Collected short fiction.., p.143
Collected Short Fiction of Greg Egan, page 143
Francine turned towards me. The skin around her eyes was grey and swollen, and I could see how much effort it took for her to meet my gaze. She drew her hands out from under the bedclothes, and let me hold them; they were freezing.
After a while, she started sobbing, but she wouldn’t release my hands. I stroked the back of her thumb with my own thumb, a tiny, gentle movement.
2020
“How do you feel now?” Olivia Maslin didn’t quite make eye contact as she addressed me; the image of my brain activity painted on her retinas was clearly holding her attention.
“Fine,” I said. “Exactly the same as I did before you started the infusion.”
I was reclining on something like a dentist’s couch, halfway between sitting and lying, wearing a tight-fitting cap studded with magnetic sensors and inducers. It was impossible to ignore the slight coolness of the liquid flowing into the vein in my forearm, but that sensation was no different than it had been on the previous occasion, a fortnight before.
“Could you count to ten for me, please.”
I obliged.
“Now close your eyes and picture the same familiar face as the last time.”
She’d told me I could choose anyone; I’d picked Francine. I brought back the image, then suddenly recalled that, the first time, after contemplating the detailed picture in my head for a few seconds — as if I was preparing to give a description to the police — I’d started thinking about Francine herself. On cue, the same transition occurred again: the frozen, forensic likeness became flesh and blood.
I was led through the whole sequence of activities once more: reading the same short story (“Two Old-Timers” by F. Scott Fitzgerald), listening to the same piece of music (from Rossini’s The Thieving Magpie), recounting the same childhood memory (my first day at school). At some point, I lost any trace of anxiety about repeating my earlier mental states with sufficient fidelity; after all, the experiment had been designed to cope with the inevitable variation between the two sessions. I was just one volunteer out of dozens, and half the subjects would be receiving nothing but saline on both occasions. For all I knew, I was one of them: a control, merely setting the baseline against which any real effect would be judged.
If I was receiving the coherence disruptors, though, then as far as I could tell they’d had no effect on me. My inner life hadn’t evaporated as the molecules bound to the microtubules in my neurons, guaranteeing that any kind of quantum coherence those structures might otherwise have maintained would be lost to the environment in a fraction of a picosecond.
Personally, I’d never subscribed to Penrose’s theory that quantum effects might play a role in consciousness; calculations dating back to a seminal paper by Max Tegmark, twenty years before, had already made sustained coherence in any neural structure extremely unlikely. Nevertheless, it had taken considerable ingenuity on the part of Olivia and her team to rule out the idea definitively, in a series of clear-cut experiments. Over the past two years, they’d chased the ghost away from each of the various structures that different factions of Penrose’s disciples had anointed as the essential quantum components of the brain. The earliest proposal — the microtubules, huge polymeric molecules that formed a kind of skeleton inside every cell — had turned out to be the hardest to target for disruption. But now it was entirely possible that the cytoskeletons of my very own neurons were dotted with molecules that coupled them strongly to a noisy microwave field in which my skull was, definitely, bathed. In which case, my microtubules had about as much chance of exploiting quantum effects as I had of playing a game of squash with a version of myself from a parallel universe.
When the experiment was over, Olivia thanked me, then became even more distant as she reviewed the data. Raj, one of her graduate students, slid out the needle and stuck a plaster over the tiny puncture wound, then helped me out of the cap.
“I know you don’t know yet if I was a control or not,” I said, “but have you noticed significant differences, with anyone?” I was almost the last subject in the microtubule trials; any effect should have shown up by now.
Olivia smiled enigmatically. “You’ll just have to wait for publication.” Raj leant down and whispered, “No, never.”
I climbed off the couch. “The zombie walks!” Raj declaimed. I lunged hungrily for his brain; he ducked away, laughing, while Olivia watched us with an expression of pained indulgence. Die-hard members of the Penrose camp claimed that Olivia’s experiments proved nothing, because even if people behaved identically while all quantum effects were ruled out, they could be doing this as mere automata, totally devoid of consciousness. When Olivia had offered to let her chief detractor experience coherence disruption for himself, he’d replied that this would be no more persuasive, because memories laid down while you were a zombie would be indistinguishable from ordinary memories, so that looking back on the experience, you’d notice nothing unusual.
This was sheer desperation; you might as well assert that everyone in the world but yourself was a zombie, and you were one, too, every second Tuesday. As the experiments were repeated by other groups around the world, those people who’d backed the Penrose theory as a scientific hypothesis, rather than adopting it as a kind of mystical dogma, would gradually accept that it had been refuted.
· · · · ·
I left the neuroscience building and walked across the campus, back towards my office in the physics department. It was a mild, clear spring morning, with students out lying on the grass, dozing off with books balanced over their faces like tents. There were still some advantages to reading from old-fashioned sheaves of e-paper. I’d only had my own eyes chipped the year before, and though I’d adapted to the technology easily enough, I still found it disconcerting to wake on a Sunday morning to find Francine reading the Herald beside me with her eyes shut.
