You Cannot Kill an Idea

"A man may die, nations may rise and fall, but an idea lives on. Ideas have endurance without death."

— John F. Kennedy

What is the most resilient parasite? An idea. A single idea from the human mind can build cities, rewrite all the rules, and transform the world. Neither armies, nor dictators, nor even mortality have power over them; people die, but their ideas do not.

In fiction, we get heroes dying but hope passed onto the audience by knowing that somehow his idea has lived on. Sometimes the hero is a martyr and his death is a beginning as people use it for inspiration; they are throwing off some kind of mind-breaking torture attempt to show that the forces of fascism can't control them. A book of philosophy or some diary may have survived him, or one of his inner circle may tell his tale and so the story ends on a happy note, but not too happy. Our story is sad, but the tide of inevitable revolution will come.

The Trope Namer is World War II veteran and American civil rights activist Medgar Evers, who stated that "you can kill a man, but you can't kill an idea." He was later shot dead by a Klansman, but the Civil Rights Movement endured.

Super-Trope of Can't Stop the Signal. The characters who pass on the idea are likely Doomed Moral Victors. Likely to inspire an Innocent Bystander to make a Defiant Stone Throw. Compare We Are Everywhere for those bad ideas that can't be killed, As Long as There Is Evil for evil in general that can't be killed, and Mind Virus for bad ideas that deserve to die but are too sentient and/or too contagious to be killed by law of morality, man or God (and don't expect Time Travel or Villainous Rescue to fix it either). Compare the Streisand Effect. See also As Long as There Is One Man.

---

Examples:

Anime & Manga

• Code Geass:
  • Lelouch's ideals were to fight against injustice and tyranny caused largely by the Britannian Empire. Later, he causes changes in the empire itself, and in the end helps make the world a better place for almost everyone, at the cost of his life and reputation, while passing on the torch of Zero to Suzaku.
  • Earlier in the second season, Lelouch pulls off a Moment of Awesome by exploiting this trope. When cutting a deal with the Britannians, they want to know if he's the original and he gets them to agree that it doesn't matter, because anyone who wears the costume and espouses the beliefs is "Zero". Then when the Britannians announce that they're formally exiling Zero from Japan, a million of his supporters put on Zero costumes, meaning the Britannians are forced to exile all of them, giving him a million-strong army (the only reason why that same million isn't just exterminated on the spot on the off chance that the real Zero is among them and to give all other rebels a lesson and they were seriously entertaining the idea) is because the one in charge (Suzaku) still held a degree of Honor Before Reason and had given his word that this agreement would be upheld no matter what).
• In Demon Slayer: Kimetsu no Yaiba, this is part of Big Good Kagaya's Kirk Summation to the Big Bad Muzan, that so long as people have the will to fight demons, they'll never stop, and eventually he will die. As Muzan sees those words come to fruition with the entire Demon Slayer Corps risking everything to kill him and succeed, Muzan adopts this philosophy and turns The Hero Tanjiro into his last and greatest demon, one who will carry on his will and destroy the Corps for him. Unfortunately for Muzan, Tanjiro mentally and physically (via an antidote) rejecting his demonhood means that Muzan's will ultimately dies with him.
• In Dr. STONE, Tsukasa kills Senku after the latter refuses to give up science when they awaken after having turned to stone for the past 3700 years. Tsukasa fears that Senku's plans to use science to revive adults and bring back the corruption they inherently had would ruin the new stone world they found themselves in. However, Senku manages to survive the assassination attempt, and is amazed at a man named Chrome who had collected various items throughout his life, being fascinated by things and doing primitive experiments on them. Senku realizes that even had Tsukasa killed him, he couldn't have been able to stop everyone who like Chrome, was innately curious about how the world worked. And sooner or later, humanity would rediscover much of the science and technology that had been lost from the old world.
• In F-Zero: GP Legend, before his base is destroyed, Black Shadow yells that he'll never die, nor will his dreams. Captain Falcon responds by Falcon Punching him.
• Future Robot Daltanious:
  • After the Big Bad reveals his true motive for destroying the Helios Empire (centuries of abuse and discrimination towards clones like himself), he says this.
    Dolmen: Kento Tate, even if I am dead, don't think for a second that this is over!
    Kento: W-What?
    Dolmen: As long as planets have a need for clones, or if clones like us exist on a planet somewhere...our hatred and sadness will never disappear!! There will come a time when the flames of rebellion will flare up again!
  • To specifically avert this, Harlin establishes the Galactic Federation Republic, a new nation where everyone is equal, clone or not.
• One Piece:
  • Both Gold Roger and Dr. Hiruluk died embracing this ideal. Gold Roger manages to start the Golden Age of Piracy.
  • In the face of a Marine victory which could have snuffed out the Golden Age of Piracy, Whitebeard, with his last breath, proclaims that Roger's treasure does exist, thus reigniting the idea once more. The Marines were not happy with this.
  • The villains of the Fishman Island arc attempt to invoke this, hoping to have their grudge against humans carry to the next generation by killing as many people as they can (humans and Fishman alike) when it looks like they're not going to win. As it turns out, you can kill an idea, if you do it with a contrary one. Luffy's human (though we use that loosely) crew fighting to protect Fishman Island causes that idea to blow up in their faces.
  • Upon once again facing the products of its existence, Jaygarcia Saturn of the Five Elders expresses rage and disdain toward the fact that despite centuries of trying, he still cannot scrub Sun God Nika and the religion that worships him from the world.
• Ōoku: The Inner Chambers:
  • After Ieharu's death, her councilors banned the study of Western Medicine and executed Gosaku for teaching it in an attempt to suppress any attempt to cure or prevent the Redface Pox and restore the gender imbalance. However, because he pleaded for his students to be spared, they were merely banished from the Ooku, which enabled them to secretly continue their attempts to end the Redface Pox.
  • At the very end, thanks to the combined efforts of Chikako and Tensho-in, the Imperial envoy Saigo Takamori elects to use the fact that the Tokugawa matriarchy assumed male names (and of course, the fact that Chikako as 'Prince' Kazu' was female) to stage a coverup and say the Tokugawa shogunate had always been a patriarchy. To that effect, he and his forces burned any evidence to the contrary, including the fine clothes of the Ooku and the Chronicle of a Dying Day. However, the final chapter shows a now commoner Tensho-in telling a young girl named O-Ume about how the shoguns were women. (There's a certain irony to this, that failing to kill the idea of ending the Redface Pox eventually led to them attempting to kill the idea of a Tokugawa matriarchy.)
• After the formation of the team Dai Gurren in Tengen Toppa Gurren Lagann, Kamina dies in the middle of the battle against every prediction. During the rest of the series, he is remembered constantly as a role model for the main cast (especially Simon), to the point that the new futuristic city is called Kamina City.

