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Today is Friday, March 29, 2024 at 07:28 AM.



uring my first year of teaching at Reed in 1983, Ronald Reagan as the president of the United States remarked that evolution was only a theory. His statement gave me plenty to work with in Biology 101. What is scientific theory? What is the relation of scientific theory to the theories of evolution? These are solid questions for undergraduates to consider. Despite volumes written on these questions by many philosophers of science, scientists have kept their attention on doing science and away from talking and teaching about the nature of science. The effect of this neglect has trickled all the way down to teachers of science in elementary schools. As a result, few students of science at any level learn about what scientists actually do. Textbooks at all levels tend to relate what scientists have done, by providing lists of detailed facts as opposed to a description of the process of science. These facts (and more unfortunately, theories) are then supposed to be memorized as immutable truths, thereby turning them into things to be believed in as opposed to consequences of the scientific enterprise. The door was left open for even the president of the United States to at best feign ignorance as to the meaning of scientific theory. So, what needs to be taught about the nature of science to keep an extremely small but vocal minority from gaining the support of so many?

Making order out of a complex world is the business of scholars. Many theologians, artists, and scientists are working to achieve this goal. People who learn from scholars, but are not necessarily scholars themselves, tend to trust them. In working to further their specific fields, scholars tend to forget to emphasize the common ground of scholarly effort. As a result, tension naturally builds, and perhaps too frequently a serious schism develops among the disciplines. This permeates our entire educational system and leads to a distrust among the disciplines.

The tension is not helped by the fact that many of the words a scientist uses are also used in the vernacular. Without proper education, the words of scientists stay in the vernacular, and of course, the intended meaning is lost. One such word is "theory." In the vernacular it means a guess about the way something works. Theory in science means something quite different. A scientific theory is a body of knowledge that relates seemingly unrelated facts like the orbiting of planets with the falling of apples and the nearly identical molecular make-up of chimpanzees and humans with the existence of over 500 species of fruit flies on the Hawaiian Islands. Adherents to the view that a little common sense is all you need to get by missed having a good science teacher in the third or fourth grade. The beauty of scientific theory is that it can deal precisely with those facts that cannot be related by common sense.

But more is needed of a theory to make it scientific. It has to have properties that allow abstractions (called models) of the natural world to be deduced from it. These models then must allow for the generation of questions (called hypotheses), which lead to experimentation or observation that in turn can allow for a refutation of hypotheses, models, and ultimately the theory itself. A great question in science is one that leads to an answer that not only refutes a model but also demolishes a well-established theory. The point is that a scientific theory must in principle be falsifiable. A repeatable observation or result from an experiment that can rock the foundations of a scientific theory must always in principle be just around the corner. If Bigfoot is actually captured, or a human skeleton is found to occur naturally in the fossilized jaws of Tyrannosaurus, major parts of evolutionary theory would have to be re-evaluated. On the other hand creationist "theory" also explains unrelated facts. But since it presumes to explain all facts, there is no fact that could possibly discredit it. It is simply not science. To claim that evolution is merely a theory is to immediately show that one is using the term in the vernacular and that scientific literacy is not present or a deliberate deception is involved. To require that the evidence against evolution be presented is oxymoronic.

There are competing theories of evolution: to name a few, Darwin's theory of natural selection, Kimura's neutral theory of molecular evolution, and Eldredge and Gould's theory of punctuated equilibrium. The refining, testing, debating, disproving, and always doubting the ubiquitousness of these theories is the business of science. But to doubt universally agreed-upon facts, such as the age of the earth