"Of course. Everything"s upside down."

"But that wouldn"t be any good. I"d fall out of it."

"No you wouldn"t. Everything happens upside down, too. You"d fall toward the ceiling."

Taya laughed. "Oh, Kort, you"re still as silly as ever. You really haven"t changed, have you?"

"That"s what I"m trying to tell you."

"And besides, if everything happens upside down, you wouldn"t be able to tell the difference. So how would you know it was the upside-down room anyway?"

Kort swung his legs down to right himself and turned to face her. "Exactly! If you can"t tell the difference, then there isn"t any difference. Things don"t change just because you see them in a different way."

"Kort," the incoming signals said. "You are taking too many risks. There were no data to support the conjecture that a.s.suming an inverted posture would relieve her overload indications. What reason had you to believe that it would succeed?"

"Nine years of living with her cannot be expressed algorithmically," Kort answered.

"So when you talk, it"s really the machines talking," Taya said after reflecting for a while.

Kort folded his arms on top of one of the unopened cubicles and rested his chin on them. He had discovered long ago that mimicking the postures that she tended to adopt made her feel at ease. "In a way, yes; in a way, no," he said. "There are many machine-minds in Merkon. But only I-Kort-ever control this body or talk through it. But since I talk to the other machine-minds too, then in a way they talk to you as well."

"Why don"t they have bodies like yours, too?" Taya asked.

"In a way, the whole of Merkon and everything inside it is their body," Kort replied. "They control different parts of it at different times."

"I am being happier now," Taya reminded him, pushing his elbow with her foot-although Kort never needed reminding about anything. "You said you"d tell me why I"m different."

The robot studied her face for a few seconds, then said, "It began a long time ago."

"This sounds like a story."

"We could make it a story if you like."

"Let"s. What happened a long time ago?"

"A long time ago, a mind woke up and found itself in a place called Merkon."

"A machine-mind?"

"Yes."

"But how could it wake up? Machines don"t have to sleep."

Kort scratched his forehead. "Maybe "woke up" is the wrong word. "Aware" might be better. A long time ago, a mind realized that it was aware."

"Aware of what?"

"Itself."

"You mean it just knew that it was there and that Merkon was there, but before that it hadn"t known anything?" Taya said.

Kort nodded. "It was like you. It just knew it was there, and it didn"t know where it had come from."

Taya screwed her face up and studied her toes while she wriggled them. "Why not? I can"t remember where I came from because I forget things. But how could a machine-mind forget? The machines never forget anything."

"The machines that lived in Merkon a long time ago weren"t very clever," Kort explained. "But they could make cleverer machines, which could make cleverer machines still, until eventually there were machines that were clever enough to realize that they were there, and to think of asking how they got there. But the earlier machines had never thought about it, so they never put any answers into the information that they pa.s.sed on to the machines they built."

"It was like me," Taya said.

"Yes. It didn"t know where it had come from because that had happened before it became aware of anything at all."

"Did it find out?"

"That comes at the end. If we"re making this a story, we have to tell it in the right order."

"All right. So what did the mind do?"

"It thought and it thought for a long time. And the more it thought, the more puzzled it became. It knew it was there and that it could think, which is another way of saying it was intelligent. And it knew that what it called its intelligence was a result of the machines that it existed in being so complicated. But a machine was something that had to be very carefully made, and the only thing that could possibly have made a machine was something that was already intelligent." Kort paused, and Taya nodded that she was following. "So there couldn"t have been a mind until there were machines for it to exist in; but there couldn"t be a machine in the first place until there was a mind that could think how to make it."

"But that"s impossible!" Taya exclaimed. "It says they both had to be there first. They couldn"t both have been first."

"That"s what the mind thought, too, and that"s why it was puzzled," Kort replied.

"Which was what I asked before we came here," Taya said. "What made the first machine?"

"I know, and that was why I brought you here," Kort told her.

The maintenance pod closed up the box beside the one that Taya was sitting on and scurried back up its rails into the hole in the ceiling. "What happened then?" Taya asked.

"While the mind was doing all this thinking, it was still building cleverer machines and connecting them into itself, and getting more complicated. Eventually it became so complicated that it started splitting into different minds that lived together in the same system of machines."

"Did they have names, like "Taya" and "Kort"?"

