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From: philjohn@garnet.berkeley.edu (Phillip Johnson)
Subject: SWAA Lecture
Date: 18 Jan 1993 16:25:42 GMT
)

     Dobzhansky's review summarized Grasse's central thesis
succinctly:

       The book of Pierre P. Grasse is a frontal attack on
     all kinds of "Darwinism."  Its purpose is "to destroy
     the myth of evolution as a simple, understood, and
     explained phenomenon," and to show that evolution is a     
     mystery about which little is, and perhaps can be,
     known.

     Grasse was an evolutionist, but his dissent from Darwinism
could hardly have been more radical if he had been a creationist. 
It is not merely that he built a detailed empirical case against
the neo-Darwinian picture of evolution.  At the philosophical
level, he challenged the crucial doctrine of uniformitarianism,
which holds that processes detectable by our present-day science
were also responsible for the great transformations that occurred
in the remote past.  According to Grasse, evolving species
acquire a new store of genetic information through "a phenomenon
whose equivalent cannot be seen in the creatures living at the
present time (either because it is not there or because we are
unable to see it)."  Grasse acknowledged that such speculation
"arouses the suspicions of many biologists... [because] it
conjures up visions of the ghost of vitalism or of some mystical
power which guides the destiny of living things...."  He defended
himself from these charges by arguing that the evidence of
genetics, zoology, and paleontology refutes the Darwinian theory
that random mutation and natural selection were important sources
of evolutionary innovation.  Given the state of the empirical
evidence, to acknowledge the existence of some as yet
undiscovered orienting force that guided evolution was merely to
face the facts.  Grasse even turned the charges of mysticism
against his opponents, commenting sarcastically that nothing
could be more mystical than the Darwinian view that "nature acts
blindly, unintelligently, but by an infinitely benevolent good
fortune builds mechanisms so intricate that we have not even
finished with analysis of their structure and have not the
slightest insight of the physical principles and functioning of
some of them."
     Dobzhansky disagreed with Grasse fundamentally, but he
acknowledged at the outset that his French counterpart knew as
much about the scientific evidence regarding animal evolution as
anyone in the world.  As he put it,

     Now one can disagree with Grasse but not ignore him. 
     He is the most distinguished of French zoologists, the     
     editor of the 28 volumes of Traite de Zoologie, author     
     of numerous original investigations, and ex-president
     of the Academie des Sciences.  His knowledge of the
     living world is encyclopedic. 

In short, Grasse had not gone wrong due to ignorance.  Then where
had he gone wrong?  According to Dobzhansky, the problem was that
the most distinguished of French zoologists did not understand
the rules of scientific reasoning.  As Dobzhansky summed up the
situation:

        The mutation-selection theory attempts, more or less     
     successfully, to make the causes of evolution acces-
     sible to reason.  The postulate that the evolution is
     "oriented" by some unknown force explains nothing. 
     This is not to say that the synthetic...theory has
     explained everything.  Far from this, this theory opens     
     to view a great field which needs investigation. 
     Nothing is easier than to point out that this or that
     problem is unsolved and puzzling.  But to reject what
     is known, and to appeal to some wonderful future dis-
     covery which may explain it all, is contrary to sound
     scientific method.  The sentence with which Grasse ends     
     his book is disturbing: "It is possible that in this
     domain biology, impotent, yields the floor to
     metaphysics."

     I began with the Dobzhansky/Grasse exchange to make the
point that whether one believes or disbelieves in Darwinism does
not necessarily depend upon how much one knows about the facts of
biology.  Belief that the various types of plants and animals
were created by an extension of the kind of changes Dobzhansky's
experiments brought about in fruitflies is at bottom a question
of metaphysics.  By metaphysics, I mean nothing more pretentious
than the assumptions we all make about just which possibilities
are worth considering seriously.  
     For example, Pierre Grasse was willing to consider, and
eventually to endorse, the possibility that the so-called
"evolution in action" which the neo-Darwinists were observing is
merely a variation within the limits of the existing genotype and
not a source of genuine evolutionary innovation.  To put the
point in the language used by some contemporary biologists,
Grasse proposed to "decouple macroevolution from microevolution." 
Such proposals havegenerally foundered on the inability to
establish sufficiently credible distinctive macroevolutionary
mechanisms. (For example, the widely publicized "new theory" of
punctuated equilibrium turned out to be just a gloss upon Ernst
Mayr's thoroughly Darwinian theory of peripatric speciation.) 
Grasse differed from the Darwinists in that he was willing to
consider the possibility that science does not know, and may
never know, how new quantities of genetic information have come
into the world.
      From Dobzhansky's viewpoint, to consider such a possibility
would be to give up on science.  As Dobzhansky saw it, we already
know a lot about how plants and animal populations vary in the
everyday world of ecological time.  Dog breeders have given us
St. Bernards and dachshunds, laboratory experiments have produced
monstrous fruitflies, mainland species have differentiated after
migrating to offshore islands, and the ratio of dark to light
peppered moths in a population changed when the background trees
were dark due to industrial air pollution.  To be sure, none of
these examples demonstrated the kind of innovation that Grasse
had in mind.  In the absence of a better theory, however,
Darwinists consider it reasonable to assume that these observable
variations illustrate the working in ecological time of a grand
process that over geological ages created fruitflies and peppered
moths and scientific observers in the first place.  By making
that extrapolation Darwinists create a scientific paradigm which
can be fleshed out with further research, and improved.  For a
critic to suggest the possible existence of some factor outside
the paradigm is helpful only if he can also propose a research
strategy for investigating it.  To Dobzhansky, therefore,
Grasse's insistence that the sources of new genetic information
might be a mystery to our science was pointless and harmful to
the cause of science.

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