this fact with ritual-taboo?"

"Well, once a belief gains a foothold," Stanton said, "it is very
difficult to wipe it out, even among human beings. Among Nipes, it would
be well-nigh impossible. Once a code of ritual and of social behavior
had been set up, it became permanent."

"For example?" Yoritomo urged.

"Well, shaking hands, for example," Stanton said after a pause. "We
still do that, even if we don't have it fixed solidly in our heads that
we _must_ do it. I suppose it would never occur to a Nipe not to perform
such a ritual."

"Just so," Yoritomo agreed vigorously. "Such things, once established in
the minds of the race, would tend to remain. But it is a characteristic
of a ritual-taboo system that it resists change. Change is evil. Change
is wrong. We must use what we know to be true, not try something that
has never been tried before. In a ritual-taboo system, a thing which is
not ritual is, _ipso facto_, taboo. How, then, can we account for their
high technological achievements?"

"The pragmatic engineering approach, I imagine," Stanton said. "If a
thing works, then go ahead and use it. It is usable. If not, it isn't."

"Approximately," said Yoritomo. "But only approximately. Now it is my
turn to lecture." He put his pipe in an ashtray and held up a long, bony
finger. "Firstly, we must remember that the Nipe is equipped with a
functioning imagination. Secondly, he has in his memory a tremendous
amount of data, all ready at hand. He is capable of working out theories
in his head, you see. Like the ancient Greeks, he finds no need to test
such theories--_unless_ his thinking indicates that such an experiment
would yield something useful. Unlike the Greeks, he has no aversion to
experiment. But he sees no need for useless experiment, either.

"Oh, he would learn, yes. But once a given theory proved workable, how
resistant he would be to a new theory. Innovators, even in our own
culture, have a very hard time working against the great inertia of a
recognized theory. How much harder it would be in a ritual-taboo society
with a perfect memory! How long--how _incredibly_ long--it would take
such a race to achieve the technology the Nipe now has!"

"Hundreds of thousands of years," said Stanton.

Yoritomo shook his head briskly. "Puh! Longer! Much longer!" He smiled
with satisfaction. "I estimate that the Nipe race first invented the
steam engine not less than ten million years ago!"

He kept smiling into