" 'Three. A robot must protect its own existence, as long as such protection does not conflict with the First or Second Law.'
"But I had a... a friend twenty thousand years ago. Another robot. Not like myself. He could not be mistaken for a human being, but it was he who had the mental powers and it was through him that I gained mine. "It seemed to him that there should be a still more general rule than any of the Three Laws. He called it the Zeroth Law, since zero comes before one. It is:
" 'Zero. A robot may not injure humanity or, through inaction, allow humanity to come to harm.'
"Then the First Law must read:
" 'One. A robot may not injure a human being or, through inaction, allow a human being to come to harm, except where that would conflict with the Zeroth Law.'
"And the other laws must be similarly modified. Do you understand?"
Daneel paused earnestly and Seldon said, "I understand." Daneel went on. "The trouble is, Hari, that a human being is easy to identify. I can point to one. It is easy to see what will harm a human being and what won't-relatively easy, at least. But what is humanity? To what can we point when we speak of humanity? And how can we define harm to humanity? When will a course of action do more good than harm to humanity as a whole and how can one tell? The robot who first advanced the Zeroth law died-became permanently inactive-because he was forced into an action that he felt would save humanity, yet which he could not be sure would save humanity. And as he became inactivated, he left the care of the Galaxy to me.
"Since then, I have tried. I have interfered as little as possible, relying on human beings themselves to judge what was for the good. They could gamble; I could not. They could miss their goals; I did not dare. They could do harm unwittingly; I would grow inactive if I did. The Zeroth Law makes no allowance for unwitting harm.
"But at times I am forced to take action. That I am still functioning shows that my actions have been moderate and discreet. However, as the Empire began to fail and to decline, I have had to interfere more frequently and for decades now I have had to play the role of Demerzel, trying to run the government in such a way as to stave off ruin-and yet I will function, you see.
"When you made your speech to the Decennial Convention, I realized at once that in psychohistory there was a tool that might make it possible to identify what was good and bad for humanity. With it, the decisions we would make would be less blind. I would even trust to human beings to make those decisions and again reserve myself only for the greatest emergencies. So I arranged quickly to have Cleon learn of your speech and call you in. Then, when I heard your denial of the worth of psychohistory, I was forced to think of some way to make you try anyway. Do you understand, Hari?"
More than a little daunted, Seldon said, "I understand, Hummin."
"To you, I must remain Hummin on those rare occasions when I will be able to see you. I will give you what information I have if it is something you need and in my persona as Demerzel I will protect you as much as I can. As Daneel, you must never speak of me."
"I wouldn't want to," said Seldon hurriedly. "Since I need your help, it would ruin matters to have your plans impeded."
"Yes, I know you wouldn't want to." Daneel smiled wearily. "After all, you are vain enough to want full credit for psychohistory. You would not want anyone to know-ever-that you needed the help of a robot."
Seldon flushed. "I am not-"
"But you are, even if you carefully hide it from yourself. And it is important, for I am strengthening that emotion within you minimally so that you will never be able to speak of me to others. It will not even occur to you that you might do so."
Seldon said, "I suspect Dors knows-"
"She knows of me. And she too cannot speak of me to others. Now that you both know of my nature, you can speak of me to each other freely, but not to anyone else."
Daneel rose.-Hari, I have my work to do now. Before long, you and Dors will be taken back to the Imperial Sector-"
"The boy Raych must come with me. I cannot abandon him. And there is a young Dahlite named Yugo Amaryl-"
"I understand. Raych will be taken too and you can do with any friend as you will. You will all be taken care of appropriately. And you will work on psychohistory. You will have a staff. You will have the necessary computers and reference material. I will interfere as little as possible and if there is resistance to your views that does not actually reach the point of endangering the mission, then you will have to deal with it yourself."
"Wait, Hummin," said Seldon urgently. "What if, despite all your help and all my endeavors, it turns out that psychohistory cannot be made into a practical device after all? What if I fail?"
Daneel rose. "In that case, I have a second plan in hand. One I have been working on a long time on a separate world in a separate way. It too is very difficult and to some ways even more radical than psychohistory. It may fail too, but there is a greater chance of success if two roads are open than if either one alone was.
"Take my advice, Hari! If the time comes when you are able to set up some device that may act to prevent the worst from happening see if you can think of two devices, so that if one fails, the other will carry on. The Empire must be steadied or rebuilt on a new foundation. Let there be two such, rather than one, if that is possible."
He rose, "Now I must return to my ordinary work and you must turn to yours. You will be taken care of."
With one final nod, he rose and left.
Seldon looked after him and said softly, "First I must speak to Dors."