HomeFrameworksThinking & Mental Models › Inversion
// framework

Inversion

Carl Jacobi (mathematician); Charlie Munger (business application)

Solve problems by flipping them — ask what would guarantee failure, then do the opposite. The brain predicts failure better than success when you frame the question right.

// description

A thinking technique that solves problems by inverting them — instead of asking "how do I succeed?" ask "how do I make sure I fail?" Then avoid those things. Often reveals blind spots, hidden risks, and assumptions that forward-looking analysis misses.

// history

The mathematician Carl Jacobi advised "man muss immer umkehren" (invert, always invert) as a mathematical problem-solving technique. Charlie Munger, Warren Buffett's long-time business partner, popularised inversion as a mental model in investing and business. Munger noted that most serious mistakes can be avoided simply by asking: what behaviour would guarantee failure? Then do the opposite. He applied this to Berkshire Hathaway's decision-making culture.

// example

Instead of asking "how do I build a successful Etsy shop?", ask "what would guarantee my Etsy shop fails?" Answers: poor product photos, no keyword research, no new listings for months, ignoring reviews, pricing too low to be profitable. Now flip those into your to-do list: invest in quality photos, research keywords obsessively, list consistently, respond to reviews, price for sustainable margin.

// katharyne's take

Inversion is my favourite mental model for pre-mortems and stress-testing plans. Before a launch, I ask: what would need to happen for this to completely bomb? The answers are usually very obvious once you ask the question — and they reveal prep work I hadn't done. The brain is weirdly good at predicting failure when you frame the question that way. It's uncomfortable but deeply useful.

// creative uses
// quick actions
// prompt ideas
Apply inversion to my goal of [describe your goal — e.g. building a profitable KDP portfolio, growing my Etsy shop to $X/month, launching a successful course]. List every specific thing I could do to guarantee I fail at this. Be thorough and honest. Then flip each failure point into a concrete action or principle I should follow instead.
I'm planning to [launch a new product / enter a new niche / start on a new platform]. Before I commit, run a pre-mortem using inversion: imagine it's 6 months from now and this has completely failed. What are the most likely reasons it failed? Work backwards from failure to help me identify the specific risks, assumptions, and preparation gaps I need to address before I start.
Using inversion, audit my current [Etsy shop / KDP account / email list / course platform] for the most common failure modes in my niche. What behaviour would — if continued — guarantee my [account gets flagged / shop stagnates / list goes cold / students drop out]? For each failure mode, give me a specific policy or habit I should implement now to prevent it.
See also: First Principles Thinking, Second-Order Thinking, Pareto Principle
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