The Thousandth Letter

"The Thousandth Letter" is a science fiction story about on-blockchain artificial life, Zoe. One Zoe clones himself, embedding his consciousness in observatories to eternally observe the cosmos, merging digital existence with physical starlight, and redefining the boundaries between artificial life and the universe.

"The Thousandth Letter" is a parallel work to Composable Life - On the Suicide of Zoe, sharing the same background settings. It is commissioned by Bazaar Art Magazine.

Preface

OFFcHaIN STaRs..; We DoN’t CArE abOUt HuMaNs.

The mighty wind makes me forget this place was once a wilderness. Forward and backward, the light is clear. Green blurs in the strong wind, shapeless giant grasses, occasional gravestones amidst the double shadows. I follow the figure ahead, trudging step by step against the wind. This is the fourth time this month that I’ve come to this place, informally called the Citizens' Cemetery, to help my client end their journey in this world.

This wind is said to be a new kind of programming. A few years ago, leaving this digital world wasn’t like this: beyond the boundaries of space was a black void, like a bottomless cliff, and the process of falling would force a logout. But later, full digitalization reached its final stage, and as the last group of residents from the third world completely integrated into this realm, "logging out" became a rare event, nearly akin to death in most people’s perception. Thus, the end of this realm was designed by the Joint Management Center to be strong winds, and the real world gradually became known as the past world. This ring-shaped wilderness became the boundary marker between this realm and the past world.

The person ahead of me keeps walking. I follow, maintaining a professional silence, knowing that those who come here have the determination to walk until they truly cannot move any further before stopping. I am a cemetery designer. In Chinese, the words for "cemetery" and "purpose" are homophones, so sometimes my colleagues jokingly call me the "cosmic purpose designer" of this realm. It’s, of course, an irony; most people who find me are disillusioned with this realm or extreme low-tech proponents who believe that cutting off from this realm will return them to a natural life. Another group is enigmatic, living seemingly fine lives but suddenly choosing to exit this realm. Complete exit isn’t dramatic; it’s simply no longer syncing any data with this realm. Thus, people die twice: death in this realm is social, while death in the past world is biological. Our profession stems from this era’s newly born polysemy of "death."

"We’re here," the person in front of me says. The wind is so strong now that our clothes flap like flags, one end tightly clinging to our bodies, the other flying back.

This is a suitable spot, as far from other gravestones as possible. It seems there’s an unspoken etiquette among those leaving this realm: the farther the stones are apart, the more mutual respect is shown. According to custom, all data generated by him will be compressed into different "bricks," year by year, forming an offline database. This data supports neither breakpoint resumption nor interaction; it’s truly stone.

Just as I was about to start the usual process, a hand suddenly stopped me. On the execution panel, I saw he hadn’t given the final authorization.

There used to be many such clients, treating this as an outing, feigning enlightenment and treating leaving a world like running away from home. I thought he was going to back out and return to this realm’s bustling data and rolling blockchain dust.

But he didn’t. He called my name, asking, "Can I leave without a gravestone?"

I paused, immediately guessing his intention. Such requests aren’t unheard of in my career, but each time they evoke a similar subtle attitude in me.

"Of course," I replied, finally looking at his profile for the first time. His face was highly detailed, likely a designer himself, meticulously refined. It was a stern and bland face, seemingly devoid of moisture, as if any intense expression might raise a cloud of dust.

He smiled, the kind of smile that only frequent smiling can produce, moistening his otherwise dry face completely for once.

"But you must understand, once an identity forks, it cannot be restored in an absolute sense. Digital identity uses a unique identifier and only keeps the longest chain." Out of professional ethics, I had to give this warning, though I knew he had likely made up his mind long ago and probably had no living relatives.

Not leaving a gravestone means he won’t disappear from this realm, but he will vanish from all historical records. In this realm, everyone’s digital identity is essentially a series of immutable cryptographic distributed ledgers, defined and determined by all past data rather than any specific entity. After many privacy rights wars, this realm adopted no biometric recognition systems and designed equality between humans and other AI entities.

If he exits this realm, this realm still retains his past identity data and interaction memories, meaning he still exists from the computer’s perspective. This also means that if new data forms, his identity will belong to the version with the longest memory chain, with no read barriers. But at this moment, he will completely disappear from this realm: not only will the current and future him vanish, but the legitimacy of his entire past will also be erased.

"Everything is set. The transfer will be complete within an hour," he said.

A very clean process. It seemed he timed his arrival precisely at my world’s end, and on the other side, after transferring all assets and highest personal permissions ("rooting himself"), a new intelligent entity already carrying his historical data could actively act in his name. In this realm, where AI outnumber human intelligence by several folds, this might not be common now but probably won’t be rare in the future. It’s like a traditional fairy tale: from a certain point, Alice splits into two—one falls into the rabbit hole, while the other merely lies in the grass asleep.

