Sanderson's Second Law
Design the limits first — weaknesses, costs and constraints generate more story than powers ever do.
- Difficulty
- Easy
- Time to result
- ~weeks to results
- Steps
- 6
- Confidence
- 92%
Ferriss reads the second law as 'weaknesses limits and costs are more interesting than powers,' and immediately names it the power of constraints — the one he most latched on to. Sanderson's worked example is Superman, a character with essentially unbounded capability who is nevertheless interesting only through his boundaries. He identifies three: an external constraint, kryptonite; an internal one, the moral code Superman imposes on himself and might break; and a relational one, the people he loves, whose vulnerability limits what he can do. Sanderson's claim is that the three great Superman stories all sit on one of those, and none of them centre on what he can do. The input is any capability you have designed. The mechanism is deliberately inverting the design order: instead of listing what the power enables, you enumerate what it costs, what it cannot touch, and who it endangers, and you build scenes on those. The output is renewable conflict, because limits are what produce choices and choices are what produce story. He extends the same reasoning to the One Ring, which offers short-term gain for long-term detriment, and to his own magic systems, where combat becomes a puzzle box precisely because the metals do only specific things.
Origin
Sanderson formulated his three laws after repeatedly breaking his own magic systems and needing a rule of thumb to stop it happening again. The second emerged as he examined the powers he kept adding to books and noticed that every genuinely good scene was built on what a character could not do.
Core principles
- 01Weaknesses, limits and costs are more interesting than powers.
- 02Conflict cannot exist where capability is unbounded, so every unit of power you add must buy a unit of constraint.
- 03Limits come in three forms — external kryptonite, internal moral code, and attachment to people — and all three generate story.
- 04The interesting question about any capable character is never what they can do but what they cannot.
- 05A cost paid for short-term gain against long-term detriment is the most reusable engine in fiction.
- 06The same logic transfers outside fiction: constrained systems are more legible and more engaging than unconstrained ones.
How to run it
- 1
Write the power in one sentence
State plainly what the ability, advantage or system does. Keep it short — the point is to have a fixed object to constrain, not to elaborate it.
Pro tip If the sentence needs qualifiers, you have already got two powers, not one.
- 2
Add an external limit
Introduce something in the world that simply switches the power off or blunts it, independent of the character's choices. Kryptonite is the archetype.
Pro tip External limits are the cheapest way to restore doubt in a scene without rewriting the character.
Watch out If the external limit is always available to the villain, it stops being a limit and becomes the plot.
- 3
Add a self-imposed limit
Give the character a code they could break and choose not to. Sanderson: the best stories happen 'because of his moral code, will he break or not.'
Pro tip This is the only limit that produces genuine internal conflict, so it does the heaviest narrative lifting.
Watch out A code with no cost to keeping it is decoration, not a constraint.
- 4
Add a relational limit
Attach the character to people whose safety narrows their options. Sanderson counts loved ones explicitly as a kind of limitation.
Pro tip Relational limits let you threaten a character who cannot personally be threatened.
- 5
Price every use
Define what using the power costs. The One Ring model — short-term gain, long-term detriment — makes each use a decision rather than a reflex.
Pro tip Costs that accumulate across a book create a second progress counter for free.
Watch out Free powers get used constantly and lose all dramatic weight by the midpoint.
- 6
Map scenes onto limits
Go through your outline and label which of the limits each major scene presses on. Unlabelled scenes are the ones that will read as filler.
Pro tip Rotating through the three limits gives a book variety without adding new capabilities.
Watch out Scenes that only demonstrate the power are the first thing beta readers report skimming.
In the wild
Sanderson argues that a character who can do essentially anything is only interesting through what he cannot. Superman cannot get Lois to fall in love with him, cannot always protect everybody, cannot violate his own code, and can do nothing when kryptonite is present. Those four impossibilities, he says, are where all the real Superman stories live — none of them centre on the powers themselves.
→ A character with no theoretical vulnerability sustains decades of stories because his constraints, not his abilities, are the material.
Because Mistborn's metals each do one specific thing and nothing else, Sanderson's fight scenes become logic problems. A character drops a coin and pushes off it to launch upward, or throws and pushes it to fire it across a room and get knocked backward in turn. Each fight is a question of how to get into position for the one thing the constrained system permits.
→ Tight limits turned action scenes into engaging puzzles that Sanderson describes as fun to write every time.
Common mistakes
Adding powers to raise stakes
The instinct when a story sags is to give the protagonist or the antagonist something new. This raises spectacle and lowers tension, because the audience loses track of what is genuinely at risk. Add limits instead.
Treating internal logic as optional because the premise is absurd
Sanderson notes Superman's sunlight-powers make no external sense at all, and that this is fine. What is not fine is inconsistency — audiences forgive an implausible rule and never forgive a rule that changes when convenient.
Giving a character limits they never have to face
A code that is never tested, a loved one never endangered, a kryptonite never present — these are limits on paper only. If your outline never presses them, they contribute nothing.
Is it for you?
Best for
Anyone designing a character, ability or system where the audience must keep believing the outcome is in doubt.
Not ideal for
Deliberate power-fantasy or comfort formats where the audience's whole reward is watching an unstoppable protagonist steamroll opposition.
From the transcript
“number two weaknesses limits and costs are more interesting than Powers”
“Superman is interesting because of what he can't do Superman as a character is interesting because he has a moral code which is you know…”
“all of them don't Center on what his powers are centers on what he can't do”
From the episode
#794: Brandon Sanderson on Building a Fiction Empire, Creating $40M+ Kickstarter Campaigns, Unbreakable Habits, The Art of World-Building, and The Science of Magic Systems