Comic Books

• In 300, Xerxes angrily declares that once he defeats the Spartans, he will completely destroy them and wipe out any trace of them from history.
  Leonidas: The world will know that free men stood against a tyrant, that few stood against many and, before this battle is over, that even a god-king can bleed.
• Batman:
  • Bruce Wayne isn't the only one who's taken on the role of Batman. Many incarnations of the character support the theme of Batman being more of an idea than a single person (especially The Dark Knight Trilogy).
  • In one of the tie-ins to Dark Nights: Death Metal (an event revolving around evil alternate versions of Batman), the Owlman, Batman's original evil duplicate from another universe, learns that he has died again and again in several alternate universes, which prompts his Heel–Face Turn. As he pulls of a Heroic Sacrifice to kill the evil batmen, he gloats that they will all be forgotten with time. He, on the other, is immortal. No matter what the universe might be rebooted into, there will always be an Owlman because he's just that good an idea.
• This is kind of what Deadpool attempts in Deadpool Killustrated; having discovered that killing the Marvel Universe doesn't actually achieve anything, he's now going through classic literature killing the archetypes that the Marvel heroes are based on, in the hope of killing the idea of the Marvel Universe.
• This is more or less the Central Theme of Grendel. In life, Hunter Rose is nothing more than a somewhat above-average criminal wearing a mask. In death, events converge to gradually transform his supervillain persona into the founding principle and guiding philosophy of a mighty imperial dynasty that comes to dominate the entire world. After a point, "Grendel" stops being a person and starts being an eternal, indestructible ideal.
• In the Judge Dredd story "Shrine", Dredd finds a memorial at a site where some juves (teenagers) were killed by the Judges, and incinerates it. It returns the following night, and he incinerates it again. Eventually he stakes the location out, and ends up killing the juves responsible when one pulls an obviously fake weapon. The next night, he finds two memorials. The last panel shows them both on fire, but some juves already preparing to restore them.
• In The Sandman (1989), it is established that the Seven Endless are capable of being killed (the methods and logistics being as archaic and eldritch as the Endless themselves) but should the current incarnation of the Endless be killed, they will be replaced with a new one because the Endless are the Anthropomorphic Personifications of abstract concepts that permeate the universe. This first happened with Despair and later with Dream, Morpheus having his place taken by Daniel as the new incarnation of Dream. It is even implied that this will happen with every Endless (with the exception of Death, of course) before the universe ends.
• The Transformers (IDW): In the first issue of the Ironhide miniseries, this is why Optimus believed the war would be going on for a while in its early days, as both sides were fighting for a philosophy. He admits that while ideas can't be defeated, they can be changed and resolved to keep fighting until someone could figure out how to do so.
• V for Vendetta: The anarchist title character, to Eric Finch, who's just shot him:
  V: Did you think to kill me? There's no flesh or blood within this cloak to kill. There's only an idea. Ideas are bulletproof.
• Watchmen: Rorschach's journal is heavily implied to have been published after the events of the graphic novel, revealing Ozymandias' master plan to the wide public, even though Dr. Manhattan killed Rorschach specifically so that it doesn't happen. Two wholly separate Alternate Universe continuations — Doomsday Clock and Watchmen (2019) — then go on to show that the way the idea survives is probably not the one Rorschach would have been pleased to be part of.
  Rorschach: Never compromise. Even in the face of Apocalypse, never compromise. [seconds after that, Dr. Manhattan blows him up]

Comic Strips

• The Phantom: Go ahead, try to kill him. You might succeed, it won't help.

Fan Works

• An evil example in Kill Them All. Samael boasts that it cannot be killed as the mere idea of its existence will ensure it can manifest again by feeding on humanity's primal fears. Taylor then subverts this by pointing out you can kill an idea if you're willing to kill everyone who shares the idea or, as she later does, make everyone realize the idea itself is wrong.
• Another evil example in the prologue to Shadowchasers: Conspiracy; in a flashback set in 1945 during the siege of Berlin, an American Chaser named Anderson Steading and two others have cornered a Nazi officer who is, in reality, an illithid.
  Steading: I'm not warning you again. As of this moment, I'm no more impressed by the title of 'Fuhrer' than I am of the powerless weakling an illithid is when it can't use its psychic powers. Now put your slimy hands up or I swear I'll send you to Hell to meet him.
  Illithid: I don't care... No matter how many of us you pigs kill... [draws a knife] ...you can't kill an idea!
  [Illithid lunges, but Steading and his men open fire, killing him]
  Steading: Maybe... But an idea can kill you...

