Inversion

How it works

Most people approach problems head-on: “How do I get fit?” “How do I make this project succeed?” “How do I build a great team?”

Inversion flips the question. Instead of chasing success, you map out failure — then work backwards.

The mathematician Carl Jacobi captured it in two words: “Invert, always invert.” Charlie Munger made it a cornerstone of his decision-making toolkit, arguing that many hard problems become easier when you reverse them.

The process has three steps. First, define what you’re trying to achieve. Second, ask: “What would guarantee the opposite outcome?” List everything that would ensure failure. Third, look at your list and ask which of those failure conditions currently exist in your situation — then eliminate them.

Case study: How Florence Nightingale saved the British Army

In 1854, Florence Nightingale arrived at a British military hospital in Scutari during the Crimean War. The death rate among wounded soldiers was 42%. Rather than asking “how do I heal these men?” — the forward question every doctor was already trying to answer — Nightingale inverted: “What is killing them?”

She discovered the answer wasn’t battlefield wounds. It was the hospital itself. Open sewers ran beneath the building. Ventilation was nonexistent. Patients lay in their own waste. She didn’t introduce new medical treatments. She scrubbed the floors, opened the windows, improved the drains, and demanded clean bedding.

Within months the death rate fell to 2%. Nightingale didn’t save the British Army by finding better cures. She saved it by removing the causes of death. Pure inversion.

Real-world examples

Investing. Warren Buffett doesn’t try to find the best investments. He starts by listing all the ways people lose money — overpaying, investing in things they don’t understand, using leverage — and avoids those. His first two rules: “Rule 1: Don’t lose money. Rule 2: Don’t forget Rule 1.”

Health. Instead of asking “What’s the perfect diet?”, invert: “What definitely makes me unhealthy?” Ultra-processed food, no sleep, no movement, chronic stress. Eliminate those and you’re already ahead of most optimization strategies.

Project management. Before a product launch, ask: “If this product fails spectacularly, what went wrong?” Poor onboarding, confusing pricing, no customer support. Now you know exactly what needs to be bulletproof.

When to use it

Inversion is most powerful when you’re stuck on a forward-looking question, when you’re planning something important and want to avoid preventable failures, when you’re evaluating a decision and want to stress-test it, and when you want to simplify a complex problem by subtracting rather than adding.

Common mistakes

The most common mistake is stopping at the inversion. The point isn’t just to identify what could go wrong — it’s to take action on those insights. The second mistake is using inversion alone. It’s a complement to forward thinking, not a replacement. Use both: brainstorm what success looks like, then invert to find the landmines between here and there.

Try it now

Take any goal you’re currently working on. Write it down. Then complete this sentence: “This will definitely fail if ___.” List at least five things. Now look at your list — which of those failure conditions are currently present in your situation?

Related models

These models complement Inversion — they address similar situations from different angles.