“That is so. Jander was a humaniform robot like myself.”

“Might it not be, then, that no case of roboticide was intended?”

“I do not understand, Partner Elijah.”

Baley said, a little impatiently, “Might not the killer have thought this Jander was a human being, that the intention was homicide, not roboticide?”

Slowly, Daneel shook his head. “Humaniform robots are quite like human beings in appearance, Partner Elijah, down to the hairs and pores in our skin. Our voices are thoroughly natural, we can go through the motions of eating, and so on. And yet, in our behavior there are noticeable differences. There may be fewer such differences with time and with refinement of technique,—but as yet they are many. You—and other Earthmen not used to humaniform robots—may not easily notes these differences, but Aurorans would. No Auroran would mistake Jander—or me—for a human being, not for a moment.”

“Might some Spacer, other than an Auroran, make the mistake?”

Daneel hesitated. “I do not think so. I do not speak from personal observation or from direct programmed knowledge, but I do have the programming to know that all Spacer worlds are as intimately acquainted with robots as Aurora is—some, like Solaria, even more so—and I deduce, therefore, that no Spacer would miss the distinction between human and robot.”

“Are there humaniform robots on the other Spacer worlds?”

“No, Partner Elijah, they exist only on Aurora so far.”

“Then other Spacers would not be intimately acquainted with humaniform robots and might well miss the distinctions and mistake them for human beings.”

“I do not think that is likely. Even humaniform robots will behave in robotic fashion in certain definite ways that any Spacer would recognize.”

“And yet surely there are Spacers who are not as intelligent as most, not as experienced, not as mature. There are Spacer children, if nothing else, who would miss the distinction.”

“It is quite certain, Partner Elijah, that the—roboticide was not committed by anyone unintelligent, inexperienced, or young. Completely certain.”

“We’re making eliminations. Good, If no Spacer would miss the distinction, what about an Earthman? Is it possible that—”

“Partner Elijah, when you arrive in Aurora, you will be the first Earthman to set foot on the planet since the period of original settlement was over. All Aurorans now alive were born on Aurora or, in a relatively few cases, on other Spacer worlds.

“The first Earthman,” muttered Baley. “I am honored. Might not an Earthman be present on Aurora without the knowledge of Aurorans?”

“No!” said Daneel with simple certainty.

“Your knowledge, Daneel, might not be absolute.”

“No!” came the repetition, in tones precisely similar to the first.

“We conclude, then,” said Baley with a shrug, “that the roboticide was intended to be roboticide and nothing else.”

“That was the conclusion from the start.”

Baley said, “Those Aurorans who concluded this at the start had all the information to begin with. I am getting it now for the first time.”

“My remark, Partner Elijah, was not meant in any pejorative manner. I know better than to belittle your abilities.”

“Thank you, Daneel. I know there was no intended sneer in your remark.—You said just a while ago that the roboticide was not committed by anyone unintelligent,—inexperienced, or young and that this is completely certain. Let us consider your remark—”

Baley knew that he was taking the long route. He had to. Considering his lack of understanding of Auroran ways and of their manner of thought, he could not afford to make assumptions and skip steps. If he were dealing with an intelligent human being in this way, that person would be likely to grow impatient and blurt out information—and consider Baley an idiot into the bargain. Daneel, however, as a robot, would follow Baley down the winding road with total patience.

That was one type of behavior that gave away Daneel as a robot, however humaniform he might be. An Auroran might be able to judge him a robot from a single answer to a single question. Daneel was right as to the subtle distinctions.

Baley said, “One might eliminate children, perhaps also most women, and many male adults by presuming that the method of roboticide involved great strength—that Jander’s head was perhaps crushed by a violent blow or that his chest was smashed inward. This would not, I imagine, be easy for anyone who was not a particularly large and strong human being.” From what Demachek had said on Earth, Baley knew that this was not the manner of the roboticide, but how was he to tell that Demachek herself had not been misled?

Daneel said, “It would not be possible at all for any human being.”

“Why not?”

“Surely, Partner Elijah, you are aware that the robotic skeleton is metallic in nature and much stronger than human bone. Our movements are more strongly powered, faster, and more delicately controlled. The Third Law of Robotics states: ‘A robot must protect its own existence.’ An assault by a human being could easily be fended off. The strongest human being could be immobilized. Nor is it likely that a robot can be caught unaware. We are always aware of human beings. We could not fulfill our functions otherwise.”

Baley said, “Come now, Daneel. The Third Law states: ‘A robot must protect its own existence, as long as such protection does not conflict with the First or Second Law.’ The Second Law states: ‘A robot must obey the orders given it by a human being, except where such orders would conflict with the First Law.’ And the First Law states: ‘A robot may, not injure a human being or, through inaction, allow a human being, to come to harm.’ A human being could order a robot to destroy himself—and a robot would then use his own strength to smash his own skull. And if a human being attacked a robot, that robot could not fend off the attack without harming the human being, which would violate First Law.”

Daneel Said, “You are, I suppose, thinking of Earth’s robots. On Aurora—or on any of the Spacer worlds—robots are regarded more highly than on Earth, and are, in general, more complex, versatile, and valuable. The Third Law is distinctly stronger in comparison to the Second Law on Spacer worlds than it is on Earth. An order for self-destruction would be questioned and there would have to be a truly legitimate reason for it to be carried, through—a clear and present danger. And in fending off an attack, the First Law would not be violated, for Auroran robots are deft enough to immobilize a human being without hurting him.”

“Suppose, though, that a human being maintained that, unless a robot destroyed himself, he—the human being—would be destroyed? Would not the robot then destroy himself?”

“An Auroran robot would surely question a mere statement to that effect. There would have to be clear evidence of the possible destruction of a human being.”

“Might not a human being be, sufficiently subtle to so arrange matters in such a way as to make it seem to a robot that the human being was indeed in great danger? Is it the ingenuity that would be required that makes you eliminate the unintelligent, inexperienced, and young?”

And Daneel said, “No, Partner Elijah, it is not.”

“Is there an error in my reasoning?”

“None.”

“Then the effort may be in my assumption that he was physically damaged. He was not, in actual fact, physically damaged. Is that right?”

“Yes, Partner Elijah.”

(That meant Demachek had had her facts straight, Baley thought.)

“In that case, Daneel, Jander was mentally damaged. Roblock! Total and irreversible!”

“Roblock?”

“Short for robot-block, the permanent shutdown of the functioning of the positronic pathways.”

“We do not use the word ‘roblock’ on Aurora, Partner Elijah.”

“What do you say?”