“They are the only world there is,” said Kresh. “Her simulants are real-life people.”

“Of course, of course, but my point is that she knows they are imaginary, and yet has begun to believe in them. She believes in them in the way one might care about characters in a work of fiction, or the way a pet owner might talk to her nonsentient pet. On some level Unit Dee knows her simulants are not real. But she still takes a genuine interest in them, and still experiences genuine, if mild, First Law conflict when one of them dies and she might, conceivably, have prevented it. Causing the death of simulants has been extremely difficult for her.

“If she were to find out she had been killing real people-well, that would be the end. She might simply experience massive First Law conflict and lock up altogether, suffer brainlock and die. Or worse, she might survive.”

“Why would it be worse if she survived?” Kresh asked.

Soggdon let out a long weary sigh and shook her head. She looked up at the massive hemisphere and shook her head. “I don’t know. I can guess. At best, I think she would find ways to shut down the whole operation. We’d try to stop her, of course, but she’s too well hooked in, and she’s awfully fast. I expect she’d order power shutdowns, find some way to deactivate Unit Dum so he couldn’t run the show on his own, erase computer files-that sort of thing. She’d cancel the reterraforming project because it could cause injury to humans.”

“The best sounds pretty bad. And at worst?”

“At worst, she would try to undo the damage, put things back the way they were. “ Soggdon allowed herself a humorless smile. “She’d set to work trying to un-reterraform the planet. Galaxy alone knows what that would end up like. We’d shut her down, of course, or at least try to do so. But I don’t need to exaggerate the damage she could do.”

Kresh nodded thoughtfully. “No, you don’t,” he said. “But I still need to talk with her-and with Unit Dum. You haven’t said much about him, I notice.”

Soggdon shrugged. “There’s not much to say. I suppose we shouldn’t even call him a he-he’s definitely an it, a soulless, mindless, machine that can do its job very, very, well. When you speak with him, you’ll really be dealing with his pseudoself-aware interface, a personality interface-and, I might add, it is quite deliberately not a very good one. We don’t want to fool ourselves into thinking Unit Dum is something he is not.”

“But it sounds as if he could handle the situation if Unit Dee did shut down.”

“In theory, yes, Unit Dum could run the whole terraforming project by himself. In practice, all of us here believe you were quite wise not to put all your trust in a single control system. We need redundancy. We need to have a second opinion. Besides which, the two of them make a good team. They work well together. They are probably three or four times as effective working together as either would be alone. And anyway, we’re only a few years into a project that could take a century or more. It’s way too early to think about risking our primary operating procedure and trusting the whole job to backups. What if the backup runs into trouble?”

“All your points are well taken,” said Governor Kresh. “So-what are the precautions I should take in talking to them?”

“Don’t lose your temper if Unit Dee is condescending to you in some way. She doesn’t really think you’re real, after all. You are really nothing more than one of the game pieces, as far as she is concerned. Don’t be thrown off if she seems to know a great deal about you, and lets you know it. Don’t correct her if she gets something wrong, either. We’ve made various adjustments to her information files for one reason or another-some deliberate errors to make it seem like a simulation, and others we set up for some procedural reason or another. Try to remember you’re not real. That’s the main thing. As for the rest of it, you’ll be talking to her via audio on a headset, and I’ll be monitoring. If there’s anything else you need to know, I’ll cut in.”

Governor Kresh nodded thoughtfully. “Have you ever noticed, Dr. Soggdon, just how much of our energy goes into dealing with the Three Laws? Getting around them, trying to make the world conform to them?”

At first, the offhand remark shocked Soggdon. Not because she disagreed with his words-far from it-but because Kresh was willing speak them. Well, if the governor was in a mood to dabble with heresy, why not indulge in it herself? “I’ve thought that for a long time, Governor,” she said. “I think the case could be made that this world is in as much trouble as it is because of the Three Laws. They’ve made us too cautious, made us worry too much about making sure today is like yesterday, and far too timid to dare plan for tomorrow.”

Kresh laughed. “Not a bad line, that,” he said. “You might catch me stealing it for use in a speech one of these fine days. “ The governor looked from the Unit Dee Controller to the Unit Dum Controller, and then back up at Soggdon. “All right,” he said. “Let’s get this thing set up.”

“GOOOD MORRN-ING. GOVVVENORR Kressh.” Two voices came through the headphone to address him in unison-one a light, feminine soprano, the other a gravelly, slightly slurred, and genderless alto. They spoke the same words at the same time, but they did not synchronize with each other exactly.

The voices seemed to be coming from out of nowhere at all. No doubt that was an audio illusion produced by the stereo effect of the headphones, but it was nonetheless disconcerting. Alvar Kresh frowned and looked behind himself, as if he expected there to be two robots there, one standing behind each ear. He knew perfectly well there would be nothing to see, but there was some part of him that had to check all the same.

The whole setup seemed lunatic, irrational-but the iron hand of the Three Laws dictated that there be some such arrangement. Kresh decided to make the best of it. “Good morning,” he said, speaking into the headset’s microphone. “I take it I am addressing both Unit Dee and Unit Dum?”

“Thaat izz comect, Governorrr,” the two voices replied. “Somme vizzzitors finnnd iiit dissconcerrrting to hear usss both. Shalll we filllter ouut onne voice?”

“That might be helpful,” Kresh said. Disconcerting was far too mild a word. The two voices speaking as one was downright eerie.

“Very well,” the feminine voice said in his left ear, by itself, speaking with a sudden brisk, clipped tone, a jarring change from what had come before. Perhaps she found it easier to speak without the need to synchronize with Unit Dum. “Both of us are still on-line to you, but you will hear only one of us at a time. We will shift from one speaker to the other from time to time to remind you of our dual presence.” The voice he heard was almost excessively cheerful, with an oddly youthful tone to it. A playful voice, full of amusement and good humor.

“This higher-pitched voice I hear now,” Kresh said, “it is Unit Dee?”

“That is correct, sir.”

Suddenly the other voice, low-pitched, impersonal and slightly slurred, spoke into his right ear. “This is the voice of Unit Dum.”

“Good. Fine. Whatever. I need to speak with you both.”

“Please go ahead, Governor,” said Unit Dee in his left ear again. Kresh began to wonder if the voice-switching was some sort of game Unit Dee was playing, a way of putting him off his stride. If so, it was not going to work.

“I intend to,” he said. “I want to talk to you about an old project, from the period of the first effort to terraform this world!’

“And what would that be?” asked Unit Dee.

“The proposal to create a Polar Sea as a means of moderating planetary temperatures. I want you to consider an idea based on that old concept.”

“Ready to accept input,” said the gravelly, mechanical voice in his right ear. It was plain that very little effort had gone into giving Unit Dum a simulated personality. That was, perhaps, just as well. Kresh had the sense of talking to a schizophrenic as it was.