Hello
It is of course OK to be skeptical of claims of life elsewhere in the
Universe. Carolus Linnaeus, the founder of biology, to avoid considering sailor
tales (and later Bigfoot, Yeti, and Loch Ness claims) insisted on a type
specimen. The controversy over ALH 84001 boils down to whether the truncated
hexaoctahedral magnetite crystals found constitute a type specimen, or were
they produced abiotically on Mars (they are not produced abiotically on Earth).
It is always possible to posit by some Rube Goldberg-like mechanism am abiotic
origin to almost any trace biological evidence. Insisting that evidence
absolutely not have any abiotic orgin possible under any circumstances is a
hurdle too high and in my view, too illogical. That is the difficulty.
Of possible use in this brouhaha is Rudolf Carnap's theory of logical
probability assigned to theories. An accepted type specimen is of course, proof
positive; the probability of extraterrestrial life then is 100%. But the
probability is still nonzero that microscopic life indeed does exist under the
frozen lake of Elysium. Assigning probability to a theory is a difficult task,
and the popular media folks are totally clueless on the concept. IMVHO, the
evidence is such that it is more probable microscopic life exists/existed on
Mars that not.
But Carnap's ideas, endorsed by Martin Gardner, will be helpful in this
situation. An outline of them is found in Carnap, R. Philosophical Foundations
of Physics, Basic Books, London 1966. edited by Martin Gardner.
Francis Graham
Kent State University
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From: [email protected]
[[email protected]] On Behalf Of dorifry
[[email protected]]
Sent: Tuesday, August 09, 2011 2:49 PM
To: [email protected]
Subject: [meteorite-list] More evidence of building blocks of DNA in
meteorites
Hello fellow Listerians:
It's hype, just like the sketchy arsenic-based life forms and the imaginary
Martian fossils. First off when you say DNA, most people think of a biotic
double helix just like we have in the nuclei of our cells. Components of
DNA is an entirely different thing, like maybe a little bit of a rung from
the DNA ladder. And the same nucleobases plus some hypoxanthine and xanthine
were found in the surrounding ice and soil samples near the other
meteorites. Sounds a lot like terrestrial contamination. Maybe the analog
compounds were present or created at impact, but it sure sounds like the
other stuff seeped in while the meteorites lay there for how long? I mean
c'mon the exact same compounds? What are the chances of that? They've got to
stop crying wolf all the time, it's getting old.
Phil Whitmer
Joshua Tree Earth& Space Museum
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