poly: Anthropic => Aliens like us?

Apparently various fundamental physics parameters look
suspiciously tuned to allow life like us. For
example, certain nuclear resonances and cross sections
look tuned to allow stars to produce lots of Carbon.

An anthropic analysis would suggest that these parameters
are different in different parts of a "multiverse", and
it is no coincidence that we, Carbon based life, live
in a place in the multiverse tuned for Carbon.

It occurs to me that this could be taken as evidence
*against* non-carbon based life where our physics
parameters apply. After all, if most generic untuned
places were friendly to life, then we shouldn't
expect to be in a place tuned for our kind of life.
And if most places are unfriendly to life we should
be very suprised to see our place happen to be tuned
for two different kinds of life.

A similar argument would apply to any other way in which
the universe appears tuned for us. If this place is
tuned to make planets, for example, then we shouldn't
expect to find life here that didn't start on a planet.

This strikes me as the sort of argument that may have
been already made. Barrow & Tipler make it?

Robin Hanson
hanson@econ.berkeley.edu http://hanson.berkeley.edu/
RWJF Health Policy Scholar FAX: 510-643-8614
140 Warren Hall, UC Berkeley, CA 94720-7360 510-643-1884
after 8/99: Assist. Prof. Economics, George Mason Univ.
Received on Fri Mar 12 14:14:53 1999