You responded to my first post with two posts on January 19--Limits to Change
and ReRealHist. I appreciate your responses.
In my post to you, I asked what you meant by evolution--*natural selection*
or simply *change*? You asked me to ask the question again. Let me try this
way. There are three meanings to the word evolution, as Keith Thomson noted.
("The Meanings of Evolution" Am Sci, 1982, 70:529-531). Thomson said
"Scientists can always do themselves a great service by being scrupulously
precise about the nature of their statements (529)."
The first meaning is *change through time*. "Change over time is the most
solidly based fact of evolution" said Thomson. [The most solidly based fact
of evolution? What about a human being that changes over time from a
fertilized egg to a mature adult, to a bed-ridden octogenarian? Thomson has
obviously overlooked the process of growth and development as the source of
change over time.] This meaning, however, probably represents the most
widespread use of the term, evolution. The second is "Organisms are related
by descent through common ancestryx.the process of descent from preexisting
forms." The third is natural selection--random genetic variation and
selection of the most adaptive and reproductively successful phenotypes.
I arrange the three meanings in the form of a target face, with natural
selection being the bull's eye; the first ring, descent with modification;
the second ring, change through time. The farther one moves out from the
bull's eye the further they are removed from objective, empirical data; and
the more flexibility one has in fitting the theory to many different
situations. I believe that the first meaning contains the guts of the theory
of evolution. It supplies the mechanism that second and third meanings need.
It is to them as Christ is to Christianity. Remove Christ and you have cut
the heart out of Christianity. Remove natural selection from evolution and
you have taken the indispensable causal mechanism from the second and third
meanings of evolution.
As I read your post on limits to change, I conclude that by evolution you
mean *change through time*. While you include mutations in your two posts, I
find nothing about *selection*, the second indispensable step in natural
selection. Do you agree? Or have I missed something?
Let's get on to some specifics. I asked whether a the first mutation toward
a leg would not be detrimental. Your answer was: "If the prey were faster
than a fin could move the predator, the mutation would have been advantageous
not detrimental." I doubt that. I'd guess the probability is pretty low
that an incipient leg could move a fish faster than fins and a tail. You
must have seen yourself how fast a fish can move, even in shallow water. The
*Eusthenopteron*, a crossopterygian fish looks as graceful, streamlined, and
fast swimming as any modern fish, yet is considered a lobe-fin fish that had
evolved in the direction of land-living amphibians. (Colbert and Morales,
*Evolution of the Invertbrates* 1991, p. 67). I don't doubt the transition
to land animals occurred. I merely challenge the evolutionary explanation
that relies on the land-based food, and the need to move faster to catch
hypothetical land-based food or other food as the incentive. I believe that
the genetic developmental programs were already present in the germ line of
crossopterygian fish and when the programs were expressed they drove the fish
to eventually become amphibians, thus actualizing their ability to catch
terrestrial and some kinds of aquatic food.
This brings me again to the question of form vs. function. Your examples
refer to an environmental incentive, such as food (function), which required
the evolution of legs (change its form) to realize. The environment
functions to drive the form in the evolutionary framework. Developmental
theory says its the other way around. Change of form came first (develop
legs) which then made new behavior, eating terrestrial food (function)
possible.
I resist efforts of evolutionary authors to co-opt development, or to make
development a secondary process to evolution. I gave a number of
characteristics that demarcate it from evolution. Here they are again.
Development is end-directed and purposive, internally driven, autonomous
from the environment, hierarchically organized, has a seamless genetic
connection with phyletic lineage, form of an organism appears before its
function or behavior. It is a naturalistic process. Principles of
development apply to large groups of animals over geologic time as well as to
individuals, in the developmental framework. Form precedes function in
development. Referring to the last statement you said "So why isn't this
evolution? That is exactly what evolutionists think happened. The
evolutionist thinks that the form came first in the legs then the use came
later." Not so, as I noted above. The point I want to make is that the
characteristics of development set it apart from evolution.
Natural selection, on the other hand, does not foresee the future, is
purposeless, unplanned, undesigned, originates in random mutations and is
guided by an opportunistic environment. These are avowed views of many
evolutionary authors, including Darwin, Simpson, Futuyma to say nothing of
Dawkins, Dennett, and others. Those characteristics make evolution a very
unsatisfactory paradigm to me.
It seems to me you have accepted the evolutionary paradigm, and added the
purposive activity of God to it, thereby avoiding the negative aspects of
natural selection in its strict Darwinian form. Concluding your diagram in
your Limits to Change post, you wrote "Is this a purposiveless view of
nature? Does this view destroy God's control? Of course, not. God designed
the phase spaces and in doing so, God was essentially laying down a nearly
undetectable railroad track which would lead from one animal to the next, not
according to an unplanned sequence of events but according to His
foreknowledge. In other words, God rigged the roulette wheel, BY DESIGN."
The question is, what is the "nearly undectable railroad track"? If it is
not an evolutionary "unplanned sequence of events" what is it? I claim that
the "nearly undectable railroad track" consists of developmental programs
operating in the germ line of the lineage unfolding over geologic time.
Development is the biological instrument of God's foreknowledge. The
characteristics of development make it an ideal causal agency for God's
purposive activities in the history of life on earth.
So much for today.
In good will,
Bob