"I know, but you're not letting me make my point. Whether any change would be small enough is not the issue. The point is that any change greater than the minimal is chaotic. The required minimum may be zero, but if it is not zero, then it is still very small-and it would be a major problem to find some change that is small enough and yet is significantly greater than zero. Now, that, I gather, is what you mean by the necessity of minimalism."

"More or less," said Seldon. "Of course, as always, the matter is expressed more compactly and more rigorously in the language of mathematics. See here-"

"Save me," said Dors. "Since you know this about psychohistory, Hari, you ought to know it about Demerzel, too. You have the knowledge but not the understanding, because it apparently doesn't occur to you to apply the rules of psychohistory to the Laws of Robotics."

To which Seldon replied faintly, "Now I don't see what you're getting at.

"He requires minimality, too, doesn't he, Hari? By the First Law of Robotics, a robot can't harm a human being. That is the prime rule for the usual robot, but Demerzel is something quite unusual and for him, the Zeroth Law is a reality and it takes precedence even over the First Law. The Zeroth Law states that a robot can't harm humanity as a whole. But that puts Demerzel into the same bind in which you exist when you labor at psychohistory. Do you see?"

"I'm beginning to."

"I hope so. If Demerzel has the ability to change minds, he has to do so without bringing about side effects he does not wish-and since he is the Emperor's First Minister, the side effects he must worry about are numerous, indeed."