On a simple and neat view, sometimes called the Relational Analysis of Attitude Ascriptions, a belief ascription on the form ‘S believes that x is F’ is correct if, and only if, S stands in the belief-relation to the proposition designated by ‘that x is F’, i.e., the proposition that x is F. It follows from this view that, for a person to believe, say, that x is a boat, there is one unique proposition that she has to believe. This (...) paper argues against this view. It fails, I contend, to make sense of peripheral concept variation. As we attribute and individuate concepts, two people’s concepts C1 and C2 count as e.g., concepts of boats even if their concepts have different extensions in peripheral, or borderline, cases of boats. Thus, A and B can believe that x is a boat through believing peripherally different propositions. It follows that there is no unique proposition that a person has to believe in order to believe e.g., that x is a boat. (shrink)