It is generally assumed that if it is possible to believe that p without believing that q, then there is some difference between the object of the thought that p and the object of the thought that q. This assumption is challenged in the present paper, opening the way to an account of epistemic opacity that improves on existing accounts, not least because it casts doubt on various arguments that attempt to derive startling ontological conclusions from seemingly innocent epistemic premises.

I offer a theory of propositional attitudeascriptions that reconciles a number of independently plausiblesemantic principles. At the heart of the theory lies the claim thatpsychological verbs (such as ``to believe'' and ``to doubt'') vary incontent indexically. After defending this claim and explaining how itrenders the aforementioned principles mutually compatible, I arguethat my account is superior to currently popular hidden indexicaltheories of attitude ascription. To conclude I indicate a number oframifications that the proposed theory has for issues in epistemology,philosophy of mind, (...) and formal semantics. (shrink)