Halliday & Matthiessen (1999: 91):
The examples of meronymies given above come from the region of 'participant' within the ideation base. It is not clear to what extent, or in what sense, meronymic taxonomies extend beyond that region. We can certainly recognise that processes have phases — 'begin to do, keep doing, stop doing'; but it is not immediately clear that these form a process meronymy analogous to the parts of a participant. Although we might reconstrue he began to dance metaphorically as the beginning of his dance on the model of 'the beginning of the book', this is a metaphorical reification of the process 'dance' and we have to be cautious in interpreting the implications for the congruent process 'dance'. If we probe a little further, we can see that process phase is concerned with the occurrence of a process in time — its temporal unfolding: 'begin to do' means 'begin to be actualised (to occur) as doing in time'. In contrast, participant meronymy is not tied to the existence of a participant in referential space.