THE DECLARATION by President Bush that ''intelligent design" should be discussed in the classroom as a counterpoint to the theory of evolution has pushed the issue to the forefront of the unfortunately named ''war" between science and religion.
Not that the proponents of ID accept, at least openly, a religious label. They claim that ID is science and should be treated as such. After all, they don't state that the designer is God. It can be any kind of intelligence, just bright and powerful enough to create the amazing complexity of life: We (or our bacterial ancestors) are the lab rats in an ongoing experiment. According to some ''IDists," the possibility that the designer is an extraterrestrial intelligence should not be neglected. I will try to convince you that it should.
Some of my colleagues think that what I am doing right now is wrong; that for a scientist to discuss the issue is to give it a credibility it doesn't deserve. They refuse to participate in roundtable discussions with IDists, claiming that the effort amounts to a huge waste of time, that those who support intelligent design do so for reasons that are not scientific and that no 60-minute or lifelong discussion would change their minds.
I disagree. It's true that arguing rationally with those who blindly believe in ID or anything else is impossible. Extremists of any sort are deaf to reason. But this is not the audience scientists should have in mind. They should be targeting the millions of others who sit on the fence, confused and curious, wondering why the heck scientists, who are so sure of their theories, don't appear publicly to demolish the IDists for once and for all. But while scientists remain mostly silent, creationists and IDists proclaim their ''truths" for all who want to hear them. Scientists need to speak up.
A hypothesis is scientific if it can be empirically validated. One must ''see to believe" -- exactly the opposite of the ''believe to see" which forms the premise of many religious systems. It's much easier to see miracles everywhere if you believe in them. The scientific ''see to believe" is supported by data acquired in the lab or through observations. If the hypothesis is vindicated, the scientific community, after much debate, accepts it. This doesn't mean it will remain part of the established ''truth." New theories sprout through the cracks of old ones. Science needs crisis to evolve. It needs mysteries. It is always incomplete. Behind our ignorance there is just the science we haven't yet developed.
Here is an example. Late in the 19th century, it was known that Mercury's orbit shifted very slowly, like a wobbling top. The orbit's behavior was a mystery, and Newton's theory of gravity couldn't describe it. Astronomers even invented an imaginary planet between Mercury and the Sun to explain the anomaly.
In 1916, Einstein proposed a new way to think about gravity, his general theory of relativity. Instead of Newton's mysterious action-at-a-distance, Einstein suggested that space was plastic, that matter could bend and stretch it like a rubber sheet. Einstein's theory explained Mercury's wobbling as a consequence of the bending of space near the Sun. New science resolved an old mystery. Does this mean that Einstein's theory is the last word in gravity? No. Eventually, it will be modified by a more powerful theory capable of explaining things it cannot.
The ID hypothesis, that we, or a few key steps in the evolution of life, are products of purposeful design is not scientific. There is no way to test it. It cannot be confirmed experimentally. The statement that life is too complex to have happened by chance and that we are somehow fundamentally incapable to understand how reflects a deeply unscientific attitude, a put-down of human reason. The uncertainties of today are tomorrow's new science.
If I had the opportunity to meet the assumed designer, I'd ask what, to me, is the most important question of them all: ''Mr. Designer, who designed you?"
If the designer answers that it doesn't know, that perhaps it was also designed, we fall into an endless regression, straight back to the problem of the first cause, the one that needs no cause. At this point the mask tumbles and we finally discover the true identity of the IDists' Designer. We should capitalize the word, as this is how we are taught to refer to God.
Marcelo Gleiser, a professor of physics and astronomy at Dartmouth College, is the author of ''The Prophet and the Astronomer: A Scientific Journey to the End of Time." He is currently working on a biographical novel of Johannes Kepler.