Authors: Greg Egan
Tags: #Science Fiction, #General, #Space Opera, #Fiction
He forced his way through a tangle of vines sprouting brilliant green flowers and almost collided with the paralyzed male, drifting alone between the branches. Carlo chirped in triumph. They’d made a hard choice and abandoned one friend, but the female they were still carrying was larger. And though they’d lightened their collective load, he couldn’t see it being much help to them: trying to share the burden as they moved through this painfully narrow labyrinth would only complicate the task.
“Lucia!” he called out. “They’ve left the male! Can you watch him? I’m going on.” He would not have put it past the arborines for one of them to double back and spirit the male away if he was left unattended.
“All right,” Lucia replied reluctantly.
Carlo couldn’t see his quarry. He waited, surveying the luminous forest around him, ignoring the mites that were starting to insinuate themselves into his broken skin. Then he caught the tell-tale twitch of a branch in the distance, and set off in pursuit once more.
The arborines had changed direction. Carlo had been more or less lost from the start, but at least he’d recognized when he’d been traveling from the outer tips of branches in toward the trunk. Now he was being led in some kind of arc, or possibly a helix, crossing from branch to branch around the axis of the tree.
It was exhausting work, propelling himself across these treacherous gaps full of fine twigs that scraped against him—sometimes snapping, sometimes rebounding, deflecting him unpredictably. But it had to be less punishing than penetrating deeper into the thicket of branches. His skin tingled, no doubt from trapped heat as much as every other insult, but whatever failures he might yet be forced to swallow he was not going to abandon this chase out of sheer lack of stamina.
Carlo could see the three arborines clearly now, framed between thick branches bearing radiant blue flowers. The ambulatory female gripped the paralyzed one with her right hands, while the male kept pace beside them, offering occasional nudges whose purpose and efficacy were hard to judge. The darkness behind them was tinged with the red moss-light of the cavern’s ceiling. They were heading straight for the canopy, Carlo realized. The female had seen him stranded there; she knew that if they leaped through the air to another tree he’d either be afraid to follow them, or his aim would be so bad that he’d never catch up with them.
Carlo quickened his pace, pushing off harder from each branch, trying to maintain momentum, fighting a powerful urge to be more cautious. Weightless or not, now that he had it fixed in his mind that he was moving
vertically
the idea had become imbued with a sense of danger. He had never been in a forest under gravity, but perhaps he’d inherited instincts attuned to his deep ancestors’ life in the trees—or attuned to the time when they’d begun to abandon them. A strong aversion to arboreal heights might have kept his forebears from dashing their skulls against the ground once they’d lost their cousins’ more graceful anatomy. But he couldn’t let his cousins win this race, least of all out of some misguided fear of falling. He shut out the warnings and kept climbing.
More and more moss-light was penetrating the canopy, but Carlo had the arborines fixed in his sight, and he could see that he was gaining on them. Their coordination as they swung between the branches was a marvel, and the male seemed to have taken on a kind of shock-absorbing role—pushing back on the paralyzed female when she threatened to tear herself out of her friend’s grip through sheer momentum—but all this heroic effort had a cost. They were flagging. They were not going to escape.
The male leaped off to one side, shrieking noisily, as if he imagined he could serve as a decoy. Carlo ignored him and forced himself onward; his own strength was dwindling rapidly, but he was sure he still had the edge. All he needed to do now was scare off the female, then he could rest for a few lapses and think through the logistics of joining up with Lucia and extracting their two specimens from the forest.
The female halted, clinging to a branch just a stretch or so ahead of him. Carlo stopped too, waiting for his adversary to flee, but instead she turned and defiantly wrapped three arms around her insensate friend.
Carlo swung onto a closer branch. The female glared at him balefully, her eyes glinting violet. Surely she was intelligent enough to understand that she risked paralysis herself? He opened his slingshot pouch and checked the contents; despite everything it had been through, the sturdier version Lucia had given him hadn’t spilt any darts.
