Think in models,
not in guesses.
A clear, honest encyclopedia of the mental models, cognitive biases and ways of reasoning that make better decisions — each one defined, worked through with a real example, and cross-linked to what it connects to.
A reference built for clearer decisions
Defined, not hand-waved
Every entry opens with a one-line definition and a plain-language explainer — no jargon, no filler. You leave knowing exactly what the idea is and when to reach for it.
Worked with real examples
A concrete worked example on every page, plus the model's limits and failure modes — because a thinking tool you can't see misfire is a tool you'll misuse.
Cross-linked, like real thinking
Models link to the biases they counter and the explainers they compose. Follow one idea to the next and build a connected map instead of a list of loose tips.
Mental models
Inversion
Solve a problem by asking how to guarantee the opposite of what you want — then avoid that.
Read the entry → ModelThe Map Is Not the Territory
Every model is a simplification of reality — useful, but never the thing itself.
Read the entry → ModelMargin of Safety
Build in a buffer so that being wrong — and you will be — doesn't ruin you.
Read the entry → ModelCompounding
Small gains that build on themselves grow slowly, then astonishingly fast.
Read the entry → ModelFirst-Principles Thinking
Break a problem down to what you know is true, then reason up from there.
Read the entry → ModelSecond-Order Thinking
Ask "and then what?" — trace the consequences of your consequences before you act.
Read the entry →Cognitive biases
Confirmation Bias
We seek, favour and remember evidence that fits what we already believe.
Read the entry → BiasSunk-Cost Fallacy
Continuing something because of what you've already spent, not what it's now worth.
Read the entry → BiasAnchoring
The first number you see quietly drags every later estimate towards it.
Read the entry → BiasAvailability Heuristic
We judge how likely something is by how easily examples come to mind.
Read the entry → BiasDunning–Kruger Effect
The less skilled we are at something, the more we tend to overrate our skill at it.
Read the entry → BiasSurvivorship Bias
Judging from the winners you can see, while the losers who'd change the story are invisible.
Read the entry →How to think
How to Think About Risk
Separate the probability of an outcome from the size of its consequences — and respect ruin.
Read the entry → How to thinkHow to Think About Decisions Under Uncertainty
Judge decisions by the quality of the process, not the outcome — and think in probabilities, not certainties.
Read the entry → How to thinkHow to Think About Incentives
To predict behaviour, look at what people are rewarded for — not what they say.
Read the entry →Where each idea comes from
Every model and bias sits in the field it grew out of. Start from a discipline and follow the connections outward.
From a single idea to a way of thinking
Look one up
Search for the model, bias or question on your mind — from opportunity cost to the sunk-cost fallacy to how to think about risk. Each has its own clear entry.
See it work — and fail
Read the definition, a worked example, and the honest part most references skip: exactly when the idea misleads you and how to avoid the trap.
Follow the connections
Every entry links to the ideas it relates to, contrasts with or is built from. Follow them and a scattered toolkit becomes a connected way of reasoning.
Build the toolkit, deliberately.
Start with one model today. Come back for the next. A better way of thinking is built one connected idea at a time.
Explore the encyclopedia →