[Maybe the reason why seeing purpose in nature is "remarkably resilient" is
because it is really there!]
Pim: Perhaps but there is no evidence of a purpose. The need of some to see a purpose
is faith based apparantly
This is interpreted as "an explicit molecular mechanism that assists the
process of evolutionary change" 2 (or even "a way of saving up mutations
for a rainy day" 4). Similarly, it is widely believed that organisms increase
mutation rates under stressful conditions to improve their chances of hitting
on appropriate adaptations 5.
[Saving up mutations for a rainy day? Go and wash out your mouth with
soap!]
Pim: Why?
Such interpretations seem to call for the evolution of properties that
anticipate future needs. But selection lacks foresight, and no one has
described a plausible way to provide it. In principle, group selection might
produce results that seem to escape this limitation. For example, increased
mutation rates may indeed allow populations to adapt more quickly to
changed conditions, even though they harm most individuals. The
evolutionary problem is that such group benefits are usually weaker than
individual costs, in a well-defined sense that makes group selection
effective only under very restrictive conditions 6. So, in general, we need
explanations that are based on individual fitness differences 7.
[Note the dogmatic assumption that the only possible explanation must
be natural selection.]
Pim: You are welcome to propose other explanations.
>From this perspective, the obvious function of Hsp90 is to prevent
abnormalities of the kinds that appear when it is compromised. Up to a few
per cent of adults heterozygous for a mutation that inactivates Hsp90
display significant morphological abnormality, so clearly there is selection
to maintain its function. Likewise, increased mutation under stress might
plausibly arise from trade-offs affecting individual fitness: stressed cells
may simply be unable to maintain normal DNA repair without sacrificing
other vital functions.
[Interesting that even Darwinian ideologues have to use `purposeful'
language. Trying to disguise it by using `function' instead of `purpose'
does not change its teleology.]
Pim: It's just that some will interpret the word purpose incorrectly when function is a far better
and less "loaded" description.
In the natural world, only living things (and their artefacts) have 'purposes',
and natural selection is the ultimate source of all such 'purposeful' design 8.
When speaking of the function or purpose of some feature of an organism,
we are therefore referring to the selective advantages that brought the
feature into being and that maintain it in the face of recurrent damaging
mutations. It is especially important, in any discussion of evolutionary
processes, to observe the distinction between function or purpose on the
one hand, and effect or consequence on the other. This is not a semantic
quibble. Cosmic rays affect evolution by causing mutations, but we would
not claim that they exist for that purpose. Similarly, developmental
buffering and variable mutation rates may influence the course of evolution,
but this does not mean that they evolved to that end.
[Interesting that a couple of biologists are authorities on ultimate
sources, and they know that all design is only apparently `purposeful'
design, not really purposeful design].
Pim: Interesting indeed. So what are you really trying to argue here Stephen?