"Limitations are more important than powers."
"Expand on what you already have before you add something new."
Brandon Sanderson's Laws of Magic are a set of rules of fiction meant to help writers have good magic, but also to integrate that magic in worldbuilding.
Sanderson's First Law
The First Law
claims that the more clearly defined and understandable a magic system is, the more an author can utilize it in their plot. Simplified, it can be interpreted as: "The better the reader understands something, the more that said thing can be used to resolve conflict."
The purpose of this Law is to help authors avoid creating Ass Pulls and/or Deus Ex Machinas, which can easily break viewers' Willing Suspension of Disbelief—if the rules for Magic A are clearly defined and consistently obeyed throughout the work, then it is much easier for the audience to accept it when the characters use Magic A to solve a problem. Thus, the Law advises authors to create and explain basic rules for their magic systems so that the readers not only understand what the magic does, but also how it works and why.
Such rules can manifest as either "Hard magic" or "Soft magic" systems. An example of the former would be The Dresden Files by Jim Butcher, where magic is very clearly laid out at a "nuts and bolts" level—as if it were a hard science—with set limits and explanations as to how it works, without ever going outside of those established boundaries. With soft magic systems, on the other hand, the rules can be amorphous so long as the reader can understand just as well whether or not the magic is applicable to a given situation. For instance, Dragon Ball never truly explains how Ki Manipulation and training to improve one's power really works, but it does follow a consistent set of rules as to who can do what and why they can do it—all of which is shown to the viewer.
In accordance with the above, magic which is either not explained or has only recently been introduced to the reader should not be used to solve problems; only to create them—in such cases, the protagonists now have to solve the problem using more mundane methods. This formula is good for building worlds that feel mysterious and dangerous, such as the worlds of Middle-Earth, Narnia, and Westeros.
Sanderson demonstrates the first aspect in his own rigorously detailed magic systems, most notably in his Mistborn books. Throughout the Mistborn series, only half of the magic system had been explained in detail, but the readers were able to correctly determine the nature and abilities of the other half based on the information that Sanderson had provided.
Sanderson's Second Law
The Second Law says that "Limitations are more important than Powers". This means that powers don't make a character interesting; what matters is what they can't do. Sanderson uses Superman as an example, pointing out that Superman has flight, super-strength, laser vision, and plenty of other abilities. But what makes Superman interesting are his moral code and his weakness to kryptonite.
The purpose of this law is to help authors avoid creating a No Permanence, No Stakes situation. Simply put: if the audience does not know what your characters' limitations and weaknesses are, then the story will lack tension because there is no reliable way of telling who has the upper hand in a fight—it's hard to get a sense of desperation and empathize with the heroes if, for all the audience knows, said heroes might be packing a superpower which can easily plow through any obstacle they encounter, at seemingly no personal expense.
Sanderson subdivides these flaws into Limitations, Weaknesses, and Costs. Limitations are those things that the magic can't do (such as "Superman can't see through lead" or "magic cannot unmake something"). Weaknesses are things the magic is vulnerable to or ways that using it makes you vulnerable (such as "kryptonite takes away Superman's powers" or "while you're wearing the One Ring, the Ringwraiths can see you"). Costs are ways in which using the magic has a price, e.g. "a given location in the world only has a finite amount of mana".
Sanderson's Third Law
The Third Law tells writers to expand what they already have before they add something new. In other words: it is better to prioritize quality over quantity, or depth over breadth.
The purpose of this law is to help authors create worlds that, while perhaps small in scale, manage to feel 'alive,' with characters and systems which become even more compelling the more that readers delve into them. This is in contrast to vast worlds with dozens of barely explored concepts (and, potentially, a large number of overlooked Plot Holes). Effectively therefore, this Law is a partial rejection of Measuring the Marigolds.
To do this, there are three directions a writer can take: Extrapolate, Interconnect, or Streamline.
Extrapolating is when you ask the "What happens when...?" question. Sanderson gives examples like: “What happens when a wizard converts to Christianity?” “What happens to warfare when magic can create food out of thin air, enabling much more mobile armies?” “What happens to gender dynamics if magic causes all of the men who use it to go insane?”
Interconnecting means that rather than keep all the different kinds of magic as separate "isn't that cool" abilities, a writer should think about how different powers can be part of both the worldbuilding and the story's core themes.
Streamlining is when you look at all your magic and think, "Where can I combine these?" Again, this can be done with the powers themselves, or you can take one aspect of magic and have different cultures understand it in different ways.
Sanderson's Zeroeth Law
In his online lectures, Sanderson has capped his laws off with the Zeroeth one: Always err on the side of what is awesome. On the surface, it seems like an endorsement of both Bellisario's Maxim and the Rule of Cool, but it really isn't. Rather, the Zeroeth Law is a reminder that magic systems—and world-building in general—are only a means to an end: creating a good story. And good stories usually come about when the author finds a particular set of ideas which are captivating to both them and their audience. Thus, it is best to start with what would make for an engaging story and work backward from there; constructing a world in which that awesome thing would naturally fit.
An excellent example of this is Shardblades from The Stormlight Archive. In his interviews, Sanderson has discussed how a core inspiration for the Shardblades was taking the massively oversized swords from anime and fantasy art, and asking "How could you make a weapon that big actually practical to use? And what kind of enemy would require something like that to fight?"
Sub-Trope of "Magic A" Is "Magic A" and The Laws of Magic.
Examples:
Anime & Manga
- JoJo's Bizarre Adventure: Each Stand has only one power and no more—often, severely limited in scope as well. It's up to the creativity of the user to mold that power into something useful while still playing within the rules of said power.
- Magical Girl Lyrical Nanoha StrikerS: The Nanoha series has always been fairly consequential about how its magic works, but it really comes to shine during the final battle of StrikerS, when Nanoha utterly destroys Quattro's schemes by combining two basic abilities the audience already observed her use many times: Area Search, which finds whatever Nanoha wants to locate, and Divine Buster, which blasts anything dumb enough to be in the White Devil's way into oblivion.
Web Video
- Mother's Basement: While describing The Strongest Sage with the Weakest Crest as part of his "Hottest Trash Anime of Winter 2022" episode, he contrasts its soft, Ass Pull-prone magic system with the rules-based system from Brandon Sanderson's novels, in particular citing the Second Law, that limitations are more interesting than the powers.
