"It's in progress," said the mathematician, without interest.
She stared at him angrily for a moment, then turned to Kallner. "Nester 10 is decidedly aware of what we're doing, general. He had no reason to jump for the bait in this experiment, especially after the first time, when he must have seen that there was no real danger to our subject. The others couldn't help it; but he was deliberately falsifying a reaction."
"What do you think we ought to do now, then, Dr. Calvin?"
"Make it impossible for him to fake an action the next time. We will repeat the experiment, but with an addition. High-tension cables, capable of electrocuting the Nestor models will be placed between subject and robot - enough of them to avoid the possibility of jumping over - and the robot will be made perfectly aware in advance that touching the cables will mean death."
"Hold on," spat out Bogert with sudden viciousness. "I rule that out. We are not electrocuting two million dollars worth of robots to locate Nestor 10. There are other ways."
"You're certain? You've found none. In any case, it's not a question of electrocution. We can arrange a relay which will break the current at the instant of application of weight. If the robot should place his weight on it, he won't die. But he won't know that, you see."
The general's eyes gleamed into hope. "Will that work?"
"It should. Under those conditions, Nestor 10 would have to remain in his seat. He could be ordered to touch the cables and die, for the Second Law of obedience is superior to the Third Law of self-preservation. But he won't be ordered to; he will merely be left to his own devices, as will all the robots. In the case of the normal robots, the First Law of human safety will drive them to their death even without orders. But not our Nestor 10. Without the entire First Law, and without having received any orders on the matter, the Third Law, self-preservation, will be the highest operating, and he will have no choice but to remain in his seat. It would be a forced action."
"Will it be done tonight, then?"
"Tonight," said the psychologist, "if the cables can be laid in time. I'll tell the robots now what they're to be up against."
A man sat in the chair, motionless, silent. A weight dropped, crashed downward, then pounded aside at the last moment under the synchronized thump of a sudden force beam.
Only once-
And from her small camp chair in the observing booth in the balcony, Dr. Susan Calvin rose with a short gasp of pure horror.
Sixty-three robots sat quietly in their chairs, staring owlishly at the endangered man before them. Not one moved.
Dr. Calvin was angry, angry almost past endurance. Angry the worse for not daring to show it to the robots that, one by one were entering the room and then leaving. She checked the list. Number twenty-eight was due in now - Thirty-five still lay ahead of her.
Number Twenty-eight entered, diffidently.
She forced herself into reasonable calm. "And who are you?"
The robot replied in a low, uncertain voice, "I have received no number of my own yet, ma'am. I'm an NS-2 robot, and I was Number Twenty-eight in line outside. I have a slip of paper here that I'm to give to you."
"You haven't been in here before this today?"
"No, ma'am."
"Sit down. Right there. I want to ask you some questions, Number Twenty-eight. Were you in the Radiation Room of Building Two about four hours ago?"
The robot had trouble answering. Then it came out hoarsely, like machinery needing oil, "Yes, ma'am."
"There was a man who almost came to harm there, wasn't there?"
"Yes, ma'am."
"You did nothing, did you?"
"No, ma'am."
"The man might have been hurt because of your inaction. Do you know that?"
"Yes, ma'am. I couldn't help it, ma'am." It is hard to picture a large expressionless metallic figure cringing, but it managed.
"I want you to tell me exactly why you did nothing to save him."
"I want to explain, ma'am. I certainly don't want to have you... have anyone... think that I could do a thing that might cause harm to a master. Oh, no, that would be a horrible... an inconceivable-"
"Please don't get excited, boy. I'm not blaming you for anything. I only want to know what you were thinking at the time."
"Ma'am, before it all happened you told us that one of the masters would be in danger of harm from that weight that keeps falling and that we would have to cross electric cables if we were to try to save him. Well, ma'am, that wouldn't stop me. What is my destruction compared to the safety of a master? But... but it occurred to me that if I died on my way to him, I wouldn't be able to save him anyway. The weight would crush him and then I would be dead for no purpose and perhaps some day some other master might come to harm who wouldn't have, if I had only stayed alive. Do you understand me, ma'am?"
"You mean that it was merely a choice of the man dying, or both the man and yourself dying. Is that right?"
"Yes, ma'am. It was impossible to save the master. He might be considered dead. In that case, it is inconceivable that I destroy myself for nothing - without orders."
The robopsychologist twiddled a pencil. She had heard the same story with insignificant verbal variations twenty-seven times before. This was the crucial question now.
"Boy," she said, "your thinking has its points, but it is not the sort of thing I thought you might think. Did you think of this yourself?"
The robot hesitated. "No."
"Who thought of it, then?"
"We were talking last night, and one of us got that idea and it sounded reasonable."