Single-Bit Error

by Ken Liu

Before he met Lydia, Tyler’s life, like the lives of most people, involved the steady accretion of names:

— “What happened next?” “Nothing,” Grandmother said. “They just lived happily ever after.” “Forever?” “Forever.”

Until Grandmother read him “Sleeping Beauty,” Tyler thought every story ended the way his parents ended them: “And they lived, sometimes even happily, until the day they died.”

— Tyler and every other kid avoided the new boy because he was bigger than all of them and stared at everyone like he was looking for a fight. But the only empty seat in Mrs. Younge’s Art class that day was next to Tyler, and that was how Owen Last and Tyler became best friends.

— Tyler looked at her until the music stopped. He was just about to ask her to dance when her date showed up. “So it is possible to fall in love in half an hour,” he thought. He wrote “Amber Ria” on a slip of paper and sealed it in a beer bottle with aluminum foil and threw the bottle as far into Long Island Sound as he could.

— Whenever somebody said “Tyler” they both looked up. But then the thin boy with a scar on his chin stopped coming to class and Tyler never found out what his last name was.

— San Francisco was just a dot on the map until he saw the seals sunbathing by Fisherman’s Wharf.

— At the coffee house open mike, he read a poem called “Allure, Obsession, Desire and Devotion.” Tyler could not understand why all the women were laughing until the woman sitting behind Owen showed him the perfume advertisements in the magazine in her hand. Lena Lyman and Tyler dated for exactly two months. Her favorite scent was Envy.

— Tyler didn’t know what that bright star in the sky was called until he moved into his new apartment and found an abandoned star atlas in the kitchen, next to a bowl of fresh clementines. He tasted sweetness on his tongue whenever he thought about Sirius, the Dog Star.

The first time Tyler saw her was in a dumpster behind the Wholly Place two blocks from his apartment. He had gone around the back of the store to look for some empty boxes to carry his organic potatoes and free range chicken breasts home (the Wholly Place believed in neither paper nor plastic).

She was standing up in the dumpster, her hands lifting into the sun a giant jar of olives that had just passed their expiration date. A dark blue cotton tank top showed off the creases and dimples on her elbows. Her sun-bleached, ginger-red hair was pinned into lopsided coils on top of her head with a black barrette. A scattering of freckles gave color and vibrancy to her pale face.

She turned to him, putting the jar of olives down on top of the pile of other things she had fished out of the dumpster. She had chapped lips, the sort of lips that came from smoking cigarettes and laughing at statistics. Her eyes were the color of moth wings. She’s going to smile, he knew, and he wanted to know if her teeth were white and crooked.

Tyler thought she was the most beautiful woman he had ever seen.

“You know that most of the stuff they throw out here is still good for at least another week, right?” She beckoned him closer. “Come and give me a hand.”

Yes, she was smiling.

We think we know a few things about the way memory works. We think that memories of things that actually happened, such as what you ate for dinner, things that could have happened but didn’t, such as the smart retort that came to mind too late, and things that simply could not have happened, such as the way sunlight might reflect from an angel’s eyes, are encoded the same way at the level of neurons. To distinguish between them requires logic and reason, and a level of indirection. This is troublesome to some people in so far as they believe that our construction of reality is based on memories. If you cannot tell these kinds of memories apart, then it seems that you can be made to believe anything.

The consolation of philosophy and religion both was that they helped men classify the types of memories and keep their hold on the fragile authenticity of their waking lives.

When Tyler was very young, his grandmother was his favorite person in the world because, unlike his parents, who believed that children should always be told the truth as adults understood it, she would fill in the gaps in his knowledge — Santa Claus, the Easter Bunny, God. His parents were always too busy and often a little too serious, but his grandmother had a sense of peace about her, a lightness that lifted his spirit. A few times, when Tyler’s parents were away, she took him with her to church. He remembered liking the singing and the colorful windows, and how safe he felt there, in that large, empty space, sitting on a hard bench next to her warmth.

When she died, grief overwhelmed Tyler. But like most adults, when he grew older he could only recall the intensity of that love in childhood in an abstract way. He made the common error of identifying maturity with worth, and assumed that the love he had for her as a young child must have been lacking in strength and depth.

