From: dietz@cs.rochester.edu (Paul Dietz)
Newsgroups: sci.space
Subject: Re: ETs and Radio
Date: 29 Jul 92 20:23:12 GMT
Distribution: sci


I'm of the opinion that it has *not* been shown that the origin
of life is likely.

One problem with the arguments that "look, we can make X, Y and
Z in the lab, which have many of the features of life" is that
having many of the features of life is not enough.  Close doesn't
count here.  A good example is Fox's protenoids.  They look like
cells in that they are spherical and enclose a volume.  They have
multiple charged moieties that show generalized, nonspecific catalytic
function (just like any random protein will).  But are they "life"?
No, because they lack the crucial property of holding and expressing
genetic information.

One might call this unfounded optimism the "Coke Contest Fallacy".
The Coca Cola Company periodically holds contests where you have to collect
bottlecaps spelling a certain word or phrase.  As one starts to
play, hope abounds as more and more letters are found.  But at the end,
one letter never seems to show up, and the game period expires without
you winning.  That last letter, of course, is the one that controls
how many winners there were.

The analogy to origin of life is that certain common features, like
the fact that partially hydrophobic proteins form vesicles, will pop
out early.  This doesn't mean that life is much more likely, since a
rare, difficult and rate controlling event would be hard to discover
in the lab, by definition.

Some very basic problems remain in origin of life research.  One of
the most basic is:  "how do polymers formed by condensation (i.e.,
water removing) reactions form in an aqueous environment (where the
excess of water should drive the reaction the other way)."  As far
as I know, this has not been solved.  Life today solves this problem
with the use of complex enzymatic machinery and liberal expenditure
of ATP and other phosphorylated molecules.  Another is "how did
the bases of RNA form?"  The environment for the formation of adenine
and so on seems to be quite different from that forming amino acids
or the sugars that form the backbone of nucleic acids.  Yet another is
"how did the genetic machinery, for replication of the gene, and for
its expression, get started".  No convincing scheme has been presented,
although much imagination has been applied.

Perhaps we'll discover, some day, a simple path hardwired into chemistry
that leads to life.  Or, perhaps, if life really does require an accident,
the field will continue to produce hopeful but ultimately sterile suggestive
results.  I suspect the answer may not really be known until our
descendants explore many other stellar systems, or come into contact
with aliens who have.

If life really is somewhat rare, the place to look for ET signals is from
distant galaxies, broadcast by pan-galactic supercivilizations.  These
civilizations could be far enough away to evade the Fermi Paradox, since
ships in an intergalactic colonization wave would likely not travel straight
out from the starting point, but rather go to nearby galaxies, giving
a colonization wave speed significantly less than the speed of light.

	Paul F. Dietz
	dietz@cs.rochester.edu

	
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