Halliday & Matthiessen (1999: 119):
The logico-semantic relation of condition, which is prototypically construed as a form of enhancement, could also be construed as a kind of projection … Words such as supposing and assuming are verbs of projection which have come to function as conjunctions in conditional figures; while other words such as imagine and say retain more of their projecting force. … This is an uncertain region in which a figure hangs in the air, so to speak, suspended between the hypothetical material plane and the semiotic one.
