"It's on the level," said Paul. "You were right all along."
When he returned to his office an urgent message from Barker awaited him. He hurried down to the testing laboratory, where the older man greeted him in excitement and anxiety.
"It looks like we've got something by the tail and can't let go of it. Come in and have a look."
Paul followed him and found Captain Harper in an observation room, writhing on a cot in a storm of tears and emotional fury. He beat against the walls and the floor with his fists as his sobbing continued beyond control.
"What happened to him?" Paul demanded.
"We have three others in the same condition," said Barker. "We tried to determine the effect of a pure feedback impulse, and fed it back to each of them in amplified form as we found it on their charts. This is what happened. I'm afraid we may have cost them their sanity, and we don't know why."
"How could their own feedback do such a thing to them?" he asked in wonder. "What part of the chart did you take it from?"
"We used the impulse that didn't get through, the one that was blocked so that error resulted. Apparently this is the alternative to error." He nodded toward the writhing, sobbing man. "Harper reached a point where he had to fail or else be subject to this psychic storm."
Paul ran his long, bony fingers through his hair. "This makes less sense than ever! If that's true, then we've got to take back what we've told Oglethorpe. His errorless man isn't possible, after all."
"I don't know." Barker shook his head thoughtfully. "Evidently the production of error is a protection against the admission of this intolerable feedback impulse. But the question remains: why is it intolerable, and why does it become so after numerous other feedback impulses have been passed?