Stephen wrote:
SJ> But TE has to be absolutely deterministic if it maintains
> that if the tape was re-run then purely natural forces would produce
> the same result.
I disagree. This is an important point. Both PC and TE allow for God's
"guidance" of evolution in ways which are not "absolutely deterministic."
I wrote my formation-of-a-new-species example, below, to make this point.
I believe, as you do, that God can guide events in ways which are
undetectable scientificially (in principle or in practice), but which are
also not "absolutely deterministic." In fact, I believe that God does
this fairly often, especially in events which affect us significantly
(e.g. spiritually important events).
I think the hang-up here is your use of the term "purely natural forces."
That smacks of deism. TE does not say that biological history happened by
"purely natural foces." Rather, TE says that natural mechanisms provide
(or eventually will provide) an adequate scientific account for biolgoical
history. There is an important (if sometimes subtle) difference! The TE
view -- like the PC view -- allows for God's guidance of (and even subtle
intervention in) natural mechanisms.
The difference as I see it: PC argues that the cumulative affect of this
"guidance" will show itself to be supernatural intervention (because of
the staggering improbabilities involved) in certain events (e.g.
abiogenesis, increasing complexity, origin of higher taxa). TE argues
that the possibility (perhaps even probability) of those events is
inherent in the natural mechanisms.
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SJ> Consider Acanthostega. Science believes that it
> grew a leg from a fin through millions of years before it needed it
> and by a "lucky coincidence" the leg was useful for another purpose -
> walking on land (Zimmer C., "Coming Onto the Land", Discover, June
> 1995, p127).
Minor point: we do not yet know enough about genetics to determine the
relative (un)likelihood of the eventual development of a "leggy fish."
SJ> Without that "lucky coincidence" we humans would not be here.
> Consider the random events (asteroid collisions?) that are
> thought to have caused the mammal-like reptiles to evolve into mammals
> (Kemp T., "The Reptiles that Became Mammals", New Scientist, vol. 92,
> 4 March 1982, p583).
>
> If TE maintains that these seemingly random events were programed
> into the natural laws of the Universe from day 1 to achieve exactly
> the end they did achieve, then they must believe in an extreme
> determinism.
Again, I disagree. (Some TE's are what you would call "extremely
deterministic." Many are not.)
SJ> PC would not reject this as impossible, but would
> rather interpret these so-called random events (if they in fact
> occurred) as the result of special interventions of God.
>
> LH>Here is a parallel question to the biological evolution one: Would
> >our solar system and planet turn out the same way if the tape of
> >stellar evolution were re-run? (Would the moon be the same size, the
> >continents be in the same place, etc?)
>
> I believe that God directly intervened to shape the Earth-moon
> sub-system. Hugh Ross, on his Reasons To Believe home page
> (http://www.dnai.com/~westley/), claims that the moon was the result
> of an asteroid collision which also blew of the Earth's original
> poisonous atmosphere. This would have required precise control to
> achieve that result. Both the moon and the removal of the
> early atmosphere were essential to life later developing.
Let us suppose that such an unlikely event is _necessary_ for a planet to
house primitive life. Since there are 10^11 stars in our galaxy alone, we
are still unable to know, scientifically, whether or not God nudged a few
asteroids together in just the right time and place in this PARTICULAR
solar system, or whether it would have happened without nudging.
When we discuss these "unlikely events" (such as asteroid collisions and
seemingly nonadaptive biological features which later allowed species to
invade new adaptive zones) we are in danger of muddling two concepts which
we must distinguish.
We should separate these two questions:
(1) What is the likelihood that the natural mechanisms (mutations, natural
events including natural disasters, and natural selection) could account
for the general features of biological history: eventual appearance of
first life, increasing complexity, appearance of new lifeforms and higher
taxa in relatively short periods of time followed by long periods of
stasis, etc?
(2) What is the likelihood that unguided natural mechanisms would produce
the PARTICULAR path of biological history on earth, including the
appearance of mammals and humans?
Arguments about dinosaur-killing asteroids address the second question,
not the first. However, the difference between PC and TE is over the
first question, not the second.
The second question is scientifically addressable, but the answer is not
very _interesting_ scientifically except as a curiousity. (The second
question does, however, relate to important _theological_ issues about
God's governance of creation.) The first question is scientifically
addressable, and the answer is VERY interesting scientifically. Phillip
Johnson, and you, and all the other PC authors I have read, argue that the
answer to the first question is, "very unlikely." That seems to be the
crux of the PC argument! THAT is where TE's disagree with PC.
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> LH>If God proscriptively determines the outcome of "chance" events,
> >then God could guide evolution along a specific pathway: for
> >example, the appearance of a new species within an isolated
> >subpopulation of an old species. No _single_ "chance event" (a
> >mutation, or an environmental event, or whatever) would have been
> >identifiable as a supernatural event.
>
> I don't claim that man could ever identify God's interventions. They
> could be much more subtle than that.
But unless I am mistaken, you _do_ argue that the _cumulative_effect_ of
these interventions would be identifiable as supernatural / intelligently
guided -- or at least, be so improbable as to defy credible explanation in
terms of natural mechanisms.
