There was a crawling uncertainty inside Harlan, an irresolution that was consuming him. He had the blaster in his hand. It was aimed at Noys.

But why did she say nothing? Why did she persist in this impassive attitude?

How could he kill her?

How could he not kill her?

He said hoarsely, "Well?"

She moved, but it was only to clasp her hands loosely in her lap, to look more relaxed, more aloof. When she spoke her voice seemed scarcely that of a human being. Facing the muzzle of a blaster, it yet gained assurance and took on an almost mystic quality of impersonal strength.

She said, "You cannot wish to kill me only in order to protect Eternity. If that were your desire, you could stun me, tie me firmly, pin me within this cave and then take to your travels in the dawn. Or you might have asked Computer Twissell to keep me in solitary confinement during your absence in the Primitive. Or you might take me with you at dawn, lose me in the wastes. If it is only killing that will satisfy you, it is only because you think that I have betrayed you, that I have tricked you into love first in order that I might trick you into treason later. This is murder out of wounded pride and not at all the just retribution you tell yourself it is."

Harlan squirmed. "Are you from the Hidden Centuries? Tell me."

Noys said, "I am. Will you now blast?"

Harlan's finger trembled on the blaster's contact point. Yet he hesitated. Something irrational within him could still plead her case and point up the remnants of his own futile love and longing. Was she desperate at his rejection of her? Was she deliberately courting death by lying? Was she indulging in foolish heroics born of despair at his doubts of her?

No!_

The book-films of the sickly-sweet literary traditions of the 289th might have it so, but not a girl like Noys. She was not one to meet her death at the hands of a false lover with the joyful masochism of a broken, bleeding lily.

Then was she scornfully denying his ability to kill her for any reason whatever? Was she confidently relying on the attraction she knew she had for him even now, certain that it would immobilize him, freeze him in weakness and shame.

That hit too closely. His finger clamped a bit harder on the contact.

Noys spoke again. "You're waiting. Does that mean you expect me to enter a brief for the defense?"

"What defense?" Harlan tried to make that scornful, yet he welcomed the diversion. It could postpone the moment when he must look down upon her blasted body, upon whatever remnants of bloody flesh might remain, and know that what had been done to his beautiful Noys had been done by his own hand.

He found excuses for his delay. He thought feverishly: Let her talk. Let her tell what she can about the Hidden Centuries. So much better protection for Eternity.

It put a front of firm policy on his action and for the moment he could look at her with as calm a face, almost, as she looked at him.

Noys might have read his mind. She said, "Do you want to know about the Hidden Centuries? If that will be a defense, it is easily done. Would you like to know, for instance, why Earth is empty of mankind after the 150,000th? Would you be interested?"

Harlan wasn't going to plead for knowledge, nor was he going to buy knowledge. He had the blaster. He was very intent on no show of weakness.

He said, "Talk!" and flushed at the little smile which was her first response to his exclamation.

She said, "At a moment in physiotime before Eternity had reached very far upwhen, before it had reached even the 10,000th, we of our Century-and you're right, it was the 111,394th-learned of Eternity's existence. We, toe, had Time-travel, you see, but it was based on a completely different set of postulates than yours, and we preferred to view Time, rather than shifting mass. Furthermore, we dealt with our past only, our downwhen.

"We discovered Eternity indirectly. First, we developed the calculus of Realities and tested our own Reality through it. We were amazed to find we lived in a Reality of rather low probability. It was a serious question. Why such an improbable Reality?... You seem abstracted, Andrew! Are you interested at all?"

Harlan heard her say his name with all the intimate tenderness she had used in weeks past. It should grate on him now, anger him with its cynical faithlessness. And yet it didn't.

He said desperately, "Go on and get it over with, woman."

He tried to balance the warmth of her "Andrew" with the chill anger of his "woman" and yet she only smiled again, pallidly.

She said, "We searched back through time and came across the growing Eternity. It seemed obvious to us almost at once that there had been at one point in physiotime (a conception we have also, but under another name) another Reality. The other Reality, the one of maximum probability we call the Basic State. The Basic State had encompassed us once, or had encompassed our analogues, at least. At the time we could not say what the nature of the Basic State was. We could not possibly know.

