Death's End

by Cixin Liu

This beautiful world seemed unreal to Cheng Xin. Though awakened from hibernation, she felt as though she were in a dream.

  Half an hour later, the car landed and the door slid open automatically. Cheng Xin got out, and the car rose into the air and left. After the turbulence from the propellers subsided, silence reigned over everything, pierced by occasional birdsong from far away. Cheng Xin looked around and found herself in the midst of a group of abandoned buildings. They looked like residential buildings from the Common Era. The bottom half of every building was covered in ivy.

  The sight of the past covered by the green life of a new era gave Cheng Xin the sense of reality that she had been missing.

  She called for AA, but a man’s voice responded. “Hello.”

  She turned and saw a man standing on an ivy-covered second-story balcony. He wasn’t like the soft, beautiful men of this time, but like the men of the past. Cheng Xin seemed to be dreaming again, a continuation of her nightmare from the Common Era.

  It was Thomas Wade. He wore a black leather jacket, but he looked a bit older. Perhaps he had gone into hibernation after Cheng Xin, or perhaps he had awakened before her, or both.

  Cheng Xin’s eyes were focused on Wade’s right hand. The hand, covered by a black leather glove, held an old Common-Era gun that was pointing at Cheng Xin.

  “The bullet in here was designed to be shot underwater,” said Wade. “It’s supposed to last a long time. But it’s been more than two hundred and seventy years. Who knows if it will work?” That familiar smile, the one he wore when he was taking delight in the despair of others, appeared on his face.

  A flash. An explosion. Cheng Xin felt a hard punch against her left shoulder and the force slammed her against the broken wall behind her. The thick ivy muffled much of the noise from the gunshot. Distant birds continued to chitter.

  “I can’t use a modern gun,” said Wade. “Every shot is automatically recorded in the public security databases now.” His tone was as serene as it had been when he used to discuss routine tasks with her.

  “Why?” Cheng Xin didn’t feel pain. Her left shoulder felt numb, as if it didn’t belong to her.

  “I want to be the Swordholder. You are my competitor, and you’re going to win. I don’t harbor any ill will toward you. Whether you believe me or not, I feel terrible at this moment.”

  “Did you kill Vadimov?” she asked. Blood seeped from the corner of her mouth.

  “Yes. The Staircase Program needed him. And now, my new plan does not need you. Both of you are very good, but you’re in the way. I have to advance, advance without regard for consequences.”

  Another shot. The bullet went through the left side of Cheng Xin’s abdomen. She still didn’t feel pain, but the spreading numbness made her unable to keep standing. She slid down against the wall, leaving a bright trail of blood on the ivy behind her.

  Wade pulled the trigger again. Finally, the passage of nearly three centuries caught up with the gun, and it made no sound. Wade racked the slide to clear the dud out of the chamber. Once again, he pointed the gun at Cheng Xin.

  His right arm exploded. A puff of white smoke rose into the air, and Wade’s right forearm was gone. Burnt bits of bone and flesh splattered into the green leaves around him, but the gun, undamaged, fell to the foot of the building. Wade didn’t move. He took a look at the stump of his right arm and then looked up. A police car was diving toward him.

  As the police car approached the ground, several armed police officers jumped out and landed in the thick grass waving in the turbulence thrown up by the propellers. They looked like slender, nimble women.

  The last one to jump out of the car was AA. Cheng Xin’s vision was blurring, but she could see AA’s tearful face and hear her sobbing explanation.

  “… faked my call…”

  A fierce wave of pain seized her, and she lost consciousness.

  When Cheng Xin woke up, she found herself in a flying car. A film clung to her and wrapped her tightly. She couldn’t feel pain, couldn’t even feel the presence of her body. Her consciousness began to fade again. In a faint voice that no one but herself could hear, she asked, “What is a Swordholder?”

