The real sting here lies in that verb—*find out*. It's not "decide your purpose" or "choose your path," but discover, as though your why already exists waiting in the world, and the work is recognizing it rather than inventing it. Most of us treat purpose like an exam question demanding we produce the correct answer, when Twain suggests it's more like finding the letter that was always meant for us. A surgeon who trained for years only to realize her true calling was teaching medicine to underserved communities knows this feeling—the moment wasn't about ambition shifting, but about finally seeing what had always been pulling at her attention.