The Dark Forest

For other uses, see Dark Forest.

The Dark Forest

Cover page
Author	Liu Cixin
Original title	黑暗森林
Translator	Joel Martinsen
Language	Chinese
Series	Remembrance of Earth's Past
Genre	Science fiction, Hard science fiction
Publication date	2008
Publication place	China
Pages	400
ISBN	978-1784971595
Preceded by	The Three-Body Problem
Followed by	Death's End

The Dark Forest (Chinese: 黑暗森林, pinyin: Hēi'àn sēnlín) is a 2008 science fiction novel by the Chinese writer Liu Cixin. It is the sequel to the Hugo Award-winning novel The Three-Body Problem (Chinese: 三体, pinyin: sān tǐ) in the trilogy titled "Remembrance of Earth's Past" (Chinese: 地球往事, pinyin: Dìqiú wǎngshì), but Chinese readers generally refer to the series by the title of the first novel. The English version, translated by Joel Martinsen, was published in 2015.

Plot

Setting

Earth is under total surveillance by sophons, sub-atomic surveillance devices sent by Trisolarans, inhabitants of a planet of the stellar system Alpha Centauri. The sophons have also blocked all further research into particle physics, thus stopping any further human scientific development. Trisolaris orbits three stars and due to the nature of the three body problem will eventually fall into one of the stars, thus Trisolaris seeks to colonize Earth for themselves. An invasion fleet has been launched which will arrive at Earth in 400 years.

Prologue

While visiting the grave of a colleague, Sociologist Luo Ji runs into Ye Wenjie, the spiritual leader of the Earth Trisolaris Organization. Due to his Astronomy background she suggests to him a new field of Cosmic Sociology, based on two axioms she had been thinking of: Survival is the primary need of civilization & civilization continuously grows & expands yet the total matter in the universe remains constant.

Meanwhile Evans in his last communication discovers that despite their advanced technology, the Trisolarans are incapable of internal monologue. They communicate via transmission of their thoughts directly into the electromagnetic spectrum, visible even at a distance. Thinking is synonymous with speaking to them. This revelation frightens the Trisolarians who cut off all contact with Evans and abandon the ETO.

Part I: The Wallfacers

Since the human mind is the only place the Trisolarans cannot see, the United Nations selects four men to be "Wallfacers", the keepers of plans known only to themselves, who are granted full access to the resources of the UN. In response the Trisolarans revive the remnants of the ETO tasking them with determining the plans of the wallfacers. These ETO agents subsequently become the wallbreakers. Research and development of any means of escape from the solar system is banned due to supporting Defeatism as well as against the values of humanity due to most of the initial plans solely benefitting the highest socioeconomic strata of humanity.

Luo Ji initially survives being narrowly crushed by a car accident that instead kills an uninterested lover. He is brought to the UN meeting by security forces where he attempts to refuse his Wallfacer status. He is injured shortly afterwards by another assassin with a gun, and discovers that his refusal of his wallfacer status is taken to be part of his plan. Resigned to his fate, Luo Ji demands to live in an isolated mansion where he begins a hedonistic life and has the woman of his dreams brought to him whom he eventually marries.

Wallfacer Frederick Tyler embarks on a campaign to create an army of Kamakazi fighter pilots to staff a swarm of fighters carrying hydrogen bombs to attack the fleet. Finding no luck in the Japanese who are disdainful of their history being put to use nor in a guerilla force in Afghanistan who have no hatred for Trisolaris due to the guaranteed destruction of the United States in the war he orders the implementation of drone control in the fighter craft as well as research into planetary bodies with significant bodies of water.

Manuel Rey Diaz in the meantime orders research and development into supermassive hydrogen bombs. Due to the scale of the bombs mechanics merging with the physics of stars he recruits Astronomers to assist in the development of said bombs, and shortly after develops a severe case of heliophobia.

