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''Blindsight'' is a [[MohsScaleofSciFiHardness hard]] ScienceFiction novel by Canadian author Creator/PeterWatts. It's a dark and cerebral FirstContact story that deals heavily with issues of sentience and what it means to be an "intelligent" species. Troubles with the publisher made the novel hard to find in stores, despite having been nominated for a UsefulNotes/HugoAward, so Watts put it out [[http://www.rifters.com/real/Blindsight.htm on his website]] [[DoingItForTheArt for free]].

''Blindsight'' begins soon after a global event in the near future has stunned the world. Coming to be known as the Firefall, it unequivocally demonstrates mankind is not alone in the universe: thousands of alien probes simultaneously burning up in the Earth's atmosphere in a perfect grid, seemingly scanning the entire planet, and generating a powerful radio signal sent somewhere to the outer reaches of the solar system. In need of answers that simple unmanned probes can't provide, a ship called the ''Theseus'' is built and packed with as much cutting-edge technology as its creators can muster for the purpose of carrying a manned expedition of exploration and FirstContact.

The crew is made up of odd and eccentric specialists: a linguist with [[ProfessorGuineaPig surgically-induced multiple personalities]], a biologist who has given up some of his neural pathways for [[CyberneticsEatYourSoul senses and perception far beyond what a baseline human can experience]], and an infamous soldier whose career-defining moment was [[NeverLiveItDown an act of treason]]. The narrator, an analyst with [[EmptyShell half his brain removed]], is sent to observe these transhumans and translate for the benefit of their earthly masters. And they are all led by a literal [[OurVampiresAreDifferent Vampire]]; a genius, sociopath, and [[ImAHumanitarian cannibal]] who is nevertheless the only one coldly-logical enough to run the mission.

Depressing and pessimistic, yet enlightening, the story explores a variety of topics relating to consciousness, the nature of intelligence, information theory, and neurology, and has received highly positive critical acclaim despite its relative obscurity. It is followed by ''Literature/{{Echopraxia}}'', a loose {{Sequel}} set on Earth during the events of ''Blindsight'', featuring a different cast of characters.

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!!This book features the following tropes (Warning: spoilers below):

* ActionGirl: Amanda Bates, the awakened military portion of the crew.
* AIIsACrapshoot:
** [[spoiler:The Theseus AI is in command of the mission, but acts through Sarasti specifically because humans wouldn't trust an AI to give them orders]].
** Discussed by Szpindel and Siri, regarding the combat drones Bates commands, and again averted - the drones actually operate more efficiently when they're allowed to run autonomously.
* AmbiguousSyntax: Intentionally used in-universe in the dialog with ''Rorschach'' to see if they really understand or are just using sophisticated translation algorithms to parse the syntax. They conclude that it's a Chinese Room, though the matter is left as an open question. [[spoiler: While it's a question that was never definitively answered, considering what it believes humans were doing, it's likely that ''Rorschach'' believed that it was trading confusing statements to conduct "information warfare" to keep the ''Theseus'' away long enough to finish germinating]].
* {{Antimatter}}: ''Theseus'' is powered by an anti-matter engine. This becomes important later when [[spoiler:it's used as a bomb in Jukka's final TakingYouWithMe action against Rorschach]].
* AllThereInTheManual: The back of the book has a "Notes and References" section that fleshes out some of the more radical ideas in the novel. Watts's website also provides supplementary information, including a [[http://www.rifters.com/blindsight/vampires.htm fictional in-universe audio log and powerpoint presentation]] of a scientist presenting his findings on the vampire sub-species to his "[=FizerPharm=]" investors.
* AntiMutiny:
** Amanda Bates's career defining moment came when she interrupted an interrogation session of Realist terrorists, and allowed the single survivor to execute his/her interrogators - Bates's own subordinates.
** For context, it was inferred that the interrogators knew that they couldn't get useful information from their captives, they were just raping, torturing, and killing those captives because they thought it would be fun, war crimes be damned. While Bates technically committed an act of treason, this unsanctioned act of empathy gave Bates a diplomatic line that resulted in radically reducing terrorism incidents in the region, and the results reversed Bates's court martial and expedited execution to her being hailed as a hero (no matter how much the brass hated it). She was [[ReassignedToAntarctica transferred to the Theseus]] as a special assignment, but it's an open secret that the brass just didn't want to have to deal with her.
