Halliday & Matthiessen (1999: 595):
The congruent ideational system separates out consciousness from the rest of our experience and construes it as a domain of sensing, embodying a Medium + Process complementarity where conscious beings (Medium) perceive, think, want, feel (Process). Sensing is thus ‘mediated’ through the Senser; and this process may project ideas into semiotic existence. This domain of Sensers sensing (that …), which is construed in congruent system, is taken over in cognitive science. However, it is not taken over as being itself a theory of conscious processing; instead, it is treated as a phenomenon — that is, sensing is turned into the object of study.