Business thinker

Charlie Munger's inversion and latticework of models

Updated 4 November 2026

Not affiliated with or endorsed by Charlie Munger or their companies.

Charlie Munger, Warren Buffett's long-time partner at Berkshire Hathaway, is known for inversion: solving a hard problem backward by asking what would guarantee failure. He also described a latticework of mental models, seeing a problem through several fields at once. This page explains both from Poor Charlie's Almanack, the collection of his talks published by Stripe Press, and from the Berkshire letters, and turns them into a review you can run on your own plan.

Inversion: solve it backward

Stripe Press's page for Poor Charlie's Almanack quotes Munger: "Many hard problems are best solved when they are addressed backward. Invert, always invert." In practice, instead of listing how a plan will succeed, you list the concrete ways it would fail, then check the plan avoids each one.

Buffett's 1996 letter shows the same habit at Berkshire. It says Berkshire tries to "reverse engineer" its future, bearing in mind Charlie's dictum: "All I want to know is where I'm going to die so I'll never go there." If the company can't tolerate a possible consequence, however remote, it steers clear of the action that could cause it.

For a business, the useful split is between failures you could recover from and ones you couldn't. A bakery chain opening four shops at once on a bank loan might survive losing its flour discount, but not running out of cash before the new shops break even. The second kind is avoided outright, not weighed against the upside.

A latticework of mental models

The same Stripe Press page quotes Munger saying you've got to have models in your head and array your experience, both vicarious and direct, on a latticework of models. The point is breadth: a plan that looks fine through a finance lens may look different through incentives (who gains from each choice), base rates (how often similar plans worked), or second-order effects (what changes after the first change). Which models to use is a choice you make for the case; the sources don't give a fixed list.

Wonderful businesses at fair prices

Buffett's 2023 letter, written after Munger's death, recounts Munger's advice from 1965: now that Buffett controlled Berkshire, add wonderful businesses purchased at fair prices and give up buying fair businesses at wonderful prices. Buffett writes that he followed it, with much back-sliding. For a purchase decision, the inverted question is whether you are buying something good at a fair price, or something mediocre that only looks cheap.

How to apply it to your own plan

1. Write the goal in one line: what, by when, measured how.
2. Invert it: list 8 to 12 specific ways to make sure it fails, each with its mechanism.
3. Mark the failures the business could not recover from, and write a rule that keeps you away from each.
4. Check each failure against the plan: does the plan avoid it, partly avoid it, or walk into it?
5. Re-read the plan through three to five models from different fields, and note what each one shows.
6. Change the plan to remove the unrecoverable failures first, and give each change an owner.

What the sources say, and what they don't

The two Munger quotations come from Stripe Press's page for Poor Charlie's Almanack; the dictum and the 1965 advice are as Buffett reports them in the 1996 and 2023 letters. Munger's longer talks are in the book; we didn't summarise them here because we couldn't check their text online. The list of models in the skill below is ours, not Munger's.