** Siri reads that [[spoiler: she's planning on mutinying on Sarasti because he's starting to show signs of instability, such as torturing the captured Scramblers and brutalizing Siri]]. This later comes to a resolution [[spoiler: when Sarasti tells Siri that Bates is planning no such thing, and that Siri was reading into the matter his own personal opinion that Sarasti should be replaced]].
* AnyoneCanDie: Considering Watts' past work, and since the novel is very dark and pessimistic, this is a given. [[spoiler:Everyone except the narrator dies, and the narrator thinks that humanity back on Earth is doomed as well, one way or another.]]
* ApocalypseHow: [[spoiler:On the long, long, lonely flight home, Siri is getting messages that imply the breakdown of society in the inner solar system. By the writing of this book, it would suggest that all the troubles at home have finally come to a head. He believes that by the time he returns to Earth, the inevitable result of what's going on in the inner system is that vampires will have exterminated humanity and taken their places as the owners of the world.]]
* AttackDrone: Commanded by Bates, who insists on personally inspecting every newly-fabricated drone.
* BaldWoman: Amanda Bates. Her head was likely shaved, since she's still technically a member of the military.
* BeingHumanSucks: In the world of ''Blindight'', baseline humans are obsolete. Some go {{Transhuman}} to keep their edge, but even the engineered superhumans can't compete with the newly-resurrected vampires. [[spoiler: And not only that, but humans were defective to begin with - ''self-awareness'' is holding us back.]]
* BizarreAlienPsychology: One of the book's twists is [[spoiler:the discovery that humanity is pretty much the only race out there with a concept of self, reason and such things as art... which the aliens see as an abomination of infection and have decided to eliminate humanity because it hurts them]].
* BigDumbObject: ''Rorschach.'' Although the "dumb" part is debatable, and indeed is debated throughout the book.
* BlueAndOrangeMorality:
** The aliens [[spoiler: don't just think in a way incomprehensible to humans. They're not even self-aware. Morality is a concept that is so impossible for them to parse that just trying to communicate it is seen as an aggressive act.]]
** Jukka Sarasti and the rest of the resurrected vampires. Sociopathic cannibals operate on a rather different wavelength than the rest of us.
* BrainInAJar: On Earth, a lot of people have plugged themselves into Heaven, a virtual reality that few choose to return from. While Heaven's managers insist the entire body is kept intact and in peak fitness in case of emergency, Siri suspects this trope is the actual case the second a person's family is barred from visiting them.
* BrownNote:
** Vampires, because of their unique spatial reasoning, get seizures when they see too many right angles. It gave rise to the myth that they're vulnerable to crosses, but the truth is they short out if they see something as simple as a window pane or a building with a square footprint. They largely went extinct after the invention of architecture in early human history.
** Vampires themselves can make noises that are this for normal humans, believed to be due to ancestral memory. They make hissing and clicking noises that subliminally remind humans that they were prey creatures on the African plains not all that long ago.
** The ''Rorschach'' emitted an extremely powerful, whirling magnetic field several times more powerful than that of the sun, though it's not certain how. Boarding the thing could induce radiation sickness in mere hours, and constant low-level hallucinations immediately, and intense hallucinations when the magnetic field surged.
* CallingParentsByTheirName: Siri refers to his mother in the flashbacks as "Helen". In a large part because she ditched the real world for virtual reality. While he often calls his father "Dad", and "Jim" other times.
* CameBackWrong: In order to cure his epilepsy and save his life, Siri's parents agreed to have a radical hemispherectomy performed on their son, literally cutting out half his brain. The kid that came out on the other side is demonstrably not the same: emotionless and without natural empathy. Siri thinks back to what his life was like, pre-op, and the memories feel like they belong to someone else.
* CannonFodder: When the crew has no other option but to go explore ''Rorschach'' in person, Siri has no illusions about his role in the enterprise.
