Again and again, star-spanning realms collapsed under the weight of excessive taxation. Sometimes the taxes supported mercenary armies which defended against neighbors, or which simply kept domestic order against centrifugal forces. Whatever the ostensible cause of taxes, soon enough the great cities became depopulated, as people fled the tax collectors, seeking “rural peace.”
But why did they do that spontaneously?
“People.” Hari sat up suddenly. “That’s what we’re missing. “
“Huh? You proved yourself-remember? the Reductionist Theorem?-that individuals don’t matter.”
“They don’t. But people do. Our coupled equations describe them in the mass, but we don’t know the critical drivers.”
“That’s all hidden, down in the data.”
“Maybe not. What if we were big spiders, instead of primates? Would psychohistory look the same?”
Yugo frowned. “Well…if the data were the same…”
“Data on trade, wars, population statistics? It wouldn’t matter whether we were counting spiders instead of people?”
Yugo shook his head, his face clouding, unwilling to concede a point that might topple years of work. “It’s gotta be there.”
“Your coming in here to get details of what the rich and famous do at their revels-where’s that in the equations?”
Yugo’s mouth twisted, irked now. “That stuff, it doesn’t matter.”
“Who says?”
“Well, history-”
“Is written by the winners, true enough. But how do the great generals get men and women to march through freezing mud? When won’t they march?”
“Nobody knows.”
“We need to know. Or rather, the equations do.”
“How?”
“I don’t know.”
“Go to the historians?”
Hari laughed. He shared Dors’ contempt for most of her profession. The current fashion in the study of the past was a matter of taste, not data.
He had once thought that history was simply a matter of grubbing in musty cyberfiles. Then, if Dors would show him how to track down data-whether encoded in ancient ferrite cylinders or polymer blocks or strandware -thenhe would have a firm basis for mathematics. Didn’t Dors and other historians simply add one more brick of knowledge to an ever-growing monument?
The current style, though, was to marshal the past into a preferred flavor. Factions fought over the antiquity, over “their” history vs. “ours.” Fringes flourished. The “spiral-centric” held that historical forces spread along spiral arms, whereas the “Hub-focused” maintained that the Galactic Center was the true mediating agency for causes, trends, movements, evolution. Technocrats contended with Naturals, who felt that innate human qualities drove change.
Among myriad facts and footnotes, specialists saw present politics mirrored in the past. As the present fractured and transfigured, there seemed no point of reference outside history itself-an unreliable platform indeed, especially when one realized how many mysterious gaps there were in the records. All this seemed to Hari to be more fashion than foundation. There was no uncontested past.
What contained the centrifugal forces of relativism-let me have my viewpoint and you can have yours-was an arena of broad agreement. Most people generally held that the Empire was good, overall. That the long periods of stasis had been the best times, for change always cost someone. That above the competing throng, through the factions shouting what were essentially family stories at each other, there was worth in comprehending where humanity had passed, what it had done.
But there agreement stopped. Few seemed concerned with where humanity, or even the Empire, was going. He had come to suspect that the subject was ignored, in favor of your-history-against-mine, because most historians unconsciously dreaded the future. They sensed the decline in their souls and knew that over the horizon lay not yet another shift-then-stasis but a collapse.
“So what do we do?” Hari realized that Yugo had said this twice now. He had drifted off into reverie.
“I…don’t know.”
“Add another term for basic instincts?”
Hari shook his head. “People don’t run on instinct. But they do behave like people-like primates, I suppose.”
“So…we should look into that?”
Hari threw up his hands. “I confess. I feel that this line of logic is leading somewhere-but I can’t see the end of it.”
Yugo nodded, grinned. “It’ll come out when it’s ripe.”
“Thanks. I’m not the best of collaborators, I know. Too moody.”
“Hey, never mind. Gotta think out loud sometimes, is all.”
“Sometimes I’m not sure I’m thinking at all.”
“Lemme show you the latest, huh?” Yugo liked to parade his inventions, and Hari sat back as Yugo accessed the office holo and patterns appeared in midair. Equations hung in space, 30-stacked and each term color-coded.
So many! They reminded Hari of birds, flocking in great banks.
Psychohistory was basically a vast set of interlocked equations, following the variables of history. It was impossible to change one and not vary any other. Alter population and trade changed, along with modes of entertainment, sexual mores, and a hundred other factors.
Some were undoubtedly unimportant, but which? History was a bottomless quarry of factoids, meaningless without some way of winnowing the hail of particulars. That was the essential first task of any theory of history-to find the deep variables.
“Post-diction rates-presto!” Yugo said, his hand computer suspending in air 30 graphs, elegantly arrayed. “Economic indices, variable-families, the works.”
“What eras?” Hari asked.
“Third millennia to seventh, G.E.”
The multidimensional surfaces representing economic variables were like twisted bottles filled with-as Yugo time-stepped them-sloshing fluids. The liquids of yellow and amber and virulent red flowed around and through each other in a supple, slow dance. Hari was perpetually amazed at how beauty arose in the most unlikely ways from mathematics. Yugo had plotted abstruse econometric quantities, yet in the gravid sway of centuries they made delicate arabesques.
“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?”