Martin (1992: 545-6):
Any such scaling of fields with respect to degree of specialisation and technicality, alongside the scaling of oral and written (especially metaphorical) modes this implies, runs the risk of being misinterpreted as valuing different fields in different ways. This kind of ranking should not be read into the networks at the level of field. However it is obvious that fields are valued in different ways and so ranked by all cultures: in Australia, for example, being young, non-anglo, working class or female vastly restricts the meaning potential human cultures otherwise afford. Discourses of generation, gender, ethnicity and class channel subjects in very different ways according to the coding orientations they enjoy. It is the responsibility of the plane of ideology to make the nature of this channeling clear, deconstructing the momentum and inherent contradictions which allow it to evolve.
 Alongside the mode system distinction of oral vs written (textual metafunction), Martin includes the distinction of oral vs written transmission in his discussion and system of field (ideational metafunction).
 This is misleading. It is not any mode that is metaphorical. Instead, the language of some modes may deploy more grammatical metaphor than the language of other modes. For example, ceteris paribus, there is typically more use of ideational metaphor in the language of written mode than in the language of spoken mode.
 This simplistic analysis is falsified, for example, by the considerable number of young, non-"Anglo", female and formerly working class academics in Australian universities. Compare also the 'coding orientation' of the present blogger, whose ancestral lines include Irish, German, Jewish and Australian indigenous, and who comes from a family where the father laboured as an employee on factory floors and building sites.
 The model of the plane of ideology (pp573-88) will be assessed in terms of how well it meets this responsibility.