But it is the analysis of texts in IFG, of course, that constitutes the major evidence as to how Halliday sees the structure of what we shall later call 'instances of syntax'. And in evaluating these representations we shall find — contrary to what you might expect — that they raise serious theoretical problems. Moreover, in the course of Chapter 7 it becomes clear that, even if you feel completely happy about the representations of structure in IFG, Halliday's model additionally needs an integrating syntax of the sort proposed here in Part 2.
 In SFL theory, there is an important distinction between function structure and formal syntagm (syntax).
 It will be seen in the examination of this later discussion that Fawcett confuses the theoretical dimension of instantiation with the theoretical dimension of delicacy.
 It will be seen in the examination of this later discussion that the function structures do not raise serious theoretical problems. For example, Fawcett will present the double layering of interpersonal clause structure as a theoretical problem.
 Fawcett's 'integrating syntax' depends on an incompatible theoretical architecture (semantics as system, grammar as formal syntagm), and so cannot be included in the SFL model without sacrificing theoretical consistency.