Films — Live-Action

• In And Quiet Flows the Don, Podtyolkou the Bolshevik says this right before his execution, telling the crowd that they'll be sorry later and that all Russia will be Bolshevik.
• Ben-Hur (1959): Messala takes command of the Jerusalem Garrison and has this exchange with the former commander Sextus: "Yes, Messala, but how do you control what's up here? [Sextus points to his head] How do you fight an idea? Especially a new idea." Later, Messala responds: "Sextus, you asked how to fight an idea. Well, I'll tell you how... With another idea."
• Braveheart: William Wallace, right after being racked, stretched by horses, and disemboweled, defiantly yells "FREEEEDOOOOOOMMM!"
• In Casablanca, Victor Lazslo tries to assert this about La Résistance against the Nazis. The film itself does a good job of illustrating the concept. Unfortunately, Those Wacky Nazis also have ideas and ones that Lazlo is kinda, you know, trying to kill.
• The Dark Knight Trilogy:
  • Bruce Wayne uses this sort of reasoning when devising his future role in Batman Begins, as advised by Henri Ducard. A man acting just by himself as a man can be killed, bribed, or discouraged, but by becoming a 'symbol', the man becomes "more than just a man"; even if he dies, the symbol lives on to inspire others. Guess what symbol Bruce eventually settles on... It's heavily implied that Ra's Al Ghul has operated by the same principle.
  • It plays out again in The Dark Knight Rises. Bruce Wayne fakes Batman's death and retires from superhero-ing, but he leaves the keys to the Bat Cave with detective John "Robin" Blake, so Blake can be the hero that Gotham needs.
• Dead Poets Society: While Mr. Keating gets fired over supposedly causing Neil's death, he leaves knowing that the teachings he imparted will stay with his students, as the formerly timid Todd stands up on his desk to salute Keating, prompting his fellow society members (and even some other students) to also take a stand in defiance of Dean Nolan's demands that they stay seated. As the students stand, Nolan's voice gets drowned out in the swelling score, which leads Keating to say "Thank you, boys. Thank you." as he leaves.
• Played with in Dogma; Rufus comments that he sees "ideas" as malleable and they can change or be adjusted to fit new evidence and circumstances. (And yes, they can even die out). "Beliefs", on the other hand, are ideas that have become fixed in place, and are much harder to even slightly change, let alone kill. The fact that a belief is hard to kill is not necessarily a good thing if the belief in question is not a good one, or if the belief has become an overly rigid and unthinking dogma.
• Equilibrium: "A heavy cost. I pay it gladly." Partridge refuses to give in to Preston, deconstructing the meaning of a system without emotion. Being aware that he has just committed a sense offence, he faces death in the most composed way possible as a form of his defiance, because he'd rather die for his beliefs than be committed to a corrupted establishment. Fair to say, his words continue to reverberate as Preston unravels the truth and the Resistance gain a chance to seep through.
• The Hunger Games: Mockingjay has Katniss telling President Snow that the rebellion will never submit to him, regardless of his atrocities. There are also scenes in which this promise of Katniss gets validated by many impressive Heroic Sacrifices.
  Katniss: You can torture us. You can bomb us. You can burn our districts to the ground. But do you see that? Fire is catching! If we burn, you burn with us!
• Inception addresses this and emphasizes why it is so hard to plant one. The title refers to the act of doing so, but the main obstacle is that the subject has to believe it's their own idea for it to stick. The next complication is that the idea will grow to define their entire life... even to suicidal extremes.
• Iron Man Films:
  • Iron Man uses a villainous version. It's one thing if you want your idea to spread and inspire people, but what if you want to keep your idea — like, say, the key to Powered Armor — to yourself to avoid it being abused?
    Stane: You think that just because you have an idea, it belongs to you?
  • Iron Man 2 confirms this. Iron Man's existence made the whole world realize that Powered Armor is a viable and powerful weapon. Tony initially downplays the problem because he's one of the only people who can actually make a reliable suit. Unfortunately, the villain of the movie is also smart enough to make his own suit, and he's got a grudge against Tony.
  • Vanko believes he has killed an idea, having attacked (and nearly killed) Tony. The idea, specifically, being that Iron Man can't be beaten. "If you could make God bleed, people would cease to believe in Him. There will be blood in the water, the sharks will come. All I have to do is sit back and watch as the world consumes you." He's kind of right, and much of Tony's Character Arc in the later Marvel Cinematic Universe films demonstrate his increasing inability to keep things from spinning out of control despite his best intentions.
• Lady from Chungking: Kwan-Mei is the leader of a Chinese La Résistance group, fighting against the occupying Japanese. At the climax of the film her people blow up a bridge, derailing a major Japanese offensive, but Kwan-Mei is caught in the process. As she stands in front of a firing squad, she's defiant.
  Kwan-Mei: You cannot kill me! You cannot kill China!....When I die, a million will take my place, and nothing will stop them!
• In The Last Jedi, an embittered Luke sets out to destroy the sacred founding texts of the Jedi and finally put the failed order out of its misery. As he approaches the tree-shrine they're stored in, Yoda's ghost appears, and Luke expects his old teacher to try to talk him out of it... only for Yoda to casually destroy the texts himself. He then laughingly tells Luke that the Jedi creed had long outgrown a few boring old scrolls on philosophy, and in any case copies of them were common.
• The Matrix features this trope quite heavily. The idea that the human mind cannot truly function without a real choice plays into the design of the Matrix itself and the cycle of the One as a means for the machines to keep the human population under control. The entire trilogy revolves around breaking this control for true freedom.
• In Star Trek VI: The Undiscovered Country, Chancellor Gorkon is assassinated for advocating for peace between the Klingon Empire and the Federation. But his daughter, who becomes chancellor, continues his efforts, and Gorkon's sacrifice challenges Captain Kirk's prejudice against Klingons.
  Gorkon: Don't let it end this way, Captain.
• V for Vendetta had an epic one near the end. After taking dozens of bullets and killing a dozen men before they could finish reloading (as per his Badass Boast), V approaches The Dragon-in-Chief, who asks, in disbelief, "Why Won't You Die?!" His response? "Beneath this mask is more than flesh; beneath this mask, there is an idea, Mister Creedy — and ideas. Are. Bulletproof." The literal Bulletproof Vest helps, if only for a while; he dies shortly thereafter to his wounds.
• The Bad Future in X-Men: Days of Future Past is set off by Mystique killing Trask, since he was the head of the Sentinel program. Killing him only convinced others to continue his work and the future happened. When it comes down to it, the Aesop is that you cannot kill an idea, but you can discredit it. The inverse occurs when she spares him and saves the President. Trask instead gets arrested for trying to sell military secrets to the North Vietnamese government at the Paris Peace Accord, causing the program to be shelved.

