# Solve It Backwards

> Inversion, or how asking “what would make this fail?” finds answers faster.

Mental models · 2026-10-14 · by Manas Jain · https://samanar.in/a/inversion

You and a friend are opening a small café near a college in Pune. In a notebook, you write: *How do we make this a success?*

An hour later, the page has three lines. "Good coffee." "Nice vibe." "Instagram."

Now flip the question. *How would we ruin this café?*

The pen starts moving. Open at 11 when classes start at 8. Charge ₹250 for a coffee, then offer a wobbly table and no plug point. Let the Wi-Fi die in exam week. Make people wait twenty minutes for a sandwich.

Ten minutes, a full page. Every line is a mistake you can now avoid.

## What's going on

This is **inversion**: instead of asking how to get what you want, you ask what would guarantee the opposite, and then you stay away from it.

The 19th-century German mathematician Carl Jacobi advised solving hard problems backwards: *invert, always invert*. Charlie Munger, Warren Buffett's long-time partner, carried it into business. In a 1986 graduation speech, he skipped the advice on being happy and listed ways to guarantee **a miserable life**: be unreliable, ignore other people's mistakes, give up after your first big setback.

He liked quoting a rustic: *"I wish I knew where I was going to die, and then I'd never go there."*

Here's the strange part. Most of us can list ways to fail far faster than ways to succeed. **Inversion uses the question we're better at.**

## Think of locking up before a trip

Before a family trip, nobody asks how to make it the perfect holiday. Someone walks through the house checking what could go wrong: the gas knob, the geyser, the back door, the milk delivery.

It's just the last round before the auto arrives. **Avoiding the disasters is most of the plan.**

## Where you'll spot it

- **Pre-mortems.** Psychologist Gary Klein has teams imagine a project has already failed, then write down why. Those reasons are the risks to fix first.
- **Exam prep.** "How would I fail this paper?" Skip past papers, sleep at 3 a.m., leave the hardest chapter for the last night.
- **Keeping customers.** Ask what would make them leave: a slow app, hidden charges, a refund that takes a month. Fix those before adding anything new.

## The catch

Inversion tells you what to avoid. It doesn't tell you what to build. A café with no mistakes can still be **a café nobody remembers**. Clear the path first, then you still have to walk it.

## How to use it

When a plan feels stuck:

1. Write the goal: *a café students love*.
2. Flip it: *how would we make students hate it?*
3. List every honest answer.
4. Turn each one into a rule: **open at 8, sell the seat with the coffee, fix the Wi-Fi first.**

> Most good plans are a list of bad ideas, crossed out.