The "Unique" Ancestors of Everyone?

If by “unique” they mean “biologically unique”, then the 6-10 kya GAE model wouldn’t really count right? In GAE, A&E are (potentially) unique because of their theological status, not biological (as there are other universal ancestors living near their time, and the model doesn’t posit them to necessarily be biologically unique).

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If we have to start making extend qualifications of our sentences to make our point, it’s probably not the right language.

There are some ways to construe this can be correct. I think I laid out how that could be done, by adopting one particular set of definitions that is out of step with at least two other positions.

To be clear @dga471, that’s a side point, right? Maybe people disagree with me, but I can be clear my position and why.

I agree that I would revise the wording of the latest BL statement to make it clearer and make space for other models of A&E (such as the GAE) which have been shown to not be inconsistent with the science.

However, fixation on biological uniqueness (and other unstated assumptions as well such as "human = Homo sapiens) has been common in certain sectors of the debate, so I’m unsurprised that they word it that way. This is precisely what makes the GAE book important, because it questions these assumptions and reframes the debate. But it takes time for people to change.


They doesn’t mean it that way in this population genetics context. They do not mean biologically unique. There is general ridicule of the notion that the bottleneck couple would be biologically unique.

What the are claiming is that Adam and Eve are solely and uniquely the ancestors of all humans in all history. I know because I’ve asked that’s what they say. @glipsnort uses their language too, and I’m sure he’d agree.

The problem is the next logical leap.

They tacitly or explicitly claim that this definition of Adam and Eve entails a bottleneck of 4 alleles.

That’s just not true. It’s frank falsehood.

Point this out and there is complains about “word games” when the real issue is a false inference they are relying upon. There are now three prominent models that satisfy their definition of “solely and uniquely progenitors” (WLC, GAE, RTB) without entailing a 4 alleles bottleneck.

All these models rely on interbreeding between AEs lineage. When pressed, they will say that’s what they mean by solely and uniquely, as a way of excluding that possibility.

Okay, but that is not entailed by the definition of the term. They should just state clearly that they mean models of AE that do not include interbreeding. If that’s what they mean, that’s why they should say.

That’s solution, in fact, we’ve adopted. If a theological model tolerates interbreeding between AEs lineage and others, that mode does not entail a 4 allele bottleneck. If AE have normal biology, and their lineage did not interbreed with others, in a 4 allele bottleneck is entailed.

So why won’t BioLogos adopt the obvious solution? From what I can tell, and what’s been told to me, there are two primary reasons.

  1. They invested a lot of reputational capital into claims that this 4 alllele bottleneck is important to the conversation, and their preferred language bolsters that sense of importance.

  2. They take the evidential high ground against groups like RTB, claiming to have evidence against them.

  3. It’s obvious that the Genesis tradition does not demand AE’s lineage were pure, so using clearer language totally deflates their claims of demonstrating traditional understanding of Genesis false.

  4. they do not personally benefit from understanding the issue. It’s better to keep doing it and claim ignorance than to make space for people they disagree with.

In this sense, I’m talking on a the level of group reasoning. The fact that so many smart people are resolutely holding to this language demands some explanation. In individual cases, it might merely be innocent mimicry of people who probably should know better.

Ultimately, clinging to that language is just breeding a lot of unnecessary conflict and confusion. Though some scientists at BL know better, BL claims to have genetic evidence against RTB. The root problem is that the two groups are using terms in totally different ways.

In general, when making scientific claims we need to stop using theologically charged language in ambiguous ways. We need to stop loading up terms with hidden axulliary hypotheses. The scientific discourse needs to conducted with concrete words, that are not deeply contested, and not theologically charged. Otherwise we usually end up talking past one another, as is happening right now.

Yes, and I think that’s playing word games. If “solely and uniquely” mean anything, there can in fact be no interbreeding. GAE doesn’t fit “solely and uniquely”. The RTB model that I haven’t seen so far would seem to postulate an massively polymorphic germ line for Eve, and that gets more than 4 alleles without interbreeding while retaining “solely and uniquely”, but again interbreeding has nothing to do with it.

But it is!


That’s just cause you are using different criteria. There are criteria for which they are solely and uniquely ancestors of us all.

The whole point is that those term are ambiguous to a fault.

Even if we grant your definition this isn’t true. Their biology could have been different than us.

There isn’t at good reason not to bring the hidden assumptions to the surface.

That’s definitely “word games”, in which “solely” doesn’t mean “solely” and “uniquely” doesn’t mean “uniquely”. I can’t accept that, and the terms are not at all ambiguous unless you purposely strain to make them so.

How is that relevant to “solely and uniquely”?

The assumptions aren’t hidden; they’re entailed in the meanings of the words. The only hidden assumption is the idea that Adam and Eve were not supernaturally polymorphic, but that’s relevant only to a four-allele bottleneck, not to a two-person bottleneck.

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I think that’s exactly right. Indeed, if “solely” and “uniquely” do not mean, in this context, what they obviously appear to mean, then I don’t know that there are any words left to express what “solely” and “uniquely” ought to have meant.


The issue is that there are other contexts that are more Germaine to Adam and Eve. It is a big mistake to think that this particular and idiosyncratic genetic paradigm that emphasizes a 4 allele bottleneck is Germaine to theology. It is not.

I think Josh’s way of seeing it has a point. For example, if you want to be a member of the Monticello Association, you have to be a lineal descendant of Thomas and Martha Jefferson. Let’s call such people Monticellians. It is accurate to say that Thomas and Martha Jefferson are the sole Monticellian progenitors of all Monticellians. This is true even if some Monticellians may have other ancestors who are not Monticellian, because this simply means that Thomas and Martha Jefferson are the only couple who must be among your ancestors in order for you to be counted as a Monticellian.