---> Three valuable agents in harm's way. My presence bought one in four odds the enemy would aim somewhere else.
* TheCaptain: Jukka Sarasti, the vampire. It's later revealed that [[spoiler:the ship itself, the Theseus, is artificially intelligent and was the ''real'' captain the whole time]].
* TheChessmaster: The book deals with entities that are orders of magnitude more intelligent than the average human, so this is almost a given.
** Sarasti, like all vampires, evolved to hunt humans. No matter how hard you try to out-maneuver him, he'll always be one step ahead of you. Waiting. He was sent on the mission for this exact purpose - "vampire logic" might give ''Theseus'''s crew the edge they need against ''Rorschach''.
* ColdBloodedTorture:
** In the "Imagine you are prisoner of war" segment, intelligence agents torture and kill a few captured "[[WellIntentionedExtremist Realist]]" terrorists for fun. Bates did not approve, and decides to give the surviving terrorist [[DoWithHimAsYouWill a bit of payback]] as a gesture of good faith.
** [[spoiler:When the crew finally capture a pair of Scramblers:]]
---> "This is how you communicate with a fellow intelligence: you hurt it, and keep on hurting it, until you can distinguish the speech from the screams."
* CoolStarship: ''Theseus''. Hyperintelligent AI? Check. Antimatter engines? Check. Fabrication units that could put the replicators from ''Frachise/StarTrek'' to shame? Check.
* CorruptCorporateExecutive: [[http://www.rifters.com/blindsight/vampires.htm FizerPharm]] in the book's supplementary backstory.
* TheCorruption: The supplementary material for the novel on Watts's website reveals that first resurrected vampires arose during an experimental autism treatment that used retroviruses to deliver genetic modifications to patients. Whether the result could reasonably be called a "cure" for autism isn't really clear, but the thing that comes out of the other side of the treatment can certainly be said to be [[GoneHorriblyRight terrifyingly high-functioning]].
* CosmicHorrorStory: ''Blindsight'' deals primarily with characters that display psychopathic or sociopathic traits, and is set in a future in which the basic human sense of worth is undermined by the social implications of new technologies. But the true cosmic horror is not revealed until near the end of the story, as it's revealed that Watts is portraying a universe in which [[spoiler: sapience (that is, self-awareness, sentience, and the empathy that goes with it) is unnecessary for advanced intelligence and creative thinking. In fact, it's ''inefficient'', tending to lead to Solipsism and wasting resources on pointless endeavors like art. Apparently most other species in the ''Blindsight'' universe may not be sentient at all, despite possessing vast intelligence and the ability to travel the distances between stars.]]
* CrapsackWorld: The short version is that mankind hit TheSingularity... and it didn't really take. If the bastardized technological world doesn't kill us, the superintelligent sociopath vampires [[WhatCouldPossiblyGoWrong we brought back to life with our genetic prowess]] and ''[[TooDumbToLive put in charge of everything]]'' will. And if ''they'' don't... well, the novel is about how we just met an intelligent alien life vastly superior to our own single planet existence and it very may well want to '''wipe us out'''.
* CruelAndUnusualDeath: The "Golem" virus induces rapid [[http://en.wikipedia.org/wiki/Fibrodysplasia_ossificans_progressiva Fibrodyplasia Ossificans Progressiva]], a particularly horrible condition that causes tendons, ligaments and muscles to turn to bone, effectively petrifying you. There's no cure, and slowing it down just means you die in a couple of days instead of just one. It's used as a biological weapon, and is what kills [[spoiler:Chelsea]].
* CyberneticsEatYourSoul: Isaac Szpindel's mechanical augments let him interface directly with the ship's labs - giving him all the senses that implies - but his own normal senses have been so numbed that he has to wear force-feedback gloves just to give him a sense of touch. Despite this, Szpindel is one of the most personable and emotionally stable members of the crew. [[spoiler: Cunningham, Isaac's replacement]], gets around this by using the neurons that control his face instead.
* DeathIsCheap: This is what allows the crew to explore Rorschach. Body riddled with tumours? The ''Theseus'' has the facilities to let you sleep that off. [[spoiler:Unfortunately for Szpindel, you can't sleep off a gaping head wound.]]
