Martin (1992: 327):
The analysis of lexical relations in two texts presented below will show some of the ways in which this characterisation of the differences between message parts and lexical items needs to be extended in order to present a full account of experiential cohesion in text.
 Here message parts (discourse semantic stratum) and lexical items (lexicogrammatical stratum) are misconstrued as being of the same level of symbolic abstraction. Moreover the former is construed as a structural unit of discourse semantics, whereas the latter is the output of the most delicate systems of lexicogrammar.
 In SFL theory, cohesion is the non-structural resource of the textual metafunction. While the textual metafunction is concerned with weaving ideational and interpersonal together as information, the experiential metafunction is concern with the construal of experience as meaning.