The most accomplished scientist called by the state to defend the Arkansas creation law today said that he thought most of the law was "claptrap" and that five of the six parts of the so-called creation science in the law were scientifically unsupportable.

As the Arkansas creation trial neared its end today, the state called Dr. N. K. Wickramasinghe, head of mathematics and astronomy departments at the University of Wales and a co-worker of the eminent British astronomer, Sir Fred Hoyle. On trial is a new Arkansas law that demands that creation science must be taught in public schools wherever evolution is taught.

Wickramasinghe, a scientific rebel who refuses to publish his theories in scientific journals because of what he calls their establishment bias, startled those in the courtroom with some of those theories.

Among other things, he said that he believes there is life inside comets, that diseases escape from comets and often infect the earth, and that life did not originate on the earth but was dropped here from some other source in the universe. He said he thinks it possible that insects are more intelligent than humans, but "they're not letting on that they're smarter because things are going so well for them."

Outside the courtroom, he said he believes that the theory of evolution is "evil . . . , an evil influence in the world that could account for the rise of Nazi Germany. It provides the moral and scientific justification for the bully to survive."

He said that he came all the way from Wales to support the creationists, not because he believes their creation science is correct, but because of his political belief that people of Arkansas ought to be able to demand and get taught in school whatever belief they want.

But he said that if he were a teacher in Arkansas, "and I was presented with this law, I would be very unhappy. Certain aspects of the law are demonstrably wrong, not good science, and should not be taught."

Wickramasinghe testified that his experiments have shown that it is conceivable that there are microorganisms living in the interior of comets, and that this life is rained down on the earth from space whan a comet passes by.

He said that one such passage brought life to the earth, and that succeeding passages brought genes to the earth that allowed new species to develop.

He said that he thought that most of the ideas of creation science--including a young earth, a worldwide catastrophic flood, the creation of plants and animals fully formed, and a separate ancestry for man and apes --were "claptrap." But he did agree with the creation scientists on the point that the theory of evolution cannot explain the appearance of life and of new species over the eons.

Attorney General Steve Clark, who is defending the Arkansas law, said he called Wickramasinghe as a witness to show that various ideas of "creation science," including Wickramasinghe's, have some scientific basis and can be taught under the "creation model" rather than the "evolution model."

Wickramasinghe's testimony was also intended to cast doubt on the commonly accepted scientific view that life could have arisen from chemicals early in the earth's history. As a mathematician, he said the odds that the necessary chemical combinations could occur from the random motion of molecules were about the same as the odds that "a tornado blowing through a junkyard would assemble a Boeing 747."

On cross-examination, he admitted that the odds that 50,000 people would come together in one configuration, as a crowd at a football game, would be even less likely.

"But that happens every weekend, doesn't it?" asked the lawyer cross-examining him. "Yes," he said, but added that he thought the two calculations were not mathematically comparable.

As one example of his theory of life dropping from space, Wickramasinghe cited an outbreak of influenza at Eton school in England.

"Do you have any unequivocal evidence that there is DNA or organisms in space?" he was asked. "No," he said.

". . . But you believe that school children caught a cold from a comet?"

Wickramasinghe laughed. "That is so."