We do not belong to those who only get their thoughts from books, or at the prompting of books, it is our custom to think in the open air, walking, leaping, climbing, or dancing on lonesome mountains by preference, or close to the sea, where even the paths become thoughtful. Our first question concerning the value of a book, a man, or a piece of music is: Can it walk? or still better: Can it dance?
Nietzsche, The Gay Science