more on this theme | more from this thinker | more from this text
Full Idea
If a word is vague, there are or could be borderline cases, but non-vague expressions can also have borderline cases. The essence of vagueness is to be found in the idea vague concepts are concepts without boundaries.
Gist of Idea
Vague concepts are concepts without boundaries
Source
Mark Sainsbury (Concepts without Boundaries [1990], Intro)
Book Ref
'Vagueness: a Reader', ed/tr. Keefe,R /Smith,P [MIT 1999], p.251
A Reaction
He goes on to say that vague concepts are not embodied in clear cut sets, which is what gives us our notion of a boundary. So what is vague is 'membership'. You are either a member of a club or not, but when do you join the 'middle-aged'?