Misconstruing Substitution As Continuity

Martin (1992: 233):

Where the Mood changes, but the Residue is constant, the realisation so ^ Finite ^ Subject is possible:

NEW MOOD
[4:178] Ben won the race,
            but later so did Carl.

Blogger Comments:

[1] Contrary to the claim, part of the Residue (the substitution) and part of the Mood (the Finite) are constant across clauses here.

[2] In SFL theory, so marks an instance of substitution, a resource of textual cohesion, as shown by the variant ordering of elements; see Halliday & Matthiessen (2004: 564-5). Here it is misconstrued as continuity, which in turn is misconstrued as logical instead of textual.

Ben	won		the race
Subject	Finite	Predicator	Complement
Mood		Residue

but	later	so		did	Carl
	circumstantial Adjunct	Predicator	Complement	Finite	Subject
	Residue			Mood