Halliday & Matthiessen (2014: 718):
As we have seen, grammatical metaphor of the ideational kind is primarily a strategy enabling us to transform our experience of the world: the model of experience construed in the congruent mode is reconstrued in the metaphorical mode, creating a model that is further removed from our everyday experience – but which has made modern science possible. At the same time, there are also textual and interpersonal consequences of this metaphorical realignment in the grammar: ideational metaphor can be a powerful textual resource for managing the creation of text, creating new mappings between the ideational and textual quanta of information; and it can also be a powerful interpersonal resource for organising the ongoing negotiation of meaning, creating new mappings between the ideational and interpersonal propositions/proposals.