* DeerInTheHeadlights: To look into a vampire's eyes is to remember what it's like to be prey.
* DoingInTheWizard: In the novel, Vampires are not supernatural but rather are explained as an extinct subspecies of humans that evolved to prey on normal humans in ancient times. This explains the persistent myths and stories about them: these are a kind of racial memory. Many of the qualities of Vampires are given logical, scientific explanations as well. See OurVampiresAreDifferent below.
* DownerEnding: [[spoiler:Nearly all the characters in the novel end up dead or soon to be dead, and it's implied that humanity back home on Earth is doomed by a vampire uprising]]. In a more general sense, [[spoiler:we've discovered that humanity is an aberration in a cold, uncaring universe]].
* EldritchAbomination: ''Rorschach'', an alien construct in close orbit around a brown dwarf hidden in the Oort Cloud. It looks like a jagged torus, compared to a crown of thorns, and is rapidly growing, apparently by absorbing material from the planet's ring. It's also emitting an extremely powerful, whorling magnetic field, strong enough to induce radiation sickness and hallucinations in any humans who board it. What it is exactly isn't established concretely, though it's speculated to be a ship, an AI, a living being, a form of [[RecursiveCreators Von Neumann machine]], or some combination of the above. [[spoiler: While it's incredibly intelligent, it's so alien that it's not even self-aware.]]
* EldritchStarship: Once again, ''Rorschach''.
* EnemyWithin: Rorschach makes some changes to [[spoiler:Susan James]], as one of many simultaneous plans to deal with the inconvenient humans.
* EssentialMadness: The main character's severe autism-like condition means he's the only one able to [[AwesomeByAnalysis objectively analyze]] all of the information and determine just what the deal is with the {{Starfish Alien}}s they discover. Of course he's also unable to bond with other people or empathize with them, so...[[BlessedWithSuck downer]].
** The predatory instincts and complete sociopath nature of the ship's captain (who is an actual vampire) also turns out to be vital in second-guessing the otherwise indecipherable behaviour of the alien vessel and its inhabitants.
* FirstContact: The reason why ''Theseus'' is manned at all. The ''Theseus'' is actually the "third wave" for analyzing the object that started Firefall, the first wave being a pair of probes sent out to get eyes on the object, and the second were more sophisticated drones meant for analytical work.
* FiveManBand: In a twisted, unusual way, but it's there.
** TheHero: Siri, as the narrator, despite his policy of noninterference.
** TheLancer: Isaac Szpindel, biologist with extensive cybernetics, and the friendliest towards Siri.
** TheSmartGuy[=/=]TheLeader: Jukka Sarasti, who is frighteningly intelligent, like all [[OurVampiresAreDifferent vampires]], that the average human is incapable of understanding how he reaches his conclusions.
** TheBigGuy: Amanda Bates, the military officer.
** TheChick: Susan James (in her core personality), though she also has elements of TheSmartGuy. Furthermore, the rest of the Gang play different roles.
** SixthRanger: [[spoiler:Cunningham]]
* ForgettableCharacter: [[spoiler: The Captain]]. Never communicates, [[spoiler: except through Sarasti]], to the point that the others tend to assume he's the one in command, and basically treat the title as an ironic nickname. Near the end of the book [[spoiler:is the first time Siri even [[OOCisSeriousBusiness hears the Captain's voice]].]]
* GeneticMemory: Humans are thought to be naturally, automatically, and helplessly ''freaked out'' when they encounter a vampire due to genetic memory of being hunted by them. [[spoiler: It turns out that vampires are smart and fast enough to intentionally trigger hallucinations and fear responses using subtle nonverbal cues]].
* FlingALightIntoTheFuture: [[spoiler:This is what ''Theseus'' and the rest of the crew has in mind when they send Siri back toward Earth on board one of the ship's shuttles. Siri realizes en route that it's not going to work - there might not be anyone left by the time he gets home.]]
* {{Hallucinations}}: ''Rorshach's'' incredibly strong magnetic fields induce some rather vivid and disturbing visions in the crew when they venture inside. Siri sees alien beasts out of the corner of his eye, James thinks her leg ''needs'' to be detached, and Bates at one point believes she doesn't exist.
