$PI Never let others tell you what you can or can’t do. For example, Beethoven—everyone said that his deafness meant he could never become a great musician, but did he actually listen? No—he didn’t. In this world, successful people are probably only of two kinds: madmen and fools. Madmen have wild, out-of-this-world ideas—ideas that are so unbelievable that, to “normal people,” they seem impossible to achieve. Ignoring the mockery of “normal people,” they remain obsessed and grind on, forging ahead until they make the impossible possible. Elon Musk is one of these people. People like this all have nearly obsessive, maddening ideas. As for fools, it’s simpler: they decide on a direction, follow the right people, and stubbornly persist—until time turns their foolish persistence into a return and a reward.