Literature

• Nineteen Eighty-Four: Winston and Julia discuss this trope, coming to the agreement that though the Thought Police can force you to say whatever they want you to say, they cannot force you actually mean it. It's later horrifyingly Double Subverted: The Thought Police can kill any idea that does not confirm to the Party's totalitarian worldview. They will make you mean whatever they force you to say, and nothing will ever be the same afterward... but they will still keep the possibility of the ideas and the opportunity for dissent alive in order to justify the Party's existence and to tempt dissidents to come out of hiding.
• Belisarius Series: Used seriously at first, and then humorously. Belisarius starts a rumor about sexual prowess and general horniness of the Kushans in order to get Kungas and his men pulled away from their guard duty of a captured princess. Their incompetent replacements are easily dispatched and allow her to be rescued. Later, once the confused Kushans find out about the origin of the rumor, they then take delight in spreading it themselves.
• Played for Laughs in Discworld on several occasions, frequently with people using rumors that once they get started cannot be stopped. In Interesting Times, for instance, Rincewind goes around telling soldiers that in no way are there any invisible vampire ghosts about to attack them in the following battle and there are absolutely not 2,300,009 of them.
  • Of course, Discworld takes it literally many times. Witches Abroad introduces the idea that on the Discworld, stories have not only memetic influence but are a law of nature. In Soul Music and Moving Pictures, the immortal idea (rock music and movies, respectively) is the Big Bad.
  • In Thief of Time, the Glass Clock (which destroyed all of history in the past) was removed from any books by the History Monks, but something that strong still seeped through and found its way into children's stories.
• Subverted in The Dresden Files. The Oblivion War is an ancient ongoing war against old malevolent gods and demons who now are remembered only by a scant few mortals. If those mortals die and all records of the god are destroyed, and no one is there to take up remembering the name, then the leader of the humanity's faction can fully delete the god and information about the god from the last possible source on Earth. This then banishes the god to oblivion. One advantage for the gods' factions is even accidental knowledge of the god is enough to make a binding. So, if one put the name of a god on Twitter and tweeted it to 10 people, they would become binds to the mortal realm. They would need to die before the human's leader could act. Thankfully, Humanity's leader is patient enough to wait a thousand years to really make sure all records and knowledge are destroyed, so waiting a hundred years for these mortals to die is okay as long as they don't start spreading the name further and become liabilities or agents of the god. One saving grace of the limits to knowing this is the gods must be known by a mortal being. If a spirit of knowledge learns of the War or a god's name, it won't become a tie to the world. The novella Backup goes into a bit of detail about The Oblivion War where a side character who participates behind the main hero Harry Dresden's back. We don't get a lot of information, but since the antagonist is a cultist of said gods, and Thomas (the novella protagonist) mentioned the war has been ongoing for thousands of years, it fits. It is said in the novella, Humanity's side cannot even know how many victories and banishes they have made because even that could risk some of the defeated enemies a chance to come back.^note As an interesting side note, there is zero mention of the Oblivion War in any of the main series novels, even though, according to Word of God, Thomas has been actively participating in it since the beginning of the series (and before), specifically because Thomas does not want to and cannot let Harry know anything about it: since the main series is told in First Person, the reader only knows what Harry knows. There are very subtle hints in the stories, but they have no connecting thread without the context of Backup.
• In the Eighth Doctor Adventures, a group of Time Lords (the Celestis) take this concept literally, and convert themselves into ideas for this very reason. Unfortunately for them, a later book reveals that the Whoniverse also contains creatures which can kill — and eat — ideas.
• In It Can't Happen Here, the totalitarian government never completely stamps out people's longing for freedom and dignity. Revolts erupt across America as people take back areas from Haik's forces. Doremus, in particular, exemplifies this trope, continuing the struggle after having lost loved ones, endured torture and incarceration, and lived in lonely exile.
  And still Doremus goes on in the red sunrise, for a Doremus Jessup can never die.
• This is the crux of Kelsier's Thanatos Gambit in Mistborn. He purports himself as a figure of legend and a symbol of evolution so that when he is killed, a vengeful religion rises up immediately to complete his work in his name.
• In "Souvenir", by Philip K. Dick, everyone on Williamson's World is killed, but one of the people involved brings some trinkets from it home and gives them to his son, and the story ends with the son looking at them with "a strange light in his eyes".
• The Star Wars Expanded Universe will never be rid of the Mandalorians. Why? Well, in the words of Mandalore the destroyer:
  "Here's why you can't exterminate us, aruetii.^note 'Aruetii' refers to someone not Mandalorian, or traitors. We're not huddled in one place — we span the galaxy. We need no lords or leaders — so you can't destroy our command. We can live without technology — so we can fight with our bare hands. We have no species or bloodline — so we can rebuild our ranks with others who want to join us. We're more than just a people or an army, aruetii. We're a culture. We're an idea. And you can't kill ideas — but we can certainly kill you."
• The Stormlight Archive:
  • Spren are living ideas. The more common ones are things like wind and rot and anger, but more powerful and intelligent ones are spirits of honor and lies and law. Normally, killing any of these is essentially impossible, but there is one way to kill them on an individual level: When they bond with a human (which grants that person special powers), the spren gains the ability to maintain their sentience in the Physical Realm, but they also become vulnerable. If the human does not hold to their oaths (the precise oath varies depending on the spren), the spren will weaken and eventually lose their sentience. Actively breaking their oaths will actually kill the spren. They can be brought back if the human re-swears their oaths.
  • The spren who were bonded to the old Knights Radiant were all killed during the Recreance when all the knights broke their oaths at once. Since the spen were also their Shardblades, they were locked in that form when they died, and the kingdoms of the world have been using the corpses of spren as the most dangerous and valuable objects for millennia. A non-Radiant can bond with a Blade, giving the spren a simulacrum of life for a moment (enough to be summoned and dismissed at will), but no more. Truly bringing them back to life has been implied to be possible but very difficult, as their original bonded knights are long dead. According to Word of God, it would not only require a wielder of the dead blade to swear the oaths of the order of the Knights Radiant the spren was associated with but something more to forge a new bond with the spren and heal their mostly destroyed minds..

