Re: [asa] Two questions -- CORRECTION to previous post

Mike:

I don't know whether it's safe to assume that Darwin and the proponents of the modern synthesis had exactly the same arguments in mind. Of course, they may have, but I don't know how one can be sure without comparing their writings. In any case, I have not read the writings of the founders of the modern synthesis, so I was purporting to answer only your first question.

I took your first question to be, not a speculative one, i.e., "What were Darwin's probable reasons for insisting upon gradualism, given his general principles?", but a historical one, i.e., "What were Darwin's stated reasons for insisting upon gradualism?" Therefore, I provided such quotations as I was able to find on short notice. I do not claim that they provide an exhaustive list of Darwin's reasons, and he may well elsewhere have stated the reason that you have inferred. And even if he didn't, I'm not objecting to your inference. But I'm surprised that you don't seem much interested in what he actually wrote.

In any case, while I am here, I wish to issue a correction to my previous reply to you. In my post, I wrote:

"3. Darwin noted the interaction of complex parts and systems in an organism, and reasoned that for a great leap to occur, a completely new organization would have to pop up, and that this would be wildly unlikely. (Chs. II, VII)

"Regarding reason 3, note that Darwin was anticipating the "tornado assembling a 747 in a junkyard" objection to evolution, and saying that he agreed with the objection: evolution couldn't possibly work in that way. (Note also that reason 3 employs essentially Paleyesque-ID type reasoning, including the analogy to machines, so that if the core arguments of Paley and ID are to be banned from the schools as "religious", one of Darwin's own arguments against gradualism must also be banned from the schools as "religious".)"

In the last sentence, I should have written "one of Darwin's own arguments FOR gradualism" or "one of Darwin's own arguments AGAINST saltationism".

Cameron.

  ----- Original Message -----
  From: Nucacids
  To: Cameron Wybrow ; asa@calvin.edu
  Sent: Wednesday, April 15, 2009 10:30 PM
  Subject: Re: [asa] Two questions

  Hi all,

  Thanks for the answers. I should make it clear I claim no expertise here nor do I claim to have *the* answer(s). But why let that stop me from spouting off?

  In my opinion, the two questions are related. Koonin identifies two principal concepts of the Modern Synthesis as follows:

  - Fixation of (rare) beneficial changes by natural selection is the main driving force of evolution that, generally, produces increasingly complex adaptive features of organisms.

  - The variations fixed by natural selection are 'infinitesimally small'. Evolution adheres to gradualism.

  Thus, I don't think observations about blending theory or Lamarkianism apply. Those might partly explain Darwin's thinking, but they fail to explain the Modern Synthesis - its commitment to gradualism and its original rejection of Neutral Theory.

  My guess is that Darwin, like so many other great scientists, was greatly influenced by Newton's success in finding a small number of simple laws that explained just about everything. In other words, Darwin and the architects of the Modern Synthesis, sought a simple, elegant explanation for all of evolution. And in this Explanation, natural selection was supposed to be ubiquitous because then natural selection would exist almost as a Law.

  So Darwin would insist on strict gradualism because it meant that Natural Selection was effectively omnipresent, always scrutinizing every bit of variation that popped into existence. And we can change Koonin's observation, "the Modern Synthesis, in its 'hardened' form, effectively, rejected drift as an important evolutionary force, and adhered to a purely adaptationist model of evolution" to ""the Modern Synthesis, in its 'hardened' form, effectively, rejected drift as an important evolutionary force *because it* adhered to a purely adaptationist model of evolution." The "purely adaptationist model of evolution" comes from viewing natural selection as omnipresent and the existence of drift as an important evolutionary force denies such omnipresence.

  The advantage to my explanation is that it answers both "why?" questions with great parsimony.

  - Mike

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Received on Thu Apr 16 09:52:05 2009