Full Idea
Inexact knowledge is a widespread and easily recognised cognitive phenomenon, whose underlying nature turns out to be characterised by the holding of margin of error principles.
Gist of Idea
We have inexact knowledge when we include margins of error
Source
Timothy Williamson (Vagueness [1994], 8.3)
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.227
A Reaction
Williamson is invoking this as a tool in developing his epistemic view of vagueness. It obviously invites the question of how it can be knowledge if error is a possibility. A very large margin of error would obviously invalidate it.