Live-Action TV

• In Babylon 5, at the climax of the Vorlon-Shadow War, Delenn and Sheridan point out that, even if they and their coalition are killed, their assertion that the younger races no longer need the First Ones is true. All the First Ones can do is subjugate them, not "teach" them as the two sides insist they want to.
• In the Blake's 7 episode "Project Avalon", Travis has captured the titular Avalon, who has started numerous resistance movements against the Federation. Avalon defiantly tells him that the Federation cannot actually stop people from forming groups to oppose them. Travis somewhat agrees with her but then states they will persevere regardless.
• In The Daily Show, Mo Rocca suggests that to adequately fight the War on Terror, what America needs is "a bomb that destroys ideas".
• Doctor Who:
  • "The Christmas Invasion": The Doctor is able to destroy a prime minister with this trope. He only needs to say six words to an aide: "Don't you think she looks tired?" She doesn't die (quite the opposite, really), and the PM isn't necessarily evil, but he does use the principle of an idea being unkillable. He certainly comes to regret this.
  • "The Satan Pit": The Doctor references the trope when he confronts the Beast's body and realizes that it's an Empty Shell, with the Beast attempting to escape by sending its mind away inside someone. While the mind may not be as powerful as it would be inside its own body, it could still spread the evil throughout the universe, knowing how hard it is to defeat an idea.
  • "Rosa": The antagonist, a Politically Incorrect Villain from the far future, is trying to kill an idea by derailing the American Civil Rights Movement. He can't literally kill anyone due to a Restraining Bolt, so he has to resort to other methods, while the Doctor and company work to stop him.
• Discussed in a Nova episode on radicalization, "15 Years of Terror". One of the interviewees points out that the only thing that kills a bad idea is a better idea.
• This is how Gotham treats Jerome and Jeremiah Valeska. Since the showrunners were forbidden to use the name "The Joker" by Warner Bros., the show sets up the idea that Jerome comes up with the archaic style, the smile and other Joker-identifiers, but when he dies, Jeremiah unwillingly takes up the mantle, making sure Jerome's ideas of wreaking havoc is continued in Gotham while the former is dead.
• The Outer Limits (1995): In the episode "Final Exam", this trope is discussed in relation to the moral and environmental implications behind cold fusion bombs and the advance of technology overall. When Martin questions how Todtman reached his breakthrough with cold fusion technology before the Here We Go Again! ending in a different university implies that the same scenario will take place:
  Todtman: So simple once they ask the right question, only they're expecting the wrong answer.
• Sherlock:
  • In the episode "The Reichenbach Fall", Donovan and Anderson manage to sow the seeds of doubt regarding Sherlock's authenticity as a (relatively) aboveboard detective. When Lestrade comes to warn Sherlock of his impending arrest:
    Sherlock: After all, you can't kill an idea, can you? Not once it's made a home... [taps Lestrade's forehead] There.
    • This is the whole point of the episode, with Moriarty managing to convince everybody that Sherlock is a fraud and that even "Moriarty" is a paid actor hired by Sherlock. He proves it by killing himself, forcing Sherlock to jump from a rooftop lest all his friends die.
  • This is then reversed in the "The Empty Hearse", which shows that given enough time, cooler heads were able to re-examine the subject and found major faults in the original theory. Once discredited, the idea quickly dies off and when Sherlock is revealed to be still alive, the public embraces him once again as a hero.
• Star Trek: Deep Space Nine: In "Far Beyond the Stars", Benjamin Sisko, dreaming that he's a science fiction writer in the 1950s, reacts rather badly to having his story pulped because it has a black Captain.
  Sisko: You can deny me all you want but you can't deny Ben Sisko — he exists! That future, that space station, all those people — they exist in here! In my mind. I created it. And every one of you knew it, you read it. It's here. Do you hear what I'm telling you? You can pulp a story, but you cannot destroy an idea, don't you understand, that's ancient knowledge, you cannot destroy an idea. That future — I created it, and it's real! Don't you understand? It is real. I created it. And it's real! It's real!
• Star Trek: The Next Generation:
  • In "Angel One", crewmen from a Federation freighter have been stranded on a planet ruled by a matriarchy. The Enterprise crew finds them, inadvertently revealing their hiding place to the local regime. The local leader originally intends to execute them, but Riker invokes this trope to convince her to reduce the sentence to exile in a distant region of the planet. She admits that she cannot kill the idea of gender equality, but handling the incident in a low-key manner will keep it from spreading too fast.
  • In "Birthright", Worf discovers a Romulan prison camp where Klingons and Romulans have learned to live together in peace. However, he finds that the Klingon children are not informed about their heritage. The Romulan leader, Tokath, finds him a threat to this peace and demands that Worf stop or else he'll get executed. Worf tells him he is content to Face Death with Dignity for this reason.
    Worf: I am being executed because I brought something dangerous to your young people. Knowledge. Knowledge of their origins. Knowledge of the real reasons you are here in this camp. The truth is a threat to you.
  • In "Rightful Heir", Chancellor Gowron talks about the symbolic effect of the return of the Klingon God-Emperor:
    Gowron: Kahless has been dead for a thousand years, but the idea of Kahless is still alive. Have you ever fought an idea, Picard? It has no weapon to destroy, no body to kill.
    • Later in the episode, the same argument is used to convince Gowron to let Kahless be a figurehead Emperor rather than oppose him. When a counter that this Kahless is a clone is made, Worf points out that it won't matter to a good number of Klingons, who will still see him as a reincarnation of the original's spirit/ideals and would only result in fracturing the Empire if opposed. Gowron is forced to, reluctantly, kneel before Kahless (even though Gowron is still in charge).
• The Twilight Zone (1959):
  • "He's Alive" has it work for both good and bad. After Peter betrays his former friend Ernst and shoots him, Ernst warns him that the ideas he fought for — equality, freedom and justice — will not die by a single bullet. At the end, when Peter dies, his Spirit Advisor Adolf Hitler returns to the shadows to find another to guide. Rod Serling then warns the audience that the ideas that Hitler fought for — oppression, hatred and prejudice — are also ideas that will exist so long as people continue to allow them to.
  • "The Obsolete Man" deals with a man named Romney Wordsworth. He lives in a dystopian future where everything must have a purpose and able to fulfill that purpose or else the State shall declare the person obsolete and remove the person. If the person's purpose is similarly declared obsolete, then that too will carry the same punishment. Among the many things which the State declared obsolete is religion. Not just Christianity, though that is Romney's faith as well. Even stating this during his trial on whether he is obsolete or not earns a fiery declaration from the Chancellor that there is no God because the State has proved that there is no God. In reference to this trope, Romney declares, "You cannot erase God with an edict." In a similar vein, after he is declared obsolete and sentenced to die, Romney crafts a plan to implant more than a few dangerous ideas into the audience his execution will be broadcasted to. Romney has a bomb set up in his apartment and invites the Chancellor to his place, with the latter being ignorant to how Romney will die. Once inside, Romney locks the door and poses a challenge of faiths to the Chancellor; his in the unbending power of the State and Romney's in God. For the next half hour, as the time of the explosion draws near, Romney reads aloud from his Bible passages not just for his own strength but passages that those watching can find strength in to further resist. The Chancellor, knowing that his people won't openly save him as it would be a sign of weakness, breaks on television and screams in the name of God to be let out. In God's name, Romney unlocks the door but remains inside as the explosion kills him. The next day, for his disgraceful actions the Chancellor is now declared Obsolete and taken away by a horde to be killed.

