Once more I’ve posted a few comments on BioLogos and got into trouble. Well, that’s been the pattern since 2011, so it’s no surprise. The thread was the old and currently 827-comment-long Buggs/Venema/Swamidass conversation on the population genetics of human origins, a lull in which made me think it was timely to add the kind of cautionary note on the validation of models I’ve sounded here and here.
It was a simple observation, that however consistent a scientific model, established on present populations, is with other models, and however many error bars one calculates, applying it to the distant past adds a further layer of uncertainty. That is because one cannot, in the very nature of things, test the “unknown unknowns” that might apply in that distant situation.
That is why history is always a provisional discipline, the past being interpreted through what are always under-determined data, and subject to reinterpretation even without the discovery of new data. The same is also true of the historical sciences, again in the nature of things. Problems arise when “Science” is given a capital “S” and treated as an ultimate source of knowledge, without due regard being given to its inherent uncertainties, including the human origin of all theories.
A relevant case in point: population genetic phylogenies not infrequently disagree with morphological phylogenies from fossils, as is well-known. One can, and people frequently do, argue for one methodology being correct (and surprisingly, genetics seems to win amongst lay people now, I suspect because it is more technical, whereas morphology appears to be more like artistic connoisseurship even when applied to cladistics). In both cases, though, assuming the data is OK, the problem may lie with with theoretical error – or incomplete information about contingencies.
But both being historical sciences, one can’t go back to check the truth, but only try to refine the models until they agree better. And even if they do finally agree, the evidence of the past is still under-determined. So one ought to retain a very strong sense of “our best provisional estimate”, rather than “the assured results of science.” This is not science-denial, but epistemological caution.
However, the responses to my drawing attention to this were clearly disgruntled, though I did get a “heart” from one moderator. It seemed that for me to suggest that the substantial agreement that had been reached by the population geneticists on the thread is nevertheless open to provisos, from outside the terms of the discussion, was taken to be an assault on the truth of population genetics theory.
Now it wasn’t such a denial at all, though it was a suggestion, on purely logical grounds, that applying population genetics to such a historical situation as human origins might involve unforeseen – and undetectable – errors. This applies to all such models, and the take-home message is simply to observe a bit of humility about the certainty involved in the conclusions. Incidentally, such a need for epistemological humility is equally true of rival interpretations of Genesis – since one cannot visit the past to check, one needs to accept some degree of provisionality in ones understanding, and that undermines neither Scriptural truth nor the value and necessity of drawing and defending conclusions about it.
However, most of the potential errors I had in mind were simpler than this: errors in the assumptions made about past conditions, simplifications thought to be unimportant actually being significant, and so on. That was my point – any historical science ought to recognise that no statistical tools can give one a perfect and objective window into the past.
But as a matter of record, there are – and have been for over a century – doubts amongst evolutionary biologists as to whether speciation arises merely from population genetics continuing over time, or some other factors not yet known. In the case of man, not only do we know of some complex hybridisation events between at least three subspecies or species of Homo, but there is currently, according to a number of palaeoarchaeologists, an entirely unexplained “saltational” gap between that genus and its nearest relatives in the fossils. Something interesting, beyond the pop. gen. model, may well be happening in the exact population under discussion. Caution is advised…
If to mention these elements in the literature (which weren’t, in fact, at the forefront of my mind) “casts doubt on the theory” and is therefore reprehensible, what happened to the principle of seeking to question all ones assumptions? It would appear that instead there’s some kind of psychological need for certainty going on, rather than either a desire simply for the most useful results, or (which should be greater in Evolutionary Creation discourse) the quest for God’s truth. Science is being defended (in a bristly way) as some kind of Absolute, and, rather amusingly, is being “reified” in the particular discipline of population genetics, so that to point out degrees of uncertainty in pop. gen. predictions is tantamount to attacking Truth.
If one can’t see a problem with that, then one has a very different perception of the world from me. If one can’t see a bigger problem with that in the context of a Christian conversation, then it’s even more the case (and I note that nobody, even my “hearted” moderator, was willing to counter my detractors at BioLogos).
For remember, the original question at issue was the existence of Adam and Eve, albeit it in a timeframe I, personally, regard as implausible. These two are first introduced in the book which BioLogos, as well as the “historical Adamists”, acknowledge to be the word of God. As BioLogos states:
We believe the Bible is the inspired and authoritative word of God. By the Holy Spirit it is the “living and active” means through which God speaks to the church today, bearing witness to God’s Son, Jesus, as the divine Logos, or Word of God.
