Mental Model Inventory
Mar 19, 2025
Good decisions aren't about having more information—they're about seeing clearly. These mental models help cut through complexity, reduce bias, and make better choices.
01. First Principles Thinking
Break problems down to their most basic elements and build up from there.
Used by: Aristotle, physicists
Example: Instead of assuming existing car battery costs, Tesla rethought material sourcing to lower prices.
02. Bayesian Thinking
Update beliefs based on new evidence rather than sticking to initial assumptions.
Used in: AI, medicine, decision-making under uncertainty
Example: If a test is 95% accurate but the base rate of the disease is low, the actual chance of having it may still be low.
03. Expected Value
Weigh potential outcomes by their probability and impact rather than relying on gut instinct.
Used in: Investing, business strategy, poker
Example: If a decision has a 10% chance of a 100x return, it may still be worth pursuing.
04. Inversion (Thinking Backwards)
Instead of asking "How do I succeed?" ask "How do I fail?" and avoid those mistakes.
Used by: Charlie Munger, Stoic philosophers
Example: If you want to live a good life, avoid regret—don't ignore health, relationships, or lifelong learning.
05. Occam's Razor
The simplest explanation is usually the best.
Used in: Science, troubleshooting, decision-making
Example: If you hear hoofbeats, think horses, not zebras (unless you're in Africa).
06. Hanlon's Razor
Never attribute to malice what can be explained by incompetence or ignorance.
Used in: Conflict resolution, leadership, interpreting behavior
Example: That rude email probably wasn't personal—the sender might just be stressed.
07. Second-Order Thinking
Always consider the longer-term consequences beyond the immediate result.
Used in: Policy-making, investing, product strategy
Example: Rent control helps tenants short-term but may reduce housing supply long-term.
08. Compounding Effects
Small, consistent actions over time create massive long-term results.
Used in: Finance, habits, learning
Example: Reading 10 pages a day equals 12+ books a year.
09. Circle of Competence
Know what you know, and don't pretend expertise where you have none.
Popularized by: Warren Buffett
Example: If you don't understand cryptocurrency, don't invest in it.
10. The 80/20 Rule (Pareto Principle)
80% of results come from 20% of causes—focus on the highest-leverage activities.
Used in: Business, productivity, investing
Example: 20% of customers often drive 80% of revenue.
11. The Red Queen Effect
To stay ahead, you must keep improving just to maintain your position.
Used in: Business competition, evolution, career growth
Example: If you're not learning new skills, you're falling behind.
12. Game Theory
Some games are about beating the opponent, others are about growing the pie.
Used in: Negotiations, diplomacy, business strategy
Example: A company's success isn't about crushing competition but creating new value.