Oliver Crisp: Genetic Ghosts and Ancient Adam Models

I want to clarify an issue that may have a very quick answer (or previously answered).

First, I understand that if A&E lived recently, then they are likely to be genetic ghosts - i.e. the majority of people living today do not have genetic material which was initially uniquely possessed by them.

However, how does this transfer over to more ancient Adam models that incorporate interbreeding, such as the RTB model? Let’s assume that A&E had some unique pieces of genetic material G_{AE} that were divinely created and implanted in their genomes somehow. There seem to be three variables in play here:

1. How long ago A&E existed - call this t_{AE}.
2. How many humans existed at the time of A&E’s creation. (i.e. were they a two-person bottleneck or not) - call this N_{AE}.
3. How much interbreeding occurred between A&E’s descendants and people outside the Garden (including Neanderthals and other hominids) - call this the interbreeding rate R_{inter}.

Am I correct to say that some (or all) of the three variables above would affect the likelihood L that A&E are genetic ghosts for a random person living today? (In other words, the likelihood if you pick someone at random and examine their genome, you would not find G_{AE}.)

If I am correct, then is there a formula (or at least some scaling law) which mathematically relates L, t_{AE}, N_{AE}, and R_{inter}? This seems to be something that can easily be calculated using simulations, so I’d expect that someone must have done this before.

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Any thoughts @swamidass?

Yes that’s right, but the question isnt well posed enough to give a solid mathematical solution.

OK. So are you saying that it’s hard to calculate the probability of A&E being genetic ghosts in something like WLC’s model?

Well, WLC say there were people outside the garden may or may not have interbred with AEs descendants. AE were about 700kya ago to be at the headwaters of humanness.

If they did not interbreed, then AE would not be genetic ghosts.

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What kind of information would be needed?

How about the case of the RTB model, where they specify interbreeding with Neanderthals?

My question was spurred by reading another theologian whose theory basically implies that original sin means passing down a certain set of genetic material.

When he says “genetic”, does he mean DNA? The term “genetic” was used in theology long before it was understood in theological sense. You’d need to clarify if he really means DNA, and in fact knew the distinction between genealogical and genetic ancestry, but still thought DNA was important.

More relevant is that RTB thinks that “humanness” requires some DNA that is unique to Adam and Eve’s lineage, so DNA is connected to their structuralist understanding of the image of God. That does not seem to be a problem, especially if one thinks there is a selective advantage to being fully human.

He was basically proposing that Adam’s first sin resulted in some inherited corruption which guarantees every single one of his descendants are born with a tendency to sin. He used an analogy where the blueprint of a car is corrupted, such that all cars manufactured from the blueprint possess the same defect. (So there is a bit of Lamarckism here too.) I used the word “genetic” to describe the implications of his theory because genes are what we inherited from our parents, and his car analogy certainly invokes that.

He doesn’t specify a model for Adam and Eve to apply to his theological model (nor even a position of the image of God), other than the basic commitment that Adam is the first human being and all humans descend from him. (This is where I think engagement with science could be interesting for his model.)

However, you can see how his theory becomes less tenable if there is sufficient interbreeding between A&E and Neanderthals (for example), then there is no guarantee that original sin is passed down to everyone. That is why I became interested in this question.

It seems that WLC’s model of A&E with no interbreeding would work for his theological model. Otherwise, with a later Adam, perhaps we would need to specify that the corruption is not genetic in the conventional sense, but somehow still passed down to all of his descendants.

There are many things inherited independent of DNA. If “genetic” just means “inherited” to the theologian, than it doesn’t mean DNA.

He and every theologian I’ve read that addresses it specifically, specifies emphatically that they do not think original sin passes by DNA. That just does not make much sense at all.

The things I can think of include social status, wealth, and cultural practices and traditions. Is that what you are thinking of?

Those are all examples of inheritance independent of DNA.

OK, sure. But none of those are part of individual human person as a biological, self-contained organism.* Which is fine - there have been many “social transmission” models of original sin that are proposed, and I don’t think there’s inherently anything prima facie wrong with those. But then this would make physical genealogy no longer relevant. If original sin can be spread via culture, then genealogy in a physical, causal sense might help (because culture is rapidly spread through familial relations) but is not essential. Original sin could also be spread via social interactions.

And of course, there’s also nothing prima facie wrong (or right) with physical genealogy not being relevant to the spread of original sin, but that also seems to make monogenesis and the genealogical science underlying GAE not relevant either.

*Although this reminds me that you might be able argue that the inheritance of culture is analogous to the inheritance of DNA, a la Dawkin’s memetics. From a physical point of view “culture” could be a set of neural connections in one’s brain which is necessarily “propagated” to one’s offspring by family and social activities.

This is not quite right on several levels…

I’m just talking within the context of this person’s theory, of course. I’m not trying to imply that monogenesis might not be relevant for other theological positions.

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Is it a living scholar? Can you ask him?

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It would be interesting to clarify with him what he means.

It’s Oliver Crisp, who wrote some articles for Biologos back in 2015. This lecture contains a summary of his main ideas:

The material from the above lecture is also published in written form here. https://onlinelibrary.wiley.com/doi/abs/10.1111/ijst.12107

Even after reading him twice, I don’t quite understand the details of how his theory would work out in practice. He claims that his theory does not require monogenesis and that it is compatible with different scenarios of evolutionary history, provided certain basic theological commitments, namely:

First, that there was an original pair from whom we are all descended; second, that this pair committed the primal sin which adversely affects all their offspring; and third, that all human beings after the fall of the original pair are in need of salvation, without which they will perish.

He describes this “primal sin” results in a moral corruption or deformity in the human soul which affects every descendant of Adam since they are in the womb:

In keeping with these confessional documents, suppose original sin is a moral corruption that is inherited. It arises early in the development of a first human population, and is passed down by both parents to each successive generation. How does this happen? Here we may turn to the story of Eden as a template. Early in human development, in (say) a first human community, there is some moral breach with God, some primal act of dereliction that introduces a moral corruption to human beings that is inheritable. Call this action the primal sin. On this way of thinking, inheriting a state of sin is not a condition for which the person born in this morally vitiated condition is culpable because (we suppose) a person cannot be held morally responsible for a condition with which he or she is born. It is not the fault of individuals that live diachronically downstream of the first human community that they are generated in a state of moral corruption.

However, it is not clear what the bolded text means, if it is not interpreted in biological or physical terms. Can we interpret it “spiritually”? How can a soul be “deformed”? Is it some sort of “inheritable spiritual substance” which behaves in a very different way compared to physical organs and body parts? The reason I didn’t interpret it as a sort of “socially/culturally inherited moral corruption” is because he emphasizes how this condition applies to each individual person since birth, not the person’s community or surroundings.

As far as the “reformed” position is concerned, there has been strong support from presbyterian theologians already .

Crisp probably does not know about the GAE yet. I wonder if @jongarvey knows him and could reach out to help clarify.

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Unfortunately I haven’t come across Oliver Crisp (though may have read his stuff back in BioLogos days)

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I don’t know if it has been referenced before, but I did find this very interesting paper:

The paper might have the population models you are looking for.

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