When Allied soldiers fought their way across New Guinea and other Pacific Islands during World War II, Americans and Japanese were hardly the only cultures in conflict. Tribal peoples across Melanesia were caught up in the war as well. Acting as local guides and occasional surrogates for the warring sides, the tribesmen were exposed to the technological marvels of the 20th century for the first time. Countless convoys of airplanes supplied the war effort, bringing canned foods, advanced weapons, and modern medicines to isolated populations that lacked prior experience with this seemingly miraculous "cargo."

		Chris Beard is curator and head of vertebrate paleontology at the Carnegie Museum of Natural History and author of "The Hunt for the Dawn Monkey: Unearthing the Origins of Monkeys, Apes and Humans" (University of California Press, 2004).

Without any logical explanation for how these goods were produced and why foreigners were the only people who had them, the tribesmen concocted their own theory. Their account held that the ancestral spirits of the people of New Guinea had created these valuable commodities, to improve the lives of their descendants.

When the troops and transport planes went home after the war, local natives tried to appease these spiritual inventors by emulating the airstrips and control towers the soldiers had constructed. Using bamboo and palm fronds, the tribesmen fashioned runways and radio towers in the jungle, mistakenly believing that such shrines would cause the airplanes to return, along with their precious cargo.

Few of us would confuse the naivete of the New Guinea tribesmen with science. But the fundamentally human urge to explain the world around us -- how the Earth and its plant and animal life arose, how humanity came to occupy its privileged place in nature, and so forth -- transcends the boundaries of time and culture.

Anthropologists have found that origin myths are common to virtually all human societies. They vary in colorful ways from group to group, but they almost always invoke some supernatural being as the original creator of the Earth and its inhabitants.

Origin myths obviously fulfilled a deep psychological need among pre-industrial societies, and they linger on as important aspects of cultural identity in many groups and individuals today. They range from being vaguely plausible to wildly outlandish explanations for the nature of things, in much the same way that just-so stories about how the leopard got its spots can be seductively satisfying.

None of them, however, are scientific. The same goes for the vanilla-coated origin myth du jour known as "intelligent design."

Just as tribal people in New Guinea thought that mysterious cargo items were the handiwork of ancestral spirits, advocates of intelligent design claim that certain aspects of biology are so complicated and indecipherable that they can only be explained as the labor of an intelligent designer. Neither explanation qualifies as science. Why?

First and foremost, there is no logical connection between the observations to be explained (the sophistication of cargo items in New Guinea, biological complexity in the case of intelligent design) and the causal agent that is hypothesized to account for the observations (ancestral spirits in New Guinea, an unspecified but apparently intelligent designer in the United States).

Given this absence of logic, we can all rapidly generate long lists of alternative hypotheses that might be equally or even more compelling. We might, for instance, attribute biological complexity (or sophisticated cargo goods, for that matter) to God, Allah, Satan, ancestral spirits, the Great Pumpkin, Elvis, astrology or natural selection, to name but a few potential actors in an infinitely long list of possible suspects.

A fundamental role of science is to test and successively refute these multiple hypotheses, until the list gets sufficiently culled to become more manageable. Hypotheses that simply can't be tested -- like the hypothesis that God is the ultimate source of biological complexity -- do not meet the basic criteria of science. Those that withstand multiple and diverse bouts of testing -- like Darwin's hypothesis that life on Earth evolved over millions of years through natural selection -- get taken seriously, especially as more and more evidence accrues that points in the same direction.

Darwinian evolution has been tested so thoroughly and for so long that it now stands as a unifying principle upon which a great deal of other science rests.

My own branch of science, paleontology or the study of extinct organisms based on fossils, had progressed enough by 1877 that Professor O.C. Marsh of Yale University -- then one of its most prominent practitioners in the United States -- was able to proclaim in a famous keynote address to the American Association for the Advancement of Science that, "To doubt evolution today is to doubt science, and science is only another name for truth." Marsh delivered his speech in Nashville, Tenn., almost 50 years before that state hosted the famous Scopes "monkey trial" in 1925.

Scientifically, the Scopes trial was an anachronism long before the first witness was called. Today, the fossil record is immeasurably more complete than Marsh could ever have hoped. And every new discovery, from complete "feathered dinosaurs" in China to early African hominids that tear down the last few distinctions between the lineages leading to modern chimpanzees and humans, tests and reaffirms the validity of Darwin's theory.

Just last month, scientists announced that they had sequenced the entire chimpanzee genome for the first time, verifying once again the remarkable genetic similarity between humans and chimpanzees in accordance with Darwinian theory and the fossil record.

Why should any of this matter to the vast majority of Americans, those who live and work outside the ivory towers of museums and universities? Simply put, evolution is the cornerstone of modern biology and it leaves an equally important footprint on geology.

Both fields routinely rely on evolutionary theory in their quest to achieve practical benefits to society and economic growth for the nation. Pharmaceutical companies acknowledge that natural selection explains why certain bacterial strains become increasingly resistant to antibiotics.

Oil and gas companies employ experts on microscopic fossils contained in layers of sand and mud deep beneath the surface of the Earth to tell them where to drill. Orthopedic surgeons know that chronic lower back pain dates back to the moment that our ancestors decided to rise up and walk on two legs, rather than scurrying about on their hands and feet.

Scientific research and its practical applications have long been vital to the American economy. American leadership in science, after all, is what really produced the cargo that dazzled the New Guinea tribesmen and helped win the war in the Pacific.

Today, as our economy continues to evolve in the face of outsourcing of manufacturing jobs and other traditional sectors of employment, advances in science and technology buoy efforts to sustain our lifestyle and maintain our competitive edge in the global marketplace.

Even if we step back from the cutting edge of science, we find that employers -- particularly those in the most lucrative sectors of the economy -- demand higher levels of science literacy and technical proficiency when it comes time to hire new personnel.

Should the Dover Area School District prevail in the current court case over including intelligent design in its school curriculum, our fellow citizens to the east will learn to shuffle along to the same music that residents of Kansas danced to when their state's Board of Education introduced creationism into public school science classes several years ago.

Kansans discovered that companies were reluctant to set up shop in their state, because of a poorly educated work force and inadequate educational opportunities for the children of their employees.

Fellow Pennsylvanians, we have two choices.

We can reinvigorate our efforts to advance science literacy by demanding higher standards in our public schools, where evolutionary biology should be taught as an uncontroversial part of the curriculum. Those of us in the museum community can redouble our efforts to offer exhibits, lectures, and other programs explaining the attendant marvels of evolution to the public at large.

Alternatively, we can all march into the jungle and begin to fashion headphones out of coconuts while we wait for the cargo to return. Which will it be?