Mutation

John Wilkins john at publications.ccc.monash.edu.au
Fri Jul 10 01:32:46 EST 1992


In article <9207100053.AA01146 at genbank.bio.net> , LEARN at UCRVMS.BITNET
writes:
>I was taught that the chance (= random?) nature of mutations is in
relationship
>to the needs of the organism.  This is classical Neodarwinian dogma, but
serves
>as a good null hypothesis (to a fair approximation).

As a non-biologist (philosophy student), I would say that the randomness
is
with respect to the evolutionary process generally. Certainly, the
Lamarckist
directionalism of needs related change is one target of the Darwinian
dogma,
but so is the Spencerian/Lamarckian providentialism that evolution is
tending to diversity and complexity  (whatever the debate may be in 
macroevolutionary terms, there is no innate reason to think that under
all 
circumstances evolution will lead to anything particularly), and
teleology generally.

We don't need to have some quantum uncertainty to have evolutionary
chance,
any more than we need it to have "free will". There are most certainly
determinate causal processes underlying genotypic change or else we'd
have no genetics. But these causal processes are not themselves relevant
to evolution, since whatever the underlying substrate may be, if the
result is heritable, evolution will be much the same. For this reason,
evolutionary models may be robustly applied to social, cultural and even
theoretical change (eg, David Hull's 1988 _Science as a process_, U
Chicago P). Evolution is "Darwinian" iff the nature of the change is not
in fact determined by the ends the process will attain.

Hence, the chance referred to in "chance mutation" has to be at its most
general,
randomness with respect to species or higher taxa change.

I know that non-biologists stick their foot in it every time they have a
go at evolution, so have at me, folks, if you disagree.

John Wilkins
Monash University, Australia
john at publications.ccc.monash.edu.au



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