Inversion
Charlie Munger
Instead of asking how to succeed, ask: what would guarantee failure? Then avoid those.
Second-Order Thinking
Howard Marks
And then what? Trace consequences two and three steps past the obvious first effect.
First-Principles Thinking
Aristotle / Musk
Strip the problem to physics-level truths. Rebuild from primitives, not analogies.
Regret Minimization Framework
Jeff Bezos
Project yourself to 80. Which choice will you regret not having tried?
Two-Way vs. One-Way Doors
Jeff Bezos
Reversible decisions deserve speed. Irreversible ones deserve patience and process.
10/10/10 Rule
Suzy Welch
How will you feel about this in 10 minutes? 10 months? 10 years?
Pre-Mortem
Gary Klein
Imagine the decision failed catastrophically. Walk backward: what killed it?
Opportunity Cost
Economics
The real cost of a "yes" is every "no" it forces. What are you giving up?
Sunk Cost Fallacy
Behavioral Economics
Past investment is gone. Decide forward only on future value, not past commitment.
Circle of Competence
Warren Buffett
Know the perimeter of what you actually understand. Decisions inside it are cheap; outside, expensive.
Margin of Safety
Benjamin Graham
Build buffer for the case where you're wrong. Don't price assumptions to perfection.
Expected Value
Probability Theory
Multiply outcomes by probabilities. Choose the bet with the best long-run math, not the best feeling.
Probabilistic Thinking
Annie Duke
Stop asking "will it work?" Start asking "what are the odds?" and act on the distribution.
Base Rates
Tversky & Kahneman
What's the historical batting average for decisions like this one? Anchor there before the story.
Bayesian Updating
Thomas Bayes
Start with a prior. Update incrementally as evidence arrives. Hold no belief with 100% confidence.
Occam's Razor
William of Ockham
Among competing explanations, the one needing the fewest assumptions usually wins.
Hanlon's Razor
Robert Hanlon
Never attribute to malice what is adequately explained by incompetence or oversight.
Chesterton's Fence
G.K. Chesterton
Before removing something, understand why it was put there. Don't reform what you can't first justify.
Pareto Principle (80/20)
Vilfredo Pareto
Roughly 80% of effect comes from 20% of causes. Find that 20% before anything else.
Eisenhower Matrix
Dwight Eisenhower
Sort by urgent/important. Do the important-not-urgent before it becomes the urgent crisis.
The 70% Rule
Jeff Bezos
Decide when you have ~70% of the info. Waiting for 90% is usually slower than course-correcting.
Hell Yeah or No
Derek Sivers
If it's not a "hell yeah," it's a no. The middle is where commitment quietly drains out of life.
Loss Aversion
Kahneman & Tversky
Losses feel ~2x stronger than equivalent gains. Are you saying no out of fear, not strategy?
Survivorship Bias
Abraham Wald
You're studying the winners. The full picture also requires the silent losers you'll never hear from.
Confirmation Bias
Psychology
You weigh evidence that fits your hypothesis more heavily. Actively hunt for what would prove you wrong.
Anchoring Bias
Kahneman & Tversky
The first number or framing sets the reference point. Reset to absolutes before judging "good" or "bad."
Availability Heuristic
Kahneman & Tversky
Vivid recent examples feel more probable than they are. Are you over-weighting one memorable story?
Status Quo Bias
Psychology
We default to "no change" even when change is the better expected-value play. The cost of inaction is real.
Steelmanning
Rationality
Build the strongest possible version of the opposing view before deciding. Refute that, not a strawman.
The Veil of Ignorance
John Rawls
Would you choose this if you didn't know which role you'd play in the outcome? A fairness stress-test.
Five Whys
Toyota / Taiichi Ohno
Ask "why" five times in succession to drill from the surface symptom to the actual root cause.
Falsifiability
Karl Popper
A belief you can't imagine ever being wrong is not a conclusion — it's an identity. State the conditions that would change your mind.
Antifragility
Nassim Taleb
Choose options that benefit from volatility and stress, not just survive it. Optionality compounds.
Lindy Effect
Nassim Taleb
For ideas and non-perishables, the longer it's been around, the longer it'll likely stay. Bet with time.
Map vs. Territory
Alfred Korzybski
Your model is a simplification. Watch where the model breaks against the actual terrain.
Goodhart's Law
Charles Goodhart
When a measure becomes the target, it stops being a good measure. Watch what your metric is quietly distorting.
Parkinson's Law
C. Northcote Parkinson
Work expands to fill the time given. Shrink the timebox and the decision gets sharper.
Hofstadter's Law
Douglas Hofstadter
It always takes longer than you expect, even when you account for Hofstadter's Law. Pad the timeline.
Game Theory
John Nash
Other players are optimizing too. What's their best response to your move? Reason about the equilibrium.
Schelling Point
Thomas Schelling
Without communication, what would each party naturally converge on? Use focal points to coordinate.
