Singular definite expressions with a unique denotatum and the limits of properhood

The issue addressed is that of whether singular definite expressions with unique denotata, e.g. the zodiac, are proper names or not. These are analyzed as special cases of a class of expressions ambiguous between a proper and a common meaning, e.g. the w/West b/Bank. The ambiguity of this type is held to be a function of different modes of reference, grounded in different intentions of the speaker or hearer: onomastic reference, i.e. intension-free; or semantic reference, i.e. reference mediated by word meaning in the standard way. Under different intentions, therefore, the expressions in question are either proper or common. Properhood is therefore a function of the former type of reference, and not a structural category. A problem in the philosophy of science that this view provokes is addressed