As he took out the slingshot he caught a blur of motion in his rear gaze, but before he could react there were arms encircling his chest, a hand tugging on the slingshot, a fist pounding his tympanum and teeth buried in the side of his neck. The worst pain by far was in his tympanum; he stiffened the membrane and managed to seize hold of the offending fist. The male tried to pull free, without success, then redirected all his effort into his jaws.
Carlo retained just enough presence of mind not to start cursing aloud. His upper hands were already fully occupied and his lower hands couldn’t reach the jaw clamped to his neck. There was an urgent, combative tension keeping his whole body rigid, and his first attempts to change his form faltered from the sense that any relaxation would mean surrender. He kept trying. Finally his lower limbs softened, and he extruded enough flesh into them to let them stretch up to the arborine’s mouth. He forced his fingers between the creature’s teeth, hardening his fingertips into wedges, and tried to prise the jaws apart.
Gradually the arborine yielded, but while Carlo was focused on that battle the thing pulled the slingshot out of his hand and tossed it away. Carlo quickly plunged his hand into the pouch again and got hold of a dart; with a flick of the thumb he unsheathed it. The arborine grabbed his wrist and refused to let him take his hand from the pouch.
Carlo’s skin was feverish, but the animal’s flesh against him felt hotter. The scent of it was overpowering, but horribly familiar: it reminded him of the smell of his father before he’d died. He still had his hands in the arborine’s jaws; he pulled them further apart and twisted the head back sharply. This felt satisfying, but however much pain he was inflicting it didn’t weaken the arborine’s grip on him.
Carlo tried to extrude a fifth limb, but nothing happened. He let go of the fist that he’d stayed from battering his tympanum, sharpened the fingertips of his newly freed hand and plunged them into the arborine’s forearm just above the pouch. He felt the muscles below twitch and slacken; he’d disrupted some of the motor pathways.
The arborine appeared confused; it didn’t bother resuming its assault on Carlo’s tympanum, but before it could make up its mind what to do Carlo tore his hand free from the pouch and plunged the dart into the arborine’s shoulder. He felt the body grow limp immediately, but he still had to prise the lower arms from around his chest and shake the thing off him.
The females were gone.
Carlo looked around; his slingshot was caught on a branch nearby. He dragged himself over and grabbed it, then set off toward the canopy as fast as he could.
As he ascended, the light from the flowers above him thinned and faded and was gone. Suddenly he was in open air, in the murk again, with nothing but the forest’s decaying litter between him and the cavern’s red ceiling. He searched for the females, hoping the one who’d carried her friend so far might have needed one last rest before launching the pair to safety, but then he saw them. They were in the air, a couple of stretches away, drifting straight toward the safety of a neighboring tree.
Carlo loaded his slingshot, took aim and released the dart. A breeze stirred the dust and obscured his view, but when he had clear sight again the projectile was nowhere to be seen.
He tried again. His second dart sliced through the detritus and miraculously struck flesh—but he’d hit the female that Lucia had already paralyzed.
“No, no, no!” he pleaded. The arborines vanished into the murk; he waited helplessly, and when they appeared again they’d almost reached their sanctuary. Carlo reloaded and released, reloaded and released, aiming through the grit and swirling dead petals by memory and extrapolation until a single dart remained.
He couldn’t bring himself to use the last one blindly. He waited for the air to clear. Lucia knew the forest better than anyone living, but she’d been a child the last time an arborine had been captured. There were no experts at this. How many people would he need to beg from Tosco in order to succeed at this task by force of numbers alone?
He finally caught sight of the arborines, silhouetted against the light of the adjacent tree. They had separated; their outlines were distinct. Carlo waited for his indefatigable nemesis to reach out and drag her friend to safety, but both animals remained motionless. She wasn’t just weary. He had hit her.
They hadn’t drifted far in among the branches, but they’d be within reach of any determined allies. If he descended to the floor of the cavern, crossed through the undergrowth and climbed up the neighboring tree, there’d be no guarantee that the arborines would still be waiting for him.
Carlo looked up toward the ceiling, wondering if he should go back and fetch Lucia. But even that might take too long.
