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Sanderson’s Third Law of Magic

We’re celebrating the release of Steelheart, my new novel! It’s out this week. If you missed yesterday’s post, you can read up on the book here, listen to the first five chapters of the audiobook here, and watch the trailer here.

Please consider going to your retailer of choice and looking at the novel. I’m extremely proud of it. Also, play along in the Steelhunt!

As part of the celebration, I present to you Sanderson’s Third Law.


At long last, it’s time for me to continue my series on how I develop magic systems for my books. If you haven’t read the first two pieces in this sequence, check out Sanderson’s First Law and Sanderson’s Second Law.

When I speak about these laws, I often make some wisecrack about how humble I am. (I named them all after myself, you see.) However, the reason I named them as I did is not because I view them as rules that everyone must follow in developing their magic systems. Instead, these are observations about what have made my own magic systems better—in the way I like to design them. Therefore, they are laws that I try to follow in my writing.

At times, I’ve broken these laws—indeed, I’ve figured them out over time by noticing places in my fiction where the magic system doesn’t work as well as I’d like. You could say breaking the laws is what taught me about them in the first place.

Remember that in writing, nothing is absolute. I don’t read a book and think to myself, “I wonder how well this magic system follows Sanderson’s Laws!” When I read, I’m there to enjoy the story. However, when I analyze why something works or doesn’t work—particularly in a book I’m working on—often these concepts will come into play.
Anyway, without further rambling, the third law is as follows: Expand what you already have before you add something new.


There are a lot of potential worldbuilding pitfalls a fantasy and science fiction writer can stumble into. One of these is making your story boring by overburdening it with too much expository worldbuilding. This, in turn, is often a symptom of a writer who spent years and years practicing worldbuilding—but not much practicing the actual craft of writing.

Because of this, I sometimes warn about what we call “worldbuilder’s disease,” which is a little like warning a bodybuilder friend not to skip leg day. Practicing worldbuilding is important, but to have a well-balanced story, a potential writer will also need to practice prose, characterization, and plotting. You’re not a pianist if you only learn to play one song, even if you can play it really well—instead, you’re a party trick.

(Now, I’ll add the caveat that worldbuilder’s disease is only a problem for writers who want to make a professional living writing books. If your goal is to have fun worldbuilding, and the writing of a book is something secondary to that, then there’s nothing at all wrong with focusing your time on your setting. Do what you enjoy.)

Anyway, because I talk a lot about the dangers of over-worldbuilding, you might think that I’m against it entirely. Not at all—I like stories with massive worldbuilding, intricate worlds, and clever use of magic.

That’s where this law comes in.

Often, the best storytelling happens when a thoughtful writer changes one or two things about what we know, then extrapolates purposefully through all of the ramifications of that change. A brilliant magic system for a book is less often one with a thousand different powers and abilities—and is more often a magic system with relatively few powers that the author has considered in depth.

This is something I’ve come to realize over a long time. I often fall into the trap of thinking that “Bigger is better, and more is more awesome.” Films have this trouble all the time. How often has a sequel been ruined by this mentality? (An example comes from the Spiderman franchise of last decade, where the third film was widely panned for trying to cram too many villains into the space—when one very dangerous and compelling villain often makes a better story.)

In epic fantasy books, it’s not the number of powers that creates immersive and memorable worldbuilding—it’s not even the powers themselves. It’s how well they are ingrained into the society, culture, ecology, economics, and everyday lives of the people in the stories.

In short, this law challenges me to create deep worldbuilding instead of just wide worldbuilding.

I’ll talk about expanding a magic in three directions I’ve found useful.


In developing your magic, your job as a writer is to look at how the changes you’ve made will affect the world as a whole. Keep this within reason, depending on your story’s goals and lengths. Epic fantasy has space for looking at history and economics, while a tight urban fantasy may instead want to look at one specific factor—such as how synthetic blood might affect vampire culture.

Extrapolating, to me, is about asking the “what happens when” questions. “What happens when a wizard converts to Christianity?” “What happens to warfare when a 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?”

Often, both in my own books and the books I read, if the worldbuilding comes out in a jumbled mess it’s because the writer is trying to shove far too many powers into a tight space. Instead, picking several of those powers and showing the problems they create in the lives of the different characters might make more sense. Instead of giving every character a new power, can you have different takes on the same powers, used in different ways?


Everything I’m talking about can be taken too far, and that goes for this law as well. In some of my own works, I’ve enjoyed having a large list of powers to draw from—it has helped me create a more unique experience for my storytelling. Some of my favorite series, such as the Wheel of Time and Discworld, involve a massive amount of worldbuilding and a story world where tons upon tons of things can happen. We want a fantasy epic to be immersive and evoke an entire world full of dozens, if not hundreds, of different cultures and peoples.

