Re: Kelvin and Darwin

Moorad Alexanian (alexanian@uncwil.edu)
Fri, 12 Nov 1999 16:40:27 -0500

Is there a minimum time required for evolution to occur? How is this minimum
calculated?

Moorad

-----Original Message-----
From: Ted Davis <TDavis@messiah.edu>
To: Asa@calvin.edu <Asa@calvin.edu>
Date: Friday, November 12, 1999 4:23 PM
Subject: Kelvin and Darwin

>Allan Harvey writes:
>
><"Darwin was shocked, because Thomson's figure for the age of the earth
>eliminated the possibility that his theory of evolution could be correct.
>
>There simply would not have been time for the geological processes on which
>Darwin's theory was based to have occurred. If Thomson was right, the
earth
>must have been created with a ready-made geology. Archbishop Ussher's date
>of 4004 BC could be right."
>
>MY COMMENT: The Ussher part is ridiculous, and likewise the part about "a
>ready-made geology," which is worthy of AD White for its tone. On the
other
>hand, Darwin was seriously concerned about this. See below.
>
><He then tells of Darwin's son George verifying Thomson's calculations, and
>
>then tells how those calculations were underestimates because of incorrect
>
>assumptions about how the Sun worked and because he was not aware that heat
>was generated in the Earth via radioactivity. The overall picture he
paints
>is one in which Kelvin had scored what even Darwin perceived as a near
>knockout blow against evolution, and that the theory was only saved by the
>discovery of radioactivity.
>
>Harvey wants to know:
><Is this characterization anywhere near the truth? Kelvin's age
>calculations
>gave about 100 Myr, a factor of 45 less than the current best number. But
>
>was enough known about the "speed" of evolution in the late 19th century to
>say that 100 Myr would not have been enough time for Darwin's postulated
>evolution to have happened? Certainly the more time the better for Darwin,
>and if Kelvin had come up with 100,000 years that would have been a huge
>blow to Darwinism. But was 100 Myr really low enough to discourage Darwin
>and temporarily turn scientific opinion against evolution?
>
>ANSWER: Darwin certainly did envision an earth much older than 100MY, the
>upper end of Kelvin's calcuations. But (yes) there was no way to get ages
>that we would today call reliable, and the absence of knowledge of
>radioactivity is a major factor here. Most of Darwin's contemporaries,
even
>his friends like Huxley, tried to find ways to make evolution go much
faster
>than Darwin thought it did. They appealed to mutationism,
neo-Lamarkianism,
>or both; even Darwin himself modified his own theory significantly in later
>editions of the Origin. This whole episode is part of what Peter Bowlers
>calls "The Eclipse of Darwinism" in his book of that name. I also
recommend
>"Lord Kelvin and the Age of the Earth," by Joe Burchfield.
>
>OVERALL: Youngson uses mainly facts to draw an absurd conclusion.
>
>Ted Davis
>