The proteus of evolutionary consensus

Larry Moran is a prolific blogger on evolution, and is respected enough to have big scientific names commenting in his threads. He’s also militantly anti-creationist and anti-ID, though he’s gained some respect from the latter group for being willing to engage in discussion with them, despite persisting in contemptuously labelling them “ID-creationists”.

Not only that, but he’s been eager to pounce on any weakening of orthodoxy within evolutionary theory. Back in 2012 he even wrote a piece accusing James Shapiro, the organiser of Third Way of Evolution and originator of “natural genetic engineering” theory, of closet creationism for admitting teleology within evolution, on which I commented (caustically) here.

Incidentally part of his case in that piece was to ask, “Do you know any respectable evolution supporter who would post on a creationist blog?” The answer to that is “Yes”, in that Moran himself has had quite a lot of activity on Uncommon Descent over the last few months, but hey, consistency is an overrated virtue, yes?

Now, Moran has recently posted a piece called “Why are most biologists adaptationists?” , in which he restates the claim that his own strongly neutralist position on evolution is now the current orthodoxy, but that regrettably he finds a majority of biologists and “even evolutionary biologists” haven’t caught up, and cling to adaptationist positions that are no longer tenable.

This stance of his is not new, and Moran argues it extremely well, as I tried to show in a piece of my own a couple of years ago. But in fact his direct source for the new piece is Prof Michael Lynch, whose impressive CV states that he is not only Distinguished Professor of Biology at Indiana University, but served as President of both the Society for the Study of Evolution and the American Genetic Association, and is a past council member of the Society for Molecular Biology and Evolution, and a fellow of the American Academy of Arts and Sciences.

So Moran is right to say that it lends some weight to his own position that Lynch recently told him that most biologists, and even most evolutionary biologists, don’t have a firm grasp of population genetics and the importance of random genetic drift.

Now, in the combox Moran was immediately challenged on his conclusions about the science itself by as august an adaptationist as Joe Felsenstein (though to me Felsenstein’s arguments seem as much to be handwaving as they did to Moran). But without pursuing that, I want to comment on the opinion of both Moran and Lynch that “most” biologists are behind the curve of progress, because it raises deep issues about scientific consensus.

I think Moran’s general position on the science would go down OK at BioLogos, where most of the professional biologists, like Dennis Venema, “Benjamin Kirk” and Joshua Swamidass do seem to have a good grasp of population genetics, and appear very on-board with the neutralist stance. The same is less true of many BioLogos commenters, whose remarks make it clear that natural selection is still assumed as the creative mechanism of evolution.

But in discussions some months ago, Joshua Swamidass seemed to be quite close to endorsing Moran’s position, first in distinguishing Neutral theory quite clearly Neo-darwinian theory, and then in suggesting that the former is now the theory of evolution. Consequently IDists and others who critique random mutation and natural selection are, in effect, flogging a horse that’s been dead for decades within the scientific community.

Joshua further (in other contexts) has excluded Intelligent Design science from the scientific playing-field on the grounds that it is rejected by the majority of biologists, who as the “owners” of the discipline have the right to decide what does, and what does not, count as true science. He uses the same argument more generally to say that methodological naturalism must be a condition of science because the majority of scientists say so and have the right to decide on the content of their own discipline, whether or not philosophers of science or any other outsiders challenge its validity. These are all arguments from consensus.

But do you see the problem I see in all this? If Larry Moran and Michael Lynch are right, then outside the field of population genetics itself, the majority of biologists believe that Neodarwinian adaptationism is, after all, still “the” theory of evolution. The consensus at the recent Royal Society Meeting in London seemed to be saying just that, if rather inconclusively: that the Modern Synthesis does not need to be extended, but can happily accommodate all the new science under the old umbrella of “random mutation and natural selection”. Neutral theory is not, after all, the new dominant theory, but a new epicycle within the old.

