Despite the great value of presenting opposing viewpoints, the popular debate over origins has fostered several misconceptions about evolution, design and science itself. To get the most benefit from this supplement, teachers should understand these misconceptions and be prepared to face them in an open and fair-minded manner when they arise.

One misconception concerns the status of evolution as a fact. In the origins debate it is common to hear the assertion that evolution is not merely a theory but an indisputable fact.8 Educators who take this view argue that it is futile and misleading to present non-Darwinian views as serious alternatives to Darwinian evolution.

The factual status of evolution, however, depends critically on what the word "evolution" means. Yale biologist Keith Stewart Thomson points out that scientists have used the term in at least three different ways.9

The first meaning he identifies is "change over time." In this sense, to say that evolution has taken place is to say that change has occurred and that things are different now from what they were in the past. The fossil evidence, for example, reveals different organisms from one geological period to the next.

When the word is used in this sense, it is hard to disagree that "evolution" is a fact. The authors of this volume certainly have no dispute with that notion. Pandas clearly teaches that life has a history and that the kinds of organisms present on earth have changed over time.

The second meaning that Thomson identifies is descent with modification--the idea that all organisms are "related by common ancestry."10 Evolution in this sense is a theory about the history of life. In Darwin's view, that history can best be depicted as a single branching tree--a genealogical tree--in which life diversifies over time.

Many people assert that evolution in this second sense is a fact, just as gravity is a fact. But the two situations are hardly analogous. The fact of gravity can be verified simply by dropping a pencil--an experiment anyone can perform. Common ancestry, however, cannot be directly verified by such an experiment. We can no more "see evolution in the fossil record than paleontologists of Darwin's day could "see" creation events. The best we can do is infer what might have happened in the past by piecing together circumstantial evidence from many different fields.

Darwin, for example, sought to establish common descent by examining evidence from several different areas: paleontology, biogeography, comparative anatomy and embryology. Others have relied additionally on evidence from genetics, molecular biology and biochemistry.

The problem with this kind of historical detective work, however, is that it seldom produces a conclusion that forecloses other alternatives. As philosopher of biology Elliot Sober points out, there may be any number of plausible explanations--or "past histories"--that can account for the same evidence.11 Sober's observation recalls the insightful warning of fictional detective Sherlock Holmes. "Circumstantial evidence is a very tricky thing!" said Holmes. "It may seem to point very straight to one thing, but if you shift your point of view a little, you may find it pointing in an equally uncompromising manner to something different."12

The point is, unless we can eliminate all competing explanations,, it's presumptuous to call descent with modification a fact. As most people understand the term, a fact "is supposed to be distinguished from transient theories as something definite, permanent and independent of any subjective interpretation by the scientist."13 By this definition, descent with modification simply doesn't warrant the status of a fact. Far from compelling a single conclusion, the evidence may legitimately be interpreted in different ways, leading to several possible conclusions. None of those conclusions warrants the status of "fact." As zoologist Thomas Kemp warns:

All attempts to understand the diversity of organisms rely upon empirically untestable assumptions either about evolution or about natural patterns. There is nothing wrong with making assumptions or seeking to justify them, of course. It is the very stuff of science. What is unforgivable is to forget that they are assumptions and behave as if they were known certainties when they are no such things.14

Indeed, calling common descent a fact only closes off debate and blurs the distinction between fact and inference. That, in turn, makes us particularly vulnerable to the illusion that we know more than we really do. In the preface to his best selling volume, The Discoverers, Daniel Boorstin tells the reader:

The obstacles of discovery--the illusions of knowledge--are also part of our story. Only against the forgotten backdrop of the received common sense and myths of their time can we begin to sense the courage, the rashness, the heroic and imaginative thrusts of the great discoverers. They had to battle against the current "facts" and dogmas of the learned.15

This is precisely why a book that questions the Darwinian notion of common descent is so necessary. By presenting a reasonable alternative to evolution in the second sense (i.e., common ancestry), Pandas helps students learn to work with multiple perspectives from facts and to guard themselves again the illusion of knowledge.

