->''"The kind of classic fifties-era [[FirstContact first-contact]] story that Creator/JonathanSwift might have written, if Jonathan Swift had had a background in game theory."''
-->-- '''Peter Watts''', "[[http://www.rifters.com/crawl/?p=266 In Praise of Baby-Eating]]"

''[[http://lesswrong.com/lw/y4/three_worlds_collide_08/ Three Worlds Collide]]'' is a [[RationalFic rational]] [[WebSerialNovel web novella]] by EliezerYudkowsky of the [[MohsScaleOfSciFiHardness semi-firm SF variety]]. As previously mentioned, it is a FirstContact story - it deals with the ethics and tactics associated with meeting StarfishAliens, among other things. To some extent it also reads like a thought experiment about game theory (it was, after all, written for [[LessWrong a blog about human rationality]]). Has many allusions to [[MemeticMutation modern Internet memes]] and current ideas in the [[{{Transhuman}} transhumanism]] community.

Also, swearing, naughty tentacles, and other stuff which [[NotSafeForWork your boss might not like]].
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!!The story provides examples of:
* {{Aesoptinum}}
* AuthorTract: Much of what transpires is an illustration of theories the author had previously posted to the same blog. See ''FanFic/HarryPotterAndTheMethodsOfRationality'' for another example.
* BeautyEqualsGoodness: Inverted and played straight. The Babyeaters are elegant crystalline things, yet they based their entire culture on the slow, painful consumption of their own sentient offspring. However, the ''even worse'' "Super-Happies" are utterly disturbing blobs of tentacle and colour.
* BewareTheNiceOnes: The wrath of the Superhappies is terrible indeed. Terrible and weird.
* BlueAndOrangeMorality: The entire point of the story.
* BoldlyComing: The Superhappies first-contact message ends with "[[DoYouWantToCopulate Would you like to have sex]]?"
* CultureClash: A fairly extreme one at that.
* DeathbedConfession: The Confessor [[spoiler:admits that he once raped and killed a young woman when he was young, and that he also had fetal alcohol syndrome.]]
* DeathEqualsRedemption
* DeliberateValuesDissonance: Future social mores aren't like present ones, much like present ones aren't like those of several hundred years in the past. A particular example is future humans' views on [[SexualHarassmentAndRapeTropes rape]], which are so divorced from modern mores that the latter are incomprehensible to the protagonists even after being explained.
* EarnYourHappyEnding: The author made the ''readers'' earn it.
* EarthShatteringKaboom
* EatsBabies: Subverted and ''inverted'' by the [[ExactlyWhatItSaysOnTheTin Babyeaters]] -- not only is the EatsBabies trope ''not'' used as a simple sign of being evil, but in the Babyeater fiction, letting too many babies live ''is'' used as a simple sign of being evil.
* EsotericHappyEnding: Deliberately invoked -- either or both endings could be considered this, depending on your values. According to the author, the ending that involves [[spoiler:killing billions of humans]] is the ''good'' one.
* FirstContact: A triangular example between Humans, Babyeaters, and Superhappies all at the same time. Justified by all three races having been attracted by an unusual cosmological phenomenon in the vicinity.
* GallowsHumor: One of the main coping strategies of many characters in the last chapter.
* GeneticMemory: Also sexually transmitted.
* GettingSmiliesPaintedOnYourSoul: What the Superhappies plan to do to the Babyeaters and humans.
* GoldenEnding: After being told to EarnYourHappyEnding, the readers came up with a plan that was even better than the best one the writer had considered.
* GroinAttack: Played for humor.
* HappilyEverAfter: The ''bad'' ending. For certain values of "happily".
* [[spoiler:TheHeroDies]]
* HumansAreAverage: Surprisingly, given how strange the aliens are, the Supperhappies stand in the same relationship to humans that humans stand to the Babyeaters.
* HumansThroughAlienEyes
* {{Infodump}}: I've translated the aliens' language! But before telling you what they said, let me bring you up to speed on the history of statistical language-translation methods...
* IntentionalEngrishForFunny: The humans' translation software isn't perfect, but it gets better over time. Also, some ridiculous-sounding statements that the characters assume were garbled in translation were, in fact, translated correctly.
* InTheFutureHumansWillBeOneRace: Implied.
** And, in one ending, [[spoiler:"In The Future All Life Will Be One Race."]]
* JustInTime: [[{{Deconstruction}} Deconstructed.]] [[spoiler:They kill ten billion people because of the unknown risk that the aliens might otherwise show up in time, which there is little real basis to think would happen. Waiting six hours would have saved them. This is the correct decision. Some of the ships that are evacuating as many people as they can don't leave in time and get fried by the supernova.]]
* KilledMidSentence: The third ending, "Atonement".
* LanguageEqualsThought:
** The Baby Eaters use the same word for "to eat babies" and "to be moral". This makes it rather difficult for the humans to explain that they consider baby-eating ''not'' to be moral.
** The Superhappies use the same word for "to talk" and "to have sex", because they think and communicate by exchanging genetic material, which means talking and having sex are literally the same act to them.
* MeaningfulName
* MentalAffair: The "Superhappies"
* MentalFusion: Again, the "Superhappies"
* MindlinkMates: The "Superhappies" yet again
* MrExposition: Each character functions in this role at least once.
* MultipleEndings: Including interactivity - the author announced at the split point that the true ending would be determined by whether anyone came up with the correct solution in the comments to the post before the critical update.
* NotSoDifferent: "They're a lot like our own children, really." [[spoiler:That is, not only are the Babyeater children like human children, ''human'' children are like ''Superhappy'' children ... and the Superhappies feel as much revulsion for how humans treat their children as humans do for Babyeaters eating their children alive.]]
* OlderThanTheyLook: The humans have developed biotechnology which is implied to allow them to live forever.
* PortalNetwork
* RealityEnsues: Regarding FirstContact.
* [[spoiler:ShootTheDog]]: All three endings have this.
* ShoutOut: "The aliens will consider this one of their great historical works of literature, like {{Hamlet}} or [[FateStayNight Fate/stay night]]..." The Superhappies also have a ship officer with the rank "kiritsugu" which is the family name of a major character from [[FateZero Fate/Zero]] who had a background role in [[FateStayNight Fate/stay night]].
* StarfishAliens: Including a GrotesqueGallery. Could be considered a {{Deconstruction}} considering just exactly ''how'' different the aliens are.
* UniversalTranslator: [[JustifiedTrope Justified]]. The aliens send them an entire copy of the ''internet'', and the humans use statistics to match up languages.
* ValuesDissonance: InUniverse -- the plot is "Future Humans" (as different from us as a typical alien race from more typical scifi) make first contact with two utterly alien species at the same time. Then the Human command crew spend twenty-four hours discussing ValuesDissonance.
* WhatIsThisThingYouCallLove [[XMeetsY meets]] HumansAreCthulhu: "What is 'untranslatable 2'?"
* WhatYouAreInTheDark: The trope is discussed in the epilogue by the main cast, after they [[spoiler:trigger the supernova at Huygens]].
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