"Yes, and I'm your sounding board on that or hadn't you noticed? I'll need it for psychohistory when the time comes, so I suspect you'll be an indispensable help to me."

"Good! Now that we've settled why you stay with me-I knew it couldn't be for my ethereal beauty-let me go on to explain that occasionally, when your discussion veers away from the strictly mathematical aspects, it seems to me that I get your drift. You have, on a number of occasions, explained what you call the necessity of minimalism. I think I understand that. By it, you mean-"

"I know what I mean."

Dors looked hurt. "Less lofty, please, Hari. I'm not trying to explain to you. I want to explain it to myself. You say you're my sounding board, so act like one. Turnabout is fair play, isn't it?"

"Turnabout is fine, but if you're going to accuse me of loftiness when I say one little-"

``Enough! Shut up! You have told me that minimalism is of the highest importance in applied psychohistory; in the art of attempting to change an undesired development into a desired one or, at any rate, a toss undesired one. You have said that a change must be applied that is as minute, as minimal, as possible-"

"Yes," said Seldon eagerly, "that is because-"

"No, Hari. I'm trying to explain. We both know that you understand it. You must have minimalism because every change, any change, has a myriad of side effects that can't always be allowed for. If the change is side effects too many, then it becomes certain that the outcome will be far removed from anything you've planned and that it would be entirely unpredictable."

"Right," said Seldon. "That's the essence of a chaotic-effect. The problem is whether any change is small enough to make the consequence reasonably predictable or whether human history is inevitably and unalterably chaotic in every respect. It was that which, at the start, made me think that psychohistory was not-"