Bill Hines in the meantime initiates research into the human brain, with the hope that if a way to boost human intelligence is discovered, humanity might be able to brute force it's way past the scientific block placed by the Sophons. He thus orders research into traditional, quantum, biomechanical, and Von Neumann super computers in order to further his research before entering hibernation.

Meanwhile Zhang Beihai a political officer in the Chinese Navy is tasked with laying down the foundations of Humanity's space force. He is a steadfast Triumphalist, believing that humanity will defeat the Trisolarian fleet. After seeing off his dying father, he develops a long private plan for how humanity will defeat Trisolaris and puts it into action.

Part II: The Spell

Frederick Tyler's plan is revealed by his wallbreaker. His plan was to utilize the swarm fleet to destroy the human fleet, and then transport a significant amount of water to the Trisolaran fleet. With the Trisolaran fleet believing in the sincerity of the swarm turncoats, they would allow the swarm to approach close enough upon which he would take manual control of the swarm and crash their hydrogen bomb payloads directly into the Trisolaran fleet ships. His plan revealed as well learning that the Trisolarans have ignored it, he falls into despair, exacerbated by the rest of the world believing the plans revelation to be part of his secret plan. After a meeting with Luo Ji, he commits suicide to finally be free of his wallfacer status.

Manuel Rey Diaz's wallbreaker reveals himself and explains that his heliophobia is a ruse intended to distract from his true focus on the sun. His plan was to slow down the orbit of Mercury with his hydrogen bombs, pushing it into the sun and causing a chain reaction where the sun's surface continuously expands to swallow up more planets in the solar system including Earth, thus denying the planet to the Trisolarans. At a UN meeting to hold him to account he blackmails the wallfacer committee with a biometric watch linked to secreted nuclear bombs within the city. Demanding a revocation of his wallfacer status and free leave to his home country of Venezuela. Upon arrival in Venezuela it is revealed that the bombs were a bluff, yet despite his escape he is promptly stoned to death by his people for his plan to place them in harms way.

Eventually, the UN kidnaps Luo Ji's wife and child, putting them in hibernation until the Trisolaran fleet arrives as a means of goading him to get to work. It is finally revealed to him that he is the only Human Trisolaris wants dead, and their initial attempts to discretely kill him implies that whatever fear they have of him is a weapon that can be shared with other humans. He begins his work as a Wallfacer, asking questions about how to transmit the information about the position of a certain star in the Milky Way to a potential third observer civilization. This causes the Trisolarans to become truly afraid of Luo Ji, so they redouble their efforts to kill him.

Research into more advanced super computers has failed, with only a modest improvement in traditional architecture, but it is enough to allow Bill Hines to image the entire human brain and all it's neurons. Through his work he and his wife Keiko Yamasuki accidentally discover a method of implanting an unbreakable belief into a human when a test subject develops hydrophobia & requires months of therapy to believe water isn't poisonous. He thus changes his plan to implanting Triumphalism into humanity's armed forces, and enters hibernation along with his wife until the doomsday battle.

Zhang Behai visits a rock collector to purchase meteorites. Certain propulsion researchers are advocating for medium drives in the space force which require ships to carry 2/3rds of their weight in fuel. Believing that this will severely handicap the human fleet, he assassinates said researchers with bullets made from the meteorites during a space walk photoshoot on a space elevator. Zhang Behai points out the possibility that Defeatism and Triumphalism might wax and wane in the population over the coming centuries, and a situation might occur where the humanity's armed forces are depleted of any hope before the coming battle. His superiors to counter this potential scenario select several political officers including Zhang Behai to enter hibernation in order to reinforce the future space force with Triumphalist soldiers. The ETO having observed his actions are worried about him, however Trisolaris is unconcerned with Triumphalism and is much more worried about defeatist humans.

Luo Ji uses the solar amplification technique to send out three images that show the relative position of star 187J3X1 in the universe. He says that it is a "spell against the planets of star 187J3X1", which will take one hundred years to be verified. The effects of the spell will be catastrophic, he predicts.

