In article <9207100053.AA01146 at genbank.bio.net> , LEARN at UCRVMS.BITNET
>I was taught that the chance (= random?) nature of mutations is in
>to the needs of the organism. This is classical Neodarwinian dogma, but
>as a good null hypothesis (to a fair approximation).
As a non-biologist (philosophy student), I would say that the randomness
with respect to the evolutionary process generally. Certainly, the
directionalism of needs related change is one target of the Darwinian
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
circumstances evolution will lead to anything particularly), and
We don't need to have some quantum uncertainty to have evolutionary
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
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.
Monash University, Australia
john at publications.ccc.monash.edu.au