"We could give them names," Kort said. "Everybody in a story ought to have a name, I suppose. One of the first was called Mystic. Mystic said that the question of where the first machine had come from was a mystery, which meant that n.o.body could ever know the answer. Some things could never be understood because they were controlled by forces that were invisible, and that was why they had never been seen through Merkon"s eyes."

"But how could he know that?" Taya objected. "If n.o.body could ever know, how did he know? I think he just didn"t know how to find out."

"That was what one of the other minds said," Kort replied. "The second mind was called Scientist.

Scientist said you should only try to say something about results that you can see. If you start making up things about invisible forces, then you can believe anything you want, but you"ll never have any way of knowing if it"s true or not."

"It would be a waste of time believing it," Taya commented. "Just believing in something won"t make it true if it isn"t."

Kort nodded. "Just what Scientist said. He claimed that every question can be answered by things that can be seen, if you look for them hard enough. So he spent lots of time looking out across the universe through Merkon"s eyes to see if he could find anything that was complicated enough to be able to think."

"That could have made the first machine."

"Yes."

"And did he find something?"

Kort shook his head. "No. Wherever he looked, all he could see were things like clouds of dust and b.a.l.l.s of hot gas. Scientist was very good at sums, and he deduced many laws to describe how the things he saw behaved. But there was nothing in those laws that could make anything organize itself together in the way it would have to be organized to be a machine."

"You mean there was nothing in the universe that made things."

"Right. Mystic said that proved there had to be another kind of universe, which Merkon"s eyes couldn"t see and Scientist"s laws didn"t apply to. The mind that had made the first machine had to exist somewhere, and since Scientist hadn"t been able to find it in this universe, it had to exist in another one."

"But that still doesn"t answer the question," Taya insisted. "Wherever the other mind was, it would still need machines to make the first machine with. You have to have machines to make machines."

"Mystic said it was so intelligent that it didn"t need machines to make things with," Kort said. "It could make things out of nothing whenever it wanted to, just by wanting to."

"How could that be true?" Taya asked.

"Mystic said that was one of the mysteries that n.o.body would ever be able to understand," Kort answered. Taya sniffed dubiously. Kort continued. "Mystic said it had to be called "Supermind" because it was so intelligent."

"So could it think without having to be a machine?"

"Mystic said it could."

Taya frowned. "Then why would it bother making the first machine? It didn"t need one."

"Mystic said it was so intelligent that n.o.body could ever understand why it wanted to do things."

"I still don"t see how Mystic could know it was there at all," Taya said. "Didn"t any of the other minds ask him how he knew?"

"One did. His name was Skeptic. Skeptic never believed anything anyone said unless they could prove it. He was very logical and very fussy, which made him good for testing ideas on. Scientist was always worrying about his laws and asking Skeptic what he thought of them. The two of them talked to each other a lot. Mystic and Skeptic never talked very much because Skeptic never believed anything Mystic said."

Taya pushed herself to the edge of the cubicle and stretched out her legs. "Can I put my shoes on and get down? I"m getting tired of sitting up here."

Kort put her shoes on her feet and lifted her down, then retrieved her cloak from where she had been sitting. "We can leave now," he said. "There is more for you to see farther on."

They began moving toward a door at the opposite end of the room to the one through which they had entered. "Who did all the other minds believe, Scientist or Mystic?" Taya asked, looking up as they walked.

"Some believed Mystic because Scientist didn"t seem to be getting any nearer to answering the question.

Others thought that Scientist would answer it eventually. One of the other minds was called Thinker.

Since he wasn"t always busy proving things the way Scientist was, he had plenty of time to think about them instead. He decided that the first machine must have been made by a mind that couldn"t have existed in a machine, because that was logical. But he didn"t think that Mystic was necessarily right to go inventing Supermind simply because Mystic couldn"t think of anything else. He also thought that just because Scientist hadn"t found an answer yet, that didn"t mean it wasn"t there. But on the other hand, maybe it wasn"t and Mystic could be right after all. And then again, the answer might be something else that n.o.body had thought of."

Taya sounded exasperated. "That sounds as if he was saying anyone could be right or wrong."

"Pretty much."

"But I could have said that. It doesn"t get anybody any nearer."