Mythology and Religion

• Norse Mythology: Rather epically summarized by Odin during Ragnarök:
  Old Norse: Deyr fé, deja frændr, deyr sjalfr it sama, en orðstírr deyr aldregi, hveim er sér góðan getr.
  Norwegian: Fe dør, frende dør, en sjøl dør på samme vis; men ordets glans skal aldri dø i ærefullt ettermæle.
  English: Cattle die, kinsmen die, we ourselves also die; but the fair fame never dies of him who has earned it.

Music

• Peter Gabriel invokes this trope in the song "Biko", a tribute to South African martyr Steven Biko, with following lyric:
  You can blow out a candle, but you can't blow out a fire
  Once the flames begin to catch, the wind will blow it higher
• The point of the song "I Dreamed I Saw Joe Hill Last Night", as recorded by Paul Robeson, Joan Baez, and others.
• The German folk song "Die Gedanken sind frei" ("Thoughts are free") is all about this. Sophie Scholl, a member of the White Rose, famously played the song on her flute outside the walls of Ulm prison in 1942, where her father Robert had been detained for calling Adolf Hitler "a scourge of God".
• The Aviators song "Bulletproof" is all about this:
  You can shoot me down, but you're never gonna hide the truth
  'Cause words are bulletproof
• The Abolitionist song "John Brown's Body" has this as it's central theme. John Brown was fed up with the movement's attempts to peacefully end slavery in the U.S. and tried to start a slave rebellion in Virginia, which ended in his arrest and eventual hanging for treason (the first person convicted of the crime in the U.S.). John Brown's raid of the federal armory in Harper's Ferry, Virginia (today West Virginia) occurred less than two years before the start of the American Civil War. In fact, the "Battle Hymn of the Republic" was set to the tune of this song.
  Old John Brown's body lies moldering in the grave
  While weep the sons of bondage whom he ventured all to save
  But tho he lost his life while struggling for the slave
  His soul is marching on

Tabletop Games

• Don't Rest Your Head: One of the Madness talents in Don't Lose Your Mind grants you a knife that can cut, sever or kill anything, including ideas. There's always a ritual quality to such an act — dubbed memeticide — for instance, slitting Fidel Castro's throat would kill the idea of Communism in Cuba, meaning the idea not only gets forgotten but loses all momentum and will never be taken seriously anymore. That being said, the knife can also cut off flaws, sever abusive relationships, and kill personal demons.
• Inverted in Mage: The Ascension. This from the Revised Void Engineer splatbook: One Deviant told me that I could take his life, but I could never kill his dreams. This was incorrect. The standard protocol for killing an RD's dreams requires two sniper/spotter teams with Primium hypervelocity weapon loads, and an officer operating a hyperdimensional field generator. Let's practice now.
• Inverted in Mage: The Awakening as well — you quite literally can go into the collective Dream Land of humanity's subconscious, find the embodiment of an idea, and kill it. The most powerful archmages can snuff out a concept from every mind on Earth in this way.

Theatre

• Alluded to by Grantaire in Les Misérables (before the show was cut down), after "Little People": "Though we may not all survive here, there are things that never die!" Also alluded to in the final battle, when Enjolras remarks that even after their defeat, others will take their place "until the Earth is free!"
• The New Moon: In the Finale Act I, after the masks come off and Robert is captured:
  Ribaud: So, Monsieur Beaunoir, the sooner your ship can set sail, the sooner we can treat Paris to a most amusing execution.
  Robert: [as men sing "Stouthearted Men" offstage] All right, Ribaud, you have won, but long after my amusing execution something will live after me. Listen! You hear that — that song, that spirit will destroy you and your king, and all the cruelty you stand for!