This inspiring God was, it must be agreed on all sides, actually there in the past to witness the population of mankind in all its detail, at every stage. And not only is his Bible authoritative, the statement of faith says, but is acknowledged to speak to the Church, through the Spirit. It is not only data, but a living and active witness to the truth. The disagreement, then, ought to be finally between the fallible human interpretations of this “authoritative word,” some saying it is describing man’s origin simply historically, and others something else. Ultimately, it would appear to be the work of the Holy Spirit to settle the difference, being best placed to do so, through the Scripture itself.
That being so, to use the analogy, as one commenter did, that one would not allow a theologian to contradict a scientist on the position of a comet in the distant past, is saying far more than that science and theology have their own proper spheres – it is to say that the verbal witness of God (even with the best understanding its theological interpreters under the Spirit) must give way to the certainty of science – and not even science, but the particular application of one discipline, population genetics, which (as I have laboured to point out) carries entirely inevitable uncertainties in its application to the question of an original pair.
Now don’t get me wrong – I’m not denying the value of science, and I’m certainly not endorsing a literalist understanding of Genesis. There is epistemological uncertainty in interpreting Scripture, even accounting for the role of the Spirit. But there is nevertheless a clear mismatch between claiming that the Bible is the living and authoritative word of God to the Church, and then in practice taking one branch of historical science as the only certain arbiter on what the Bible actually means.
If it walks like scientism, and quacks like scientism…
Theology quit being a science and became a dogma centuries ago, and the natural sciences raced ahead in understanding and describing the universe, and now they too are succumbing to a temptation to become more dogma than science. If theology returns to more of a science it will certainly catch, and possibly once again surpass, natural science in some areas. …
https://earlygenesistherevealedcosmology.blogspot.com/2018/03/a-call-for-return-to-theology-as-science.html
Jon,
Modelling in the sciences is a sub-set of a particular branch or discipline. Thus genetics gives rise to their models (chemical kinetics to particular models, studies of molecules to molecular modelling, and so on). Each of these branches generate their data and use this to verify (or otherwise) their modelling, and each model has a specific purpose which is of interest to the particular branch.
I note that from the few papers I have read, population modelling based on genetic diversity seems to me to be a sophisticated type of data fitting, and I can see where you are coming from re medical models. By this I mean there is a data base that is generate in real time (now) and the model seeks a “best fit” base on a number of unverifiable factors thought to be relevant over huge spans of time.
I would not be overly concerned with this approach is these people confined it to their speculation – models are meant to be tools to further particular studies. I do object, however to the ridiculous extension into questions such as Adam and Eve, what we regard as true humans, and all sorts of other silly thoughts that some indulge in. I mean this to apply to both sides of the argument – I cannot see why modelling with a bottleneck of two, or two thousand, or two hundred thousand would be relevant to Genesis. So I have concluded this is an exercise in futility, even if I sympathise with Joshua regarding ceasing the “culture war”.
This modelling is a misuse of such exercises; I entered the debate in good faith, but I eventually became convinced that many people at BioLogos are there to put forward ideologies, and I cannot fathoms what else. It has diminished the site, in my view.
GD
I would not be overly concerned with this approach is these people confined it to their speculation – models are meant to be tools to further particular studies.
My point entirely. To ask the question “Does our model really exclude a small bottleneck” might be legitimately prompted by questioning the illegitimate exclusion of a first couple, but to then start defending those results as “fact” (worse, as fact which it is impious to question), falls into the modern trap of mistaking models for data – which I saw in medicine, but which is by no means unique to it.
To me, the fact that this exercise shows that the genetics seems to allow a much wider range of early population levels than before, including very small bottlenecks, ought to prompt questions about the mechanisms of speciation generally, rather than being used to test the Bible: is the usual assumption that species must arise from relatively large populations actually warranted, or could a single reproductive event produce a significantly altered new species? Interesting, but only peripherally theological.
This modelling is a misuse of such exercises; I entered the debate in good faith, but I eventually became convinced that many people at BioLogos are there to put forward ideologies, and I cannot fathoms what else.
This was my conclusion early on: having found that there was nothing in the science of evolution and so on that need contradict orthodox theology (or that couldn’t plausibly be reconciled in due course), I found BioLogos in 2010 in the expectation that they would have taken such work further.
