"Mental representations" are the coin of contemporary cognitive psychology, which proposes to explain the etiology of subjects' behavior in terms of the possession and use of such representations. "How does a subject manage to move through her darkened bedroom without stumbling over the furniture? She has an accurate mental representation of the room's layout, knows her initial position in the room, and is able to use this representation, in roughly the way a mariner uses a chart, to navigate through the room." "How does a sighted subject manage to recover information, available in the retinal image, about 'what's where' in her environment? She computes a series of representations, using information present in the retinal image, that eventuates in a three-dimensional representation of the distal objects present in the subject's visual field." "Why do native speakers of English have difficulty recognizing the grammaticality of so-called garden-path sentences...