Counterfactual Thinking
Philosophy
What would have happened anyway, without your action? Subtract the noise to measure your real contribution.
The Dichotomy of Control
Epictetus / Stoicism
Separate what's in your control from what isn't. Spend zero effort outside the line.
Compounding
Mathematics
Small advantages, repeated, beat large advantages, abandoned. What is the version of this decision that compounds?
Optionality
Nassim Taleb
Prefer choices that keep future doors open at low cost. Pay small to preserve big upside.
Decision Journal
Annie Duke / Shane Parrish
Write down what you decided, why, what you expected. Review later. Separates good decisions from lucky outcomes.
Worst-Case / Best-Case / Likely
Scenario Planning
Spell out all three. Can you live with the worst case? If yes, the upside is mostly free.
Reversion to the Mean
Francis Galton
Extreme results — good or bad — tend to drift back toward average. Don't extrapolate a hot streak.
Two-System Thinking
Daniel Kahneman
System 1 is fast and emotional. System 2 is slow and deliberate. Big decisions deserve System 2; small ones don't need it.
Doorman Fallacy
Rory Sutherland
Don't reduce a role to its narrowest function. The doorman opens the door; he also signals luxury, safety, and ceremony.
Scout Mindset
Julia Galef
Be a scout, not a soldier. Goal isn't to defend a position — it's to see the terrain accurately.
Pascal's Wager (Asymmetric Risk)
Blaise Pascal
When downside is catastrophic and upside is moderate (or vice versa), don't use expected value alone — weigh the asymmetry.
Black Swan Defense
Nassim Taleb
Plan for the unmodeled rare event. The most damaging surprises come from outside the distribution you considered.
ICE / RICE Scoring
Product Management
Score by Impact × Confidence × Ease (and Reach). Forces you to commit to numbers, not vibes.
The Pareto Frontier
Economics
Among multiple goals, find options that can't be improved on one axis without sacrificing another. Stop optimizing inside dominated choices.
Skin in the Game
Nassim Taleb
Trust forecasts only from people who bear the downside if they're wrong. Whose advice survives if it backfires on them too?
Via Negativa
Nassim Taleb
Improvement often comes from removal, not addition. What should you stop doing instead of layering on something new?
Barbell Strategy
Nassim Taleb
Combine extreme safety with extreme risk; avoid the mediocre middle. Hedge the floor so you can swing for the ceiling.
Iatrogenics
Nassim Taleb
Harm caused by the intervention itself. Could the cure here damage more than the disease you're treating?
Planning Fallacy
Kahneman & Tversky
You underestimate cost and duration of your own plans even when you know about this bias. Use outside-view base rates, not inside-view optimism.
Fundamental Attribution Error
Lee Ross
You explain others' behavior by character but yours by circumstance. Are you reading the situation, or just reading the person?
Dunning-Kruger Effect
Dunning & Kruger
Low competence pairs with high confidence; expertise breeds doubt. Is your certainty a signal of mastery — or the absence of it?
Hindsight Bias
Baruch Fischhoff
"I knew it all along" rewrites the past so the outcome looks inevitable. Distorts the lessons you draw from your last big decision.
Endowment / IKEA Effect
Thaler / Norton, Mochon & Ariely
You overvalue what you already own and what you personally built. Would you actively choose this option today if you didn't already hold it?
Hyperbolic Discounting
Behavioral Economics
You over-weight near-term reward relative to long-term payoff. Why "future you" keeps getting betrayed by "present you."
Mimetic Desire
René Girard
We want what others want, not what we actually want. Strip the social signal: would you still want this if no one knew you chose it?
Tragedy of the Commons
Garrett Hardin
Individually rational behavior produces collectively destructive results. If everyone in your position defected the same way, what breaks?
Bike-Shedding (Law of Triviality)
C. Northcote Parkinson
Groups burn disproportionate time on trivial details they can easily opine on. Are you debating the easy 5% to avoid the hard 95%?
OODA Loop
John Boyd
Observe → Orient → Decide → Act, then loop faster than the environment changes. When iteration speed beats one-shot accuracy.
Cynefin Framework
Dave Snowden
Diagnose the domain — simple, complicated, complex, chaotic — before picking a method. Most bad decisions are a domain mismatch.
Kelly Criterion
John Kelly
Even a positive-EV bet ruins you at the wrong stake size. Size the bet to the edge and the odds, not to your conviction.
Flywheel Effect
Jim Collins
Many small pushes in one direction compound into momentum. Which version of this decision builds a flywheel vs. starts from rest each time?
Hedgehog Concept
Jim Collins
Focus where what you love, what you're best at, and what pays intersect. A filter for opportunity-rich, attention-poor decisions.
Cobra Effect
Horst Siebert
When the fix creates the very problem it was meant to solve. What perverse incentive does this decision quietly plant?
Path Dependence
Paul David
Today's options are constrained by yesterday's choices. Which doors does this decision close on your future self?