Pretty soon, I found that the predominant aim was, instead, to prioritise current science, together with much of its present naturalist metaphysics, over the whole range of Christian teaching from biblical reliability to Incarnation theology, whilst protesting Evangelical orthodoxy all the while.
Pretty soon, I found that the predominant aim was, instead, to prioritise current science, together with much of its present naturalist metaphysics, over the whole range of Christian teaching from biblical reliability to Incarnation theology, whilst protesting Evangelical orthodoxy all the while.
A disappointing cheap shot from you, Jon.
Hey Jon,
Been observing that thread, deciding if I would jump in.
I think the point that you are missing is the way how our reasoning is going, and how modeling fits into it. You are right that modeling cannot lead us to certainty, but neither can anything else.
The way I see the situation, is that there is data we have collected about human variation. There is, at this time, a wide range of models proposed to account for that data. However, there is not a single model proposed that can account for the data with a single couple origin less than 200 kya, without either (1) inferring ongoing miracles, (2) totally different biology for Adam and Eve (e.g. genetic mosaics), or (3) mutation rates an order of magnitude (or more) higher than we have ever observed in humans.
That is why, based on our current knowledge, we are calling this evidence against a recent bottleneck. Until a model with a shorter time frame is put forward and tested, this is what we think the data is showing us. For those that disagree, they are welcome to put forward a model of their own to test, but failing that there is not really much to dispute.
Generically calling the conclusions into question is not helpful. The best way to unseat the conclusions is to produce a model that accounts for the data in a shorter time span.
“…..there is not a single model proposed that can account for the data with a single couple origin less than 200 kya, ”
If I understand the debate, it is that a bottleneck is “proven”, whereas when I asked for physical evidence that any bottleneck has been discovered or observed in any time frame, I failed to get a response.
I am forced to infer that a bottleneck of some size is required by the model – thus an inference cannot be considered a proven or verified fact.
To continue – a faulted interpretation is given by YEC that requires a single couple to begin existing 6k years ago, and this faulty interpretation is countered by these models that are used to account for genetic diversity.
This strikes me as faulty reasoning.
Finally we have models that account for the population on the earth and the so called genealogical ancestry – and this model is consistent with genetic make up, since genes are inherited from parents (and it seems modelling of genetic diversity is consistent with genealogical modelling).
So where is the theological problem regarding Adam and Eve? My conclusion is that there is none, but there may be a desire to (1) go after YEC by claiming evolution disproves Adam and Eve, and/or (2) put forward a heretical view of genesis and theology that deals with the first Adam and the last Adam.
In my view models of genetic diversity seems a ploy for promoting (1) and (2) and not the claim that this will give us certainty about anything, least of all a new version of Genesis.
This is easy to respond to GD.
“If I understand the debate…”
It does not appear you do understand the debate.
Perhaps you would be kind enough to enlighten me Joshua.
No one, NO ONE, has claimed in that thread to produce evidence of a bottleneck. That is why no one has produced evidence of a bottleneck. No one has made a claim that requires producing that evidence.
Rather, Venema claimed that there was evidence against a bottleneck going back as far as 13 million years. When asked to produce evidence to support this claim, he could not.
Instead, I produced evidence that seemed to rule out bottlenecks after 500 kya (given all the caveats I’ve stated). Before that point in history, it might be possible that a bottleneck is undetectable. So we would not be able to say one way or another from the evidence.
So no one is saying evidence FOR a bottleneck has been produced. We are saying, rather, that the evidence AGAINST a bottleneck before 500 kya cannot be discerned, but after that point appears to be ruled out.
We are discussing the LIMITS of the scientific evidence here, not what it shows us.
Thanks for this response Joshua. As I stated, I have not queried or criticised the modelling you referred to, but made comments on how it has been applied to the matter of Adam and Eve – I have stated this so often that I become bored with the sheer repetition.
Perhaps I may summarise quickly – the subject is Adam and Eve and what genetic modelling is supposed to show us. The critical component that has provided so much comment is that of a bottleneck – the inference being that if the model shows a bottleneck of two, bingo we have Adam and Eve, and if not, goodbye Adam (and what else?).
The limits of the model(s) you discuss deal with the question of absolute certainty claimed by Dennis.
If the bottleneck idea is not supported by evidence, as you say, the entire thread seems to collapse.
