"I understand, Derec. "

"Continue, Thales."

"Nothing there?" Rana said. She waved a hand at the screens displaying the shattered remnants of the RI. "That's a lot of damage for nothing."

"Those sites were shut down," Derec said. "I'd love to know how they did that without leaving a physical trace, though. Something should be there, even if it's only an I/O port. Which reminds me, I got in there last night."

"Where? Union Station?"

"Back in the service sections, yes. I found something…" He went to his own console and retrieved the paper with the sample. "I need this analyzed," he said, opening it. "This was all through the circuitry in one of the maintenance nodes. It's hard and brittle. I hope there's enough here."

"I'll set Thales up on an analysis," Rana said, peering at the flakes suspiciously.

Derec glanced at the screens. "A positronic brain is joined to its realtime perception in a one-to-one relationship. It has to be that way or interpretive errors creep in and there's a kind of subjective drift."

"But robots interpret things all the time."

"True, but they have their core template to use as a standard. If you look at how they interpret you'll see that they're damnably literal. There was a classic case once of a newly uncrated robot completely disbelieving that humans had built it. The only evidence it could see were the humans supervising it and clearly they couldn't build one, so it must have been a lie. The Three Laws prevented it from doing other than its duty to protect and obey them, but only within certain limits, and it came to believe that robots were created by another machine."

"I thought that was apocryphal."

"Maybe. I've heard it said that the core template came directly out of that incident. But apocryphal or not, it illustrates the point. Positronic robots rely on the concrete to function. If they didn't, they could easily develop neuroses based on abstract concepts of humans they don't even know coming to harm."

"Robots having an existential crisis."

"Something like that. So we give them strict associational and sensory parameters by which to recognize what is real. That way they can determine optimum hierarchical responses to orders given by humans that may conflict with First Law imperatives and likewise permit them to make similar assessments in Third Law situations. Judgements like that demand concrete definitions."

"But what if you substituted those definitions with others? Or one set of perceptions with a different set?"

"They're designed to shut down if they detect that kind of sensory shift. You ' d have to actually bypass their sensory apparatus to do that, but bypass it without any interruption in the sensory input, and consistent with the core template."

Rana tapped one of the screens. "This brain thought it was playing a game. All it perceived, apparently, was the game. The game became its concrete definition."

"Which is impossible. Any code coming in from outside would cause a complete disruption of normal function."

"Unless it didn't come from outside."

"You mean like a parallel system built into its matrix?"

"Bogard worked that way."

"In a very limited fashion. Bogard's buffers simply bypassed crisis situations. It still perceived reality-"

"It just conveniently forgot some of it. What's the difference?"

None, Derec thought, staring at the screens. He had recognized the similarity in the paradox loops the other night. He had hoped it had been a fluke, but Rana had a point. Someone had devised a more complete way to divert a positronic matrix, and not just part of it.

The com chimed.

"Yes?"

"Mr. A very?"

"Speaking."

"This is Ambassador Chassik."

"Yes, Ambassador," Derec said, wincing. "I apologize for not returning your calls yesterday, but I was out of the lab-"

"I understand that, Mr. Avery. I've reached you now and that's fine. I wanted to get together with you to discuss certain matters concerning the removal of the RI from Union Station."

Derec glanced at the time. Almost six-thirty. "It's rather early, Ambassador. When did you have in mind?"

"The sooner the better. I'll send a limo."

"Now? But-"

"Thank you, Mr. Avery. I'll see you in a short while."

"Don't you love not having to make up your own mind?" Rana asked, grinning. Gale Chassik had the heavy look of someone who had done considerable physical labor during his life, which was incongruous in his case as he was a Solarian. Spacers did not get unnecessarily physical; they left that to their robots.

"I apologize for the circumstances, Mr. Avery," he said, pouring two glasses of amber fluid. He set one on the table beside Derec and took his own to the chair opposite. "Unfortunate times."

"How can I help you, Ambassador?" Derec asked, ignoring the glass. He folded his hands in his lap and waited.

"I wanted to have a talk with you about the Union Station RI."

"In what respect?"

"Your analysis of its condition. What you think happened."

