Halliday & Matthiessen (2014: 543):
Note the following pair (Figure 7-24):
In (a) the clause that Caesar was dead is projected as an ‘idea’ by Mark Antony thought. It is therefore a separate, hypotactic clause; and hence
(i) it cannot be preceded by the fact;
(ii) it cannot be replaced by Caesar’s death;
(iii) it can be quoted: ‘Caesar is dead,’ thought Mark Antony;
(iv) it can be replaced by the substitute so: Mark Antony thought so.
In (b), however, the clause that Caesar was dead, although it is a projection, is not projected by Mark Antony regretted, which is a clause of emotion not of cognition. It is not an idea but a fact; hence it is embedded, and hence
(i) it can be preceded by a ‘fact’ noun;
(ii) it can be replaced by a nominal group Caesar’s death;
(iii) it cannot readily be quoted: Mark Antony regretted, ‘Caesar is dead’ is very forced; and
(iv) it can be replaced by the reference item it, but not by the substitute so: Mark Antony regretted it (not so).
The form Mark Antony dreaded that Caesar was dead is an example of a type that allows both interpretations, and hence is ambiguous: as idea (hypotactic), ‘he thought (and wished otherwise)’, or as fact (embedded), ‘he was afraid because’.
Blogger Comments:
In the case of Mark Antony regretted, ‘Caesar is dead’, the projection ‘Caesar is dead’ is an idea (ranking clause), not a fact (embedded clause). Here the verb regretted serves as a cognitive — rather than emotive — mental Process, the lexical choice adding an 'emotive' feature to the cognition. This is the same principle as lexical choice adding a behavioural feature to a verbal Process, as in 'Caesar is dead', mumbled Cassius.