Full Idea
A blurry border is still a border.
Gist of Idea
A blurry border is still a border
Source
Stewart Shapiro (Philosophy of Mathematics [1997], 8.3)
Book Reference
Shapiro,Stewart: 'Philosophy of Mathematics:structure and ontology' [OUP 1997], p.255
A Reaction
This remark deserves to be quoted in almost every area of philosophy, against those who attack a concept by focusing on its vague edges. Philosophers should focus on central cases, not borderline cases (though the latter may be of interest).