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

(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?

(Christy Hemphill) #549

But this violates the concept of species, doesn’t it? How is there ever “the first” mating pair of a species? Species transition over time as a population. Any divisions are arbitrary divisions on a development continuum that does not have precise boundaries down to individuals. Now it looks like you are conflating Homo sapiens with human.

(Andrew M. Wolfe) #550

If there’s one thing I thought I’d learned in this conversation (the most recent part of it — yesterday and today), it was that you may be able to meaningfully say that there was a first “human” couple if you define human relationally or theologically, but you can’t say that there was a first “human” couple if you define human genetically (H. sapiens) or behaviorally (“behaviorally modern” humans).

If I’ve got this wrong, I hope Joshua will clarify.

Biological Definition of "Mankind"
(Jon) #551

I agree. This is the kind of parsing to which I referred in my previous post. One minute a term means X, the next minute it means Y, then still later it’s swapped out for Z. It feels horribly like a bait and switch is happening each time.

(Lynn Munter) #552

It is possible one could recognize a sharp species boundary at a point when the number of chromosomes changed, making interbreeding difficult although probably not impossible. That did happen once between the chimp split and us but I doubt it was at a human-defining moment we’d think much of. Other than that I couldn’t say.

(Christy Hemphill) #553

So the number of chromosomes changed in only two individuals? How is that possible? And they happened to find each other and mate?

(Lynn Munter) #554

It would change in one first (identical twins tangent … no, not going there) but then they’d have a kid? And either inbreeding, or the chromosome number isn’t as much of a fertility issue early on as it becomes later.

(Lynn Munter) #555

His clarification was about three words. What you appear to be going off of is your further clarification/restatement which he agreed to, which is fine for some purposes, but not for saying he should put a retraction in the next edition of his book.

(Jay Johnson) #556

I really wish you would stop saying “adams”. The Hebrew in Gen. 1:26 is adam, which is a collective noun meaning “mankind”. It is not a Hebrew plural, formed by adding -im, so what you’re doing is, in effect, talking about “mankinds” every time you say “adams”.

In any case, if you’re trying to define a theological category of “adams” in contrast to the biological category of “mankind,” I reject the distinction. We can have a theological definition of mankind and a biological definition of mankind, and they may be entirely different. But that is a far different thing than saying God created a “theological mankind” separately and at a later date than his creation of “biological mankind.”

All of humanity developed through one evolutionary process of creation. That is parsimony.

Biological Definition of "Mankind"
(T J Runyon) #557

I agree. Some of this word play is just becoming silly and I am quickly losing interest in this thread. I’m interested in if Homo sapiens, a species that is 350kya give or take ever dipped down to two. And the way I read Dennis’ book was that the view that we are the descendants of two individuals that were created de novo is false and this as certain as heliocentrism. I couldnt care less if Erectus dipped down to two. And as someone who dedicates much of his time to Erectus, the view that Adam couldve been Erectus just doesn’t match the data. I just want to know did our species ever dip down to two and is if even possible without that pair being descended from a larger pre Sapiens ancestral population?

(Dennis Venema) #558

Lynn has the correct sense of things. I too am not really interested in grammatical hair-splitting! Nor do I see a need to revise the book. “Descending from just two people” is talking about populations and genetics, not genealogy. Yes I was aware of the genealogy issue - that is why “only” is in there. In other places, I’m careful to say we don’t descend “uniquely” from just two people, etc.

(Dennis Venema) #559

Oh, and chromosome number change by fusion isn’t a speciation mechanism (in vertebrates, anyway). It happens in one individual, who then mates with others with the usual set. In the human lineage, this occurred before Neanderthals and Denisovans branch off.

48 --> 47 --> over time, more individuals with 47

47 mates with 47 —> some have 46

Over time, 48, 47 become less common, and our lineage fixes on 46.

(Lynn Munter) #560

Thanks for the clarification! Does it not cause fertility issues at all, or just not issues sufficient to prevent offspring?

(GJDS) #561

Perhaps we misunderstand each other - I read your statement to mean there should be two classifications of humanity (eg non-theological and theological). The subsequent comments show some type of biological change and this excites others into speculation regarding Adam and Eve.

I think I will leave this conversationit at this point.

(Christy Hemphill) #562

I don’t personally think that, but yes, that is how some people talk about it. There is the species Homo sapiens (biological human) and then people speculate that within the species (or an earlier one) there arose a group or a couple that were the first “theological humans;” the first to have a relationship with God, or moral accountability, or an eternal soul, or the image of God, or whatever it is that one uses to define “human” theologically.

(Dennis Venema) #563

The fertility issues are mild.

This sort of thing still happens - there’s an example of a man in China with 44 chromosomes - his parents both have 45, and the fused pair they have they inherited from a common ancestor.

(Andrew M. Wolfe) #564

For what it’s worth, I think that a number of folks here (or perhaps just @swamidass and I) don’t even necessarily feel this distinction is the best way forward for ourselves, but have been exploring it for the sake of those who cannot bear to accept evolution if it means jettisoning a singular historical Adam.

This sort of “saving the phenomena” approach seems to be tiring folks on this thread, though, and it’s not properly speaking the topic of the thread…