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From: dubois@uwmacc.UUCP (Paul DuBois)
Newsgroups: net.origins
Subject: Re: I Myself am Left-Handed
Message-ID: <567@uwmacc.UUCP>
Date: Sat, 15-Dec-84 16:06:35 EST
Article-I.D.: uwmacc.567
Posted: Sat Dec 15 16:06:35 1984
Date-Received: Mon, 17-Dec-84 03:47:20 EST
References: <491@uwmacc.UUCP> <418@digi-g.UUCP>
Distribution: net
Organization: UW-Madison Primate Center
Lines: 74

>>> Creationists
>>> seem to assume that there is ONE and ONLY ONE combination of proteins,
>>> amino acids, etc. that are capable of supporting life, when this is not
>>> the case.
>>
>>This is in fact not true, and the statement betrays an ignorance of
>>two things:
>>
>>(i) some creationist arguments proceed on the basis that
>>many biological combinations would be suitable.  I will not present
>>the argument, but the idea is generally that even an astronomical
>>number of suitable combinations would be too few to give any sort
>>of reasonable probability, because of the size of the sample space.
>>(This is not to defend such arguments, however; they often suffer
>>fallacies in the assumptions.)
>>(ii) [deleted, irrelevant -- pd]

> The original argument implied, by the probabilities quoted, exactly
> ONE combination of (acids|proteins|etc) producing life.  If an argument
> comes along that allows for 'an astronomical' number of combinations,
> yet still calculates the origin of life to be near zero, there are other
> arguments waiting in the wings.  (e.g. the fact that not all pre-organic
> and organic chemicals form with equal probability, which is blithely
> ignored by most arguments I've seen in this newsgroup).

The original argument may have implied it.  Your commments were
phrased in terms of creationists in general.  My remarks stand.

>>> (They are also impressed by the fact that almost all of the
>>> naturally occuring assymetrical organics have the same "handedness" (L
>>> instead of D), while experimentally 'cooked up' ones are an even mix of
>>> about 50% L, 50% D.  Give me a break!  They are designated L or D by
>>> HUMANS, there is no intrinsic left- vs right-handedness in the molecules!
>>
>>I would appreciate it if Mr. Leroy would explain what he is trying
>>to show here.  The labels may indeed be arbitrary, but reversing
>>the labels changes neither the near-homogeneity of handedness of
>>biological organics, nor the racemic nature of experimentally
>>produced ones.

> Ahem.  Exactly.  The labels are arbitrary.  Almost all of the naturally
> occuring organics are designated L.  They could all be designated D.
> They could be designated L if they had an odd number of hydrogen atoms,
> and D if they had an even number of hydrogen atoms.  They could be L
> if discovered on Mon/Wed/Fri, and D if discovered on Tues/Thur/Sat/Sun.
> Scientists, being kind to aspiring biologists, named them consistently.
> Why are creationists amazed that 'all' of the natural organics are L???

Let's see if we can communicate, we're missing each other somewhere.
When I talk about arbitrariness of labelling, I mean the *group*
of L-amino acids as opposed to the *group* of D-amino acids.  The
labels of the groups could be reversed and it would make no
difference - the near homogenity of handedness of biological organics
would be preserved.

By your comments, particularly about labelling on the basis of day
of discovery, I assume (perhaps incorrectly?) that you mean for any
given *amino acid* the two forms could be labelled arbitrarily.
This would render the labels meaningless, since there would be no
common properties among the elements of each group.

Asserting that there is no intrinsic left- or right-handedness
of the molecules is in one sense true.  But that is hardly the
same thing as saying there is no common property.  There is.
All of the L-amino forms follow the CORN law:  when one looks down
the bond joining the H-atom to the alpha-carbon, one can read off,
in clockwise order, the *CO*OH group, *R* group, and *N*H_2 group.
A shared structural characteristic:  not arbitrary.
-- 
Paul DuBois		{allegra,ihnp4,seismo}!uwvax!uwmacc!dubois

"I will sing unto the Lord as long as I live:  I will sing
praise to my God while I have my being."
					Psalm 104:33