Грег Иган - Schild’s Ladder

"So well that I almost hate to do this. How strong do you think your legs are?"

"What?" It took a moment for Tchicaya to understand what he was suggesting. "Oh, no. Please — "

"Don’t go squeamish on me; we don’t have time. It would be hard to decide who to save if we were from the same modes, but I can start from backup with no delay. You’d be out of the picture for months."

That was true. The Rindler had run out of bodies, and there were currently about twenty new arrivals waiting. Tchicaya would have to join the queue. Normally, a delay like that would mean nothing compared to the centuries he’d lost to transit insentience, but Branco’s experiment had just guaranteed that every day from now on would be unique.

"I’ve never killed anyone," he said. His stomach was knotted with revulsion at the thought.

Yann didn’t quibble over the hyperbole. "And I’ve never died, in a body. Sex and death, all in one day. What more could an acorporeal ask for?"

The wave came into view again; they’d have a minute or less. Tchicaya struggled to clear his head. Yann was demanding no more of him than he’d demanded of Mariama. The sense of shame and selfishness he felt, at the thought of indulging his own visceral urge to survive at Yann’s expense, was the right thing to feel, but that didn’t mean he had to elevate it above every other consideration. Nor, though, did he have to annihilate the emotion in order to act against it. He would do what the situation required, because it would be a foolish waste for both of them to lose their bodies, but he wasn’t going to pretend that he was happy, or indifferent about it.

He took hold of Yann’s left hand, then released his iron grip on his shoulder so they could join right hands as well. He folded his knees up against his chest, then froze. The crest of the wave was thirty meters away. This was too complicated. They’d never have time.

Yann said calmly, "Give me your body. I’ve worked out the steps."

Tchicaya surrendered motor control, and they began to move together in a perfect, symmetrical ballet. It was as if his limbs had been gripped by a dozen firm, invisible hands, manipulating him without resistance. His back arched, his arms stretched painfully, but their fingers stayed tangled in a monkey grip as their legs forced their bodies apart, until their feet met, sole to sole.

Tchicaya said, "You made me an isotopy."

Yann laughed. "Nothing original, I’m afraid."

"It’s the thought that counts."

Tchicaya had become disoriented, but as they swung around together his line of sight fell from the stars to the approaching wave. The muscles in his legs tensed, and the pressure against his feet grew until he felt as if his arms would be torn from his shoulders.

Yann said, "See you later."

Their fingers parted.

Tchicaya clutched at the emptiness between them, then stopped himself and wrapped his arms across his chest. He was ascending at a shallow angle, back toward the point where the Scribe had been. As the crest approached, he curled into a ball, and it raced past beneath him, a flash of silver licking at his heels as he tumbled.

An elaborate grid of colored lines scarred the inside of the retreating wave, like the map of some kind of convoluted maze. The pattern shifted as he watched. There was a tantalizing logic to the changes — the lines weren’t dancing about at random — but deciphering it on the spot was beyond him. All he could do was record the sight.

Drained for a moment of every other concern, Tchicaya locked his gaze on the retreating enigma.

Everything had changed, now. Whatever Branco had revealed, or created, the wall between the worlds had finally been breached.

"Everyone complains about the laws of physics, but no one does anything about them."

Tchicaya turned away from the control panel. He hadn’t heard Rasmah entering the Blue Room.

"It’s an old joke they used to tell, back on Maeder," she explained, crossing the wide, empty floor. "Which just goes to show how much work it takes to send a bad meme off to smallpox heaven."

"Don’t count on having done that," Tchicaya warned her. "I believe the original version was Everyone complains about human nature. When the second half became patently false, the meme just shifted context. You can tear the meaning right out of these one-liners, and they’ll still find a way to keep propagating."

"Damn." She sat beside him. "So what are the laws, right now?"

"As far as I can tell, we have a macroscopic SO(2,2) symmetry, and E7 as the gauge group." He gestured at the display. "Nothing we haven’t grabbed before, generically, though the details of the Lagrangian are unique." Tchicaya laughed. "Listen to me. I really am getting blasé about this."

"Seen one universe, seen them all." Rasmah leaned closer to examine the symmetry diagrams that the software had guessed from some partial results, and was now proceeding to test further with the Left Hand.

She glanced at the endurance clock. "Thirteen minutes? That’s close to the record. You think this might — " Tchicaya glowered at her, and she laughed. "Don’t tell me: I’m jinxing the result."

"Hardly. I’m just growing a little impatient with the idea that we keep grabbing dynamics, over and over, in the hope that one of them will turn out to be stable. It’s never going to happen."

"You think not?" Rasmah pursed her lips. "Okay. It’s no use just complaining, though. What do you want to do about it?"

Tchicaya made a gesture of helplessness.

She regarded him with disappointment. "Are you this lazy about everything?"

She was only teasing, but the accusation stung. Rasmah had been on the Rindler just six months longer than he had, but she’d already contributed substantially to several projects. Having helped to design the spectrometer that had been lost with the Scribe, she’d gone on to improve the design still further for the models used in both the Left and Right Hands. The Scribe’s replacement had been planned as a single machine, but when attempts to renegotiate the protocols for its shared use collapsed for the seventh time, even the most ecumenical researchers had lost patience, and agreed to the duplication.

Tchicaya stretched his arms. "I’ve certainly had enough of staring at this for one day. Are you here to take over?"

"Yes." She smiled and added, "But I’m early, so I’m afraid you can’t actually leave yet."

The destruction of the Scribe, and the end to cooperation between the factions, had delayed follow-ups to Branco’s experiment, but once the two Hands were in place and gathering data, everybody on the Rindler had been riveted by the results. For months, the Blue Room — where the Left Hand’s data was displayed, now that trips to the border were considered imprudent — had been packed with people twenty-four hours a day, and it was no secret that the Preservationists had reacted in the same way.

Branco’s technique appeared to have confirmed Sophus’s original assertion: the novo-vacuum did not obey any single analog or extension of the Sarumpaet rules. It was possible to correlate a macroscopic portion of the near side of the border with parts of the total far-side state that did obey specific rules, but each time the experiment was repeated, the rules were different. All of Sarumpaet’s carefully reasoned arguments about which patterns of nodes in a quantum graph could persist as particles had been revealed as utterly parochial; the larger truth was, the ordinary vacuum that dominated the near side was correlated with sequences of graphs that behaved in that particular fashion, so it hid the fact that they were really just part of a superposition of countless other possibilities. The quantum subtleties that could, in principle, render the whole superposition visible were buried in the sheer number of details that would have had to be tracked in order to observe it.