Adam, Eve and Population Genetics: A Reply to Dr. Richard Buggs (Part 1)


(GJDS) #529

So we are left with a question, which very simply may be phrased as, “Why do we seem to turn to science for answers that science cannot provide?”


(Peaceful Science) #530

The fundamental error here is summed up in an old joke scientists love to tell. Late at night, a police officer finds a drunk man crawling around on his hands and knees under a streetlight. The drunk man tells the officer he’s looking for his wallet. When the officer asks if he’s sure this is where he dropped the wallet, the man replies that he thinks he more likely dropped it across the street. Then why are you looking over here? the befuddled officer asks. Because the light’s better here, explains the drunk man.

http://discovermagazine.com/2010/jul-aug/29-why-scientific-studies-often-wrong-streetlight-effect


(Christy Hemphill) #531

I turned to science for the answer to the question, “Did humans emerge from a population that has not dipped down to two organisms within the last 300,000 years?” Science answered my question just fine.


(GJDS) #532

But surely @Christy this simplistic approach poses more questions than answers. As a scientific question, we need to know what are these humans within the model, when did they “emerge” (whatever that means), and why are we confined to an elaborate analysis of genetic diversity in examining these matters. We have abundant data from archeology, history and perhaps geo-chemistry to seek answers to scientific questions - questions on human history, and “emergence” of the human race can only be answered adequately with science, by providing a coherent approach that uses all available data.

It is worth noting that modelling that looks at genetic diversity over the past few thousand years can be shown to be consistent with population modelling of humanity based on available recorded data. I will indulge in speculation (since this seems the fashion) by posing a thought that a history spanning 10-30,000 years would be sufficient to answer our questions of ancestry and the theological/spiritual behaviour of true humans.

In any event, I remain unconvinced that any modelling of bottlenecks would have relevance to the matters pertaining to Adam and Eve as discussed within Christianity.


(Christy Hemphill) #533

Come again? The whole point of half these discussions is that “theological human” is a different construct than the “modern human” construct proposed by anthropology. We do not have “abundant data” to answer the question “when did humans emerge” in theological terms. We have Genesis and a bunch of creative speculation.

Oh, I totally agree with that.


(Peaceful Science) #534

Exactly. However…

Don’t forget your question. It still applies…

So @Christy is right…


(GJDS) #535

I cannot make sense of this comment - I am aware of details of tribes and civilisations that span thousands of years, which all show various cultures and spiritual outlooks. All of these, as far as I know, are considered modern humans. Adam and Eve are a specific couple that is part of the Jewish /Christian tradition.

My impression has been that BioLogos has sought to turn Adam and Eve as either into a myth, or as unscientific by showing that it cannot fit into the modelling of genetic diversity, as the latter would need to show a primordial “bottleneck” of a single couple in the model.

I have questioned the premise underpinning the modelling effort and am unconvinced the model has provided any worthwhile insights regarding Adam and Eve.


(GJDS) #536

I am questioning the distinction put by Christy - see my comment to her.


(George Brooks) #537

@Jay313

If we are going to entertain the idea of the creation of a special mating pair in the middle of another population, we might as well give them the maximum latitude for what the genetic diversity can be … locked up in the genes of the single mating pair. It’s a wild card I’m willing to let them play … but only once.

@DennisVenema, no doubt it rubs you the wrong way … because you are trained not to look at things as God enabled… but I don’t think it really changes things. Does it? If it does, now is the time to discuss it.


(Lynn Munter) #538

Hi, @Swamidass. I’m going to go over some of these details from your post bringing back the whole issue of the heliocentric claim, since (as I did before) I still think you’re being overly harsh on it.

Sorry, I think this statement (with Dr. Venema’s original correction) still stands, from everything I’ve seen. Your argument that

does not falsify it since your plural couples != “only two people.”

What happened here is that you restated the claim in a way that turned out to be false, and @DennisVenema incautiously agreed to it. But his original claim, with his minor clarification, is not false, yet you persist in calling your erroneous restatement his claim.

I think it doesn’t take much to realize he meant the subset of “our ancestors” which are reasonably considered “human” or “homo Sapiens.” When a word is clarified, it retains the original meaning but is limited in scope by the clarifying word. The context of his clarification was clearly that he did not mean the set of “our ancestors” stretching back to the other great apes.