  Excerpt from A Past Outside of Time

  The Ghost of the Wallfacers: The Swordholder

  Without a doubt, Luo Ji’s creation of dark forest deterrence against Trisolaris was a great achievement, but the Wallfacer Project that led to it was judged a ridiculous, childish act. Humanity, like a child entering society for the first time, had lashed out at the sinister universe with terror and confusion. Once Luo Ji had transferred control of the deterrence system to the UN and the Solar System Fleet, everyone thought the Wallfacer Project, a legendary bit of history, was over.

  People turned their attention to deterrence itself, and a new field of study was born: deterrence game theory.

  The main elements of deterrence are these: the deterrer and the deteree (in dark forest deterrence, humanity and Trisolaris); the threat (broadcasting the location of Trisolaris so as to ensure the destruction of both worlds); the controller (the person or organization holding the broadcast switch); and the goal (forcing Trisolaris to abandon its invasion plan and to share technology with humanity).

  When the deterrent is the complete destruction of both the deterrer and the deteree, the system is said to be in a state of ultimate deterrence.

  Compared to other types of deterrence, ultimate deterrence is distinguished by the fact that, should deterrence fail, carrying out the threat would be of no benefit to the deterrer.

  Thus, the key to the success of ultimate deterrence is the belief by the deteree that the threat will almost certainly be carried out if the deteree thwarts the deterrer’s goals. This probability, or degree of deterrence, is an important parameter in deterrence game theory. The degree of deterrence must exceed 80 percent for the deterrer to succeed.

  But people soon discovered a discouraging fact: If the authority to carry out the threat in dark forest deterrence is held by humanity as a whole, then the degree of deterrence is close to zero.

  Asking humanity to take an action that would destroy two worlds is difficult: The decision would violate deeply held moral principles and values. The particular conditions of dark forest deterrence made the task even harder. Should deterrence fail, humanity would survive for at least one more generation. In a sense, everyone alive would be unaffected. But in the event of deterrence failing, carrying out the threat and broadcasting would mean that destruction could come at any moment, a far worse result than not carrying out the threat. Thus, if deterrence failed, the reaction of humankind as a whole could be easily predicted.

  But an individual’s reaction could not be predicted.

  The success of dark forest deterrence was founded on the unpredictability of Luo Ji as an individual. If deterrence failed, his actions would be guided by his own personality and psychology. Even if he acted rationally, his own interests might not match humanity’s interests perfectly. At the beginning of the Deterrence Era, both worlds carefully analyzed Luo Ji’s personality and built up detailed mathematical models. Human and Trisolaran deterrence game theorists reached remarkably similar conclusions: Depending on his mental state at the moment deterrence failed, Luo Ji’s degree of deterrence hovered between 91.9 percent and 98.4 percent. Trisolaris would not gamble with such odds.

  Of course, such careful analysis wasn’t possible immediately after the creation of dark forest deterrence. But humanity quickly reached this conclusion intuitively, and the UN and the Solar System Fleet handed the authority to activate the deterrence system back to Luo Ji like a hot potato. The entire process from Luo Ji turning over the authority to getting it back took a total of eighteen hours. Yet that would have been long enough for droplets to destroy the ring of nuclear bombs surrounding the Sun and deprive humanity of the ability to broadcast their locations. The Trisolarans’ failure to do so was widely considered their greatest strategic blunder during the war, and humanity, covered in cold sw
eat, let out a held breath.

  Since then, the power to activate the dark forest deterrence system had always been vested in Luo Ji. His hand first held the detonation switch for the circumsolar ring of nuclear bombs, and then the switch for the gravitational wave broadcast.

  Dark forest deterrence hung over two worlds like the Sword of Damocles, and Luo Ji was the single hair from a horse’s tail that held up the sword. Thus, he came to be called the Swordholder.

  The Wallfacer Project did not fade into history after all. Humanity could not escape the Wallfacers’ ghost.

  Although the Wallfacer Project was an unprecedented anomaly in the history of humankind, both dark forest deterrence and the Swordholder had precursors. The mutual assured destruction practiced by NATO and the Warsaw Pact during the Cold War was an example of ultimate deterrence. In 1974, The Soviet Union initiated the Perimeter System (Russian Система «Периметр»), or “Dead Hand.” This was intended to guarantee that the Soviet Union possessed a viable second-strike capability in the event that an American-led first strike eliminated the Soviet government and high-level military command centers. The system relied on a monitoring system that gathered evidence of nuclear explosions within the Soviet Union; all the data was transmitted to a central computer that interpreted the data and decided whether to launch the Soviet Union’s nuclear arsenal.