* HeroicSacrifice: [[spoiler:The entire crew of the Theseus, except for Siri.]]
* ImprovisedCross: Exaggerated, justified, and deconstructed. Vampires have the vertical and horizontal crosswired in their visual cortex, which causes them to suffer fatal seizures upon seeing perpendicular lines. As would be expected, they went extinct when humans invented architecture.
* InscrutableAliens: A variant. The alien ship does make contact, but for hours talks in circles without revealing any useful information. The crew come to the conclusion that they're talking to a [[http://en.wikipedia.org/wiki/Chinese_room Chinese room]].
* InsideAComputerSystem: People have started to transfer their minds into a computer system called "Heaven." The Realists terrorist group are trying to destroy it.
* IntrepidReporter: Siri's original job on the ''Theseus'', in a nutshell. He's a "synthesist" by trade, a sort of analyst who's good at translating impenetrable technical information into something more digestible to a (slightly) more general audience. Though his job is based more on mastery of communication theory and understanding how to shift information between frames of reference, not on understanding the information he's presenting. On the ''Theseus'' he was meant to be a neutral observer going over the crew's findings and relaying it back to Earth, though circumstances didn't exactly pan out.
* ItCanThink: [[spoiler:The crew puzzles over whether the scramblers are intelligent aliens or something more like white blood cells in the organism of ''Rorschach''. They eventually figure out that the scramblers are ''far'' more intelligent than humans, but they are nonsentient, as is ''Rorschach'']].
* LastOfHisKind: [[spoiler:On his long, long trip back toward Earth, Siri reflects that he may be not only the last human, but also the last sentient being in the universe. Talk about a DownerEnding.]]
* LovePotion: In a flashback, Siri remembers his mother secretly gave him stimulants to promote mother/child bonding. It didn't really work.
* ManchurianAgent: [[spoiler:Susan's fifth personality.]]
* MagicFromTechnology: Invoked at one point.
--> Bates spread her hands. "Who knows? Might as well be black magic and elves down there."
* MindHive: The Gang Of Four are distinct personalities that inhabit the body of Susan James. Unlike Multiple Personality Disorder, the fictional "Multiple Core Complex" is done ''deliberately'' and lets a fairly standard human brain run as many as two dozen distinct minds, each capable of thinking independently and communicating with the others. In co-operation they can be a formidable force.
* MyBelovedSmother: Siri's relationship with his mother, Helen. After his operation, she became increasingly desperate for her son to simply respond to her, causing her to become increasingly invasive and even manipulative towards Siri. The results were that it eventually strained his parents' relationship to the breaking point, she eventually withdrew from the world and plugged into Heaven, and his negative relationship with his mother helped shape Siri's view that humanity are fundamentally irrational, instinct driven creatures. The last one had a major negative impact on his relationship with his girlfriend Chelsea.
* MythologyGag: One of the chapter headers has a quote from the fictional book called ''Zero Sum'', written by "Kenneth Lubin". Lubin is a character in Watts' Literature/RiftersTrilogy.
* NeverSplitTheParty: On one expedition into ''Rorschach'', Bates orders the crew to split up and cover more ground, though they each get their own combat drone for a bodyguard. [[spoiler: Not that it helps all that much when Siri has his first run-in with one of the aliens.]]
* TheNicknamer: Szpindel dubs Siri "[[PoliticalOfficer Commissar]]" early on in their training, and refers to Amanda Bates and Michelle (one of Susan's personalities) as "Mandy" and "Meesh", respectively.
* NotSoStoic: Siri quickly loses his detached demeanor after [[spoiler:he's mauled by Sarasti.]]
* NothingIsScarier: The crew's first few expeditions into ''Rorschach''. Siri expects to be nabbed by a horrible alien monster at any second, and yet the place seems to be deserted, yet still creepy as all hell. The hallucinations induced by the magnetic fields in there don't help matters. [[spoiler: Turns out the crew had been encountering the scramblers longer than they think. Scramblers can turn "invisible" because they can ''see'' the neurons in the eyes firing, and use this information to exploit a glitch in the human visual system, though they can't fool cameras or multiple witnesses. Siri somehow intuited what they looked like before he ever saw one.]]
