Magic A Is Magic A



""We don't ask that you stay within the bounds of physics, but at least follow the rules you freaking made up.""

- Cracked, 8 Classic Movies That Got Away With Gaping Plot Holes

Works heavy on speculative elements, such as Science Fiction and Fantasy, often have an assortment of fantastic intangibles we cannot even dream of encountering in Real Life—yet act in a completely consistent way, as if governed by imaginary rules of physics.

Or at least, they do, if the writer knows what he's doing. No matter how fantastic the events in a piece of fiction, their Internal Consistency is what makes or breaks the Willing Suspension of Disbelief. You can have the tech guy of La Résistance explain in oblique terms involving the word "nano" why the Evil Empire's fairy dust superweapon needs an hour to recharge after activation, and the audience will nod its collective head and smile; but if you later have that superweapon fire twice in succession, you just made a Plot Hole and they'll all be at your throat.

This is such a fundamental part of an audience's perception of a story that if you establish a fictional "rule" that isn't quite like reality, and then later break this law to make things act the way they actually would in Real Life, people will likely be distraught. Whether it's realistic doesn't matter. Even whether it's explained at all doesn't matter: depending on your audience, even "it's magic!" can be a satisfactory explanation, as long as the magic behaves consistently.

The substitution of mere internal consistency for a bona fide logical explanation is a Necessary Weasel of Speculative Fiction. Without it, any instance of a wizard casting a fireball would quickly degenerate into an Info Dump of quasi-physics and pseudo-science. However, much like any other trope, too much of it can be unhealthy. If a plot-significant element behaves in a consistent yet markedly unrealistic way, you can expect even the most patient audience member to eventually want some answers about why it does, if only because they assume things are Like Reality Unless Noted.

Consistency itself, too, can be taken too far; or rather, it can be misapplied. It's too common to see rules being "overdone" to the degree that it's their spirit, rather than their letter, which cannot be broken, essentially as if the universe was playing favorites. This is how you get phenomena like Plot Armor: Saying that no weapon can break through the Armor of White Legend is one thing; having a whole battalion of enemies surround the wearer of this armor and futilely shoot volley after volley of arrows at them, without stopping to think of any other strategy at all, is something else entirely.

It's possible to break consistency without damaging the Willing Suspension of Disbelief. It takes work- basically, the work of making a believable case that the violation did not happen out of nowhere. One way is to have the characters themselves notice the inconsistency; this only reinforces that it is unusual and there might be an explanation for it somewhere. If none ever ends up being offered, at least it relegates a glaring Plot Hole to mere Fridge Logic. After all, if Magic is actually like science, then the theory will likely be wrong sometimes and will have to be revised in the same way earth science.

This trope derives its name from Aristotle's Law of Identity, which claims that "a thing and itself are the same thing" and marks an important contribution of Captain Obvious to modern rational discourse. The title references the law's well-known symbolic formulation, "A = A", which is probably due to German mathematician and philosopher Gottfried Leibniz.

Related to Wrong-Context Magic, when someone explicitly has the ability to circumvent it. See also Beyond the Impossible where internal logic is broken for some reason.

See also Minovsky Physics, which is a fictional physics with extremely detailed laws that makes it look like real physics, as well as the Cool of Rule. Contrast New Rules as the Plot Demands and How Unscientific; also contrast Gameplay and Story Segregation, which is an entire category of notoriously common Video Game violations of this trope.

Anime & Manga

 * Read or Die sets the arbitrary yet consistent rule that only the most skilled paper-manipulators may use paper that gets wet.
 * Fullmetal Alchemist never gets into the "nuts and bolts" of how one learns alchemy or gets it to work, but we are shown though repeated example that it requires a great deal of research, practice and the use of inscribed runes or circles to make it happen. There is also the constantly repeated rule of Equivalent Exchange, that for the alchemist to create something, he or she must destroy something of equal value (in practice, this means just having the necessary raw materials at hand - the act of construction itself doesn't seem to "cost" anything.

In fact, the author's notes at the beginning of the original manga emphasize that the series was originally intended to showcase a B-movie style version of real-life alchemy, without so much emphasis on the actual science behind it.
 * Death Note: This is one of the central tropes of the series, with Light Yagami pushing each of the rules for using the eponymous Death Note to its breaking point, while his adversary L uses every clue available to determine the limits of "Kira's" powers. Some of the rules themselves are written out in an explicit, detailed manner in the first episode; others are puzzled out over time, and shown briefly in Eyecatch segments; a full list is here.
 * Worth noting is that some of these rules are introduced before they actually become relevant to the plot, while others never become relevant at all.
 * When The Simpsons comic book did a parody of it, they got rid of the impossible situations rule. Which led to, among other things, Flanders getting pecked to death by a flock of flying penguins.
 * Ranma ½ magical transformations have a set of basic if very generalized rules to purposely avoid complicated minutiae ("I don't think about it, and neither should you!") despite whatever fans say.
 * Nasu Kinoko's works have a nasty habit of setting up incredibly complex and detailed rules about The Verse... then having a character with some really rare ability break those rules. Of course, only that character alone can ever do it (and probably not more than once), otherwise it's completely consistent.
 * One of them: Nothing can reverse being a vampire, once you pass a certain point. Ever. Period, end of story. One character is an ex-vampire, through said convoluted spoilers. One character is almost at that certain point, and one character comes within inches of it
 * There is one thing that can reverse vampirism: death. The ex-vampire in question, for convoluted reasons, simply didn't stay dead.
 * Another example is that you can't just make stuff with magic and expect it to stay around. It'll be gone within minutes. Unless you happen to have mastered the First True Magic that is, or you're Shirou and have a Reality Marble that allows you to break that rule.
 * Reality marbles themselves are either a very good example of this trope or a glaring break from it, depending how you look at it. But ultimately the concept boils down to a detailed and structured set of rules for breaking a detailed and structured set of rules.
 * It's stated in-universe that the point of reality marbles IS breaking the rules.
 * Needless to say, the rules in the Nasuverse are extremely complicated to the point of Mind Screw. The fact that more than a few rules actually contradict others really doesn't help.
 * Mahou Sensei Negima does well with this by only ever explaining the nature of strategies and techniques, and leaving the actual science of magic for the Lexicon Magicum Negimarium. Even still, the eponymous Negi makes it clear that he's never heard of anything like a money tree and that Love Potions aren't common and are unreliable because magic wasn't meant to be used like that (later it's made clear that Love Potions are completely illegal in Magical society). It doesn't stop Love Is in the Air moments from occuring (often hilarious).
 * Also, there is at least one rule Negi can break by kissing hard enough.
 * Well, technically, no one even knew if there was a rule concerning that, and considering that, he actually has a surprising amount of leverage.
 * In other words, magic still follows the laws, but one of those laws is.
 * It doesn't matter much because in the situation of Negi and Jack Rakan, whenever they break a seeming rule, it is brought to our attention, such as.
 * Code Geass has Lelouch test out via experiment the constraints of his Geass. The show mostly sticks to the established rules, but does leave vague the duration of a command.
 * The duration is "however long it takes to follow the command"; this has created a bit of Fan Wank as some believe that despite Word of God saying it only triggers when
 * For all the magic and curses flying around in Tsubasa Reservoir Chronicle and xxxHolic, it is made indisputably clear that the one rule of that multi-verse is that the dead don't come back. No matter what you pay. Well, at least in the manga.
 * Hunter X Hunter does this with the Nen-system. Going further, while Nen itself has its own rules and limits, specific abilities can also have rules of their own set in place by their creators. Examples of such rules can be placing limitations on how and when an ability can be used. Further, due to the general rules of Nen, setting such limitations can make the actual ability far more powerful. For example, protagonist Kurapika creates powerful attacks with the limits that they can only be used against the Phantom Troupe and he will die if he mis-uses them. These limitations allow him to take on the most physically powerful of his enemies one-on-one without difficulty.
 * The rules of Immortality in Baccano!! are made clear cut in episode 7 (and even earlier in the books). The rules in the book are elaborated on a bit more (primarily because at least two immortals have been spending 200 years testing the constraints), but the principles are still the same:
 * The only thing that can kill an immortal is to be "devoured" by another immortal.
 * Any immortal who consumes another attains all of their knowledge and memories (including muscle memory).
 * No false names in the presence of other immortals.
 * NEEDLESS: One Needless, one Fragment. It's consistent throughout the story, with certain Fragments can imitate the effect of other Fragments to some extent, i.e. Kana's Flamethrower is as good as the power of a Fire Needless.
 * Which is rather broken in itself.
 * Each episode of Gunbuster actually has a little "science lesson" short that explains a certain aspect of the show's universe, laying out the physics behind it.
 * In Majokko Tsukune-chan, the Cute Witch heroine explains that while she can reverse her magic spells, she can't reverse any collateral damage that results from said spells. Since this is a Gag Series, Hilarity Ensues.
 * A certain middle school class in Another must deal year after year with a curse that will potentially kill members of the class and/or their immediate loved ones. This goes on for twenty-five years, more than long enough to determine many of the rules that govern the curse. For instance, the curse only takes effect with the school's town. The one time a death appears to be an exception the actual cause of death was an injury that occurred before they even left.

