Cities in Flight

longer sufficed—in fact, could seldom be called upon at all. This had had the effect of driving those participants who were primarily engineers or administrators or both, like Miramon and Amalfi, or primarily philosophers, like Gifford Bonner, into the stance of bystanders; so that the discussions now had been shifted to Retma’s study. Amalfi stuck with them whenever he could, for he never knew when Retma, Jake or Schloss might drop back out of the symbolic stratosphere and say something he could comprehend and use.

It was being heavy weather in the study today, however. Retma was saying:

“The problem as I see it is that time in our experience is not retro-dictable. We write a diffusion equation like this, for instance.” He turned to his blackboard—the immemorial “research instrument” of theoretical physicists everywhere—and wrote:

Over Retma’s head, for Jake’s benefit, a small proxy fixed its television eye on the precise chalkmarks. “In this situation a-squared is a real constant, so it is predictive only for a future time t, but not for an earlier time t, because the retrodictive expression diverges.”

“An odd situation,” Schloss agreed. “It means that in any thermodynamic situation we have better information about the future than we do about the past. In the anti-matter universe it has to be the other way around—but only from our point of view; a hypothetical observer living under their laws and composed of their energies, I assume, couldn’t tell the difference.”

“Can we write a convergent retrodictive equation?” Jake’s voice said. “One which describes what their situation is as we would see it, if we could? If we can’t, I don’t see how we can design instruments to detect any difference.”

“It can be done,” Retma said. “For instance.” He turned to the blackboard and the symbols flowed squeakily:

“Ah-ha,” Schloss said. “Thus giving us an imaginary constant in place of a real one. But your second equation isn’t a mirror of your first; parity is not conserved. Your first equation is an equalization process, but this one is oscillatory. Surely the gradient on the other side doesn’t pulsate!”

“Parity is not conserved anyhow in these weak reactions,” Jake said. “But I think the objection may be well taken all the same. If Equation Two describes anything at all, it can’t be the other side. It has to be both sides—the whole vast system, providing that it is cyclical, which we don’t know yet. Nor do I see any way to test it, it’s as ultimately and finally unprovable as the Mach Hypothesis—”

The door opened quietly and a young Hevian beckoned silently to Amalfi. He got up without too much reluctance; the boys were giving him a hard time today, and he found that he missed Estelle. It had been her function to remind the group of possible pitfalls in Retma’s notation: here, for instance, Retma was using the d which in Amalfi’s experience was an increment in calculus, as simply an expression for a constant; he was using the G which to Amalfi was the gravitational constant, to express a term in thermodynamics Amalfi was accustomed to seeing written with the greek capital letter ?; and could Schloss be sure that Retma’s i was equivalent to the square root of minus one, as it was in New Earth math? Doubtless Schloss had good reason to feel that agreement on that very simple symbol had been established between the New Earthmen and Retma long since, but without Estelle it made Amalfi feel uncomfortable. Besides, though he knew intellectually that all the important battles against a problem in physics are won in such blackboard sessions as this, he was not temperamentally fitted to them. He liked to see things happening.

They began to happen forthwith. As soon as the door was decently closed on the visible and invisible physicists, the young Hevian said:

“I am sorry to disturb you, Mr. Amalfi. But there is an urgent call for you from New Earth. It is Mayor Hazleton.”

“Helleshin!” Amalfi said. The word was Vegan; no one now alive knew what it meant. “All right, let’s go.”

“Where is my wife?” Hazleton demanded without preamble. “And my grandson, and Jake’s daughter? And where have you been these past three weeks? Why didn’t you call in? I’ve been losing my mind, and the Hevians gave me the Force Four blowaround before they’d let me through to you at all—”

“What are you talking about, Mark?” Amalfi said. “Stop sputtering long enough to let me know what this is all about.”

“That’s what I want to know. All right. I’ll begin again. Where is Dee?”

“I don’t know,” Amalfi said patiently. “I sent her home three weeks ago. If you can’t find her, that’s your problem.”

“She never got here.”

“She didn’t? But—”

“Yes, but. That recall ship never landed. We never heard from it at all. It just vanished, Dee, children and all. I’ve been phoning you frantically to find out whether or not you ever sent it; now I know that you did. Well, we know what that means. You’d better give up dabbling in physics, Amalfi, and get back here on the double.”

“What can I do?” Amalfi said. “I don’t know any more about it than you do.”

“You can damn well come back here and help me out of this mess.”

“What mess?”

“What have you been doing the past three weeks?” Hazleton yelled. “Do you mean to tell me that you haven’t heard what’s been happening?”

“No,” Amalfi said. “And stop yelling. What did you mean, ‘We know what that means’? If you think you know what’s happened, why aren’t you doing something about it, instead of jamming the Dirac raising me? You’re the mayor; I’ve got work of my own to do.”

“I’ll be the mayor about two days longer, if my luck holds,” Hazleton said in a savage voice. “And you’re directly responsible, so you needn’t bother trying to duck. Jorn the Apostle began to move two weeks ago. He has a navy now, though where he raised it is beyond me. His main body’s nowhere near New Earth, but he’s about to take New Earth all the same—the whole planet is swarming with farm kids with fanatical expressions and dismounted spindillies. As soon as they get to me, I’m going to surrender out of hand—you know as well as I do what one of those machines can do, and the farmers are using them as side-arms. I’m not going to sacrifice tens of thousands of lives just to maintain my administration; if they want me out, they can have me out.”

“And this is my fault? I once told you the Warriors of God were dangerous.”

“And I didn’t listen. All right. But they’d never have moved if it hadn’t been for the fact that you and Miramon didn’t censor what you’re up to. It’s given Jorn his cause; he’s telling his followers that you’re meddling with the pre-ordained Armageddon and jeopardizing their chances of salvation. He’s proclaimed a jehad against the Hevians for instigating it, and the jehad includes New Earth because we’re working with the Hevians—”

Over the phone came four loud, heavy strokes of fist upon metal.

“Gods of all stars, they’re here already,” Hazleton said. “I’ll leave the line open as long as I can—maybe they won’t notice ….” His voice faded. Amalfi hung on grimly, straining to hear every sound.

“Sinner Hazleton,” a young and desperately frightened voice said, almost at once, “you have been found out. By the Word of Jorn, you—you are ordered to corrective discipline. Are you gone-tuh—will you submit humbly?”

“If you fire that thing in here,” Hazleton’s voice said, quite loudly—he was obviously projecting for the benefit of the mike—“you’ll uproot half the city. What good will that do you?”

“We will die in the Warriors,” the other voice said. It was still tense, but now that it spoke of dying it seemed more self-assured. “You will go to the flames.”

“And all the other people—?”

“Sinner Hazleton, we do not threaten,” a deeper, older voice said. “We think there is some good in everyone. Jorn commands us to redeem, and that we will do. We have hostages for your good conduct.”

“Where are they?”

“They were picked up by the Warriors of God,” the deep voice said. “Jorn in his blessedness was kind enough to grant us a cordon sanitaire for this Godless world. Will you yield, for the salvation of this woman and these two helpless children? I advise you, Sinner—hey, what the hell, that phone’s open! Jody, smash that switch, and fast! What did I ever do to be saddled with a cadre of lousy yokels—”

The speaker began a thin howl and went dead before the cry was properly born.