The Great Filter

John K Clark (
Mon, 19 Aug 1996 20:46:19 -0700 (PDT)


I an sending this to both the Extropian and Transhuman list because I think
everyone should read Robin's fine article.

Robin Hanson has published a very interesting article on the Web called
"The Great Filter" (
Robin argues, correctly I think, that if intelligent life is not somehow
destroyed then eventually it will explode into the universe and make it's
existence obvious even on the Cosmological scale. He lists 7 stages that
must happen before this happens.

1. Reproductive something (e.g. RNA)
2. Simple single-cell life
3. Complex single-cell life
4. Multi-cell life
5. Animals with big brains
6. Where we are now
7. Explosion

Robin then notes that there is not the slightest evidence for intelligent
life except on the earth (The Fermi Paradox) so one of these stages must be
very difficult to pass through. If the roadblock happens somewhere in the
first 6 stages then we've already made it through and there is reason for
optimism. If the trouble is between stage 6 and 7 then be afraid, be very
afraid, most don't make it through. If this is the case then the problem is
probably not one we've imagined, probably not one we can imagine. If the
recent talk about bacteria on Mars turns out to be true that means the first
2 stages are easy to get through, not a good sign.

in spite of this I have a hunch the bottleneck is in the first 6 stages, I
sure hope so. I want to talk a little about stages 5 and 6. Arthur C Clarke
wrote a short story about a race of noble horse like beings who had
developed a complex and beautiful philosophy, possessed profound mathematical
ideas, and were more intelligent than humans, but they had no technology
because the had no hands. Dolphins and whales in our world have very large
brains, but not only are they lacking hands they have other handicaps they
must overcome. If you live underwater you can't know anything about fire, an
essential ingredient in technology. Also, It's hard enough to deduce the
basic laws of Physics living in an atmosphere, most of the laws are only
really obvious in a vacuum, surely a bizarre concept for any life form
living in a thick heavy medium like water. " What do you mean objects move
in a straight line at a constant speed unless acted upon by an outside force?
What do you mean all objects fall to earth with the same acceleration
regardless of size of weight? Any fool can see that's not true."

Elsewhere intelligent beings could have other problems. It took an
Isaac Newton, who has a good claim on being the smartest man who ever lived,
to deduce the laws of gravitation from the motion of the planets,
but Newton had it easy. The sun is unusual, it has no companion,
most stars consist of 2 or more suns of roughly equal mass revolving about
each other. The orbit of any planets in such a system would be so horribly
complex that even Newton wouldn't be smart enough to figure it out.

John K Clark

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