Equivalent Exchange: Difference between revisions

{{trope}}

 

 

Power is [[Magic A Is Magic A|consistent]]. Power is [[Functional Magic|functional]]. Power is [[Spell Construction|not]] [[Power At a Price|free.]]

 

 

 

The object or goal to be traded with Equivalent Exchange must be of equal value to a petitioner. However, how this "equivalency" is determined can be vague. Is the value preset? How valuable it is to the giver? The value to the receiver? Is it purely emotional, or will monetary, legendary, or rare things do? The same penny, handed down from father to son, would be worthless to someone else who just found it on the ground. If a wizard, say, [[Ritual Magic|ritually]] sacrifices a cat to get some magical mojo, which is used: the value of the cat's life to the wizard, or the value of the cat's life to the cat? What measure for value is changed to the whim of the plot.

 

Compare [[Balancing Death's Books]] and [[Mutual Disadvantage]].

{{examples}}

*** In fact Ed himself comes to this conclusion in the manga: you need a soul, and the right one at that. {{spoiler|Now if you don't care about what soul you want, you can make a massive army of homunculi…}}

** The Philosopher's Stone was said to allow bypassing of Equivalent Exchange. {{spoiler|Not true, since the price for the alchemy has already been paid with the sacrifice of souls. Basically, the stone is a massive portable power supply, which lets you create matter from the massive energy stored inside it, seemingly from nothing.}}

** However, one of the central tenets of the manga and a sign of the development of Alphonse and Edward as people is that {{spoiler|no matter how much they try and apply the rule of equivalent exchange to life, something is always missing. By the end they vow to give 11 back to every person or thing they take 10 from, thus making the world richer.}}

*** The first anime has this exact same thing happen, though it is applied differently. Almost everything Ed and Al try to do only makes things worse, instead of better, because of their belief in the theory of Equivalent Exchange, due to the fact that the many variables in life always affect the outcome. This is driven even further by {{spoiler|Dante's [[Hannibal Lecture]] to Ed towards the end, where she picks apart this theory and exposes its flaws}}. Unlike the manga, though, the lesson from it is slightly different.

** This is a plot point for all three scenarios in the game, as protagonist Emiya Shiro has to fight, but the only magecraft he is skilled at is far beyond his capabilities. Whenever he uses it excessively, blood loss (and death) is inevitable.

** A double subversion occurs when Shirou gets the ability to use {{spoiler|Unlimited Blade Works}}; his mana cost for Gradation Air (Projection) becomes zero while inside it, but he still needs to gather mana in order to cast it. [[Deus Sex Machina|No points for guessing where he gets that mana.]]

** Another subversion is Rin’s Jewel Sword Zelretch, which lets her use strong attacks indefinitely by absorbing mana from alternate realities.

* In Sci Fi Harry, the main character may perform telekinesis, but someone nearby will die as a result.

** For the record, Yuuko accepts items (or intangibilities) that have both real and emotional power: Kurogane's sword is both a precious reminder of his family and a powerful weapon; Fai's tattoo is imbued with powerful magic for his own safety; and Syaoran and Sakura pay by giving up a portion of Sakura's memories - those which contain Syaoran. This means their previous relationship is sacrificed forever. Syaoran has been edited out of the memories the feathers contain. For example, Sakura can remember the events of her last birthday party, but one seat is mysteriously empty, and there's an odd pause in the dialogue whenever someone would have otherwise said Syaoran's name. One time Sakura almost manages to put two and two together, but passes out and loses all memory of her deduction due to this price. It's not flat-out impossible for Sakura and Syaoran to have a relationship after paying the price, but it has to be rebuilt from the ground up.

** Interestingly, you apparently don't need someone to trade with. {{spoiler|Clow and Yuko gained entry into the cycle of reincarnation for the clones by giving their lives up to... nothing in particular. Watanuki and Syaoran Jr. escape from a pocket dimension in exchange for freedom from The Shop and the ability to remain in one world for very long, respectively, again not actually selling it to anyone in particular}}.

* ''[[Hibiki no Mahou]]''. Oh dear, ''Hibiki no Mahou''. If you want to use magic properly, you need to sacrifice an aspect of your being, like ability to dream, age, or memory. No wonder why magic practitioners are declining.

* Although it's not too much of a regular magic as it's more of a one-use, people at ''[[Hell Girl]]'', when contracting Enma Ai, can send one person they dislike immediately to Hell - with the price of their own souls going to Hell when they die. That's the reason why many people hesitate in first place: going to Hell is a really high price. But then, out of spite, they send their victims into Hell anyways. The lesson is to learn to control your emotions and hatred? or [[You Can't Fight Fate]]? [[Lost Aesop|Who knows?]]

