Full Idea
To know, believe, hope, or fear that A, one must grasp the thought that A. In contrast, to fail to know, believe, hope or fear that A, one need not grasp the thought that A.
Gist of Idea
To know, believe, hope or fear, one must grasp the thought, but not when you fail to do them
Source
Timothy Williamson (Vagueness [1994], 9.3 c)
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.261
A Reaction
A simple point, which at least shows that propositional attitudes are a two-stage operation.