For many years after her death, however, Tyler was tortured by the memory of a certain visit from her. He was five or so, and they were playing some board game at the kitchen table. As he swung his legs in his excitement, he kicked her repeatedly in the shins. She asked him to stop, and he refused, giggling. When she finally frowned at him and threatened to stop playing if he didn’t stop he told her to go to Hell.

In Tyler’s mind he could see her face grow taut, lose color, and then, for the only time he could remember, she began to cry. He also remembered his own utter confusion. His parents did not have much use for religion and so for him Hell was a word without much mystery or power. At that time he knew only vaguely that Hell was a place you did not want to go, like the dark basement or the even darker attic. He remembered feeling resentful that she was crying and he did not even understand why.

Tyler felt the guilt of this memory even in his teenage years. For him it summed up all his insecurities and fears about his own cruelty, ignorance, and the possibility that he was, in reality, not a good person. The fact that he had caused someone who loved him such pain with so little effort and understanding troubled him deeply.

One day Tyler looked through an old family photo album, and in it was a picture of the kitchen in the house they used to live in. He was surprised to discover that the small kitchen contained a central island, and had no space for the table in his memory at all.

The memory that had caused him such pain over the years could not possibly have occurred.

With the discovery of that single error in his memory came a cascade of other revelations. Now he remembered that they always ate in the dining room, and when they did play board games, it was always on the coffee table in the living room. The memory that had caused him such pain over the years could not possibly have occurred. Somehow, he must have manufactured the whole scene in his imagination.

It was not very hard to explain what really happened, he thought. The death of his grandmother had probably caused in him feelings of abandonment and guilt. In his confusion he had taken elements from storybooks and imagined out of nothing this memory to punish himself. This was the sort of fantasy that could have occurred to any young child who lost an important relative. With that realization, the image of his grandmother crying faded in his memory and became less and less believable.

Tyler thought he was very lucky to have discovered the single error in his false memory, which enabled him to reason his way into distinguishing between reality and fantasy. He felt that it was a coming-of-age moment.

Nonetheless, he admitted to himself that he was a little sad also at the discovery. For however imaginary that memory was, it was also a part of his love for his grandmother. When that memory lost its compelling aura of truth, it was like another part of her died with it. He had no name for the emptiness that remained.

The best pistachio ice cream in the world was served in Dora’s Ice Cream Parlor in the town of Los Aldamas. Tyler knew this because it was while they were there, with the air conditioner cooling the back of his neck and the sunlight streaming in through the cracks in the dusty windowpanes, while they shared a small cup of pistachio ice cream, that Lydia said to him, “Yes, of course I will. Let’s.”

A month earlier he had helped her carry the olives and bread and grape juice she had salvaged from the Wholly Place dumpster to her apartment, which turned out to be in the same building as his, only on the floor below. What little furniture there was in the apartment was made from cardboard boxes with sheets draped over them. It was like being on the set of a minimalist play.

Lydia spread a blanket on the floor and they had a picnic in the middle of the afternoon in her twelve-by-ten studio. She broke the bread into pieces and handed the pieces to him, and they drank the grape juice from the bottle.

“The Eucharist,” Lydia said, “à la Lydia.” She said it with the same tone one would say, “Pollo Calabrese, my grandmother’s recipe.” It didn’t sound like a joke. She offered him an olive from the jar.

It had been many years since Tyler had last gone to a church with his grandmother, and he didn’t know what to say. But he wanted to stay with her and look at her face, which, though it broke into smiles only occasionally, was suffused with a happiness that Tyler felt as a wave of heat.

He told her about his job as a database programmer at a bank, and about his nights scribbling in his notebook and reading in smoke-filled coffee houses to other young men and women with dreams like his own. He told her a selection of the most important names of his life and the stories behind them. While he spoke, he marveled at her face, and how he was already crazy about her.

Tyler asked her questions. He wanted to know the life of the woman he was falling in love with, to understand her collection of names.

Lydia had grown up in New Camden, one of thousands of other towns just like it, exurbs cast adrift along the highways between Boston and New York. She was named in honor of a grandmother who died before she was born. When she was little her mother called her “Peapod” because she was chubby and loved the sun. Her father called her “Princess” because that was what he thought all fathers called their daughters.

