The dialogue “We know what we are, but know not what we may be” was used by Ophelia, in Hamlet, Act 4, Scene 5. Ophelia is making a good sense here. You may use this quote, whenever you want to say, “Live in present and don’t worry about future.” You may also use this quote in an inspirational way, when you want to say, “realize your potential, because you only know very little about yourself.”