Comic Books

 * The Exiles version of Mimic had a very specific brand of Mega Manning:
 * He can mimic any power (Up to, and including the Phoenix Force)
 * He has to be within a certain range of the person he's mimicking. E.G., If there's no one nearby with a healing factor, he can't give himself one. If there is, he can.
 * He can only mimic five people's powers at any one time. If he wants more he has to "switch" one power set for another.
 * Each power he mimics is at approximately half the strength of the original user.
 * He can mimic a power pretty much instantly, but it fades very quickly if he doesn't spend a prolonged period of time (about six hours) in relatively close proximity to the person he's mimicking.
 * Superman is an interesting example. When he was first published in The Golden Age of Comic Books, he was simply "leap an eighth of a mile or hurdle a 20 story building", "lift tremendous weights", "run faster than an express train" and "Nothing less than a bursting shell could penetrate his skin", or as later adapations more eloquently put it: "faster than a speeding bullet, more powerful than a locomotive, and able to leap tall buildings with a single bound". Then, The Silver Age of Comic Books started a massive Power Creep, Power Seep, with his abilities including powers as ludicrous as Super-Ventriloquism and Super-Weaving. It wasn't until later when his powers finally settled in the most accepted set nowadays: flight, invulnerability, super-strength, super-speed, super-hearing, X-ray vision, heat vision, and super-breath.
 * Jesse Custer, from the comic Preacher (Comic Book), possesses the Voice of God, which cannot be disobeyed. While this really falls more under the purview of divine power, it is not without its limitations:
 * First, Jesse must be physically and mentally able to speak. If he's gagged or delirious, no Voice.
 * Second, the subject must be able to hear Jesse. Jesse's recurring nemesis, Herr Starr, managed to escape Jesse's voice simply by covering his ears and repeating the word "no" over and over.
 * Next, the subject must be able to understand the order Jesse is giving. In one instance, Herr Starr takes advantage of this by sending hitmen to kill Jesse that didn't speak English, and it's probably worth noting that wild animals don't speak any kind of human.
 * Finally (and this bit's important), the subject must be able to actually do what Jesse has told them to do. Telling someone to fly off the side of a skyscraper doesn't mean that they can suddenly flap their arms and defy gravity. Telling them to "try," on the other hand, will have more favorable, or at least messier, results. Because of this, Jesse has disposed of one opponent by telling him to go to the beach and count sand (and he does) & evaded a crackshot marksman at point-blank range by commanding him to miss (this also lead to Arseface's origin story—Jesse told his dad "go fuck yourself" with the Voice, and the man had to comply. And then shot himself in front of his son.)
 * Fables is a bit confusing. All Myths Are True, and exist in another universe. However, Nick Slick (apparently the devil) and the Frankenstein monster seems to have always existed in the real world, and even mundane world wolves appear to have a complex language and even a religion, implying that they're far more intelligent that real-world wolves.
 * Partially resolved in that over the course of the series it becomes apparent that it is not our world. Jack of Fables makes is much more noticeable as it shows superpowered abstract entities do exist in the Fables universe.
 * The Green Lantern Power Ring should be able to avoid this, as it is advertised as being capable of anything the wearer can imagine. People still complain when it does something exceptional, though, mostly because it stands out as being extremely unusual. Of course, as has been pointed out, most of the Green Lantern Corps has the imagination of a goddamn potato.
 * Runaways features the Staff of One, which can do practically anything (save bring someone back to life). However, its spells can only ever be used once, and attempting to cast the same spell twice would do something random. Despite this, Alex Wilder once got hold of the Staff and managed to cast the same spell repeatedly; this hinted at a loophole where you could get a similar or identical effect by using a synonym or the same word in another language. In the first Runaways/Young Avengers crossover, Nico took advantage of the Vision's on-board thesaurus and language capabilities to wreak utter havoc.
 * Subverted in Matt Wagner's Mage arc; in The Hero Discovered, Kevin Matchstick's mentor Mirth told him that "Magic is Green." Subsequently, Kevin's various magic feats are invariably depicted in a greenish hue. In the sequel, The Hero Defined, Wally Utt said that Kevin was taught "Magic is Green" so he could visualize magic more easily. As Utt revealed, "Magic isn't any color. Magic is color!"

Film - Animated

 * Disney's version of Aladdin puts rules on genie magic. They can't kill anyone, force someone to fall in love, or bring people back from the dead ("It's not a pretty picture; I don't like doing it!!!"). Genie doesn't mention it at first, but also eventually adds that they can't use their magic to serve themselves.
 * The Animated Series added that mixing different kinds of magic is a bad idea, because it produces unpredictable results. This is used as a reason why Genie can't just undo any magic used by villains. It's also hinted that lamp-bound genies are more powerful than free ones, presumably because the bound ones have wishes to grant.

Film - Live Action

 * Richard Donner directed the first Superman movie using the word "verisimilitude" as the production motto in scripting and crafting the film. They devoted a lot of their effort to figuring out how to have things make sense within the ludicrous framework of the premise and plot. Why doesn't Superman solve all the world's problems? Jor-El's dialogue explains (piecemeal) that there is an intergalactic law not to interfere in the course of another planet's history, this rule having been put into place as the result of the early history of "the twelve known galaxies" being rife with warfare due to interference (presumably resulting in stringent vigilance for that sort of thing now, creating the potential for the intergalactic equivalent of an international incident). He is already bending the rules just being Superman in the first place. If the name "Superman" was invented by the media, why is there an S-logo on the outfit? The fancy traditional attire of Kryptonians included family crests in a chest insignia, and the symbol on the seal of Jor-El's clan coincidentally happens to look somewhat like an S. And so on.
 * One of Donner's criticisms of Richard Lester's Superman II was that it gave Superman a variety of powers that he'd never had before, including teleporting, telekinetic beams and, well, the power to pull off a cellophane "S" shield and throw it at your enemies. The audience has no trouble accepting a man who can shoot laser beams from his eyes or start hurricanes with his breath, but will immediately balk when the fictional boundaries of his abilities are overstepped.
 * In Transformers, one of the implied consistencies (enforced by Michael Bay) is that the robots don't do any of the "mass shifting" that has permeated all of the prior incarnations. The Robots have to fit inside their vehicle modes, no more and no less. This resulted in Optimus being a larger semi-truck model to allow for a bigger robot and the largest robot in the first movie, the huge helicopter Blackout, had a hulking robot form. They figured by keeping consistent with that, they could manage the (more difficult to accept) mass shifting of the All Spark because it was used as something special and not as a generic power of all the robots.
 * In The Last Airbender, M. Night Shyamalan changed a significant aspect of Firebending so that it aligned better with the other bending arts. In the show, Firebenders could create their own fire, but for the movie, they are now required to have a fire SOURCE to manipulate. As he said, Katara needed a bag of water and Toph needed to be touching the earth, so why don't firebenders need fire? And much like how Katara learned bloodbending and Toph learned metalbending, master Firebenders are able to find a source of energy from their chi and create their own fire anyway.