For much of junior high she did not know who she was. Her parents fought and when they finally stopped fighting her father wanted her to continue to be called Lydia Getty, and her mother wanted her to be called Lydia O’Scannlain. She spent her summers at her father’s new home in Arizona, where he took her to meet his friends at night. They called her “Baby Shark” because she beat them at poker. At school the girls called her Lydia O’Hara because her favorite color was red. The boys did not have a name for her because, as far as they knew, she had not yet kissed anyone.

In high school she was Lydia the Pothead, and she was popular with the boys for all the wrong reasons. Her mother called her names that she would rather not remember. Once a boy drove her to a building in Boston, where angry men and women waving signs and placards lined the driveway as she walked up, alone, and called her names that made her shiver. Later, as she lay in a small white room, recovering, a nurse told her to ignore the noises outside and to try to imagine herself as A Very Brave Young Woman.

She fell asleep, and was startled awake when she felt the room shake. Her life was transformed at that moment because she was visited by the angel Ambriel, the angel with eyes the color of moth wings.

Contrary to most accounts of angelic visitations — Lydia told Tyler, who did not yet quite understand what he was hearing — angels do not engage in conversation with the visited. The power of the visitation comes entirely from the presence of the angel itself, which is a fragment of the being of God.

Like that of millions of other people, Lydia’s life, though not filled with extraordinary suffering, had had enough disappointments and betrayals by that point that she had lost what little faith the church had been able to instill in her. God had the same status in reality as neutrinos.

Now, Lydia looked upon the angel, and felt Ambriel’s light punch through her eyes and fill her mind, and the pain was so glorious that she could not even conceive of closing her eyes. Everything she had ever learned about anything was simply wrong, irrelevant. Ambriel’s light illuminated the deafening silences between her parents, the old and fresh scars from that zero-sum game known as social life in a high school, the humble, confusing and desperate inconsistencies of an ordinary life. In that light, all of it was coherent, sensible, and above all, beautiful.

In that moment Lydia was made anew. She was filled with such love for God that she finally understood why Hell is really the absence of God, and has nothing to do with fire or brimstone.

Tyler learned then what it was he saw in Lydia’s face that so pulled at his heart. He saw in that face the signs of that species of happiness we used to call blessed. To be blessed is to be without fear, which is just another name for desire left unfulfilled. But the very presence of God, even through the intermediary of an angel, made unfulfilled desires meaningless for her. The only fear left after a visitation was the fear that one might be denied the presence of God. But since the only requirement to reach God is to love Him, and it is not possible to not love Him after having experienced the joy of His presence, Lydia’s salvation was guaranteed.

At that moment, Lydia learned who she was. She was one of the Saved. This did not mean that she had to give up drugs and swearing, or that she had to put on a white robe and roam the streets stuffing pamphlets under people’s doors. It simply meant that she could now go on with her life and everything she did in the future would be full of joy because she loved God.

And so Tyler was in love with Lydia because God’s light, dim though it was by the time it was refracted through Lydia onto him, nevertheless dazzled him.

He took Lydia with him to poetry readings, where Lydia met his friends who wanted to write poetry and congregated in those smoke-filled basement cafés. When Tyler read from the cocoon of the spotlight, he sought out her luminous face and bright halo of red hair in the dim light of the café because she smiled when she heard him read and he loved to see her smile.

Because she couldn’t tell an iamb apart from the Lamb; because she smelled of soap and sunlight; because when she told him she would go look at stars with him she really meant it; because when he made fun of people who said “irregardless,” she made him look it up in a dictionary so that he learned that it really was a word; because he knew that he could always tell when she would laugh a fraction of a second before she did.

Although Tyler’s friends didn’t know quite what to say at first when they heard Lydia tell her story of her encounter with Ambriel, they soon came to like her because she was nothing like what they would have expected from someone who claimed to see angels. She could hold her drink better than any of them — even Owen, who still looked like he would rather be out on the road on a motorcycle than in an office — and she would wink at Tyler when she was drunk and whisper, “I’m dangerous, and I’ll eat you like air.”