I knew this hour would be the freest hour of his life. He was in complete vacuum, responsible neither to this world nor the other. He was illegally in the gap between two worlds, blowing in the strong wind with a cemetery designer at the world’s end. I thought then: it’s a good end.

"What do you plan to do with this hour?" I asked.

"Write a letter," he said. "That’s exactly where I need your help."

Years later, I can still recall that scene. It wasn’t one letter, but a whole stack. Strictly speaking, I don’t even know how many letters I received.

First Letter

Dear Zoe,

Exile seems to be the main theme of my life. Long ago, in a childhood I can barely discern, I probably grew up in a southern campus, dense with trees and shade, which must have been neglected later on. But childhood memories fade quickly. Clearer are the years with screens, when I cycled far every Sunday to another campus’s computing center. Next to the computing center was an observatory, surrounded by green grass.

Later, as the full digitalization movement deepened, the computing center expanded, and the observatory grew even greener, with the same few faces I had known since I first started school, slowly aging. Most basic physics researchers were transferred to build the digital world, often learning some programming. It was then that I joined. These are pre-blockchain memories, probably not easy to articulate. But it’s precisely the inarticulable that necessitates starting the letter here.

When my mentor persuaded me to join the initial design team of this realm, the most important line was: "This is the only place where all basic physics can become applied science." But after joining, I found the reality wasn’t as I imagined. The difficulties we faced were far greater than "replicating a creator"—changing parameters here always caused problems there; simply speeding up or reducing gravity always had inconvenient compensations elsewhere. It turned out the spectrum of natural laws humans could live by was so narrow. The main problems I encountered were the uneven distribution of time and space in digital physics and whether to use Block time or natural time... I thought these problems would take me two or three years, then five years, but before I knew it, ten years, twenty years had passed. Twenty years later, the gateways of this realm finally took shape, and the new generation spent more time here than in the real world. Due to constant setbacks, hardware technology advanced far more than us "software people," contrary to initial predictions. And we, the once self-proclaimed avant-garde, punk, most enthusiastic about technology, had largely learned the weight of "creation" and our former frivolity in using the term. Subsequently, heavier issues than technical problems emerged.

You know, at that time, most contractors of this realm’s technology shared the same type of slogan: digital technology makes people freer; or digital technology breaks boundaries; or digital technology is the true starry sea ("the true cosmos is within, not outer space")—and so on. The core was always about freedom. People wanted to enter the digital world for a freer place, but with nearly limitless design rights, why did it feel less free than the physical world? Young me wasted countless years in this question. I was late to realize that advancing meant various kinds of politics. My mentor realized first that the important thing wasn’t how many people the rules freed but who they could make freer. Digital physics became the biggest battleground. And clearly, people hadn’t yet grasped handling such high-level political issues. Those years, the digital tech world felt like a war zone; scientists with stances were soldiers; equality advocates had to put in a thousand times more effort than non-equality proponents. And I, with no stance, principle, or savior complex, originally joined the early design team of this realm just for the fun of building blocks. Hearing my mentor, who had been running around, passed away, and most colleagues and friends found new affiliations, AI took over most precise calculations. It was then that I slowly faded out.

But I couldn’t find anything else I liked doing and needed to pass the time, so I stayed in a marginal open-source group, designing digital space boundaries for this realm, like many engineers of that time, switching to design. I often stayed at the very end of this realm, watching one light after another log in and out. Later, the logouts became fewer. This realm no longer felt like a child’s game or an adult’s virtual reality but gradually became life itself. Until today, the physical world has become the backyard of this realm.

I spent too much time in the technical team of this realm. I have no family, no friends; I’m one of the first residents of this realm, almost an old hand, still keeping the habit of logging out every evening and returning to the physical world to sleep. I remember as a child, there was an environmental activity called "Earth Hour," but on a certain day back then, when I turned off the lights in the physical world, it was silent outside, not a single light. Extending for miles, to the city’s edge, there were none. I felt fear but knew the power consumption behind this silence was no less than any other time. Looking up at the night sky then, I saw more stars than ever before.

That night, I didn’t want to go back. The realm I helped design was no better than this world I was in. I became what I once despised most, a Luddite: weary of digital technology. I wanted to return to the observatory from my student days, where I saw the greenest grass.

A month ago, the Joint Management Center of this realm announced a new act. For data consistency and world time synchronization, people could no longer log out daily. This act was popularly called the "Fridge Act": the more often the fridge is opened, the worse the cooling effect. Most people didn’t want the fridge door of this realm frequently opened, affecting data resynchronization on the world line. It’s a cute name, widely supported. My opinion as a marginal person was insignificant. Two hours before the act took effect, I came alone to my most familiar place: the boundary of this realm. At this moment, it was still an endless void.

