Freestyle meant implementing your mind on a substrate that underwent quantum divergence. One-way meant none of the end products of any version of the computation could be retrieved, and transferred back into your usual hardware. Rainzi was asking her to clone herself into a nuclear abacus-cum-time-bomb that would generate a multitude of different versions of her, while holding out no prospect of even one survivor.
Cass said haltingly, “No, I’m sorry. I can’t join you.” So much for feeling smugly unshockable for daring to contemplate cross-modal sex. She joked, “I draw the line at any implementation where I experience detectable weight changes every time I learn something.” Femtomachines shuffled binding energies equivalent to a significant portion of their own mass; it would be like gaining or losing half a kilogram several times a second, from the sheer gravity of your thoughts.
Rainzi smiled. “I thought you’d say no. But it would have been discourteous not to ask.”
“Thank you. I appreciate that.”
“But you’d see it as a kind of death?”
Cass scowled. “I’m embodied, not deranged! If a copy of my mind experiences a few minutes' consciousness, then is lost, that’s not the death of anyone. It’s just amnesia.”
Rainzi looked puzzled. “Then I don’t understand. I know you prefer embodiment, for the sake of having honest perceptions of your surroundings, but we’re not talking about immersing you in some comforting simulation of being back on Earth. Your experiment should last almost six picoseconds. Running on a strong-force substrate, you’d have a chance to watch the data coming in, in real time. Of course, you’ll receive a useful subset of the same information eventually, but it won’t be as detailed, or as immediate. It won’t be as real.”
He smiled provocatively. “Suppose the ghost of Sarumpaet came to you in your sleep, and said: I’ll grant you a dream in which you witness the decay of the Diamond Graph. You’ll travel back in time, shrink to the Planck scale, and see everything with your own eyes, exactly as it happened. The only catch is, you won’t remember anything when you wake. You say you don’t believe that the dreamer would be dying. So wouldn’t you still want the dream?”
Cass let go of one handhold and swiveled away from the wall. There wasn’t much point objecting that he was offering her a view billions of times coarser than that, of a much less significant event. It wasn’t a ringside seat at the birth of the universe, but it was still the closest she could hope to get to an event for which she’d already sacrificed seven hundred and forty-five years of her life.
She said, “It’s not the fact that I wouldn’t remember the experience. If you’ve lived through something, you’ve lived through it. What worries me is all the other things I’d have to live through. All the other people I’d have to become.”
Cass dated the advent of civilization to the invention of the quantum singleton processor. The Qusp. She accepted the fact that she couldn’t entirely avoid splitting into multiple versions; interacting with any ordinary object around her gave rise to an entangled system — Cass plus cloud, Cass plus flower — and she could never hope to prevent the parts that lay outside her from entering superpositions of different classical outcomes, generating versions of her who witnessed different external events.
Unlike her hapless ancestors, though, she did not contribute to the process herself. While the Qusp inside her skull performed its computations, it was isolated from the wider world — a condition lasting just microseconds at a time, but rigidly enforced for the duration — only breaking quarantine when its state vector described one outcome, with certainty. With each operating cycle, the Qusp rotated a vector describing a single alternative into another with the same property, and though the path between the two necessarily included superpositions of many alternatives, only the final, definite state determined her actions.
Being a singleton meant that her decisions counted. She was not forced to give birth to a multitude of selves, each responding in a different way, every time she found her conscience or her judgment balanced on a knife edge. She was not at all what Homo sapiens had actually been, but she was close to what they’d believed themselves to be, for most of their history: a creature of choice, capable of doing one thing and not another.
Rainzi didn’t pursue the argument; he followed her in silence as she clambered into the display chamber. This was a small cavity in the Quietener’s outer structure, not much larger than her room at the station, equipped with a single chair. There was no question of Cass being allowed any closer to the action; even the processor on which the Mimosans were running, scrupulously designed to spill as little noise into the environment as possible, was banished to the rim of the Quietener. Lacking the same antinoise features herself, she had to agree to be snap-frozen to a few Kelvin, three minutes before each run. Apart from being immobilized, this had no unpleasant side effects, but it served as an uncomfortable reminder of the fact that the closed-cycle “breathing” of her Mimosan body was pure placebo. Still, she’d been willing to put up with it twenty times so far, merely for the sake of sparing herself the three-second time lag for data to make its way back to the station.
As she took her place in the cryogenic chair, the other Mimosans began to appear around her. Teasing her, congratulating her on her stamina. Livia joked, “We should have had a wager as to whether or not the incremental targets would turn out to be a waste of time. You could have relieved me of all my worldly goods by now.” Livia’s sole material possession was a replica of an ancient bronze coin, carved from leftover asteroid metal.
Cass shook her head. “What would I have put up? My left arm?” They’d been right to do things Livia’s way, and Cass had long ago ceased resenting it. Not only was it safer, it was better science, testing each novel structure one by one.
It turned out that Livia was alluding to a real wager: Bakim admitted that he’d made a bet with Darsono that Cass would not remain at Mimosa to the end. But he was unable to explain the stakes to her; her Mediator couldn’t find a suitable analogy, and nothing she suggested herself was even close. No precious object or information would change hands, nor was there any token act of servitude or humiliation in store for the loser. Cass was amused by the bet itself, but it bothered her that she could only grasp half of what was going on. When her friends asked her about the Mimosans, would all her stories end with apologies for her own incomprehension? She might as well have visited one of the great cities back on Earth and spent her time living in a storm-water drain, having shouted conversations through a narrow grill with the people at street level, full of misunderstandings about objects and events she couldn’t even glimpse.
Rainzi had clearly been delegated to put the Nuclear Question to her, because no one else broached the subject. Cass found it slightly galling that they wouldn’t even suffer a moment’s embarrassment when they took up their superior vantage point. They wouldn’t depart, they wouldn’t abandon her; they’d simply clone their minds into the nuclear substrate. With no expectation of recovering the clones, the originals would have no reason to pause, even for a picosecond, while their faster versions ran.
The target graph appeared on the wall in front of her. The four distinctive node patterns they’d tried in every other combination were all present now. Just as virtual particles stabilized the ordinary vacuum — creating a state of matter and geometry whose most likely successor was itself — Cass’s four patterns steered the novo-vacuum closer to the possibility of persistence. The balance was only approximate: according to the Sarumpaet rules, even an infinite network built from this motif would decay into ordinary vacuum in a matter of seconds. At the Planck scale, that was no small achievement; a tightrope walker who managed to circum-navigate the Earth a few billion times before toppling to the ground might be described as having similarly imperfect balance. In reality, any fragment of novo-vacuum they managed to create would be surrounded from the start by its older, vastly more stable relative, and would face the inevitable about a trillion times faster.