When we say someone is a warm person, we do not mean that they are running a fever. When we describe an issue as weighty, we have not actually used a scale to determine this. And when we say a piece of news is hard to swallow, no one assumes we have tried unsuccessfully to eat it. These phrases are metaphorical--they use concrete objects and qualities to describe abstractions like kindness or importance or difficulty--and we use them and their like so often that we hardly notice them. For most people, metaphor, like simile or synecdoche, is a term inflicted upon them in high school English class: “all the world’s a stage,” “a house divided against itself cannot stand,” Gatsby’s fellow dreamers are “boats against the current, borne back ceaselessly into the past.” Metaphors are literary creations--good ones help us see the world anew, in fresh and interesting ways, the rest are simply cliches: