From: dietz@cs.rochester.edu (Paul Dietz)
Subject: Re: Entropy of the Universe, (was Re: Genesis - fact or fiction)
Organization: Computer Science Department University of Rochester
Distribution: na
Date: Fri, 21 Aug 1992 23:11:50 GMT

Come on, people.  We know "creation science" is a contradiction in
terms, but that's no excuse to present bullshit about chemical
evolution.  Creationists have correctly targeted this as a seriously
deficient area (not that that lends any support to biblical
fundamentalism, of course).

Frankly, the existing theories of biogenesis, including many of
the "party lines" parroted here, are at best very dubious.
Let's consider some slogans and their refutations:

1. "With millions of years and cubic miles of solution, even
  rare events are bound to happen".

   This is a very weak argument against the combinatorial
problem.  Millions of years and thousands of cubic miles of
water don't tack very many zeros onto the number of trials.
The full complexity of the modern cell's machinery dwarfs
any random search that could be made by any reasonable system
that could fit in the observable universe.  So, one must
postulate a nonrandom process -- a route "hardwired" into
the laws of chemistry -- that leads to self replication.


2. "The molecules of life have been shown to form naturally."

  Actually, only *some* of the molecules of life have been
shown to form naturally (specifically, some of the amino acids,
some bases, some sugars).  Unfortunately:  (a) they are formed
in very low concentrations, (b) they are mixed with large numbers
of other, biologically irrelevant isomers, (c) some of the experiments
showing their formation require unreasonable conditions (concentrated
formaldehyde, for example).

  More problematically, very important molecules like nucleotides
(the building blocks of RNA and DNA) have never been shown to be
produced in a realistic prebiotic environment -- let alone RNA and
DNA.

  The formation of biologically relevant molecules can't be taken to
be all that interesting.  It just shows that life uses some molecules
that are rather simple and stable, and that therefore also tend to be
produced by more undirected physical processes.  Is this surprising?


3. "Self reproducing molecules have been demonstrated in the
  laboratory"

  Yes, but never with plausible prebiotic molecules, or in solutions
containing reasonable concentrations of contaminants or isomeric
monomers that would be expected to jam replication.

  The famous experiment showing replication of RNA molecules in
solutions of ATP, etc. is irrelevant to biogenesis; ATP is an
unreasonable molecule to appear in a "prebiotic soup" (it is too
unstable), never mind appear in a pure form.


4. "Natural selection gets around the combinatorial problem"

  This ignores the fact that natural selection can only occur in
systems that already can copy and express genetic information of some
kind.  Moreover, the requirements for copying accuracy are stringent.
An error rate of 1% means the maximum genome size is only about 100
bits.

  The central problem in biogenesis is the "complexity barrier" that
exists between demonstrated prebiotic systems and those systems that
can undergo selection.  This barrier is enormous, and has not been
convincingly bridged.

---------------

The conventional "warm ponds of primordial soup" scenario is a useful
*working hypothesis* (it at least suggests experiments), but to
pretend that it has been proven to be true is scientifically
fraudulent.

	Paul F. Dietz
	dietz@cs.rochester.edu