* ''[[Code Breaker]]'': It turns out that {{spoiler|Ogami's powers come from a [[Deal with the Devil]]: for every upgrade he gets, he loses one of his senses. He's already lost his sense of taste, but "fortunately" Code: Emperor has chosen to take his newly acquired sound powers rather than his hearing... although there's still five upgrades to go...}}

* The second arc of ''[[Naruto]]'' started off with Gaara dying, but he was an immensely popular and critical character so he needed to be revived. Enter Chiyo, who has a ninjutsu capable of reviving the dead. To avoid this being used to prevent every death in-series, the jutsu was equivalent exchange: the user sacrifices their own life to resurrect another.

** This is also how wishes granted by demons run. They usually come with a myriad of attached strings that cause grief and misfortune to the person making the wish.

* In ''[[Puella Magi Madoka Magica]]'', the wishes that get fulfilled in exchange for the girls becoming magical girls are guaranteed to cause an amount of despair equal to the hope they bring.

** To gain the incredible powers of God's Right Seat, a magician must give up his or her ability to use normal spells. {{spoiler|Acqua of the Back gets around this because his Divine Mother's Mercy removes limitations and secondary conditions. Fiamma of the Right gets around this by brainwashing Index to do the spells for him.}}

 

* In the British ''[[Transformers]]'' comic, if someone travels back in time, someone from the destination period vanishes into Limbo while the traveler is there. Attempts to avoid this will eventually get you eaten by a time warp.

* In the Pre-Crisis DCU, the Guardians of the Universe purged themselves of evil, only to find that the evil had to go ''somewhere''. They [[Sealed Evil in a Can|sealed it in the same universe where they sent most of the magic]] to ensure that the [[The Golden Age of Comic Books|Golden Age]] [[Green Lantern]] would be around to deal with it.

* Storm's weather-controlling powers in the ''[[X-Men (Comic Book)|X-Men]]'' comics are given a similar limit to explain why she can't turn the world into a paradise, or at least bring relief to disaster-stricken areas. The first time she tried that, she successfully ended the drought in her village - only to discover that, since the moisture she'd drawn upon had to come from somewhere, she'd caused even worse droughts to strike the rest of the world.

 

 

* In ''[[Conan the Barbarian]]'', Conan is mortally wounded by his crucifixion on the Tree of Woe, so his lover Valeria convinces the Old Wizard to work a healing spell to save him from the brink of death. The Wizard warns that the gods demand a price for this sort of thing, and she says she'll pay it. When she's later shot with a snake arrow by Thulsa Doom, she decides that her death is her payment. Whether that's true is not revealed, but it seems logical given the [[Crapsack World|bleak universe]] of the film.

* The magic [[Time Travel|time traveling]] scepter of ''[[Teenage Mutant Ninja Turtles (film)|Teenage Mutant Ninja Turtles]] III'' required an equal number of people (of roughly the same weight, which didn’t come up) to travel in each direction. While the movie is [[Fanon Discontinuity|not all that popular]], it did make for [[Hilarity Ensues|some interesting events]] going on while the Turtles were back in Feudal Japan.

* A relatively benign example of this trope occurs in ''[[The Secret of the Magic Gourd]]''. Rather than a life for a life, the Magic Gourd uses magic to swap Wang Bao's blank failure of a test paper with the high-scoring test of a fellow classmate. Being his typically dumb self, Bao Hulu doesn't even bother to change the name at the top of the test, which gets Wang Bao in trouble for cheating.

 

* Christopher Paolini's ''[[Inheritance Cycle]]'': The ''[[Functional Magic|entire magic system]]'' of the series is wrapped up in this. Doing something with magic takes the same amount of energy as doing it without magic would have done. And if you try casting a spell that takes up more energy than you have, you die.

** This is what he says, but at one point, Eragon breaks the calves of dozens (maybe hundreds) of soldiers and doesn't die. And how much energy does it take to make a blue fireball without magic?

** And certain spells are just flat-out impossible, presumably because they take far too much energy, or simply cannot be done. For example: Eragon is warned to never try to bring people back from the dead; beyond death, there's just something that magic has no effect on; an attempt would drain the mage of all his life in one go and accomplish nothing. Trying to see the future or the past is a bad idea as well.