If such a view is, in fact, that of the majority of biologists with a stake in evolutionary theory, then rightly or wrongly surely they have as much right to say that Neodarwinism is the current theory of evolution as they do to say that methodological naturalism is indispensible or that Intelligent Design is inadmissable? Apart from meaning that the Creationists were tilting at real knights after all, not windmills, in attacking Neodarwinism this also entails that neutral theory (as a main theory) is is not the consensus view after all, and that Moran and so on are out of step with “the current state of science” – either that or some other means than consensus must define the mainstream..

Of course, neutralists like Lynch and Moran may be wrong about what the majority of their colleagues think, having not (one supposes) actually done formal research on it. In that case their neutral theory has won and it’s the adaptationists who are really the minority, but presumably a vocal one if they manage to sound like a majority. Moran’s being right about the science may indeed not guarantee he is right about the sociology of science – but how would we know where the consensus actually lies without enlisting the sociologists as the final authority on what current science is, leaving the population geneticists to do their genetic modelling rather than conjuring opinion polls? But are biologists going to submit their judgement on what the consensus position is to mere sociologists? They won’t even let philosophers of science criticise their methodological naturalism.

Perhaps a more productive way forward would be to stop pretending that a settled theory of evolution is currently actually even possible, and that there are in fact a number of approaches that are, in some cases, mutually incompatible, just as was the case before the Neodarwinian synthesis tidied things up. What is touted by population geneticists or others as “ignorance of evolutionary theory” may actually be “holding a different evolutionary theory altogether”.

Unfortunately that doesn’t suit the meta-narrative of science as an authoritative and growing body of Truth, but it is what some of us have been seeing for a long time. It’s not new, either – as the geologist and theologian G F Wright, one of the earliest theistic Darwinians observed in his later more skeptical period over a century ago:

[Darwinism’s] votaries are split up into as many warring sects as are the theologians. New schools of evolutionists arise as rapidly as, do, new schools of Biblical critics.


My own impressions are probably as unreliable as Moran’s, but I sense that it is the population geneticists, more than those in any other field, who insist that they, and only they, really understand what evolution is about. This seems strange to me, since population genetics is an example of a theory held not because it is true, but because it sufficiently closely “saves the appearances” to make predictions that appear to work. Though as Samir Okasha points out in the Stanford Encyclopedia of Philosophy (all further citations from there unless otherwise stated):

… even its effectiveness in that respect has been challenged:
Some argue that population geneticists have devoted too much energy to developing theoretical models, often with great mathematical ingenuity, and too little to actually testing the models against empirical data (Wade 2005) [Okasha, Samir, “Population Genetics”, The Stanford Encyclopedia of Philosophy (Winter 2016 Edition), Edward N. Zalta (ed.), forthcoming URL = <https://plato.stanford.edu/archives/win2016/entries/population-genetics/>.]

For population genetics is based on deliberately and drastically simplified modelling of the world, as Okasha discusses:

This leads us to another facet of population genetics that has attracted philosophers’ attention: the way in which abstract models, that involve simplifying assumptions known to be false, can illuminate actual empirical phenomena… In particular, there is often a trade-off between realism and tractability; the more realistic a model the more complicated it becomes, which typically limits its usefulness and its range of applicability. This general problem and others like it have been extensively discussed in the philosophical literature on modelling (e.g. Godfrey-Smith 2006, Weisberg 2006, Frigg and Hartmann 2006), and are related to population genetics by Plutynski (2006)…

…The simplest population-genetic models assume random mating, non-overlapping generations, infinite population size, perfect Mendelian segregation, frequency-independent genotype fitnesses, and the absence of stochastic effects; it is very unlikely (and in the case of the infinite population assumption, impossible) that any of these assumptions hold true of any actual biological population. More realistic models, that relax one of more of the above assumptions, have been constructed, but they are invariably much harder to analyze. It is an interesting historical question whether these ‘standard’ population-genetic assumptions were originally made because they simplified the mathematics, or because they were believed to be a reasonable approximation to reality, or both. This question is taken up by Morrison (2004) in relation to Fisher’s early population-genetic work.

So, as the great John von Neumann said:

“With four parameters I can fit an elephant, and with five I can make him wiggle his trunk.”

