Presenting Subtypes Of Expansion As The Principal Types

Martin (1992: 178):

In this chapter, following Martin (1983), four main types of logico-semantic relation will be recognised: additive, comparative, temporal and consequential.  And CONJUNCTION will be developed as a system of oppositions at the level of discourse semantics.

Blogger Comment:

[1] The proposed four main types of logico-semantic relation correspond to four subtypes of expansion: comparative, temporal and consequential are subtypes of enhancement and additive is a subtype of extension.  The third type of expansion, elaboration, is omitted altogether.

In contrast, the system of cohesive conjunction (Halliday & Matthiessen 2004: 541) features two subtypes of elaboration: appositive and clarifying, three subtypes of extension: additive, adversative and varying, and four subtypes of enhancement: matter, manner, spatio-temporal and causal-conditional.

In not recognising the three most general forms of expansion, the overall parsimony (or "elegance") of the theory is compromised.  See Occam's razor.

[2] An argument justifying the reconstrual of the grammatical system of textual metafunction (cohesive conjunction) as a semantic system of the logical metafunction (CONJUNCTION) has not been presented.