Full Idea
Standard notions of vagueness all accept borderline cases, and presuppose a higher standpoint from which a judgement of being borderline F, rather than simply being F or being not F, can be made.
Gist of Idea
Standardly vagueness involves borderline cases, and a higher standpoint from which they can be seen
Source
Kit Fine (Vagueness: a global approach [2020], 3)
Book Reference
Fine,Kit: 'Vagueness: a global approach' [OUP 2020], p.52
A Reaction
He says that the concept of borderline cases is an impediment to understanding vagueness. Proposing a third group when you are struggling to separate two other groups doesn't seem helpful, come to think of it. Limbo cases.