"We did know, however, that some Change initiated by Eternity in the far downwhen had managed, through the workings of statistical chance, to alter the Basic State all the way up to our Century and beyond. We set about determining the nature of the Basic State, intending to undo the evil, if evil it was. First we set up the quarantined area you call the Hidden Centuries, isolating the Eternals on the downwhen side of the 70,000th. This armor of isolation would affect us from all but a vanishingly small percentage of the Changes being made. It wasn't absolute security but it gave us time.

"We next did something our culture and ethics did not ordinarily allow us to do. We investigated our own future, our upwhen. We learned the destiny of man in the Reality that actually existed in order that we might compare it eventually with Basic State. Somewhere past the 125,000th, mankind solved the secret of the interstellar drive. They learned how to manage the Jump through hyperspace. Finally, mankind could reach the stars."

Harlan was listening in growing absorption to her measured words. How much truth was there in all this? How much was a calculated attempt to deceive him? He tried to break the spell by speaking, by breaking the smooth flow of her sentences. He said:

"And once they could reach the stars, they did so and left the Earth. Some of us have guessed that."

"Then some of you have guessed wrong. Man tried to leave Earth. Unfortunately, however, we are not alone in the Galaxy. There are other stars with other planets, you know. There are even other intelligences. None, in this Galaxy at least, are as ancient as mankind, but in the 125,000 Centuries man remained on Earth, younger minds caught up and passed us, developed the interstellar drive, and colonized the Galaxy.

"When we moved out into space, the signs were up. _Occupied! No Trespassing! Clear Out!_ Mankind drew back its exploratory feelers, remained at home. But now he knew Earth for what it was: a prison surrounded by an infinity of freedom... And mankind died out!"

Harlan said, "Just died out. Nonsense."

"They didn't just die out. It took thousands of Centuries. There were ups and downs but, on the whole, there was a loss of purpose, a sense of futility, a feeling of hopelessness that could not be overcome. Eventually there was one last decline of the birth rate and finally, extinction. Your Eternity did that."

Harlan could defend Eternity now, the more intensely and extravagantly for having so shortly before attacked it so keenly. He said, "Let us at the Hidden Centuries and we will correct that. We have not failed yet to achieve the greatest good in those Centuries we could reach."

"The greatest good?" asked Noys in a detached tone that seemed to make a mockery of the phrase. "What is that? Your machines tell you. Your Computaplexes. But who adjusts the machines and tells them what to weigh in the balance? The machines do not solve problems with greater insight than men do, only faster. Only faster! Then what is it the Eternals consider good? I'll tell you. Safety and security. Moderation. Nothing in excess. No risks without overwhelming certainty of an adequate return."

Harlan swallowed. With sudden force he remembered Twissell's words in the kettle while talking about the evolved men of the Hidden Centuries. He said: "_We bred out the unusual_."

And wasn't it so?

"Well," said Noys, "you seem to be thinking. Think of this, then. In the Reality that now exists, why is it that man is continually attempting space-travel and continually failing? Surely each space-travel era must know of previous failures. Why try again, then?"

Harlan said, "I haven't studied the matter." But he thought uneasily of the colonies on Mars, established again and again, always failing. He thought of the odd attraction that space-flight always had, even for Eternals. He could hear Sociologist Kantor Voy of the 2456th, sighing at the loss of electro-gravitic space-flight in one Century, and saying longingly: "_It had been very beautiful_." And Life-Plotter Neron Feruque, who had sworn bitterly at its passing and had launched into a fit of railing at Eternity's handling of anti-cancer serums to case his spirit.

Was there such a thing as an instinctive yearning on the part of intelligent beings to expand outward, to reach the stars, to leave the prison of gravity behind? Was it that which forced man to develop interplanetary travel dozens of times, forced him to travel over and over again to the dead worlds of a solar system in which only Earth was livable? Was it the eventual failure, the knowledge that one must return to the home prison, that brought about the maladjustments that Eternity was forever fighting. Harlan thought of the drug addiction in those same futile Centuries of the electro-gravitics.

Noys said, "In ironing out the disasters of Reality, Eternity rules out the triumphs as well. It is in meeting the great tests that mankind can most successfully rise to great heights. Out of danger and restless insecurity comes the force that pushes mankind to newer and loftier conquests. Can you understand that? Can you understand that in averting the pitfalls and miseries that beset man, Eternity prevents men from finding their own bitter and better solutions, the real solutions that come from conquering difficulty, not avoiding it."

Harlan began woodenly, "The greatest good of the greatest number--"

Noys cut in. "Suppose Eternity had never been established?"

