On Wed, 30 Jul 2003, Tony Sivori wrote:

I still say the obvious answer is the right answer.

We can be sure they are out there somewhere (perhaps nowhere close, not even
within many hundreds of light years) because the universe is so big, and
cosmically speaking our galaxy, our star and our planet are nothing
extraordinary. So to think we are the only intelligent life in the universe
runs counter all the growing evidence that the Earth is of no special
significance.

The reason they aren't here (or haven't been heard from) because the
universe is so big.

It is the simplest explanation that accounts for all the facts.

It is indeed, but it runs afoul of two emotional shoals that generate lots
and lots of rationalizations.  First of all, the distinctly American
fetish that endless expansion would automatically appeal to everyone,
everywhere.  And secondly to the much more widespread need so many people
have to be so very special, the center of the Universe, right there under
God's eye.

It's been a really bad millenium for people like that, what with Mongols
riding in out of nowhere, and all those new continents, and Copernicus,
and Hubble (remember that less than a hundred years ago "the
universe" referred to what we now know as our galaxy).  There are many
directions in which you can take a long-exposure image and more of the
spots seen are galaxies than are individual stars.

Some people find this universe utterly inspiring.  Others flinch away from
it, and some of the flinchers are even people with scientific credentials,
if not scientific attitudes.  One demonstration of this can be had from
the classic Drake "equation".  Originally just a framework for organizing
guesstimates and suggesting directions for investigations, it pulled a lot
of order-of-magnitude guesses out of the air for purposes of
demonstration.

Well, we now have data to constrain several of the original Drake guesses
more tightly.  And in _every case_ where more data has come in on Drake
equation elements, the change has been in favor of _higher_ probabilities
of life and intelligent life.

In the last fifty years, we've learned that the attributes that add up to
intelligence are more widely spread in the animal kingdom, and that
suggests that parallel evolution of intelligence could come more easily
that we thought before.  In fact, the likeliest scenario is that a
moderate level of intelligence evolved in several hominid species, and the
Cro-Magnon types got a leg up on the others and proceeded to maintain
their lead by the pleasantly direct approach of having all their rivals
for dinner.

We've learned that, far from being rare as the original Drake formulators
assumed, planets are common around other stars.  To such an extent that
the limits seem to be our detection abilities more than any actual
shortage.

The origin of life in liquid-water zones seems far more probable now than
it did sixty years ago.  Every decade has brought more examples of how the
interstellar medium is a rich source of precursor materials, and how those
precursor materials tend to self-organize into more complex structures
that a hundred years ago would have been regarded as the exclusive
products of living things.

The original Drake estimate was for what, 88,000 intelligent neighbors in
our galaxy?  The back of my envelope suggests that this should be revised
upward, towards something more like a million, if we just change the
numbers in response to actual new data where it's become available.

This, of course, makes the Fermi paradox worse, in the same
proportions.  But the anti-Copernican crowd reacts to each new bit of hard
data with greater emotional desperation, and it shows in the way Occam's
Razor gets so neglected in some of their proposals.  Handwaved planetary
orbital changes worthy of Velikovsky and Hoerbiger, but serving to make
stable orbits in the liquid water zone less plausible.  Panspermia,
because it reduces the number of times life needs to arise independently,
and allows "creation" to be special rather than routine.

What's the answer to Fermi's paradox?  I don't know, but my personal
guesses suggest that by the time a civilization from an Earthlike planet
learns enough spacefaring skills to make successful sublight leaps to
other systems, they may not care that much about Earthlike planets any
more.  For folk like these, the really signifigant wealth and
opportunities may lie between the Kuiper Belt and the asteroid belt, or
local equivalents.  If so, each new system might offer opportunities for
(wealth, adventure, whatever turns alien explorers on) far more extensive
than those to be found on any single Earthlike world.  This might serve to
knock an order of magnitude or three off the Fermi assumptions about how
fast a colony spawned colonies of its own.

Conrad Hodson