"What have they said to us?" "I could translate, but it would be meaningless. They have welcomed us in the name of their Emperor, who appears to be a… - Larry Niven

He’s a computer. Perfect memory, rigid logic, no judgment. I forgot. I talked to him like a human being, and now—

"They used to teach us that evolution of intelligent beings wasn't possible," she said. "Societies protect their weaker members. Civilizations tend to make wheel chairs and spectacles and hearing aids as soon as they have the tools for them. When a society makes war, the men generally have to pass a fitness test before they're allowed, to risk their lives. I suppose it helps win the war." She smiled. "But it leaves precious little room for the survival of the fittest."

For each human being there is an optimum ratio between change and stasis. Too little change, he grows bored. Too little stability, he panics and loses his ability to adapt.