The second piece of advice I have here, then, is a suggestion that you tie your powers, cultures, and themes together in your story. If I am going to have multiple magic systems—or multiple powers available to a single character—I ask myself how I can connect these powers so they work together, rather than feeling like separate “isn’t that cool” abilities given to a character.

I try to avoid using too many examples from my books, as these essays aren’t intended to be me bragging about what I’ve done well. At the same time, I do think occasionally I hit the target—and when it comes to interconnection, the Mistborn magic system very much came together.

When developing the system, I knew I wanted a wide variety of powers. The first attempts at it had some very odd powers that didn’t fit with the others. In designing the magic, I realized that if I themed all of the abilities toward things a group of thieves would want to be able to do, I could name each power after a role in a thieving crew. This cohesion formed the core of what brought the magic system together.

(Further pieces of interconnection included designing the table at the back, with different categories of powers—though I certainly don’t think this is something you need to do for every magic. It lent strength to the sub-theme in Mistborn of a society on the cusp of industrial revolution.)

Tying your powers together thematically, and asking yourself how they play into the themes of your novel, will very much help you worldbuild and expand, instead of adding. You’ll end up with a magic system that feels like an important part of your book, and less like it includes “everything and the kitchen sink.” (A problem that was common to many early magic systems, like those of early superhero comics.)

Do note that this works very well for other types of worldbuilding as well. Asking yourself how your economy interconnects with the religions of your world can help you develop both in a more interesting and way—and then asking how those interconnect with your theme, and the challenges of your characters, will create a much stronger book as a whole.


The third and final suggestion in this area is to look over your cultures, magics, and even characters and ask yourself, “Where can I combine these?”

This is particularly applicable when it comes to magic systems, and characters with powers. I’ve started asking myself more and more when developing a culture, “How can I take some already-existent piece of this world, and show a new culture’s reaction to it?” Instead of developing a brand-new religion, I ask myself if a schism in an already existent religion would not work better. Instead of adding a new character with a new power, I ask if this character can approach one of the already-existent powers in a new and interesting way.

In another example, my experience has been that if you’re going to visit ten kingdoms in your novel, your first instinct might be to create ten new quirky magic systems to distinguish them. Instead, you might want to consider creating one distinctive thing magic does in this world, then have each culture use it in a different way. A simple magic—such as some people being able to change their skin color at will—could spawn religions, influence social mores, provoke wars, play havoc with caste systems, create new kinds of jobs.

Streamlining in this way helps with a number of things. It keeps down complexity creep in your stories—something that is not as big a problem in book one as it becomes in book seven. It helps your narrative be more tight, and it has (with me) forced me to reach deeper into character design. Instead of a character being “look at this wacky power” it has become, more and more, “let’s have someone who looks at the world differently explore their problems with society and the setting.”

Harriet tells a story about this regarding Robert Jordan, who had originally intended his Wheel of Time series to be about four young men who are thrown into something above their heads. Partway into the first book, Harriet pointed out to him that one of the young men was never really doing anything. Robert Jordan kept saying that he’d be important in later books.

Harriet’s wise advice: “If the first one isn’t good, there won’t be any later books.” Robert Jordan cut the character and gave his parts to the other characters, and in so doing made them all increase in depth.

Now, there are ways you can take this one way too far. One example is giving all of the growth, interesting new powers, and adventures to one person—essentially ending up with a single hero who has been through way too much and had way too many experiences. It can strain plausibility. (Though, then again, some series are built on just this idea.)

A larger problem of streamlining can be developing each culture of your world to be identical, except for one little defining trait—such as how they look at religion. That’s streamlining way too far.

However, this rule of thumb has helped me a great deal over the years.


Expand, Don’t Add.

It can be tough to decide when to apply this idea. For me, Law Three is a constant balancing act—much like the balancing act between showing and giving exposition. Exposition is important; it can move the narrative forward and can establish setting elements quickly. Taking time to show a concept, instead of explain it, often requires a lot more words—though it usually creates a more powerful scene.

Getting the balance right takes effort, and the “right” balance will be different for every story. The same goes for pushing your worldbuilding depth, as opposed to adding more breadth to it. When do you spend time making an existing culture more deep to add to the strength of the storytelling, and when do you introduce a new culture to improve the sense of wonder and scope of a book?

I will tell you this, though. When I stopped thinking of the Stormlight Archive along the lines of “I want to add more awesome magics!” and instead started thinking, “What are the common themes to the magics, and how can I interconnect and consolidate those themes?” my worldbuilding got stronger.

It’s okay to go big. It’s okay to go epic.

But be sure to go deep as well.


|   Castellano