"This is why (I) picked up the issue of limits to variation: the
neoDarwinians must justify this assumption if their evolutionary theory
is to be considered science,"
Glenn Morton wrote,
"Why should they have to be the only ones to prove their point? Why
are anti-evolutionists exempt from having to justify their position?
What you are asking is the impossible. Since logically it is very
difficult to prove a negative (it can't be done), it seems that it
would be more fruitful for the anti-evolutionist to prove the positive
i.e. that there is a limit to variation. No one can prove that there is
NO limit because that violates the laws of logic. But you as a
believer in limits should be able to prove the extent of variation."
In this discussion, I am uncertain what position is "the positive" and
what is "the negative" that is "very difficult to prove". As a general
statement, I agree with Glenn that proving the negative is difficult or
impossible. For instance, a charge that I sexually abused one of my
daughters when she was a child, would put be in the difficult position of
trying to prove a negative.
But consider the limitation described in physics by the "Pauli exclusion
principle", or, better yet, the "principle of parity". These are both
statements of limitation. In both cases, all one has to do to disprove
the limitation is to find a single example for which the limitation does
not apply. And, as I am sure Glenn is aware, the principle of parity WAS
successfully overthrown.
It seems to me that the real difficulty in the present discussion has to
do with the imprecision of the use of the word "limitation". How limited
are morphological changes? Until this is clearly stated, there can be no
clearly stated refutation.
Gordie