Blogger Comments:
[1] To be clear, here Doran misconstrues Martin's two different ways of representing one type of structure — the multivariate structure of the experiential metafunction — as two different types of structure, treating the tree schema representation as multivariate, and the co-tangential ellipses representation as orbital (but not multivariate).
The reason why both are representations of multivariate structure is because both represent the same elements of structure and both represent 'a configuration of elements each having a distinct function with respect to the whole' (Halliday & Matthiessen 2014: 390).
[2] To be clear, there are problems with both representations in Martin's Figure 7. Firstly, contrā Doran, the co-tangential ellipses representation does not represent an orbital structure, because it does not represent the non-nuclear elements as satellites of a nucleus.
Secondly, the tree schema representation misunderstands grammatical constituency. In SFL theory, grammatical constituency is modelled as a rank scale of forms, such that clauses consist of groups ± phrases, which consist of words, which consist of morphemes.
So, in Figure 7, the whole is the clause, the parts of the clause are the groups that constitute the clause. The structure, on the other hand, is the relationships between experiential functions assigned to the syntagm of groups.
The relation between a whole and its parts is composition (extension), whereas the relation between function and form is realisation (elaboration + identity).