On Sundays Lydia did not go to church. She never went to churches because they had nothing to offer her, and in any case most churches in the city were embarrassed by her story. Instead, she brought him to meetings of people who had been visited by angels and people who wanted to be visited by angels. These meetings occurred in the basements of churches and libraries, and they involved a lot of folding chairs and stale coffee, as well as a lot of desperation and phrases cribbed from the self-help aisles. Often Tyler wondered why he was in these meetings at all until he saw the light in Lydia’s face as she told her story.

On other days they wandered the streets of the city after work. They took short road trips to small towns up and down the Pacific Coast. They talked about everything and nothing at all, and all the while Tyler gazed into Lydia’s face and wanted to believe.

That month between the day he met her in a dumpster and the day she said yes, she would marry him, while feeding him pistachio ice cream was the happiest month of Tyler’s life.

The only trouble was, he still did not believe in God.

On their way back from Las Aldamas, Lydia fell asleep in the passenger seat. The road was straight and smooth, and the traffic was light. Tyler put the car on cruise control and stretched his legs. He reached for Lydia’s hand and turned his head to glance at her sleeping form.

Later, when Tyler tried to recall what he felt, as he watched Lydia slowly die in the seat next to him, her body upside down and held in place by the seatbelt, her back twisted at an impossible angle, the collapsed roof of the car trapping her arms, he was surprised to find that he could recall no pain from his own body at all.

But that could not have been the case. Both his legs were broken, and the heat from the flames must have been intense on his side of the wreckage, judging by the burns covering his face and arms. When he finally recovered enough to sit up on his own in the hospital, he also found that the blindness in his left eye would be permanent.

Be that as it may, the fact was that all Tyler could remember was how calm and unafraid Lydia was as she told him that she knew she was going to die, that she was not in any pain, and that she would see him in Heaven.

Then her eyes got wide, and she said, “Hello, Ambriel.”

Tyler tried to twist around in his seat so he could see what she was seeing, even though he knew that he would see nothing. The steering wheel got in his way and he gave up after a few seconds. He would regret those few seconds later because he took his eyes off Lydia’s face, and during those few seconds she died.

If Tyler were religious, he could have been comforted by the promise of reuniting with Lydia in Heaven. Or he could have been angry with God, and railed against Him until he could come to accept his life the way Job accepted his. But Tyler did not believe in Heaven or God.

But neither could his lack of faith give him comfort, for he loved Lydia for that light in her, and he had no name or explanation for that light except what Lydia told him. Her faith was what he loved.

To continue in his lack of faith would be to assert that Lydia’s joy was an illusion, and that would kill the very heart of his memory of her. But to believe would require him to break down the barriers between fantasy and reality in his mind and embrace as fact what seemed to him a hallucination. While Lydia was alive he could delay that decision for as long as he was in love, but her death meant that he had to choose.

When Tyler finally got out of the hospital, he locked himself away from his friends. He quit his job and he unplugged his phone.

What he did was to find out everything he could about the accident, and to try to understand what happened. This was difficult because there was little the investigators could find out, and there were many blanks to be filled in. But Tyler had lots of time.

Much of a programmer’s job — Tyler read — consists of untangling the web of links bridging the level of indirection between variables and values.

Variables are the electronic memory equivalents of names. Instead of working with individual bytes, a block of memory can be given a name with a variable. Variables can be made to name anything: throttle settings, social security numbers, a subroutine to wipe the disk.

Unfortunately, there is no way to tell if a variable is pointing at what it claims to be pointing at, or if it’s pointing at anything at all. At the level of bits, the number of butterflies in Costa Rica looks just like the velocity of the tropical storm off the coast of Australia.

This is troublesome to every programmer because the correspondence between variables and values lies at the foundation of any program’s tenuous claim to correctness. If you can convince the computer that a variable names something real when it really points into the void, all bets are off.

In order to help programmers maintain the distinction between solid reality and fantastic disaster, type systems were introduced. These were mathematical constructs embodied in programming languages to ensure that a variable meant for the throttle setting would not point to, say, the current acceleration of the car. Type systems imposed the consolation of infallible order against the madness of an amoral sea of bits.

Like many other modern cruise control systems, the one in Tyler’s car relied upon a microcomputer running a dedicated program.