** Although in the second book, the young woman running the Varden finds some wiggle room in the rules: doing something with magic takes less ''time'' than it would otherwise, therefore magic-users can outperform in tasks which are complicated but low-energy. And that's the story of how the Varden climbs out of a financial hole by {{spoiler|producing and selling finely made lacework for ladies garments}}.

* This also comes up a lot with magic in the ''[[Discworld]]'' books, where it is referred to as the Law of Conservation of Reality. For example, to teleport someone from one side of the disc to another, you may need to have an equivalent weight to teleport back to where they came from. This is mainly to deal with conservation of momentum; because the Disc rotates, different points on its surface move at different velocities relative to the Hub. Teleporting without such a counterweight means that if you move very far, your velocity relative to your immediate surroundings tends to kill you. But you can do it!

** This is still an imperfect science, and when the wizards of Unseen University try it to retrieve Rincewind in ''Interesting Times'', he's hit on the head by all the crap they piled up to equal his weight, going the other way.

* ''[[Vurt]]''. Things are swapped between the real world and the vurt world on the basis of their value. The characters are keeping a weird tentacled creature because it was somehow switched with the protagonist's sister, and they're trying to figure out how to get her back. At one point, he wants to bring a object back to reality, so he leaves something of sentimental value behind.

* Blood-magic in George Martin's ''[[A Song of Ice and Fire]]'' works this way;

** Despite that the balance is well-known in-universe, it didn't stop people from trying to cheat. Recluce itself, for example, was protected by a navy of Order-infused ships...and every time they replaced one, it was with a larger, more powerful ship that required more Order.

* The novels in the [[Star Wars Expanded Universe]] emphasize that the [[The Dark Side|Sith]] path is one of sacrifice, i.e., ''demolishing'' attachments instead of the Jedi path of ''avoiding'' attachments. Since the Sith draw power from pain and rage, easy or pleasant trade-offs aren't in the picture.

** Fatigue-banishing spells exist, but they cannot be re-used indefinitely, and the rejuvenation they provide can be quickly lost if the person experiences more stress.

** Training also seems to extend endurance within limits, much as people who physically train increase athletic endurance to a point. Tiercel makes this analogy: “...you're flexing abilities you've never used before. You have to build up your endurance. I'll bet you've got a headache just from this afternoon's work.”

** It's later explained that the sacrifice which made him immortal wasn't actually his wife and children. It was ''his own humanity'', which he lost through the expedient of killing his wife and children.

*** And if he ever tried to act like a compassionate human being again by engaging in an act of life or Healing, his immortality would be forfeit.

** We're later introduced to people with healing spirit stones. They can heal the wounds of others by taking them on themselves, although the healers have a slightly improved healing rate.

* In ''[[The Neverending Story (novel)|The Neverending Story]]'', AURYN grants humans the ability to make their wishes come true, by rewriting reality in Fantastia so that it always was so. In exchange, AURYN takes away a memory of the Outer World from the human with each wish. They start off reasonable enough (trading the memory of being fat and scared for a more heroic figure), but eventually descends into taking more and more precious memories, no matter how selfish the wish is (the memory of being from the outer world, the memory of one's parents, the memory of one's own ''name''). In the book, the wishes don't even have to be spoken, either. If you want something badly enough, AURYN will sense it, grant that wish and take a memory with no effort on your part.

* In [[Robert Silverberg]]'s early novel ''The Time Hoppers'', time travel is done by exchanging matter between the present and the past; when a human is sent back, an equivalent mass of air has to be brought forward.

* In Cornelia Funke's ''[[The Inkworld Trilogy]]'', characters can be read out of books into the real world, but not without someone or something from the real world taking their place

* ''[[The Wheel of Time]]'': While use of saidar is more or less free, the Aelfinn and Eelfinn operate on this basis, and from most non-main characters important things like valuable knowledge, cooperation and items must be bargained for, often with extensive negotiations over the price the heroes must pay.

 

* Ben's healing talent in ''[[Carnivale]]'' worked by drawing [[Life Energy]] out of the surrounding area. Cure a little girl of polio, the crops wither as she skips away through the cornfield. Heal a broken arm, a bunch of fish go belly-up in a nearby pond.

* Chloe Sullivan on [[Smallville]] got a similar power in the sixth season finale (in this case, she died and came back to life). In the Seventh season, it is explained that she can heal non-fatal wounds so long as she herself takes on that wound (i.e. to heal a paper cut on Jimmy Olsen's finger, her body compensates by receiving a wound of similar size on the same spot on her body).