Literature
""'Are these magic cloaks ?' asked Pippin, looking at them with wonder. 'I do not know what you mean by that,' answered the leader of the Elves. 'They are fair garments, and the web is good, for it was made in this land. They are elvish robes certainly, if that is what you mean." ("Farewell to Lórien", The Fellowship of the Ring.)"
 * Robert A. Heinlein's Waldo and Magic, Inc. run on this trope. "Magic, Inc." uses it more or less conventionally - the magic in the story follows strict rules, which turns out to be important to the plot. "Waldo" is an in-universe example. The title character (after whom remote-control manipulatory machines are named IRL) is an expert technologist and problem solver who is called in when remote power receptors are failing mysteriously. He finds that someone is fixing broken receptors /by magic/, and is told that magic can do anything - no rules. He disbelieves this and proceeds to discover the rules of magic and applies them, becoming a very successful magician as well as technologist.
 * The Heralds of Valdemar series is quite consistent with its depiction of magic and "mind-magic" - which starts to confuse the main characters in some of the later series, when characters from far-distant locales come in with techniques that break rules they thought were unbreakable. In particular, Gates from one location to another always require an arch or similar frame, and a single mage's own power... until an eastern mage shows up and says they've always done it in teams, and that frames are just a convenience for them.
 * The Adept Firesong once gave a speech declaring that most rules and limits of magic were all in the mage's head - they couldn't do something simply because the way they were taught made them think that it was impossible. And indeed, he and others did manage to do things that other mages couldn't - then a few books later he met the aforesaid Eastern mages who treat magic as a science complete with mathematical tools, and is forced to work with a group of engineers in figuring out a scientific approach to solving a magical crisis, proving that there are some real rules out there after all.
 * In John C. Wright's Chronicles of Chaos, there are six different, mutually exclusive paradigms of magic. Working out their relationships and interactions in a form of meta-magic is a major plot point, and the paradigms can, in fact, be charted.
 * The stories of Australian children's writer Paul Jennings often revolve around this trope—each has a Twist Ending which (however disturbing or disgusting) follows logically from the established rules of an item's or character's special power.
 * The Lord Darcy stories by Randall Garrett use self-consistent Laws of Magic to determine what can and can't be done by the characters. Appropriate, since in this alternate world magic is a science.
 * And "witchcraft" is used to refer to doing things that the Laws of Magic say are nonsense - like using willowbark to cure headaches when everyone knows that there's no symbolic affinity between the willow and pain. Magic as Science, and Science as Magic...
 * Though there is starting to be some of what we would consider more normal technological development: a top secret military research project has developed...a flashlight!
 * A few of the simpler rules are explicitly named in the stories. For example, there's the Law of Contagion, which allows a forensic wizard to determine whether a particular bullet was fired from a particular gun. Occasionally hints of greater detail are given; for instance, the bullet has a strong affinity for the gun, but the gun has a fairly weak affinity for the bullet... it's all explained in-story. It's strongly implied that at the higher levels Theoretical Magic is at least as complicated as Quantum Physics; one of the characters mentions that he has only a Master's degree and not a Th.D. (Thaumaturgiae Doctoris) because he couldn't handle the math.
 * The world of Harry Potter leaves out a lot of details about the limits and method of using its magic, and for the most part eschews explanations for a sense of wonder. Some rules are evidently made up as it goes along but the rules are never fully listed outright, which leaves wiggle room for further explanation (e.g The differences between casting "Accio Wand" and "Expelliarmus" on your opponent). Once the rules are listed, they are never contradicted, but it sometimes seems odd that certain magical abilities were never explained before. Since Harry is a teenager raised by muggles and unaccustomed to the world of magic his lack of knowledge is forgivable, while others take it for granted and have little reason to Expospeak about it.
 * There are five specific things that cannot be created by magic (food, love, life, information, and money). Only the first is enumerated in the series, and only in the last book. The other four are via Word of God, though it's implicit from the lack of those things being created by magic. They do explain that there are imitations that can be made (such making objects take on the appearance of life) and there are "cheats" that might be mistaken for breaking the rule (such as summoning already prepared food from one location to another).
 * One of the themes of magic Rowling has in the series is the dead can never be brought back to life, and the time after death is a mystery even to the greatest of wizards. There are several imitations of life, from ghosts, to zombies, to the echoes of people produced by a Deathly Hallow or Priori Incantum. There's also the horcruxes or the Philosopher's Stone, which prevent the person from dying in the first place, but they don't give true immortality because it's conditional on either item not getting destroyed.
 * The Wheel of Time has a convoluted magic system, especially when it comes to differences between males and females and how various weaves are constructed. Another rule states that shadowspawn die if they try to pass through portals.
 * Though it must be said that, convoluted as it may be, the system was perfectly consistent, once the author figured out how he wanted things to work (around the second or third book). Before that, the rules were slightly looser.
 * But note there are other forms of magic—Perrin's wolf powers, Min's viewings, Hurin's sniffing—that don't fit within the rules and confuse the "normal magic" users. Not to mention the whole Horn of Valere thing.
 * It's further complicated by the fact that the setting is full of Lost Technology, Poor Communication Kills and Culture Clashes, and is set after multiple different apocalypses. When something weird pops up, it's anyone's guess whether it seems completely impossible to the current viewpoint character but would be well-known and understood by someone from another country, was commonplace during the Age of Legends and has been forgotten by the present day, or has truly never been seen before by anyone in the world since the last Third Age.
 * Brandon Sanderson's magic systems are regulated to the point of being almost science. In one case, once the series was over and only about half the magic system was revealed, fans were able to correctly determine the rest of the system, based on the science of the parts that had been revealed. Sanderson owns this trope.
 * You can find his essay on the subject here.
 * One-upping that, the "magic" in Margaret Weis and Tracy Hickman's Death Gate series is (pseudo)science, complete with a Techno Babble—filled appendix describing how all of it works.
 * The Endowment magic system from The Runelords books is very much Magic A Is Magic A. Internally-consistent and thought out rigorously well, it was actually one of the inspirations behind Sanderson's ideas for the Mistborn books.
 * Skulduggery Pleasant uses this, with two separate magic systems.
 * Bonus points, as well, for describing pretty much exactly how the magic works—i.e., instead of "he snapped his fingers and a flame appeared above them," it's "she snapped her fingers, felt the spark and heat generated by the friction, and fed it her magic until it grew into a visible flame."
 * Discworld magic hasn't been terribly consistent over the course of the books (Vancian Magic or Mana? It depends how far along in the series you are), but one rule Terry Pratchett has more or less stuck with is the Law of Conservation of Reality, which says that doing something by magic takes as much energy as doing it normally (although there are "cheats", such as where the energy is coming from). This stops Discworld wizards from being all-powerful Reality Warpers, but unfortunately doesn't apply to Sourcerers.
 * Magic in The Dresden Files has a very well-developed and consistent set of established rules. Working within these rules (and finding loopholes) is a major part of the story in most of the books. Among the most common ones:
 * Magic is generated by a variety of sources, primarily living things and emotions. Shown when Harry is trapped in a magic sealing field in an aquarium, and notes that there's still lots of magic inside the field due to the fact that there's a lot of living things inside and that the aquarium is routinely visited by large numbers of people with strong emotions as they witness the animals inside.
 * Magic is effected and fueled by emotions. Powerful emotions like rage, fear, true happiness, etc. can make spells more powerful than usual or even fuel spells by themselves, but any sort of delicate magic, such as complicated rituals, requires total calm lest they backfire and blow your head off.
 * Magic is bound by the laws of physics. Harry's wind spells still need air to move, fire spells suck the oxygen from an area (and the energy can be drawn from ambient heat), and force spells still operate based on Newtonian physics. Creatures with Super Strength are helpless if airborne, for example, as they are at the mercy of physics without anything to push against.
 * Magic is defined by human thought. This is why wizards use a variety of dead languages to cast spells. The words simply help the wizard shape exactly what they want the spell to do in their minds. Amateurs need rituals, lengthy chants, and meditation to do even simple spells while more experienced wizards can do the same with a single word. You use a dead language because the magic becomes linked with the word in your mind. Use the word "fire" for fire spells and you'll be burning your house down within a week. Don't use words, on the other hand, and the magic comes out raw; the one time we've seen this in the books, the person trying it turned into a human TASER while having a seizure.
 * The exception to this are the very powerful or experienced wizards. Senior Council members can potentially cast spells without using words, like Ebanezar McCoy, and the Archive can fling literally dozens of spells off without speaking. Of course, the Archive is the living archive of all recorded knowledge, and knowledge is power. Note that "Ivy" is not a magic practitioner in the conventional sense; normal people can use magic to a limited extent, but it's like a blind person trying to paint. Ivy has the same amount of magical talent as most people. Her immense magical ability is nothing but skill and knowledge, like a blind person painting ten Mona Lisas with their feet.
 * Religious faith has been described as something "like" magic, but not quite. Magic is compared to feeling like electricity, while faith more like a deep ocean. The main use of faith seen is that it can harm certain supernatural beings (most prominently Vampires) and can negate supernatural powers(Micheal's duel with Nicodemus in Death Masks).
 * Using magic physically tires out the spellcaster. Throwing around magic wears one out like doing any other act of physical exertion; dropping lots of energy can make one black out if used too quickly or too hard.
 * Magic can be targeted using connections between objects, i.e. a spell can be targeted against a person by using a sample of hair, skin, or blood, or an object can be tracked by using a small piece of it. This is used throughout the series to do everything from tracking down lost items to eavesdropping on conversations to launching heart-exploding spells at targets. Harry takes this to a rather impressive extent by taking tiny samples from every building, tree, and street in Chicago and making a precise scale-model replica of the city that allows him to work tracking and eavesdropping spells across the entire city.
 * Mortals and certain other entities have will and choice, which are actual forces in the setting. It is what separates humans, the various types of vampires, and other denizens of the mortal world from denizens of the Nevernever. Humans and other creatures with willpower can create circles of willpower that trap, cut off, and contain magic and can hedge out entities without willpower.
 * Physical contact between magically-sensitive mortals generates a detectable field. Making eye contact with a person with strong magical ability triggers a "soulgaze" that shows both participants the true nature of the other. Anyone with sufficient talent at magic can initiate the "Sight" which allows them to see reality as it "truly" is - letting them see magical auras and determine the true nature of creatures and locations - with the downside that the person who uses the Sight will retain that knowledge with perfect clarity (so if you look upon a victim of a psychic mauling or an Eldritch Abomination, time will not dull the edges of the memory).
 * Magic in Rivers of London, at least the type practised by human wizards, appears to be exceptionally rules based and its apparent violation of the laws of thermodynamics greatly worries apprentice Peter Grant.
 * Magic in the Inheritance Cycle is limited by several strict rules that are generally obeyed as the series goes on, the most important of which is that magic always drains the mage who uses it, and the bigger the magic, the more Life Energy is required.
 * Magic in general seems to work off of Newtonian physics. Throwing a small pebble at a certain speed requires as much energy as if you did it by hand. Then you have to consider how far away the target you're enchanting is and even the very wording you're using in the ancient language, all of which can determine how much energy you could spend on a task. This law can get abstract when you're dealing with metaphysical concepts like turning invisible, healing wounds ranging from cuts and bruises to broken bones and birth defects, and amalgamating enough particles of pure gold to be the size of your fist, to the point that experimenting with magic is extremely dangerous because you don't know exactly how much energy it will require, and very well might kill you.
 * Except when it doesn't, eg, dragon riders can borrow their dragon's hit points (and dragons have plenty to spare, since they are quite large). As of Eldest, Eragon learned he could also use the life energy of plants and animals around him. As of Brisingr mages can also use "Eldunari," which allow you to borrow a dead dragon's hit points.
 * The Rules of Magic (or how it works) are seldom explained in JRR Tolkien's Lord of the Rings - the lore and magical words are well outside the ken of the hobbits. Even people who ought to know (such as Elrond) express some ambivalence on the potential effects of, say, destroying the Ring. Still, this doesn't stop fans from getting into debates about whether the Nazgul wore their Rings or if Sauron had them on his person.
 * It also seems that what is considered magic by, say, Hobbits, isn't always thought of as such by, say, Elves, which makes explanations difficult and/or unnecessary.
 * It also seems that what is considered magic by, say, Hobbits, isn't always thought of as such by, say, Elves, which makes explanations difficult and/or unnecessary.