The Trisolarans' sympathizers on Earth nearly kill Luo Ji with a flulike illness targeted to his genome, called the 'bed flu'. Unable to be cured, Luo Ji is put into hibernation to await a future time when a cure can be found. In the meantime astronomers detect the launching of probes from the Trisolaran fleet to reach Earth 50 years ahead of the main fleet, the haste to reach Earth coinciding with the exact moment that Luo Ji made his announcement to the UN to broadcast the spell against 187J3X1.

Part III: The Dark Forest

Almost 200 years later, Luo Ji is awakened to discover a drastically changed world. There has been a massive ecological collapse as a result of the total militarization of Earth, turning much of the surface into a desert and reducing the human population to 3 billion people. In response, nation states excavated large caverns underground where hyper-technological arcological cities have been established. Earth has 3 fleets of spaceships numbering in the thousands, and independent of Earth to prevent mixing of the priorities of Earth Government caring for it's civilians and the Fleet government combating Trisolaris. Each ship is a stellar class battleship capable of interstellar travel at 15% light speed and armed with laser weapons, railguns, and nuclear bombs. Citing the fleet's strength, humans collectively assume that they can win against the Trisolarans; even with many discussing the potential for future peace talks with the Trisolarans. Luo Ji & Bill Hines are taken to a meeting of Solar Fleet Joint Conference (a descendent of the United Nations, facilitating governance between fleet command and earth governments). Citing Frederick Taylor's suicide and the logistical impossibility of Manuel Reyes plan (not enough fissile material to achieve the results he envisioned), the wallfacer project is chalked up to early crisis hysteria and disbanded. There Hines’s plan is revealed by his own wife, secretly an ETO agent and his wallbreaker. Hines was a Defeatist and an Escapist, and his mental seal instead of implanting Triumphalist beliefs into human armed forces instead implanted Defeatism. Several seals were made in secret by himself and given to implanted soldiers, to spread and induct other soldiers into defeatism. Hines had hoped that defeatism operating in secret might develop a way for humanity to escape the solar system and preserve the seed of humanity. This results in a shakeup of fleet command due to the potential of the seal making perfect defeatism sleeper agents. Luo Ji in the meantime survives multiple assassination attempts from an ETO created computer virus and has to flee to a surface town with Da Shi where there is less technology.

With a Trisolaran probe fast approaching, Zhang Beihai is given the position of acting captain of the flagship Natural Selection due to uncertainty of who in the fleet is imprinted by the mental seal. He deserts the Solar System to escape the Trisolarans' incoming fleet, revealing himself to be a secret Defeatist and his mission the entire time being to preserve a seed of humanity. 4 other stellar class warships begin pursuit of Natural Selection.

The Earth Fleet meets the Trisolaran probe in a massive formation of nearly all of Earth's starships. The probe, which appears to be a solid "droplet" of a mirror-like substance based on the strong interaction, arrives and activates during examination to attack the human fleet. The strong interaction force makes the droplet the strongest object in the solar system, and it's propulsion system allows it to perform impossible maneuvers such as instant 120° course changes at high speed. These two properties allow it to quickly smash through 100 ships a minute as a result of the human fleet grid formation. Ship weapons are useless against it, and ships that attempt to accelerate beyond human safety limits are still caught and destroyed. Only two ships survive the battle due to their crew being prepared for maximum acceleration in case the probe attempted to flee the fleet. The droplet then parks itself in a Lagrange point between the Earth and the Sun, where it broadcasts a powerful scrambling signal to prevent Earth from using the Sun's amplification mechanism again.

The surviving ships decide to escape the Solar System and head for nearby stars in hopes of founding civilization once again. However, the humans aboard these ships quickly realize there are only enough supplies for a single ship. The distances between ships hinder communication to allow for a calm discussion between ships. Thus, in both groups of ships, one crew initiates a first strike against the others before collecting supplies and resources and continuing their journey.

