Halliday & Matthiessen (1999: 601):
The folk model — developed unconsciously and collectively out of shared experience over hundreds of generations — construes and enacts the complexity of being a person by bringing to it a multiplicity of perspectives. It extends the ‘mind’ by refracting it through language, the resource that makes the “cognitive operations” possible and by the same token ensures that they are not subjective but intersubjective.