The latticework
Knowledge sticks when it hangs on a cross-disciplinary scaffold of big ideas.
Charlie Munger's central organising idea. He claimed you need 80 to 90 big mental models, drawn from many different disciplines, hung together in a "latticework" in your head. Isolated facts don't stick. Models without a scaffold don't either.
The point isn't to memorise the list. It's to have enough models that when you face a new situation, two or three different ones reach for it at the same time. You see a price war, and you notice it through the lens of game theory, supply and demand, AND psychology. The lattice is the place where the models compete with each other in your head. That friction is the thinking.
Munger's warning about not doing this: "to the man with a hammer, every problem looks like a nail." If your only model is finance, everything looks like a valuation problem. If your only model is psychology, everything looks like a bias. The lattice is what saves you from torturing reality to fit your favourite hammer.
For most operators, the practical version is: get fluent in the basics of a few fields you'd otherwise ignore (biology, physics, math, history, psychology), not to the level of expertise but to the level of being able to reach for the right model when something rhymes with it.
Examples in the wild
A pricing decision is simultaneously a microeconomics problem, a psychology problem (reference points, loss aversion), and a game theory problem (competitor response). The single-discipline answer misses two-thirds of the picture.
Buffett and Munger explicitly use multiple disciplines on each decision. The financial model is necessary but not sufficient. They overlay competitive dynamics, management quality, customer psychology, and historical patterns from multiple industries.
When you can't figure out why a relationship, project, or team is stuck, try a model from a different field. Usually one of them clicks.
The latticework is one of the mental models we apply through real cases inside the Pareto MBA — a part-time program for professionals who want to think clearly about business.