Prove it!

Natural History, Sept, 2005 by Peter Brown

Bobby R. Harrison took part in the first confirmed sighting of an ivory-billed woodpecker in the United States in fifty years. By his own admission ("Phantom of the Bayou," page 18), the experience of rediscovering a bird long presumed extinct was so emotionally overpowering that Harrison broke down and cried; ever since, he's been known as Sobbin' Bob. Harrison was one of seventeen coauthors of a paper, announcing the reappearance of the ivory-bill, in the journal Science this past June; the news has become the biggest bird story of the year. Yet shortly before we went to press, Harrison's vivid first-person account seemed in danger of unraveling. Three respected biologists were questioning the evidence that the bird still existed.

Now Harrison has been vindicated. New audio recordings of a bird calling are so clear that even the skeptics have become convinced the sound is an ivory-bill. The Cornell University Laboratory of Ornithology has promised Natural History that the recordings are being posted on the Web (birds.cornell.edu/ivocy) around August 28, after we go to press.

The ivory-bill aside, stories in Natural History are not usually the stuff of the evening news. So it's curious to find a second item in the mainstream news so pertinent to the topics we cover. President Bush has apparently endorsed the idea that "intelligent design" should be taught as a full-fledged theory, on a par with evolution.

This is not the place to lay out claims and counterclaims about how life originated on Earth; we plan to do that, soon enough. But it is worth saying why intelligent design has utterly failed to engage the scientific community. The problem is not that it is wrong; the problem is that it can't be tested, proved, refuted, or falsified. Intelligent design doesn't risk being wrong. That's what makes it a matter of faith, not science.

Our cover story this month, Robert R. Dunn's article on ants, seeds, and convergent evolution ("Jaws of Life," page 30) offers an instructive illustration of the point. The seeds of vast numbers of plant species have small appendages that seem suited only for attracting ants. To an ant, the appendage is baby food. To a seed, the ant is a means of dispersal. So is each encounter of ant with seed the result of intelligent design? Maybe--how could you ever prove it wasn't?

But get down on your hands and knees with Dunn, turn over a rock, and watch the behavioral details unfold. Each step is no more deliberate than the falling of a stone, yet the steps taken together, over millions of years and uncounted trillions of ants and seeds, have given rise to a complexity that would be easy to mistake for an act of will. The mere existence of complexity, though, is no proof that it was intended: complexity can arise from the commonest elements. As a team manager in the 1988 movie Bull Durham says, with deep irony, about baseball: "[It's] a simple game. You throw the ball, you hit the ball, you catch the ball."

Our popular "Universe" columnist, Neil deGrasse Tyson, is taking a well-earned break from the lineup. Neil returns to our pages next month.