"Well?"

"I'll tell you what would have happened. The energies that went into temporal engineering would have gone into nucleonics instead. Eternity would not have come but the interstellar drive would. Man would have reached the stars more than a hundred thousand Centuries before he did in this current Reality. The stars would then have been untenanted and mankind would have established itself throughout the Galaxy. We would have been first."

"And what would have been gained?" asked Harlan doggedly. "Would we be happier?"

"Whom do you mean by 'we'? Man would not be a world but a million worlds, a billion worlds. We would have the infinite in our grasp. Each world would have its own stretch of the Centuries, each its own values, a chance to seek happiness after ways of its own in an environment of its own. There are many happinesses, many goods, infinite variety... That is the Basic State of mankind."

"You're guessing," said Harlan, and he was angry at himself for feeling attraction for the picture she had conjured. "How can you tell what would have happened?"

Noys said, "You smile at the ignorance of the Timers who know only one Reality. We smile at the ignorance of the Eternals who think there are many Realities but that only one exists at a time."

"What does that gibberish mean?"

"We don't calculate alternate Realities. We view them. We see them in their state of non-Reality."

"A kind of ghostly never-never land where the might-have-beens play with the ifs."

"Without the sarcasm, yes."

"And how do you do that?"

Noys paused, then said, "How can I explain that, Andrew? I have been educated to know certain things without really understanding all about them, just as you have. Can you explain the workings of a Computaplex? Yet you know it exists and works."

Harlan flushed. "Well, then?"

Noys said, "We learned to view Realities and we found Basic State to be as I have described. We found, too, the Change that had destroyed Basic State. It was not any Change that Eternity had initiated; it was the establishment of Eternity itself-the mere fact of its existence. Any system like Eternity, which allows men to choose their own future, will end by choosing safety and mediocrity, and in such a Reality the stars are out of reach. The mere existence of Eternity at once wiped out the Galactic Empire. To restore it, Eternity must be done away with.

"The number of Realities is infinite. The number of any subclass of Realities is also infinite. For instance, the number of Realities containing Eternity is infinite; the number in which Eternity does not exist is infinite; the number in which Eternity does exist but is abolished is also infinite. But my people chose from among the infinite a group that involved me.

"I had nothing to do with that. They educated me for my job as Twissell and yourself educated Cooper for his job. But the number of Realities in which I was the agent in destroying Eternity was also infinite. I was offered a choice among five Realities that seemed least complex. I chose this one, the one involving you, the only Reality system involving you."

Harlan said, "Why did you choose it?"

Noys looked away. "Because I loved you, you see. I loved you long before I met you."

Harlan was shaken. She said it with such depths of sincerity. He thought, sickly: She's an actress- He said, "That's rather ridiculous."

"Is it? I studied the Realities at my disposal. I studied the Reality in which I went back to the 482nd, met first Finge, then you. The one in which you came to me and loved me, in which you took me into Eternity and the far upwhen of my own Century, in which you misdirected Cooper, and in which you and I, together, returned to the Primitive. We lived in the Primitive for the rest of our days. I saw our lives together and they were happy and I loved you. So it's not ridiculous at all. I chose this alternative so that our love might be true."

Harlan said, "All this is false. It's false. How can you expect me to believe you?" He stopped, then said suddenly, "Wait! You say you knew all this in advance? All that would happen?"

"Yes."

"Then you're obviously lying. You would have known that I would have you here at blaster point. You would have known you would fail. What is your answer to that?"

She sighed lightly, "I told you there are an infinite number of any subclass of Realities. No matter how finely we focus on a given Reality it always represents an infinite number of very similar Realities. There are fuzzy spots. The finer we focus, the less fuzzy, but perfect sharpness cannot be obtained. The less fuzzy, the lower the probability of chance variation spoiling the result, but the probability is never absolutely zero. One fuzzy spot spoiled things."

"Which?"

"You were to have come back to the far upwhen after the barrier at the 100,000th had been lowered and you did. But you were to have come back alone. It is for that reason that I was momentarily so startled at seeing Computer TwisseIl with you."

Again Harlan was troubled. How she made things fit in!

Noys said, "I would have been even more startled, had I realized the significance of that alteration in full. Had you come alone, you would have brought me back to the Primitive as you did. Then, for love of humanity, for love of me, you would have left Cooper untouched. Your circle would have been broken, Eternity ended, our life together here safe.

