As the debate over “intelligent design” continues in a Pennsylvania courtroom comes this fascinating snapshot of American public opinion:

The latest USA Today/CNN/Gallup Poll says that a majority of Americans, 53 percent, believe that God created human beings in their present form exactly as described in the Bible. Man, from the dust of the earth. Woman, from man’s rib.

A scant 12 percent think that human beings evolved without an assist from God. The rest seem to choose some sort of middle ground, giving God a supporting role in an evolutionary process that’s gone on for millions of years.

Not so surprising in a country that’s debated the validity of evolution longer than you can say William Jennings Bryan.

It may not even surprise you to learn that Protestants are “way more likely to be biblical literalists than anyone else, including Catholics.”

But here’s the uncomfortable revelation: Opinion on evolution is broadly correlated to income. Those in the lowest income brackets are twice as likely to view the Adam and Eve story as incontrovertible fact than are those at the top of the salary scale.

You might say: This is only a poll, only a snapshot. True. But the picture here is echoed in other surveys that have found a sharp difference in views on evolution and creationism based on education level. College graduates are twice as likely as those with just a high school diploma to accept the natural-selection theory of evolution.

Polite company generally tries to change the subject when such observations are raised. We are still distinctly uncomfortable when noting the connection between class and education, but it exists: The more money you have, the more likely you are to be better educated, the more likely you are to have attained an understanding of and appreciation for scientific knowledge.

And this debate over the teaching of evolution rests on knowledge. Some issues in America’s so-called culture wars are, in essence, a matter of opinion. Should abortion be allowed and under what circumstances? Should gay marriage be permitted? Is it moral to maintain the death penalty?

Since these are matters of opinion, Americans do what Americans generally do, and that is try and fumble their way toward a middle ground. So a majority of Americans believe abortion should remain legal, but with restrictions. Gay marriage is still largely unacceptable, but other sorts of gay unions are more readily embraced.

The “intelligent design” debate is different. First, let’s call it what it is: ID is a proxy for a kind of creationism that may not be literally biblical but posits that an intelligent creator designed the world and still keeps a hand in its management.

Proponents of intelligent design have made not a single verifiable or refutable scientific claim. That is why it is not considered science. If it’s not testable, it’s not science, and ID has never been independently tested.

It sounds reasonable and even harmless, and it surely appeals to the faith instincts of many people, but it is ultimately a matter of belief, not fact. As the polls show, this crucial distinction between science and faith is recognized more frequently by those with higher education.

In one survey, for instance, nearly half of those who believe in creationism think the scientific community is divided over the evolution question. That’s just plain wrong. The scientific community overwhelmingly accepts evolutionary theory, unless or until something better comes along.

“We used to have a lot more deference in this country for those who knew more than us,” notes Alan Wolfe, director of the Boisi Center for Religion and American Public Life at Boston College.

“In the last 30 years, we have become less deferential, much more populist, and in many ways, I’m glad because we’re more open and less elitist,” Wolfe says. “But you lose something when you lose deference.”

And we will lose a great deal if growing numbers of Americans are led to distrust facts and deride the rigorous, independent, continually testable searching that science demands.

Knowledge can make us uncomfortable. Adam and Eve found that out quickly enough. But the search for knowledge also makes us human.