Video Games

• Assassin's Creed:
  • In Assassin's Creed, Altaïr found out the hard way that the Knights Templar are not just Crusaders. They can also be Saracens and even Assassins as well, like his mentor, Al Mualim. As long as there are people who believe the world must be controlled in order for there to be peace, the Templar Order will never be rid of.
  • In Assassin's Creed II, one of the Codex pages reveals that Altaïr mused on this subject more than once, noting that the Templars waged war by seeking to win over the hearts and minds of people with ideas, rather than more conventional weapons. This made it rather difficult for the Assassins to fight back... But it also makes it rather difficult for the Templars to exterminate them.
    Altaïr Ibn-La'Ahad: ...how does one wage war against a concept? It is the perfect weapon. It lacks a physical form yet can alter the world around us in numerous, often violent ways. You cannot kill a creed. Even if you kill all of its adherents, destroy all of its writings – these are a reprieve at best. Someone, someday, will rediscover it. Reinvent it. I believe that even we, the Assassins, have simply re-discovered an Order that predates the Old Man himself...
  • Exaggerated in Assassin's Creed III by Haytham Kenway when fighting Connor; while the Assassins are literally born of lifetimes of discipline and self-study, the Templars grow like weeds no matter what the Assassins do because Evil Is Easy and Evil Pays Better. The Templars are even more resilient than the Assassins because they're not even an idea — they're the absence of one.
    Haytham: Even when your kind appears to triumph, still, we rise again. And do you know why? It is because the Order is born of a realization. We require no creed! No indoctrination by desperate old men. All we need is that the world be as it is. And this is why the Templars will never be destroyed!
  • Said word-for-word in Assassin's Creed: Odyssey: Legacy of the First Blade by Amorges about the Order of the Ancients, the precursors of the Knights Templar:
    Amorges: The Order aren't just a group of people — they're an idea. An idea cannot be beaten. An idea cannot be destroyed.
• Invoked in Deus Ex when the terrorist leader says that 'You can't fight ideas with bullets', a running theme throughout the game.
  The Doctrine of the Mighty: A single artist, a single general, a single hero or a single villain may all die, but it is impossible to kill a people, a nation, an idea — except when that idea has grown weak and is overpowered by one that is stronger.
• Invoked in The Elder Scrolls V: Skyrim by Ulfric Stormcloak. Partially subverted if you complete the Imperial Legion questline — while there would still be holdouts, most will eventually lay down their arms and return to their homes.
• Knights of the Old Republic II: The Sith Lords: This is one of Kreia's favorite tropes. She points out that killing men is easier than killing belief and that Revan, in the process of fighting the Mandalorians, adopted Mandalorian tactics and their intolerance for the "weak". She also points out that every time the Jedi and Sith fight each other to near-extinction, the ideals of either side still remain as strong as ever, waiting for their chance to strike back in revenge and dooming the galaxy to endless warfare. Subverted with Kreia herself — not being the most social woman, her worldview ultimately died with her, since the only person she bothered teaching it to didn't share it (plus she had a nasty habit of killing those to whom she preached). No other character in the Star Wars universe ever expresses the same view on the Force ever again.
• In MadWorld, XIII says that he wants to see an idea die. A culture, a religion — any idea. He got his wish. The Blood Sport Deathwatch is dead.
• In Mass Effect 3, the Illusive Man cites this trope as the reason Cerberus will never fall, even with their headquarters in ruins and their forces scattered.
• In Metal Gear Solid 2: Sons of Liberty, the Patriots invoke this trope to justify why they will always exist. They (through their A.I. programmed to talk to Raiden) explain to Raiden that they are the very moral and intellectual consciousness of the United States of America, every idea that comes into the collective consciousness of each American citizen originates from them. You can't kill the Patriots as an organization because they aren't simply a business that can be shut down but an idea in and of itself.
• Victoria: An Empire Under The Sun and its sequel, spanning from the early 19th century (specifically, 1836) to right before World War II, has this in the gameplay — your population will get silly ideas such as minimum wages and universal suffrage on their minds. Starting revolts if the pressure of having enough people saying they want it isn't enough. Victoria 2 adds a suppression mechanic to stop ideas you find dangerous. However, it is a temporary reprieve — the suppressed movement will most likely show up again after a few years and be more radical and inclined to violence.
• Cruelly subverted by Sylvanas Windrunner in her Warbringers short in World of Warcraft. The Horde has just attacked Darkshore and is about to capture Teldrassil, the Night Elves' home. Conversing with Delaryn Summermoon, a Night Elf Sentinel who is dying from her wounds, Delaryn tells Sylvanas that she has made life itself her enemy, and that's a war she'll never win because she simply can't kill hope. Sylvanas coldly responds, "Can't I?", turns Delaryn's head towards Teldrassil, and orders her soldiers to burn it down.^note Sylvanas had also planned to kill Malfurion Stormrage to demoralize the Night Elves, and when High Overlord Saurfang strikes Malfurion from behind and renders him unconscious, Sylvanas leaves to oversee Teldrassil's capture, ordering Saurfang to bring her Malfurion's head. Saurfang, however, refuses to kill him since his back was turned when Saurfang attacked. This allows Tyrande Whisperwind to swoop in and rescue Malfurion, leading Sylvanas to discover that Malfurion is still alive and doing the next best thing.

Webcomics

• Remus Shepard has a go at this in Indefensible Positions, then deconstructs it in Genocide Man.
  • In the former, ideas are actually living creatures known as demons but are dependent on belief from humans to survive.
  • However, the protagonist of the latter argues that an idea can be killed and that some ideas should be killed — even if the only way to do so is to slaughter every single person who holds the idea.
    Jacob: Your threat comes from what you represent — the idea that human beings can be improved or replaced. Ideas like that are too dangerous to let live. The open source movement gave every idea an army of researchers. They turned military secrets into public knowledge, and children's science kits into biowarfare labs. That's how the Jews became extinct, why China is full of zombies, and why red hair became a death sentence. Two-thirds of the world's population died because of bigotry, insanity, or ancestral hatred. Because of ideas. There's only one way to kill an idea. You have to kill every person who holds it. Genocide is the answer, the antithesis of every idea. Today's ideas are dangerous enough to threaten the entire human race. That's why genocide is now law enforcement's number one tool. [emphasis added]
• Unsounded: Inverted by the authoritarian state of Alderode. The ultimate punishment, reserved for the most dangerous enemies of the state, is a murderous Hate Plague that poisons every Aldish citizen's mind against the memory of the condemned. Roger Foi-Hellick's rebellion fell apart as soon as he was cursed because it had his name on it.

Western Animation

• Parodied in Futurama:
  Old Man Waterfall: You can crush me, but you can't crush my spirit! [a giant claw crushes him] Ow! My spirit!
• Star vs. the Forces of Evil: A villainous example comes from "Cleaved". After Mina Loveberry and her genocidal army are de-powered, most of the heroes let her leave out of pity, except for an anonymous archer who simply shoots her. The first shot fails to connect, and Mina convinces her (in her unique words) that it wouldn't matter if she succeeded.
  Mina: You can get rid of me. It's so easy. But the sweet thing is, I'll never really be gone, 'cause I've got good ideas. And the thing about good ideas is they tend to kinda hang around, like a baaad fart.