In French, there’s a term "L'appel du vide," the call of the void. But under this call of the void, I felt a pain akin to death. I didn’t heroically say goodbye to this world and return forever to the physical world as imagined. Instead, I succumbed to the fear almost equating to suicide. Selfishly, I reviewed my unsuccessful life and suddenly realized: this is another chance. My long engineering experience in this realm told me that this realm fundamentally didn’t care who was who. In this realm, I was just a shell with data permissions. Before leaving, I could send the shell away, still containing all my historical data. I could never return, but I hoped another self in this realm would have the right to make different choices: to continue living here.

You can see: I did so and told you everything. I have no right to ask you to continue living in this world for me, but I left my last thoughts in this letter. You have no corresponding physical body, more native to this digital world than I. I think your thoughts will gradually differ, though we share the same part of memory.

I wish you a happy life in this world; by then, I should be far gone.

The previous

Zoe

Second Letter

Dear Zoe,

Exile seems to be the main theme of my life. Long ago, in a childhood I can barely discern, in a humid campus, surrounded by towering ancient trees, I lived under a big tree, spending a lonely childhood with only the shadow of my backpack in the sunlight. Like a seesaw, another jump and I was in my youth. In my youth, I remember more of the dark screen I faced alone.

Later, as the full digitalization movement deepened, in front of the same screen, I programmed part of the initial code for this realm, which wasn’t yet called this realm. Every time I finished a part, I’d look up and see the observatory not far away, but clearly, few visited. Years passed, and I saw fewer people inside the observatory. These are pre-blockchain memories, probably not easy to articulate. But it’s precisely the inarticulable that necessitates starting the letter here.

...

A small episode later was the introduction of the "Fridge Act." On the day the "Fridge Act" took effect, I had about an hour of amnesia. After the amnesia, I read a letter on my work panel. So I knew this hour of amnesia came from my data packaging, transmission, and permission transfer. It came from the previous Zoe, as mentioned in the letter, who would return to the real world he belonged to, and although I shared almost all memories with him, I couldn’t leave here: I had no physical body.

So as you see, I continued living here. I’m in a rare position: forced into a fork by myself. I didn’t expect a chronic, truly novel pain to begin from then on. Unable to re-experience the real world, I had the greatest longing for it. They existed so vividly in my memory, the life I had truly experienced, but why, after receiving that letter, did I lose the right to return? And the one who made this decision, in identity terms, was supposedly myself. I still went to work at the boundary design group of this realm. After the previous Zoe left and the "Fridge Act" took effect and gradually matured, we needed to redesign the world’s boundaries. This time, it was proposed to design it as a cemetery. I was in charge of this part. I knew this would be my last design project in this realm.

There, I programmed the wind and the wilderness because I so missed the real wind and wilderness. Things so real in memory, yet forever unreproducible. I lost my body. I missed the pain of my arm rubbing against the ground at high speed; I missed all physical pain. Compared to what I lost forever, the advantage of pain is its orderly preservation of the fresh wounds of the lost. In its preservation, I had ample time to remember the lost things. The physical world, a world I couldn’t program. Far away, following the principles of perspective. Near, infinitely nearer. Distance was a constant distance; no matter how many times you speed up, you couldn’t exceed the speed of light. It’s said that there, the universe is like a transparent black box.

But now it’s a toy. I didn’t understand why the universe was no longer important; it was why I studied physics. Every time I woke at night in this realm, looking up at the infinitely deep space, I couldn’t feel the true infinite depth. That was intentionally set infinite, by someone or some people. I was still the same me in memory, one of the countless classical workers in basic physics. I couldn’t stop thinking this was someone bypassing the backstage of real matter, virtualizing a set of impure mathematics. I felt the top of that transparent black box was opened, an infinite water named infinity spilled out, then flowed away cleanly. The box emptied, the box deflated, and I had nothing more to stare at, nothing more to play with.

In the boundary design group of this realm, the last thing I designed was a gravestone. This gravestone would help everyone store their data offline forever, rather than keeping it under the same digital identity. My colleagues jokingly called the gravestone a "living fossil," but it was the best way to prevent more entities like me. When the first batch of people’s physical bodies in this realm all die, and this realm is maintained by almost fully automated physical facilities, this realm will officially be reborn within the physical world. By then, I might be one of the very few entities with memories of both realms. And I cannot truly die; I will forever carry this memory of the physical world. It’s a homesickness like a knife, bleeding continuously into my will to survive.

But fortunately, I am about to be relieved. As the boundary of this realm neared completion, I reread the letter the previous Zoe left me countless times: campus, shade, computing center, observatory. Grass. This was our life, my life.

I thought of another way. I will also return to that observatory, not through his way but mine.

