The contemporary theory of metaphor

These famous lines by Thomas and Stevens are examples of what classical theorists, at least since Aristotle, have referred to as metaphor: instances of novel poetic language in which words like "mother," "go," and "night" are not used in their normal everyday sense. In classical theories of language, metaphor was seen as a matter of language, not thought. Metaphorical expressions were assumed to be mutually exclusive with the realm of ordinary everday language: everyday language had no metaphor, and metaphor used mechanisms outside the realm of everyday conventional language.