again, but Soggdon did not seem to be bothered by it. Having heard each voice by itself, Kresh was able to notice something that had escaped him before. When the two units spoke in unison, it was not merely the two chanting together. The voice of the two together spoke in a cadence that did not belong to either of the two speaking by itself. The unison voice made different word choices, responded in a way that was different from Dee or Dum. The unison voice was not merely two beings talking as one. It was the two merging into one new being, in some ways greater, in some ways lesser than the sum of its parts. Dee and Dum linked so intimately that they became a third, and distinct, personality. Or was it merely Dee who did so? If Dum was truly nonsentient, then he could have no personality. Plainly there were mysteries to delve into-but just as plainly they would have to wait for another day. "The Kresh simulant asked us to consider the result of producing a Polar Sea."
"Yes, I know," said Soggdon. "And I see you have produced an impressive planetary projection as a result. Would either or both of you care to comment on it?"
"Both willl speeak, and then eachhh," said the unison voice. "We havvve prrojected forward four ttthousand yearss, as we have found that a wellll-planned operrational sequenzzze will result in a zzzero-maintenance planetary ecologggy within apprrroximately three hundred years. In our projection, the planetary climmmate remainss intrinsically stable, selfffcorrecting, and self-enhancing throughout the period of the metasimulation. There is no apparent danger of recollapse evident in any of the data for the end of the metasimulation period."
Kresh frowned. Metasimulation? Then he understood. The unison voice was using the term to refer to a simulation inside a simulation-which was what it had been, so far as Dum and Dee were concerned.
Dum spoke next. "Reference to unit Dum's prior objections in regard to ecological and economic damage. Projections show that the damage to the general ecology and gross planetary product caused by digging inlets for the Polar Sea would be fully compensated for within fifteen years of project completion."
But if the first two aspects of the combined control system made it all seem wonderful, the third voice pulled everything back down to reality. "It all sounds quite splendid," said Dee. "There is, of course, the slight problem of it being quite impossible. We ran the metasimulation based on the assumption that it would be possible to dig the channels. It is not possible to dig them. An interesting exercise, I grant you-but it is not one that has a great deal of connection to the world of our simulation."
"I was afraid she was going to say that," Soggdon muttered as she switched off her mike. "You'd think she'd be the least sensible of the three possible personality aspects, but instead Dee's always the one to stick the pin in the balloon. She always reminds us of the practicalities."
"Maybe this time they're a bit more possible than you think," Kresh said. He keyed his own mike back on, and tried to phrase things so that he would not reveal that he had overheard the conversation with Soggdon.
"Unit Dee, that's a very promising projection there. I take it you think creating the Polar Sea would be a good idea?"
"It is a good idea that cannot be realized, Governor," said Unit Dee. "You do not have the resources, the energy sources, or the time to construct the needed inlets."
"That is incorrect," Kresh said. "It is possible there is a practical, doable, way to dig those inlets. I came here to have you evaluate the proposed procedure. I first wanted to see if the effort would be worthwhile. I see now that it would be."
"What is the procedure in question?" asked Unit Dee.
Kresh hesitated a moment, but then gave up. There was no way to describe the idea that didn't sound dangerous, desperate, even insane. Well, maybe it was all three. So be it. "We're going to break a comet up, and drop the fragments in a line running from the Southern Ocean to the Polar Depression," he said. Even as he spoke, he realized that he hadn't put any modifiers or conditionals in. He hadn't said they might, or they could, or they were thinking of it. He had said they were going to do it. Had he made up his mind without knowing it?
But Dum and