Now these problems have not been ignored in the internecine debates, as Okasha goes on:

In a recent book, Sean Carroll, a leading evo-devo researcher, argues that population genetics no longer deserves pride-of-place on the evolutionary biology curriculum. He writes: “millions of biology students have been taught the view (from population genetics) that ‘evolution is change in gene frequencies’ … This view forces the explanation toward mathematics and abstract descriptions of genes, and away from butterflies and zebras, or Australopithecines and Neanderthals” (2005 p. 294). A similar argument has been made by Massimo Pigliucci (2008).

I’m amused (in passing) how Carroll uses “change in gene frequencies” – a phrase which I was accused of willful ignorance for using by Benjamin Kirk, one of the biologists posting regularly at BioLogos. But on the substance of the matter, other research approaches than Evo-devo imply the same separation of population genetics from down-and-dirty facts. For example, if James Shapiro’s view that the genome is a read-write database were even partly correct, how genes are inherited would turn out to be as peripheral a subject as would studying the libraries, rather than the lives, of great men. And if epigenetics breaks the previously assumed direct link between genotype and phenotype, evolution is once more a black box.

Another criticism of the population genetics definition of evolution as “change of gene allele frequency” was made recently by an ID defender on BioLogos – and dismissed as anti-scientific by Dennis Venema. This was that it is unreasonable to extrapolate the “random” [sic] changes in the hypermutation of immune cells to the mechanisms involved in innovation and speciation. This is the old story of “microevolution” v “macroevolution”, which is sometimes claimed (usually by population geneticists!) to be a Creationist distinction, but which in fact marks the boundary between population genetics and other biological approaches like palaeontology:

Implicit in this definition [change in gene frequencies] is the idea that evolutionary phenomena such as speciation, adaptive radiation, diversification, as well as phenotypic evolution, can ultimately be reduced to gene frequency change. But do we really know this to be true? Many biologists, particularly ‘whole organism’ biologists, are not convinced, and thus reject both the population-genetic definition of evolution and the primacy traditionally accorded to population genetics within evolutionary biology (Pigliucci 2008)…

…Authors such as Gould (2002) and Eldredge (1989), for example, have argued persuasively that macro-evolutionary phenomena are governed by autonomous dynamics, irreducible to a microevolutionary basis. Philosophical discussions of this issue include Sterelny (1996), Grantham (1995) and Okasha (2006).

Another Stanford article quotes the founder of neutral theory, Kimura, obviously trying to open up the minds of opponents to his new theory:

As Kimura noted (1983, p. 22), “…if a certain doctrine is constantly being spoken of favorably by the majority, endorsed by top authorities in their books and taught in classes, then a belief is gradually built up in one’s mind, eventually becoming the guiding principle and the basis of value judgment. At any rate, this was the time when the panselectionist or ‘neo-Darwinian’ position was most secure in the history of biology: the heyday of the traditional ‘synthetic theory’ of evolution.” https://plato.stanford.edu/archives/spr2005/entries/evolutionary-genetics/#

That seems a principle applying to any consensus, including the new one on neutralism that Moran appears both to deny and embrace at the same time, rather than a one-off observation. Maybe one needs, then, to take what is constantly spoken of favourably by the majority with a pinch of salt, on principle.

Which particular theoretical basket should be used for the eggs of those trying to promote “Mainstream Evolutionary Creation” is another, more complex, matter altogether. Perhaps the wisest answer – following the footsteps of Augustine, Aquinas or Calvin – would be “none”.

Jon Garvey

About Jon Garvey

Training in medicine (which was my career), social psychology and theology. Interests in most things, but especially the science-faith interface. The rest of my time, though, is spent writing, playing and recording music.
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4 Responses to The proteus of evolutionary consensus

  1. Robert Byers says:

    A lot said but i pick up on the point that since these things are about past and gone events and processes then, on a curve, they are easily open to error and correction.
    After saying also everything is. Humans(tailless primates for some) have no claim to having figured out complicated things unless proven right well.
    So its not the ‘scientists’ who have a monopoly over their “own’ science. its humans who do and who have a monopoly over error also. Scientists are just other people who do it too. The claim of superiority must be proven.
    Anyways there is a original witness called the bible, written by God, and dismissing this is a first act.
    It is firing on fort sumter. figuring out natures story without the bible is not neutrality.