 * This is because, as Galadriel points out, the word for "magic" used by the hobbits covers what to the elves are two distinct concepts, both elvish "Art" and "sorcery" which is the term for the works of Sauron and the Ringwraiths. Of course, even in Sindarin the term for "sorcery" is just the prefix for "dark" or "black" (mor-) thrown on the word for art, lore, or knowledge (gul, thus sorcery or "the black arts," is morgul as in Minas Morgul and the morgul blade.)
 * Additionally, as is made more clear in the Silmarillion, elves simply don't think of what they can do as "magical." It's just a natural ability to them, like carpentry is to a human being—as far as the elves are concerned, they're just better at making things that us weakling humans. Basically, an elven sailor could get so good at sailing that he could make his ship fly. Likewise, the "wizards" (istari) like Gandalf aren't stock fantasy wizards so much as actually a group of minor gods (the same kind of being as Sauron and the Balrogs, actually).
 * It's also worth mentioning that in one of his essays, Tolkien specifically mentioned that in a true "fairy story", magic should never be explicitly explained.
 * A point is made in the Silmarillion that many great works that might be considered magical can only be accomplished once. The great trees: Telperion and Laurelin, created by Yavanna could only be created once; the Silmarils created by Feanor could only be created once. One may presume the One Ring created by Sauron could also only have been created once and it would make sense that reason for this is as given that he put his own power into the ring thus diminishing it in himself. In this respect the act of using one's 'magic' to create a great artifact appears to forever diminish the creator of the artifact.
 * In Patricia C. Wrede's Thirteenth Child, there are three different traditions of magic, but the differences are mostly how you go about it.
 * A rather interesting case in Shadows of the Apt- humans all possess the Art, giving them powers and abilities based on the particular insect-archetype. This is all inherited- if you have Beetle parents, you're a Beetle yourself and you get Beetle Art. There's also Aptitude- either you're Apt, and can use- and learn to create- technology, or you're Inapt and can't even open a door with a spring-latch. However, the Inapt can learn magic- another interesting part being that if you see Art, you know it's Art not magic.
 * Jim Butcher's Codex Alera is a close parallel to Avatar: The Last Airbender. Furycraft is basically bending spelled sideways... though the rules in detail are different, and while strong mastery of more than a single element is rare, it is not at all unique. All the High Lords can do it. A significant feature is that it is an important issue in the series that furycraft can be treated scientifically, and while the limits are stated well, a sneaky enough furycrafter can come up with surprising new twists, yet still within the rules.
 * Actually, the entire premise of Furies came from a bet that Butcher couldn't write a good story based on a Lost Roman Legion/Pokemon crossover.
 * While Merlin in T.H. White's The Once and Future King can display spectacular power (such as causing a tree to instantly grow and bringing about a snowstorm in the middle of summer) he has some clear limits on what he can do. The only two powers to which he has continual access are Insight (being able to see events going on at the present) and Foresight (being able to see future events; part of the latter is due to Merlin's being born circa the late 20th Century and living backward through time). It is stated that Merlin could not use magic to imitate the Great Arts, such as Falconry or Sculpture, as it "wouldn't be fair". Also, Merlin was "given" his magical powers for the specific purpose of helping Arthur prepare for the kingship, which is why cannot transmute Kay into an animal like he does Arthur.
 * The Belgariad has "the Will and the Word" - you gather your Will and focus it with a Word. This uses the same ammount of energy as doing it any other way, but means you can pull in energy from your surroundings and apply it with more flexibility. The exact nature of the word isn't important (though Belgarath chides Garion several times for choosing insufficiently impressive words,) but there does need to be a word.
 * Most importantly, the one thing magic cannot do is "unmake" anything. It can kill and destroy, for that just changes live people to dead people or whole objects to broken ones, but it cannot erase anything from existence. Doing so causes the universe to take massive offense, protect the targeted object, and annihilate the sorcerer. (As a corollary, this means that there is one object any sorcerer can freely unmake - themselves. Several characters have either attempted or committed suicide this way.)
 * It is theorized that many mages who never had ay practical training accidentally killed themselves by trying to annihilate objects. When the group meets a two-hundred year old scholar whose work was ignored because all of his apprentices mysteriously vanished, they find that he is a really nice guy and the worst thing he ever did was teleport an assailant out to sea.
 * In The Name of the Wind, magic is surprisingly mundane and consistent. The most common type, sympathy, follows (really follows) the law of conservation of energy. For example, if you bound two coins, lifting one would lift both, but it would weigh like both, not accounting for the loss of energy (the more similar, the less energy lost). One can use an outside energy source, though (like, say, using a fire's power to move an iron wheel). Sygaldry is sympathy, but based on written runes, and Knacks are individual and very mundane skills (always getting sevens when rolling dice, growing very large fruits). Lastly, Naming is barely explained, but it's rare, far more powerful than sympathy, and described as "fairy tale magic". There is also the even rarer Fae magic, grammarie and glamourie, the art of making things BE, versus making things SEEM.
 * Subverted in the Collegia Magica trilogy by Carol Berg, in that this is certainly how it is taught...whether the true nature of magic follows this trope or not is a different matter.
 * Superpowers in The Grimnoir Chronicles books fall on a grid that is one part The Quade Diagram and one part ROYGBIV. All supers start out with a single power which either comes from one part of the grid or the overlapping of two or more parts. In turn, the kanji brands are two-dimensional sympathetic representations of whichever part(s) of the grid the user wishes to draw power from.
 * Averted in the Shannara series, where it is made very clear over and over that magic is highly unstable and unpredictable, prone to shifting over time from one form to another. Even well known and fairly well understood magics can occasionally have unforseen effects.
 * In the Time Scout series, there are a few rules to time travel that aren't broken.
 * No paradox. Don't bother trying.
 * If you exist twice in the same time, you'll die. It's called shadowing yourself. You can't cross your own shadow and live.
 * The Alex Verus series has a fairly definite set of rules for the powers the mages can use. The author even has a series of articles on his website called the Encyclopaedia Arcana talking about it.