"I have no idea what happened. "

"It's been two days-"

"Nearly three, Ambassador, and Phylaxis was removed from any involvement with it at the end of the first day."

Chassik frowned. His forehead seemed to contract. "Removed. But I understood-"

"Normally, Phylaxis Group would be doing the forensics, but Special Service assumed full control of the investigation and barred us from all the relevant material. Surely you knew."

"Your people have been working with us on decommissioning the mobile units. I assumed…"

Derec nodded. "To answer your question, sir, I have no idea what happened to the RI. The unit is a Solarian brain, isn't it? The company that did the original installation is removing it. Didn't they tell you any of this?"

Chassik snorted. "Terran regulations. They aren't allowed to discuss it with anyone, including me, until such as time as, et cetera. I'm sure you've heard the same excuses." He narrowed his eyes at Derec. "You aren't even doing oversight on its removal?"

"No, sir."

"Hmm. Odd."

"I can't disagree. "

"Well. Do you have any theories, Mr. Avery?"

"No, not even a hypothesis. At best I would be making a wild guess."

"Please."

"Somehow, coding was introduced into the RI that effectively distracted it from its primary responsibilities and redirected it. When the assault occurred, the RI was playing. It never saw what was happening."

"That's not possible."

"Again, I can't disagree. Without access to the unit, though, I can't begin to tell you why or how."

Chassik sipped his drink thoughtfully for a few moments. "Mr. Avery, I don't think I need tell you what sort of consequences we're looking at. I don't believe it's unlikely that relations with Earth could be severed."

Derec wanted to argue, but in truth what Chassik said seemed all too likely. One of the core issues of the conference, surrounded by all the trade talk and good will hype, was an agreement to allow robotic inspection of all Earth-Spacer shipping, in both directions. That meant allowing robots onto Terran vessels, a condition too few on Earth approved. It only seemed possible because of Eliton's efforts and the general esteem which Ambassador Humadros commanded and the fact that a great deal of money was involved. The Union Station RI and its satellite systems had been intended to showcase positronics on Earth, to "educate" Terrans and ease some of the prejudice. Now that it had failed so dramatically and catastrophically…

"I'm not sure what I could do to help, Ambassador," Derec said finally.

"Solaria stands to lose a great deal over this incident. Our reputation is at stake, here and at home. So you will understand my desire to know as much as possible about what happened. Would you be willing to do an analysis of the RI after it's been removed from Union Station? Off the record?"

"Off… I'm not sure I understand."

"On the quiet. I'm afraid it would not be authorized by anyone other than me. I could… 'borrow' the unit before it gets shipped back to Solaria."

"What good would that do? If I found something"

"Then it becomes my affair and I could do something with it. But without any knowledge of what happened, I'm helpless."

"It would have been better had the unit not been removed."

Chassik shrugged. "I can't stop it."

"Let me think about it, Ambassador," Derec said. "I'm not sure such an analysis would give you anything worth using. Off-site like that, without any kind of witness to the process, it could be claimed that anything I find is manufactured."

"Would it be?"

"What?"

"Claimed. You know these Terrans a little better than I, perhaps. You've been here longer."

"Think about it, Ambassador. Under similar circumstances, what would you claim? They aren't really that much different."

Chassik's eyebrows raised fractionally, but he nodded and smiled. "Don't take too long to give me your answer, Mr. Avery. There's a window of opportunity here."

"I understand, Ambassador."

Chassik pointed at the glass beside Derec. "You didn't touch your drink."

"It's a little early for me."

"Too bad. Something called Beam's Choice. I must confess, I don't find much about Earth superior, but they make fine whiskey." He finished his own glass. "A present from one of their industrialists. They like giving tokens here."

"When they can."

Chassik nodded and stood. "It was pleasant talking to you, Mr. Avery. And do let me know soonest on your decision."

"Yes, sir. Thank you."

Derec followed the waist-high mobile unit down the corridors to the elevator, trying to work loose the tightness between his shoulders. Nothing just said made any difference to anything; the entire meeting could have been done by comlink with the exception of the illicit offer to allow. Phylaxis access to the RI after its removal from Union Station. So that, Derec decided, had been the true purpose of the meeting.