A careful balance needs to be struck between our confidence in the parts of the universe we know and our suspicion of the universe we don’t know. Drawing on Rumsfeldian parlance once again—your known knowns, your known unknowns, and your unknown unknowns, or “unk-unks”—I think the art of engineering, or being successful in business or life, for that matter, lies in how one finds the unk-unks and makes them “kn-unks,” and how one respects the possibility for more to be found . . . or never discovered.
