Which fallacy is it?

Hi Andrew
The reasoning behind your assertion remains unclear. He is simply making an argument given genetic entropy as a working hypothesis that survival of an ancient living organism with small populations is unlikely. LUCA is a hypothetical construct so there is no basis to claim he is committing the TSS.

The sub-argument about who committed which fallacy can have a home here.

If we are going to talk about fallacies, I’ll just point out that LUCA is a hypothetical individual. And individuals don’t go extinct.


AFAICT including contradictory attributes in your terms (“first last universal common ancestor”) is too ridiculous to qualify as a fallacy.

  1. That’s a “those can’t be craters on the moon if there’s an invisible field preventing meteorite impacts” argument. There isn’t such a field, and we know that because we can see craters.

  2. Genetic Entropy isn’t real. Literally zero evidence for it.

  3. And there’s no reason to think the population of LUCA was ever small enough for something like error catastrophe to be a problem. Of course since we all now exist and descent from LUCA, it clearly wasn’t (see the craters analogy).


No, LUCA is a hypothetical population.

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