* OurVampiresAreDifferent: Vampires turn out to have been an ancient HumanSubspecies adapted to prey on us. They existed millennia ago, before recorded history. Since they were predators, they had to have superior pattern-matching skills (all the tricks of autistic savants plus more) and general intelligence, better night-vision and the ability to put themselves into suspended animation (since, being apex predators, they had to give our populations time to rebound else they would hunt us to extinction). Unfortunately, the super-intelligence comes at a cost: their super-charged pattern recognition tends to get overstimulated when [[WeaksauceWeakness intersecting right-angles take up too much of their visual field]]. Basically, their brain ''glitches out'' and they have [[BrownNote epileptic seizures]] whenever they see anything with corners - thus explaining the origin of [[CrossMeltingAura the myth about them being weak against the cross]]. When humans invented architecture, the vampires all died out. The modern-day resurrected vampires have to take "[[AppliedPhlebotinum Anti-Euclidean]]" drugs to enable them to survive because geneticists weren't stupid enough to remove the weakness.
* PatrickStewartSpeech: {{Inverted}}, Sarasti gave a lengthy speech [[spoiler: going on the weakness of sapience. This wasn't a TheReasonYouSuckSpeech, but to emphasize to Siri humanity's precarious position in the universe, and why he needed to convey that message when he was sent back]].
* PosthumousCharacter: [[spoiler:Siri's girlfriend Chelsea.]]
* RagtagBunchOfMisfits: The ''Theseus''' crew.
** Siri Keeton's hemispherectomy lead to resemble being highly autistic, albeit quite high-functioning.
** Isaac Szpindel, [[spoiler: and later his replacement as well, Robert Cunningham,]] is a biologist studded with cybernetic sensors that allows him synesthesiac perception of the world in great detail, though gives tremors and reduced senses to the original flesh. [[CyberneticsEatYourSoul Opposite of what would be expected]], Szpindel is also the most personable and good-humored member of the crew. [[spoiler: Cunningham can be a bit of a dick and smokes constantly (nicotine steadies the tremors, but the antiquated delivery method is a personal affectation), though he is a dedicated worker and never drops into unprofessionalism.]]
** Amanda Bates is the one approaching normal, though she's a military officer who made an unsanctioned act of diplomacy which included a minor act of treason as a "good faith measure", though it got better results in months than raw military actions. [[ReassignedToAntarctica She was stationed on the ship]] as security, but [[spoiler: privately considers staging a mutiny against Sarasti]]. And yet, [[spoiler: [[RedHerring that last part was all in Siri's head]].]]
** Susan James, a linguist with her brain surgically partitioned off to produce three other multiple personalities and a number of shared subconscious nodes (each a skilled linguist in their own right, and collectively called the "gang of four" or "the gang"). Susan is notably soft-hearted but won't shirk hard duties. Her alternates are Michelle, a sweet woman who's in a relationship with Szpindel, Sascha, a rude and foul-mouthed woman, and Cruncher, a ''man'' who's a frank and irritable workaholic.
** Jukka Sarasti, the sociopathic and predatory leader who can think circles around the entire group.
** And finally [[spoiler: the Captain, the ship's onboard AI, who has few real defining traits, but it piggybacks onto Sarasti's cybernetics for a low-key presence among the crew]].
* RedHerring: There are several, both in-universe and as a narrative device. [[spoiler:For example, there is the issue of Amanda Bates' planned mutiny against Jukka Sarasti, the messages from Rorschach, the Burns-Caulfield comet, and the very nature of the UnreliableNarrator.]]
* SelfDeprecation: A meta-example comes later in the book, where "the occasional writer of hackwork fiction who barely achieved obscurity" is listed amongst those who wondered about the [[spoiler:necessity of conscious thought.]]
* SherlockScan: Siri can look at you and tell, based on the way you slouch, your innermost thoughts and fears, whether you were abused as a child, and who your favorite painter is, all in the span of a few seconds. Cunningham suspects that his hallucination of [[spoiler:the aliens onboard the ''Rorschach'', before actually seeing then, were his subconscious mind trying to get the information out somewhere useful.]]