Olivia’s results didn’t surprise me, but it was satisfying to have the matter resolved once and for all: consciousness was a purely classical phenomenon. Among other things, this meant that there was no compelling reason to believe that software running on a classical computer could not be conscious. Of course, everything in the universe obeyed quantum mechanics at some level, but Paul Benioff, one of the pioneers of quantum computing, had shown back in the ’80s that you could build a classical Turing machine from quantum mechanical parts, and over the last few years, in my spare time, I’d studied the branch of quantum computing theory that concerned itself with avoiding quantum effects.
Back in my office, I summoned up a schematic of the device I called the Qusp: the quantum singleton processor. The Qusp would employ all the techniques designed to shield the latest generation of quantum computers from entanglement with their environment, but it would use them to a very different end. A quantum computer was shielded so it could perform a multitude of parallel calculations, without each one spawning a separate history of its own, in which only one answer was accessible. The Qusp would perform just a single calculation at a time, but on its way to the unique result it would be able to pass safely through superpositions that included any number of alternatives, without those alternatives being made real. Cut off from the outside world during each computational step, it would keep its temporary quantum ambivalence as private and inconsequential as a daydream, never being forced to act out every possibility it dared to entertain.
The Qusp would still need to interact with its environment whenever it gathered data about the world, and that interaction would inevitably split it into different versions. If you attached a camera to the Qusp and pointed it at an ordinary object — a rock, a plant, a bird — that object could hardly be expected to possess a single classical history, and so neither would the combined system of Qusp plus rock, Qusp plus plant, Qusp plus bird.
The Qusp itself, though, would never initiate the split. In a given set of circumstances, it would only ever produce a single response. An AI running on the Qusp could make its decisions as whimsically, or with as much weighty deliberation as it liked, but for each distinct scenario it confronted, in the end it would only make one choice, only follow one course of action.
I closed the file, and the image vanished from my retinas. For all the work I’d put into the design, I’d made no effort to build the thing. I’d been using it as little more than a talisman: whenever I found myself picturing my life as a tranquil dwelling built over a slaughter house, I’d summon up the Qusp as a symbol of hope. It was proof of a possibility, and a possibility was all it took. Nothing in the laws of physics could prevent a small portion of humanity’s descendants from escaping their ancestors’ dissipation.
Yet I’d shied away from any attempt to see that promise fulfilled, firsthand. In part, I’d been afraid of delving too deeply and uncovering a flaw in the Qusp’s design, robbing myself of the one crutch that kept me standing when the horror swept over me. It had also been a matter of guilt: I’d been the one granted happiness, so many times, that it had seemed unconscionable to aspire to that state yet again. I’d knocked so many of my hapless cousins out of the ring, it was time I threw a fight and let the prize go to my opponent instead.
That last excuse was idiotic. The stronger my determination to build the Qusp, the more branches there would be in which it was real. Weakening my resolve was not an act of charity, surrendering the benefits to someone else; it merely impoverished every future version of me, and everyone they touched.
I did have a third excuse. It was time I dealt with that one, too.
I called Francine.
“Are you free for lunch?” I asked. She hesitated; there was always work she could be doing. “To discuss the Cauchy-Riemann equations?” I suggested.
She smiled. It was our code, when the request was a special one. “All right. One o’clock?”
I nodded. “I’ll see you then.”
· · · · ·
Francine was twenty minutes late, but that was less of a wait than I was used to. She’d been appointed deputy head of the mathematics department eighteen months before, and she still had some teaching duties as well as all the new administrative work. Over the last eight years, I’d had a dozen short-term contracts with various bodies — government departments, corporations, NGOs — before finally ending up as a very lowly member of the physics department at our alma mater. I did envy her the prestige and security of her job, but I’d been happy with most of the work I’d done, even if it had been too scattered between disciplines to contribute to anything like a traditional career path.
I’d bought Francine a plate of cheese-and-salad sandwiches, and she attacked them hungrily as soon as she sat down. I said, “I’ve got ten minutes at the most, haven’t I?”
She covered her mouth with her hand and replied defensively, “It could have waited until tonight, couldn’t it?”
“Sometimes I can’t put things off. I have to act while I still have the courage.”
At this ominous prelude she chewed more slowly. “You did the second stage of Olivia’s experiment this morning, didn’t you?”
“Yeah.” I’d discussed the whole procedure with her before I volunteered.
“So I take it you didn’t lose consciousness, when your neurons became marginally more classical than usual?” She sipped chocolate milk through a straw.
“No. Apparently no one ever loses anything. That’s not official yet, but — ”
Francine nodded, unsurprised. We shared the same position on the Penrose theory; there was no need to discuss it again now.
I said, “I want to know if you’re going to have the operation.”
She continued drinking for a few more seconds, then released the straw and wiped her upper lip with her thumb, unnecessarily. “You want me to make up my mind about that, here and now?”