Obviously it was very important that this program did its job correctly. The program in Tyler’s car was written by a careful programmer who understood that lives depended on him getting it right. But more than that, the program was written in a language that had a very strong type system. There was a mathematical proof showing that no matter how clever or careless a programmer was, a program that passed the type-checking would be guaranteed to never allow a variable declared to point at the fuel level to point at the subroutine for shifting gears. This was as close to infallibility as you could get in the world of bits.

All this is to say that Tyler had good reason to relax and lean back in his seat.

About two thousand years earlier — Tyler read some more — around the time of Christ, there was a star in the region of the sky dominated by the constellation Cassiopeia. The star was old and dying, and one winter night, it went supernova.

Out of this explosion emerged countless protons and neutrons traveling away from the wreckage of the old star at great speed. They are called cosmic rays, and most of them will go on hurling through the void of space till the end of time, and their fates need not concern us.

But one proton in particular arrived on Earth that sunny July day after traveling through the dark for two thousand years. It plunged through the ionosphere, gracefully dodging the lines of the Earth’s magnetic field, and then straight through the thickening air, barely slowing down. It would have gone on and sunk itself straight into the California desert on that day, but something got in the way.

At that moment, Lydia was asleep and Tyler had his eyes off the road for a moment to look at her. Even in sleep, her face held that blessed quality of light. And their car intercepted the path of the lone escaped proton from that long ago death of a star.

The proton paid little attention to the metal casing and the plastic polymers interested it even less. It ripped right through them and, for a moment, it looked as if it would go on with its journey. It seemed that way until the proton came upon an infinitesimal bit of silicon, and for the first time in two thousand years, it took an interest in tangible matter and decided to knock the electrons out of it.

That bit of silicon happened to be a part of a capacitor. There were millions of other capacitors and transistors just like it, all of them parts of the integrated circuit that made up the memory of the computer running the program controlling Tyler’s car. The absence of those electrons was an insignificant anonymity by any measure in the scheme of things, but it was enough.

The loss of those electrons meant that the bit that used to represent a 1 would now be interpreted as a 0, and that bit happened to be located inside a memory cell that held a variable. The flip in that bit meant that the variable, which was supposed to give the address of the subroutine for computing throttle settings, was now pointing at the value for the fuel flow rate, 1024 bytes away from where the variable was supposed to be pointing.

The type system of the language in which the program was written was designed to prevent just this sort of violation. A variable meant to point to a subroutine should never have been able to point at numerical data. Once that had happened, anything else was possible.

If a single-bit error on a circuit board could breach the mathematically perfect type system of a programming language, Tyler reasoned, wasn’t it conceivable that a single-bit error in the brain could break down the system of distinctions between nurses and angels? All it would take was for one neural connection to be broken and randomly reattached somewhere else, somewhere it had no business to be connected to, and all the walls between the types of memories would come crumbling down.

Lydia’s vision of Ambriel, and indeed her faith, was then simply the consequence of a misfiring of the neurons, a misfiring that could have been triggered by fatigue, by stress, by a stray elementary particle, indeed, by anything at all, on that long ago day in the clinic in Boston. It was really the same process that had conjured up his memory of making his grandmother cry.

In order to reason your way to faith, Tyler thought, all you needed was a single-bit error.

The technically proficient could breach the best software security systems by deliberately inducing errors in the hardware. Couldn’t the rational induce faith in themselves the same way?

Contrary to what you might expect, this theory did not cheapen or degrade Lydia’s faith in Tyler’s mind. For this explanation allowed Tyler to understand, rationally, Lydia’s life. Calling Lydia’s faith an error was a level of indirection that bridged the gap between their worlds.

Moreover, errors, once understood, could be induced. The technically proficient could breach the best software security systems by deliberately inducing errors in the hardware. Couldn’t the rational induce faith in themselves the same way?

Tyler decided that he would try to induce a single-bit error in his own brain. If the only way for him to meet Lydia was to go to Heaven, then rationally, he had no choice but to make himself believe in God.

One possibility was to weaken the body. Starvation, dehydration, exposure to the elements. Errors were more likely when the body’s defenses were down. This was the path of the mystics of the desert. Tyler decided that he would try that first.

