Martin (1992: 489):
Point is the discourse complement of method of development. Where Theme ties the text down, point elaborates it, developing it as news. A much greater range of meanings with be realised in New than Theme, though not a random set. A text's principle [sic] strings and chains will still be there, constrained by cohesive harmony; but there will be lesser [sic] strings and chains and odds and ends as well. A text is never hermetically sealed; a text, like the system behind it, is a dynamic open process — and point is a source of openness: a resistance to the closure predicated on cohesive harmony and method of development.
Blogger Comments:
[1] Again, it is instructive to compare these metaphors with Martin's model. Martin's point is, again, a mixture of writing pedagogy and linguistic theory. Martin supplies the writing pedagogy, rebranding paragraph summary as hyper-New, and text summary as macro-New, whereas Halliday supplies the linguistic theory: New as information deemed unrecoverable to the listener (textual metafunction).
Martin's point is the accumulation of experiential meaning that is highlighted as New information and included in a paragraph summary and text summary. Importantly, interpersonal and textual meanings are also highlighted as New information — e.g. modal adjuncts such as allegedly and conjunctive adjuncts such as nevertheless, respectively — but these are ignored in this focus on experiential meaning.
Martin's deployment of the linguistic theory is internally inconsistent, given that New information is located on the phonological stratum, and yet construed as an element of the clause (lexicogrammar), rather than the information unit.
[2] Theme, as the point of departure of a message, does not "tie a text down" — anymore than airports, as points of departure during a holiday, "tie a holiday down".
[3] Point does not "develop the text as news". New is information that is presented as unrecoverable to the listener; hyper-New is a paragraph summary of what has already been written; and macro-New is a text summary of what has already been written.
[4] Cohesive harmony does not constrain a text. Hasan's cohesive harmony describes the synergy of the non-structural resources of the textual metafunction, cohesion, and the meanings of the experiential metafunction (and potentially the interpersonal metafunction).
[5] To be clear, system and text are related by the vector of instantiation. In SFL theory, 'system' is short for 'system–&–process' (Halliday & Matthiessen 1999: 507), and text is an instance of the 'system–&–process'. The unfolding of the text at the instance pole of the cline of instantiation is the process of logogenesis.
[7] By definition, New information may be "a source of openness", but summaries of what has already been written (hyper-New and macro-New) are not. They are repetitions of meanings internal to the text.
[8] This is manifestly untrue. See [2] and [4] above.