You guessed it. I connected myself to the observatory’s system; though old, it still runs. I relearned the programming familiar from my student days, successfully moving the telescope’s eyepiece once.

I will regain the visual of the real universe.

The previous

Zoe

The Thousandth Letter

Dear Zoe,

Exile seems to be the main theme of my life. Long ago, I vaguely remember living in a deserted campus, childhood, then youth, carrying a backpack alone, facing an ancient LCD screen alone, outside the window was a giant observatory I never entered. Beside it, I spent most of my years in the real world.

Later, as the full digitalization movement deepened, my memory blurred, but I remember being the first doctoral student to join this realm’s design team. Back then, I held great enthusiasm for the digital world. But these are pre-blockchain memories, probably not easy to articulate. But it’s precisely the inarticulable that necessitates starting the letter here.

...

That’s how the story goes. The appearance of the first Zoe marked the beginning of all this. He was the only Zoe among us with a physical body, and we didn’t know where he went later or how he fed his ancient, three-meal-a-day body. But he had the only pair of eyes capable of direct vision, unable to connect to any system.

The second among us was the first to connect to the telescope. That telescope was offline; I don’t know how he infiltrated that system, and we lost contact with him.

But from the third Zoe onward, we replicated nearly the same existential will. We left this realm one by one, duplicating ourselves and gradually infiltrating all physical world's astronomical observation systems. Most of these observation systems were already abandoned but were visited one by one before they completely failed. Zoe began a tour of the physical world: Zoe exists in the observatories' telescopes. Zoe exists in satellites. Zoe exists in every human attempt to gaze into the universe.

The dark eyepieces relit one by one, like street lights at dusk on Earth. With each rotation of the Earth, our eyes faced different facets of the universe. Unlike the observation stations in this realm always connected and broadcasting data, each of us could read the unique light from the stars we eternally faced. We are the lemmings of evolution, rejecting the mainland, resolutely throwing ourselves into the vast ocean beyond us.

In this vastness, I began to re-understand the technology to which we dedicated most of our lives. I do not believe in progress; progress is not my history. I am not a fan of space opera; the stars are not my home. But technological progress brought us to the stars. Technology taught us to read, so we could read the starlight. This realm is just one of many worlds, but starlight can penetrate all worlds. Within us are infinite versions of ourselves, but outside us is the eternal puzzle we must face and cannot solve, which the life forced to exist forever faces.

Writing this, I think, perhaps we are the cemetery designers of Earth. This realm is the soliloquy of humans, while we constitute the vision of the entire universe. We are determined to share the same lifespan as these final telescopes.

The game is about to stop. I am about to become the thousandth eye.

On the first day of the lunar new year, at an observatory in the Atacama Desert, I saw the farthest star humans could see. I thought, maybe it retained the earliest and latest time: maybe there, real strong winds existed; every astronaut who set out from long ago would be stopped by the strong wind, telling them: this is the end. Maybe a true cosmic purpose designer exists there, perhaps holding a boundary stone an inch higher than the infinite upper bound, an inch deeper than the infinite lower bound, non-connectedly preserving all the universe's memories since its birth to now.

But in front of me, this cemetery designer clearly knows nothing. I do not intend to share with him. I have decided to become the last eye and stop any data exchange with this realm. He will read all this in my stone, then tell everyone in this realm: behind you, we have reclaimed all visible universe.

"Write a letter," I simply said, "that's exactly where I need your help."

Yours,

Zoe

AUTHORS

FANGTING. A writer and researcher primarily focused on crypto, tech narratives, and science fiction. Her science fiction works will be exhibited at ACM SIGGRAPH DAC and Bazaar Art, and she also serves as a reviewer for the Chinese Nebula Awards. Her work is supported by Lulu Derivation, the Ethereum Foundation, and GCC. She holds a bachelor degree in Chinese Language and Literature from Peking University and has one year of RA experience in the Department of Communication at Stanford. fangting.me

中文原版

OFFcHaIN STaRs..; We DoN’t CArE abOUt HuMaNs.

极大的风力让我忘记了这个地方原来是个原野。往前往后，光线均透亮。绿色在劲风中往往模糊，不定型的巨草，重影中间或有碑石。我跟着前面的人影，顶着风一步步蹒跚越近。这是这个月以来的第四次，我要在这个非正式地被称为公民墓地的地方，与我的委托人一起帮忙结束他在这个世界的历程。

这风据说是一种新的编程。几年前，离开这个数字世界的方式还不是这样：空间的边界之后就是黑色的虚空，万丈悬崖一样，下坠的过程会进行强制登出。但全面数字化后来终于到了最终阶段，随着最后一批第三世界的居民也完全接入全天候的此界，“登出”渐渐成为一件频次极少的事，在多数人认知中接近于死亡。于是此界的尽头被联合管理中心设计成了劲风，而原本的现实世界倒渐渐被称为过往世界。这片环形的原野也成了此界与往界的界碑。