"But you came with Twissell, a chance variation. While coming, he talked to you of his thoughts about the Hidden Centuries and started you on a train of deductions that ended with your doubting my good faith. It ended with a blaster between us... And now, Andrew, that's the story. You may blast me. There is nothing to stop you."

Harlan's hand ached from its spastic grasp on the blaster. He shifted it dizzily to the other hand. Was there no flaw in her story? Where was the resolution he was to have gained from knowing certainly that she was a creature of the Hidden Centuries. He was more than ever tearing at himself in conflict and dawn was approaching.

He said, "Why two efforts to end Eternity? Why couldn't Eternity have ended once and for all when I sent Cooper back to the 20th?" Things would have ended then and there would not have been this agony of uncertainty."

"Because," said Noys, "ending this Eternity is not enough. We must reduce the probability of establishing any form of Eternity to as near zero as we can manage. So there is one thing we must do here in the Primitive. A small Change, a little thing. You know what a Minimum Necessary Change is like. It is only a letter to a peninsula called Italy here in the 20th. It is now the 19.32nd. In a few Centicenturies, provided I send the letter, a man of Italy will begin experimenting with the neutronic bombardment of uranium."

Harlan found himself horrified. "You will alter Primitive history?"

"Yes. It is our intention. In the new Reality, the final Reality, the first nuclear explosion will take place not in the 30th Century but in the 19.45th."

"But do you know the danger? Can you possibly estimate the danger?"

"We know the danger. We have viewed the sheaf of resulting Realities. There is a probability, not a certainty, of course, that Earth will end with a largely radioactive crust, but before that--"

"You mean there can be compensation for that?"

"A Galactic Empire. An actual intensification of the Basic State."

"Yet you accuse the Eternals of interfering--"

"We accuse them of interfering many times to keep mankind safely at home and in prison. We interfere once, once, to turn him prematurely to nucleonics so that he might never, never, establish an Eternity."

"No," said Harlan desperately. "There must be an Eternity."

"If you choose. It is yours to choose. If you wish to have psychopaths dictate the future of man-"

"Psychopaths!" exploded Harlan.

"Aren't they? You know them. Think!"

Harlan stared at her in outraged horror, yet he could not help thinking. He thought of Cubs learning the truth about Reality and Cub Latourette trying to kill himself as a result. Latourette had survived to become an Eternal, with what scars on his personality none could say, yet helping to decide on alternate Realities.

He thought of the caste system in Eternity, of the abnormal life that turned guilt feelings into anger and hatred against Technicians. He thought of Computers, struggling against themselves, of Finge intriguing against Twissell and Twissell spying on Finge. He thought of Sennor, fighting his bald head by fighting all the Eternals.

He thought of himself.

Then he thought of Twissell, the great Twissell, also breaking the laws of Eternity.

It was as though he had always known Eternity to be all this. Why else should he have been so willing to destroy it? Yet he had never admitted it to himself fully; he had never looked it clearly in the face, until, suddenly, now.

And he saw Eternity with great clarity as a sink of deepening psychoses, a writhing pit of abnormal motivation, a mass of desperate lives torn brutally out of context.

He looked blankly at Noys.

She said softly, "Do you see? Come to the mouth of the cave with me, Andrew?"

He followed her, hypnotized, appalled at the completeness with which he had gained a new viewpoint. His blaster fell away from the line connecting it and Noys's heart for the first time.

The pale streakings of dawn grayed the sky, and the bulking kettle just outside the cave was an oppressive shadow against the pallor. Its outlines were dulled and blurred by the film thrown over it.

Noys said, "This is Earth. Not the eternal and only home of mankind, but only a starting point of an infinite adventure. All you need do is make the decision. It is yours to make. You and I and the contents of this cave will be protected by a physiotime field against the Change. Cooper will disappear along with his advertisement; Eternity will go and the Reality of my Century, but we will remain to have children and grandchildren, and mankind will remain to reach the stars."

He turned to look at her, and she was smiling at him. It was Noys as she had been, and his own heart beating as it had used to.

He wasn't even aware that he had made his decision until the grayness suddenly invaded all the sky as the hulk of the kettle disappeared from against it.

With that disappearance, he knew, even as Noys moved slowly into his arms, came the end, the final end of Eternity.

- And the beginning of Infinity.