On Thu, 13 Mar 1997 22:08:39 -0600, Glenn Morton wrote:
[...]
GM>The new report used an amino acid that does NOT appear in any
>terrestrial living form and it was non-racemic and preferentially
>left-handed. Since this particular amino acid is not incorporated
>into a earth species, it cannot be contamination by terrestrial
>sources because no terrestrial creatures use it.
Agreed, but it still could be a terrestrial *non-biological* amino
acid. Indeed if "no terrestrial creatures use it", what is its
relevance to the origin of life on Earth? It does not prove that
non-racemic mechanism exist in space because it is already known that
such mechanisms exist:
"Circularly polarized sunlight, for example, leads to a selective
photochemical decomposition of chiral molecules...Bremsstrahlung
radiation generated when polarized beta rays interact with matter has
been found to destroy the enantiomers of amino acids at slightly
different rates...Radiation from cobalt-60 has also been found to
decompose D-tyrosine more rapidly than L-tyrosine...Interaction with
chiral surfaces. Probably the most reasonable explanation for chiral
discrimination has been the idea that chiral mineral surfaces may
have played an important role. For example, one could imagine that
stereoselective polymerization of amino acids could occur on
kaolinite, or bentonite surfaces. Alternatively there could have
been stereoselective adsorption to chiral crystalline minerals, such
as quartz, or Iceland spar" (Croft L.R., "How Life Began",, 1988,
p62)
SJ>Glenn's "unknown to us at this moment" seems to indicate that he
>believes that this "mechanism" will become known to us in the future.
>I ask on what scientific evidence Glenn bases his belief on?
GM>The FACT that a nonracemic, non-terrestrial form of amino acid was
>found in a meteorite. If God himself made this then there is no
>mechanism. But I don't think God did that.
I agree that "God" is unlikely to have supernaturally made such a
weak example, especially since there are already *known* natural
mechanisms that can produce non-racemic amino acids. But why
then should a future "unkown" mechanism be postulated?
GM>Croft further points out that one cannot ever be certain that the
>contents of a meteorite did not originate on earth:
[...]
GM>You can be absolutely certain that the NON-TERRESTRIAL amino acid
>was not picked up from earth life.
Agreed, but not "absolutely certain" it is non-terrestrial. All the
authors of the paper said was that the amino acid "has not been
reported to occur in terrestrial matter" (John R. Cronin and Sandra
Pizzarello, "Enantiomeric Excesses in Meteoritic Amino Acids,"
Science 275 (February 14, 1997):951-955, p. 951). It is therefore
still possible that the amino acid was terrestrial, but as yet
unreported. I would be surprised if science knew every obscure amino
acid on Earth.
SJ>Croft actually provides an alternative explanation for the amino
>acids in meteorites:
[...]
GM>The Science article uses none of the above mentioned amino acids
>so their conclusion does not apply.
It does as far as the amino acids that are found in terrestrial
living things! The amino acid that Cronin and Pizzarello are writing
about is not.
[...]
GM>No, all that has to be shown is that a non-terrestial source
>created an optically active amino acid not found in life. But as a
>matter of interest, the authors of the Science article suggest that
>polarized light has had an effect on the amino acid formation in the
>Murchison meteorite.
Well what was all the fuss about there being "a mechanism (unknown to
us at this moment) which is quite capable of producing non-racemic
amino acids" and "Some of these results show that something in space
was able to produce 70-90% L amino acids...I don't know the mechanism
but there is one"?
SJ>See above. Even if it is shown that the L-amino acids were
>extraterrestrial, it still would not show that they were the result
>of a natural process unless that process is known. Science has
>tried every conceivable way to make L-amino acids naturally, but has
>drawn a complete blank.
GM>This is not true. Using L-templates creates L forms. You can't
>say science has drawn a complete blank.
I said "naturally". A human intelligent designer using "using
L-templates" is an analogy of *creation* not naturalistic evolution:
"Of course, optically pure laevorotary amino acids can he produced in
a laboratory. I have synthesized by the kilogram optically pure
alanine, as well as a-amino-buyric acid and many other similar
compounds, but never by chance. With the aid of know-how and a prior
asymmetric center, this is easily accomplished, but never through
chance (non-know- how). Complicated chemical processes are required
to carry out this synthetic puzzle. To obtain resolution, a
previously established optically active center is required, which is
of course never produced by chance. Any educated chemist will smile
if chance is mentioned in this context." (Wilder-Smith A.E., "The
Natural Sciences Know Nothing of Evolution", 1981, p26)
SJ>OK. But it should be remembered that this meteorite is "4.5
>billion years" old, and it may be that these "amino acids" were once
>"found in terrestrial organisms" but have since become extinct.