But let’s return to his original wording. There are actually two separate claims here to which he did not feel tarnished by comparison to heliocentric certainty (the claim does not even state we are ‘as sure’ of them):

Now the later clarification that by “people” or “humans” he means “homo sapien,” not older human ancestors.

The first statement remains true. We do not descend from only two Homo sapiens. The suggestion of interbreeding cannot help you with this because if we descended from two Homo sapiens and some Neanderthals, that is not the same as descending from only two Homo sapiens.

Plus, it is not enough to demonstrate we cannot rule this option out: in order to falsify this claim, we must find actual positive evidence.

The second claim is what the actual humans=homo sapiens clarification applies to, and I think we can see that it works just fine with that substitution. “Homo sapiens evolved, and we evolved as a population.” Clearly this does not take out the ‘we’ meaning once ‘Homo sapiens’ is substituted in. Crossover events with closely related species is still “we evolved as a population.” If your only argument in refutation of this statement is that Homo sapiens could theoretically have had a population of only two at some point in time and we just wouldn’t be able to see it because of all the other non-Homo sapiens that subsequently exchanged genetic material with us, that is still “we evolved as a population.”

@DennisVenema may have gotten tired of defending this statement (or of grammatical hairsplitting), but as far as I can see nothing in this discussion has invalidated it.

It is unfortunate indeed that the conversation has gotten sidetracked by your (less well-worded) claim. If you wish to continue saying he should retract his agreement with it, you have a right to, certainly, as long as you stop conflating it with his.


(Christy Hemphill) #539

I don’t know how to clarify. How do you envision science coming up with anything useful pertaining to questions about eternal souls, the image of God, the Fall, evidence of God relating to humanity, or any of the other theological elements used to designate “theological human”. I can’t envision how science would shed any light on these questions.


(Lynn Munter) #540

I kept thinking about this after I posted because I wanted to be sure I was being fair. There is a grammatical ambiguity in this sentence, and it might be where a lot of this confusion has come from. It’s been long enough since my college linguistics classes that I’m not up to diagramming the sentence to show it, but I think it comes down to “(descend from only) (two people)” vs “(descend from) (only two people).” The difference is whether the statement allows for us to descend additionally from non-people.

Grammatical ambiguities like this are common in English (and, I imagine, other languages) and usually are resolved by looking at the context in which they were written. I think this ambiguity is entirely resolvable for two reasons. The first reason is that common sense tells us he is refuting the tradition of the sole progenitorship of Adam and Eve.

If we are still uncertain, however, we need only go to the end of the paragraph to see him restate the claim, we evolved as a population, this time making clear that it is the first sense (there were more than two) and not the second sense (there was a point when only two of our ancestors were human).

In case there is any doubt that what he is doing is restating the claim, we need only compare the first and second clauses, which are restated in order (parentheses mine):

1a: we were created independently of other animals
1b: we did not descend from only two people
2a: humans evolved (from other animals)
2b: we evolved as a population (more than two individuals)

P.S. I have now officially given up any hope I ever had of not being too nitpicky about this, but at the very least I seem to be in good company for it so I hope you will all forgive me!


(Peaceful Science) #541

I totally agree with you here.

Post Hoc Defense

@Lynn_Munter I’m not sure what your goals are here.

@DennisVenema is part of this conversation too, and he can certainly clarify his points and explain himself. He does not need a lawyerly defense from other people. In fact, it appears he has already retracted (in his way) the points you are defending. If I am wrong, he can explain himself. The fact that he is not should tell us something.

Except its not correct.

There is no model in which we do not all descend from multiple couples. Even in Ken Ham’s young earth creationist model, we all descend from many couples. This is scientifically a mistaken and incoherent defense. If you are take this definition, there is not a single model proposed that fits this criteria, not even the most YEC of YEC models.

Exactly. And there is ZERO evidence that they do not begin as a single couple. Zero evidence. So how do we come to heliocentric certainty about a claim substantiated by zero evidence?

Except the statement is false. We do descend from only two Homo sapiens.

Except there is no confusion; at least Dennis and I do not appear confused. As written, the statement that “We do not descend from only two Homo sapiens” is just false. There is more than one way to take it, and one way is not contradicted by the evidence. This is not nearly as ambiguous as you are making it. Unqualified, it’s just a false statement.

