Tuesday, August 19, 2008

Why We Should Study Evolution

Olivia Judson offers three reasons in a New York Times opinion piece why evolution should be taught in our schools. I agree with her conclusion, but her reasons are riddled with confusions.

First, she makes the same error that so many make by contrasting evolution and intelligent design. ID is not incompatible with evolution. It's incompatible with the belief that evolution is a purposeless, random process guided only by unintelligent forces. Perhaps the most prominent of ID theorists, Michael Behe, believes in descent by modification. So do many others.

Judson then makes the claim that because there's controversy over evolution, "[I]t's discussed as though it were an optional, quaint and largely irrelevant part of biology. And a common consequence of the arguments is that evolution gets dropped from the curriculum entirely."

I would certainly like to see the data she relies on to make this assertion. I can't imagine that there's a public school anywhere in America that has dropped evolution from the curriculum, nor do ID people want them to.

Having raised our suspicions about her reliability on this topic, Ms Judson goes on to offer three reasons why evolution should be taught:

First, it provides a powerful framework for investigating the world we live in. Without evolution, biology is merely a collection of disconnected facts, a set of descriptions.... Add evolution - and it becomes possible to make inferences and predictions and (sometimes) to do experiments to test those predictions.

Fair enough. Evolution provides a coherent framework for thinking about relationships, but evolution can be taught without the materialism, and despite what Judson says, biology can be taught from a creationist perspective with no reference to the idea of common descent at all. Indeed, most of the actual evidence we have of evolution fits both models equally well.

The second reason she gives for teaching evolution is that "the subject is immediately relevant here and now. The impact we are having on the planet is causing other organisms to evolve - and fast."

Hunting animals to extinction may cause evolution in their former prey species. Experiments on guppies have shown that, without predators, these fish evolve more brightly colored scales, mature later, bunch together in shoals less and lose their ability to suddenly swim away from something. Such changes can happen in fewer than five generations. If you then reintroduce some predators, the population typically goes extinct.

Thus, a failure to consider the evolution of other species may result in a failure of our efforts to preserve them. And, perhaps, to preserve ourselves from diseases, pests and food shortages. In short, evolution is far from being a remote and abstract subject. A failure to teach it may leave us unprepared for the challenges ahead.

This is rather fevered rhetoric. In the first place what she's calling evolution here is not evolution as it's understood by most people. No one doubts that small changes can occur in populations of organisms because of stresses in their environment. Nor does anyone oppose teaching what we know about such variation (usually called microevolution). The controversy is over whether natural unguided forces can produce the molecules-to-man kind of evolution (macroevolution) that most people think of when they hear the word "evolution".

The third reason to teach evolution, Ms Judson tells us, is more philosophical:

It concerns the development of an attitude toward evidence. In his book, "The Republican War on Science," the journalist Chris Mooney argues persuasively that a contempt for scientific evidence - or indeed, evidence of any kind - has permeated the Bush administration's policies, from climate change to sex education, from drilling for oil to the war in Iraq. A dismissal of evolution is an integral part of this general attitude.

Moreover, since the science classroom is where a contempt for evidence is often first encountered, it is also arguably where it first begins to be cultivated. A society where ideology is a substitute for evidence can go badly awry.

This is plainly ridiculous. The science classroom is often the one place in our postmodern world where evidence is actually honored. If anyone is impervious to evidence it's the evolutionary materialists who believe steadfastly in their theory despite the lack of evidence for it. By this I mean that there's no evidence that blind, undirected forces plus chance are capable of creating a universe fit for life, originating life, or evolving the complex structures and pathways that are ubiquitous in living things. Nevertheless, every materialist believes that it happened despite the enormous odds against it and the total absence of evidence that it did.

But for me, the most important thing about studying evolution is something less tangible. It's that the endeavor contains a profound optimism. It means that when we encounter something in nature that is complicated or mysterious, such as the flagellum of a bacteria or the light made by a firefly, we don't have to shrug our shoulders in bewilderment.

Instead, we can ask how it got to be that way. And if at first it seems so complicated that the evolutionary steps are hard to work out, we have an invitation to imagine, to play, to experiment and explore. To my mind, this only enhances the wonder.

Very well, but this is an aesthetic reason for studying evolution. Why couldn't someone reply that the mystery of nature fills him with far more wonder when he considers that these things were engineered just for our enjoyment by a loving Creator? If a sense of wonder and optimism is to serve as justification for teaching something should we not insist that the view that there is a purpose underlying the world we study also be taught?

It's interesting that Ms Judson nowhere argues that we should study evolution because it's true. This, of course, would be the salient reason for including it in the curriculum, but its truth is, despite the adamantine asseverations of its proponents, notoriously difficult to establish.

Nevertheless, I agree that we should study evolution but for a reason having little to do with those advanced by Ms Judson. It should be studied because most practicing scientists believe some version of it, and we should therefore examine the theory and the evidence both for and against it in order to be familiar with the current state of scientific thinking. If and when it falls out of favor and is no longer thought to be true then we should no longer spend time on it, other than as a historical curiosity, regardless of whether it still performs the functions adduced by Ms. Judson.

RLC