I once saw a sign in a restaurant that read, ‘You are what you eat.’ I pointed out to the waitress that if we are what we eat, then we couldn’t be something until we have eaten something, But we can’t eat something unless we are something. therefore, it’s not true that we are what we eat. The waitress, unschooled in the finer points of self-refuting arguments, looked at me and said , ‘you’ll have to talk to the manager.”

                                                                                     – Greg Koukl (Tactics; page 119)