The Great Filter

Eric Watt Forste (
Fri, 30 Aug 1996 20:47:59 -0700

At 10:14 AM 8/30/96, wrote:
> Eric Watt Forste suggests that the great filter is in the
> step to advanced tool use. What about the objection that
> this step was completed relatively _shortly_ after the
> humanoid monkeys came into existance?

I suspect I wasn't making myself very clear, but what I had in mind was the
step leading to language, which vastly accelerated memetic (or in other
words, conceptual, or cultural) evolution so much that even though there
are transmitted behaviors of nongenetic origin in other species, they play
a drastically smaller role in the development of other species than they do
in the development of our species.

Since spoken language itself leaves zero fossil evidence, it's very
difficult to date this particular step with any precision. It seems
possible that cetaceans *may* have had this (I've done no research, I've
just heard the claims) long before we did, but were hampered from making
the same use of it by their lack of hands. If cetaceans do have full-on
language (whatever that means), then that would pretty much blow away the
candidacy of language-use for a significant part of the Filter.

The candidacy also might be affected by the extremely limited research
being done on the ability of other pongid species to transmit sign-language
from parent to child without human intervention. I have done a bit of
research on this, and language use by nonhuman apes is really not
comparable, at least from the point of view of the role it could play in
conceptual evolution. But if unassisted parent-child transmission of
signing is stable and self-propagating, I'd probably want to back down on
proposing language use as a big part of the Filter. Then again, it's
*possible* that language use originated with a common ancestor of all the
pongid apes, and that Homo sapiens was the only pongid species to retain
it. It's probably very computationally expensive, and therefore would be
selected against in most situations until it got well off the ground.

I hesitate to put much credence in attempts to date the origin of spoken
language by assuming that it closely correlates with some other more
readily datable behavior, such as use of stone tools. It might have long
preceded that, or it might even have come long after. I hope Simon! is
listening in... are there any linguists in the house? But the last bit of
paleolinguistics I read (a long time ago) was pretty vague on the dating of

At 3:32 PM 8/30/96, Robin Hanson wrote:
>[...] or maybe the hard step
>was some special organization of mammal brains relative to bird brains.
>Is there an important different of organization here?

This is what I've been thinking, though I'd say verbal brains relative to
nonverbal brains. The brain is poorly understood and leaves little fossil
evidence other than evidence of size. Language in and of itself is prima
facie evidence for an important difference of organization between human
and nonhuman brains.

Is it possible that we passed through most of the Great Filter during the
glacials? Just yesterday, as it were?

Eric Watt Forste <>