"I think I know," said Docchi at last, still frowning. "Consider the gravity-generating plant. Part of it is an electronic computer, capable of making the necessary calculations and juggling the proportion of power required to produce, continuously, directed or undirected gravity. In other words, a brain, a complex mechanical intelligence. From the viewpoint of that intelligence, why should it perform _ad infinitum_ a complicated but meaningless routine? It didn't know why, and because it didn't, very simply, it refused to do so. "Now consider Nona. She's deaf, can't speak, can't communicate. In a way she's comparable to the gravital computer. Like it, she has a very high potential intelligence. Like it, she's had difficulty grasping the facts of her environment. Unlike it, though, she has learned something. How much, I don't know, but it's far more than the Medicouncil psychologists credit her with." "Yeah," said Jordan dubiously. "But what's happening now?" "If there were two humans involved, you would call it telepathy," answered Docchi hesitantly, fumbling for concepts he could only sense without grasping. "One intelligence is electronic, the other organic. You'll have to coin a new term, because the only one I know is extrasensory perception, and that's obviously ridiculous. It is, isn't it?" Jordan smiled and flexed his arms. Under the shapeless garment his muscles rippled. "It isn't," he said. "The power was there, but we're the only ones who know how to use it. Or rather Nona is." "Power?" repeated Anti, rising majestically. "You can keep it. I want just enough to get to Centauri." "I think you'll get it," Docchi promised. "A lot of things seem clearer now. For example, in the past, why didn't gravital units work well at considerable distances from the Sun? As a matter of fact, the efficiency of each unit was inversely proportional to the square of the distance between it and the Sun. "The gravital computer is a deaf, blind, mass-sensitive brain. The major fact in its existence is the Sun, the greatest mass in the Solar System. To such a brain, leaving the Solar System would be like stepping off the edge of a flat world, because it couldn't be aware of stars. "Now that it knows about the Galaxy, the drive will work anywhere. With Nona to direct it, even Sirius isn't far away." "Doc," said Jordan carelessly, "you'd better be figuring a way to get off the ship. Remember, we're going faster than man ever went before." He chuckled. "Unless, of course, you _like_ our company and don't want to leave." "We've got to do some figuring ourselves," interposed Docchi. "Such as where we are heading now." "A good idea," said Jordan. He busied himself with charts and calculations. Gradually his flying fingers slowed. His head bent low over his work. At last he stopped and folded his arms. "Where?" asked Docchi.