Re: Waddington's Revision Of Haldane


"John W Edser" <edser@xxxxxxxxxx> wrote in message news:dprmno$8lb$1@xxxxxxxxxxxxxxxxxxxxxx
> I have repeatedly objected to Waddington's revision of Haldane's basic
> population genetics equations being ignored within gene centric Neo
> Darwinism. Jim Menegay expressed interest in Waddington's revision
> and asked the professionals that post here for clarification.
> None has been forth coming. Therefore I have decided to post
> some of the photostate that I have. The cover *** was lost so
> I cannot give the exact reference. As I recall they were copied
> from Waddington's book "The Evolution Of An Evolutionist". Perhaps
> somebody else can supply the exact refrence. Here are what I
> consider to be the appropriate parts which I will post without comment.
>
> ------------- Beginning of Waddington's Revision of Haldane----------------
>
> THE NECESSITY TO CONSIDER MORE THAN ONE ENVIRONMENT
> The strict Neo-Darwjnist paradigm is unsatisfactory in another respect,
> namely, that it involves only one uniform environment, through which
> natural selection is exerted in a form which requires specification
> by one single coefficient for each type of biological entity. ...

[Snip the bulk of the Waddington's commentary for reasons of length.]

It is essentially a mathematical explanation of how Waddington's
ideas on 'canalization' and 'genetic assimilation' are compatible
with natural selection. These ideas are essentially that an organism
might first evolve the capability of developing differently in different
environments, and then later evolve the capability of developing the
same way regardless of the environment.

The naive ultra-Darwinist objection to this hypothetical sequence
of events is that the organism should not 'canalize' - if it already
has the ability to develop appropriately to the current environment,
why should it take the apparently backward step of becoming adapted
to only one environment. Waddington's math can be expressed far more
simply in words - the correct solution for the organism is to develop
appropriately for the environment in which it is most likely to
encounter during the most selective stage of its life, and that
environment might not be the current environment during the developmental
stage.

In the course of making this presentation, Waddington uses the phrase
'developed in X' to denote that an organism has undergone development
in environment X. (I had asked John to explain what the phrase meant.
Thx, John). He also does a case analysis of organisms which develop
in environment X or Y (with probabilities p and 1-p) and which
independently are selected in environment X or Y (with probabilities
q and 1-q). This algebra reminded John of Hardy-Weinberg, for obvious
reasons.

[Resuming quote from Waddington]
> Conclusions
> [..]
> What I wished to do was to exhibit a scheme of basic ideas which directs
> attention towards, rather than away from, the problems which are of most
> importance for evolutionary theory at the present time. By far the
> greatest advance in our knowledge of evolution which has occurred in
> recent years has been the discovery of the enourmous range and variety
> of genetic variation which is present in natural populations. It seems
> certain that one of the important determinants of this situation is the
> fact that such populations exist in heterogeneous environments, so that
> the applied selection criteria are not the same for all individuals.
> [...]
>
>
> ---------------------------- end ----------------------------------------
>
>
>
> I apologize in advance for any errors in the copying of this material. I am
> happy to go back and check anything that is incorrect. My scanner cannot
> scan mathematics so it all had to be done by hand.

Looked good to me. I appreciate all the work this entailed.

> I sincerely hope that this posting stimulates discussion in what I
> consider to be one of the most important subjects in evolutionary
> theory: the relationship between model and theory.

I can't comment on the relationship between model and theory, because
we seem to speak 'different languages' on this topic. But I will
comment briefly on the relationship between simple models and
slightly less simple models.

The problem (of acceptance) that Waddington faced was that simple
models using a fixed environment suggested that 'canalization' shouldn't
work. Well, actually, they didn't. The models, plus hand-wavy
arguments that changes in the environment shouldn't matter, suggested
that 'canalization' shouldn't work. Waddington corrected this
mistaken belief by using a new simple model.

First he further simplified the models of Haldane and Fisher to their
bare essentials. Then he added some new elements - most notably an
environment which varies on such a fine scale in space or time so
that an organism is likely to develop in one environment and be
selected in another. Turn the crank on this (still simple or simplified)
model and out comes the conclusion - canalization works. And I
think that he made his case. The book that I first read on evolution -
JMS's "The Theory of Evolution" - discussed canalization as one of
the phenomena which can result from NS. Waddington's ideas may have
been resisted by the establishment back when they first came out, but
many of them have been 'co-opted' into the Synthesis since then.

So I see this as a victory for simplified or oversimplified models.
The only thing wrong with the hand-wavy Darwinist arguments against
canalization was that they did not consider the case of fine-grained
variation in the environment. Waddington's model made it clear that
this is what he was talking about. Communication in words is ambiguous
and leads to continued misunderstandings. Communication in formulas
can insert the clarity needed to dissolve the misunderstanding.

I will also make a brief comment touching on 'the sociology of science'.
One of the difficulties that Waddington faced was due to his marketing
of his ideas as a challenge to the orthodoxy. The response is usually
hostile when someone says, "Natural Selection can't explain evolutionary
phenomenon <X>. I can explain <X> using my new principle. My principle
should be ranked along with NS as a second cause of evolution."

The hostility predictably passes through three stages.
1. Phenomenon <X> doesn't exist.
2. The phenomenon does exist, but your principle can't be the
explanation because it is incompatible with NS.
3. NS already incorporates this principle in its explanation
of the phenomenon. You have contributed nothing new.

This sequence has played out over and over. Besides Waddington's
canalization, Baldwin's 'effect', and Gould and Eldridge's punk
eek, it also has played out to some extent regarding kin selection.
You, John, seem to be stuck in stage 2. But Hamilton avoided the worst
of the hostility because he never marketed his ideas as a challenge
to the orthodoxy. Instead, he started with something close to
stage 3. He said, in effect, "Here is an interesting principle
already incorporated in NS, but heretofore unnoticed." That approach
seemed to work better, at least for some audiences.


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