Halliday & Matthiessen (2004: 605-6):
… projection includes both hypotactic projection of ideas or reports and pre-projected facts serving in a ‘mental’ or ‘relational’ clause. A hypotactic projection is always ‘subjective’; the speaker is represented explicitly the Senser or Sayer. A pre-projected fact in a ‘mental’ clause is like hypotactic projection in representing the assessment as ‘subjective’ — the speaker is explicitly represented as the Senser. In contrast, a pre-projected fact in a ‘relational’ clause represents the assessment as ‘objective’.