“Quite true; there is, however, a way to compensate for them. It is done through simple redundancy and comparison. After we perform an electronic download from a brain, we create three identical copies. Each of those copies, as you observed, is subject to statistical change because of quantum effects. Periodically, we therefore perform a complete bit-by-bit comparison of all three copies. Occasionally, one copy will show a difference from the other two. We attribute that change to a quantum fluctuation, and we correct the variant copy at that point to agree with the other two. It is, of course, mathematically possible for two quantum changes to take place in the stored brain map, on the same element of information and at the same time. That would produce three different versions, and there would be no way to decide which one was true to the original.

Fortunately, the probability of such an event is so small as to be of no concern.”

“I assume you’ve done all this to somebody?”

“More than that.” The Servitor lacked the means for a physical expression of embarrassment, but the voice slowed and changed. “For the past fourteen million years, I have been applying the technique to you. As soon as the technology permitted a complete download, I performed one of you. Since it was held in a totally dormant condition, and since you were still in the cryowomb, I felt that I had not violated your instructions.”

“You mean I’ve been downloaded already, without ever being asked? You’ve got a nerve.”

“What other option did I have? You ordered me to leave you unchanged in the cryotank, but leaving you there would itself change you. The only way to guarantee that you remained unaltered was to monitor changes in your frozen brain through triple redundancy checks on the downloaded versions, and then correct you appropriately in the cryotank. I can vouch for the effectiveness and reliability of the method, since it is close to the one that I employ on my own composite.”

“How do you know that you don’t change, Milton? You might be different than you were yesterday.”

“And you may not be the Drake Merlin who went into cryosleep, or the same person who met with Trismon Sorel. No one can prove that they are what they were. I can say only this: uploading represents your only chance of remaining unchanged into the far future.”

“What about my body?”

“Your original body?” Ariel answered the question. “It becomes of no interest. Its performance, without electronic update, must gradually degrade. We would propose to leave it in the cryowomb.”

“My body is of no interest?”

“Certainly. You were disposing of your body, cell by cell, every hour and minute that you were alive. Ask yourself, where is the body that you wore when you were five years old? Where is the body in which you first met your beloved Anastasia? They are gone, stranded far back upon the banks and shoals of time. It is only your mind, the essential spirit of Drake Merlin, that floats free toward the uncharted ocean of the future.”

“Ariel, I don’t know you at all; but if you were back in my own time I’d be worried. I once had a teacher who told me, ‘Watch out when the talk gets molto legato’ — very smooth. Too smooth, and too flowery. What are you leaving out?”

“You had a suspicious-minded teacher, Drake Merlin. Very well. There are several other things that should be said. The first concerns Ana. Her full genome is already in electronic storage, so future cloning would be trivial. But there is no ‘complete Ana’ available for electronic download. Her brain can yield no more than a random chaos of disconnected elements. Their transference would be pointless.”

“If I move to electronic form, whatever remains of Ana must move with me.”

“I suspected that would be your reply. But it is really quite illogical. If her personality could ever be restored, the existence of primitive brain residues will not be a factor.”

“So you say — now. But I’ve heard too often that nothing can be done for Ana. Both of us get downloaded, or neither one.”

“We hear you.” Ariel nodded in resignation. “Milton?”

“It will be done.”

The Servitor vanished. Ariel looked more pensive. “We have debated the wisdom of mentioning this next item,” he said. “We do not wish to arouse in you hopeless and unrealizable expectations. In fact, had it not been necessary to contact you concerning your removal from the cryowomb, we would have remained silent.

But having gone so far, I will continue. Your goal, for fourteen million years, has been to restore Ana to the form that you knew — not merely her body, but her whole personality.”

“And I’ve been told, over and over, that it’s quite impossible. Are you telling me that it isn’t?”

“It is impossible, today and for the known future. The question is, will it always be impossible? What I can tell you is this: whether Ana’s restoration is feasible or infeasible, in principle, in the very long-term future, does not depend on your actions or on my actions. It depends on the overall nature of the universe itself. And it is because our perceptions of that future have been changing that I am willing to discuss it with you now.”

“You’ve lost me. Totally.”

“As I was afraid I might. It is not easy to explain in a way that you will understand, or to know where to start so as to maximize the probability of your comprehension. But let us begin with a question: Do you know the difference between an open universe and a closed universe?”

“I know what the terms used to mean, at the time that I was frozen.”

“The notions have not changed, except possibly in minor details. The more distant galaxies recede from us, and more distant galaxies recede faster.”

“Even in my time, most people knew that.”

“Then the definitions with which you are familiar still apply. In an open universe, the galaxies go on receding from each other, forever. In a dosed universe, they one day reverse their motion and begin to approach each other. In a closed universe, the end point for that approach is a collapse to a point of infinite density, pressure, and temperature. Is that clear?”

“Clear, and totally irrelevant. I’m interested in restoring Ana, not in discussing cosmology.”

“That is understood. But the two are not unrelated.

Permit me to proceed. Whether or not the universe is open or closed depends on only one thing: the overall density of matter within it. If that density is too low, the universe must be open. If the matter density is high enough, past a critical value, the universe must be closed. What I say next may seem very difficult to you, and the minds of my

composite are not sure that you can ever understand it fully; but the possibility of restoring Ana — your original Ana — depends on whether the universe is open or closed. Hence it depends on the density of matter, or more strictly speaking on the mass-energy density of the universe.”

“You are quite right, I don’t understand you. But if I did, so what? Either the universe is open, or it is closed.” Drake could not conceal his impatience. He realized that he did not fit well into the world of Ariel and Milton. He was too focused, too direct, too impetuous and emotional, a living fossil atavism in a gentler and easier society. He did not know what the changed physical form of humanity looked like, but his guess was that nails and teeth had long gone. He alone possessed residual claws and fangs.

“We must be patient.” Ariel himself showed neither anger nor impatience. “If your original training had perhaps been in mathematics and physics, rather than in music, this would be simpler. But we will work with what we have.” There was no implied criticism, as Ariel continued, “Certain other things become possible in a closed universe. Such a universe possesses, as I said, a single, final end point: an eschaton. At that eschaton, that ultimate stage of confluence of all things, the universe contracts to a singularity. Everything converges, everything meets. This was known to scientists and philosophers at the time of your own birth, who sometimes referred to it as the Omega Point.