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Mental Models

Inversion: Think Backwards

Final Exam: Inversion

A graded, one-way final exam on inversion — forward vs. backward thinking, the pre-mortem, avoiding stupidity, anti-goals, the round trip, and when NOT to invert. Pass mark 70%.

20 min Updated Jun 21, 2026

This is the final exam for Inversion. It pulls together everything: the flip from forward to backward thinking, the pre-mortem, Munger’s “avoid stupidity beats seek brilliance,” anti-goals and the personal pre-mortem, the forward-and-backward round trip, and — just as important — knowing when not to invert. Take your time and reason each question through; several look easy until you spot the trap.

Warning:

How this exam works

Read carefully — this exam is final. Each question appears one at a time. Once you submit an answer it is locked for good: there’s no going back, no retry, and no restart. Your score is hidden until the end, where you’ll see a pass/fail verdict. The pass mark is 70%. A few questions ask you to select all correct answers.

Question 1 of 24

What does it mean to “invert” a problem?

Select an answer to continue.

Course Recap

Big picture

Inversion, in one picture

  • Inversion
    • Forward vs. backward
      • Ask how you’d fail, then avoid it — sharper than “how to succeed”
    • The pre-mortem
      • Imagine it already failed; fix the causes before they’re real
    • Avoid stupidity
      • Most of life is a loser’s game — win by fewer mistakes
    • Anti-goals & the round trip
      • Bright lines you refuse; aim → invert → safeguard → advance
    • When NOT to invert
      • Subtractive & cautious — lead forward for bold, creative bets
Success:

Key takeaways

Inversion means asking how you’d guarantee failure and refusing to do those things — a flip that works because failure modes come out specific and few while “how to succeed” stays vague. Scale it up into a pre-mortem to defuse a project before it starts, and into Munger’s strategy of avoiding stupidity to win the loser’s games that make up most of life. Point it at yourself with anti-goals and personal pre-mortems, but always run the round trip — aim forward, invert to stress-test, safeguard, then advance — because inversion is subtractive: it finds what to avoid, never the winning move. Know its limits: it biases toward caution (wrong for bold asymmetric bets) and, overused, breeds paralysis. Invert, fix, then move. Invert — always invert — but never only invert.

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