Full Idea
If language is like a tree, then penumbral connection (logic holding among indefinite sentences) is the seed from which the tree grows, for it provides an initial repository of truths that are to be retained throughout all growth.
Gist of Idea
Logic holding between indefinite sentences is the core of all language
Source
Kit Fine (Vagueness, Truth and Logic [1975], 2)
Book Reference
'Vagueness: a Reader', ed/tr. Keefe,R /Smith,P [MIT 1999], p.129
A Reaction
A nice incidental insight arising from his investigation of vagueness. People accept one another's reasons even when they are confused, or hopeless at expressing themselves. Nice.