SJ> If we were watching Acanthostega
> we would not see the genetic engineering that would cause its
> offspring to produce a strange fin that would become over time (and
> subsequent generations), the first leg. God only needs to make the
> minimum change to achieve His end. He does not need to produce a
> hopeful monster such as Goldschmidt's naturalism needed.
Agreed.
> LH>If the _cumulative_ effect of these events demonstrate obvious
> >"guidance" (e.g. in just a few generations a novel, complex
> >morphological feature developed requiring many mutational steps but
> >without any selective advantage for each step along the way), this
> >would fit the "Progressive Creation" model.
SJ> Agreed. Even some "selective advantage" would be OK. Natural causes
> are OK within PC, as long as the decisive factor (the vertical
> increment) was due to God's direct intervention.
> LH> On the other hand, if the cumulative effect of all of these
> >"chance events" does NOT demonstrate obvious "guidance" (e.g. one
> >mutation in a developmental program gene caused a significant (though
> >not very deleterious) morphological change which was then acted upon
> >by "ordinary" microevolutionary processes to stabilize a new and
> >significantly altered form) -- even though God proscriptive
> >determined each little event along the way -- this would fit the
> >"Theistic Evolution" model.
SJ> But I understand that these "developmental program genes" are
> extremely complex, and the probability of an undirected random
> mutation causing any significant improvement is zero. And one would
> not be enough. You need a series of them, perhaps thousands, in
> precisely the right order. What would have been the good if
> Acanthostega got the first mutation and another species altogether got
> the second? Or if Acanthostega got the mutations in the wrong order?
Ah, this is where our scientific understandings/intuitions differ. The
best neo-Darwinian hypothesis, as I understand it, goes something like
this: the mutation in the developmental gene (or alternatively, the new
collection of pre-existing alleles) need not cause a "significant
improvement," only a significantly altered morphology (that's not terribly
uncommon) which opens up a heretofore unexploited adaptive zone (e.g. new
food source, hiding place from predators, etc.). (It's the availability
of unexploited adaptive zones which is presumably the rare occurrence.)
(Micro)evolutionary processes can then work normally to increase fitness
in the new zone. Perhaps this hypothesis still sounds far-fetched to you,
but based on what I've learned so far, it seems a reasonable working
hypoethesis to me.
SJ> " Further studies are needed to convince scientists that Duboule and
> his colleagues have correctly solved the fins to-feet riddle. Other
> factors could be involved as well, including homeobox genes that are
> not Hox genes (that is, they do not affect the overall structure of an
> animal)....The drawback for scientists is that nature's shrewd economy
> conceals enormous complexity. Researchers are finding evidence that
> the Hox genes and the non-Hox homeobox genes are not independent
> agents but members of vast genetic networks that connect hundreds,
> perhaps thousands, of other genes. Change one component, and myriad
> others will change as well-and not necessarily for the better. Thus
> dreams of tinkering with nature's toolbox to bring to life what
> scientists call a "hopeful monster"-such as a fish with feet-are
> likely to remain elusive. Scientists, as Duboule observes, are still
> far from reproducing in a laboratory the biochemical are that nature
> has taken millions of years to accomplish." (J. Madeleine Nash,
> Chicago, "Where Do Toes Come From?", TIME, August 7,1995, p69)
The complexity argument cuts both ways, does it not? One gene can affect
many features; also, most features are affected by many genes. (As I read
biological literature, I'm surprised how often transgenic animals can
function fairly well with a supposedly terribly important gene mutated or
missing.) This complexity of function allows for the formation of many
alleles within a species. The existence of many alleles, in turn,
increases the possibility of "evolutionarily interesting" combinations.
Again, have a difference of scientific intuition. You see the evidence
pointing towards strong mechanisms for stabilizing species. I see the
evidence pointing towards strong mechanisms for stabilizing species MOST
of the time, but with the possibility on rare occasions for fairly rapid
morphological changes in certain populations.
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> LH>Comment 3: Stephen, please correct me if I am wrong, but it is my
> >impression that one of the major (theological) reasons for your choosing
> >PC over TE is that you see a strong dichotomy between "natural" events and
> >"divinely intervened" events. (I also suspect you share this view with
> >other noteable PC's like Phillip Johnson.)
> The real reason is that the Bible reveals the Lord as a God who
> intervenes in history and changes it, according to His eternal
> purpose.
Agreed. The Bible also reveals the Lord as a God who clothes the grass of
the fields and feeds the birds of the air.
>
SJ> I do make a distinction between creation and providence, based on
> Gn 2:1-3 where creation is said to have been "completed" (Gn 2:1)
> and "finished" (Gn 2:2).
Your argument seems to go like this: (1) Creation is "completed." (2)
Natural evolutionary mechanisms (mutation, natural selection, etc.) are
still on-going. (3) If natural mechanisms were responsible for the
formative history of the biological world, creation could not be
considered
"finished."
But note: The natural mechanisms believed to be responsible for the
formation of the earth's atmosphere and ocean (release of trapped gasses
via heating due to meteor bombardment and geothermal activity) are still
happening today, too!
That is why I have argued that "completed" probably refers to the
conception/planning phase and the acquisition-of-materials phase of
creation than to the mechanisms-used-in-formation phase.
----
Thanks for the ongoing discussion,
Loren Haarsma