He dragged himself out along the branch he was holding, then grabbed another one and pulled the two together to the test the way they flexed. They were loose and springy; maybe an arborine could judge exactly how they’d recoil, but the task was beyond him.
Then again, if he aimed low he might face a long climb to his target, but he probably wouldn’t find himself stranded.
Carlo glanced down at his torn skin. He’d come too far to give up on the chase now. He crawled to the end of the swaying branch, holding it only with his lower hands, then pushed himself away into the air.
33
“W
e’ve hit a dead end,” Romolo confessed. “Just when the Rule of Two was starting to look plausible, we checked it against the second set of spectra and it fell apart.”
Carla glanced at Patrizia, but she appeared equally dispirited. They had been toiling over the spectra from the optical solid for more than a stint, but the last time they’d reported to her they had seemed to be close to a breakthrough.
“Don’t give up now!” Carla urged them. “It’s almost making sense.” She had hoped that the problem would yield to a mixture of focus, persistence and brute-force arithmetic—and it was easier to free her two best students from other commitments than to achieve that state herself. Someone had to supervise the experiments the Council had actually approved.
“Making sense?” Patrizia hummed softly and pressed a fist into her gut, giving Carla a pang of empathetic hunger. When things were going well there was no better distraction than work, but the frustration of reaching an impasse had the opposite effect.
“Why should the Rule of Two depend on the polarization of the beams?” Romolo demanded.
“And why the Rule of Two in the first place?” Patrizia added. “Why not the Rule of Three, or the Rule of One?”
Carla tried to take a step back from the problem. “The first set of spectra
does
make sense if every energy level can only hold two luxagens. Right?”
“Yes,” Romolo agreed. “But why? Once they’re this close together, luxagens simply attract each other. So how does a pair of luxagens get the power to push any newcomers away?”
“I don’t know,” Carla admitted. “But it would solve Ivo’s stability problem.” If each energy level could hold at most two luxagens, then beyond a certain point it would be impossible to squeeze more of the particles into each energy valley. That would be enough to prevent every world in the cosmos from collapsing down to the size of a dust grain.
Patrizia said, “For the first set of spectra, we made the field in the optical solid as simple as possible—using light polarized in the direction of travel for all three beams. With that kind of field, each luxagen’s energy only depends on its position in the valley. For the second set, we changed the polarization of one of the beams, so the luxagen’s energy depends on the way it’s moving as well as its position. But the strangest thing is that it looks as if there are more energy levels than there are solutions to the wave equation!”
Carla said, “I don’t see how that’s possible.” Two solutions—two different shapes for the luxagen wave—might turn out to have the same energy, but the converse was nonsensical. The luxagen’s energy couldn’t change without changing the shape of its wave.
Patrizia pulled a roll of paper from a pocket and spread it across Carla’s desk. The depth of the valleys in the optical solid had been chosen to ensure that they only had ten energy levels—limiting the possible transitions between them to a manageable number. But the data showed clearly that when one of the three beams was polarized so its field pointed at right angles to the direction of the light, the spectra split into so many lines that it took more than ten levels to explain them all.
“What if the luxagen has its own polarization?” Carla suggested. She’d ignored that possibility when first deriving the wave equation, largely for the sake of simplicity. “Depending on the precise geometry of the light field, the
luxagen’s
polarization could start affecting the energy—adding new levels.”
“Then it’s a shame we didn’t find a Rule of Three!” Romolo replied. “We could have said that the
true
rule was the Rule of One: in every valley, you can have at most one luxagen with a given energy
and
a given polarization. The Rule of Three would only hold for the simplest fields—where you couldn’t tell that the three luxagens were different, because their polarization had no effect on their energy.”
Patrizia turned to him. “But what if luxagens could only have two polarizations?”
Romolo was bemused. “Isn’t that like asking for space to have one less dimension?”
Carla wasn’t so sure; it could be subtler than that. She said, “Let’s make a list. If we’ve been working from false assumptions, what exactly would we need to have been wrong about in order to make things right?”