  Propositional attitudes also raise a different kind of issue. Attributions of such attitudes violate extensionality. If Mary is the Dean, still Tom’s believing that the Dean sings well is not the same as his believing that Mary sings well, since her accession to the Deanship may be unknown to him. Quine escapes this sort of problem by taking an attribution of belief to express a relation between the believer and a sentence, understood to be, in the usual case, in the language of the ascriber (not the language of the believer, where the languages differ).