Under the tube at Rikud's left lay Crifer. The man was short and heavy through the shoulders and chest, and he had a lame foot. Every time Rikud looked at that foot, it was with a sense of satisfaction. True, this was the only case of its kind, the exception to the rule, but it proved the world was not perfect. Rikud was guiltily glad when he saw Crifer limp. But, if anyone else saw it, he never said a word. Not even Crifer. * * * * * Now Crifer said, "I've been reading again, Rikud." "Yes?" Almost no one read any more, and the library was heavy with the smell of dust. Reading represented initiative on the part of Crifer; it meant that, in the two unoccupied hours before sleep, he went to the library and listened to the reading machine. Everyone else simply sat about and talked. That was the custom. Everyone did it. But if he wasn't reading himself, Rikud usually went to sleep. All the people ever talked about was what they had done during the day, and it was always the same. "Yes," said Crifer. "I found a book about the stars. They're also called astronomy, I think." This was a new thought to Rikud, and he propped his head up on one elbow. "What did you find out?" "That's about all. They're just called astronomy, I think." "Well, where's the book?" Rikud would read it tomorrow. "I left it in the library. You can find several of them under 'astronomy,' with a cross-reference under 'stars.' They're synonymous terms." "You know," Rikud said, sitting up now, "the stars in the viewport are changing." "Changing?" Crifer questioned the fuzzy concept as much as he questioned what it might mean in this particular case. "Yes, there are less of them, and one is bigger and brighter than the others." "Astronomy says some stars are variable," Crifer offered, but Rikud knew his lame-footed companion understood the word no better than he did. Over on Rikud's right, Chuls began to dress. "Variability," he told them, "is a contradictory term. Nothing is variable. It can't be." "I'm only saying what I read in the book," Crifer protested mildly. "Well, it's wrong. Variability and change are two words without meaning." "People grow old," Rikud suggested. A buzzer signified that his fifteen minutes under the rays were up, and Chuls said, "It's almost time for me to eat." Rikud frowned. Chuls hadn't even seen the connection between the two concepts, yet it was so clear. Or was it? He had had it a moment ago, but now it faded, and change and old were just two words.