Halliday & Matthiessen (1999: 60, 62):
Some ‘simple things’ are metaphorical; the remainder are referred to as ‘ordinary’, and these are either conscious or non-conscious (this is the distinction that is actually made in the semantic system, not animate/inanimate or human/non-human). … Again, a number of simple qualities are metaphorical; of the remainder, the ‘ordinary’ qualities, one subtype is qualities of projection and the other is qualities of expansion.