  The heart of the system was a secret control chamber hidden deep underground. If the system determined that a counterstrike must be launched, an operator on duty would initiate it.

  In 2009, an officer who had been on duty in the room decades earlier told a reporter that at the time, he was a twenty-five-year-old junior lieutenant, freshly graduated from Frunze Military Academy. If the system determined that a strike was necessary, he was the last check before the complete destruction of the world. At that moment, all of the Soviet Union and Eastern Europe would likely be a sea of flames, and all of his loved ones above ground almost certainly dead. If he pushed the button, North America would also turn into hell on Earth in half an hour, and the following nuclear winter would doom all of humanity. He would hold the fate of human civilization in his hand.

  Later, he was asked this question many times: If that moment had really arrived, would you have pushed the button?

  The first Swordholder in history answered: I don’t know.

  Humanity hoped that dark forest deterrence would have a happy ending, like the mutually assured destruction of the twentieth century.

  Time passed in this strange balance. Deterrence had been in effect for sixty years, and Luo Ji, who was now over a hundred, still held the switch to initiate the broadcast. His image among the populace had also gradually changed.

  Hawks who wished to take the hard line against Trisolaris did not like him. Near the beginning of the Deterrence Era, they advocated imposing more severe conditions on the Trisolarans, with the goal of completely disarming Trisolaris. Some of their proposals were absurd. For instance, one idea was the “naked resettlement” program, which would have demanded that all Trisolarans dehydrate and allow themselves to be transported by cargo ships to the Oort Cloud, where they would be picked up by human spaceships and brought to the Solar System to be stored in dehydratories on Mars or the moon. Thereafter, if the Trisolarans satisfied certain conditions, they would be rehydrated in small batches.

  The doves, similarly, did not like Luo Ji. Their primary concern was whether the star 187J3X1, whose location had been broadcast by Luo Ji, had possessed planets that harbored life and civilization. No astronomer from the two worlds could definitively answer this question: It was impossible to prove the affirmative or the negative. But it was certain that Luo Ji could be suspected of having committed mundicide. The doves believed that in order for humanity and Trisolaris to peacefully coexist, the foundation must be universal “human” rights—in other words, the recognition that all civilized beings in the universe had inviolable, fundamental rights. To make such an ideal into reality, Luo Ji must be tried.

  Luo Ji ignored them all. He held the switch to the gravitational wave broadcast system and silently stood at the Swordholder post for half a century.

  Humanity came to realize that all policies with respect to the Trisolarans had to take the Swordholder into account. Without his approval, no human policy had any effect on Trisolaris. Thus, the Swordholder became a powerful dictator, much like the Wallfacers had.

  As time passed, Luo Ji slowly came to be seen as an irrational monster and a mundicidal despot.

  People realized that the Deterrence Era was a strange time. On the one hand, human society had reached unprecedented heights of civilization: Human rights and democracy reigned supreme everywhere. On the other hand, the entire system existed within the shadow of a dictator. Experts believed that although science and technology usually contributed to the elimination of totalitarianism, when crises threatened the existence of civilization, science and technology could also give birth to new totalitarianism. In traditional totalitarian states, the dictator could only enact his control through other people, which led to low efficiency and uncertainty. Thus, there had never been a 100 percent effective totalitarian society in human history. But technology provided the possibility for such a super-totalitarianism, and both the Wallfacers and the Swordholder were concerning examples. The combination of supertechnology and a supercrisis could throw humankind back into the dark ages.

  But most people also agreed that deterrence remained necessary. After the sophons unblocked the progress of human technology and the Trisolarans began transferring their knowledge to humans, human science had advanced by leaps and bounds. However, compared to Trisolaris, Earth was still behind by at least two or three technology ages. Decommissioning the deterrence system was to be considered only when the two worlds were approximately equal in technology.

