Full Idea
States that have the same intrinsic properties - the same neural/physical properties - may have different contents if they are embedded in different environments.
Gist of Idea
Two identical brain states could have different contents in different worlds
Source
Jaegwon Kim (Philosophy of Mind [1996], p.146)
Book Reference
Kim,Jaegwon: 'Philosophy of Mind' [Westview 1998], p.146
A Reaction
This is a way of expressing externalism. It depends what you mean by 'contents'. I struggle to see how "H2O" could be the content of the word 'water' among ancient Greeks.