Real Life

• The whole basis for The Game.
• Che Guevara's last words, according to at least one biography:
  "I know you have come to kill. Kill me if you wish, coward, but know that you can only kill a man."
• There were several sects of early Christians that are only known about by official church writings condemning them. In some cases, we only have the names and there must have been others where even that hasn't survived. In other cases; we know about their ideas because of things like the Nicene Creed, preserved by the Orthodox and Catholic Churches for the last 1700 years, which was written at the First Council of Nicaea to specifically exclude certain ideas that had circulated within early Christainity.
• In a 2001 book of "Quotations for Public Speakers", the U.S. ex-senator Robert Toricelli almost certainly incorrectly claimed that Josef Stalin had said:
  "Ideas are more powerful than guns. We would not let our enemies have guns, why should we let them have ideas?"
• Government propaganda targeted at an enemy intentionally invokes this trope, especially during wartime.
• Opponents of The War on Terror and War on Drugs invoke this trope as one of their points.
• Generally, outside attempts to forcibly repress or destroy an idea are doomed to fail, but ideas can destroy themselves if they inspire widespread revulsion and their practitioners are doing horrible things.
• A legal punishment in ancient Rome was damnatio memoriae, which was an attempt to erase a political figure completely from history after his or her death. Their faces would be removed from portraits, statues damaged, and anything mentioning their name would be destroyed or erased. This is extremely difficult to pull off completely — for instance, we have some surviving busts of Publius Septimius Geta, denarii featuring his image, and a wealth of information about his personality, tastes, family politics, and eventual assassination — and obviously, it's impossible to know if a complete damnatio memoriae ever occurred.
  • Possibly an ancient example of the Streisand Effect.
  • The Egyptian Pharaoh Thutmose III (or possibly his son Amenhotep II) tried to erase his predecessor Hatshepsut from history by destroying monuments and essentially painting over hieroglyph murals. The fact that it was his mother, who had led Egypt in a Golden Age (of admittedly strict rule), is just icing on the historical record cake. Oddly enough, he mostly succeeded, as the records that were destroyed have only recently been restored (partially) with advanced technology, and obviously missing some rather significant gaps. This was not done until significantly after Hatshepsut's death, and is believed to have been an attempt by her son and grandson to claim credit themselves for her accomplishments.
• A saying from the Norse Poetic Edda, attributed to Odin:
  Cattle die, kinsmen die, we ourselves also die, but the fair fame never dies of him who has earned it.
• A similar saying to this trope is utilized in the Occupy protests, by the slogan "You cannot evict an idea". Possibly a subversion, given that Occupy got stuck with the reputation of being a bunch of rich kids trying to convince the poor they were one and the same, a case of an idea eating itself. However, many of the ideas of the Occupy movement have been absorbed into the rise of the Democratic Socialist movement in the 2018 election cycle, which has also expanded on the concepts to apply the ideas to things beyond just banks.
• Tommy Douglas, former premier of Saskatchewan and founding leader of the New Democratic Party, ended his "Mouseland" parable as such:
  "But I want to remind you: that you can lock up a mouse or a man, but you can't lock up an idea."
• 2012 Presidential Candidate Ron Paul has stated this about his ideas:
  "Ideas spread, you can't stop them. An idea whose time has come cannot be stopped by any army or any government!"
• Black Panther Fred Hampton once said that "You can kill the revolutionary, but you can't kill the revolution." Subverted in a photo of policemen carrying his body out after the siege of Chicago with the byline "You can't kill a revolution but you sure as hell can kill a revolutionary".
• Plato was a pioneer of this trope. His philosophizing posited 'forms' existing independently of the real world — i.e., every chair may look different, but we recognize them as 'a chair' because they all reflect the form of the eternal chair. Hence, mankind will never forget how to make chairs because the idea exists separately from any one man. Things like 'justice', 'virtue', and 'goodness' were also forms. In his treatise The Republic, the leaders communed with 'the Form of the Good' and embodied it completely.
  • Two and a half millennia later, Carl Jung would adopt Plato's ideas for his theory of "archetypes", that every person is hardwired with mythological symbols that manifest in their myths and religions, while another Carl — Sagan — would savage Plato for the rise of religious dogma, by championing the supremacy of the mind over the science of the 'corrupt' natural world.
• This trope is one of the main reasons why many people (often science fiction writers) believe that going back in time to kill Adolf Hitler wouldn't prevent The Holocaust or World War II; once his sick ideas were planted in the minds of the Nazis, someone else (perhaps even crazier — or worse, more competent — than he was) would have continued his work if he was assassinated. Also, even if Hitler didn't come into power and lead the Nazi Party, racism, anti-Semitism, ableism, homophobia, etc. existed centuries before he was born, and live on to this day. It wouldn't be a stretch to assume that if Hitler didn't stir up the prejudices of the 1930s German public in order to get political support, someone else would have done so.
• Some individuals who oppose anti-hate speech laws and other policies aimed at directly suppressing hate groups argue that these measures may be ineffective in addressing the root causes of racism. They believe that simply throwing individuals in jail or silencing them publicly may not be enough to eliminate racist beliefs and attitudes. However, it's important to note that this is just one perspective, and there are differing opinions on the effectiveness of such policies.
• Proponents of free speech in general often cite similar sentiments. Trying to kill an idea is usually not only futile, but it can also often imbue that idea with an allure it might not have otherwise had, especially if propaganda condemning it is flawed enough. Trying to outlaw in idea also kills any criticisms of that idea, often more effectively than the original target.
• This trope is the reason behind Thoughtcrime policies: because an idea resides in the mind of the individual, it can only be quelled if they themselves suppress it.
• Some minority rights movements have adopted the phrase "rest in power" to indicate that the death of a persecuted individual can empower others to keep fighting persecution.
• Domingo Faustino Sarmiento escaped from Argentina to Chile, during the totalitarian dictatorship of Juan Manuel de Rosas. Before leaving, he wrote "Barbarians, ideas cannot be killed" in a big rock. He worked against Rosas during his exile and became president of Argentina years later when Rosas had long been defeated and gone.
• Shortly before his assassination, Thomas Sankara, the President of Burkina Faso, said:
  "While revolutionaries as individuals can be murdered, you cannot kill ideas."
• Before she was executed by the Nazi Germany government in 1943, Sophie Scholl of the Weiße Rose resistance group said: "Such a fine, sunny day, and I have to go... What does my death matter, if through us, thousands of people are awakened and stirred to action?"
• A unique application of this trope was a gun control protest by Phillip A. Luty, who designed an SMG using purely general-purpose materials and equipment. His assertion was that banning firearms was useless since all you needed to obtain one was mere knowledge of firearm mechanics, which could not be banned. Forgotten Weapons goes into detail here.

---