that is just a cataloging of facts, and this is insufficient: explanation of the facts is key, and the history of science must also be appreciated. I for one had not realized that the view expressed in the slogan associated with Haeckel: “Ontogeny recapitulates phylogeny”, has pre-evolutionary roots in the idea, formulated by C.G. Carus in 1835, that the similarity of animal embryos at early stages is due to organisms climbing the “great ladder of life”, from “inferior” (starting with jellyfish) to “superior” (culminating, of course, in humans). The obsolete term for Downs’ Syndrome, “mongolism”, reflects the racist extension of this view to differences among humans.

Carus’ view was opposed by Karl Ernst von Baer, probably the “greatest embryologist of all time”, although cranky, snobbish and brutal. PZ’s quip: “I’m not as brilliant as von Baer, but I can at least emulate that part!” was appreciatively received. Von Baer was not an evolutionist, and did not become one even after Darwin published the Origin. He gave a very different explanation from the ladder: early embryos express “general characters”. He made a comparison to sculpting: the sculptor first builds a rough outline of the required form, then adds details. This view of development is still valid; Darwin agreed with it in general, but noted that there are also significant early differences, especially in larval characters: we must look deep.

Haeckel was responsible for a reinvigoration of recapitulation theory, giving an evolutionary interpretation of the “ladder”: development as a process of repeating evolutionary history. Darwin made a serious mistake in partially accepting this, due to his ignorance of the mechanisms of heredity and belief in the inheritance of acquired characteristics: he thought that every embryo stacked new features on top of previous developmental history, as characteristics acquired in adulthood were assimilated by “pangenesis”. Haeckel exaggerated embryological similarities and at one point – his “somites” diagram (not the one most often criticized by creationists), actually cheated, for which he was severely reprimanded by his university.

The next part of the talk dealt with Hox genes, which are partially responsible for the spatial patterning of the developing body. These genes are clumped together in the genome, and their order can be (approximately) linearly mapped onto positions in the body. The same molecular probes work in a lot of different animals, and genes are often ordered in the same way. There are differences between vertebrate embryos at the pharyngula stage – but most are distortions due to the presence or absence of yolk. At the earliest stages – eggs – there are big differences; there is convergence at the pharyngula stage, divergence from there: this is the so-called “developmental hourglass”. The “neck ” of the hourglass, the phylotypic stage, represents the peak of global molecular interactions. After this, interaction becomes more local. How narrow the “neck” is, is a focus of current research.

Finally, PZ turned to the exposure and analysis of creationist lies. Jonathan Wells, the “most contemptible liar in creationism today” (surely a hotly contested title!) falsely claims that evolution is built on Haeckel’s recapitulation theory – which was, in fact, discarded in the late 19th century as the facts of genetics began to be elucidated. Wells selectively quotes a paper from BioScience 1976 by William (Bill) Ballard – a fish embryologist who named the pharyngula, and one of PZ’s scientific heroes – to support this, but as ever when creationists quote using ellipses, there’s something important missed out, and Ballard did not make the claim Wells attributes to him. The Discovery Institute and other creationist organizations aim to make you more stupid: Wells, bizarrely, grades text books with a “D” if they use photographs rather than drawings – because these show clearly that the facts of development unequivocally support evolutionary explanations.

The overall lesson of the talk: evidence is central, but don’t neglect theory. Good theories are predictive and useful, diligent towards the evidence. Bad theories disregard the evidence and emphasize ideology. Lastly, creationists attack all science and history: evolution is just the most prominent of their targets.

After a break for the replenishment of glasses, the Q&A session followed. I was lucky enough to get the first question, and asked about how the relationship between protostomes (most animals) and deuterostomes (chordates, echinoderms and a few other small phyla) fits into the picture PZ had given – specifically, in relation to the role of Hox genes. PZ explained that a protostome is in effect an upside-down deuterostome (or vice versa), having a ventral nerve cord and dorsal heart rather than the reverse.

The next question was from a creationist – apparently, if not the only one present, one of very few. He attempted a classic “Gish gallop”, asking a string of questions without giving any opportunity for response, but it was actually more of a “Gish gabble”: he spoke so fast and so incoherently that I for one could not make out much of what he was trying to say (to be fair, something he certainly was not attempting, it can’t be easy to conduct a Gish gallop when you know both speaker and audience hold you in contempt). The general line was that of the 10 questions referred to above. PZ responded by asking him if he was not ashamed of himself (but of course creationists are without shame when lying for Jesus/YHWH/Allah/Sun Myung Moon), then requested that he ask a single question. This, I think (he was still gabbling), came down to the misconception underlying the 10 questions, and a claim that changes in the early development of the embryo would always be fatal. When PZ dismissed this nonsense he had the impertinence to say his question was not being answered.

The third questioner (not apparently a creationist) asked whether the Hox genes couldn’t have been produced by “the designer”. PZ agreed that there was no way to rule out a designer acting to mimic natural processes, but absolutely no reason to believe this was so. The pirate later got a laugh by asking about the evidence for unintelligent design (which, I think we must admit, is quite strong :-p).

Remaining questions were mostly less closely linked to the talk. A number covered issues specific to the UK or Scotland (A.C. Grayling’s proposed private liberal arts college, how to combat attempts to smuggle ID into British classrooms and to restrict abortion in the UK, and whether PZ had yet encountered something called “Irn Bru” – which I believe is some kind of drain cleaner – PZ said he had tasted it, and would stick with the Glenlivet.) PZ saw no specific problem with Grayling’s college – an issue on which I, like most left-leaning Brits, would profoundly disagree. Another questioner asked whether creationists might over time be selected out, but PZ pointed out that they tend to have lots of kids, and in any case, creationism is not genetically heritable: we should in no way write of the children of creationists – although adults, as he said in answer to another question about the balance between convincing creationists and fence-sitters, may well be beyond help. The best way to combat creationism is to get involved in your local school, stick up trenchantly for good teaching, and campaign to fund all schools properly and equally – the US has a specific problem in that public schools* are funded through local taxation. A related question led him to cite favourably Dennett’s support for the teaching of comparative religion – which, as an audience member pointed out, is already done in Scotland (to a limited extent, I would add – my son’s schools have certainly favoured Christianity, although he enjoys his “RME” (religious and moral education), as a chance for the majority of atheists to argue with – and mock – the Christians and Muslims).

Another question brought an exciting reply: PZ’s book now is now undergoing revisions and has a planned publication date of May 2012! It’s focused on atheism and the absurdity of religion. It will be “like The God Delusion, but funny and aggressive!” (Go for it PZ, show that accommodationist milksop Dawkins how it’s done!) Yet another asked about the Plos One system of “Open Access” publishing, which PZ considers is essential. Most peer-reviewed papers published are crap – because of the pressure on academics to publish as many as possible: the “least publishable unit” (LPU) syndrome. Peer review remains essential, but everyone should be able to do post-publication review.

The final question returned to the topic of religious education, and gave PZ the opportunity to end on a key point: “Teach kids to think: that’s all we care about.”

Most people stuck around for further drinking and talking, and to all appearances, a good time was had by all. Shortly before I left for my hotel, the gabbling creobot, who turned out to be a biology undergraduate – an aspiring Jonathan Wells, perhaps – was brought over to argue with PZ, but almost immediately declared that he must leave as he had to catch a train. Who knows, it may even have been true!

*In the UK, bizarrely, the term “public schools” refers to the top tier private schools, the rich having captured them for their sons – they were originally intended for bright boys from relatively modest backgrounds – some centuries ago. The real public schools are called “state schools”.