Halliday & Matthiessen (1999: 137-8):
Sensing projects ideas into existence; the projection may take place either through cognition or through desideration, for example (from Pinter, The Birthday Party):I just thought —> I’d tell you that I’d appreciate it.I think —> I’ll give it up.They want —> me to crawl down on my bended knees.Thus the idea ‘I’ll give it up’ is created by the process of thinking; it does not exist prior to the beginning of that process. Similarly, the idea ‘me to crawl on my bended knees’ is brought into hypothetical existence by the process of wanting.