The Great Filter

Robin Hanson (
Wed, 21 Aug 96 11:12:31 PDT

Eric Watt Forste writes:
>the jump from simple to complex single-cell life. Am I safe in
>assuming that this means the same thing as the jump from prokaryotic
>to eukaryotic life?


>The jump from prokaryotic to eukaryotic life, then, would be a mutation or
>a sequence of mutations that resulted in a nonlethal total failure of the
>prokaryotic immune system. This notion seems sufficiently paradoxical to me
>that I'm content, for the time being, to identify the jump from prokaryote
>to eukaryote as the Great Filter.

Sounds plausible to me, but I don't know this field very well. I
worry, though, in actuality cells might have slowly gone through many
evolutionary steps over this period, steps that our fossil record and
tools might be too coarse to make out. It might just look like one
big step because that's all we can see. (Is this what William Lerette
meant by his crypic comment?)

>The other possible counterargument, as Robin points out, is that the
>mutation took only two billion years (on Earth) to happen. But if the
>prokaryotic panspermia idea is right, and there are prokaryotes as thick as
>mud throughout the universe, then we could say that the Great Filter
>mutation took more like ten to fifteen billion years to take place,

Again, I'm no expert, but from reading Crick I got the strong
impression that prokaryotic cells are much less robust to extreme
environments, and much better tuned to the particulars of Earth now.

Sigh - guess I need to read up on yet another relevant field to this
very interdisciplinary subject. :-)

Robin Hanson