Live Action TV

 * Despite the fact that in part one of The Tenth Kingdom, Wendell's transformation into a dog and of the dog into him is shown through a now-somewhat-dated but still effective slow-morph, his later restoration at the end of the series occurs in only a few split seconds while he and the Dog Prince whirl around in each others' arms and then fly apart with a burst of magical sparkles. The only explanation for this sudden change in the speed of transformation is an attempt to show off the special effects, most likely as a minor example of the Rule of Cool. (More dramatic, after all!).
 * Mahou Sentai Magiranger had a well mapped magical system; there were multiple tiers with 10 words each, but said words could be combined in any which way a character wanted to do different things. The fact that the main heroes were breaking the tier system by the end of the season gave a feeling of "they're more powerful than any magicians in history" instead of ruining suspension of disbelief, due to the usage still remaining consistent within the tier breaking.
 * On the other hand, the US version, Power Rangers Mystic Force, fell prey to the consistency ditching pretty quickly. Whereas the magic syllables were made up words that signified general intent in Japan, they became Harry Potter-copy Latin/Welsh translations in US, making it less of a detailed system and more "use whatever works whether it contradicts previous usage or not".
 * The later series Samurai Sentai Shinkenger has magic called Modikara invoked by writing the appropriate kanji character in the air using their magical paintbrush/cellphone transformation device. Writing the kanji for "rock" (石) will cause a rock to materialize, and writing the kanji for "horse" (馬) will also cause a horse to appear. The kanji also has to be written properly, a fact Chiaki learns early on when his terrible penmanship prevents him from using Modikara because he never learned how to write the kanji for "grass" (草) with the proper stroke order. Genta, who does not have the paintbrush/cellphone, instead uses a text-messaging interface on his cellphone transformation device.
 * Power Rangers Samurai has kept this system, but uses different kanji in some situations.

Myth

 * Any number of superstitions regarding behavior of mythical creatures that "haunt" people. For example, salt keeps evil spirits at bay. Many of those rules are actually very consistent, if you know from what leaps of logic they spring. (Salt keeps food preserved, rot is caused by unclean spirits, ghosts are unclean spirits, therefore salt = no ghosts.)
 * On the other hand, similar things from different cultures and times can sometimes result in a lot of mythological mashups. The result being many different rules that were consistent becoming inconsistent because they're being applied to each other.

