Halliday & Matthiessen (2004: 657):
This kind of nominalising metaphor probably evolved first in scientific and technical registers, where it played a dual rôle: it made it possible on the one hand to construct hierarchies of technical terms, and on the other hand to develop an argument step by step, using complex passages ‘packaged’ in nominal form as Themes. It has gradually worked its way through into most other varieties of adult discourse, in much of which, however, it loses its original raison d’être and tends to become merely a mark of prestige and power.