> The idea I've been trying to pound home is that any relevant
> definition of Evolution (relevant to the Creation vs. Evolution
> debate, relevant to the public's understanding of Evolution,
> and even relevant to the impression Evolutionists wish to convey
> to the general public) necessarily includes the concept of
> increased complexity through natural means.
I think that's a fair point.
As Brian Harper and others pointed out, there are evolutionary mechanisms
for increasing the number of nucleotides in gene sequences, mechanisms for
increasing the number of genes in a genome, mechanisms for increasing the
number of alleles in a species, and mechanisms for producing speciation.
Those would all seem to be mechanisms for "increasing complexity" over time.
A more difficult question is shether or not those mechanisms are sufficient
to produce the *observed* complexity that we see.
Others have pointed out that evolution doesn't *only* mean increasing
complexity, so I won't go further on that.
Regarding the "burden of proof," Andrew also wrote:
> The burden is on you, not me. You say
> Evolution happened/happens. I say it doesn't.
Who has the "burden of proof" is, if you will pardon me, a complex
issue. It is often tossed around in these debates (or more often, it is
used as if it were some kind of trump card), so I hope I can
offer some useful ramblings here.
At some point in the life of a scientific hypothesis, the burden of
proof is on those proposing the hypothesis. (The burden of proof was on
those proposing that cold fusion happened.) At the other extreme as
scientific hypotheses so well-established that the burden of proof is
on anyone proposing an alternative. (Conservation of energy is so well-
established that a heavy burden of proof is on anyone proposing an
energy-producing perpetual motion machine which would violate it.)
An hypothesis with (1) no proposed mechanism and (2) no corroborating
evidence has a heavy burden of proof. An hypothesis with corroborating
evidence AND one or more proposed mechanisms is usually given the benefit
of the doubt --- even if the exact details haven't been worked out, so
long as the best available calculations suggest that the proposed mechanisms
are at least plausible.
Where does "evolution" stand on that burden-of-proof spectrum? Again,
it depends what you mean by "evolution." Let's start with just common
ancestry. Corroborating evidence? The pattern of nested
homologies in gene sequences, genome organization, developmental
programs, and fossil records provides a lot of corroborating evidence
for creation happening via common ancestry and descent through
modification. Mechanisms? The various mechanisms of microevolution can
be extrapolated, and the rates of genetic changes in microevolution are
much larger than the rates necessary for macroevolution. This
suggests, to me at least, that the burden of proof is mostly on those
who argue against common ancestry.
However, I think that Andrew is questioning the more specific
hypothesis: the question of evolution producing increased complexity.
Even if you accept common ancestry, it is compatible with both
evolutionary creation (which expects that evolutionary mechanisms can
lead to increased complexity) and with versions of progressive creation
(which include common ancestry but assert that complexity and novelty
are products of intervention). Which of these two hypotheses has the
"burden of proof" on the question of complexity? That seems harder to
answer. There are natural mechanisms for increasing complexity, but
it's impossible (at present) to do a meaningful empirical calculation,
because complexity (or "organization," or "information," if you prefer
those terms) is not empirically well-defined for biological systems.
There's corroborating evidence for the evolution of increased complexity
in some "simple" biological systems (e.g. heteromeric ion channels evolving
from homomeric ion channels via gene duplication and mutation), but that
doesn't say much about the much more complex mechanisms and pathways in
cells. As corroborating evidence, it's somewhat weak.
So? So at this point, I think it's counter-productive to argue who has
the burden of proof here. On the complexity issue, both sides have a
burden to bear, and what we really need is a lot more data on comparative
genome sequences.
Enough rambling on that.
Loren Haarsma