Tabletop Games

 * The Expanded Psionics Handbook in Dungeons and Dragons has no less than two sets of alternative rules for running a "Psionics are just different" game - either making them 100% independent of magic (so spell resistance, Dispel Magic and so forth don't work on them), or making them about 45% independent (so you need to make a caster level check to use Dispel Magic on a psionic effect, and your power resistance is 10 lower than your spell resistance). The default (and balanced) setting is the are interchangeable for such purposes and at least 1 setting has psionics as explicitly a separate type of magic.
 * They also have two different flavours of magic, depending on what its source is - Arcane or Divine. Arcane magic comes from wizards memorizing spells and using hand gestures to cast them (and so can be screwed up by wearing armour that restricts your movement and gets in the way), whereas Divine magic comes from the Gods and has no such restriction. Also, for the most part, healing spells are limited to divine only (except for Bards, who do things their own way).
 * Which of course gets rather head-scratchy in some of the official worlds such as Dragonlance, where Arcane magic is totally separate from Divine magic, and yet still comes from gods, and you get it by worshiping them.
 * The entire arcane/divine split is just a convenient Hand Wave to keep wizards in particular from (a) wearing armor and (b) using healing magic (both of which Bards, also arcane casters, do just fine), both purely for purposes of game balance. It's probably best not to try to read much more into it than that.
 * The fluff regarding the difference between Divine and Arcane magic varies by setting, but one very common tendency is that divine magic requires one to act as one's faith would have it (or at least to be able to convince oneself of that), whereas arcane magic have no such compunctions - that highly religious, saintly wizard can one day wake up and decide to become a Complete Monster for his own sake rather than for any god, and it would not impact his ability to cast magic in the slightest.
 * In earlier editions, psionics did not interact with magic. The system was a completely bolted-on addition which barely fit the rest of the game and could be horribly broken when a wizard or paladin, no matter how powerful, was just as vulnerable to a 2nd level psionic character as a peasant. Additionally, the rules for psychic powers required ability score checks against variables and had their own, separate, entirely different mechanic for psychic combat. Defenses against psionics for non-psionicists barely existed. Gaming groups often would rather forget psionicists existed than deal with the headaches you get from averting this trope.
 * There are three set rules for magic in Exalted: "No time travel", "Once Exalted, you cannot Un-Exalt." and "No resurrections." Of course, this being Exalted, those rules exist mostly for Solar Circle Sorcerers to kick them in the nuts and steal their lunch money, but you will never see official Charms or Spells from White Wolf that allow you to break those rules. Bend, maybe. Break, no.
 * It should be noted that the 'no unexalting' rule has found some limited exceptions. It assumes that on a mystical level, the Exalt remains fundamentally human. Green Sun Princes who 'ascend' to full Primordial status with Heresy charms find their Exaltation flitting off to find a new host (not that they need it at that point). Likewise, Exalts who chose to take up a job offer to divinity extended via Greater Sidereal Astrology find their Exaltation moving on once they become Gods. It should be noted that in both of these cases, the exception is allowed because the action of releasing the Exaltation is a choice, and cannot be driven by any supernatural or unnatural compulsion at all else the powers fail to work. The more precise law would have to be "Exaltation cannot be taken away from Exalts, ever".
 * Of course, viewed through another lens the example of becoming a God or becoming a Primordial results in the end of mortality... which looks like death to the Exaltation. In the First Age, the Solar Queen K'tula twisted herself into a fundamentally inhuman cephalopod horror to the point that many of her Solar charms ceased to function properly (because she was no longer remotely human), but her Exaltation lingered because she was still unmistakably alive and mortal (in the sense that her lifespan wasn't infinite).
 * Likewise, there are hardwired rules on just what certain Exalts can learn that other Exalts can't. Sorcery's available to all Exalts, but Dragon-Blooded can only learn first circle (Terrestrial) and only Solars can learn the third circle (Solar). Martial arts are likewise available, but only Sidereal can learn the top level (Sidereal) and Dragon-Blooded are again restricted to Terrestrial arts. Necromancy can only be learned at the highest levels by the Abyssals, and everyone else is capped at once less than what they could learn in Sorcery, meaning Dragon-Bloods can't (usually) learn it at all.
 * One limitation that hasn't been mentioned is that Sorcery cannot alter heavenly bodies. This one is the easiest to get around though: you just need to go to heaven, get the permission of the god whose celestial body you want to move, and fill out the proper paperwork. "Bureaucracy" is a stat in Exalted for a reason.
 * The magic in Shadowrun has similar rules to Exalted: no resurrections, no time travel, and no teleportation. Furthermore, if you do not Awaken naturally, there is (practically) no chance that you ever will. That said, there are still several different flavors of magic-user.
 * Adepts are limited to one type of magic; this can be casting spells (sorcerers), summoning spirits (conjurers), or enhancing the capabilities of their own bodies ("Phys-Ads").
 * Magicians can both cast spells and summon spirits. The exact style and trappings of each magician's talents varies from one practitioner to the next, but the two most common catchall terms are hermetic mages and shamans. It should be noted that, despite the names, there's no arcane/divine magic split; anyone capable of sorcery can learn and use any spell.
 * The indie superpowered-sleuth system Mutant City Blues elevates this to new heights. Sure, there are mutants in the setting, and they can fly, shoot assorted kinds of energy bolts, read minds and even steal each other's powers. All these powers, however, are meticulously catalogued in the so-called Quade Diagram which provides solid insight about what powers can concievably coexist in a person. Some, like supernatural analytical abilities and remote control of electronic devices, are very *close* so that the person posessing one can be routinely assumed to posess another. Others, say, the ability to fly and become invisible, are so far apart in the chart that it is impossible for one man to have both (without breaking the setting and/or having Infinite Experience Points). This diagram, along with more conventional investigative methods, makes the task of solving "Heightened" crimes more of a usual analytical exercise and almost none of the "whoever got more control of The Force" challenge common for less defined supernatural settings.
 * GURPS Thaumatology is a sourcebook dedicated entirely to making up bizarre, yet internally consistent, magic systems. GURPS also has a completely separate system for "psionics," which can be the same exact force as magic, but which are administered in the form of traits specific to a given character, rather than general rules that all magic users have to follow. That's where you go for Wrong-Context Magic.
 * Warhammer 40000 has a very simple magic (all right, 'psychic powers') system allowing various psykers to do different things (mostly attacks or buffs), though they all have a chance of suffering the consequences.
 * Warhammer Fantasy has a more detailed system that has most people drawing on a collective library of spells, though Lizardmen, Chaos, Undead, Orcs and Goblins, High Elves, and Dark Elves all have access to an extra group of spells.
 * In Ars Magica, wizards can do virtually anything, but every spell they case must be formed by combining, basically, constructing a Latin sentence consisting of one of five "techniques" (the verbs, all with the subject "I") and one of ten "forms" (the direct objects). For example, throwing bolts of flame would be "Creo Ignem" ("I create fire"), while making someone forget something would be a "Perdo Mentem" spell ("I destroy the mind"). Every wizard has varying levels of ability with each form and technique which determine how powerful of an effect they can generate (someone with a high score in Creo is good at making things in general; someone with a high score in Mentem is good at working with people's minds in general; someone with high scores in both Creo and Mentem would be extremely good at putting thoughts in other people's heads). Each edition of the game also has a few hard-and-fast rules beyond the verb/object format, such as it being impossible to raise the dead or travel back in time, although whether those things are literally impossible or simply unknown or forbidden to members of the Order of Hermes (the organization player character magi are assumed to belong to) is generally unclear (by design).
 * Mage: The Ascension (which draws from Ars Magica to some extent) and Mage: The Awakening have spheres that work like the "mind" side, and can also be combined (e.g. Correspondence + Mind to mess with someone's head from a distance). Changeling: The Dreaming uses a two-factor system (along the lines of "the mind of a human" or "the mind of another fae"), as does Geist: The Sin Eaters (where a Key determines general dominion and power source and a Manifestation determines what you can do with it).
 * World Tree RPG uses a noun/verb system (7 and 12 of each), but lets several of each be combined in one spell. Eg. a life-extension spell involves "Sustain/Body+Mind+Spirit". And that's the standard "pattern magic", one of several systems the main races know, each with known rules. The trope is played straight in that the rules exist, but subverted in that ultimately the gods control magic and don't do it predictably.

Theatre

 * In Bell Book And Candle, Gillian explains that the effects of spells have to look like coincidences: "I can't bring Niagara Falls down to Grand Central Station, or turn this house into the Taj Mahal. It doesn't work that way."