GM>What is your evidence for this? since we don't have ancient amino
>acids from 4.5 billion years ago, how do you know?
I didn't say I "know". I said "it may be".
>GM>"n each case, the researchers found .
[...]
SJ>Interesting. If it was 50 or more "percent", I would find it
>more convincing.
GM>It was as much as 59 percent left handed forms so why don't you
>find it convincing
I agree that my "50 or more "percent" is confusing. But "an excess
of the left-handed form of the amino acid, ranging from 2 to 9
percent" is only "from 2 to 9 percent" variation from the normal
racemic 50%. What is needed is 100% "left-handed form of the amino
acid":
"It must be borne in mind that for the synthesis of life to occur,
practically 100% optical purity is required in as many as 20
different amino acids. Never has an optically pure specimen been
obtained by any inorganic random reactions. For these and other
reasons, spontaneous biogenesis has remained an experimental
impossibility to the present day." (Wilder-Smith A.E., "The Natural
Sciences Know Nothing of Evolution", 1981, p25)
GM>other than the fact that you don't want evolution to have any
>evidence in its favor?
What I "want" is irrelevant. The fact is that 52-59% L-handedness in
an amino acid that is not among the 20 found in living things is
interesting, but it is hardly much "evidence" in "favor" of
"evolution".
But I do find it interesting that Glenn does not like me to have a
sceptical attitude toward "evolution", when that is supposed to be
the scientific attitude in every other area of science. It tells
me "evolution" is more than a scientific theory to Glenn - it is
part of his religion:
"Certainly, historically, that if you look at, say, evolutionary
theory...it's certainly been the case that evolution has functioned,
if not as a religion as such, certainly with elements akin to a
secular religion. Those of us who teach philosophy of religion
always say there's no way of defining religion by a neat, necessary
and sufficient condition. The best that you can do is list a number
of characteristics, some of which all religions have, and none of
which any religion, whatever or however you sort of put it. And
certainly, there's no doubt about it, that in the past, and I think
also in the present, for many evolutionists, evolution has functioned
as something with elements which are, let us say, akin to being a
secular religion." (Ruse M., "Nonliteralist Anti-Evolutionism: The
Case of Phillip Johnson", 1993 Annual Meeting of the AAAS, Symposium
"The New Antievolutionism", February 13, 1993)
SJ>If there was a natural process in space that can bias amino acids
>acids towards L-handedness, one why would evidence of it only be
>found "in the Murchison meteorite"? I would have thought that this
>suggests that the possibility of some unusual terrestrial
>contamination cannot be ruled out.
GM>It isn't only found in the murchison meteorite, but this type of
>meteor, a carbonaceous chondrite is a rare meteorite and only
>represents about 3 percent of all meteor falls. While rare, the
>Murchison is not alone...
I would have thought that "3 percent of all meteor falls" would add
up to a lot of meteorites!
>GM>"The finding of enantiomeric excesses in amino acids indigenous
>to the Murchison meteorite constitutes the first natural evidence
>for the operation of an abiotic process for enantiomeric enrichment.
SJ>I cannot see how they can draw this conclusion. It could equally
>be "evidence for the operation of a" *biotic* "process" on Earth or
>in space "4.5 billion years" ago.
[...]
SJ>Even granted all the above, this may still be something that the
>Intelligent Designer prepared and used. It is the planning,
>preparation and putting together that is the mark of Intelligent
>Design.
GM>Nobody is denying this Stephen.
If Glenn really believes in "planning, preparation and putting
together", then he is not believing in "evolution" in the same sense
that science uses it-he is believing in a form of mediate *creation*
not "evolution".
GM>I don't know why you think TEs on this list are denying God's
>design.
Good. I'll remember that next time I see "TEs on this list"
attacking what they somewhat contemptiously refer to as "the design
crowd".
God bless.
Steve
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