* In ''[[Kaizoku Sentai Gokaiger]]'', the [[Series Goal|Greatest Treasure in the Universe]] has the [[Reality Warper|power to change history and reality]], and confirms that it could be used to erase [[The Empire]] from history...but doing so would ''also'' [[Ret-Gone|retroactively erase]] all of the [[Super Sentai]] from existence. The Gokaiger end up deciding not to do this, since the Sentai mean too much to humanity and it isn't their right to make that call for the entire planet.

 

* The concept of [[Call It Karma|Karma]] in many religions.

* In [[Euripides]]'s ''[[Alcestis]]'', Admetus' wife, Alcestis, offered to [[Balancing Death's Books|die in his place]]. And then [[Deus Ex Machina|Heracles showed up]] and ''[[Did You Just Punch Out Cthulhu?|beat up]]'' ''[[The Grim Reaper|Death]]'' to save her so that there could be a happy ending. Honestly, didn't these Greeks read Orpheus?

 

* Most magick in ''[[Unknown Armies]]'' works this way. The "value" of certain actions varies based on what kind of adept you are. Typically an adept gets a "minor charge" for some kind of ritual that's easy enough to be performed every day or so, a "significant charge" for doing something very difficult and painful, and a "major charge" for doing something nigh-impossible. And even the magick that seems to be free usually isn't. In [[Unknown Armies]], ain't nothin' come for free.

** There's even an in-game term for the concept in UA: The Law of Transaction.

* Present in the TCG [[Magic: The Gathering|Magic the Gathering]] to an extent. Every spell has a cost. Most are simply [[Mana]] drawn from the land, but others require a life (yours or your creatures), the land itself, or even time (skipping a turn). Several cards will actually kill you if the cost is too much for you to afford.

** Perhaps the most famous example of this is Necropotence. You don't draw normally near the beginning of your turn; instead, you may pay X life to draw X cards at the end of your turn. However, this particular exchange turned out not too equivalent: both cards with this effect proved to be broken beyond imagination.

* In ''[[Geist: The Sin Eaters]]'', a Sin-Eater can come back from the dead easily (yes, [[First-Episode Resurrection|more than once]]). Problem is, in addition to the act knocking a chunk off your [[Karma Meter]], your [[Our Ghosts Are Different|geist]] is going to draw that life force directly from someone else. And when you wake from your brief dirt nap, your face is covered in an ectoplasmic caul that conveys ''all'' the details of that person's death.

* Several of the magic systems in ''[[Legend of the Five Rings]]'' work this way. Shugenja do not so much manipulate the elements themselves as convince elemental spirits to do them favors, and much of their duties involve making sure said spirits are happy. ''[[Black Magic|Maho]]'' is directly powered by the shedding of blood - but good news! It doesn't have to be ''your'' blood.

 

* The ''[[Monkey Island]]'' games have this as an element of Voodoo magic. In ''[[The Curse of Monkey Island]]'', Guybrush needs to find need a diamond as big as or bigger than the one that turned his fiancé to stone. In ''[[Escape from Monkey Island]]'', he needs to make an Ultimate Insult talisman as large as or bigger than the original in order to counter its effects. (No explanation is given on why his enemies can counter Guybrush’s insults even when he has the larger talisman, although it ''is'' only the ''second'' biggest monkey head Guybrush has ever seen...)

* Whenever the Nameless One from ''[[Planescape: Torment]]'' {{spoiler|dies and comes back, someone else somewhere on the Great Wheel dies as a result, becoming a tormented shadow whose only desire is to hunt down the Nameless One and kill him again}}.

*** Then, double subverted with the {{spoiler|Pillar of Skulls}} and a particular (semisentient and evil) book of magic, which soon begin to ask for things ''aside'' from and greater than, just for an example, a taste of your flesh or you to commit some minor evil act.

* The ritual of Soul Exchange in ''[[Valkyrie Profile]]'' allows someone to sacrifice their own life to bring someone else back. However, it won't work on someone who died by using the same ritual, and one character ends up undead for attempting this.

** Don't expect to ever have to pay that price [[Gameplay and Story Segregation|yourself]] though.

** Examples include the Life Tap spell (converts health into mana points), Health Funnel (heals your pet demon at a cost of your own health), Hellfire (which burns you as well as your enemies), and Ritual of Doom (summons a powerful demon; originally one party member would die upon completion, now one member is simply badly wounded). Other spells are fuelled with Soul Shards, gained by killing foes with a particular spell.

