RIBBON IN THE SKY BY MURRAY LEINSTER Illustrated by van Dongen [Transcriber's Note: This etext was produced from Astounding Science Fiction June 1957. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] I "An error is a denial of reality, but mistakes are mere mental malfunctionings. In an emergency, a mistake may be made because of the need for precipitate action. There is no time to choose the best course: something must be done at once. Most mistakes, however, are made without any such exterior pressure. One accepts the first-imagined solution to a problem without examining it, either out of an urgent desire to avoid the labor of thinking, or out of impassioned reluctance to think about the matter at hand when prettier and more pleasurable other things can be contemplated...." _The Practice of Thinking_ Fitzgerald It turned out afterward that somebody had punched the wrong button in a computer. It was in a matter in which mistakes are not permissible, but just as nothing can be manufactured without an ordinary hammer figuring somewhere in the making or the making-ready-to-make, so nothing can be done without a fallible human operating at some stage of the proceedings. And humans make mistakes casually, off-handedly, with impartial lack of malice, and unpredictability. So.... Calhoun heard the tape-speaker say, "_When the gong sounds, breakout will follow in five seconds._" Then it made solemn ticking noises while Calhoun yawned and put aside the book, "The Practice of Thinking," that he'd been studying. Study was a necessity in his profession. Besides, it helped to pass the time in overdrive. He went to the control-desk chair and strapped in. Murgatroyd the _tormal_ uncoiled his tail from about his nose and stood up from where he was catching twenty winks. He padded to the place under Calhoun's chair where there were things to grab hold of, if necessary, with four black paws and a prehensile tail. "_Chee_," said Murgatroyd conversationally in his shrill treble. "I agree," Calhoun told him gravely. "Stone walls do not a prison make, nor Med Ship hulls a cage. But it will be good to get outside for a change." The tape-speaker ticked and tocked and ticked and tocked. There was the sound of a gong. A voice said measuredly, "_Five--four--three--two--one--_"