“The theme is what is being talked about, the point of departure for the clause as message”
Source: 1970s and later, Cohesion in English (English Language), 1976, p. 212.
Context: The theme is what is being talked about, the point of departure for the clause as message, and the speaker has within certain limits the option of selecting any element in the clause as thematic.
Help us to complete the source, original and additional information
Michael Halliday 23
Australian linguist 1925–2018Related quotes

Vol. II, Ch. IV, p. 104.
(Buch II) (1893)

To Colin Powell, then chairman of the Joint Chiefs of Staff, in the 1990s, on Bosnia, recounted in Madam Secretary (2003), p. 182
2000s

“Opinions, yes; convictions, no. That is the point of departure for an intellectual pride.”
Anathemas and Admirations (1987)
“Set out from any point. They are all alike. They all lead to a point of departure.”
Pártase de cualquier punto. Todos son iguales. Todos llevan a un punto de partida.
Voces (1943)
NANOG mailing list http://www.mail-archive.com/nanog@merit.edu/msg00981.html (2004)

"The West Should Fear the Growth of State Capitalism," http://www.telegraph.co.uk/finance/economics/7883061/The-West-should-fear-the-growth-of-state-capitalism-Ian-Bremmer.html The Daily Telegraph (July 10, 2010).

On Certainty (1969)
Context: 105. All testing, all confirmation and disconfirmation of a hypothesis takes place already within a system. And this system is not a more or less arbitrary and doubtful point of departure for all our arguments; no it belongs to the essence of what we call an argument. The system is not so much the point of departure, as the element in which our arguments have their life.

“Snow White” [play], p. 324.
The Teachings of Don. B: Satires, Parodies, Fables, Illustrated Stories, and Plays of Donald Barthelme (1992)