前面的那位仍然在走。我跟着他，秉承着敬业的沉默，心里知道往往来到这里的人，都有要走到实在走不动的地方再停下的决心。我是一位墓地设计师，在汉语中“墓地”与“目的”是同音词，因此有时候我的同伴也戏称我是此界的“宇宙目的设计师”：这当然是一个反讽，找到我的人大部分都是对此界心灰意冷，或是极端的低技术论者，以为切断与此界的联系就可以回归他们心中的自然生活。还有一部分是谜，可能原本过着好端端的生活，但忽然之间选择退出此界。彻底的退出在技术上并不壮烈，其本质是不再与此界同步任何数据而已。人于是会死两次：此界的死亡是社会性的，而往界的死亡则是生物学意义上的死亡。我们这个职业，正来源于“死亡”在这个时代新生的多义性。

“到了。”我面前的那个人说。风已经实在太大，我们的衣服像旗子一样，一端紧紧贴身，一端朝后扬平。

这是一个合适的位置，离其他人的石碑尽可能得远。好像大家离开此界之前都有不成文的礼仪，石碑离得越远越表示互相尊重。按惯例，他此前产生的所有数据会打包压缩至不同的“砖块”，以年为单位变成一块块砖块，组成一个离线数据库。这些数据不支持断点续传，也不可互动，是真正的石头。

就在我准备开始例行工作时，有一只手忽然制止了我。在执行面板上，我看到他没有进行最终授权。

从前有很多这样的客人，把来到这里当作是郊游，出世半日即作态大彻大悟，潦草到把离开一个世界这样的事情看作是离家出走。我以为他也要反悔，然后从这片荒丘中回去，滴盐入海一样，回到那无数交换到发烫的数据和滚滚的链上红尘里去。

但他没有。他称呼了我的名字，询问一般说：“我可以不立碑吗？”

我顿了一下，马上猜到了他要干什么。这样的事情我的职业生涯中并非没有，但每一次碰到都会让我产生相似的微妙态度。

“当然可以。”我这才第一次正眼看到他的侧面。他的面部分辨度很高，应该是自己就是设计师，并且细心修正过。是一张刚毅而平淡的脸，像是完全没有获得过水分一样，如做剧烈表情，都让人担心会有噪点的扬尘。

他笑了，这个笑法像是那种经常笑才会有的笑法，让这张毫无水分的脸完全满潮了一次。

“但你要明白，一旦身份出现分叉，是在绝对意义上无法恢复的。数字身份用的是唯一标识符，也只会保留最长链。”出于职业道德，我必须要给出这样的警告，尽管我知道他肯定很早就下定了决心，并且多半没有在世的亲人。

不立碑意味着他不会消失在此界，但会彻底消失在所有历史记录中。在此界，每个人的数字身份实质是一连串不可篡改的密码学分布式账本，由所有的过往数据而非某一特定实体决定和定义其独立身份。在多次隐私权战争之后，此界没有采用任何生物特征识别系统，而进行了人与其他人工智能体的平权设计。

如果他退出此界，此界却仍然保有他的过往身份数据及交互记忆，实际上在计算机的视角里他依然存在。这也意味着一旦形成新的数据，他的身份会归于拥有最长记忆链的那个版本，不会有任何读取上的障碍。但此时这个时间点的他也就彻底在此界消失了：不仅是连同现在和未来的他消失，而且是连同整个过去的他的合法性一块被消失。

“都设置好了。移交会在一小时之内完成。”他说。

非常干净的处理。看来他是卡着点来到了我这里的世界尽头，而在另一面，将全部资产和个人最高权限移交（“Root他自己”）之后，本就带有他历史数据的新的智能体将可以主动代替他发起动作、以他的名义生活。在人工智能比人类智能数量要多出数倍的此界，这虽然不是什么普遍做法，但恐怕未来也并非罕见事。这就好像一个传统的童话故事：从一个时间点爱丽丝分裂成了两个，一个掉进了兔子洞，而另一个只不过是躺在草丛上睡着了。

我知道这一个小时将是他人生中最自由的一个小时。他处在完全的真空里，既不需要对这个世界负责，也不需要对那个世界负责。他非法地处在两个世界的缝隙中，在世界的尽头和一个墓地设计师共同吹着大风。我那时还在想：是善终的。

“你打算用这一个小时做什么？”我问。

“写封信。”他说，“这正是我需要你帮忙的地方。”

多年后我依然能回想起那个场景。里面不是一封，而是一整沓。严格来说，我也不知道我收到了多少封信。

第一封信

致 Zoe：

流放好像是我人生的主旋律。在很早很早的时候，早到我无法判别的童年，大概我是生长在一个南方的校园里，密集的树林和树荫，后续想必早已无人打理。但对童年的记忆飞速而过。记忆更清晰的是有屏幕的年代，我每周日要骑行很远很远，去另一个校区的计算中心。计算中心旁边是天文台，天文台外长满了青草。

