First Principles
Break problems down to their fundamental truths. Rebuild from there. Aristotle's method, used by engineers and founders.
Mental Models
Frameworks for thinking clearly across disciplines.
Second-Order Thinking
"And then what?" Most people stop at the first consequence. The best thinkers trace the ripple effects.
Inversion
Instead of asking how to succeed, ask: how would I guarantee failure? Then avoid those things. Charlie Munger's favorite.
The Map Is Not the Territory
Every model simplifies reality. The skill is knowing which simplifications are dangerous — and which are useful.
Occam's Razor
The simplest explanation that fits the evidence is usually correct. Not always — but it's a powerful default.
Circle of Competence
Know what you know. Know what you don't. The most expensive mistakes happen at the boundary.
Hanlon's Razor
Never attribute to malice what can be explained by stupidity (or ignorance, or exhaustion). Saves relationships.
Leverage Points
Small changes in the right place produce big effects. Donella Meadows' framework for thinking about systems.