On 'The Main Components Of A Systemic Functional Grammar'

Fawcett (2010: 36):

The diagram in Figure 4 brings together these two pairs of concepts to define the four components that are essential for modelling any semiotic system. It provides a framework for thinking about language in terms of (1) the potential and (2) the many possible instances of that potential, and to do so at the two levels of (a) meaning and (b) form. The four components of the model are defined by the intersections of these two pairs of concepts. 

Blogger Comments:

On the one hand, Figure 4 presents a flow chart for text generation by computer, not a systemic functional model of grammar.  It is also inconsistent with SFL theory in that it presents the architecture of the theory in terms of interactions between modules instead of relations along dimensions; see Halliday & Webster (2009: 231).

On the other hand, Figure 4 is internally inconsistent.  Firstly, the 'potential' column presents realisation rules as the form that realises the system of meaning.  To be consistent with the level of meaning, the level of form would need to be a 'system network of choices in form'.  To be consistent with SFL theory, the realisation rules would need to be located in the system of meaning.

Secondly, the 'instance' column presents structure as the form that realises features of meaning.  That is, it presents the axial relation between paradigm (features) and syntagm (structure) as a stratal relation between meaning and form.

Thirdly, the 'form' row presents structure as an instance of realisation rules as potential.  That is, it presents the axial relation between paradigm (realisation rules) and syntagm (structure) as a relation of instantiation between potential and instance.

Any theoretical advantages afforded by such inconsistencies need to be demonstrated, and their value weighed against their consequences for the theoretical architecture as a whole.