He drove the rental car south and then east until he was in Arizona, close to the border with Mexico, the edge and then the heart of the Sonoran Desert. He drove until the roads were no longer roads and then he walked. He walked until he decided he could no longer find his way back, and then he walked some more. Eventually he found himself surrounded on all sides by clumps of saguaro cactus. He was very hungry and thirsty by then, so he sat down and waited for his body to fail.

“Don’t take this the wrong way,” Owen had said to him before he left. “But I used to think that you were never going to make it as a poet. I thought you didn’t have enough imagination. And now I think you have too much.”

Tyler had not seen Owen for a few weeks while he was locked in his own apartment trying to understand Lydia’s death. They were sitting in their favorite coffee shop, and it was raining outside, a rare autumn shower.

“Programmers are not really numbers people,” Tyler said. “We are words people. The numbers people work in hardware.”

“It won’t be like real faith,” Owen said, instead of telling him to stop acting crazy and get on with his life. Tyler appreciated that. “Even if it works. Even if you get visions of angels singing hosannas.”

“How do you know what real faith is like? You don’t believe in God either.”

“I don’t need to believe in God to tell you that you’re going to fail. You want to believe in God because you love Lydia. But you’ve already decided that believing in God is an error, a mistake, without ever having experienced it. You want to force yourself to accept as true what you have already decided to be a lie. That’s a gulf that cannot be bridged.”

“You have not worked through the logic,” Tyler said. “What good is a rational explanation for faith if I do not test the hypothesis?”

Owen shook his head. “Some things cannot bear to be directly examined. If you are looking for a faint star, you will not see it if you look directly at where it is. You have to look to the side, and let it catch your eye unawares.”

“A level of indirection then,” Tyler said to the saguaro cactus beside him, and he began to laugh. How long had he been sitting in the desert? It seemed like days. Night was coming. It was going to be cold.

“You always think too hard,” the cactus said.

“Lydia, is that you?” This is a good sign, Tyler thought. Auditory hallucinations always came first, didn’t they? But the voice didn’t really sound like Lydia. It was too distant and too fine, like a glass harmonica. He looked around for an angel.

“So you think my brain was broken? A missed connection, that’s all it was?” The cactus said.

“No, not broken.” That was the wrong name for it. That was the problem. He needed the right name.

He wanted to tell her all about variables and single-bit errors and the type system of memories. He wanted to explain to her how he wanted to experience what she did so he could be with her. But he was very hungry and thirsty, and he felt dizzy. So all he said was, “I miss you.”

Bright lights were approaching him in the dark. He waited for the feeling of being pierced by the light, of being overwhelmed by the certainty that it was all going to be okay, of love, of being saved. He waited for the walls in his mind to collapse.

The light stopped in front of him. Several figures appeared in the light. Their hair were halos of light and their bodies were limned in fire. He was a little surprised that the light was not as bright as he had expected. It was painful to look into the light, but not like Lydia had described it. Which angels are these?

“Maybe it’s because I have only one eye now,” he said to himself.

“It’s okay now,” Owen said. “Everything is going to be all right.”

They carried him into the back of the ranger’s car and began the long drive back.

He tried drugs, but the effects were not permanent. Meditation just made him tired. He read up on electroshock therapy, but no psychiatrist would agree to his demands. “You don’t need therapy,” they told him. “Go home and read the Bible. Besides, I would lose my license.”

He even went to the churches. But their faith seemed empty to him. He felt nothing sitting in the pews, mouthing the words to the hymns, listening to sermons that seemed devoid of meaning.

I want to believe, and I can’t. He looked around; no one had the kind of light in their faces that he had seen in Lydia. You think you believe, but you don’t. Not really, not like Lydia.

Owen never said, “I told you so.”

Eventually Owen managed to convince him to come out again to the cafés at night. He thought the poems being read were wretched. Why wasn’t anyone writing about the lack of that light? Why wasn’t anyone writing about the persistence of memory or the type system that was at the same time so fragile and so difficult to breach? Why wasn’t anyone writing about the pain that came from not being able to believe?

He got a new job programming databases at a bank, and he started to write again. He even managed to get some of his poems published. His friends took him out to celebrate. He was excited and happy, and a girl who looked nothing like Lydia took him home, despite the scars on his face.

“What’s your name?” he said.

“Stephanie,” she said, and turned off the light. And he would always remember her as Stephanie-Who-Looked-Nothing-Like-Lydia.

