Halliday & Matthiessen (1999: 243):
What for example would be the semantic interpretation of [the transcategorisations] shakiness, awakening, analysis, development? Here we find ourselves using precisely the terms of our own metalanguage in the definition: ‘quality of being shaky’, ‘process of being awake, or causing to become awake’, ‘process of analysing, developing’. When this happens, it is a signal that a phenomenon of this other kind — quality or process — is being treated as if it was a thing. The grammar has constructed an imaginary or fictitious object, called shakiness, by transcategorising the quality shaky; similarly, by transcategorising the process develop it has created a pseudo-thing called development.