In the first two passages we are given a picture of 'preselection' as 'predetermination', and so as something approaching 'causation'. Then in [the third] we are told that the relationship is not like that. But we are not told WHY it is not. We are offered instead a metaphor (taken from the terms of the Sydney Grammar itself), but not an explanation as to WHY the relationship is an 'intensive' one.
The reader of these three passages will surely ask: How can it be true that choices made at one stratum are realized in choices at a lower stratum, without this being some type of 'pre-determination'? Passage  presents the relationship as a great mystery!
Among other things, Fawcett does not understand that:
- the theoretical dimension of stratification is organised on the principle of intensive identification — it is not a metaphor, it is what stratification means in this way of modelling language: higher level Value is realised by lower level Token;
- the strata are thus different levels of symbolic abstraction of the same phenomenon — there can be no chain of command across different levels of symbolic abstraction;
- semantic features being realised by the 'preselection' of lexicogrammatical features simply means that features at the higher level of abstraction entail features at the lower level of symbolic abstraction — same phenomenon, different levels of abstraction. For example, the logico-semantic relation of 'cause' can be realised incongruently by the preselection of lexicogrammatical features relating to participants, processes or circumstances at clause rank.
Halliday & Matthiessen (1999: 94) anticipated Fawcett's misinterpretation (in the very same text):
Such selections have been referred to as “pre-selections”, but in order to avoid any connotations of temporal sequence, we prefer the term “selection” for such relations in the ideation base.