Replace Monticellian with “humans according to theology” and we have a similar situation with Josh’s claim that the GAE model has A&E as the sole universal progenitors of [theological] humanity.


That’s exactly right.

We also see some examples of this use of the language in Scripture too.

First, I don’t think there’s anyone named Germaine in the story, so I think you may have this confused with the Jackson Five. On that, Joe and Katherine were the sole and unique parents of the Jackson Five, but when the Five started having children themselves, Joe and Katherine were not the sole and unique progenitors of those children, unless there was inbreeding. And while the family got up to many things, that probably wasn’t one of 'em.

Second, while the four-allele bottleneck may not be germane to YOUR theological views, it plainly is germane to the views of many, many people. And that being the case, referring to Adam and Eve as the “sole and unique” ancestors of humanity has an existing meaning and it isn’t one compatible with your views.

“Humans according to theology” isn’t a thing. And “humans according to a very particular thread of theology” may be a thing but it surely needs something much more clear than these kinds of terms of general reference to describe it. To the world, descent is something that happens when critters have offspring. And the human species has been doing that for a good long while. Referring to Adam and Eve as the sole and unique ancestors when that isn’t at all what you mean in the ordinary sense is confusing, at least, and just inaccurate, at worst.


Is that true? Not just a lineal descendant of Thomas? Was that a recent change to leave out all those black descendants, or was it always true?

Yes, but they aren’t the sole and unique ancestors of all Monticellans.


Ain’t nobody here talking about a 4 allele bottleneck. And A&E are not sole, unique ancestors of us all under GAE. They’re the sole, unique ancestors of that by which we are judged to be textual humans (by definition, which again seems to be a word game; that, however, is another controversy), but that doesn’t mean the same thing.


I don’t know much about that history. I’m just going off the Wikipedia article. There certainly does seem to be a controversy about whether the descendants of Thomas Jefferson with Sally Hemmings should be accepted as members or not.

Yes, the ancestors of Thomas and Martha Jefferson would also be ancestors of all Monticellians. So they’re not unique. But imagine if Thomas and Martha were created de novo, without ancestors. Then they would be the sole universal ancestors of their descendants, even if interbreeding with non-Monticellians occurred. That would be more similar to the GAE model (and could point to why some people might want to posit de novo creation).

Even in the hypothetical extreme case where Adam and Eve had only one son, Seth, who married a non-sibling, then his wife (and her ancestors) would also be the universal ancestors of all the descendants of A&E, except Seth himself. Thus A&E remain the sole universal ancestors of the set of humans consisting of their lineal descendants, which is composed of Seth + his lineal descendants.

In this example, who are the progenitors of the set of humans consisting of Jackson Five and their lineal descendants? Only Joe and Katherine (and their ancestors).

Furthermore (as with my treatment example of the Monticellians above), if Joe and Katherine were de novo created and without ancestors, then they would be the sole progenitors.

One of the main points argued in Josh’s book is that the “ordinary” sense of what “human species” means according to scientists and according to theologians may not be exactly the same, and we shouldn’t blindly assume they are the same.

Is it really though?

It isn’t to RTB and WLC, and even Catholics that affirm monogenesis.

Of course some people think it is (as did RTB and WLC), but soon found that it was a poor model of their position. So the root issue was a gap in scientific understanding. As soon as they understood what it was, they were clear it was not their view.

Not exactly. Rather, they are the only progenitors of ALL members of that set. They are not the sole progenitors of the set, because each member, beyond the Five, has other progenitors.

Sure. But there is no sense in which Adam and Eve, under this model, are the “sole and unique” progenitors of humans today, unless one uses those descriptors in a tortured fashion.

Now, theologians may have speculations to offer about what they consider “human,” and I am sure that those speculations have as much value as all of their other speculations. But as for the human “species,” I should think that that’s not a meaningful concept outside of biology, and I cannot imagine how anything in which theologians are expert can bear upon it.

Yes. Perhaps you have never had the misfortune of living in a place where that sort of rip-roaring faith is prevalent, but I have. They literally believe that there were no other humans (in any biological or theological sense, to be clear) around when the Lord of Boasts showed up, mixed up some dirt, and made Adam. The four-allele bottleneck is inherent in that model. And I dare say that the chaw-chomping, frothy enthusiasts of that stripe outnumber the adherents to GAE by some margin.


This is an argument about definitions. There is no central authority by which to adjudicate this.

The sooner we move to recognizing that other people use the same words differently the better. They have a right to do so. There is value in understanding precisely what they mean by their use of words. And there is value in developing shared vocabulary.

Shared vocabulary does not come from a central source authority. Rather it has to be negotiated.

What’s going on here is an unwillingness to negotiate on both sides, often for theological reasons, some which are legitimate. Some of which are not.

As scientists we should look for secular vocabulary that bypasses those theological agendas.


Yes. But if we define “all members of that set” = humans according to theology (minus Adam and Eve), then we can say that Adam and Eve are the sole progenitors of humanity.

There is such a sense, as has been argued above. Whether it’s “tortured” or not is subject to people’s personal credibility. The fact that Josh’s book has had a pretty positive reception among several professional theologians and biblical scholars that are involved in this debate gives support that it is not as implausible and tortured as you might think.

But precisely because human species is not a meaningful concept outside of biology, then it doesn’t make sense to interpret what theology has to say about humanity in terms of “human species as understood in biology”. So I don’t really see the disagreement here.