"When did you begin to understand?"
"They simply taught all of history to me. Including the part about myself. Then I began to get the picture. Funny. I wound up teaching them a lot of history."
"I bet you know a lot."
"I do," the man with the Asiatic features said modestly. "Anyway, they finally got across to me that in the 22nd century—they had explained the calendar to me, too; I used a different one in my day—they had learned how to grow new limbs on people who had lost arms and legs."
"That was the first real step," said the girl.
"It was a long time till they got to the second step," he said. "They learned how to stimulate life and new growth in people who had already died."
"The next part is the thing I don't understand," the girl said.
"Well," said the man, "as I get it, they found that any piece of matter that has been part of an organism, retains a physical 'memory' of the entire structure of the organism of which it was part. And that they could reconstruct that structure from a part of a person, if that was all there was left of him. From there it was just a matter of pushing the process back through time. They had to teach me a whole new language to explain that one."
"Isn't it wonderful that intergalactic travel gives us room to expand?" said the girl. "I mean now that every human being that ever lived has been brought back to life and will live forever?"
"Same problem I had, me and my people," said the man. "We were cramped for space. This age has solved it a lot better than I did. But they had to give me a whole psychological overhauling before I understood that."