Of course, in context, it is possible other things were meant. However, clear explanations would have broken it down showing, (1) if you mean in this way, the answer is ‘no’, but (2) if you mean it this way, the answer is ‘yes’. Given that we are talking about a book designed to elucidate the key issues to the public this is a major error. It’s most clearly consequential in that McKnight concludes that a genealogical Adam is not consistent with science. Dennis’ own co-author is so confused by the this error he misunderstands a central fact about the science. That is Dennis’s co author, by the way, making his most controversial theological point based on a misunderstanding of the science.

It is rare to see a consequential error of this magnitude. It’s better to retract errors like this than give lawyerly defenses.

Now, once again, I think this was an unintentional error. Everyone has been making this error. It is, nonetheless, and unambiguous error that misrepresents what we know about the science. Going forward, no one has an excuse about this any more. These post hoc, word parsing only erode trust. The people that will be trust are the ones that fix this scientific error in their future work. Those that are trusted will own up to the oversight.


@Lynn_Munter you are welcome to disagree with me, but I’m 100% sure that @DennisVenema does not need your defense. I’ve been inviting him to correct it for over a month now, and he has demurred. Wisely, because I am not misrepresenting him.

Of course, a clearer retraction from him would serve you. However, that does not appear to be his style. This is how @DennisVenema makes retractions.


(Christy Hemphill) #542

What?

How is the statement “we descend from a population that did not dip below 10,000” true and yet “we do not descend from (a population of) only two” false?


(Jon) #543

He’s probably speaking of genealogical Adam.


(Peaceful Science) #544

We’ve gone over this several times. There is ambiguity in the grammar there. More precisely, we do all descend individually from two specific Homo sapiens. These two specific Homo sapiens are not unique, in that large number of others could be substituted in the place (from a scientific point of view). This is true of all models, including Ken Ham’s model.

Yup.


(Jon) #545

This is ironic since it’s your word parsing that has eroded my trust.


(Christy Hemphill) #546

Which is not the topic of conversation. The topic of conversation is population genetics. We all should not be expected to constantly mentally refer to genealogical Adam when making fairly straightforward statements about other topics.


(Peaceful Science) #547

Genealogical science is part of population genetics. Clarity in language is important, or a lot confusion persists. It’s not my intention to keep going there, but we can’t use language in a way that ignores that finding of population genetics.

However, you do have a point…

In this case, I am not making reference to genealogical science. This is just correcting the ecological fallacy.

There is strong evidence that our ancestors do not dip to a single couple in the last 500 kya, but that does not mean Homo sapiens specifically do not go to zero, or even a single couple at their origin.

Its not word parsing to clarify what people mean by statements, and then see if the evidence holds to it. It is not word parsing to seek clear language that does not miscommunicate the details of the science. Much of this would not matter if the science was clearly understood by everyone. However, that is not the case. Most people are missing key things. Until that is resolved, its going to require reworking our language.

In the conversation with Dennis, we are working off his clarification of what he original wrote. Not the precise language he originally wrote. Still, we can’t move the goal posts after those clarifications are made.


(Lynn Munter) #548

If that statement appeared out of nowhere, there would indeed be ambiguity and two ways to take it. However, it did not, and within its original context, it is very clear which way it was meant and it is not false at all.

I will give you that substituting in ‘Homo sapiens’ lends emphasis to your alternative meaning, because another way to tell how to parse a sentence is to look for the most specific words (‘two’ is more specific than ‘people,’ but ‘Homo sapiens’ is more specific than either) but that is no reason to change our established understanding of the sentence: We do not descend from only two people. (We evolved as a population.) I’m sorry but it’s more than adequately clear.

We don’t care at all how some arbitrarily defined population of Homo sapiens begins; we care if we are descended from a single couple and only a single couple. That is the topic of discussion. Is there or is there not a single couple from whom alone we all descend?

I am not qualified to converse at as high a scientific level as Dennis Venema and Richard Buggs. It’s great that you are qualified, and have provided a lot of very valuable contributions to the discussion. But if you’re going to pursue this issue of grammar as you have been doing, I do consider myself qualified to disagree with your conclusions as I have been doing.

I have not seen anyone else take the meaning from the statement that you do. If McKnight did and disagrees with your genealogical Adam on the grounds of it, I will be extremely surprised: I think it more likely that there is some other miscommunication happening there. I don’t know if you’re referring to a public conversation or a private one?