* {{Shoutout}}:
** One of the chapter header quotes is "What doesn't kill us makes us stranger," attributed to Trevor Goodchild, of ''WesternAnimation/AeonFlux''.
** [[http://www.rifters.com/blindsight/vampires.htm A Flash presentation set in-universe]] describes the various physiological and mental characteristics of vampires, and gives their binomial as [[Series/BuffyTheVampireSlayer ''homo sapiens whedonum.'']] The book itself gives a different binomial.
* ShownTheirWork: The back of the book has a lengthy bibliography with 133 references.
* SleeperShip: The crew were all modified with vampire hibernation genes so they could sleep through the five-year voyage to the alien ship in the Oort Cloud.
* SociopathicHero:
** The protagonist Siri has shades of this. He's not a clinical sociopath, but his hemispherectomy left him largely unable to feel emotion and empathy. His coldly clinical view of the world allows him to understand people's thinking, but that doesn't change the fact that he just doesn't ''get'' people. Many of his personal biases come from the fact that he can't properly understand emotional context or relate to people.
** Jukka Sarasti, the commander of the crew. He is the one somewhat-reassuring ace-up-the-sleeve the crew has in the face of [[spoiler:the incomprehensible EldritchAbomination that is ''Rorschach'']]. He is even (superficially) considerate to his crewmates by choosing to wear sunglasses, in deference to the uncontrolled primal fear they would feel if they looked directly into his eyes. Ironically, towards the end of the novel we learn [[spoiler:the true captain of the ship is the ''Theseus'' [=AI=], whose creators assumed that the human crew would rather take orders from a Vampire than listen to a computer.]]
* SplitPersonality: Purposefully [[InvokedTrope invoked]] by Susan's "Gang of Four". Susan is the core personality, and the others were surgically induced to allow them to translate languages at incredible speed through parallel processing.
* StarcrossedLovers: Siri's relationship with his girlfriend Chelsea, which get's brought up in flashbacks. Chelsea was a rather old-fashioned GirlNextDoor who was fascinated by Siri's honesty and how his condition gave him a unique outlook on the world, and he appreciated her honest affection and optimistic outlook. However, Siri's lack of empathy makes it obvious he just doesn't have a good grasp on his humanity, combined with BrutalHonesty made him unable to be a functional boyfriend, which destroyed their relationship after a time.
* StarfishAliens: The Scramblers are among the best examples of this trope.
** Physically, the scramblers resemble starfish and share a few of their traits. Peter Watts, a former marine biologist, admits to this.
** [[spoiler:It's implied that their alien way of thinking is actually the status quo in the universe and that human self-awareness is an aberration. The Scramblers picked up our various transmissions from Earth and, after decrypting the signals, get incomprehensible (to them) statements about "feelings" and "identity". From their perspective, since they lack sentience, they assume the only reason to broadcast things like that to somebody is to ''waste their time''; they see this as tying up vital processing power. As such, this appears to them as a kind of ''attack'' by us. So the aliens decide to strike back. Self-awareness itself that which makes us human is seen by the aliens as a dangerous virus to be stamped out.]]
** It's left ambiguous to what extent [[spoiler:which of the Scramblers vs. ''Rorschach'' that are/is the actual alien "lifeform", and which is the construct, or whether it's both, or neither]], or to what extent this is a meaningful distinction (the sequel hints that [[spoiler:they can create entirely new "species" tailored to an invasion, so nothing we see really confirms anything about ''Rorschach's'' creators]]). At any rate human notions of identity definitely do not apply.
* TakingYouWithMe: [[spoiler:Jukka Sarasti/Theseus' final strategy against ''Rorschach''.]]
