The Great Filter

Robin Hanson (
Fri, 30 Aug 96 21:40:20 PDT

Eric Watt Forste writes:
>>[...] 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?

As Nicholas said, its implausible that a very hard step, such as
language, happened so soon after its enabling large brains prior step,
unless some special very usual environment was involved (and its hard
to see what that could be).

The step could have happened long ago though, if it was something
basic about mammal brains, that just needed time to flower into us.
We don't need fossil evidence for this - looking at today's mammals
and birds is good enough. Is there anything lacking in bird brains so
they couldn't have become like us, had they had hands and large social

Robin Hanson