<< And your saying to yourself so what? Harper's usually not this agreeable,
there must be a catch :).>>
Actually, it's pleasant to agree, catch or no. And we do agree on MY central
point, viz:
<<About the only thing I can agree with is that showing something
is not impossible is not the same as showing its probable.>>
That is the crux of my "imagined selective advantage" critique.
<< let me say first that from my
response to Randy one should not conclude that I'm some sort of neo-
Darwinian wacko myself. I don't find classical ultra-gradualistic
Dawkinsonian type Darwinism to be very convincing and this is
essentially what Denton is criticizing.>>
That's good, too. You go on, however, to your main criticism:
<<Denton is making a fundamental mistake in probability. He's
assuming (1) that there are many many many multitudinously
many paths that could be taken, only an exceedingly small
number of which lead to the desired result (an eye say) and
(2) that the random search involves a random selection among
all these possibilities each of which occurs *with equal probability*.>>
I don't see this latter assertion in Denton. In fact, he finds it "easy" to
believe a random search WILL hit upon routes leading to relatively trivial
adaptive advantages (e.g., finch beaks). He certainly is not saying there is
equal probability there. He is only going on to find such pathways
unconvincing vis-a-vis higher order, complex change.
Maybe you've got some passages in Denton that I've missed which state
otherwise. I'd be happy to look at them.
<<Well, I could go on and on this. But I think I have established the
point well enough. In a complicated process such as evolution, exceedingly
more complex than my simple double pendulum example, one simply
cannot assume that there are multitudinous paths with equal probability.
Actually, what Goodwin and others are trying to show is that practically all
the "possible" paths are not really possible after all and are excluded
for some fundamental reason so that evolution is driven in certain
directions (generic forms for example) by the nonlinear dynamics with
practically no role being played by natural selection.>>
I must admit that I find these tidy models, all numbers and neatness, to be
absolutely unconvincing in the real world. Excuse my plebian prejudices, but
while we both agree that mutational change is random, from there your argument
posits a virtually inevitable upward trend for change. But that ignores the
inevitability of negative mutational pull (among other things). I think ReMine
labels this "naive natural selection."
When you think Goodwin and others have made a convincing case to overcome
naive natural selection, let me know.
Jim
[Freudian sidenote: I kid you not, every time I type your name in these
messages, before I go back and proof read, I type out "Brain." What do you
suppose the message is?]