One of Charlie Munger’s favorite stories is about the man who only wanted to know where he would die, so he would never go there. Inversion is all about solving a problem backward. Figure out each step from the end backwards to where you are now, and either make sure you do each step, or avoid doing each step. Thinking backwards, and inversion, usually means subtracting things that could go wrong. That’s the subtle power of inversion, which is it forces you to think using subtraction, instead of the normal forward thinking, which is built on addition. Don’t think about what would make a good life, think about things that would result in a miserable life.
Inversion can originally be credited to Carl Jacobi. According to wikipedia:
One of his maxims was: ‘Invert, always invert’ expressing his belief that the solution of many hard problems can be clarified by re-expressing them in inverse form.
Watch this video to hear Charlie Munger talk about this himself. He speaks far more eloquently than I write. Invert your thinking, and the problem becomes easier to solve.