Considered from the the perspective of group rank as opposed to clause rank meanings, all of the topical Themes in [6:30] are in fact 'interpersonal' ones: first and second person pronouns (I, you, you, you, I, we, you, you, we) and the metaphorical modulation my responsibilities. So the method of development of this text is an interactive one: the sitting member is concerned to engage his constituent. The association of unmarked Theme and Subject in English means that these interpersonal considerations are better pursued during the discussion of modal responsibility in 6.3.4 below. It is important to note at this point however that a pattern of Theme selection which foregrounds interpersonal meaning will not lend itself to he experientially oriented macro-Theme, hyper-Theme, Theme interaction reviewed above. It is for this reason that school rhetoric has long cautioned against writing in the first person (although it has also long forgotten why this is so).
 This confuses the textual metafunction (method of development) with the interpersonal metafunction (speaker-addressee 'engagement').
 To be clear, the "interaction" in this written monologic text is merely the use of the 'speech rôle' pronouns I, we (speaker) and you (addressee).
 This confuses the textual metafunction (Theme and method of development) with the interpersonal metafunction (Subject as the carrier of modal responsibility).
 To be clear, in saying 'a pattern of Theme selection which foregrounds interpersonal meaning' Martin means 'speech rôle' personal pronouns serving as topical (experiential) Themes.
 This is even manifestly untrue within Martin's model, since macro-Themes (Introductory Paragraphs) and hyper-Themes (Topic Sentences) can "predict" the appearance of (anaphorically referring) personal pronouns as Themes.
 Clearly, any proscriptions against writing in the first person do not derive from writers being unable to apply Martin's pedagogical model.
In SFL theory, this is a matter of variation according to the text type (register) and the situation type (cultural context) it realises. Prescription and proscription arise in pedagogy when usuality (modalisation) is reconstrued as obligation (modulation).