HARRISBURG -- A federal trial that could have a bearing on how evolutionary theory is presented to public school students began here yesterday, with a judge hearing opening statements for and against the discussion of "intelligent design" in science classes.

Mostly, the statements were against it, as the trial's first day focused on testimony from Kenneth Miller, a biology professor at Brown University. He is testifying for the plaintiffs suing York County's Dover Area School District.

Eleven parents, represented by the American Civil Liberties Union and other attorneys, are seeking to overturn the district's controversial -- and possibly one-of-a-kind -- addition to the ninth-grade biology course.

Last autumn, Dover's school board instructed ninth-grade biology teachers to tell students that the theory of evolution has unexplainable gaps, and that "intelligent design," which says biology's complex machinery presents evidence of an intelligent creator, "is an explanation of the origin of life that differs from Darwin's view." The policy took effect in January -- some of the students were allowed to opt out of hearing the short statement.

Miller is an oft-recruited defender of evolution, and has written several articles and trade books explaining evidence for evolution, reconciling his scientific views with his religious ones and panning the concept of intelligent design. He is also the author of one of the top-selling high school biology textbooks.

Yesterday, amid several hours of testimony and slide show graphics, Miller said that "intelligent design is not science, and it cannot be construed as a scientific theory whatsoever."

The question of whether intelligent design is itself a scientific theory, or is merely posing as one while taking pokes at another theory, will be one of the main issues considered by the court.

If the plaintiffs can convince the judge that intelligent design is inherently religious, even though supporters try not to name the creator, the school board policy may violate the Constitution's church-state separation clause, not to mention years of case law.

But if the defendants can show that intelligent design is not religious, the amendment to the curriculum may slip through.

Attorneys from the Thomas More Law Center, which is defending Dover Area, tried in opening statements to paint the change to the science curriculum as a minor one. In fact, attorney Pat Gillen no fewer than six times referred to the intelligent design statement as a "modest" change to the district's biology course, having nothing to do with God.

"Creationism and intelligent design are two different things," Gillen said. This case, he said, is not about church-state separation, but instead about the "freedom of academic inquiry."

But in the plaintiff's opening statement, attorney Eric Rothschild tried to show that the school board members in Dover were religiously motivated. In a barrage of school board memos, and in one video clip, Rothschild showed that the board had often discussed injecting "creationism" into the science curriculum.

That's key, because "creationism" and "creation science" already have been rejected by the courts when proponents have tried to insert those terms into public school lesson plans. Rothschild wanted to show that intelligent design is similar to creationism, and that the board used the terms interchangeably.

"That's their word -- creationism," he said. "Board members, in starkly religious terms, changed the science curriculum to advance a specific religious viewpoint," and have imposed that viewpoint on their students.

Once Miller was on the stand, he was called upon to summarize a book called "Of Pandas and People," a text that presents intelligent design on a high school reading level. The book is in the Dover library, and the board statement invited students to look at the book if they wished to.

Miller examined several of the book's arguments -- that complex biological systems point to an intelligent designer, that Darwin is wrong about the evolutionary tree -- and picked them apart.

Pandas, he concluded, "is inaccurate [or] downright false in every section of the book."

He also said the four-paragraph statement, despite its brevity, is damaging, because it sets up a "false duality" for students -- they must pick between the "atheist's" textbook, or the "Bible-friendly" one.

Today, Miller remains on the stand, to be cross-examined by Dover's defense team.

The nonjury trial, Kitzmiller v. Dover Area School District, is expected to last five weeks, said U.S. District Judge John E. Jones III.