Lakoff and Johnson explain why Aristotle must reduce metaphor to linguistic deviance: Aristotle employs the metaphors “Ideas are Essences” and “Essences are Forms,” and on this basis argues that “things in the world . . . can be directly grasped by the mind.  Ideas therefore are aspects of the physical world.  It is not possible for one idea to be conceptualized in terms of another.  It is not possible for part of the logic of one idea to come from another idea.  The logic of an idea, for Aristotle, is part of the structure of the external world.  Because a domain is in the world, not just in the mind, a cross-domain mapping would have to be part of the world.  But that is impossible.  In the world, things exist as distinct kinds, as part of distinct categories.  Each essence has its own inherent logic and not that of another kind of thing.  The idea that the essential form of a thing could be that of another kind of thing makes no sense at all in the Aristotelian worldview.”