Further Reflections on Darwin on Trial


Astronomy and History of Science
Harvard-Smithsonian Center for Astrophysics
Cambridge, MA 02138

From: PSCF 44 (December 1992): 253-254.

For some of the ASA members attending the 1992 Annual Meeting in Kona, Hawaii, a highlight was a spontaneously organized discussion session following Phillip Johnson's paper. In the round-robin of correspondence that has ensued since the meeting, I realize that some of my own remarks at this session as well as my review of Johnson's Darwin on Trial (PSCF, June 1992) were not understood as clearly as I had hoped.

On one point there was unanimous agreement: the issue is not evolution versus creation. The issue is design versus accident.

Phillip Johnson has impressively documented the extent to which much evolutionary teaching comes with philosophical baggage claiming that "accident" is a real feature of the world, "proven" by evolutionary doctrine. In the time since Newton, science has used mechanistic explanations that dispense with divine intervention (the "God of the Gaps"), and with considerable success. To the extent that design represents divine intervention and "accident" does not, the later explanation can be invoked as part of a mechanistic explanation. All too frequently teachers in their naivete, or because of a deliberate atheistic orientation, present their material as if such a mechanism describes the actual world rather than being simply a rule of science.

Johnson and I both agree that the teaching must become more nuanced in its presentation, and we both reject evolutionism as a philosophy. But in my reading of Johnson, his strategy appears to invoke a frontal attack on evolution. I think this is misguided and ultimately fruitless. My brief is to launch the attack against the atheists who are using evolution to further their materialistic philosophies, against those who raise a reasonable structure of scientific explanation into a naturalistic ideology.

In an upcoming article ("Theistic Naturalism and The Blind Watchmaker," scheduled for the March 1993 issue of First Things) Johnson presents statistics to the effect that only a small minority of Americans accept the seemingly accidental, zig-zag pathways of evolution as being the wholly mechanistic way that brought intelligent life into existence. Part and parcel of Johnson's strategy is to define evolution in those terms, with the insinuation that anyone who thinks of evolution otherwise (in fact, the majority) is being duped. And, he maintains, the mechanisms that could build up the great chain of being, from microorganisms to fishes to mammals, are so flimsily and inadequately demonstrated that the whole structure should be dumped.

My counterstrategy would be to accept evolution as a reasonable theoretical structure for explaining a great many relationships in the biological world. It gives a very sensible explanation of why the DNA in yeast is so closely related to the DNA in human chromosomes, or why the genetic content of chimpanzees is so similar to those of Homo sapiens. It explains numerous morphological patterns from the coelocanth to the gorilla. It provides an insight into the many examples adduced by Darwin for imperfect adaptation. It helps us understand why Hawaii has so few species compared to the older continental areas, and why there would be flightless birds on the islands (now, alas, extinct since the recent introduction of such predators as the mongoose). Johnson's rejoinder is that distribution of species is not evolution. Of course not, and I never claimed so; but it is an excellent example of the sort of empirical evidence that remains mysterious and even capricious in the absence of some sort of explanatory structure, which the theory of evolution supplies.

The theory of evolution requires two basic elements: variation and selection. Darwin was greatly baffled as to how variation could arise, and his theory was rejected in many scientific quarters until a much greater understanding of genetics, and ultimately of the chemical basis of genetics, was achieved. There still is no satisfactory detailed mechanism for producing large enough, non-lethal variation of the DNA to produce a new species in a single jump, and it remains an act of faith on the part of evolutionists that there is some way for it to have happened bit by bit. As a Christian theist, I believe that this is part of God's design. Whether God designed the universe at the outset so that the appropriate mechanisms could arise in the course of time, or whether God gives an occasional timely input is something that science, by its very nature, will probably never be able to fathom. But as a scientist, I accept evolution as the appropriate explanatory structure to guide research into the origins and affinities of the kingdoms of living organisms.

In closing my review of Darwin on Trial, I expressed my frustration by Johnson's apparent lack of appreciation about how science works, and this seems to be the least understood statement in my review. In Kona I tried to illustrate what I meant by mentioning Foucault's pendulum experiment, carried out in Paris on the night of 7-8 January 1851. The next morning there was not dancing in the streets because finally experimental proof for the earth's rotation had been found and that Copernicus was right. It was a marvelous demonstration, but Foucault's pendulum hardly affected the status of Newtonian theory or heliocentrism. It made no difference--people were already convinced about a rotating earth because Newtonian physics connected so many observations together into a coherent structure. I firmly believe that science concerns itself mostly with building coherent patterns of explanation, and rather little with proof. Lawyers seek proofs, and that's why I said that Phil Johnson was approaching science like a lawyer, somehow supposing that if he could show that evolution has no proofs, it would crumble. That, I think, is misguided.

In the discussion in Hawaii, John Wiester spoke well of the Science paper by Alan Lightman and me, in which we analyzed anomalies in science and the resistance of scientists to acknowledging them (Science, 255, pp. 690-695). But the essential, underlying thesis of the paper was that anomalies will generally pass unrecognized until the availability of an alternate theory in which they suddenly make sense. When I said above that Johnson's approach would probably be fruitless, I did so in this precise context. Until or unless there is another acceptable scientific explanation for the temporal and geographical distribution of plants and animals and their structural relationships, biological evolution will remain the working paradigm among scientists. To invoke God's active agency as the explaination for slow, long-term changes in the biological record will be no more efficacious as a scientific theory than to say that the moon orbits the earth or apples fall from trees because of God's sustaining activity in the universe. While I believe both to be true, they do not pass as scientific explanations. In reading Darwin on Trial, I am left with the impression that Johnson wishes they would.