Video Games

 * The magicka in The Elder Scrolls is an excellent example of this trope. It's never explained in full detail; but it's established as something anyone can practice it in his spare time, but also subject to substantial research by the Dunmer Temple, the Imperial Cult, and the Mages Guild. There are also some very clear rules: to enchant an item, you must know the spell you'll burn in the item, you need a soul gem with an animal soul inside (you can't trap human, bestial or elven souls), and clothes and accessories can hold much more magic than weapons.
 * Funny you should mention enchanting. While it's consistent within each game, the exact mechanics tends to vary wildly throughout the series as a whole.
 * Oblivion showed us that, using Necromancy, it was possible to create a corrupted form of soul gems that are made for capturing Human, Bestial, or Elven souls. And they're more powerful than most animal souls, to boot. They're not available in Morrowind, though, because necromancy is banned in the Morrowind province by the Dunmer Temple.
 * In Morrowind you could trap the soul of a demigod and it is very powerfull indeed. Trying to mess with how magic works also tends to end badly, especialy with Necromancy and Conjuration. Two Oblivion quests also center around the consequences of using magic to travel into your own mind. In one of these quests a divine artifact gets involved and the dreamworld imposes itself on reality inside of the poor wizards tower.
 * Except with the Khajiit, which has resulted in a tangle of lore to reconcile those inconsistencies that puts most fandoms to shame.
 * There are many esoteric rules that are referenced throughout the series but don't appear in actual gameplay. For example, some magic requires "rituals" to perform, such as necromancy or permenant conjuration, which explains why the player can't use them in-game. "Daedric magic" is mentioned as a quick way for eager mages to get their hands on volatile power, though this isn't really elaborated upon.
 * It's hinted at with the Sigil Stones in Oblivion: at higher levels, they're more powerful than Soul Gems, but they can only bestow one spell effect on a weapon or piece of armor. In short, it's a quick-and-dirty way to get a super-enchantment on anything you want, that doesn't even require an Altar.
 * Finally, it appears some, most, or maybe even all rules of magic can be stretched, if not necessarily broken; Ancotar states that permanent invisibilty would "violate the Conservation of Perception," but has created a spell that can keep a whole village invisible for at least a year.
 * In the Aserian Continuity within the Tales (series) (Symphonia, Symphonia: Dawn Of The New World, and Phantasia and its Spin-offs) magic, is magic. But only Elves and Half-Elves can do it. Healing Artes, Light-elemental magic (which are amongst Healing Artes), Angel Skills and Summoning are something else entirely. Symphonia, and Dawn of the New World have a Green Lantern Ring effect with a rare mineral called Aionis that allowed that rule to be broken.
 * Kingdom Hearts plays with this, where certain things will be described and appear consistent... until something comes along that 'breaks the rules'. The authorities on that particular subject will subsequently be as confused as the player, demonstrating the Aesop of “Attempting to apply strict rules to natural phenomena is foolish, as the world is chaotic and wonderful”.
 * Magicka revolves around this. Players have eight basic elements with which to cast spells. Each element has given properties and can be casted directly forward like a projectile, in an area around the caster, or on the caster. There are also opposing elements that will cancel each other out if used while conjuring a spell, or worse. It is very possible to kill yourself with ease or heal the enemy by accident.
 * Though the F.E.A.R. games do not generally provide hand-and-fast rules on how the psychic abilities of Alma work, the abilities of the Point Man and Paxton Fettel are fairly consistent. For example, the Point Man's slo-mo/reflex abilities can only be used for short periods, while Fettel's possession powers will kill anyone he possesses shortly after taking over their bodies.
 * Dragon Age has, among other restrictions, "The Rules" which apply to magic: it's impossible to raise someone from the dead, it's impossible to use magic to travel any faster than "putting one foot in front of the other" (anyone who appears to be teleporting is actually just using an illusion to make them appear to be in one location while they hide and run somewhere else), and entering the Fade physically, while it's technically possible, requires an EXTREME amount of resources (lots of lyrium and Human Sacrifice) and is a VERY bad idea likely to result in divine retribution. In addition, magic requires that mages expend mana (and/or lyrium) or blood. Exactly how other things work (magical healing and the darkspawn taint in particular) sometimes varies.

Webcomics

 * The webcomic Order of the Stick does this with D&D rules (mostly). For an example, there's a strip where Durkon uses Weather Control to attack a group of treants warded against electrical attacks... by generating a thunderclap so loud that it breaks the treants in half. When an angel tells Thor (Durkon's patron god who enabled the spell) that that's not how the spell works (Weather Control cannot determine where the lightning will strike), Thor tells him to be quiet because it was awesome.
 * In Gunnerkrigg Court, Reynardine's possession abilities and contract of ownership with Antimony follow specific and consistent rules. Some of them are given in-comic, but some are only spelled out by the author on the forum.
 * The magical rules in El Goonish Shive are being explained to the audience as the main characters learn them. Every time a new spell is introduced, the readers are told exactly what it is capable of. In addition, it has been explained how characters gain new spells, and how someone can gain access to magic to begin with (continued on the next two pages). It has also been stated that it is impossible to bring the dead back to life, create undead beyond telekinetically using a corpse as a puppet, and to travel through time (though according to the author, time travel is only impossible because Tedd is so Genre Savvy that access to time travel would make him a Boring Invincible Hero).
 * Tales of the Questor has "magic" that is, essentially, Sufficiently Advanced Science--- Magic is actually a natural ability to manipulate an exotic form of energy, can be used via technological means, and generally follows the known laws of physics (Conservation of mass and energy, for example, still apply).
 * A Magical Roommate is fairly flexible, but has some strict rules with its magic system. When it appeared that one of these rules had been broken, Aylia imediatly rushed to figure out how... only to discover Loophole Abuse the cause.
 * In Homestuck the video game sBurb (or sGrub), around which the plot is based, has a series of strict, consistent rules. Its Time Travel rules are also internally consistent.

Web Original

 * Strong Bad, in his shapeshifter e-mail, thinks of the qualms that would accompany shapeshifting. For instance, he can turn into any species of balloon animal, legal tender, has the sound 'dwayne' accompany every transformation, and turning into almost anybody in the world (that is, one-half of the intended person, hence the "almost").
 * In Arcana Magi, Mana is a source of energy akin to electrical energy, with kinetic and potential types. Mana energizes magical items and can be drawn from nature by people with magical powers to cast spells, but cannot be drawn from other people or creatures due to willpower and instinctual resistance. Mana is 100% pure when the object its drawn from is natural, like copper and wood, and slowly but surely the natural object will lose all its Mana when changed into something else, like when copper and electricity is used in a computer. Though in Arcana Magi Zero, different types of magical groups have different ways of drawing mana and casting spells. For instance, Alysia Perez and Megumi Miyazaki are Circular Magi, so all their magical powers come from Magic Circles.
 * Explicitly averted in Tales of MU, where the laws of magic will change if they detect someone trying to figure them out. In-universe, science is a heavily discredited pseudo-, uh, science, much like people who believe in All-Natural Snake Oil in the real world. How, then, does the heavy use of Magitek work, in-universe? Well, that's a good question...
 * There's a difference between craftsmanship and science. You can make a gun without knowing ballistics.
 * That's as may be, but you still can't invent something without understanding the principles that make it work.
 * Pointing out this inconsistency to the author is an excellent way to make her not pay attention to you anymore, however.
 * While any sort of magic (from Hermetic rituals to Native American Ghost Magic to Voodoo to Chinese Necromancy to Holy Miracles to Australian Dreamwalking) is possible in the Global Guardians PBEM Universe, each particular type of magic is internally consistent for that type. You don't find Hermetic mages using Voodoo, or a Christian miracle-worker entering the Dream Time, and so on.
 * The Whateley Universe tries to be consistent about this. Given that the major characters now include a mage who is part Sidhe, a half-demon who has psychic abilities but deals with magic regularly, and an Action Girl with a magic sword, keeping the details consistent across authors must be fairly involved.
 * One story has a character begin to talk about a phenomenon that underlies everything in the universe which is what gives her her powers, only to be told by the other characters that it doesn't exist, or at least, they've seen absolutely no evidence of it. It's a nice thought at how theories are subjective, so when a character explains their own or someone else's powers, they could just be completely wrong yet still come up with an explanation that covers the bases.
 * Part of what helps keep the Whateley Universe canon stories straight is the secret "Whateley Academy Universe Bible" that only canon authors are allowed access to—this lays out every single "rule" for the storyline, canon characters, backstory, etc etc.
 * And, for another one of those 'secrets'...It's not been updated in about three years or so.
 * However it does play looser with acquisition of powers; Phase got his via some sort of virus that was non-contagious and nobody else displays any other form of symptom and Tennyo got hers via what are best described as Magic Screw the Rules I Have Plot Brownies.
 * The Slender Man Mythos is an interesting example; the character is shared between several projects by different groups, and one of the reasons he's so effectively frightful is that the most well-known Slenderblogs and vlogs keep things consistent. There's still wiggle-room for variation without angering the fandom, though: In Marble Hornets, audio and video distortions show up when something bad is about to happen, whereas in Everyman HYBRID, video usually doesn't distort unless Slender Man himself is both in the shot and very close to the camera. In Marble Hornets and Tribe Twelve, being around Slender Man repeatedly tends to make people physically ill; Everyman HYBRID seems to be skipping that one.
 * Actually, the main cast of Everyman HYBRID seem to be coughing up blood after each encounter with Slender Man.
 * Handwaving lack of internal consistency with extreme applications of Bellisario's Maxim is discussed in #3 of Cracked's 6 Common Movie Arguments That Are Always Wrong.
 * Chatoyant College: There are strict rules on what can be achieved with each type of magic.