The final meaning of evolution that Thomson identifies concerns the mechanism of biological change-- the particular explanation of how evolution in the first two senses occurred. Here the term "evolution" refers to random variation and natural selection. In Thomson's words:

Although many biologists act as though [the mechanism] were the whole meaning of evolution, it obviously is not. The first and second meanings could be explained by several different theories, and both had a serious intellectual history before 1859, while the third meaning is currently confined to a particular explanatory hypothesis, Darwinism.16

Evolution in this third sense asserts that the cause of mechanism of biological change is purposeless, non-intelligent and completely naturalistic.17 Oxford zoologist Richard Dawkins defended this view in his best-selling book, The Blind Watchmaker.18 Like Darwin himself, Dawkins acknowledges that biological organisms appear to exhibit remarkable design. Yet both men claim that this appearance is an illusion, produced entirely by random variation and natural selection. Blind nature mimics intelligent design.

This "blind watchmaker" thesis is often touted as a fact, but it is not. For one thing, Darwinists have never demonstrated empirically that natural processes can create the complex structure that characterize living organisms. Like common descent, the blind watchmaker thesis is based on indirect evidence. It accounts for hypothetical transformations by extrapolating small observed changes over immense periods of time. Thus, the blind watchmaker thesis is not a fact, but an inference.19

What's more, the blind watchmaker thesis--at least in its neo-Darwinian form--may not be a warranted inference. As we mentioned at the beginning of this essay, neo-Darwinism has come under growing attack from scientists and philosophers alike. Scientists have increasingly questioned the ability of mutation and natural selection to generate new organs, limbs of body plans.20 A host of other problems have led biologists Mae-Wan Ho and Peter Saunders to say:

Until only a few years ago, the 'synthetic' or 'neo-Darwinist' theory of evolution stood virtually unchallenged as the basis of our understanding of the organic world ... Today, however, the picture is entirely different. More and more workers are showing signs of dissatisfaction with the synthetic theory. Some are attacking its philosophical foundations ... Others have deliberately set out to work in just those areas in which neo-Darwinism is least comfortable, like the problem of gaps in the fossil record or the mechanisms of non-Mendelian inheritance ... Perhaps most significantly of all, there is now appearing a stream of articles and books defending the synthetic theory. It is not so long ago that hardly anyone thought this was necessary.21

Pandas gives students a much-needed opportunity to explore the evidence and arguments that have caused some scientists to doubt contemporary Darwinism. It examines evidence from such fields as biochemistry, genetics and paleontology--evidence that casts doubt on the sufficiency of purposeless processes to explain the appearance of new biological forms.

Going a step further, Pandas helps students understand the positive case for intelligent design. Following a growing number of scientists and philosophers, the authors argue that life not only appears to have been intelligently designed, but that it actually was. Drawing on recent developments in molecular biology, the authors show that even simple organisms bear all the earmarks of designed systems.

The authors will also discuss what scientists have learned by applying mathematics and information science to biology. The disciplines suggest the possibility of distinguishing natural systems from intelligently designed ones--and have led some scientists to conclude that the "coded genetic information" (or sequence specificity) of DNA, proteins and the like, reflects the activity of a pre-existent intelligence.22 While that conclusion is still controversial, a growing minority of scientists see it as a plausible alternative to the blind watchmaker thesis.23

By presenting the case for intelligent design the authors demonstrate that there are indeed alternatives to the blind watchmaker thesis--and that evolution as a purposeless process is neither an indisputable fact nor the only inference supported by biological data.

In sum, then, only in the most trivial sense--change over time--can evolution be considered a fact. Far from being a legitimate reason for avoiding alternative views, the alleged "fact of evolution" underscores precisely why a book like Pandas is so necessary. If students are to achieve true scientific literacy, they must learn to distinguish fact from supposition. A curriculum that blurs this distinction serves neither the students nor society.

