Fawcett's Argument Against Dependency Relations In A Footnote

 Fawcett (2010: 248-9n):

¹¹ … However, in Fawcett & Davies (1992) and Lin & Fawcett (1996), my colleagues and I have demonstrated (in terms of both visual diagrams and a computer implementation) that sister dependency relations can always be interpreted in constituency terms without loss of information. 

… the 'sister-dependency' approach has certain disadvantages. Firstly, it lacks the concept of 'class of unit' (channelling all 'constituency' relations through the 'head'). Secondly, the sister dependency approach raises questions about which element 'depends on' which, when there is frequently not in fact any 'dependency' between them — even between the features in the system network from which the elements are generated.

Blogger Comments:

[1] This is misleading, because it is untrue. In SFL Theory, dependency is modelled as the univariate iterative structure of the logical metafunction, whereas constituency is the basis of the multivariate segmental structure of the experiential metafunction. Halliday (1994: 36):

Because of this, interpreting dependency in constituency terms "loses" the logical dimension of ideational meaning.

[2] This is misleading, because it is untrue. Since interdependency relates formal units — clause, group/phrase, word, morpheme — in complexes, it does not "lack the concept of class of unit", as demonstrated, for example, by nominal group complexes, verbal group complexes, etc. The element Head, on the other hand, identifies the function of one of the formal units in a complex.

[3] This is misleading, because it is untrue. SFL Theory distinguishes two types of interdependency: parataxis and hypotaxis. Parataxis involves units of equal status, whereas hypotaxis involves units of unequal status. The dependency of a unit in a hypotactic complex is demonstrated by its inability to stand alone, as in the case of the dependent clause because they trusted Fawcett without question… .