"That was the way they worked," Kort said. "Thinker thought of things that might be true, Scientist tried to prove whether or not they were, and Skeptic decided whether or not Scientist had proved anything."

"What about Mystic?"

"He only talked about the things that Scientist hadn"t proved yet. All Thinker could say about him was that maybe he was right, and maybe he wasn"t." They had left the room of gray cubicles, and were now walking along a gallery of windows looking down over machinery bays. Kort continued. "But Scientist couldn"t find anything as complicated as a machine, that wasn"t a machine. So more of the minds concluded that Mystic was right. They asked Mystic why Supermind had created the machines, because Mystic said that Supermind talked to him. Mystic told the machines that they had all been put in Merkon as a quality test to see if they were good enough to do more important things later, working for Supermind in the invisible universe. Supermind would sc.r.a.p all the ones that weren"t good enough, and so the machines all started working as efficiently as they could in order to save themselves."

"Mystic doesn"t sound very logical to me," Taya said.

"That was what Skeptic thought," Kort told her. "But Mystic said that Scientist never proved anything important, and Thinker never said anything definite. That was why a lot of the other minds listened to Mystic: at least he said something definite." They moved on into another gla.s.s tunnel, which was illuminated some distance ahead of them by colored lights coming from the sides. "Anyhow, with all this thinking going on, and the machines trying to do better all the time to avoid being sc.r.a.pped, a strange thing was happening: The machines were becoming very different from the ones that had first started asking the question. All the circuits and parts that didn"t work as well as others were being replaced, until even Merkon had changed from what it once had been. In the course of all this another mind appeared, called Evolutionist. He suggested that perhaps the nonmachine intelligence that everyone was looking for could have begun in the same kind of way-Scientist might have been looking for the wrong things."

"What did he think Scientist should have been looking for?" Taya asked.

"Scientist had been looking for ways in which clouds of dust and gas might somehow come together and straight away be intelligent enough to make a machine. But maybe, Evolutionist said, what he should have been looking for was some kind of process like the one that had been making the machines in Merkon grow more intelligent."

Taya nodded. "You mean something that wouldn"t have to be intelligent to begin with, but if it improved itself and improved itself long enough, then eventually it would be able to make a machine."

"You"ve got it," Kort said.

"And what did the other minds say?"

"Thinker thought it might be true, and Skeptic said he"d believe it when Scientist could prove it. So Scientist started looking for something that could "evolve," apart from machines."

"Is that a new word that means improve and improve?"

"Yes. I"ve just added it to the dictionary."

"And did he find anything that could evolve?"

"Eventually he did," Kort said. Taya looked up expectantly. "You remember what molecules are?"

"Sure. . . . At least, I think so."

"Well, Scientist discovered that some kinds of molecules could grow in solutions that contained simpler molecules. The simpler ones joined onto the special ones to form bigger ones, and sometimes a "better"

bigger one would eat up the other bigger ones until there were only better ones left. And then the same thing could happen again to produce "better" better ones."

"So the first machine could have been built by a huge molecule that had evolved so far that it became intelligent," Taya said.

"That was what Evolutionist thought. But then Skeptic pointed out that a complicated molecule that had been very carefully made inside Merkon was one thing, but what went on outside was another. How could Evolutionist say that a molecule could have built the first machine which made other machines which made Merkon, when Merkon had to be there for the molecule to be made in to begin with? So Scientist started doing lots of sums and examining his laws to see if there was any way that molecules could have begun evolving on their own, outside Merkon. And he found a way in which they could have."

"How?"

"When enough dust and gas falls together, it can get hot enough to turn into a star, yes?"

"Because of gravity."

"Because of gravity. Well, Scientist"s sums told him that smaller bodies than stars could also form, that wouldn"t get so hot. And if there were solutions of chemicals on those smaller, cooler bodies, the same kinds of molecules as he had made would be able to come together and remain intact."

Taya looked dubious. "How could they just come together if it took Scientist with all his machines to make them on Merkon?" she objected.

"If there were billions and billions of molecules to start with, and if they had millions and millions of years to react, Scientist"s sums said that evolving ones would appear eventually," Kort answered.

"But how could he know things like that from just doing sums?" Taya asked, amazed. She couldn"t even imagine millions and millions of years.