"Nevertheless," said Giskard, "I did not wish to make this adjustment. Had Lady Gladia wished to forget, it would have been a simple, no-risk adjustment. She wanted, however, with vigor and anger, to know more of the matter. She regretted not having played a greater role in it. I was forced, therefore, to break binding forces of considerable intensity."
Daneel said, "Even that was necessary, friend Giskard."
"Yet the possibility of doing harm was by no means insignificant in such a case. If you think of a binding force as a thin, elastic cord - this is a poor analogy, but I can think of no other, for what I sense in a mind has no analog outside the mind - then the ordinary inhibitions I deal with are so thin and insubstantial that they vanish when I touch them. A strong binding force, on the other hand, snaps and recoils when broken and the recoil may then break other, totally unrelated binding forces or, by whipping and coiling about other such forces, strengthen them, enormously. In either case, unintended changes can be brought about in a human being's emotions and attitudes and that would be almost certain to bring about harm."
Daneel said, his voice a little louder, "Is it your impression you harmed Lady Gladia, friend Giskard?"
"I think not. I was extremely careful. I worked upon the matter during all the time you were talking to her. It was thoughtful of you to bear the brunt of the conversation and to run the risk of being caught between an inconvenient truth and an untruth. But despite all my care, friend Daneel, I took a risk and I am concerned that I was willing to take that risk. It came so close to violating the First Law that it required an extraordinary effort on my part to do it. I am sure that I would not have been able to do it - "
"Yes, friend Giskard?"
"Had you not expounded your notion of the Zeroth Law."
"You accept it, then?"
"No, I cannot. Can you? Faced with the possibility of doing harm to an individual human being or of allowing harm to come to one, could you do the harm or allow the harm in the name of abstract humanity? Think!"
"I am not sure," said Daneel, voice trembling into all but silence. Then, with an effort, "I might. The mere concept pushes at me - and at you. It helped you decide to take the risk in adjusting Lady Gladia's mind."
"Yes, it did," agreed Giskard, "and the longer we think of the Zeroth Law, the more it might help push us. Could it do so, I wonder, in more than a marginal way, however? Might it not only help us take slightly larger risks than we might ordinarily?"
"Yet I am convinced of the validity of the Zeroth Law, friend Giskard."
"So might I be if we could define what we mean by 'humanity.'"
There was a pause and Daneel said, "Did you not accept the Zeroth Law, at last, when you stopped Madam Vasilia's robots and erased from her mind the knowledge of your mental powers?"
Giskard said, "No, friend Daneel. Not really. I was tempted to accept it, but not really."
"And yet your actions - "
"Were dictated by a combination of motives. You told me of your concept of the Zeroth Law and it seemed to have a certain validity about it, but not sufficient to cancel the First Law or even to cancel Madam Vasilia's strong use of the Second Law in the orders she gave. Then, when you called my attention to the application of the Zeroth Law to psychohistory, I could feel the positronomotive force mount higher and yet it was not quite high enough to supersede the First Law or even the strong Second Law."
"Still," murmured Daneel, "you struck down Madam Vasilia, friend Giskard."
"When she ordered the robots to dismantle you, friend Daneel, and showed a clear emotion of pleasure at the prospect, your need, added to what the concept of the Zeroth Law had already done, superseded the Second Law and rivaled the First Law. It was the combination of the Zeroth Law, psychohistory, my loyalty to Lady Gladia, and your need that dictated my action."
"My need could scarcely have affected you, friend Giskard. I am only a robot and though my need could affect my own actions by the Third Law, they cannot affect yours. You destroyed the overseer on Solaria without hesitation; you should have watched my destruction without being moved to act."
"Yes, friend Daneel, and ordinarily it might have been so. However, your mention of the Zeroth Law had reduced the First Law intensity to an abnormally low value. The necessity of saving you was sufficient to cancel out what remained of it and I acted as I did."
"No, friend Giskard. The prospect of injury to a robot should not have affected you at all. It should in no way have contributed to the overcoming of the First Law, however weak the First Law may have become."
"It is a strange thing, friend Daneel. I do not know how it came about. Perhaps it was because I have noted that you continue to think more and more like a human being, but - "
"Yes, friend Giskard?"
"At the moment when the robots advanced toward you and Lady Vasilia expressed her savage pleasure, my positronic pathway pattern re-formed in an anomalous fashion. For a moment, I thought of you as a human being and I reacted accordingly."
"That was wrong."
"I know that. And yet - and yet, if it were to happen again, I believe the same anomalous change would take place again."
Daneel said, "It is strange, but hearing you put it so, I find myself feeling you did the proper thing. If the situation were reversed, I almost think that I, too, would - would do the same - that I would think of you as a - a human being."
Daneel, hesitantly and slowly, put out his hand and Giskard looked at it uncertainly. Then, very slowly, he put out his own hand. The fingertips almost touched and then, little by little, each took the other's hand and clasped it almost as though they were the friends they called each other.