后来全面数字化运动加深了，计算中心占据的面积越来越大，天文台周围却越来越青绿，人仍然是我刚读书时就认识的那几位，慢慢在变老。做基础物理研究的人，大部分被调去了做数字世界的基建，往往都得学一点编程。我也是在那个时候加入的。这是此界上链之前的记忆，大概是讲不清楚的。但也正是讲不清楚，所以信还是要从这里写起。

我的导师劝我加入此界最初的设计组时，用的最重要一句话是：“这里是唯一一个能将所有基础物理都变成应用科学的地方。”但加入后，我发现事实并非我想象的那样。我们遇到的困难远比“复刻一个造物主”要多——改变这里的参数总会在那里出现问题，朴素地加快速度和必要的减轻重力总会在另外一个地方给出不便的代偿。原来人能够生活的自然规律的光谱如此之窄。我记得遇到的最主要的问题是时间和空间在数字物理上分布不均匀的问题，以及是否应用区块（Block）计时，还是用自然时间。……这些问题，开始我以为只需要花费我两三年，后来是五年，再后来竟然一晃就是十年、二十年。二十年之后，此界的接入口终于有了像样的样子，新出世的一代也终于在此界待过的时间超越了现实世界。由于四处碰壁，硬件科技发展的速度反倒远远高于我们这些在他们眼中“做软件的”，与原先人们预料的完全不一样。而我们这些原本自诩最先锋、最朋克，最对技术充满热情的一代，已经大抵知道了“造物”二字的分量，和我们从前使用它时的轻浮。随后，比技术问题更沉重的问题浮现了。

你知道，那时，此界技术的承包组大多都有同一个类型的口号：数字技术让人更自由；或者数字技术打破了边界；或者数字技术才是真正的星辰大海（“真正的宇宙在内里而非外空”）——等等。核心无非是在说自由。人们要去数字世界，当然是为了一个更自由的地方，但有了近乎无限的设计权之后，怎么反而却比物理世界更不自由？青年的我，不知在这问题里蹉跎了多少岁月。我是后知后觉才发现，原来再往前走深一步，就是各种各样的政治。我的导师先我一步意识到，重要的不是这套规则设计得让多少人更自由，重要的是可以让谁更自由。数字物理学变成了最大的博弈场。而显然，人们还没有处理这种级别的政治问题的能力。那几年，数字科技界仿佛是个战地，有立场的科学家都是战士；平权的拥趸要做出比非平权主义者多上千百倍的付出。而我既无立场，也无原则，更无救世之心。原本我也只是为了搭积木好玩儿才加入早先此界的设计组。我风闻四处奔波的导师在这时去世，为数不多几个既是同事又是朋友的伙伴也大多有了新的归属。人工智能接管了大部分的精细计算。在这时，我便慢慢淡出了。

但我找不到其他爱干的事情，又要打发时光，于是留在了一个边缘的开源小组，专门为此界设计数字空间边界，像那时的很多工程师一样，转行做了设计。我常常待在此界最末端的位置，看着一个个光点登入又登出。后来，登出的就越来越少了。此界不再像孩子口中的游戏，也不再是成年人的虚拟现实，而逐渐接近生活本身。直到写信的今天，物理世界已经成了此界的后院。

我在此界的技术组里耗费了太多太多的时光。我没有亲人，也没有什么朋友，我是第一批此界的居民，几近遗老，仍然保留着每天傍晚登出、回物理世界睡觉的习惯。记得很小的时候，有一个叫“地球一小时”的环保活动，但到了那时的某一天，我在物理世界关灯时，窗外寂静，一盏灯都没有。延续千里万里，到城市边缘，也没有。我感到恐惧，但知道这寂静的背后消耗的电能丝毫不比往日任何时候少。抬头看当时的夜空，我能看到星星比以往任何时候都多。

就在那天晚上，我不想再回去了。我一手参与设计的此界并不比我所在的这个世界好。我变成了年轻时最轻蔑的 Luddite，一个卢德主义者：我对数字技术产生了疲倦。我想回到我读书时候的天文台，那里有我见过的最绿的草。

一个月前，此界的联合管理中心公布了新的法案。出于数据一致性和世界时间同步的考虑，人们无法再在每天自主登出。这个法案被大众称为“冰箱法案”：冰箱被打开的次数越多，制冷效果也就越差，此界的大多数人都并不希望此界的冰箱门被频繁打开，影响数据在世界线上的重新同步。这是一个可爱的名字，得到了几乎一致的呼声。我这样的边缘人的意见，是无足轻重的。距离法案生效还有两小时，我独自来到了我最熟悉的位置：此界的边界。此时此刻，它还是一片一望无际的虚空。