*** Doomguards don't even require the ritual of summoning or sacrifice of health anymore. Just hit a button, and BOOM he's there fighting on your side for 45 seconds.

** Lore example: In the ''Ashbringer'' comic, Darion Mograine stabs himself with the titular sword to free his father Alexandros's soul from the Scourge's hold, becoming a Death Knight himself. "I love you, Dad..."

* ''[[Dragon Age]]'' mages can inadvertently perform minor displays of magic effortlessly (Wynne discovered she was a mage when she accidentally set a bully's hair on fire when she was only nine years old). This is usually how young potential mages are discovered by the Templars. More powerful spells and rituals require outside sources of energy. Lyrium, the [[Green Rocks]] of the setting that are the ''[[Dragon Age]]'' setting's source of magic, is usually distilled into a consumable liquid form for this purpose. [[Blood Magic|Blood Mages]] can use [[Life Energy]] (theirs or others' it doesn't matter) instead; this also lets them perform blood manipulating feats that non [[Blood Magic]] cannot, such as [[Mind Control]] (controlling blood in the brain?) and ripping the blood out of their enemies' pores.

** Also, another case with Blood Magic is that for a mage to first be able to use it, they have to make a bargain with a Demon to gain the power. Now, what each bargains requires changes from person to person, but most cases end with [[Grand Theft Me|the Demon possessing the Mage]] and turning them into [[And I Must Scream|an Abomination]].

* In ''[[Quest for Glory]] I'', "Every curse has an equal and opposite countercurse."

* Equivalent Exchange is one of the major rules of magic in the [[Nasuverse]] both in the practical (a spell needs to take its energy from somewhere else) and the social sense (a magus will never do someone a favor without expecting something in return).

* In ''[[Final Fantasy XII: Revenant Wings]]'' summoning Yarhi siphons part of your Anima, the part of you that feels, which is why all the Aegyl who regularily use Yarhi to protect them selves for random monsters appear rather emotionless. {{spoiler|Their "god" draining their Anima for himself is a bigger factor in this though.}}

 

 

* The fact that all magic has a price is used repeatedly in the [[DCAU]]. In one notable case in ''[[Justice League Unlimited]]'', Circe's price for releasing a [[Baleful Polymorph]] curse she had on Diana is something from Batman he can never regain once lost... ''[http://www.youtube.com/watch?v=uoRundeX6O0&feature=related his dignity]''.

** It was still a [[Crowning Moment of Awesome]], though. Because even when giving up his dignity, Batman's that much of a [[Badass]].

** And then {{spoiler|Bender [[Nice Job Breaking It, Hero|makes an uncorrigible paradox]].}}

* Eric gets a lecture to this effect from Dungeon Master in the "Day of the Dungeonmaster" episode of ''[[Dungeons and Dragons (animation)|Dungeons and Dragons]]''.

 

** There's actually [[wikipedia:Conservation law|quite a few of these]]. Some are played straight, but others are subverted and only hold true under most circumstances.

** [[wikipedia:Noether's Theorem|Noether's Theorem]] shows that there's a one-to-one correspondence between conservation laws and physical symmetries. Conservation of energy is due to time-invariance, so as long as physical constants don't change, it will exist.

** Technically, increasing entropy is a strict conservation law. If you kept track of all possible outputs for a given set of inputs, the total entropy would remain constant. It's just that it's effectively impossible to keep track of it all, so you have some set of "possible" outputs that includes the real set, and has higher entropy.

** 6 CO2 + 6 H2O + Energy -> C6-H12-O6 + 6 O2

*** For the less chemistry-inclined: 6 Carbon Dioxide + 6 Water + Energy -> 1 Sugar + 6 Oxygen.

**** And the [[Bunny Ears Lawyer|Rubisco]], which sucks at its job as a catalyst of that overall reaction, but is the only one that works.

*** C6-H12-O6 + 6O2 -> 6 CO2 + 6H20 + Heat. [[QI|Explosion in a custard factory]].

** More generally, while any human is capable of performing similarly superhuman feats, untrained Muggles can only do so under great stress and at the cost of shutting down certain vital functions temporarily, as well as directly damaging their bodies.

* In a meta example partially related to the above, to achieve anything in life it is necessary for certain things to be used to reach this point. To breathe you must expend the energy needed to inhale oxygen into your lungs, to become successful at something (without relying on luck->chaos->entropy) you must devote a large amount of time to study your chosen field et cetera.

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