Western Animation

 * Bending in Avatar: The Last Airbender mostly follows this. Certain characters can use various martial arts derived movements to telekinetically control one of the classical elements. It is possible to utilise this basic mechanic for more esoteric uses.
 * E.g. "Bloodbending" is the act of controlling the water in someone's blood (only possible during a full moon when waterbending is at maximum power). "Metalbending" is the act of controlling the leftover impurities in metal to indirectly bend metal (but only Toph can do that, thanks to her Disability Superpower). Strong Firebenders can generate lightning.
 * The lightning does show something resembling internal inconsistency in the final episodes, though. Supposedly it can only be generated by a firebender who can clear his mind of emotion and distraction—something the internally conflicted Zuko finds himself unable to pull off. However in the end Azula seems to have no difficulties wielding it even while in the middle of emotional turmoil. Either she's just that good (she is a prodigy that bends hotter blue flames), the power-boosting Comet of Doom in the sky had something to do with it, or she has no internal conflict at all about being a psychotic sociopath.
 * So Azula achieved some kind of Reverse Nirvana?
 * Fire produced by firebending doesn't seem to work in the way real-world fire does. I.e. it has concussive force, can burn in the air without fuel etc. This is mostly accepted because whilst not being portrayed realistically it is portrayed consistently. Even Combustion Man's exploding death-ray sparky sparky boom ray is, according to the Nickelodeon Site, something he was born with that allows him to focus his firebending to an extreme level. It also appears that it is that only form of firebending he is capable of. With deadly results...
 * Firebending does break the internal rules in that, unlike the other elements, it can be created out of thin air (other benders can only manipulate existing quantities of their element). Again, it's accepted on the grounds that it's consistent in itself. (Interestingly, Live Action Adaptation The Last Airbender altered this exception, making it much harder to do and essentially enforcing the "must manipulate existing elements" rule.) Note that for the research and physics failing viewers, fire/flame does need tangible fuel (which air most certainly is not) in addition to heat and oxygen in order to exist. Thus, any explanation for fire/flames appearing without an existing fire source or fuel to consume either violates Elemental Baggage or fails physics for the above reason.


 * Of course, the Live Action Adaptation proved why violating this trope isn't necessarily a bad thing, as adhering to it utterly ruined the Fire Nation as a credible threat, and produced a massive Idiot Plot in that the other nations could have easily beaten them just by putting out the dinky little torches they relied on and driving them off when they have nothing left to bend.
 * Flame is plasma and hot gas, so what they are really bending is heat, not matter. Fire bending is explicitly powered by the sun, so it seems they are actually concentrating sunlight and using it to superheat air (or generate an electrical potential). Superheating air quickly would carry a concussive force with it, due to the pressure generated by suddenly increasing the temperature of the air without changing its volume.
 * Even Ty Lee's chi blocking, which appears to come out of nowhere with no explanation, is actually based off of the idea that acupuncture can block chi, and that bending uses chi as well.
 * One interesting aspect to note: According to the Grand Finale,
 * Beast Wars Transformers had the "Transmetal" subline, which was forced on them by virtue of being Merchandise-Driven. Essentially the story goes that they had to destroy a doomsday device in orbit that was threatening them with Death From Above. The resulting "quantum shockwave" changed the bodies of Transformers on both sides, but due to budget (CGI models take a lot more effort to redesign then with traditional animation) only a handful of current characters were redesigned. To try and explain why some changed while others didn't, those who weren't altered were otherwise incapacitated in a repair chamber or something else. It wasn't perfect though, there was still a few inconsistencies with a couple of characters.
 * The Transmetal process was refered to again. A device from the same aliens that sent the "Planet Buster" emitted a paralyzing pulse at the transformers around it. Those who with some form of transmetal in them proved to be immune to its effects. And even later in Beast Machines, a planet-wide virus on Cybertron incapacitated anyone who didn't change and those who did have a transmetal form reverted into their first forms. While it had some nasty side-effects such as memory loss and the inability to transform, that ended up being what saved them from certain capture.
 * Fairly Oddparents has consistent rules for making wishes, except in The Movie there is a magic muffin that allows a certain amount of unrestricted wishing for those trusted with it. The only wish that can't be made is for the magic muffin to taste better (yeah, the muffin is all powerful, but it tastes horrible).
 * Mighty Max established how the portal system works that Portal A leads to Portal B and vice-versa. In order to travel the world they need to move through a series of portals to arrive at their destination, almost like a subway train map. In multiple episodes they show that the portal underneath Max's house leads directly to Skullmaster's cavern, and a portal overhanging a lava waterfall some distance away leads them to Australia, with the nearest portal on foot is 50 miles away.
 * My Little Pony Friendship Is Magic has itself Magics A, B, and C, which are discussed at varying lengths in the show depending on how often it comes up:
 * Magic A is the obvious magic, unicorn magic. Every unicorn has some limited telekinesis for lifting small objects, plus a suite of spells related to their main talent; ergo, a unicorn whose cutie mark signified a particular skill for baking would have spells for getting dough to rise, batter to come together, what have you. Twilight Sparkle is unique in that her talent is the use and understanding of magic itself, so she can potentially learn any spell.
 * Magic B is pegasus magic, mainly cloudwalking and weather control, plus some tactile telekinesis for towing things while in flight.
 * Magic C is the least obvious, earth pony magic. Earth ponies, according to Word of God, have more strength and stamina than unicorns or pegasi of similar physique, and have an innate connection with the earth; so, for example, a farm run by earth ponies would outproduce a farm run by unicorns if all else were equal, simply by virtue of being tended by earth ponies. This also applies to magical crops, such as the Zap Apple.
 * And beyond these types is Magic P, wielded by laughter-made-earth-pony-incarnate Pinkie Pie. She seems to have a completely different set of magical abilities that dabble in all of the above, including abilities that she should not be able to use due to her species type. Basically, the only hard and fast rule for Pinkie Pie is the Rule of Funny, including Breaking the Fourth Wall. Broadly, her ability is to behave like an archetypical classic cartoon character like Bugs Bunny.
 * She also has "Pinkie Sense", an ability to foretell upcoming events by various twitches and feelings in her body. It is precise and consistent enough for the residents of Ponyville to record and use them. It also only works for things in the near future, and has no consistency with any known form of magic at all, much to Twilight's frustration.
 * Fandom being fandom, they use mostly Breaking the Fourth Wall in fanfics, presumably under the assumption that breaking the fourth wall is inherently funny. Fallout Equestria had an interesting variation in that