Inversion

Overview

Carl Gustav Jacobi's maxim "man muss immer umkehren" (invert, always invert), operationalized by Charlie Munger: many problems are easier solved backward. Instead of "how do I achieve X?", ask "what would guarantee NOT-X — and how do I avoid all of that?" Munger: "All I want to know is where I'm going to die, so I'll never go there." Forward thinking samples from paths to success (huge, fuzzy space); inversion enumerates paths to failure (smaller, sharper space) — and failure paths are where blind spots hide, because nobody was looking there.

When to Use

• Vague goals: "make this fast/clean/reliable/good" → invert to the concrete badness to eliminate
• Stuck on a direct approach
• Designing guardrails, reviews, checklists, on-call runbooks
• Evaluating a decision: before asking "why will this work?", ask "what would make this a disaster?"

The Procedure

1. State the goal, then flip it: write the anti-goal explicitly ("users churn immediately", "the migration corrupts data", "nobody can read this code").
2. Enumerate reliable ways to achieve the anti-goal. Be a competent saboteur: how would you ensure churn / corruption / unreadability? Concrete mechanisms, not categories.
3. Audit the current plan against the sabotage list. Every mechanism the plan doesn't block is a finding.
4. Convert to avoidance rules. Often the entire deliverable: a short "never do these" list beats a long "try to do these" list.