  There was one more choice: turning over control of the deterrence system to artificial intelligence. This was a choice that had been evaluated seriously, and much effort was expended in researching its feasibility. Its biggest advantage was a very high degree of deterrence. But ultimately, it wasn’t adopted. Handing over the fate of two worlds to machines was a terrifying idea. Experiments showed that AIs tended not to make correct decisions when faced with the complex conditions of deterrence—unsurprising, since correct judgment required more than logical reasoning. Moreover, changing from a dictatorship-by-man to a dictatorship-by-machine wouldn’t have made people feel any better, and was politically worse. Finally, sophons could interfere with AI reasoning. Though no example of such interference had been discovered, the mere possibility made the choice inconceivable.

  A compromise was to change the Swordholder. Even without the above considerations, Luo Ji was a centenarian. His thinking and psychological state were becoming more unreliable, and people were growing uneasy that the fate of both worlds rested in his hands.

  Deterrence Era, Year 61

  The Swordholder

  Cheng Xin’s recovery proceeded apace. The doctors told her that even if all ten seven-millimeter bullets in the gun had struck her, and even if her heart had been shattered, modern medicine was capable of reviving her and fixing her up good as new—though it would have been a different matter if her brain had been hit.

  The police told her that the last murder case in the world had occurred twenty-eight years ago, and this city hadn’t had a murder case in almost forty years. The police were out of practice when it came to the prevention and detection of murder, and that was why Wade had almost succeeded. Another candidate for the Swordholder position had warned the police. But Wade’s competitor had presented no proof, only a suspicion of Wade’s intent based on a sensitivity that this era lacked. The police, dubious of the accusation, wasted a lot of time. Only after discovering that Wade had faked a call from AA did they take action.

  Many people came to visit Cheng Xin at the hospital: officials from the government, the UN, and the Solar System Fleet; members of the public; and, of cou
rse, AA and her friends. By now, Cheng Xin could easily tell the sexes apart, and she was growing used to modern men’s completely feminized appearance, perceiving in them an elegance that the men of her era lacked. Still, they were not attractive to her.

  The world no longer seemed so strange, and Cheng Xin yearned to know it better, but she was stuck in her hospital room.

  One day, AA came and played a holographic movie for her. The movie, named A Fairy Tale of Yangtze, had won Best Picture at that year’s Oscars. It was based on a song composed in busuanzi verse form by the Song Dynasty poet Li Zhiyi:

  You live at one end of the Yangtze, and I the other.

  I think of you each day, beloved, though we cannot meet.

  We drink from the same river.…

  The film was set in some unspecified ancient golden age, and told the story of a pair of lovers, one who lived at the source of the Yangtze, and the other at its mouth. The pair was kept apart for the entire film; they never got to see each other, not even in an imaginary scene. But their love was portrayed with utter sorrow and pathos. The cinematography was also wonderful: The elegance and refinement of the lower Yangtze Delta and the vigor and strength of the Tibetan Plateau contrasted and complemented each other, forming an intoxicating mix for Cheng Xin. The film lacked the heavy-handedness of the commercial films of her own era. Instead, the story flowed as naturally as the Yangtze itself, and absorbed Cheng Xin effortlessly.

  I’m at one end of the River of Time, Cheng Xin thought, but the other end is now empty.…

  The movie stimulated Cheng Xin’s interest in the culture of her new era. Once she recovered enough to walk, AA brought her to art shows and concerts. Cheng Xin could clearly remember going to Factory 7984 and the Shanghai Biennale to see strange pieces of contemporary “art,” and it was hard for her to imagine how much art had evolved in the three centuries she was asleep. But the paintings she saw at the art show were all realistic—beautiful colors enlivened with vitality and feeling. She felt each painting was like a heart, beating gently between the beauty of nature and human nature. As for the music, she thought everything she heard sounded like classical symphonies, reminding her of the Yangtze in the movie: imposing and forceful, but also calm and soothing. She stared at the flowing river until it seemed that the water had ceased moving, and it was she that was moving toward the source, a long, long way.…