Salmon Trapping

Let us call a sentential context semantically transparent if and only if all synonymous expressions are substitutable for one another in it salva veritate. A sentential context is semantically opaque if and only if it is not semantically transparent. Nathan Salmon has boldly advanced a refreshingly crisp theory according to which belief contexts are semantically transparent.1 If he is right, belief contexts are much better behaved than widely suspected.2 Impressive as it is, I do not believe that Salmon's theory is completely satisfactory. I shall not try to refute his theory, however. My aim is more modest. It is to show that his theory, in conjunction with a number of auxiliary but important claims he makes to buttress the theory, seems to lead to semantic opacity of belief contexts.