Wednesday, October 28, 2009

Evolution: theory or fact?

In writing Imperfect Oracle, which deals with how science exercises influence, or fails to do so, in contemporary society, I was struck many times by the challenges science faces in communicating its outlook. It is widely understood that communication is critical in determining science’s place in society. Much has been written on how scientists and the science establishment generally need to do better than they have done. The American Association for the Advancement of Science (AAAS) does a great deal at its annual meeting to present thoughtful commentary on important issues that affect society at large. This is but one venue, and it has limited reach into most peoples’ consciousness. One hopes that the program and others like it, such as the national meetings of the American Chemical Society, will be noticed and reported on by those who shape the content of internet, TV, cable and print media. Even when science content appears on these outlets, however, not much insight into how scientists actually learn about the world, or how their work leads to new scientific knowledge, goes with it.

As I show in the book, such insight is essential to establishing science’s authority when there is an inconsistency between what science has to say on some topic and what people hold as part of their core cultural understandings. An example came up this past weekend. Nicholas Wade has written a review of Richard Dawkins’s new book, The Greatest Show on Earth, in which he argues that Dawkins failed to appreciate the distinction between a theory and scientific fact in talking about the status of evolution. Those who wish to dismiss evolution as “just a theory” employ the notion of a theory as something supported by evidence but inescapably incomplete and always subject to refutation at some level. This view in varying degrees has dominated much of the philosophy of science for decades. Dawkins will have none of that; for him evolution is a “fact in the same sense as it is a fact that Paris is in the Northern Hemisphere.” Wade suggests a way of thinking about evolution that avoids Dawkins’s dogmatic stance, but in doing so he moves to an account that philosophers of science are likely to find wanting. Indeed, in the Letters section of the following week’s issue of the Review of Books, the philosopher of science Philip Kitcher wrote to defend Dawkins. He argues that evolution is a theory because it is a general systematic explanation, and because it accounts for such a vast amount of relevant experimental data “it may be accepted without debate.”
Perhaps, then evolution is a “fact” in the same sense as Paris’s location. But this rather facile response bothers me. The term “evolution” has meaning at many levels. There is the general theory grounded in Darwin’s original idea that organisms have evolved through time. Evolution in that sense can be traced in a paleontological record so extensive and self-consistent that, as Kitcher suggests, there is really no room for reasonable doubt. At the same time, evolution is a vital part of modern biology, and new insights relating to it are reported frequently. New technologies in biology have given rise to experiments that have required new interpretations of what “evolution” means in particular cases. Think, for example, of the contributions from molecular phylogenetics, which relates organisms in terms of the similarities in their DNAs. In other words, evolution is not a dead science, and in this sense it does not have the status of accepted fact. We need to be careful not to muddle our notions of what we mean by theory in a vain effort to make “evolution” impregnable to the objections of the congenitally unconvinced.

The truth is that arguments with creationists and others who fail to accept the claims of modern science will not be settled for the great audience of uncommitted nonscientists when one side or the other lands a telling blow. Daniel Dennett, in his letter preceding Kitcher’s in the Review of Books, wonders how the judge’s decision in the famous Dover, Pa. case of a few years ago can have failed to convince The Times that the intelligent design campaign is a hoax unworthy of any news space. He must be aware that within a week or so of the Dover decision the Discovery Institute had issued a book-length rebuttal. It is altogether like swatting flies; one of course should swat, but not really expect flies to disappear. The Times is a newspaper, not an arbiter of science wars. What is at issue here is how science can establish its epistemic and moral authority in society outside the scientific community. How can it bring people to the point of openly considering what science has to tell us about the world when its findings conflict with settled cultural biases and cognitive leanings? Science has not done well at engaging people in terms that have meaning for them. In his fine little book, The Culture of Education, Jerome Bruner wrote about what we need to do to equip people for participation in the full range of the culture in which they live. Science must learn how to be part of that challenging educational project in ways that it has not been in the past. As I have explained in Imperfect Oracle, it has a lot of difficult, uphill work to do.

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