How can one learn to know oneself? Never by introspection, rather by action.
Johann Wolfgang von GoetheInsofar as he makes use of his healthy senses, man himself is the best and most exact scientific instrument possible. The greatest misfortune of modern physics is that its experiments have been set apart from man, as it were, physics refuses to recognize nature in anything not shown by artificial instruments, and even uses this as a measure of its accomplishments.
Johann Wolfgang von Goethe