Back on Earth, Luo Ji and another contemporary, Da Shi, discover that star 187J3X1 has been destroyed, causing the UN to restore Luo Ji's Wallfacer status. Luo Ji explains to Da Shi the implications he derived from Ye Wenjie's two axioms of cosmic civilization: 1. Each civilization's goal is survival, and 2. Resources are finite. Like hunters in a "dark forest", a civilization can never be certain of an alien civilization's true intentions. The extreme distance between stars creates an insurmountable "chain of suspicion" where any two civilizations cannot communicate well enough to relieve mistrust, making conflict inevitable. Leaving a primitive civilization alone is not an option due to the exponential progress of technological change, and a civilization you have detected might easily surpass your own technological level in a few centuries and become a threat. If you have detected a civilization, then you have also confirmed that said civilization will eventually be able to detect you. Therefore, it is in every civilization's best interest to preemptively strike and destroy any developing civilization before it can become a threat, but without revealing their own location to the wider universe, thus explaining the Fermi paradox.

Forced by the UN's successor organization to work for them, Luo Ji is given a project to track the other probes that will shortly enter the Solar System. Project Snow is intended to create a screen across the Solar System, which when crossed will reveal the trajectories of incoming probes. Luo Ji quickly realizes the futility of this project, but throws himself into it anyway.

Three years pass, and Luo Ji falls from favor and descends into alcoholism. He travels to the grave of Ye Wenjie, the woman who first sent the message to Trisolaris and who told Luo Ji about the axioms of cosmic sociology. He digs his own grave and places a pistol to his heart. He then issues an ultimatum to the Trisolarans: He is wearing a biometric watch as a dead-man's switch, similar to one used by Rey Diaz, and has positioned the bombs of Project Snow such that they can selectively block light from the sun, creating a message that will broadcast to the galaxy the exact coordinates of Trisolaris and, by extension, Earth. The Trisolarans surrender and alter the course of their fleet to bypass the Solar System, cease the blocking of the sun as a transmission source, and agree to teach humanity how to manufacture gravitational wave transmitters.

Five Years Later

Luo Ji takes his family to visit the newest gravitational wave transmitter supported by anti-gravity. Humanity has already built 2 previous gravitational wave transmitters and all are being tasked with transmitting gravitational noise akin to that from natural space objects (neutron stars, black holes, etc.). A sophon unfolds behind them & he converses with the Trisolaran operator who first transmitted a warning to Earth. They discuss the concept of love, how Luo Ji believed only humans were capable of it and how Trisolarans were capable of it but suppressed it due to the nature of their own solar system. The possibility is brought up that love might exist in other species in the universe and thus their civilizations might have to risk the effort to preserve love in the universe. Luo Ji brings up his hope that eventually a bright sun might illuminate the entire dark forest.

Characters

• Ye Wenjie (叶文洁) – Astrophysicist who initiated initial contact between Earth and Trisolaris. Spiritual leader of the Earth Trisolaris Organization. Passes away near beginning of book.
• Mike Evans (麦克·伊文斯) – ETO financial backer and key leader, killed in previous book.
• Chang Weisi (常伟思) – General in the PLA and Zhang Beihai co-worker. First commander of humanity's space force and a defeatist who envies Zhang's Triumphalism.
• Zhang Beihai (章北海) – Political commissar in the PLA Navy. Assassinates proponents of media-drive research in order to guarantee the development of plasma drives. Appointed acting commander of Natural Selection due to a screening of fleet officers for use of the "mental seal", utilizes Natural Selection to escape the Solar System.
• Zhang Yuanchao (张援朝) – Recently retired chemical plant worker in Beijing.
• Shi Qiang (史强), also nicknamed Da Shi (大史) – Wallfacer Head of Security. Locates Luo Ji's wife for their initial meeting. Afflicted by Leukemia and hibernates to the doomsday battle with Luo Ji where he saves his life multiple times from an assassin computer virus.
• Wu Yue (吴岳) – Captain in the PLA Navy
• Zhuang Yan (庄颜) – Graduate of the Central Academy of Fine Arts, Luo Ji's wife
• Ding Yi (丁仪) – Theoretical physicist
• Secretary General Say: Secretarial General of the United Nations, oversees the creation of the Wallfacer project and selects Luo Ji, gambling that his importance to Trisolaris might generate success for humanity. Attempts to create a Human Memorial Project to catalogue human culture, which is destroyed for being defeatist by the Planetary Defense Council.
• Dongfang Yanxu (东方延绪) – Captain of space warship Natural Selection. Relieved of command due to a scan of fleet command for evidence of mental seal use, unable to prevent Zhang Behai from taking complete control of the flagship and fleeing Earth. Attempts to initiate a first strike against the other vessels due to the conclusion that there are not supplies among the ships to make the interstellar journey. Killed by a faster first strike made by Blue Space.
• Kent (坎特) – Wallfacer Security Staff for Luo Ji. Despite best efforts at physically securing Luo Ji in an underground bunker, passes on Bed Flu bioweapon to Luo Ji. Dies of old age on Luo Ji's estate.