If you think this summary is not sufficient then please show me where that is the case.
1. The purpose of the thread was never to find evidence for a bottleneck, but to question the evidence against it.
2. As to hinging theology of Adam on this discussion, I agree with you. It is very much a red herring for most people. A single couple bottleneck 1 mya is not necessarily Adam and Eve. And a recent single couple could be ancestors of us all. So its not clear how many people will find this developement helpful.
“I think the point that you are missing is the way how our reasoning is going, and how modeling fits into it. You are right that modeling cannot lead us to certainty, but neither can anything else.”
Hi Joshua
I don’t think I missed the point, but simply added to the thread the caveat that, indeed, nothing can give us certainty, though it can narrow the possibilities (or, in some ways, increase them, as you did by showing a greater range of possibilities than Dennis had allowed for).
Dennis was mistaken in his application of the existing models, as you and Richard showed. But there is still the fact that the models are all being used to make predictions which, in the end, rely on the models being correct rather than confirmation from the physical world of the past. That’s the nature of historical science, but it often seems to be forgotten in the flush of producing a result. We have demonstrated to the best of our ability, but cannot quantify our remaining uncertainty except by acknowledgeing the limitations of scientific certainty.
There are no models (I’m not talking about pop. gen. models, but any models) based on present-world data that would predict the resurrection of a man in 33AD, but the event itself, and that alone, falsifies the models. There is relevance to that if one is considering the creation ex nihilo of one’s “bottleneck”, but history is also full of surprising contingencies that aren’t supernatural. That was my sole point.
“The best way to unseat the conclusions is to produce a model that accounts for the data in a shorter time span.”
God created a “host” on the earth (Genesis 2:1) between 50K and 250K ago. They had some genetic diversity to begin with, but not so great as say humans and neanderthals. Between 6K and 14K ago, the LORD God formed Adam, whose line has been mingling with the rest of his race ever since.
PS- bonus hypothesis- much of what we think of as the “evolution of modern humans” is actually shedding genes from introgressions of near-humans way back in the day. That is, Europeans look less like Neanderthals than Cro-magnons not because we are evolving so much but because over time the percentage of Neanderthal genes is getting weeded out so that we start to look more like humans originally did.
That is a great model, but it does not account for the genetic sole-progenitorship of Adam, just the genealogical sole-progenitorship. I favor that model, but it does not deal with the key question of a single-couple bottleneck of our ancestors in the past.
As far as “dealing” with single-couple sole progenitorship, well it says that there is none. It deals with it that way. I consider that you have already excluded that in any reasonable time frame for humans, so I guess I am skipping ahead to what sort of models might explain the evidence well within the parameters of your research.
Of course, I do support that enthusiastically. The likely fact that a single couple bottleneck is not ruled out 500 kya, does not at all detract from a recent genealogical Adam scenario. That, it seems, has much more theological plausibility.
Amen to that, Joshua and Mark. But our theological model, though it accords with the science, is still, equally, a model subject to the same uncertainty I placed on the population genetics modelling.
So it behoves me to hold it tentatively, lest the invention of the time-machine enables someone to rubbish the model by producing a specially created progenitor requiring us to rewrite the science and our biblical interpretation.
My uncertainty is not because it’s theology, or science, but because it’s just a human model. “Assured results” are the bugbear I want to challenge.
The thread has thinned out.
I agree with this:
“As to bringing theology of Adam on this discussion, I agree with you. It is very much a red herring for most people. A single couple bottleneck 1 mya is not necessarily Adam and Eve. And a recent single couple could be ancestors of us all.”
I remind you that the discussion began (long ago) from a book published by BioLogos on the Genome and Adam – so theology is central to the overall discussion in BioLogos.
That book claimed that science had ruled out things that science had not ruled out. That is why we took the turn to look at the science.
The theology of that book was widely panned too. It is a non-sequitor from a science to go where they go.
The work Jon has been doing on a genealogical Adam, I feel, has much more value going forward.
Thank you, Joshua. Is it insignificant that BL has never asked me to write about it these 8 years?
It is significant. Just as it is significant that they have yet to publish anything (as far as I’ve seen) on a genealogical Adam in general. They have a certain pattern and set of priorities, that does not include us.
I’m not sure what is so surprising about this, and it might even increase our impact. While I’d love to be embraced by BioLogos, I’m perfectly happy to triangulate them.
In no-man’s-land in the culture wars!
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