Science in Christian Perspective

Science in Christian Perspective

Monica Marcinko Kuehn, CSCA Student Associate
20 Woodward Avenue, Dundas, ON L9H 4J5

From: PSCF 51 (June 1999): 138-139 Response: DeHaan

An article by Robert F. DeHaan ("Do Phyletic Lineages Evolve from the Bottom Up or Develop from the Top Down?" PSCF 50, no. 4, [1998]: 260ñ71) provoked a very strong reaction within me and some questions as to the nature of the ASA's journal. Dealing with the latter issue first, how does the PSCF compare within the spectrum of science journals and bulletins? I had hoped it would resemble a peer-reviewed scholarly journal with perhaps a little more allowance for the unique worldviews of its readers and contributors. However, this freedom should be tempered with a careful review/editorial process. Surely, a controversial article refuting the conventional view of stars (thermonuclear galactic bodies generating successively heavier chemical elements from hydrogen to iron) would not be published unless several important safeguards were followed. These precautions could include a serious review by experts in the field and perhaps a companion piece to provide a counter-point to the critique of stellar evolution. Moreover, any author venturing a major challenge to an established theory should bear in mind the rigor required to distinguish genuine critique from a sloppy misapprehension of the theory. Thus, the editorial process also needs to consider the unique expertise of the author; that is, the criticism of stellar evolution should be crafted by a physicist. These precautions are especially crucial within an interdisciplinary journal such as PSCF whose articles will be read by people with interests that range beyond their own experience and specific expertise.

Moving on to content of the article itself, I would like to make three short points. First, the notion that "top-down" evolution (when adequately understood) "challenges the scientific validity" of Darwinian evolution is contentious. The scientists cited who appear to challenge "bottom-up" evolution do not think a naturalistic explanation of evolution is threatened by their research. Surely the creationist abuse of the punctuated equilibrium position suggests caution here. We need to be careful how we use and apply concepts like "top-down" evolution, especially when they form part of a technical discussion in the academic world. Secondly, how do platypuses or lung-fishes fit in within a typological portrait of nature suggested by DeHaan's "top-down" approach?

The diversity of life on earth does not fit a "body plan" approachóthis view properly died out with the German transcendalists in biology over one hundred years ago. For instance, there are many organisms (transitional fossils) who are impossible to classify into any one order (or other contemporary high-level taxonomic category) due to the intermediate nature of morphological features. This fits in with some sort of naturalistic evolutionary process (whether the mechanism is Darwinian or not) and not with a body-plan view of life.

@BODY TEXT 3HY = Organisms exist(ed). We classify them into categories. Our conceptual categories often fail to do justice to the historical and messy process. If an early hooked bill bird progenitor (which was itself a speciesóa breeding collection of genes with some sort of stability over space and time) diverged into raptors and vultures then we have "bottom-up" evolution (a species diverging into what are now classified as the Cathartidae and Accipitridae families). But each of the two new species would then experience adaptive radiation which would indeed produce new varieties in a "top-down" manner to produce new families, sub-families, and genera. This is what Darwinian evolution predicts and retrodictively explains; these two approaches (bottom-up and top-down) are not antithetical as DeHaan maintains.

DeHaan's article calls attention to many of the questions dealing with the history of life on earth. The origin of many evolutionary novelties has yet to be adequately explained, and its true (or even likely) history might never be retold by hominids with six-pound brains. Nevertheless, the search for "internal developmental processes" need not be posited as an alternative to Darwinian mechanisms to account for the change in phyletic lineages. I wonder if a desire for a gap for God to fill lurks in some of the popularity of these types of Darwinian challenges. How does DeHaan account for the origin of these fundamental phyla found in the Cambrian explosion if he discounts Darwinian gradualism acting on species? Science proceeds by comparing alternatives to the prevailing theory, not by sniping from a safe sideline.

I urge readers who might be persuaded by this type of critique as a legitimate critique on Darwinian evolution (with philosophical and theological implications) to pursue peer-reviewed journals for further discussion and analysis.