Thanks for your response to my earlier post. Your input is welcome. In a
message dated 9/11/98 you wrote:
<<Natural selection is definitely considered to be one of the drivers
behind change in evolution. However, it is likely that it is not the
only one and may not be the major one in many events leading to
speciation. For example, King and Jukes early on suggested that neutral
drift (another factor in evolutionary change in the gnome) could be
considered "non-Darwinian". Self-regulated chromosomal rearrangements
and others such as Shapiro mentions might also be considered non-
Darwinian mechanisms. Some of these details are discussed further
in the PNAS perspectives paper I referenced earlier. They would
however, be considered possible evolutionary mechanisms.
>>
My problem with the various concepts of evolution that you mentioned--neutral
drift, syntheticism, change in gene content and frequency within populations,
self-regulated chromosomal rearrangements--is that they seem to have no
relationship to each other or to Neo-Darwinism. Are they alternatives to ND,
as I suspect they are? Are they subsets of ND? Are they back-up concepts, or
fall-back positions, to be used when ND fails as an explanatory concept?
Let me propose this: They are all ad hoc concepts that evolutionary
biologists call on when natural selection, i. e., Neo-Darwinism, is unable to
account for change or development. I would appreciate your response, if you
will, to that proposition.
My oversimplified understanding of the history of science is that in order to
explain a new, complex phenomena, a plethora of theories are first proposed.
After repeated observation and discussions, (sometimes rancorous) the one best
theory is winnowed out from all the alternatives. That becomes the standard
theory.
This is in essence what Darwin and later the synthecists did. They ruled out
all competing theories and declared natural selection the standard theory.
Simpson is very clear on this. Now, however, we have again a plethora of
theories, not competing with natural selection, but in some unpsecified way,
perhaps related to it, or supplanting it. But there is no theoretical
framework in which these various concepts fit, except for the vague umbrella
concept of evolution. I find this unsatisfactory theoretically, although some
evolutionist depict this as a gain over the older concept of natural
selection? Is it?
Moreover, I find little, if any relating of the concepts of evolution to
observed data in concrete ways. Take Shapiro's four categories of molecular
discoveries--genome organization, cellular repair capabilities, mobile genetic
elements, and cellular information processing. Can anyone account for them
with current definitions of evolution?
Thanks for any enlightenment you can give me on these matters.
Bob