he defense of the Arkansas creation law opened today with a spectacular courtroom fireworks display as the opening creationist witness described, under cross-examination, his belief in unidentified flying objects, demon possession and the occult, which he said he sees as actual satanic attacks in the world.

The trial will decide the constitutionality of a new Arkansas law requiring that wherever evolution is taught in public school the so-called "creation-science" be taught also.

The creationist case began with Norman Geisler, professor of theology at the Dallas Theological Seminary and a small, cherubic-looking man who wore a tweed suit and spoke out from the witness box with a loud, clear voice. He opened by outlining under direct examination his belief that the concept of a creator can be non-religious.

During direct questioning Geisler offered his definition of religion.

There are religions that replace God with an idea, he said, such as religious humanism, which "centers its commitment in man." He said evolution has also been turned into a religion by some, including Charles Darwin and Alfred Russell Wallace, a co-discoverer of evolution in Darwin's time.

Geisler said that at the end of Darwin's life Darwin had said that natural selection was his God, in effect.

Geisler said also that one "can have the idea of God without religion," such as the "first cause" or "unmoved mover," which Aristotle believed in as scientific principle but not as a deity.

"Belief that there is a God has no religious significance," Geisler said, "belief that there is a creator has no religious significance." It is only committing oneself to God or worshipping him that makes the idea of a creator religious rather than scientific, he said.

This testimony is crucial to the state's defense of its creationism law, because the law implies a God or creator's existence as the author of the world in the creation-science view.

The Arkansas law defines creation-science as the "scientific evidences" for a sudden creation of the earth and the universe, all at once and fully formed, a very short time ago, geologically. It also calls for the existence of a worldwide flood, parallel to the flood of Noah in the Bible.

Teaching religion in public school has been declared unconstitutional, so the state is trying to show that the ideas of a creation and God are not necessarily religious.

Geisler admitted that later fundamentalists, after about 1920, became "militant, narrow, bigoted . . . and anti-intellectual." But he said in its original form, fundamentalism could accept science and even evolution without believing it disturbed their religion.

Now, he said, "scientific creationism" of today represents a return to the earlier enlightened attitude. Creationists now say, "Let's teach it as a scientific theory," Geisler said.

Then American Civil Liberties Union attorney Anthony Siano cross-examined Geisler, attacking his credibility. Siano began with sharp questions, and when he received equivocal answers turned quickly to Geisler's own words on the same questions laid down in a pretrial deposition.

Do you believe in the strict factual inerrancy of the Bible, Siano asked.

Yes, Geisler said, he believes in the factual inerrancy of the Bible.

"What is your understanding of the meaning of the term Satan," Siano asked with a sharp, hissing emphasis on the word Satan.

God created "good spiritual beings called the angels," Geisler said. Some of the angels rebelled and were led by one in particular, called Satan.

Siano asked sharply, "Do you believe in Satan?"

Geisler responded yes.

Siano asked what led Geisler to this belief.

Such things as the occult, such as Satan's moving objects in the world, Geisler said.

" . . . Demon possession, exorcism, occult activities . . . . I don't know what else you want me to say," Geisler continued softly, his cheeks flushed.

"Do you believe in UFOs?"

Geisler began a long answer about evidence for them, but Siano pressed until Geisler said simply, "Yes, I believe UFOs exist."

How are UFOs connected to your religion? asked Siano.

"UFOs are a satanic manifestation in the world for the purpose of deception," Geisler responded.

"No more questions," said Siano.

The trial continues Monday with more witnesses who support the law.