In article <dIidnfKx3voU5T7VnZ2dnUVZ_hKdnZ2d@comcast.com>,
 "K_h" <KHolmes@SX729.com> wrote:

For life to start, a molecule must arise that can make approximate copies of 
itself.  Once that happens then natural selection can work its magic.  But a 
molecule that can make approximate copies of itself must be a fairly 
sophisticated nano-machine being comprised of dozens, if not hundreds, of 
molecules and it must arise via inorganic and non-evolutionary processes.

There are actually two schools of thought on this. The other one is 
called metabolism-first, and holds that a network of chemical reactions 
that can transport energy is easier to establish and thus precedes the 
self-replication. (I didn't stay at a Holiday Inn, but I do read 
Scientific American.) 

Another thing you should consider when discussing biochemistry is the 
chemist's definition of the word organic. Since we care discussing 
biochemistry, I will ask the question in that semantic context: why do 
you exclude inorganic molecules and processes? 

From the study of DNA and genes, it is known that all life on the Earth has 
a common origin (undoubtedly from a molecule of the aforementioned kind). 
Since Earth is a life friendly planet, why hasn't another molecule (of the 
aforementioned kind) arisen?  If it had, then life on the Earth would have 
organisms with two different molecules for genetic codes: DNA and something 
else.

Any such molecules that showed up late would get eaten. 

This suggests that the formation of such a molecule is a very rare event. 

No, it suggests that once a particular chemical basis of life gets 
established, another one won't. 

Unfortunately, that pretty much negates the rest of your argument.

-- 
Timberwoof <me at timberwoof dot com> http://www.timberwoof.com
People who can't spell get kicked out of Hogwarts.