The Year's Best Science Fiction, Vol. 20

Isabelle called out, “Marco! Sophie!” as we followed her through the door. At the end of the hall, I heard childish giggling, and an adult male voice whispering in French. Then Isabelle’s husband stepped out from behind the corner, a smiling, dark-haired young man, with Sophie riding on his shoulders. At first I couldn’t look at her; I just smiled politely back at Marco, while noting glumly that he was at least 15 years younger than I was. How could I even think of doing this, at 46? Then I glanced up, and caught Sophie’s eye. She gazed straight back at me for a moment, appearing curious and composed, but then a fit of shyness struck her, and she buried her face in Marco’s hair.

Isabelle introduced us, in English; Sophie was being raised to speak four languages, though in Switzerland that was hardly phenomenal. Sophie said, “Hello” but kept her eyes lowered. Isabelle said, “Come into the living room. Would you like something to drink?”

The five of us sipped lemonade, and the adults made polite, superficial conversation. Sophie sat on Marco’s knees, squirming restlessly, sneaking glances at us. She looked exactly like an ordinary, slightly gawky, six-year-old girl. She had Isabelle’s straw-coloured hair, and Marco’s brown eyes; whether by fiat or rigorous genetic simulation, she could have passed for their biological daughter. I’d read technical specifications describing her body, and seen an earlier version in action on the video, but the fact that it looked so plausible was the least of its designers’ achievements. Watching her drinking, wriggling and fidgeting, I had no doubt that she felt herself inhabiting this skin, as much as I did my own. She was not a puppeteer posing as a child, pulling electronic strings from some dark cavern in her skull.

“Do you like lemonade?” I asked her.

She stared at me for a moment, as if wondering whether she should be affronted by the presumptuousness of this question, then replied, “It tickles.”

In the taxi to the hotel, Francine held my hand tightly.

“Are you OK?” I asked.

“Yes, of course.”

In the elevator, she started crying. I wrapped my arms around her.

“She would have been 20 this year.”

“I know.”

“Do you think she’s alive, somewhere?”

“I don’t know. I don’t know if that’s a good way to think about it.”

Francine wiped her eyes. “No. This will be her. That’s the way to see it. This will be my girl. Just a few years late.”

Before flying home, we visited a small pathology lab, and left samples of our blood.

Our daughter’s first five bodies reached us a month before her birth. I unpacked all five, and laid them out in a row on the living room floor. With their muscles slack and their eyes rolled up, they looked more like tragic mummies than sleeping infants. I dismissed that grisly image; better to think of them as suits of clothes. The only difference was that we hadn’t bought pyjamas quite so far ahead.

From wrinkled pink newborn to chubby 18-month-old, the progression made an eerie sight-even if an organic child’s development, short of serious disease or malnourishment, would have been scarcely less predictable. A colleague of Francine’s had lectured me a few weeks before about the terrible “mechanical determinism” we’d be imposing on our child, and though his arguments had been philosophically naпve, this sequence of immutable snapshots from the future still gave me goose bumps.

The truth was, reality as a whole was deterministic, whether you had a Qusp for a brain or not; the quantum state of the multiverse at any moment determined the entire future. Personal experience-confined to one branch at a time-certainly appeared probabilistic, because there was no way to predict which local future you’d experience when a branch split, but the reason it was impossible to know that in advance was because the real answer was “all of them.”

For a singleton, the only difference was that branches never split on the basis of your personal decisions. The world at large would continue to look probabilistic, but every choice you made was entirely determined by who you were and the situation you faced.

What more could anyone hope for? It was not as if who you were could be boiled down to some crude genetic or sociological profile; every shadow you’d seen on the ceiling at night, every cloud you’d watched drift across the sky, would have left some small imprint on the shape of your mind. Those events were fully determined too, when viewed across the multiverse-with different versions of you witnessing every possibility-but in practical terms, the bottom line was that no private investigator armed with your genome and a potted biography could plot your every move in advance.