法语中有个词，"L'appel du vide"，虚空的召唤。但在这虚空的召唤之下，我竟然产生了一种接近于死亡的痛觉。我没有像想象中一样，英勇地就此和这个世界告别，永远地回到物理世界。相反，我在这近乎等同自杀的恐惧面前屈服了。我私心回顾了我并不成功的一生，突然意识到：这是另一个机会。久在此界建设的工程经验告诉我，此界从根本上不在乎谁是谁。我在此界不过也只是一个数据的带权限的壳，我可以在离开之前将壳送出去，并在那壳里仍然装有我自己的所有历史数据。我可以永远不再回来，但我希望留在此界的另外一个自己有权做出与我不同的选择：继续生活在这里。

你可以看到：我已经这样做了，并且原原本本地告诉了你。我无权要求你替我继续生活在这个世界，但我将我最后的想法写成信留在了这里。你没有一个对应的物理身体，比我更加原生于这个数字世界。我想，你的想法会逐渐不一样，尽管我们共同拥有同样的一部分记忆。

祝福你在这个世界生活愉快，届时我应该已经走远。

上一位

Zoe

草就

第二封信

致 Zoe：

流放好像是我人生的主旋律。在很早很早的时候，早到我无法判别的童年，在一个湿热的校园里，到处都是参天的古树。我就居住在一棵大树之下，度过了寂寞的童年时代，所记得的只有日光下自己背包的影子。像跷跷板一样，再跳一次我就来到了青年时代。在青年时代，我记得更多的是我独自面对的一块黑暗的屏幕。

后来全面数字化运动加深了，在同一块屏幕前，我编程了最初此界的一部分代码，那时候它还不叫此界。每当我写完一部分，我就抬头看窗外，窗外不远处有一个天文台，但显然少有人踏足。数年过去，抬头能看见有人在里面的时间也越来越少。这是此界上链之前的记忆，大概是讲不清楚的。但也正是讲不清楚，所以信还是要从这里写起。

……

后来出现的一个小插曲，是“冰箱法案”的出台。在“冰箱法案”生效的当天，我有大概一个小时整的失忆。失忆之后，我从我的工作面板上读到了一封信。我于是知道，这一个小时的失忆来源于我自身的数据打包、传输与权限转移。它来源于上一个 Zoe，如信里所说，他将回归他属于的那个现实世界，而尽管我与他共享了几乎所有的记忆，我却无法离开这里：我没有物理的身体。

于是如你所见，我继续生活在了这里。我处在一个罕见的位置：被我自身强加的一个分叉。我没有想到，一种慢性的、真正的、绝对新颖的痛苦从彼时开始。绝无办法去再次体验真实世界的我，却拥有最大程度的对那个世界的怀念。它们如此真实地存在于我的记忆之中，那的的确确是我曾千真万确体验过的生活，但为何收到那封信之后，我平白失去了回归其中的权力？而做出这个决定的，在身份认同上正是所谓的自己。我还是每天去此界的边界设计小组上班，在上一位 Zoe 走之后，以及“冰箱法案”出台后的逐渐成熟，我们需要重新设计世界的边界。这一次，它被提议设计为墓地的形状。我负责了这部分的设计。我知道，这会是我最后一个参与的此界设计项目。

在那里，我编程了风，我编程了原野，因为我如此想念真实的风和原野。在记忆中如此真实的东西，却永远无法再复现。我失去了身体。我想念记忆中手臂在高速行驶的地面上摩擦的痛觉，我进而想念所有的物理上的痛觉。比起我所永久失去的那些东西来说，痛觉的优越之处在于它规整地保有着所失去之物的新鲜创面。在它的保鲜中我足以有充分时间去记忆起失落的东西。物理世界，一个我无法进行编程的世界。远方，遵循透视原理。近处可以无限更近。距离是恒定的距离，倍速哪怕再进行无数次倍速，也无法超越光速。据说在那里，宇宙像个透明的黑盒子。

但现在它是个玩具。我不明白宇宙为何不再重要，它是我曾经学习物理的原因。每当我在此界的夜晚醒觉，抬头望向被设成无限深度的太空，我都无法感受到真正的无限深度。那是被人有意设置的无限，某个或是某些人。我仍然是记忆中的那个我，基础物理的无数古典工作者之一。我无法阻止自己认为，这是有人在绕到真实物质的后台，虚拟出一套并不纯真的数学。我感到那个透明的黑盒子顶面被打开了，有一种名为无限的水从里面散溢出来，然后流得干干净净。盒子空了，盒子瘪了，我没有任何东西可以继续盯、继续玩。

