Not Understanding Halliday (1993) On Rank

Fawcett (2010: 84):

We turn now to the concept of 'rank' — the 'scale' which, with 'unit', provides the major organising principle of the grammar in "Categories". The definition that Halliday gives of it in "Systemic theory" is one of the more puzzling sections of the paper. Here he defines 'rank' in a somewhat opaque manner, writing: 

'Rank' is constituency based on function, and hence 'flat', with minimal layering. (Halliday 1993:4505) 

The meaning of "and hence flat" can be clarified by expanding the last part of Halliday's definition to "and hence represented by diagrams that resemble 'flat trees' rather than 'trees with multiple branching'". And such trees naturally have "minimal layering".

Blogger Comments:

To be clear, Fawcett provides no evidence that he understands Halliday here.  By 'constituency based on function, and hence 'flat', with minimal layering' Halliday means constituency based on minimal bracketing (ranked constituents) rather than maximal bracketing (immediate constituents).  Halliday (1985: 23):

 

 

Minimal bracketing at three ranks yields (Halliday 1985: 21):