Full Idea
We attribute to a subject beliefs that are obvious logical consequences of beliefs already attributed to him.
Gist of Idea
We assume people believe the obvious logical consequences of their known beliefs
Source
Jaegwon Kim (Philosophy of Mind [1996], p.135)
Book Reference
Kim,Jaegwon: 'Philosophy of Mind' [Westview 1998], p.135
A Reaction
Depends what you mean by 'obvious'. Presumably they must be judged obvious to the believer, but only if they have thought of them. We can't believe all the simple but quirky implications of our beliefs.