From: Robin Hanson (rhanson@gmu.edu)
Date: Tue Jul 22 2003 - 20:12:20 MDT
I recall many discussions when I was previously on the list, with Robert
taking the same position as he's taking now. I'm not sure the debate has
progressed any, and I know I don't have the time-stamina here now to talk
on this for as long as such discussions usually go, but since many/most on
the list now probably haven't read or don't recall all those old
discussions, I'll quickly review my position.
The key empirical puzzle is that we can do a decent job explaining
*everything* we see beyond Earth using the hypothesis that it is all
completely dead, and that life here was never influence by life
elsewhere. Of course there's a great deal that we cannot see, but there is
also huge amount that we can see. So if there is
life/intelligence/civilization out there it isn't having much of an
influence on the things we can see.
This empirical fact is in conflict with theoretical expectations that
life/etc typically looks different from death, that it tends to spread to
available niches (which include the things we can see), and that with time
it tends to become more "advanced" by accumulating innovations. The more
advanced it becomes, the easier it can spread and the more ability it has
to look different from death. It should have had billions of years to
advance. Many of us picture our descendants soon acquiring the ability to
colonize the uncolonized universe and make a big impact on what it looks
like.
There are several ways to resolve this puzzle, though none of them seem
particularly attractive. There may be no life/etc out there, or it may all
be primitive, so that life is extremely unlikely to make the transition to
the advanced level at which we soon hope to be. Contrary to all we think
we know about physics, it may be physically very hard to spread, so that
even very advanced life is effectively isolated. Or perhaps advanced life
or it spreading wasn't physically possible until very very
recently. Finally, the universe may be under the unified control of a very
ancient advanced power which enforces a rule that implies that the sorts of
things we can see must look dead.
Robert Bradbury has proposed that advanced life naturally acquires
preferences that make it want to become invisible and not want to
spread. It seems to me that in doing so Robert has taken his desires and
projected them as the desire of most/all advanced life, and in the process
fundamentally misunderstood evolution. Short of a unified control over the
universe there is simply no such thing as taking over evolution on the long
timescale. And given that evolution rules, the only natural preferences
are those that result in the "most" progeny, regardless of other consequences.
Robin Hanson rhanson@gmu.edu http://hanson.gmu.edu
Assistant Professor of Economics, George Mason University
MSN 1D3, Carow Hall, Fairfax VA 22030-4444
703-993-2326 FAX: 703-993-2323
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