In the intensive type, the relationship between the two terms is one of sameness; the one ʻisʼ the other. The problem is to specify what exactly this means [...] In the case of attributive mode, in which some qualitive attribute is assigned to a ʻcarrierʼ, the meaning is ʻ 'x' is a member of the class 'a' ʼ. So 'Sarah is wise' means ʻSarah is a member of the class of wise onesʼ; 'John is a poet' ʻJohn is a member of the class of poetsʼ [...] In the identifying mode the meaning is ʻ 'a' serves to define the identity of 'x' ʼ. Here 'a' and 'x' are two distinct entities, one that is to be identified, and another that identifies it. The relationship between them, therefore, is not one of class membership, since that would not serve to identify: we may say 'Sarah is wise', but this means that there are, or may be, other wise ones besides Sarah. If we say 'Sarah is the wise one', or 'Sarah is the wisest', this does identify her; she is the only member of the class.
- Halliday (1985), a pag.114-115