a start, we still don’t know what the bulk symmetries of this system are. I’ve more or less given up talking about
“You’re joking!”
“No. In fact, it’s looking more likely every day.” Sophus glanced at Tchicaya meaningfully, as if he was waiting for the Preservationists' laudable openness to be acknowledged.
Tchicaya said, “That’s right. I watched one experiment myself, just a few hours ago.” Mariama smiled at him, envious at this slight head start.
He smiled back at her, hoping his face wasn’t betraying his confusion. At the instant he’d seen her standing on the observation deck, he hadn’t consciously assumed anything about the faction she’d be joining; such ephemeral concerns had been swept from his thoughts entirely. Now that she’d casually revealed in passing that she’d come here to support the side that he would have sworn she’d be committed to opposing, the one part of his mind that resonated with this fact was the oldest, crudest model he had of her: someone whose only role in life was to confound and unsettle him. The original Mariama, who he had imagined would go to any lengths, not so much to spite him as to prove that he had no hope of pinning her down.
Tchicaya dragged his thoughts back to Sophus’s comments.
Kadir and Zyfete had been nowhere near as explicit, but then they’d not been in the friendliest of moods. Kadir’s despair made more sense now, though; it went beyond his growing fears for his home world, and one more ordinarily frustrating encounter with the border.
Time-translation symmetry was the key to all their hopes of predicting how the novo-vacuum would behave. In ordinary physics, if two people performed the same experiment, one starting work at midnight while the other began at noon, their separate versions could be compared, very easily: you merely added or subtracted half a day, and all their data could be superimposed. That sounded too obvious to be worth stating, but the fact that it was possible, and the fact that any laws of physics had to be compatible with this process of sliding the two sequences of events together, was a powerful constraint on the forms such laws could take.
Everything that happened in the universe was unique, on some level. If that were not true, there’d be no such thing as memory, or history; there’d be no meaningful chronology at all. At the same time, it was always possible to unpick some features of an event from the complicated tapestry of its context, and demand that this tiny patch of reality look the same as countless others, once you knew how to orient them all for the purpose of comparison. Taking a step north on Turaev on your eighteenth birthday could never be the same as taking a step west on Pachner four thousand years later, but in analyzing these two admittedly singular activities, you could safely abstract the relevant joints and muscles from the surrounding thicket of biographical and planetological detail, and declare that the applicable laws of mechanics were precisely the same in both cases.
It had been obvious since the accident that whatever the Mimosans had created in the Quietener did not possess the same symmetries as ordinary space-time, which allowed the unique location, time, orientation, and velocity of any physical system to be stripped away, revealing its essential nature. Still less had anyone expected the Mimosan vacuum to obey the “internal” symmetries that rendered an electron’s phase or a quark’s color as arbitrary as the choice of a planet’s prime meridian.
But everyone studying the novo-vacuum had been relying on the assumption that these familiar regularities had merely been replaced by more exotic ones. Mathematicians had long had a catalog of possibilities on offer that dwarfed those realized in nature: more or fewer dimensions, different invariant geometric structures, novel Lie groups for the transformations between particles. All of these things would be strange to encounter, but ultimately tractable. And at the very least, it had been taken for granted that there was some prospect of using the results of sufficiently simple experiments to deduce what would happen when those experiments were repeated. Once you lost
Tchicaya said, “If you’re right, we’re wasting our time here.”
Sophus laughed. “I wish all Yielders were so easily discouraged.”
Tchicaya caught the change in Mariama’s demeanor as he was finally labeled for her. She did not appear surprised, or cooler toward him, but a look of resignation crossed her face, as if she was letting other possibilities slip away.
He replied, “I didn’t say I believed you. Now I know you’re just spreading misinformation.”
Sophus said, “The data’s all public; you should judge for yourself. But I’m giving a presentation later today that might interest you.”
“On why we should all give up and go home? Yielders first, of course.”
“No. On why we shouldn’t, even if I’m right.”
Tchicaya was intrigued. “Dishing out despair with one hand, taking it away with the other. You’re never going to drive us away like that.”
“I’m really not interested in driving anyone away,” Sophus protested. “The more people there are working on this, the sooner we’ll understand it. I’m happy to share my ideas with everyone?—?and if some Yielder beats me to the punch line because of it, and fails to show reciprocal generosity, what have I lost?”
“You’re not afraid we’ll get through the border first? And shore up what you hope to annihilate?”
Sophus smiled amiably. “There might come a point when that’s a real threat. If I’m ever convinced that we’ve reached it, I suppose I might change my strategy. For now, though, it’s like a game of Quantum Pass-the- Parcel: all the players work simultaneously to tear off the wrapping, and all the players share the benefits. Why convert to the classical version? This is faster, and much more enjoyable.”
Tchicaya let the argument rest. It would have been impolite to state the obvious: when Sophus finally decided that sharing his insights had become too risky, it would not be to his advantage to announce the fact. At that point, the most logical strategy would be to continue displaying the same generosity as he’d shown in the past, but to replace the genuine, hard-won conjectures he’d revealed to his opponents in the past with equally well- crafted red herrings.
When they reached Mariama’s cabin, Sophus left them. Tchicaya hung back in the corridor, unsure whether she wanted him to stay or go.
She said, “Would you come in, if you’re coming in?”
He sat cross-legged on the bed while she moved around the cabin. She’d included some physical ornaments in her transmission?—?a handful of carved rocks and blown-glass objects that the
“I traveled light, myself,” Tchicaya said teasingly. “It didn’t seem fair to ask them to cannibalize the ship to provide me with knickknacks.”
Mariama narrowed her eyes. “Aren’t you the puritan? Not to the point of amnesia, I hope.”
He laughed. “Not these days.” In the past, he’d left some rarely used memories behind in the Qusps of his body trail. With fullsensory recall, the amount of data mounted up rapidly, and there’d come a point when knowing precisely what it had been like to shake water out of his ears in a river on Gupta or roll over and fart while camping in a desert on Peldan didn’t really strike him as a crucial part of his identity.
Yet he’d gathered up all the trivia again, before any of the Qusps were erased. And now that there was nowhere he could store his memories in the expectation that they’d remain secure?—?even if he archived them with a fleeing acorporeal community, their safety would come at the price of accessibility?—?they all seemed worth dragging around with him indefinitely.
Mariama finally settled on the shelf by the bed as the place for an elaborately braided variant of Klein’s bottle. “Holding on to your memories is one thing,” she said. “It doesn’t stop you going over the horizon.”
Tchicaya snorted. “Over the horizon? I’m four thousand and nine years old! Take out Slowdowns and travel insentience, and I’ve barely experienced half of that.” Information theory put bounds on the kind of correlations anyone could sustain between their mental states at different times; the details depended on the structure of your mind, the nature of its hardware, and, ultimately, on the recently rather plasticized laws of physics. If there were unavoidable limits, though, they were eons away. “I think I can still lay claim to doing a far better job of resembling
