“Surprisingly good agreement,” Hari allowed. The yellow surfaces of historical data merged cleanly with the other color skins, fluids finding curved levels. “And covering four millennia! No infinities?”

“That new renormalization scheme blotted them out.”

“Excellent! The middle Galactic Era data is the most solid, too, correct?”

“Yeah. The politicians got into the act after the seventh millennium. Dors is helpin’ me filter out the garbage.”

Hari admired the graceful blending of colors, ancient wine in transfinite bottles.

The psychohistorical rates linked together strongly. History was not at all like a sturdy steel edifice rigidly spanning time; it rather more resembled a rope bridge, groaning and flexing with every footfall. This “strong coupling dynamic” led to resonances in the equations, wild fluctuations, even infinities. Yet nothing really went infinite in reality, so the equations had to be fixed. Hari and Yugo had spent many years eliminating ugly infinites. Maybe their goal was in sight.

“How do the results look if you simply run the equations forward, past the seventh millennium?” Hari asked.

“Oscillations build up,” Yugo admitted.

Feedback loops were scarcely new. Hari knew the general theorem, ancient beyond measure: If all variables in a system are tightly coupled, and you can change one of them precisely and broadly, then you can indirectly control all of them. The system could be guided to an exact outcome through its myriad internal feedback loops. Spontaneously, the system ordered itself-and obeyed.

History, of course, obeyed no one. But for eras such as the fourth to seventh millennium, somehow the equations got matters right. Psychohistory could “post-dict” history.

In truly complex systems, how adjustments occur lay beyond the human complexity horizon, beyond knowing-and most important, not worth knowing.

But if the system went awry, somebody had to get down in the guts of it and find the trouble. “Any ideas? Clues?”

Yugo shrugged. “Look at this.”

The fluids lapped at the walls of the bottles. More warped volumes appeared, filled with brightly colored data-liquids. Hari watched as tides swept through the burnt-orange variable-space, driving answering waves in the purple layers nearby. Soon the entire holo showed furiously churning turbulence.

“So the equations fail,” Hari said.

“Yeah, big time, too. The grand cycles last about a hundred and twenty-five years. But smoothing out events shorter than eighty years gives a steady pattern. See-”

Hari watched turbulence build like a hurricane churning a multicolored ocean.

Yugo said, “That takes away scatter due to ‘generational styles,’ Dors calls it. I can take the Zones that consciously increased human lifespan. I time-step the equations forward, great-but then I run out of data. How come? I mine the history some, and it turns out those societies didn’t last long.”

Hari shook his head. “You’re sure? I’d imagine increasing the average age would bring a little wisdom into the picture.”

“Not so! I looked deeper and found that when the lifespan reached the social cycle time, usually about a hundred and ten Standard Years, instability rose. Whole planets had wars, depressions, general social illnesses.”

Hari frowned. “That effect-is it known?”

“Don’t think so.”

“This is why humans reached a barrier in improving their longevity? Society breaks down, ending the progress?”

“Yeah.”

Yugo wore a small, tight smile, by which Hari knew that he was rather proud of this result. “Growing irregularities, building to-chaos.”

This was the deep problem they had not mastered. “Damn!” Hari had a gut dislike of unpredictability.

Yugo gave Hari a crooked smile. “On that one, boss, I got no news.”

“Don’t worry,” Hari said cheerfully, though he didn’t feel it. “You’ve made good progress. Remember the adage-the Imperium wasn’t built in a day.”

“Yeah, but it seems to be fallin’ apart plenty fast.”

They seldom mentioned the deep-seated motivation for psychohistory: the pervasive anxiety that the Empire was declining, for reasons no one knew. There were theories aplenty, but none had predictive power. Hari hoped to supply that. Progress was infuriatingly slow.

Yugo was looking morose. Hari got up, came around the big desk, and gave Yugo a gentle slap on the back. “Cheer up! Publish this result.”

“Can I? We’ve got to keep psychohistory quiet.”

“Just group the data, then publish in a journal devoted to analytical history. Talk to Dors about selecting the journal.”

Yugo brightened. “I’ll write it up, show you-”

“No, leave me out of it. It’s your work.”

“Hey, you showed me how to set up the analysis, where-”

“It’s yours. Publish.”

“Well…”

Hari did not mention the fact that, now, anything published under his name would attract attention. A few might guess at the immensely larger theory lurking behind the simple lifespan-resonance effect. Best to keep a low profile.

When Yugo had gone back to work, Hari sat for a while and watched the squalls work through the data-fluids, still time-stepping in the air above his desk. Then he glanced at a favorite quotation of his, pointed out to him by Dors, given to him on a small, elegant ceramo-plaque:

Minimum force, applied at a cusp moment at the historical fulcrum, paves the path to a distant vision. Pursue only those immediate goals which serve the longest perspectives.

—Emperor Kamble’s 9th Oracle, Verse 17

“But suppose you can’t afford long perspectives?” he muttered, then went back to work.

The next day he got an education in the realities of Imperial politics.

“You didn’t know the 3D scope was on you?” Yugo asked.

Hari watched the conversation with Lamurk replay on his office holo. He had fled to the University when the Imperial Specials started having trouble holding the media mob away from his apartment. They had called in reinforcements when they caught a team drilling an acoustic tap into the apartment from three layers above. Hari and Dors had gotten out with an escort through a maintenance grav drop.

“No, I didn’t. There was a lot going on.” He remembered his bodyguards accosting someone, checking and letting it pass. The 3D camera and acoustic tracker were so small that a media deputy could walk around with them under formal wear. Assassins used the same artful concealment. Bodyguards knew how to distinguish between the two.

Yugo said with Dahlite savvy, “Gotta watch ‘em, you gonna play in those leagues.”

“I appreciate the concern,” Hari said dryly.

Dors tapped a finger to her lips. “I think you came over rather well.”

“I didn’t want to seem as though I were deliberately cutting up a majority leader from the High Council,” Hari said heatedly.

“But that’s what you were doin’,” Yugo said.

“I suppose, but at the time it seemed like polite… banter,” he finished lamely. Edited for 3D, it was a quick verbal Ping-Pong with razor blades instead of balls.

“But you topped him at every exchange,” Dors observed.

“I don’t even dislike him! He has done good things for the Empire.” He paused, thinking. “But it was… fun.”

“Maybe you do have a talent for this,” she said.

“I’d rather not.”

“I don’t think you have much choice,” Yugo said. “You’re gettin’ famous.”

“Fame is the accumulation of misunderstandings around a well-known name,” Dors said.

Hari smiled. “Well put.”

“It’s from Eldonian the Elder, the longest-lived emperor. The only one of his clan to die of old age.”

“Makes the point,” Yugo said. “You gotta expect some stories, gossip, mistakes.”

Hari shook his head angrily. “No! Look, we can’t let this extraneous matter distract us. Yugo, what about those bootleg personality constellations you ‘acquired’?”