[extropy-chat] Dark matter and ET

[Eliezer S. Yudkowsky]

Robin Hanson wrote:
> At 08:59 PM 7/14/2005, Eliezer S. Yudkowsky wrote:
> 
>>> It is a subtle question what exactly the goals of alien civilizations 
>>> would be, and different goals lead to different computational
>>> priorities.
>> 
>> I don't see why different computational priorities should affect the 
>> material prediction, valid for an extremely wide range of goal systems:
>> that superintelligences should convert available matter into 
>> configurations more useful than stars, which generate massive amounts of
>> entropy without performing any computations...
> 
> Robert Bradbury assumed that each alien civilization had a fixed chunk of
> matter and repository of free energy, and wanted to extract as many CPU
> cycles out of those, no matter how long this took, and were not very 
> interested in exchanging I/O with other civilizations.  These assumptions
> lead to very different optimal computation configurations than, for
> example, a rapidly expanding civilization that only cared about computation
> in order to support that expansion.  Such an expanding civilization would
> be much less patient, would want lots of I/O regarding colonization
> targets, and would want the computation to be located near in space and
> time to those efforts.

That seems to be based on a frequent-life model... which I suppose is 
appropriate, if one thinks there is a Fermi Paradox to explain.  I had been 
thinking more in terms of trying to grab as large a 3D sphere as possible 
before running into the borders of another expanding species.  If we assume 
that intelligent life originates at a sufficiently fast rate, without a 
gradual start in the maturation of worlds, that, even traveling at lightspeed, 
sufficiently many intelligent species mature simultaneously that each galaxy 
is divided up into many volumes... hm.  I suppose simple discount rates might 
then have an effect on the expected brightness of galaxies, even though other 
aspects of the utility function are irrelevant!  In that sense, I accept the 
correction.

Even so, what use are stars?

And with life 3.85 billion years old on Earth, and the Milky Way 100,000 
lightyears across, how likely is it that more than one intelligent species 
arises in a galaxy before the first species takes over the whole galaxy?

-- 
Eliezer S. Yudkowsky                          http://singinst.org/
Research Fellow, Singularity Institute for Artificial Intelligence