He moved on.

“Would you go get Lydia for dinner?” Jess said to Tyler from the kitchen.

Tyler was cleaning up the last few paper plates and napkins and popped balloons in the living room left over from the birthday party earlier. He walked downstairs and into the garage. The garage door was open, and through it he could see Lydia lying on the front lawn, looking up at the winter evening sky.

“Hey kiddo,” he said as he walked up next to her, “time for dinner.”

“Just a couple minutes more, please?”

He lowered himself and sat on the grass next to her. “It’s getting cold. What are you waiting for?”

“I’m looking at Sirius. It’s eight-point-six light years away, so the light we are seeing now left Sirius eight years and seven months ago. I’m eight today, and Mom said I was born nine weeks premature, in the evening. I want to catch the light that left Sirius the moment I was conceived.”

“The moment you were conceived?”

“You gave me the book, remember?”

He was going to point out that although she was born in the evening it didn’t necessarily mean that she was “conceived” in the evening. Then he stopped himself. Some details could wait.

“That is worth waiting for,” he said.

They waited together, shivering a little. It was still early winter, but you could already tell that it was going to be a cold one. Tyler sometimes missed the warm California winters.

“I think I’ve figured out why my bed has so much dust under it,” Lydia said.

“Why is that?”

“I read that dust is made up from meteors burning up in the sky. Since my room is in the attic, it’s closer to the stars than the rest of the house, so it makes sense that I get more dust than you and mom.”

He looked at her, and was overwhelmed by his love for her. She was so like him, rational, clear-headed, not afraid of the facts. Her fairy tales had star dust, but not the magic kind. She did not believe in God, and he was glad of that. Like him, she would be immune to single-bit errors.

“If I have to tell the two of you to get in here one more time, no one is getting dinner tonight.”

Jess was standing in the garage door, the light from the hallway behind her made her luminous.

“Look, mom looks like an angel.” Lydia got up and ran towards the light.

Tyler stayed where he was a moment longer. He looked at Sirius, the Dog Star, and the other burning, exploding stars in the sky, all that light coming at him from different distances and therefore from different times. He realized that he was being bombarded simultaneously by protons and photons generated at the moment Lydia was conceived, at the moment Lydia, that other Lydia, had died, at the moment he was born, at the moment Saint Augustine stole his pear, and at the moment Christ was crucified. He felt a little lightheaded.

Ambriel chose that moment to visit him.

So this is what it feels like.

Tyler was filled with such love for God that he trembled. The beauty of God’s design made him weep. He understood why he met Lydia, why she had died, and why he had failed to come to Him before that moment. He yearned to feel that light forever. He longed to be in Heaven. It was the happiest moment of his life because by experiencing what Lydia did, he was finally with her. To remember what it was like when he was in love with Lydia was better even than falling in love in the first place. The type system was breaking down.

But one detail was wrong.

He remembered looking at Sirius just before Ambriel appeared. For a fraction of a second Sirius appeared to glow a little brighter, barely perceptibly. It was a very slight twinkle. It could have been anything: an atmospheric distortion, a wisp of cloud passing, a trick of the eye.

Or maybe it was a solar flare on Sirius at the moment, eight-point-seven-five years ago, when Lydia was conceived. Maybe a proton from that explosion travelled through the emptiness of space for those years, paying nary a mind to anything in its path. Wasn’t it possible that it had plunged through the earth’s ionosphere, its stratosphere, its clouds and the wings of birds? Wasn’t it possible that it finally entered Tyler’s eye on that winter evening, piercing him to the depth of his being, and, while passing by the hypothalamus, decided to knock some electrons out of it?

It was a small error, just a bit off from the usual. But it was enough. It was enough for him to tell reality apart from illusions.

As soon as he realized it, Ambriel was gone. The type system held.

Tyler knew then that he was doomed. For the rest of his life he would remember that feeling of rapture, that love for God, that sweetness of being. He had believed, even if only for a moment. He had been with Lydia, but then he had looked. And then there was the absence of God.

He would always have that moment in his memory, and he would always know it was a single-bit error that had given him the memory and then taken its reality away from him.

He lived, sometimes even happily, until the day he died.