* TitleDrop: "Blindsight" is a real-life phenomenon where blind people, assuming their actual eyes are not damaged, can sometimes avoid obstacles despite not being able to consciously see them. Some part of their brain is still processing visual input despite the normal vision part of the brain being damaged. In the novel, this is used [[spoiler:as a metaphor for the distinction between conscious and unconscious mental processing. The characters experience a kind of blindsight when their cognition is impaired by ''Rorschach'''s powerful magnetic fields. The Scramblers are suspected to be non-sentient beings for whom ''all'' sensation is blindsight. Vampires are implied to be similarly evolving toward non-sentience. And the fundamental horror of the novel rests in the final implication that non-sentient, unconscious cognition is evolutionarily superior and will dominate in the universe. Human awareness is portrayed as inherently self-destructive, as evidenced by the creation of the solipsistic cyberspace "Heaven".]]
* TooDumbToLive: [[spoiler: All of humanity. Why don't we bring back our ancient predators and put them in charge of everything since they're so smart?]]
* TranslationConvention: The narrator mentions the crew speaks a multilingual patois they find more exacting, but it's translated for our convenience. The exception is Susan James, the linguist, who the protagonist trusts to speak for herself, though not necessarily the rest of her personalities.
* TroublingUnchildlikeBehavior: Siri, after his childhood operation. He loses all understanding of social norms, most of his emotions, and his sense of empathy. After rescuing his friend Pag from a group of bullies in the prologue - [[DisproportionateRetribution by bashing a few of them in the head with a large rock]] - and seeing one on the ground trying to crawl away, he wonders in a detached way if he should "kill it before it gets reinforcements". He was eight years old at the time.
* {{Tuckerization}}: Some of the characters are named after friends of the author who provided some sort of assistance.
* UnreliableNarrator: [[spoiler: Siri isn't as objective as he believes. Though there's probably an element of truth to his perceptions, he projects his personal biases onto other. He believes the others dislike him, because Siri is unhappy with what he's become over the years; and he believed Bates was planning a mutiny, because he felt Sarasti should be removed from command.]]
* VerbalTic: Szpindel ends every other sentence with '[[CanadaEh eh]]?'. The author is Canadian.
* ViewersAreGeniuses: But the uneducated reader forcing themselves through it will learn many interesting things, guaranteed. With this expectation, Watts includes a lengthy citation section that references the most bleeding-edge theorists and scientists in many fields, for follow-up if you've recovered from the book itself.
* WarriorTherapist: Near the climax of the plot, Sarasti viciously beats down Siri. The reason for doing so appeared to be to [[spoiler: invoke fear and pain, to demonstrate that for all of his pretenses of being detached from his humanity, and being the impartial observer, Siri simply isn't those things. And that it was the opening statement to Sarasti's [[{{Inverted}}anti]]-PatrickStewartSpeech]].
* WeaksauceWeakness: The vampire's classic weakness against the cross is discovered to be a weakness against ''anything'' with intersecting right angles. See OurVampiresAreDifferent.
* WhamLine: The scene where Sascha and Siri figure out what they're really facing is probably one of the most hair-raising Wham Lines to be found in science fiction. [[spoiler: That humans are probably the only sapient life in the known universe. Most aliens are intelligent but nonsentient. Not only are they better adapted to survive because of it, but they would see humanity as a natural enemy because humananity ''[[HumansAreCthulhu is just that alien]]''.]]
* WhatYouAreInTheDark: Siri. Much of his character arc stems from that he believes himself to be an objective observer, both by trade and because his nature doesn't permit him to be much more. He believes he's essentially a form of sapience without much humanity left to him. [[spoiler: Contrasted to ''Rorschach'' and the scramblers, who are extremely intelligent but non-sentient--about as inhuman as you can get--Siri eventually comes to terms with the fact that he has more humanity than he thinks, and the fact he is sapient means that he's not ''quite'' as objective as he would like to be plays.]]
* WrongGenreSavvy: A few of the characters, at different times, make the mistake of assuming theirs is a fairly standard tale of FirstContact. [[spoiler: It takes some longer than others to realize the reality is closer to a CosmicHorrorStory ...]]
* YouNoTakeCandle: A number of characters have linguistic quirks that would by normal standards be considered improper - Cunningham, for example, can't use pronouns, referring to everyone as "it", while Sarasti avoids using the past tense when speaking, and whose brain is possibly wired in such a way that he can't even conceive of the past in the way normal humans do.
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