“No.” The damage to her uterus from the miscarriage could be repaired; we’d been discussing the possibility for almost five years. We’d both had comprehensive chelation therapy to remove any trace of U-238. We could have children in the usual way with a reasonable degree of safety, if that was what we wanted. “But if you’ve already decided, I want you to tell me now.”
Francine looked wounded. “That’s unfair.”
“What is? Implying that you might not have told me, the instant you decided?”
“No. Implying that it’s all in my hands.”
I said, “I’m not washing my hands of the decision. You know how I feel. But you know I’d back you all the way, if you said you wanted to carry a child.” I believed I would have. Maybe it was a form of doublethink, but I couldn’t treat the birth of one more ordinary child as some kind of atrocity, and refuse to be a part of it.
“Fine. But what will you do if I don’t?” She examined my face calmly. I think she already knew, but she wanted me to spell it out.
“We could always adopt,” I observed casually.
“Yes, we could do that.” She smiled slightly; she knew that made me lose my ability to bluff, even faster than when she stared me down.
I stopped pretending that there was any mystery left; she’d seen right through me from the start. I said, “I just don’t want to do this, then discover that it makes you feel that you’ve been cheated out of what you really wanted.”
“It wouldn’t,” she insisted. “It wouldn’t rule out anything. We could still have a natural child as well.”
“Not as easily.” This would not be like merely having workaholic parents, or an ordinary brother or sister to compete with for attention.
“You only want to do this if I can promise you that it’s the only child we’d ever have?” Francine shook her head. “I’m not going to promise that. I don’t intend having the operation any time soon, but I’m not going to swear that I won’t change my mind. Nor am I going to swear that if we do this it will make no difference to what happens later. It will be a factor. How could it not be? But it won’t be enough to rule anything in or out.”
I looked away, across the rows of tables, at all the students wrapped up in their own concerns. She was right; I was being unreasonable. I’d wanted this to be a choice with no possible downside, a way of making the best of our situation, but no one could guarantee that. It would be a gamble, like everything else.
I turned back to Francine.
“All right; I’ll stop trying to pin you down. What I want to do right now is go ahead and build the Qusp. And when it’s finished, if we’re certain we can trust it … I want us to raise a child with it. I want us to raise an AI.”
2029
I met Francine at the airport, and we drove across São Paulo through curtains of wild, lashing rain. I was amazed that her plane hadn’t been diverted; a tropical storm had just hit the coast, halfway between us and Rio.
“So much for giving you a tour of the city,” I lamented. Through the windscreen, our actual surroundings were all but invisible; the bright overlay we both perceived, surreally coloured and detailed, made the experience rather like perusing a 3D map while trapped in a car wash.
Francine was pensive, or tired from the flight. I found it hard to think of San Francisco as remote when the time difference was so small, and even when I’d made the journey north to visit her, it had been nothing compared to all the ocean-spanning marathons I’d sat through in the past.
We both had an early night. The next morning, Francine accompanied me to my cluttered workroom in the basement of the university’s engineering department. I’d been chasing grants and collaborators around the world, like a child on a treasure hunt, slowly piecing together a device that few of my colleagues believed was worth creating for its own sake. Fortunately, I’d managed to find pretexts — or even genuine spin-offs — for almost every stage of the work. Quantum computing, per se, had become bogged down in recent years, stymied by both a shortage of practical algorithms and a limit to the complexity of superpositions that could be sustained. The Qusp had nudged the technological envelope in some promising directions, without making any truly exorbitant demands; the states it juggled were relatively simple, and they only needed to be kept isolated for milliseconds at a time.
I introduced Carlos, Maria and Jun, but then they made themselves scarce as I showed Francine around. We still had a demonstration of the “balanced decoupling” principle set up on a bench, for the tour by one of our corporate donors the week before. What caused an imperfectly shielded quantum computer to decohere was the fact that each possible state of the device affected its environment slightly differently. The shielding itself could always be improved, but Carlos’s group had perfected a way to buy a little more protection by sheer deviousness. In the demonstration rig, the flow of energy through the device remained absolutely constant whatever state it was in, because any drop in power consumption by the main set of quantum gates was compensated for by a rise in a set of balancing gates, and vice versa. This gave the environment one less clue by which to discern internal differences in the processor, and to tear any superposition apart into mutually disconnected branches.
Francine knew all the theory backwards, but she’d never seen this hardware in action. When I invited her to twiddle the controls, she took to the rig like a child with a game console.
“You really should have joined the team,” I said.
“Maybe I did,” she countered. “In another branch.”
She’d moved from UNSW to Berkeley two years before, not long after I’d moved from Delft to São Paulo; it was the closest suitable position she could find. At the time, I’d resented the fact that she’d refused to compromise and work remotely; with only five hours’ difference, teaching at Berkeley from São Paulo would not have been impossible. In the end, though, I’d accepted the fact that she’d wanted to keep on testing me, testing both of us. If we weren’t strong enough to stay together through the trials of a prolonged physical separation — or if I was not sufficiently committed to the project to endure whatever sacrifices it entailed — she did not want us proceeding to the next stage.