Endnotes
8. See for example the 1990 California Science Framework, published by the California Department of Education. See also Ruse, M. (1982). Darwinism Defended: A Guide to the Evolution Controversy. London: Addison-Wesley, p.58.

9. Thomson, K.S. (1982). "Marginalia: The Meanings of Evolution." American Scientist, 70:529-531.

10. Ibid.

11. Sober, E. (1988), Reconstructing the Past. Cambridge, MA: MIT Press, pp. 4-5. See also Campbell, D.T., and Stanley, J.C. (1963). Experimental and Quasi-Experimental Designs for Research. New York: Houghton Mifflin.

12. Doyle, Sir A.C. The Boscome Valley Mystery. Quoted in Capretti, G.P. (1983). Pierce, Homes, Popper. In U. Eco & T. Sebok (eds.), The Sign of Three, Bloomington, p. 145.

13. Fleck, L. (1979). Genesis and Development of a Scientific Fact. Trans. by Thomas Merton. Chicago: University of Chicago Press, p. xxvii. Actually, Fleck argues that there is really no such thing as a "fact" in this sense. All "facts" involve a certain amount of subjective interpretation. If this is so, it strengthens the case against the "fact" of evolution (in the sense of common descent). Nevertheless, we still believe that the fact/inference distinction is a useful one, underscoring as it does the difference between ideas in which we have great confidence and those that seem less sure.

14. Kemp, T. (1985). Models of Diversity and Phylogenetic Reconstruction. In Oxford Surveys of Evolutionary Biology, Vol. 2 (R. Dawkins & M. Ridley, eds.), 153.

15. Boorstin, D.J. (1985). The Discoverers. New York: Vintage Books, p. xv.

16. Thomson, 1982, p. 531.

17. Thomson, 1982, pp. 530-31.

18. Dawkins, R. (1986). The Blind Watchmaker. London: Longman.

19. See for example Ridley (1985), pp. 3-8.

20. J. Webster and B. Goodwin, 1982, Journal of Social and Biological Structures, 5, 15-47; D.B. Wake and G. Roth, eds. 1989. Complex Organismal Functions. New York: John Wiley; K. Padian, 1989. Paleobiology1, 73-78; R.A. Raff and E.C. Raff, eds. 1987. Development as an Evolutionary Process. New York, Alan R. Liss, p. 8, S. Kaufman, 1985. Cladistics 1, 247-265; K.S. Thomson, 1988. Morpho Genesis and Evolution. New York: Oxford University Press; M.W. Ho and P.T. Saunders, 1979. J. Theoret. Biol. 78, 573-591; B. John and G. Miklos, 1988, The Eukaryote Genome in Development. London: Allen & Unwin.

21.Ho, M.W., & Saunders, P.T. (Eds.) (1984). Beyond Neo-Darwinism. London: Academic Press, p.ix.

22. See especially Thaxton, et. al, (1984); Ambrose, E.J. (1982). The Nature and Origin of the Biological World. New York: Wiley; Denton (1986); Walton (1977).

23. See, for example, W.H. Thorpe (1978). Purpose in a World of Chance: A Biologist's View. New York: Oxford University Press. Hoyle, F. (1983). The Intelligent Universe. New York: Holt, Reinhart & Winston. Kuznetsov, D.A. (1989). "Invitro Studies of Interaction between Frequent and Unique MNRAs and Cytoplasmic Factors from Brain Tissue of Wild Timber Wolves of Northern Euroasia," Clethrionomys Glareolus, Clethrionomys Frater and Clethrionomys Gapperi: A New Criticism to a Modern Molecular-Genetic Concept of Biological Evolution, International Journal of Neuroscience, 49: 43-59. Yockey, H. (1989). The Mathematical Foundations of Molecular Biology. New York: Cambridge University Press. Thaxton, C., Bradley, W. and Olsen, R. (1984). The Mystery of Life's Origin. Dallas: Lewis and Stanley. Ambrose, E.J. (1982). The Nature and Origin of the Biological World. New York: Halsted Press. Bolin, R. and Lester, L. (1984). The Natural Limits to Biological Change.