[aclug-L] Re: Linux and Creationism...

[Tom Hull <thull@xxxxxxxxxxx>]

Burt Humburg wrote:
> 
> > Kelvin was also famous for one of the first serious scientific efforts to
> > estimate the age of the earth. Only off by a factor of 45 (maybe a bit more
> > if Jonathan's theories gain currency).
> 
> Kelvin is a great example of a triumph of evolution. (Sorry J-dog.) Back
> then, they didn't know about fusion power. Measurements of radiation that
> was striking the Earth were used to calculate the amount of energy that the
> sun was emitting. The resulting amount required a massive amount of chemical
> energy being consumed. It fit in nicely with a several-thousand year old
> earth as opposed to the several-million year old earth that Darwin needed.

IIRC, some errors here:

 1) Kelvin's estimate was 100Ma, which was too long for Bishop Usher and too
    short for Darwin. Usher added up all those begots and concluded that the
    earth was created in 4004 BC. Darwin, following his mentor Charles Lyell,
    favored an unimaginably long earth history, not least because he expected
    evolution to work very slowly.

 2) While Kelvin certainly didn't understand fusion -- I think it was Hans
    Bethe who, roughly 100 years later, confided to his date that he was
    the only person alive who did understand it -- the real problem with
    his calculation was that he didn't account for internal sources of heat,
    which are primarily due to fissionable elements (uranium, thorium, and
    daughter isotopes). Kelvin assumed that the earth started out as molten,
    then simply calculated the cooling time. I don't know whether Kelvin
    even factored solar radiation input into his model, but I doubt that
    it would have made any significant difference.

 3) Kelvin's earth age estimate was done in 1846. What you're probably
    thinking of is another estimate Kelvin did later on solar age. In
    the latter case, lack of understanding about fusion was critical.

> To put the point in slightly different fashion, evolution contradicted the
> science of the day.

I doubt that Kelvin (unlike Usher) ever really thought he had proven anything.
He had a calculation that he thought was inconsistent with the evolutionary
theory. It turns out that both Kelvin's calculation and Darwin's theory have
required some rework. In Kelvin's case, science has not established a longer
timespan (approx. 4400Ma vs. 100Ma); in Darwin's case, science now recognizes
that evolution can occur more quickly than Darwin had supposed (due to a new
understanding of genetic mechanics and confirmed by precise dating of the
paleontological record, nicely summed up by the Eldridge-Gould punctuated
equilibrium theory).

Evolution hasn't contradicted science so much as science has progressively
come to grips with evolution.

> In the fullness of time, at least this far, Darwin's theory has been
> validated time and time again: this is but one example. Thanks to this and
> other examples, don't let anyone ever tell you that evolution is a
> philosophy or a religion that has been exempted from the tests of science.
> It had its unsure days but its survival to this day is not a measure of
> pro-evolutionary bias; rather, it is a measure of the strength of the
> theory.

Note that Darwin's theory is Natural Selection, not Evolution. Evolution
is what Gould refers to as a "contingent fact" -- I would be tempted to
expand that to "millions of contingent facts".

BTW, I have an anti-Darwin book that's maybe 20 years old, that lodged two
main attacks on Darwin: 1) that nobody has ever observed speciation; and
2) that some hypothesized evolutions are broad and lacking any sort of
intermediate fossil forms (whales being the main example). Since then,
#1 has been rigorously demonstrated among Galapagos finches, and there
now exists a lovely series of intermediate whale fossils.

> We seem to be drifting far afield of Linux, so I'll just briefly mention
> that penguins probably evolved as well.

Of course, penguins offer many fine examples of convergence (how genetically
distinct groups evolve common solutions to similar niche roles). However,
Stephen Jay Gould once did an essay on the evolution of Mickey Mouse that
may have more specific relevance for Tux.

> BCH

-- 
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 *  Tom Hull * thull at kscable.com * http://www.tomhull.com/
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