Wallfacers (面壁者):

• Frederick Tyler (弗雷德里克·泰勒) – Former US Secretary of Defense. Primary plan was to make a massive swarm of kamakazi fighter craft to combat the Trisolarian fleet. Secondary plan was to remotely control the fighter craft swarm to betray earth and transport a massive quantity of water to the incoming fleet. Tertiary plan was to take remote control of the swarm fleet to detonate hydrogen bombs directly on the enemy fleet ships once within range. Informed by his Wallbreaker that his plan wouldn't have even scratched the fleet. Unable to resign from Wallfacer status, he commits suicide.
• Rey Diaz (雷迪亚兹) – Former President of Venezuela. Primary plan was to develop more powerful hydrogen bombs to be used to combat the Trisolarian fleet. Secondary plan was to utilize these hydrogen bombs to slow down Mercury, resulting in a chain reaction where all planets in the Solar System are consumed by an expanding Sol. Blackmails the UN with fake nuclear bombs to revoke his Wallfacer status and return to Venezuela where he is promptly stoned to death by his own people for threatening the destruction of the Solar System.
• Bill Hines (比尔·希恩斯) – English neuroscientist and former president of the EU. Primary plan was to boost human intelligence to a high enough level to overcome the scientific block on particle physics by the sophons. Secondary plan was to instill an incorruptible state of defeatism in humanity's military, forcing humanity to develop plans to escape the solar system rather than stay and fight.
• Luo Ji (罗辑) – Astronomer and sociologist. Given the initial axioms of Dark Forest theory by Ye Wenjie. Is his own Wallbreaker when he concludes that the axioms result in the Dark Forest state of the universe, and thus the only strategic option against the Trisolarians is mutually assured destruction through broadcast of their interstellar coordinates.

Trilogy

The additional books in the Remembrance of Earth's Past trilogy are:

• 三体, (The Three-Body Problem) 2008; English translation by Ken Liu published by Tor Books in 2014
• 死神永生 (Death's End), 2010; English translation by Ken Liu published by Tor Books in 2016

Videos

• Waterdrop, referring to the Trisolaran droplet probe, is a 14-minute tribute film produced by Wang Ren, who was then a graduate student studying Architecture in Columbia University. The author Liu Cixin commented, "This is the kind of film I have in mind. If the feeling of such an atmosphere can be delivered in a Three Body Problem film, I would rest in peace after I die."
• MC Three Body - The Dark Forest is an animation series produced by a group of Chinese fans. Initially a machinima series produced using the video game Minecraft, they later switched to using professional animation software. The series was released online at the beginning of 2018.

See also

• Drake equation
• Superpredator interpretation of the Fermi paradox
• 'Dark Forest' interpretation of the Fermi paradox
• Search for extraterrestrial intelligence

External links

• Official website