.

"You did it to yourself," Paul reminded him. "That's your own feedback
pulse just beefed up a little, remember. How did it feel?"

"Terrible! No wonder a guy dodges that. It's enough to make him wreck a
space station to avoid the full blast of it."

"What would you call it?"

"I don't know--," Holt hesitated. "Grief, maybe. Regret--anxiety. But
regret, mostly, I guess."

"That's your feedback," Paul said as he removed the terminals and turned
to the others. "These feedback pulses we've isolated are nothing but
stabs of pure emotion."

He turned with a faint smile to Holt. "You and Harper and the rest of
the iron-bowelled boys were so convinced that the pure mechanical man
would be utterly devoid of all emotional responses and content! And I
was so sure that a warm, responsive, emotional human being could never
respond like a cold machine!

"And we were both utterly wrong. The human being does both. He operates
on true cybernetic principles. But the content of his feedback control
pulses is sheer emotion!

"A small error, a stab of regret. It's repeated, magnified, or
diminished until the action gets back on the track that brings predicted
results. Ignored, the error builds up until the whole structure goes
smash.

"And we're _taught_ to ignore it! It's the noble, brave and manly thing
to ignore the human feelings that surge through us. Be steel, be glass,
be electrons--anything but a responsive, emotional human being! That's
the way to be a superman! We've tried to find the way to perfection and
have fought tooth and nail against the only means of achieving it."

Barker's face was glowing with excitement and Holt seemed to be
remembering something afar off. "That _was_ it," he breathed softly. "I
can feel it now--the way it was as I began to get jittery and make
mistakes in the test procedures. I seemed to fight something within
myself--something I thought was making me do it wrong. But it wasn't
that, at all. I was fighting against the emotional feedback the errors
were throwing at me."

"Right," said Paul. "And your iron-hard, errorless Superman is going to
be the most emotionally sensitive creature you can produce."

"How did you catch on to this?" Barker asked.

"We should have seen it in Harper. He's the original iron-man. He's
bottled up and fought his emotions all his life. A concentrated dose of
his own feedback simply shattered the dam.

"But I didn't get it until I watched Morgan's mob rea