A witness for the state of California testified today that science teachers are careful not to violate the religious freedom of students by asking them to believe in evolution if it conflicts with their religious beliefs.

Taking the stand for the defense on the fourth day of the California evolution trial, biology teacher John Horn said, "I have students who are very upset about evolution. I've had students on a test answer, 'I know this is what you want, but I don't believe it.'" This kind of answer is acceptable, Horn said, "Because a child only needs to understand what is presented, not believe it."

"All we are concerned with now," Judge Irving Perluss said, "is whether someone's religious liberties are offended" by the manner in which evolution is taught in the schools. "It doesn't matter how absurd those beliefs are, if they are sincerely believed," he said.

The judge, who has interrupted the trial frequently with questions for witnesses, asked state witness William Mayer, a biologist and director of the Biological Science Curriculum Study, if a preface written into textbooks or the state science teaching guidelines would be an acceptable way to assure that no religous liberties are violated in teaching evolution.

Would you approve, the judge asked Mayer, of a preface that said, "This [biology book] does not deal with theology."

Mayer agreed that there should be a clear explanation of that, "and throughout the book clear statements" could be made to the same effect: "That what we are dealing with is science [rather than theology]," Mayer said.

The judge quickly asked the court stenographer to make a typewritten copy of the exchange.

The defense spent today arguing that neither the texts, nor the state science teaching guidelines, nor the way they are used in the classroom amounts to a "dogmatic" or "insensitive" teaching of evolution. "I have several students who bring their Bibles to class . . . ," Horn said. "We discuss it back and forth . . . . I've had students prepare papers on [creationism versus evolution], and we've had debates in class."

"Do students have to accept evolution to get a good grade?" the defense asked.

"No, not in my class. . . ."

The court is to decide whether the religious rights; of the children of Kelly Segraves, a plaintiff in the case, have been violated by the way evolution is taught in school. Then, if the judge agrees that the plaintiffs' rights have been violated, an "accommodation" must be worked out to assure that further violations don't occur.

Apparently realizing that creationists were not likely to win the right to have their views taught side by side with evolution in public schools, the plaintiffs' attorney altered his case in mid-trial.

The judge said the change reduced the case from what he called a classic and important confrontation over whether creationism is a theory that ought to be taught in public school, to the simpler question of whether 13-year-old Kasey Seagraves and children like him have their religious liberties offended by the manner in which evolution is taught.

But still the crowds have gathered at the courtroom door three hours before they open, and the hallways remain filled every day with spectators from both sides, haggling endlessly over science and the words of the Bible.

Creationists continue to believe that the trial is important to their cause.

As Robert Kofahl, science adviser to the creationist educational group plaintiff Kelly Segraves runs, put the matter. "If we win it will be a big step in the right direction. We will be back, because we hope to end the teaching of a non-science [evolution] in science classes. But we have a whole culture to educate, so it may take some time."