    • Jon Garvey Jon Garvey says:

      Robert

      I pick up on this of yours: “So its not the ‘scientists’ who have a monopoly over their “own’ science. its humans who do and who have a monopoly over error also.”

      For any academic discipline (or any other group of human actors) to insist on defining its own parameters is fine, but in the process it inevitably cuts itself off from relevance to universal human experience.

      A clear example is academic biblical theology – if it refuses to hold itself accountable to the Church, and instead insists on its own autonomy, then it actually undermines any authority it may have other than as a private club. You can end up as a leading New Testament Scholar in “the Guild” and yet know nothing that matters about the New Testament.

      So if, say, population genetics were the only biological disicipline that got evolution right, unless and until they can persuade both the other biologists AND the society they serve of that fact, they may as well be dead wrong anyway. Nobody else will either understand or care.

      The fact that non-specialists are prone to error ironically doesn’t actually help the people “in the know” to separate themselves off as the exception, because specialists are prone to all the many errors others have, without the correctives that others may offer.

      That’s put rather unclearly, but examples would include the way many scientists, by ignoring philosophy, fall into elementary errors about knowledge itself; the way that supposedly “pure” small Christian sects make the mistakes that others could have warned them about if they’d not shut their doors; or the way that governments that cut themself off from the consent of the people always end up in disaster.

  2. Sy Garte Sy Garte says:

    Jon

    Sorry to be so late to comment. Congrats on a great summary article. From my own perspective, the sense of confusion you relate concerning neutral theory, pop genetics, neo Darwinism etc, is absolutely correct. Of course neutral theory is derived from pop genetics, Kimura simply added some new ideas to what had been a very limited theory. The great attraction of pop genetics to “explain” evolution was its mathematical structure. “Yay” said the biologists, “Now we can use math, so we are just like ‘real’ scientists” While change in allele frequencies in a population over time” sounds great as a mathematically demonstrable definition of evolution, it doesnt really say anything. The problem of course, is what drives delta p is the change in fitness, (usually called w) and fitness, while it can be given a number (as our friends at Biologos have often said) is beyond any kind of definition. And of neutral changes can prevail when populations are small enough, than w becomes irrelevant.

    So which of these are right? The answer is clear, none of the above. The Okashi quote talking about the problems with models is key. Mathematical models of evolution have all failed at some point, or they have succeeded very well for some fraction of the biological world, and failed miserably with the rest. So, yes, what we need is a unified grand theory of evolution. I believe we are very far from that goal.

    • Jon Garvey Jon Garvey says:

      Pah! You clearly don’t understand the theory of evolution…

      Sy, did you come across Will Provine’s last book, reviewed here: http://www.christopherxjjensen.com/2015/11/05/review-of-william-b-provines-the-random-genetic-drift-fallacy/ ? (Why has the latest WordPress version lost those useful reminders of coding for links etc?). He argues that mathematical problems with Fisher’s original formulation have been carried over into Kimura’s theory, undermining the validity of both.

      The response generally from population geneticists has been to say he doesn’t understand evolution, that it’s the ramblings of a dying man with a brain tumour (reminiscent of the response to Anthony Flew’s There Is a God) and so on. But there are few people who have had a greater role in documenting the development of the Modern Synthesis, so I guess one must ask those who understand the maths but aren’t committed pop. geneticists, and make ones own judgement.

      The bottom line for Christians, as our friend GD was trying unsuccessfully to point out at BioLogos a week or two ago, is that to nail ones colours to one particular theoretical mast regarding evolution is foolish, especially when one lets that theory determine ones theology.

      That is, of course, unless one happens to be a biologist, in which case it’s your job to nail your colours to a theory, at least provisionally. But surely that shouldn’t mean cajoling your non-professional brethren that your game is the only one left in town.

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