Halliday & Matthiessen (1999: 598):
… the metaphorical reconstrual of mental processes effaces the Sensers involved in these processes — the conscious beings, prototypically human, who are thinking, knowing, believing, remembering and so on. This effacement of the Sensers is of course not accidental: in fact, one central feature of the way in which cognitivists reconstrue mental processes in metaphorical terms is that the grammatical metaphor makes it possible to distance the account from our everyday experience. …Given this orientation, it would thus seem that the unified senser existing as a person who “senses” is an illusion construed by the grammar as part of a folk theory of our own sense of conscious processing.