Daneel said, "Excuse me, Madam Gladia, for interrupting. May I have your permission to attempt an explanation of the overseer's behavior?"
D.G. said sardonically, "It comes to that, I suppose. Only a robot can explain a robot."
"Sir," said Daneel, "unless we understand the overseer, we might not be able to take effective measures in the future against the Solarian danger. I believe I have a way of accounting for her behavior."
"Go ahead," said D.G.
"The overseer," said Daneel, "did not take instant measures against us. She stood and watched us, for a while, apparently uncertain as to how to proceed. When you, Captain, approached and addressed her, she announced that you were not human and attacked you instantly. When I intervened and cried out that she was a robot, she announced that I was not human and attacked me at once, too. When Lady Gladia came forward, however, shouting at her, the overseer recognized her as human and, for a while, allowed herself to be dominated."
"Yes, I remember all that, Daneel. But what does it mean?"
"It seems to me, Captain, that it is possible to alter a robot's behavior fundamentally without ever touching the Three Laws, provided, for instance, that you alter the definition of a human being. A human being, after all, is only what it is defined to be."
"Is that so? What do you consider a human being to be?"
Daneel was not concerned with the presence or absence of sarcasm. He said, "I was constructed with a detailed description of the appearance and behavior of human beings, Captain. Anything that fits that description is a human being to me. Thus, you have the appearance and the behavior, while the overseer had the appearance but not the behavior.
"To the overseer, on the other hand, the key property of a human being was speech, Captain. The Solarian accent is a distinctive one and to the overseer something that looked like a human being was defined as a human being only if it spoke like a Solarian. Apparently, anything that looked like a human being but did not speak with a Solarian accent was to be destroyed without hesitation. As was any ship carrying such beings."
D.G. said thoughtfully, "You may be right."
"You have a Settler accent, Captain, as distinctive in its way, as the Solarian accent is, but the two are widely different. As soon as you spoke, you defined yourself as nonhuman to the overseer, who announced that and attacked."
"And you speak with an Auroran accent and were likewise attacked."
"Yes, Captain, but Lady Gladia spoke with an authentic Solarian accent and so she was recognized as human."
D.G. considered the matter silently for a while, then said, "That's a dangerous arrangement, even for those who would make use of it. If a Solarian, for any reason, at any time addressed such a robot in a way that the robot did not consider an authentic Solarian accent, that Solarian would be attacked at once. If I were a Solarian, I would be afraid to approach such a robot. My very effort to speak pure Solarian might very likely throw me off and get me killed."
"I agree, Captain," said Daneel, "and I would imagine that that is why those who manufacture robots do not ordinarily limit the definition of a human being, but leave it as broad as possible. The Solarians, however, have left the planet. One might suppose that the fact that overseer robots have this dangerous programming is the best indication that the Solarians have really left and are not here to encounter the danger. The Solarians, it appears, are at this moment concerned only that no one who is not a Solarian be allowed to set foot on the planet."
"Not even other Spacers?"
"I would expect, Captain, that it would be difficult to define a human being in such a way as to include the dozen of different Spacer accents and yet exclude the scores of different Settler accents. Keying the definition to the distinctive Solarian accent alone would be difficult enough."
D.G. said, "You are very intelligent, Daneel, I disapprove of robots, of course, not in themselves but as an unsettling influence on society. And yet, with a robot such as yourself at my side, as you were once at the Ancestor's - "
Gladia interrupted. "I'm afraid not, D.G. Daneel will never be a gift, nor will he ever be sold, nor can he be easily taken by force."
D.G. lifted his hand in a smiling negative. "I was merely dreaming, Lady Gladia. I assure you that the laws of Baleyworld would make my possession of a robot unthinkable."
Giskard said suddenly, "May I have your permission, Captain, to add a few words?"
D.G. said, "Ah, the robot who managed to avoid the action and who returned when all was safely over."
"I regret that matters appear to be as you have stated. May I have your permission, Captain, to add a few words, notwithstanding?"
"Well, go on."
"It would seem, Captain, that your decision to bring the Lady Gladia with you on this expedition has worked out very well. Had she been absent and had you ventured on your exploratory mission with only members of the ship's crew as companions, you would all have been quickly killed and the ship destroyed. It was only Lady Gladia's ability to speak like a Solarian and her courage in facing the overseer that changed the outcome."
"Not so," said D.G., "for we would all have been destroyed, possibly even Lady Gladia, but for the fortuitous event that the overseer spontaneously inactivated."
"It was not fortuitous, Captain," said Giskard, "and it is extremely unlikely that any robot will inactivate spontaneously. There has to be a reason for inactivation and I can suggest one possibility. Lady Gladia ordered the robot to stop on several occasions, as friend Daneel has told me, but the instructions under which the overseer worked were more forceful.