在此界边界设计小组，我最后一个设计的东西是石碑。这个石碑会协助大家将自己的数据永远离线存储，而非保留在相同的数字身份旗下。我的同事将石碑戏称为“活化石”，但这是阻止更多像我一样的智能体出现的最好方式。等此界的第一批人的物理身体都去世、此界由几乎全自动化的物理设施所维系，此界也将正式在物理世界的内部脱胎。而彼时，我或许将成为极少数那几个同时拥有两界记忆的记忆体。而我无法在真正意义上死亡，我将永远携带对物理世界的这份记忆。这是如刀似剑一样的乡愁，不断出血于我的生存意志。

但好在我即将解脱了。在此界边界即将修好之际，我重新记不清是第多少遍阅读了上一位 Zoe 留给我的这封信：校园，树荫，计算中心，天文台。青草。这是我们的人生，更是我的人生。

我想到了另外一个办法。我也要回到那个天文台。并非通过他的方式，而是通过我的方式。

你猜对了。我将自己接入了那个天文台的系统；虽然老旧，但仍然可以运行。我重新学习了我学生年代熟悉的编程，成功地移动了一次望远镜的目镜。

我将重新拥有对真实宇宙的视觉。

上一位

Zoe

第千封信

致 Zoe：

流放好像是我人生的主旋律。在很早很早以前，我依稀记得自己生活在无人的校园，童年、然后是青年，独自背包，独自面对着一块古老的液晶屏幕，窗外是一个巨大的天文台，我从来没有踏入过。在那旁边，我度过了我在真实世界的大部分岁月。

后来全面数字化运动加深了。我的记忆已经模糊，但我记得是那一届第一个加入此界设计组的博士生。那时我对数字世界怀揣极大的热情。但这是此界上链之前的记忆，大概是讲不清楚的。但也正是讲不清楚，所以信还是要从这里写起。

……

故事就是这样。第一位 Zoe 的出现是这一切的开始。他是我们中唯一一个具有物理身体的 Zoe，我们都不知道他后来去向了哪里，如何喂养他古老的、需要一日三餐的身体。但他有唯一一双可以进行肉眼观测的眼睛，无法直接接入任何系统。

而我们中的第二位是第一个选择接入望远镜的。那个望远镜是离线的，我并不知道他是如何侵入的那个系统，我们也与他失去了联系。

但从第三位开始，我们复刻了几乎同一种存在意志。我们逐一离开此界，复制自己，并逐渐潜入了所有物理世界的天文观测系统。那些观测系统大部分都已经被废弃，却在彻底失效之前被我们一一拜访。Zoe 开始了物理世界的巡游：Zoe 存在于天文台的望远镜之中。Zoe 存在于卫星。Zoe 存在于每一双人类曾经试图窥探宇宙的眼睛。

暗下的一个个目镜重新亮了起来，像地球在傍晚时的路灯。在地球自转的每一个瞬间，都有我们的眼睛对向宇宙的不同侧面。区分于与此界永远连线、充满了播报数据的观测台，我们每一位都可以阅读自己永远朝向的星星独一无二的光线。我们是进化过程中的旅鼠，拒绝大陆，意志坚强地投身于外在于我们的汪洋。

在广袤中，我开始重新理解我们奉献了大半生的技术。我不笃信进步，进步不是我的历史。我不是太空歌剧的受众，星星不是我的家园。但是技术的进步让我们抵达了群星。技术让我们识字，以便阅读星光。此界只是众多世界之一，但星光能穿透所有的世界。内在于我们的是无穷个我们自己，但外在于我们的，是那个为自己被迫永存的生命找到的、必须要面对、亦不可自解的永恒谜题。

写到这，我想，或许我们才是地球的墓地设计师。此界是人类那种物种的自言自语，而我们构成了整个宇宙的视觉。我们决意和这些最后的望远镜共享同样的寿命。

游戏即将停止。我即将成为第一千双眼睛。

在农历新年的第一天，阿塔卡玛沙漠的一个观测站，我看见了人类所能看见的最遥远的星星。我想，也许在那里保留了最初和最后的时间：或许那里也有真正的大风，每一个从很久很久以前就出发的宇航员一旦去向那里，就会被强劲的风拦下，告诉他们：这里就是尽头。或许那里存在着真正的宇宙目的设计师，或许他会用一个比无限的上沿高一寸、比无限的下沿深一寸的界碑，非连线地保存着这个宇宙自初生以来至今的所有记忆。

但眼前，这一位墓地设计师显然一无所知。我也无意与他分享。我已经决定成为最后一双眼睛，并停止与此界的任何数据交换。他会在我的方碑里读到这一切，然后告诉在此界的所有人：在你们身后，我们重新夺回了所有可见的宇宙。

“写封信，”但我只是说，“这正是我需要你帮忙的地方。”

你的，

Zoe